# Patent

## Title
Flux-cored wire for welding ultrahigh tensile strength steel

## Abstract

In a flux-cored wire for welding an ultrahigh tensile strength steel, one or more of CaF2, BaF2, SrF2, and MgF2 are included in the wire and, when a total amount thereof is defined as α, the α is more than 2.0% and equal to or less than 8.0% in terms of mass % with respect to a total mass of the wire, one or more of Ti oxide, Si oxide, Mg oxide, and Al oxide are included in the wire and, when a total amount thereof is defined as β, the β is 0.01% to 1.20% in terms of mass % with respect to the total mass of the wire, a ratio of an amount of the CaF2 with respect to the α is 0.50 or more, a ratio of the α with respect to the β is 2.0 to 800.0, and Ceq defined in the following expression is 0.60% to 1.20%, Ceq=[C]+[Si]/24+[Mn]/6+[Ni]/40+[Cr]/5+[Mo]/4+[V]/14.

## Background
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a flux-cored wire that is used for welding ultrahigh tensile strength steel having a tensile strength of 950 MPa to 1500 MPa, and particularly, to a flux-cored wire for welding ultrahigh tensile strength steel by which ductility-dip cracking that occurs in an ultrahigh strength weld metal is prevented and a weld metal having excellent strength, toughness, and elongation is obtained.
Priority is claimed on Japanese Patent Application No. 2012-106607, filed on May 8, 2012, the content of which is incorporated herein by reference.
RELATED ART
Recently, demand has been growing for an increase in size and a reduction in weight of a construction machine and an industrial machine such as a construction crane. According to such demand, with regard to a steel plate, an ultrahigh tensile strength steel plate such as 950 MPa-class steel and 1180 MPa-class steel has been used. The reason why the ultrahigh tensile strength steel plate is used is as follows. That is, a reduction of a manufacturing period and a reduction of construction costs are expected in consideration of a reduction of steel costs or a transportation cost due to a reduction in weight of products and a decrease in the amount of steel used, or in consideration of satisfactory handling and a reduction in a welding amount due to a reduction in thickness and a reduction in individual weight of the steel.
However, even though the demand for a use of the ultrahigh tensile strength steel has significantly increased, a used amount of the ultrahigh tensile strength steel of 950 MPa-class or higher is still small in light of the total consumption.
With regard to this situation, the following reasons may be considered. In welding of ultrahigh tensile strength steel of 950 MPa-class or higher, it is difficult to obtain high-strength and high-toughness weld metal with a performance suitable for a base-metal steel plate, and thus development of a welding material suitable for the welding has not been sufficiently performed.
In the welding of the ultrahigh tensile strength steel, it is necessary to obtain a high-alloy weld metal. As a high-alloy welding wire, a flux-cored wire is advantageous in consideration of manufacturability, and thus it is necessary to develop a flux-cored wire that is applicable to welding of, particularly, ultrahigh tensile strength steel.
In consideration of the above-described situation, the following flux-cored wire has been suggested to secure strength or toughness necessary for welding ultrahigh tensile strength steel.
In Patent Document 1, Ni Mo, W, Nb, V, and the like, which are effective to secure strength and toughness, are added in an appropriate amount, thereby securing tensile strength and toughness of a weld metal. In addition, there is suggested a flux-cored wire which contains Si, Mn, Al, Ti, and Mg in a wire as deoxidizing elements in an appropriate amount to prevent a decrease in toughness and ductility of the weld metal due to oxygen and diffusible hydrogen in the weld metal during welding, and which is capable of lowering a critical preheating temperature during a y-groove weld cracking test to 150° C. or lower.
In addition, Patent Document 2 by the present inventors suggests a flux-cored wire in which in welding of ultrahigh tensile strength steel having a tensile strength of 950 MPa-class or higher, Mg is added to a flux to reduce the amount of diffusible hydrogen of a weld metal, particularly, so as to realize welding at a preheating temperature of 100° C., thereby obtaining a weld metal which has high toughness and in which low-temperature cracking resistance is improved.
Patent Document 3 discloses a flux-cored wire for high tensile strength steel of 490 MPa to 780 MPa-class to which metal fluoride and metal oxide are added. However, no examinations have been made on ductility-dip cracking that is problematic in high tensile strength steel with a strength level more than 780 MPa-class.
Patent Document 4 discloses a flux-cored wire to which metal fluoride capable of forming satisfactory beads without generating pores such as a pit or a gas groove even in welding of primer-coated steel or rusted steel is added. However, the flux-cored wire is a low-strength welding material and contains almost no C, Mn, and other alloy components, and thus metal oxide is a main component in a flux composition. In addition, an examination on ductility-dip cracking and toughness of a weld metal are also not made. In addition, in Patent Document 4, it is described that the metal fluoride reduces an amount of diffusible hydrogen, but the amount of the metal fluoride is also 2.0% or less, and quantitative analysis on the reduction effect is not performed.
PRIOR ART DOCUMENT
Patent Document 


    [Patent Document 1] Japanese Unexamined Patent Application, First Publication No. 2008-093715
    [Patent Document 2] Japanese Unexamined Patent Application, First Publication No. 2011-005531
    [Patent Document 3] Japanese Unexamined Patent Application, First Publication No. H08-257785
    [Patent Document 4] Japanese Unexamined Patent Application, First Publication No. H03-180298


Non-Patent Document


    [Non-Patent Document 1] Journal of the Japan Welding Society, “Advanced course of New Welding and Jointing Technology” published in 2005, SANPO PUBLICATIONS, INC. in Tokyo, page 141


DISCLOSURE OF THE INVENTION
Problems to be Solved by the Invention
In a weld joint of the ultrahigh tensile strength steel having a tensile strength of 950 MPa or higher, there is demand for a weld metal to have ultrahigh tensile strength similar to steel, but in a weld metal having such ultrahigh tensile strength, a problem of ductility-dip cracking has arisen.
Ductility-dip cracking is a phenomenon that occurs when a prior γ-grain boundary is cracked during multilayer welding. Welding of the ultrahigh tensile strength steel is performed as multilayer welding, since it is preferable for the welding of the ultrahigh tensile strength steel to limit a heat input per pass. In the multilayer welding, a weld metal that is formed in advance is reheated by the subsequent welding pass. At this time, C and S segregate at the prior γ-grain boundary, and the prior γ-grain boundary that becomes brittle due to the segregation cracks because of thermal contraction that occurs during cooling, which thereby leads to ductility-dip cracking.
Ductility-dip cracking is not found in a weld metal of typical high tensile strength steel. However, in a weld metal of ultrahigh tensile strength steel exceeding 950 MPa, it is necessary to employ a martensite structure by having a high-alloy weld metal so as to secure strength and toughness. Therefore, in the weld metal, significant ductility-dip cracking occurs.
Ductility-dip cracking is a very minute cracking. Ductility-dip cracking decreases elongation, since stress concentrates on tips of the crack to readily cause fracture during a tensile test. When the elongation is low, the following problem and the like occur. That is, sufficient bending cannot be performed during manufacturing.
Accordingly, there is strong demand for a flux-cored welding wire, from which a weld metal having excellent strength, toughness, and elongation is obtained, in order for the ultrahigh tensile strength steel to be widely used.
However, in Patent Documents 1, 2, 3, and 4, no examination is made on ductility-dip cracking that is problematic in the welding of high tensile strength steel having a tensile strength of 950 MPa or higher. Therefore, there is demand for a solution. In addition, there is further demand for a reduction in a preheating temperature during welding of the steel.
In addition, in Patent Document 1, ductility of a weld metal is also considered. However, when referring, for example, to Table 5 of Patent Document 1, the ductility is evaluated as absorbed energy of a Charpy impact test at −40° C., and the ductility is improved by a reduction in an amount of oxygen. When considering the above-described situation, “ductility” described in Patent Document 1 is used with the same meaning as “toughness”.
On the other hand, for example, ductility-dip cracking that is problematic in the invention is cracking due to locally deficiency of ductility in a micro-unit at the prior γ-grain boundary which is defined in Non-Patent Document 1, and definition of ductility-dip cracking is different from that of the ductility used in Patent Document 1. Actually, in the invention, an evaluation index of the ductility is fracture elongation in a tensile test that is performed at room temperature as described in the following Examples.
The invention is made in consideration of the problem in the related art, and an object thereof is to provide a flux-cored wire capable of obtaining a welded joint which has high strength and high toughness and which is excellent in elongation by suppressing ductility-dip cracking during the welding of ultrahigh tensile strength steel having a tensile strength of 950 MPa to 1500 MPa.
Means for Solving the Problem
In the related art, ductility-dip cracking does not occur at a low strength level, and ductility-dip cracking has not been problematic until now. Therefore, no examination has been made on suppression of ductility-dip cracking.
The present inventors performed various examinations with regard to suppressing ductility-dip cracking. As a result, they obtained the following findings. Specifically, with regard to a flux-cored wire in which a flux is filled inside an outer steel sheath, when adding metal fluoride, C, Mn, and V to a wire under specific conditions in a flux blending and alloy composition range necessary to secure strength and toughness for a weld metal of 950 MPa or higher, ductility-dip cracking can be suppressed, and thus excellent fracture elongation is obtained. The present inventors performed an additional examination on the basis of the above finding, thereby accomplishing the invention.
That is, the gist of the invention in combination with preferred embodiments is as follows.
(1) A flux-cored wire for welding an ultrahigh tensile strength steel according to a first aspect of the present invention is a flux-cored wire for gas-shielded arc welding, the flux-cored wire including: an outer steel sheath; and a flux filled into the outer steel sheath, wherein one or more of CaF2, BaF2, SrF2, and MgF2 are included in the wire and, when a total amount thereof is defined as α, the α is more than 2.0% and equal to or less than 8.0% in terms of mass % with respect to a total mass of the wire, one or more of Ti oxide, Si oxide, Mg oxide, and Al oxide are included in the wire and, when a total amount thereof is defined as β, the β is 0.01% to 1.20% in terms of mass % with respect to the total mass of the wire, a total amount of CaCO3, BaCO3, SrCO3, and MgCO3 is less than 0.60% in terms of mass % with respect to the total mass of the wire, an amount of an iron powder in the flux is less than 5.0% in terms of mass % with respect to the total mass of the wire, a ratio of an amount of the CaF2 with respect to the α is 0.50 or more, a ratio of the α with respect to the β is 2.0 to 800.0, a chemical composition includes, in terms of mass % with respect to the total mass of the wire, C: more than 0.080% and equal to or less than 0.200%, Si: 0.05% to 1.50%, Mn: 1.0% to 2.2%, Al: 0.001% to 0.400%, Ni: 1.0% to 9.0%, V: more than 0.050% and equal to or less than 0.300%, P: 0.020% or less, S: 0.020% or less, Cu: 0% to 0.800%, Cr: 0% to 2.5%, Mo: 0% to 2.0%, Ti: 0% to 0.300%, Nb: 0% to 0.05%, B: 0% to 0.0100%, Mg: 0% to 0.8%, Ca: 0% to 0.5%, REM: 0% to 0.0100%, and remainder: iron and impurities, and Ceq defined in following Expression a is 0.60% to 1.20%,

Ceq=[C]+[Si]/24+[Mn]/6+[Ni]/40+[Cr]/5+[Mo]/4+[V]/14  (a)

in which elements noted in brackets represent amounts of the respective elements in terms of mass %.
(2) In the flux-cored wire for welding the ultrahigh tensile strength steel according to (1), an amount of CaO in the wire may be less than 0.15% in terms of mass % with respect to the total mass of the wire.
(3) In the flux-cored wire for welding the ultrahigh tensile strength steel according to (1) or (2), the ratio of the amount of CaF2 to the α may be 0.90 or more.
(4) In the flux-cored wire for welding the ultrahigh tensile strength steel according to any one of (1) to (3), with regard to a tensile test of a deposited metal which is defined in Japanese Industrial Standards JIS Z 3111-2005 with respect to gas-shielded arc welding using the wire, the tensile strength of the deposited metal may be 950 MPa to 1500 MPa.
(5) In the flux-cored wire for welding the ultrahigh tensile strength steel according to any one of (1) to (4), a slit-shaped gap may not exist in the outer steel sheath.
(6) In the flux-cored wire for welding the ultrahigh tensile strength steel according to any one of (1) to (5), a perfluoropolyether oil may be applied onto a surface of the wire.
Effects of the Invention
According to the invention, with regard to a flux-cored wire that is used in welding ultrahigh tensile strength steel having a tensile strength of 950 MPa or higher, it is possible to provide a flux-cored wire capable of obtaining a weld metal which has high strength and high toughness and which is excellent in elongation by suppressing ductility-dip cracking.



BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a view illustrating a relationship between fracture elongation (gauge length: 50 mm) that is obtained in a tensile test of a No. Al round bar tensile test specimen in accordance with JIS Z 3111 (1986) and an amount of metal fluoride/an amount of metal oxide.
FIG. 2 is a view illustrating a relationship between fracture elongation (gauge length: 50 mm) that is obtained in a tensile test of a No. Al round bar tensile test specimen in accordance with JIS Z 3111 (1986) and an amount of C in a wire.
FIG. 3 is a view illustrating a test specimen collecting position in Examples (JIS Z 3111 (1986)).
FIG. 4A is a view illustrating a shape of an oxide in a weld metal after welding using a wire of the related art, and shows transmission electron microscopy photographs of two oxides.
FIG. 4B is a view illustrating the shape of the oxide in the weld metal after welding using the wire of the related art, and shows results obtained by EDS analysis with respect to a surface-layer C point of the oxides in the photographs of FIG. 4A.
FIG. 5A is a view illustrating a shape of an oxide in a weld metal after welding using a wire of the invention, and shows transmission electron microscopy photographs of two oxides.
FIG. 5B is a view illustrating the shape of the oxide in the weld metal after welding using the wire of the invention, and shows results obtained by EDS analysis with respect to a surface-layer C point of the oxide in the photographs of FIG. 5A.
FIG. 6A is a view illustrating an example of results obtained by observation with a transmission electron microscope with respect to the inside of an oxide in the weld metal after welding using the wire of the invention, and shows an image of the oxide.
FIG. 6B is a view illustrating an example of results obtained by observation with the transmission electron microscope with respect to the inside of an oxide in the weld metal after welding using the wire of the invention, and shows EDS analysis map results of the oxide.
FIG. 6C is a view illustrating an example of results obtained by observation with the transmission electron microscope with respect to the inside of an oxide in the weld metal after welding using the wire of the invention, and shows a distribution of oxygen.
FIG. 6D is a view illustrating an example of results obtained by observation with the transmission electron microscope with respect to the inside of an oxide in the weld metal after welding using the wire of the invention, and shows a distribution of S.
FIG. 7 is a view illustrating a test specimen collecting position in Examples (JIS Z 3111 (2005)).
FIG. 8 is a view illustrating a relationship between an amount of CaO and an amount of diffusible hydrogen.



EMBODIMENTS OF THE INVENTION
In a steel plate 1 that is a target of the invention, the strength (tensile strength) of a weld metal that is to be formed is as high as 950 MPa to 1500 MPa, and the weld metal of the ultrahigh strength steel plate has a structure in which there is 90% or more of martensite. In the weld metal in a welded state, a prior γ-grain boundary is very coarse. In addition, a martensite transformation is a diffusionless transformation, and thus the γ-grain boundary that is formed during welding remains in a state of including segregates and impurities. Accordingly, toughness of the prior γ-grain boundary of the ultrahigh strength weld metal is originally low.
In addition, C enters a solid-solution state due to the martensite transformation. When such a weld metal is reheated during multilayer welding, C segregates at the coarse prior γ-grain boundary, and causes significant embrittlement. Similarly, S also segregates at the prior γ-grain boundary due to reheating during the multilayer welding, and thus causes embrittlement. In this state, cracking occurs in the prior γ-grain boundary due to thermal contraction that occurs during cooling, whereby ductility-dip cracking occurs.
With regard to the problem, the present inventors examined means for preventing segregation at a grain boundary by effectively trapping C and S in a grain or means for increasing elongation property of a weld metal. As a result, the present inventors obtained the following finding. When adding a metal fluoride, a metal oxide, C, Mn, and V in an appropriate amount, even in an ultrahigh strength weld metal, it is possible to suppress ductility-dip cracking, and thus it is possible to secure excellent fracture elongation.
An example of an experiment from which the finding is obtained will be described.
The present inventors adjusted composition of the wire similar to an example described in the following Examples to prepare seamless flux-cored wires having an finishing wire diameter φ of 1.2 mm. In the prepared wires, particularly, the amount of C, Mn, and V, and the amount of the metal fluoride and the metal oxide were changed.
Butt welding of a 950 MPa-class steel plate 1 was performed using the flux-cored wires, and No. Al cylindrical tensile test specimens according to JIS Z 3111 (1986) were collected from weld metals that were obtained. Then, a tensile test was performed at room temperature to evaluate tensile strength and fracture elongation of the weld metals.
FIG. 1 illustrates a relationship between the fracture elongation (gauge length: 50 mm) that was obtained from the tensile test, and an amount of a metal fluoride/an amount of a metal oxide in a welding wire. Here, a symbol ∘ and a symbol • represent that V is more than 0.05%, and a symbol x represents that V is 0.05% or less. In addition, FIG. 2 illustrates a relationship between the fracture elongation (gauge length: 50 mm) that was obtained from the tensile test, and an amount of C in the wire.
From FIG. 1, in the wire in which the metal fluoride is added in order for a value of the amount of the metal fluoride/the amount of the metal oxide to be 2.0 or more, and C is added in an amount of more than 0.080% in terms of mass %, Mn is added in an amount of 1.0% or more in terms of mass %, and V is added in an amount of more than 0.05% in terms of mass %, it can be seen that fracture elongation of 12% or more was obtained in the tensile test.
In addition, from FIG. 2, in a range in which the amount of Mn in the wire was less than 1%, the fracture elongation decreases along with an increase in the amount of C in the wire. On the other hand, in a range in which the amount of Mn in the wire is 1% or more, the fracture elongation shows the same tendency as a case in which the amount of Mn is small when the amount of C in the wire is up to the vicinity of 0.07%. However, in contrast, when the amount of C exceeds 0.07%, the fracture elongation rapidly increases along with an increase in the amount of C in the wire. When the amount of C in the wire is 0.080% or more, it can be seen that excellent fracture elongation of 12% or more is exhibited.
The reason why the above-described results are obtained is considered as follows.
(i) When the metal fluoride is added to a flux in a specific range so as to establish a specific relationship with the metal oxide, S is trapped in an oxide during solidification, whereby a solid-solution amount of S is reduced and segregation of S during reheating at a prior γ-grain boundary is suppressed. As a result, it is considered that an effect of suppressing ductility-dip cracking is obtained.
The assumption is based on experiment results as shown in FIGS. 4A to 6D.
FIGS. 4A and 4B illustrate an example of results obtained by observation with a transmission electron microscope on a plurality of oxides in a weld metal after welding using a wire of the related art with respect to two oxides 1 and 2. FIG. 4A shows transmission electron microscopy photographs of the oxides, and FIG. 4B shows results obtained by EDS analysis with respect to a surface-layer C point of the oxides in the photographs of FIG. 4A. From the EDS analysis results, it can be seen that S is hardly detected in this example.
On the other hand, FIGS. 5A and 5B illustrate an example of results obtained after welding by using the wire of the invention (that is, a wire to which a metal fluoride is added in a specific range to establish a specific relationship with a metal oxide) with respect to two oxides A and B in the same manner as shown in FIGS. 4A and 4B. From the EDS analysis results, it can be seen that S is detected and apparently exists on an oxide surface layer in this example.
FIGS. 6A to 6D illustrate an example of results obtained by observation with a transmission electron microscope with respect to the inside of an oxide in the weld metal after welding using the wire of the invention and performing an ion milling treatment to obtain a thin film, and from EDS element maps of the inside of the oxide which are shown in FIGS. 6B, 6C, and 6D, it can be apparently seen that S exists on the oxide surface.
From these results, it is considered that the following effect is obtained in the weld metal after welding using the wire of the invention. That is, a large amount of S is trapped in the oxide surface layer during solidification, and thus an amount of solid-solution S greatly decreases. Accordingly, segregation of S at the prior γ-grain boundary is suppressed, and this suppression is effective for suppression of ductility-dip cracking.
(ii) In addition, it is considered that an effect of delaying the segregation of the solid-solution C at the prior γ-grain boundary is obtained, since Mn in the weld metal has an attractive interaction with C. In addition to this, V tends to form a carbide with C, segregation of V during solidification is less, and V exists in a state of being distributed in the weld metal in a relatively uniform manner. If Mn and V are added together to the weld metal, when the weld metal is reheated, a migration speed of C toward the prior γ-grain boundary decreases due to the attractive interaction with Mn, and V forms a carbide with the solid-solution C in a γ-grain in the meanwhile, and thus it is considered that the segregation of C with respect to the prior γ-grain boundary is suppressed.
(iii) In addition, the carbide that precipitates in the prior γ-grain is minutely distributed and thus contributes to strength improvement, thereby decreasing a difference in strength in the weld metal. In addition, as an amount of C increases, an amount of precipitate increases, thereby decreasing the difference in strength in the weld metal. Accordingly, when an amount of C is raised and Mn and V are added together, the carbide precipitates with being minutely dispersed in the prior γ-grain, and uniform plastic deformation occurs in the entirety of the weld metal during working, and thus it is considered that an effect of improving fracture elongation is obtained.
Next, the reason for limiting characteristic technical requirements with respect to the flux-cored wire of Examples, to which the results of the above-described examination are applied, will be sequentially described.
First, a description will be given with respect to the reason for limiting the amount of alloy composition, metal deoxidizing composition, and other composition which are contained in an outer steel sheath and a flux which constitute the flux-cored wire of Examples.
In the following description, “%” represents “mass %” unless otherwise stated, and an amount of each composition represents a total amount of the composition in the outer steel sheath and the flux in terms of mass % with respect to the total mass of the wire.
(C: More than 0.080 and Equal to or Less than 0.200%)
When the tensile strength of the weld metal is 950 MPa or more, a structure is mainly composed of martensite. An effect of C on the strength of the martensite structure is large. In addition, the larger an amount of C in a welding wire is, the further the amount of C in the weld metal increases, thereby increasing the strength of the weld metal.
In addition, in a case where Mn and V are added together in the range of the invention, a carbide precipitates with being minutely dispersed in the prior γ-grain, thereby decreasing a difference in strength in the weld metal. According to this, uniform plastic deformation occurs in the weld metal during working, and thus the fracture elongation can be improved.
To obtain the effects, it is necessary that C be contained in an amount that is more than 0.080%. However, when C is contained in an amount that is more than 0.200%, deterioration in toughness becomes significant, and thus this range is not preferable. In addition, to stably secure the strength and the fracture elongation, the lower limit of C may be set to be more than 0.090%, more than 0.100%, or more than 0.110%, and the upper limit of C may be set to 0.180%, 0.160%, or 0.140%.
(Si: 0.05% to 1.50%)
Si is a deoxidizing element, and it is necessary for Si to be contained in an amount that is more than 0.05% to reduce an amount of O in the weld metal and to increase a degree of cleanliness of the weld metal. However, when Si is contained in an amount that is more than 1.50%, the toughness of the weld metal deteriorates, and thus the amount of Si is set to 0.05% to 1.50%. In addition, to stably secure the toughness of the weld metal, the lower limit of Si may be set to 0.20%, 0.30%, or 0.40%, and the upper limit of Si may be set to 1.20%, 1.00%, or 0.80%.
(Mn: 1.0% to 2.2%)
Mn has an attractive interaction with C, and suppresses segregation of C at the prior γ-grain boundary. Accordingly, Mn is effective for suppression of ductility-dip cracking. In addition, in the composition range of the invention, Mn promotes generation of a minute carbide in the prior γ-grain, and decreases the difference in strength in the weld metal. Accordingly, Mn has an effect of improving the fracture elongation.
To reliably exhibit the effect, it is necessary that Mn be contained in an amount of 1.0% or more. On the other hand, when Mn is contained in an amount that is more than 2.2%, residual austenite is excessively generated in the weld metal. C is concentrated in the residual austenite. When being reheated by welding in this state, a carbide is excessively generated at a residual austenite site, and thus significant embrittlement is caused.
Accordingly, the amount of Mn is set to 1.0% to 2.2%. In addition, to stably secure the effect of improving the fracture elongation, the lower limit of Mn may be set to 1.2%, 1.3%, or 1.4%, and the upper limit of Mn may be set to 2.0% or 1.8%.
(P: 0.020% or Less)
P is an impurity element, and P deteriorates the toughness and ductility of the weld metal. Accordingly, it is necessary to reduce P as much as possible. As a range capable of permitting an adverse effect against the toughness and the ductility, an amount of P is set to 0.020% or less. To further improve the toughness and the ductility, the upper limit of P may be limited to 0.015% or 0.010%. It is not necessary to limit the lower limit of P and the lower limit may be set to 0%.
(S: 0.020% or Less)
S is also an impurity element, and promotes generation of ductility-dip cracking. In addition, when S excessively exists, the toughness and the ductility deteriorate, and thus it is necessary to reduce S as much as possible. As a range capable of permitting an adverse effect against the toughness and the ductility, an amount of S is set to 0.020% or less. To further improve the toughness, the upper limit of S may be limited to 0.015%, 0.010%, or 0.008%. It is not necessary to limit the lower limit of S, and the lower limit may be set to 0%.
(Al: 0.001% to 0.400%)
Al is a deoxidizing element and is effective for reduction of 0 in the weld metal and effective for improvement in the degree of cleanliness, similar to Si. To exhibit the effect, Al is contained in an amount of 0.001% or more. On the other hand, when Al is contained in an amount that is more than 0.400%, Al forms a nitride or an oxide to deteriorate the toughness of the weld metal. Accordingly, the amount of Al is set to 0.001% to 0.400%. In addition, to sufficiently obtain the effect of improving the toughness of the weld metal, the lower limit of Al may be set to 0.0012% or 0.0015%. In addition, the upper limit of Al may be set to 0.200%, 0.100%, or 0.080% to suppress generation of a coarse oxide.
(Ni: 1.0% to 9.0%)
Ni is a unique element capable of improving the toughness regardless of a structure and composition due to solid-solution toughening (effect of increasing the toughness due to solid-solution), and is an element effective to increase the toughness in a high-strength weld metal having a tensile strength of 950 MPa or more.
To obtain the solid-solution toughening effect, it is preferable that 1.0% or more of Ni be contained. The more the amount of Ni is, the more advantageous for improvement in the toughness. However, when the amount of Ni is more than 9.0%, the effect is saturated, and in addition to this saturation, the manufacturing costs of the welding wire becomes excessive, and thus this range is not preferable. Therefore, when Ni is contained, the amount of Ni is set to 1.0% to 9.0%. In addition, the lower limit of Ni may be set to 1.4%, 1.6%, or 2.1% in order for the effect of Ni to reliably contribute to the improvement in the toughness. In addition, Ni is an expensive element, and the upper limit may be limited to 7.0%, 6.0%, or 4.8%.
(V: More than 0.005% and Equal to or Less than 0.300%)
V is less likely to segregate during welding solidification, and exists in the weld metal in a state of being distributed in a relatively uniform manner. When the weld metal is reheated, V traps the solid-solution C to form a carbide, thereby suppressing segregation of C at the prior γ-grain boundary. According to this, V is effective for suppression of ductility-dip cracking that occurs in an ultrahigh strength weld metal. In addition, in the composition range of the invention, V forms a minute carbide in the prior γ-grain and precipitates therein, and decreases the difference in strength in the weld metal. As a result, V has an effect of improving the fracture elongation.
To obtain the effect, it is necessary for V to be contained in an amount that is more than 0.050%. The more the amount of V is, the further the effect of suppressing ductility-dip cracking increases. However, when the amount of V is more than 0.300%, the effect is saturated, and in addition to this saturation, the toughness deteriorates, and thus, this range is not preferable. In addition, the lower limit of V may be set to 0.060%, 0.080%, 0.100%, or 0.120% to further increase the effect of suppressing ductility-dip cracking, and the upper limit of V may be limited to 0.280%, 0.250%, or 0.230% to suppress deterioration in the toughness due to V.
In addition to the above-described basic composition as the alloy composition or the metal deoxidizing composition, the flux-cored wire of the invention may contain one or more of Cu, Cr, Mo, Ti, Nb, B, Mg, Ca, and REM in accordance with a strength level of the steel plate 1 to be welded or a degree of toughness that is demanded. Regardless of whether or not the composition are intentionally added, the amount of the composition in the wire is in the range described in the claims, and the wire is regarded to be in the range of the invention. Accordingly, in the invention, the upper limit of the alloy composition is only defined, and thus a description in the claims may be any one of “set to (0 to the upper limit)”, “set to (be equal to or less than the upper limit)”, or “limited to (be equal to or less than the upper limit)”.
(Cu: 0% to 0.800%)
Cu is added as an elementary substance or an alloy into plating on an outer sheath surface or the flux of the wire, and suppresses the segregation of C in the prior γ-grain. As a result, Cu has an effect of suppressing ductility-dip cracking. 0.800% or less of Cu may be contained to obtain the effect. On the other hand, when the amount of Cu is more than 0.800%, the toughness decreases. Accordingly, when Cu is contained, the amount of Cu is set to 0.800% or less.
Additionally, the amount of Cu includes a portion contained in the outer sheath itself and/or the flux, and further includes a portion contained in a copper plating when the copper plating is performed on a surface of the wire. The upper limit of Cu may be set to 0.600%, 0.500%, or 0.400% to obtain the effect of Cu in a more stable manner. It is not necessary to determine the lower limit of Cu, and the lower limit is 0%. The lower limit may be set to 0.050% or 0.100% as necessary.
(Cr: 0% to 2.5%)
Cr is an element that is effective for high-strengthening by increasing hardenability. 0.1% or more of Cr may be contained to obtain the effect. On the other hand, if Cr is excessively contained in an amount that is more than 2.5%, nonuniform curing of bainite and/or martensite is caused to occur, and thus the toughness deteriorates. Therefore, when Cr is contained, the amount of Cr is set to 2.5% or less. The upper limit of Cr may be set to 2.0%, 1.8%, 1.6%, or 1.4% to stably obtain the effect of Cr. It is not necessary to determine the lower limit of Cr, and the lower limit is 0%.
(Mo: 0% to 2.0%)
Mo is an element improving the hardenability. In addition, Mo forms a minute carbide, and is effective to secure the tensile strength due to precipitation strengthening. 0.1% of Mo may be contained to exhibit the effect. On the other hand, when Mo is contained in the welding wire in an amount that is more than 2.0%, a coarse precipitate is generated to deteriorate the toughness of the weld metal. Therefore, when Mo is contained in the welding wire, the amount of Mo is set to 2.0% or less. The upper limit of Mo may be set to 1.8%, 1.6%, 1.4%, or 1.2% to obtain the effect of Mo in a more stable manner. It is not necessary to determine the lower limit of Mo, and the lower limit is 0%.
(Ti: 0% to 0.300%)
Similar to Al, Ti is effective as a deoxidizing element, and has an effect of reducing an amount of O in the weld metal. In addition, Ti is effective to fix solid-solution N to mitigate an adverse effect of the solid-solution N on the toughness. 0.005% or more of Ti may be contained to exhibit the effect. However, when the amount of Ti in the welding wire is more than 0.300% and becomes excessive, possibilities of occurrence of deterioration in the toughness due to formation of a coarse oxide and occurrence of deterioration in the toughness due to excessive precipitation strengthening increase.
Therefore, when Ti is contained in the welding wire, the amount of Ti is set to 0.300% or less. It is not necessary to determine the lower limit of Ti, and the lower limit is 0%. In addition, the upper limit of Ti may be set to 0.200%, 0.100%, or 0.050% to sufficiently obtain the toughness improvement effect of the weld metal due to Ti.
(Nb: 0% to 0.05%)
Nb forms a minute carbide, and is effective to secure the tensile strength due to precipitation strengthening. To obtain the effect, even when considering a composite effect with an element having the same effect, 0.01% or more of Nb may be contained. On the other hand, when Nb is contained in an amount that is more than 0.05%, Nb is excessively contained in the weld metal, and forms a coarse precipitate, thereby deteriorating the toughness. Therefore, this range is not preferable.
Accordingly, in the invention, when Nb is contained in the welding wire, the amount of Nb is set to 0.05% or less. It is not necessary to determine the lower limit of Nb, and the lower limit is 0%. To obtain the effect of Nb in a more stable manner, the upper limit of Nb may be set to 0.04% or 0.035% as necessary, and the lower limit of Nb may be set to 0.02% to 0.03%.
(B: 0% to 0.0100%)
When B is contained in the weld metal in an appropriate amount, B is coupled to solid-solution N to form BN. Accordingly, B has an effect of reducing an adverse effect on the toughness of the solid-solution N. In addition, B increases hardenability, and has an effect of contributing to improvement in strength. 0.0003% or more of B may be contained in the welding wire to obtain these effects. On the other hand, when the amount of B is more than 0.0100%, B in the weld metal becomes excessive, and coarse B compounds such as BN and Fe23(C, B)6 are formed, and conversely the toughness deteriorates. Therefore, this range is not preferable.
Accordingly, when B is contained, the amount of B is set to 0.0100% or less. It is not necessary to determine the lower limit of B, and the lower limit is 0%. For improvement in the toughness, the upper limit of B may be set to 0.0080%, 0.0060%, 0.0040%, or 0.0030%, and the lower limit of B may set to 0.0004% or 0.0005%.
(Mg: 0% to 0.8%)
Mg is a strongly deoxidizing element, and reduces an amount of O in the weld metal to improve the toughness and the ductility of the weld metal. 0.1% or more of Mg may be contained to obtain this effect. However, when the amount of Mg in the welding wire is more than 0.8%, a decrease in the toughness due to generation of a coarse oxide in the weld metal is considerable, and stability of arc during welding deteriorates, and thus deterioration in an appearance of a bead may be caused in some cases.
Therefore, when Mg is contained, the amount of Mg is set to 0.8% or less. It is not necessary to determine the lower limit of Mg, and the lower limit is 0%. For securement of stability in welding work, the upper limit of Mg may be set to 0.7% or 0.6%, and the lower limit of Mg may be set to 0.2% or 0.3%.
(Ca: 0% to 0.5%)
(REM: 0% to 0.0100%)
Both of Ca and REM change a structure of sulfides and make the size of sulfides and oxides in the weld metal fine, and thus Ca and REM are effective for improvement in the ductility and the toughness. Ca or REM may be contained to obtain this effect. On the other hand, when Ca and REM are excessively contained, coarsening of the sulfides or the oxides is caused to occur, and thus deterioration in the ductility and the toughness is caused to occur. In addition, when Ca and REM are excessively contained, deterioration in the appearance of the weld bead 3 and deterioration in welding properties may occur. Therefore, the upper limit of Ca is set to 0.5%, and the upper limit of REM is set to 0.0100%. It is not necessary to determine the lower limit of Ca and REM, and the lower limit is 0%.
(Carbon Equivalent Ceq: 0.60% to 1.20%)
The flux-cored wire of the invention contains the respective elements as the alloy composition and the metal deoxidizing composition as described above. To secure the tensile strength of the weld metal, the amounts of C, Si, Mn, Ni, Cr, Mo, and V are further adjusted in such a manner that a carbon equivalent Ceq determined by Japan Welding Engineering Soc. (WES) which is expressed by the following Expression a becomes 0.60% to 1.20%.

Ceq=[C]+[Si]/24+[Mn]/6+[Ni]/40+[Cr]/5+[Mo]/4+[V]/14  (a)

Provided that, the elements in square brackets represent amounts of the respective elements in terms of mass %.
As a value of Ceq is high, the weld metal is hardened, and thus the tensile strength is improved. On the other hand, as a value of Ceq is high, the toughness decreases, and welding crack sensitivity increases, and thus it is necessary to provide a countermeasure of suppressing low-temperature cracking. When the Ceq value is less than 0.60%, the target strength (tensile strength) of the weld metal, i.e. 950 MPa or more, is not satisfied. When the Ceq value is more than 1.20%, the tensile strength of the weld metal becomes excessive, and thus the toughness of the weld metal decreases. Accordingly, a range of Ceq is set to 0.60 to 1.20%. The lower limit of Ceq may be set to 0.63%, 0.66%, or 0.70% to increase the tensile strength of the weld metal. The upper limit of Ceq may be set to 1.10%, 1.00%, or 0.90% to decrease deterioration in the toughness of the weld metal.
In addition, the amount of the elements which are contained as the alloy composition or the metal deoxidizing composition as described above does not include the amount of these elements contained in a state of a fluoride, a metal oxide, and a metal carbonate. In addition, it is not necessary for these elements to be a pure substance, and even when the elements are contained in form of an alloy such as Cu—Ni or in form of unavoidable impurities, there is no problem. In addition, even when the elements are contained in the outer steel sheath or the elements are contained as a flux, the effect is the same in each case, and thus the elements may be contained in either the outer steel sheath or the flux.
Next, chemical composition of a flux that is provided inside the outer sheath of the wire will be described.
In the flux-cored wire of Examples, one or more kinds of metal fluorides of CaF2, BaF2, SrF2, and MgF2 are contained, and the total amount (a) thereof in the wire is set to be more than 2.0% and equal to or less than 8.0%.
The metal fluorides change basicity of a molten pool. When the basicity of the molten pool is changed, trapping of S in the oxide during solidification is promoted. When S trapped in the oxide increases, solid-solution S after solidification decreases. According to this, when the weld metal is reheated, segregation of the solid-solution S at the prior γ-grain boundary is suppressed, and thus it is possible to suppress ductility-dip cracking that occurs in the ultrahigh strength weld metal. In addition, the change in the basicity due to the metal fluorides is effective for reduction of oxygen in the weld metal, and thus improvement in the toughness of the weld metal may be expected.
To obtain these effects, it is necessary for the metal fluorides to be contained with the total amount α being more than 2.0%. When the total amount α of the metal fluorides is 2.0% or less, the effects may not be sufficiently obtained. In addition, when the total amount α is more than 8.0%, welding fume and slug are excessively generated, and thus welding workability significantly deteriorates. Therefore, this range is not preferable. The lower limit of the total amount α may be set to 2.1% or more, 2.2% or more, 2.5% or more, 2.8% or more, or 3.0% or more to further obtain the effect of reducing the amount of oxygen, and the upper limit of the total amount α may be set to 7.0% or less, 6.5% or less, or 6.0% or less to suppress the deterioration in the welding workability.
In addition, as the metal fluorides, any one of CaF2, BaF2, SrF2, and MgF2 may be used in consideration of the effect of suppressing ductility-dip cracking, but CaF2 is set to be contained as a main composition in consideration of the welding workability. In addition, when priority is given to the welding workability such as securement of arc stability and suppression of sputter, among the metal fluorides that are added, a ratio of CaF2 to the total amount α is set to 0.50% or more. That is, the ratio of the amount of CaF2 to α is set to 0.50 or more. This ratio may be set to 80% or more, 90% or more, or 100% or more as necessary.
In the flux-cored wire of Examples, one or more of Ti oxide (for example, TiO2), Si oxide (for example, SiO2), Mg oxide (for example, MgO), and Al oxide (for example, Al2O3) are added as a slug forming agent. These oxides are added as necessary to maintain a satisfactory appearance of the weld bead 3, and it is necessary for the metal oxides to be added in an amount of 0.01% or more with respect to the total mass of the wire to obtain the effect in an appropriate manner. However, when the metal oxides are added with a total amount β thereof being more than 1.20%, an amount of oxygen in the weld metal increases, and the toughness deteriorates, and thus this range is not preferable.
Accordingly, the total amount β of the metal oxides is set to 0.01% to 1.20%. The amount of the metal oxides is set as a total amount including an amount of the metal oxides contained in a binder and the like that are used for granulation of the flux in addition to the total amount of TiO2, SiO2, MgO, and Al2O3. In addition, the upper limit of the total amount β may be set to 1.00%, 0.90%, or 0.80% to suppress deterioration in the toughness due to addition of the metal oxides as much as possible. The lower limit of total amount β may be set to 0.05%, 0.10%, 0.15% or 0.20% as necessary.
To suppress ductility-dip cracking of the ultrahigh strength weld metal, in addition to the amount of each of the metal fluorides and the metal oxides, it is necessary for a ratio of the amount of the metal fluorides in terms of mass % to the amount of metal oxides in terms of mass % (that is, the amount of the metal fluorides/the amount of metal oxides, that is, the total amount α/the total amount β) to be 2.0 to 800.0. When the ratio (α/β) of the amount of the metal fluorides to the amount of metal oxides is less than 2.0, the effect of trapping S by oxides which is necessary to suppress ductility-dip cracking disappears. When the ratio (α/β) of the amount of the metal fluorides to the amount of metal oxides is more than 800.0, an arc state becomes unstable, and thus the appearance of the bead becomes poor. Therefore, this ratio is not preferable. As necessary, the lower limit of the ratio (α/β) may be 3.0, 4.0, or 5.0, and the upper limit thereof may be set to 500, 300, or 200.
An iron powder may be added for adjustment of a filling rate of the flux-cored wire or improvement of deposition efficiency as necessary. The iron powder may not be added, and the lower limit thereof is 0%. However, a surface layer of the iron powder oxidizes, and thus when the iron powder is added, an amount of oxygen in the weld metal increases, thereby decreasing the toughness. When the tensile strength is 950 MPa or more, strength is very high, and thus it is difficult to secure the toughness. Accordingly, an increase in oxygen due to the addition of iron powder is not permitted.
Accordingly, the iron powder may not be added. However, in a case of adding the iron powder to adjust the filling rate, an amount of the iron powder is limited to be less than 5.0% so as to secure the toughness. The upper limit thereof may be limited to 3.0%, 2.0%, or 1.0% to improve the toughness.
In the flux-cored wire of the invention, one or more kinds of metal carbonates of CaCO3, BaCO3, SrCO3, and MgCO3 may be further added to increase an arc stability effect and arc convergence, but when they are added in an amount of 0.60% or more, the arc concentricity becomes too strong, and thus an amount of sputter generation increases. Accordingly, in a case of metal carbonates being contained, a total amount thereof is set to be less than 0.60%. The lower limit of the total amount of metal carbonates is 0%.
In the invention, it is preferable not to intentionally add CaO to the flux. However, CaO may be contained in a raw material of the flux in some cases. When Cao comes into contact with the air, CaO changes to CaOH to increase diffusible hydrogen in the weld metal. In welding of the ultrahigh tensile strength steel, when the diffusible hydrogen increases, load in a preheating process performed to suppress low-temperature cracking increases, and thus this increase is not preferable. Even in a case of being mixed in as an impurity or a case of being intentionally added, it is preferable that an amount of CaO be set to be less than 0.20% in terms of mass % with respect to the total mass of the wire. An experiment from which this finding is obtained is illustrated in FIG. 8. From FIG. 8, it can be seen that as CaO increases, the diffusible hydrogen increases, and up to 0.15%, 1.0 ml/100 g or less of diffusible hydrogen is obtained. Accordingly, it is preferable that CaO be set to be less than 0.15% so as to suppress the load increase in the preheating process. That is, it is preferable to select a raw material of the flux so as to satisfy this range. In addition, the upper limit of the amount of CaO may be set to 0.12%, 0.10%, or 0.08% as necessary.
Hereinbefore, the reason of limiting the composition of the flux-cored wire of the invention has been described, and the other remaining composition include iron and impurities. An iron composition includes Fe in the outer steel sheath, the iron powder that is added to the flux, and Fe in an alloy composition. In addition, the remainder including iron as a main composition may contain impurities that are mixed in in a manufacturing process and the like in a range not deteriorating characteristics of the invention.
In addition to the above-described composition, an arc stabilizer may further be contained as necessary. Examples of the arc stabilizer include oxides or fluorides of Na or K (for example, Na2O, NaF, K2O, KF, K2SiF6, K2ZrF6), and the like, and a total amount of the arc stabilizer is appropriately 0.001% to 0.40%. The arc stabilizer may not be contained, and thus the lower limit thereof is 0%. In addition, the oxides and fluorides, which are exemplified herein, are not included in the metal oxides and the metal fluorides. When the oxides or the fluorides of Na and K are excess, an arc becomes strong, and sputter and the like increase. Accordingly, a total amount of the oxides or the fluorides may be limited to 0.30% or less, 0.20% or less, less than 0.10%, or 0.08% or less as necessary.
The flux-cored wire may be classified roughly into a seamless wire not having a slit-shaped joint in an outer steel sheath, and a wire having a seam provided with a slit-shaped gap at a joint of an outer steel sheath. However, any cross-sectional structure may be employed in the present invention. When the slit-shaped gap exists, moisture in the air penetrates from the gap during storage of the wire, and thus the flux absorbs the moisture. When welding is performed in this state, an amount of the diffusible hydrogen in the weld metal increases. To avoid this, it is preferable to employ the seamless wire not having the slit-shaped joint.
In addition, a method of applying a lubricant having sliding properties onto a surface of the wire to improve wire feedability during welding is generally performed. As the lubricant for a welding wire, a perfluoropolyether oil (PFPE oil) that is a fluorine-based lubricant may be used. The perfluoropolyether oil does not contain a hydrogen source, and thus even when the perfluoropolyether oil is applied to the wire as the lubricant, the perfluoropolyether oil does not increase the diffusible hydrogen of the weld metal.
In the invention, the tensile strength of the weld metal or a deposited metal is set to the same level of tensile strength as that of the ultrahigh tensile strength steel having a tensile strength of 950 MPa to 1500 MPa. The tensile strength of the weld metal or the deposited metal can be measured by performing a tensile test of the weld metal or the deposited metal in a weld joint that is prepared by using the flux-cored wire. In addition, it is known that hardness and the tensile strength have a high correlation. The tensile strength of the weld metal or the deposited metal may be obtained by conversion from the measured hardness of the weld metal or the deposited metal of the weld joint with the correlation. In addition, even when the weld joint is not prepared by using the ultrahigh tensile strength steel, the tensile strength of the weld metal or the deposited metal may be obtained by performing a tensile test of a deposited metal defined in Japanese Industrial Standards JIS Z 3111-2005 as long as the flux-cored wire is available. In addition, the upper limit of the tensile strength of the weld metal or the deposited metal may be limited to 1400 MPa or 1350 MPa as necessary.
The flux-cored wire of the present invention may be manufactured by the same manufacturing process as a typical method of manufacturing flux-cored wire.
First, a steel strip that becomes an outer sheath, and a flux in which a metal fluoride, an alloy composition, a metal oxide, a metal carbonate, and an arc stabilizer are mixed in predetermined amounts are prepared. The steel strip is shaped to an open tube (U-shaped tube) by a shaping roll while feeding the steel strip in a longitudinal direction, thereby obtaining an outer steel sheath. Then, the flux is supplied from an opening of the open tube in the middle of the shaping, and edge surfaces that face at the opening are subjected to butt seam welding. A jointless tube that is obtained by the welding is drawn and is subjected to an annealing treatment in the middle of the drawing or after completing the drawing process, thereby obtaining a seamless wire having intended diameter. In addition, a part is set as a tube having a joint which is not subjected to seam welding, and the tube is drawn to obtain a wire having a seam.
EXAMPLES
Next, enablement and effects of the invention will be described in detail with reference to Examples.
A steel strip was shaped to an open tube by a shaping roll while feeding the steel strip in a longitudinal direction, and a flux was supplied from an opening of the open tube in the middle of the shaping. Edge surfaces that face the opening were subjected to butt seam welding to obtain a tube not having a joint, and annealing was incorporated in the middle of a drawing process of a tabulation wire, thereby preparing a flux-cored wire having an ultimate wire diameter φ of 1.2 mm. In addition, a part was set as a tube which is not subjected to seam welding and has a joint, and the tube was drawn to obtain a flux-cored wire having an ultimate wire diameter φ of 1.2 mm. A composition of the flux-cored wire that was prepared is shown in [Table 1-1] to [Table 1-5], and [Table 2-1] to [Table 2-5].
As shown in FIG. 3, steel plates 1 having a plate thickness of 19 mm were butted to each other with a root gap of 12 mm and a groove angle of 45°, and then welding was performed by using the flux-cored wire and a backing metal 2. The welding was performed with one or two passes at first and second layers and with two or three passes from a third layer to a final layer. The welding was performed under welding conditions shown in [Table 3-1] to [Table 3-5]. In addition, SM490A of JIS G3106 was used as the steel plates 1 and the backing metal 2. The steel plates 1 and the backing metal 2 are used with buttering of two or more layers and of 3 mm or more being performed to a groove face of the steel plates 1 and a surface of the backing metal 2 by using the flux-cored wire that was tested. Here, as the Ti oxide, the Si oxide, the Mg oxide, and the Al oxide, TiO2, SiO2, MgO, Al2O3 were used, respectively. “Metal carbonate” in Tables 1-1 to Table 1-7 represents CaCO3, BaCO3, SrCO3, and MgCO3. Here, the metal carbonate of a wire No. 36 is BaCO3, the metal carbonate of a wire No. 37 is SrCO3, the metal carbonate of a wire No. 51 is MgCO3, and the metal carbonates of the others are CaCO3. “Arc stabilizer” is an oxide or a fluoride of Na and K.
[Table 1-1]
[Table 1-2]
[Table 1-3]
[Table 1-4]
[Table 1-5]
[Table 1-6]
[Table 1-7]
[Table 2-1]
[Table 2-2]
[Table 2-3]
[Table 2-4]
[Table 2-5]
[Table 2-6]
[Table 2-7]
[Table 3-1]
[Table 3-2]
[Table 3-3]
[Table 3-4]
[Table 3-5]
[Table 3-6]
[Table 3-7]
As shown in FIG. 3, a No. Al tensile test specimen (round bar) (diameter=12.5 mm) 5 in accordance with JIS Z 3111 (1986) and a Charpy test specimen (2 mm V-notch) 4 were collected from the weld metal 3 that was obtained, and then respective mechanical characteristic tests were performed to measure the yield strength, the tensile strength, the fracture elongation, the Charpy absorbed energy, and the amount of diffusible hydrogen of the weld metal.
Mechanical characteristic measurement results that were obtained and evaluation results are shown in [Table 4-1] to [Table 4-5].
In addition, in evaluation of mechanical characteristics, a case where the tensile strength was 950 MPa or more, the fracture elongation was 12% or more, and with regard to the toughness, absorbed energy was 27 J or more in the Charpy impact test at 40° C. was regarded as passing.
As shown in the test results shown in [Table 4-1] to [Table 4-5], wire Nos. 1 to 108, which were Examples of the invention, were excellent in all of the strength, the elongation, and the toughness and were regarded as passing.
On the other hand, wire Nos. 109 to 160, which were Comparative Examples, did not satisfy requirements defined in the invention with respect to the flux composition and the alloy composition, and thus the strength, the elongation, and the toughness were not satisfied, or evaluation on the characteristics could not be performed due to inferior welding workability. As a result, all of the wire Nos. 109 to 160 were regarded as failing in the overall determination.
In wire Nos. 127 and 129, the amount of metal fluorides contained in the wire was less than a range of the invention. Therefore, ductility-dip cracking could not be suppressed, the fracture elongation became a low value, and the toughness became a low value. As a result, wire Nos. 127 and 129 were regarded as failing.
In wire Nos. 128 and 130, the amount of metal fluorides contained in the wire was more than the range of the invention. Therefore, arc was unstable and an appearance of a bead was inferior. As a result, evaluation could not be performed, and the wire Nos. 128 and 130 were regarded as failing.
In wire Nos. 124 to 126, 131, and 132, the ratio of the amount of the metal fluoride to the amount of the metal oxide was less than a range of the invention. Therefore, ductility-dip cracking could not be suppressed, and thus the fracture elongation became a low value. As a result, the wire Nos. 124 to 126, 131, and 132 were regarded as failing.
In wire Nos. 133 and 134, the amount of the metal oxide and the iron powder which were contained in the wire were more than the range of the invention. Therefore, the amount of oxygen of the weld metal increased, and thus the toughness decreased. As a result, the wire Nos. 133 and 134 were regarded as failing.
In wire No. 135, the amount of the metal carbonate contained in the wire was more than the range of the invention, and thus weldability and workability were inferior. As a result, the wire No. 135 was regarded as failing.
In wire No. 147, the proportion of CaF2 in the metal fluoride was low, and thus welding workability was inferior. Therefore, evaluation was not performed.
In wire Nos. 109 to 123, 136 to 146, and 148 to 160, the amount of the alloy composition and the metal deoxidizing composition which were contained in the wire deviated from the range of the invention, and any one of the strength, the elongation, and the toughness was not satisfied. As a result, the wire Nos. 109 to 123, 136 to 146, and 148 to 160 were regarded as failing. In addition, in wire No. 147, welding workability and was inferior, and thus evaluation was not performed.
In wire Nos. 109, 110, 115, 116, and 136, the amount of C was less than the range of the invention, and thus the tensile strength became a low value. As a result, the wire Nos. 109, 110, 115, 116, and 136 were regarded as failing. In addition, in wire No. 137, C was more than the range of the invention, and thus the toughness became a low value. As a result, the wire No. 137 was regarded as failing.
In wire No. 138, the amount of Si was less than the range of the invention. Therefore, the amount of oxygen of the weld metal could not be reduced, and thus the toughness decreased. As a result, the wire No. 138 was regarded as failing. In addition, in wire No. 139, the amount of Si was more than the range of the invention, and thus the toughness became a low value. As a result, the wire No. 139 was regarded as failing.
In wire Nos. 111, 112, 122, 123, and 140, the amount of Mn was less than the range of the invention, and thus the fracture elongation became a low value. As a result, the wire Nos. 111, 112, 122, 123, and 140 were regarded as failing. In addition, in wire Nos. 117 to 121, and 141, the amount of Mn was more than the range of the invention, and thus the toughness became a low value. As a result, the wire Nos. 117 to 121, and 141 were regarded as failing.
In wire No. 144, the amount of Al was less than the range of the invention. Therefore, the amount of oxygen of the weld metal could not be reduced, and thus the toughness decreased. As a result, the wire No. 144 was regarded as failing. In addition, in wire No. 145, the amount of Al was more than the range of the invention, and thus the toughness became a low value. As a result, the wire No. 145 was regarded as failing.
In wire No. 146, the amount of Ni was less than the range of the invention, and thus the toughness became a low value. As a result, the wire No. 146 was regarded as failing.
In wire Nos. 113, 114, and 148, the amount of V was less than the range of the invention. Therefore, ductility-dip cracking could not be suppressed, and thus the fracture elongation became a low value. As a result, the wire Nos. 113, 114, and 148 were regarded as failing. In addition, in wire No. 149, the amount of V was more than the range of the invention, and thus the toughness became a low value. As a result, the wire No. 149 was regarded as failing.
In wire No. 142, the amount of P was more than the range of the invention, and thus the fracture elongation and the toughness became a low value. As a result, the wire No. 142 was regarded as failing.
In wire No. 143, the amount of S was more than the range of the invention, and thus the fracture elongation and the toughness became a low value. As a result, the wire No. 143 was regarded as failing.
In wire Nos. 150 to 158, the amount of Cu, Cr, Mo, Ti, Nb, B, Mg, Ca, and REM were more than the range of the invention, and thus the toughness became a low value. As a result, the wire Nos. 150 to 158 were regarded as failing.
In wire No. 159, the value of Ceq was less than the range of the invention, and thus the tensile strength became a low value. As a result, the wire No. 159 was regarded as failing. In addition, in wire No. 160, the value of Ceq was more than the range of the invention, and thus the toughness became a low value. As a result, the wire No. 160 was regarded as failing.
Evaluation was performed in accordance with JIS Z 3111 (2005) with respect to wire Nos. 161 to 175 shown in [Table 1-6] and [Table 2-6]. That is, the evaluation was performed in a manner as shown in FIG. 7 (test plate symbol: 1.3). Steel plates 1 having a plate thickness of 20 mm were butted to each other with a root gap of 16 mm and a groove angle of 20°, and then welding was performed by using a backing metal 2. The welding was performed with one or two passes at first and second layers and with two or three passes from a third layer to a final layer. Welding conditions are shown in [Table 3-6]. In addition, SM490A was used as the steel plates 1 and the backing metal 2. The steel plates 1 and the backing metal 2 are used with buttering of two or more layers and of 3 mm or more being performed to a groove face of the steel plates 1 and a surface of the backing metal 2 by using the flux-cored wire that was tested. As mechanical test specimens, a No. AO tensile test specimen (round bar) (diameter=10 mm) 5 in accordance with JIS Z 3111 (2005) and a Charpy test specimen (2 mm V-notch) 4 were collected. Then, respective mechanical characteristic tests were performed to measure the yield strength, the tensile strength, the fracture elongation, the Charpy absorbed energy, and the amount of diffusible hydrogen of the weld metal. Mechanical characteristic measurement results that were obtained and evaluation results are shown in [Table 4-6].
Wire Nos. 161 to 170, which were Examples of the invention, were excellent in all of the strength, the elongation, and the toughness and were regarded as passing. On the other hand, in wire No. 171 that was Comparative Example, the metal oxide was less than the range of the invention, and thus the appearance of the weld bead 3 was inferior. As a result, the wire No. 171 was regarded as failing. Wire Nos. 172 and 173 were Comparative Examples in which the metal fluoride was less, or the metal fluoride was not contained, but there was less metal fluoride, and thus the diffusible hydrogen was not reduced. Wire No. 174 was Comparative Example of a solid wire, but the diffusible hydrogen was not reduced to a degree of the wire of the invention. Wire No. 175 that was an Example of the invention used a flux in which the amount of CaO as an impurity was large, and thus 0.28% of CaO was contained in terms of mass % with respect to the total mass of the wire. Test results of the wire No. 175 were excellent in all of the strength, the elongation, and the toughness. As a result, the wire No. 175 was regarded as passing.
Wire Nos. 5-2, 6-2, 30-2, 61-2, 62-2, and 90-2 of Examples, which are shown in [Table 1-7] and [Table 2-7] are the same wires as the wire Nos. 5, 6, 30, 61, 62, and 90 of Examples which are shown in [Table 1-1] to [Table 1-3]. Evaluation was performed in accordance with JIS Z 3111 (2005) by using these wires. Welding conditions are shown in [Table 3-7]. Mechanical characteristic measurement results and evaluation results are shown in [Table 4-7]. Similar to the evaluation results in JIS Z 3111 (1986), all of the strength, the elongation, and the toughness were excellent, and the wires was regarded as passing. Accordingly, there is no difference in characteristics due to a difference in an evaluation method between JIS Z 3111-2005 and JIS Z 3111-1986.
With respect to wire Nos. 161 to 175 shown in [Table 1-6] and wire Nos. 5-2, 6-2, 30-2, 61-2, 62-2, and 90-2 shown in [Table 1-7], the amount of CaO in the flux was analyzed.
Measurement of the amount of diffusible hydrogen was performed by gas chromatography in accordance with a method of measuring an amount of diffusible hydrogen of a steel welded part (JIS Z 3118 (2005)). As welding conditions, a current was set to 280 A, a voltage was set to 30 V, and a welding speed was set to 350 mm/min. Results are shown in [Table 4-1] to [Table 4-7]. In any wire, the amount of diffusible hydrogen was 1.0 ml/100 g or less, and thus there was less hydrogen. In the flux-cored wire of the invention, it is considered that the amount of diffusible hydrogen was reduced due to the metal fluoride. Accordingly, the flux-cored wire of the invention is excellent in low-temperature cracking resistance, and thus it is possible to lower a preheating temperature during welding.
In wire Nos. 161 to 164, 166, and 169 of Examples, as shown in Table 3-6, welding was performed without preheating during preparation of a weld joint. In any weld joint, low-temperature cracking was not recognized, and the flux-cored wire of the invention was excellent in the low-temperature cracking resistance.
In addition, an evaluation test on the low-temperature cracking resistance was performed with respect to wire Nos. 161 to 163, 168, 170, and 172 to 175 to evaluate the low-temperature cracking resistance of the wires that were prepared. The evaluation test on the low-temperature cracking resistance was performed in a room capable of constantly managing an atmosphere to be a temperature of 20° C. and humidity of 60% by a method in accordance with JIS Z 3157 (y-groove weld cracking test) under the same welding conditions in Table 3 as the mechanical characteristic test by using TS 1180 MPa steel having a plate thickness of 25 mm. Table 6 shows chemical composition and mechanical characteristics of the steel plate that was used in the y-groove weld cracking test. A critical preheating temperature that was obtained during the y-groove weld cracking test is shown in Table 5. In wire Nos. 172 and 173 in which the amount of metal fluoride was small, the critical preheating temperature was 150° C., and in wire No. 174 that was a solid wire, the critical preheating temperature was 100° C. In contrast, in the wire of the invention, the critical preheating temperature was 50° C. or lower, and it could be seen that the wire of the invention was also excellent in the low-temperature cracking resistance due to reduction of the diffusible hydrogen. The wire of the invention is a flux-cored wire, and thus in the flux that is embedded, a considerable amount of diffusible hydrogen source such as crystallization water is contained. Therefore, the amount of diffusible hydrogen of the weld metal in the wire of the invention further increases in comparison to the solid wire, but exactly contrary results are obtained. In the wire of the invention, the critical preheating temperature is also lower than that of the solid wire. In this manner, the reason why the amount of diffusible hydrogen decreases and thus the t critical preheating temperature is low is considered to be as follows. Fluorine in the fluoride is coupled to hydrogen during welding, and thus the fluorine is discharged to the air as hydrogen fluoride. As a result, the diffusible hydrogen in the weld metal is reduced. That is, when using the wire of the invention, it is possible to further lower the preheating temperature in comparison to a case of using the solid wire.
In addition, in wire No. 175, the amount of CaO was large. Therefore, it is considered that the amount of diffusible hydrogen increased, and thus the low-temperature cracking resistance decreased. From this consideration, it can be seen that it is also preferable to limit the upper limit of the amount of CaO so as to improve the low-temperature cracking resistance.
[Table 4-1]
[Table 4-2]
[Table 4-3]
[Table 4-4]
[Table 4-5]
[Table 4-6]
[Table 4-7]
[Table 5]
[Table 6]
INDUSTRIAL APPLICABILITY
According to the invention, it is possible to provide a flux-cored wire capable of obtaining a weld metal which has high strength and high toughness and which is excellent in elongation by suppressing ductility-dip cracking during the welding of ultrahigh tensile strength steel having a tensile strength of 950 MPa to 1500 MPa.
BRIEF DESCRIPTION OF THE REFERENCE SYMBOLS


    
    
        1: STEEL PLATE
        2: BACKING METAL
        3: WELD BEAD
        4: CHARPY TEST SPECIMEN (2 mm V-NOTCH)
        5: TENSILE TEST SPECIMEN (ROUND BAR)
    
    












TABLE 1-1










CHEIMICAL COMPOSITIN OF FLUX(mass % WITH





RESPECT TO THE TOTAL MASS OF THE WIRE)










METAL FLUORIDE
METAL OXIDE



















WIRE






TOTAL




TOTAL


No.
CATEGORY
REMARKS
CaF2
BaF2
SrF2
MgF2
AMOUNT[α]
TiO2
SiO2
MgO
Al2O3
AMOUNT[β]





1
EXAMPLE

2.1



2.1
0.12
0.24


0.36


2
EXAMPLE

2.5



2.5

0.28

0.08
0.36


3
EXAMPLE

2.9



2.9

0.22


0.22


4
EXAMPLE

3.3



3.3

0.34


0.34


5
EXAMPLE

3.8



3.8

0.42


0.42


6
EXAMPLE

4.2



4.2
0.23
0.56


0.79


7
EXAMPLE
APPLIED
5.0

0.3

5.3
0.12
0.45
0.22

0.79




PFPE※


8
EXAMPLE

5.3



5.3

0.41


0.41


9
EXAMPLE
APPLIED
5.7



5.7
0.54
0.38


0.92




PFPE※


10
EXAMPLE

5.9



5.9

0.34

0.05
0.39


11
EXAMPLE

2.4
0.2


2.6

0.01


0.01


12
EXAMPLE

2.6


0.3
2.9

0.64


0.64


13
EXAMPLE

3.0

0.2

3.2

0.55
0.33

0.88


14
EXAMPLE

3.3


0.2
3.5
0.33
0.68


1.01


15
EXAMPLE
APPLIED
3.5



3.5

0.72


0.72




PFPE※


16
EXAMPLE

3.6



3.6
0.02



0.02


17
EXAMPLE

3.9



3.9
0.12
0.35
0.21

0.68


18
EXAMPLE

6.2
0.1
0.2
0.1
6.6

0.36
0.25

0.61


19
EXAMPLE

7.8



7.8
0.26
0.43


0.69


20
EXAMPLE

6.4
0.4
0.5
0.6
7.9

0.47


0.47


21
EXAMPLE

4.8



4.8
0.25
0.53

0.15
0.93


22
EXAMPLE

5.4



5.4

0.31


0.31


23
EXAMPLE

4.2



4.2


0.03

0.03


24
EXAMPLE
HAVING
3.6



3.6
1.00
0.20


1.20




SEAM


25
EXAMPLE
HAVING
3.4
0.2

0.1
3.7

0.18


0.18




SEAM


26
EXAMPLE

2.9



2.9

0.02


0.02


27
EXAMPLE

2.5
0.2
0.1
0.1
2.9

0.26


0.26


28
EXAMPLE

2.4



2.4
0.73
0.46


1.19


29
EXAMPLE

3.5


0.1
3.6

0.49


0.49


30
EXAMPLE

4.3



4.3

0.50


0.50
















CHEIMICAL COMPOSITIN OF FLUX(mass % WITH






RESPECT TO THE TOTAL MASS OF THE WIRE)

MASS RATIO OF














WIRE
IRON
METAL
ARC
TOTAL AMOUNT[α]/
CaF2 TO METAL



No.
POWDER
CARBONATE
STABILIZER
TOTAL AMOUNT[β]
FLUORIDE(%)







1


0.043
5.8
100



2
0.4

0.005
6.9
100



3


0.002
13.2
100



4


0.032
9.7
100



5


0.048
9.0
100



6


0.045
5.3
100



7


0.027
6.7
94



8

0.58
0.030
12.9
100



9


0.390
6.2
100



10


0.088
15.1
100



11
4.8
0.23
0.076
260.0
92



12
1.2

0.127
4.5
90



13


0.077
3.6
94



14


0.043
3.5
94



15


0.031
4.9
100



16


0.047
180.0
100



17


0.003
5.7
100



18

0.04
0.084
10.8
94



19


0.113
11.3
100



20


0.146
16.8
81



21


0.053
5.2
100



22

0.02
0.046
17.4
100



23


0.042
140.0
100



24


0.046
3.0
100



25


0.037
20.6
92



26
3.2

0.045
145.0
100



27

0.12
0.052
11.2
86



28


0.029
2.0
100



29
0.8

0.024
7.3
97



30


0.032
8.6
100







※PFPE; PERFLUOROPOLYETHER OIL
















TABLE 1-2










CHEIMICAL COMPOSITIN OF FLUX(mass % WITH





RESPECT TO THE TOTAL MASS OF THE WIRE)










METAL FLUORIDE
METAL OXIDE



















WIRE






TOTAL




TOTAL


No.
CATEGORY
REMARKS
CaF2
BaF2
SrF2
MgF2
AMOUNT[α]
TiO2
SiO2
MgO
Al2O3
AMOUNT[β]





31
EXAMPLE

2.3



2.3
0.24
0.22

0.14
0.60


32
EXAMPLE

2.4

0.1

2.5

0.43


0.43


33
EXAMPLE

2.8



2.8

0.46
0.40

0.86


34
EXAMPLE

3.2



3.2
0.13
0.42
0.18

0.73


35
EXAMPLE

3.5



3.5

0.47


0.47


36
EXAMPLE

3.8



3.8

0.53


0.53


37
EXAMPLE

4.2



4.2

0.38
0.52

0.90


38
EXAMPLE

4.5

0.3

4.8

0.36
0.43

0.79


39
EXAMPLE
APPLIED
2.2
0.3


2.5

0.42


0.42




PFPE※


40
EXAMPLE

2.4



2.4

0.46


0.46


41
EXAMPLE

5.9


0.1
6.0

0.52
0.23

0.75


42
EXAMPLE

6.1



6.1

0.84


0.84


43
EXAMPLE

7.2



7.2
0.22
0.46


0.68


44
EXAMPLE

7.9



7.9

0.21


0.21


45
EXAMPLE

3.2



3.2

0.03


0.03


46
EXAMPLE

3.6



3.6

0.02


0.02


47
EXAMPLE

3.4
0.8


4.2

0.02


0.02


48
EXAMPLE

4.2
0.1


4.3
0.15



0.15


49
EXAMPLE

4.6

0.3
0.2
5.1



0.03
0.03


50
EXAMPLE

4.8



4.8
0.23
0.23


0.46


51
EXAMPLE
APPLIED
2.9



2.9
0.16
0.43


0.59




PFPE※


52
EXAMPLE

3.3
0.1
0.1
0.2
3.7
0.25
0.42


0.67


53
EXAMPLE

3.5



3.5

0.34
0.24

0.58


54
EXAMPLE

3.9



3.9
0.48
0.28


0.76


55
EXAMPLE

4.3



4.3

0.56


0.56


56
EXAMPLE

4.0
0.2


4.2
0.72
0.42


1.14


57
EXAMPLE
HAVING
3.6


0.2
3.8

0.13


0.13




SEAM


58
EXAMPLE
HAVING
3.5


0.3
3.8

0.25

0.18
0.43




SEAM


59
EXAMPLE

3.3


0.8
4.1
0.12
0.40
0.10
0.05
0.67


60
EXAMPLE

4.1



4.1
0.22
0.37
0.11

0.70
















CHEIMICAL COMPOSITIN OF FLUX(mass % WITH






RESPECT TO THE TOTAL MASS OF THE WIRE)

MASS RATIO OF














WIRE
IRON
METAL
ARC
TOTAL AMOUNT[α]/
CaF2 TO METAL



No.
POWDER
CARBONATE
STABILIZER
TOTAL AMOUNT[β]
FLUORIDE(%)







31


0.023
3.8
100



32
0.5

0.024
5.8
96



33
0.8

0.024
3.3
100



34


0.046
4.4
100



35


0.004
7.4
100



36

0.05
0.024
7.2
100



37
0.7
0.02
0.002
4.7
100



38


0.020
6.1
94



39


0.087
6.0
88



40


0.008
5.2
100



41


0.018
8.0
98



42

0.18
0.023
7.3
100



43


0.026
10.6
100



44


0.033
37.6
100



45
1.4

0.042
106.7
100



46
0.8

0.048
180.0
100



47

0.22
0.052
210.0
81



48


0.028
28.7
98



49


0.016
170.0
90



50

0.16
0.005
10.4
100



51
0.6
0.04
0.008
4.9
100



52
0.4

0.035
5.5
89



53
1.2

0.037
6.0
100



54


0.047
5.1
100



55


0.046
7.7
100



56


0.006
3.7
95



57
0.9

0.005
29.2
95



58


0.008
8.8
92



59


0.024
6.1
80



60
0.5

0.047
5.9
100







※PFPE; PERFLUOROPOLYETHER OIL
















TABLE 1-3










CHEIMICAL COMPOSITIN OF FLUX(mass % WITH





RESPECT TO THE TOTAL MASS OF THE WIRE)










METAL FLUORIDE
METAL OXIDE



















WIRE






TOTAL




TOTAL


No.
CATEGORY
REMARKS
CaF2
BaF2
SrF2
MgF2
AMOUNT[α]
TiO2
SiO2
MgO
Al2O3
AMOUNT[β]





61
EXAMPLE

3.2



3.2

0.30


0.30


62
EXAMPLE

3.6



3.6
0.10
0.25


0.35


63
EXAMPLE

4.2



4.2
0.15
0.24
0.12

0.51


64
EXAMPLE

4.5



4.5
0.21
0.32
0.15
0.03
0.71


65
EXAMPLE
APPLIED
3.4
0.2


3.6
0.23
0.43


0.66




PFPE※


66
EXAMPLE
APPLIED
3.8

0.3

4.1

0.44


0.44




PFPE※


67
EXAMPLE
APPLIED
4.3



4.3
0.25
0.28
0.20

0.73




PFPE※


68
EXAMPLE

4.8



4.8

0.43


0.43


69
EXAMPLE

5.3



5.3



0.08
0.08


70
EXAMPLE

3.4



3.4

0.24


0.24


71
EXAMPLE

3.6

0.1
0.3
4.0
0.28
0.18
0.08

0.54


72
EXAMPLE

3.9



3.9

0.35


0.35


73
EXAMPLE

4.3



4.3
0.10
0.28
0.13

0.51


74
EXAMPLE

4.4



4.4
0.20
0.45
0.19

0.84


75
EXAMPLE

3.8



3.8

0.46


0.46


76
EXAMPLE

3.6



3.6

0.55


0.55


77
EXAMPLE

4.6



4.6

0.63


0.63


78
EXAMPLE

3.4



3.4
0.40
0.35


0.75


79
EXAMPLE

3.6



3.6
0.18
0.48


0.66


80
EXAMPLE

4.2


0.3
4.5

0.34
0.20

0.54


81
EXAMPLE

4.0



4.0

0.46


0.46


82
EXAMPLE

3.2



3.2

0.35

0.04
0.39


83
EXAMPLE

3.4



3.4
0.20



0.20


84
EXAMPLE

3.8



3.8
0.14
0.22
0.18

0.54


85
EXAMPLE

4.2
0.1

0.1
4.4

0.36

0.14
0.50


86
EXAMPLE

4.9
0.2


5.1

0.46


0.46


87
EXAMPLE
HAVING
5.5



5.5

0.42


0.42




SEAM


88
EXAMPLE
HAVING
4.6



4.6

0.45


0.45




SEAM


89
EXAMPLE

3.2



3.2
0.18
0.38
0.15

0.71


90
EXAMPLE

3.6



3.6
0.20
0.26

0.23
0.69
















CHEIMICAL COMPOSITIN OF FLUX(mass % WITH






RESPECT TO THE TOTAL MASS OF THE WIRE)

MASS RATIO OF














WIRE
IRON
METAL
ARC
TOTAL AMOUNT[α]/
CaF2 TO METAL



No.
POWER
CARBONATE
STABILIZER
TOTAL AMOUNT[β]
FLUORIDE(%)







61


0.042
10.7
100



62


0.035
10.3
100



63


0.036
8.2
100



64


0.024
6.3
100



65


0.026
5.5
94



66


0.012
9.3
93



67


0.028
5.9
100



68


0.036
11.2
100



69


0.046
66.3
100



70


0.048
14.2
100



71


0.056
7.4
90



72


0.032
11.1
100



73


0.031
8.4
100



74


0.003
5.2
100



75

0.22
0.043
8.3
100



76


0.040
6.5
100



77


0.028
7.3
100



78


0.018
4.5
100



79


0.026
5.5
100



80


0.033
8.3
93



81


0.028
8.7
100



82
1.4

0.046
8.2
100



83


0.042
17.0
100



84


0.040
7.0
100



85


0.039
8.8
95



86


0.036
11.1
96



87


0.044
13.1
100



88


0.041
10.2
100



89


0.038
4.5
100



90


0.035
5.2
100







※PFPE; PERFLUOROPOLYETHER OIL
















TABLE 1-4










CHEIMICAL COMPOSITIN OF FLUX(mass % WITH





RESPECT TO THE TOTAL MASS OF THE WIRE)










METAL FLUORIDE
METAL OXIDE



















WIRE






TOTAL




TOTAL


No.
CATEGORY
REMARKS
CaF2
BaF2
SrF2
MgF2
AMOUNT[α]
TiO2
SiO2
MgO
Al2O3
AMOUNT[β]





91
EXAMPLE

3.2



3.2
0.20
0.25


0.45


92
EXAMPLE

2.8



2.8

0.24


0.24


93
EXAMPLE
APPLIED
5.9
0.2


6.1
0.13
0.18


0.31




PFPE※


94
EXAMPLE
APPLIED
5.6

0.3

5.9
0.12

0.28

0.40




PFPE※


95
EXAMPLE

2.9



2.9
0.18
0.24
0.22

0.64


96
EXAMPLE

3.0


0.2
3.2

0.34


0.34


97
EXAMPLE

3.4



3.4

0.33

0.16
0.49


98
EXAMPLE

3.2



3.2

0.28
0.18
0.21
0.67


99
EXAMPLE

4.8

0.2

5.0
0.24
0.38


0.62


100
EXAMPLE

4.4


0.1
4.5
0.18
0.21
0.19

0.58


101
EXAMPLE

2.2



2.2
0.35
0.43
0.26

1.04


102
EXAMPLE

2.4



2.4
0.48
0.45
0.24

1.17


103
EXAMPLE

2.6
0.1

0.1
2.8
0.35
0.34

0.18
0.87


104
EXAMPLE

2.7

0.1

2.8
0.23
0.30
0.24

0.77


105
EXAMPLE

3.2



3.2

0.36


0.36


106
EXAMPLE

3.5
0.2

0.1
3.8
0.24
0.26
0.22

0.72


107
EXAMPLE

3.7



3.7
0.18
0.25


0.43


108
EXAMPLE

4.0

0.3

4.3
0.23
0.24

0.15
0.62


109
COMPARATIVE

3.6
0.2


3.8

0.43


0.43



EXAMPLE


110
COMPARATIVE

2.4



2.4

0.38


0.38



EXAMPLE


111
COMPARATIVE

3.5



3.5

0.42
0.23

0.65



EXAMPLE


112
COMPARATIVE

2.8



2.8

0.34


0.34



EXAMPLE


113
COMPARATIVE

3.6
0.3


3.9
0.20
0.28


0.48



EXAMPLE


114
COMPARATIVE

4.6



4.6
0.12
0.20
0.15

0.47



EXAMPLE


115
COMPARATIVE

2.7

0.2
0.1
3.0

0.32


0.32



EXAMPLE


116
COMPARATIVE
APPLIED
3.0

0.3
0.2
3.5
0.16
0.18


0.34



EXAMPLE
PFPE※


117
COMPARATIVE

2.1
0.1

0.1
2.3

0.22
0.18

0.40



EXAMPLE


118
COMPARATIVE

3.6



3.6
0.16

0.32
0.11
0.59



EXAMPLE


119
COMPARATIVE
APPLIED
3.2



3.2
0.24
0.19

0.13
0.56



EXAMPLE
PFPE※


120
COMPARATIVE

3.4
0.2


3.6
0.32
0.38


0.70



EXAMPLE


121
COMPARATIVE

3.8



3.8
0.31
0.42
0.15

0.88



EXAMPLE


122
COMPARATIVE

2.2

0.1

2.3
0.37
0.39
0.20

0.96



EXAMPLE


123
COMPARATIVE

2.3



2.3
0.36
0.28


0.64



EXAMPLE


124
COMPARATIVE

2.1



2.1
0.48
0.45
0.25

1.18



EXAMPLE


125
COMPARATIVE
APPLIED
2.3



2.3
0.55
0.42

0.23
1.20



EXAMPLE
PFPE※


126
COMPARATIVE

2.0
0.1


2.1
0.37
0.39
0.42

1.18



EXAMPLE
















CHEIMICAL COMPOSITIN OF FLUX(mass % WITH






RESPECT TO THE TOTAL MASS OF THE WIRE)

MASS RATIO OF














WIRE
IRON
METAL
ARC
TOTAL AMOUNT[α]/
CaF2 TO METAL



No.
POWDER
CARBONATE
STABILIZER
TOTAL AMOUNT[β]
FLUORIDE(%)







91


0.043
7.1
100



92


0.028
11.7
100



93

0.25
0.043
19.7
97



94

0.12
0.036
14.8
95



95


0.002
4.5
100



96
0.5

0.024
9.4
94



97


0.046
6.9
100



98


0.002
4.8
100



99
0.8

0.035
8.1
96



100


0.056
7.8
98



101
1.5

0.048
2.1
100



102

0.15
0.003
2.1
100



103


0.046
3.2
93



104
1.2
0.10
0.068
3.6
96



105


0.056
8.9
100



106


0.054
5.3
92



107


0.005
8.6
100



108


0.068
6.9
93



109

0.21
0.035
8.8
95



110


0.034
6.3
100



111
0.6

0.020
5.4
100



112


0.026
8.2
100



113


0.024
8.1
92



114


0.036
9.8
100



115


0.048
9.4
90



116


0.064
10.3
86



117


0.055
5.8
91



118


0.032
6.1
100



119


0.015
5.7
100



120


0.013
5.1
94



121


0.026
4.3
100



122


0.034
2.4
96



123


0.027
3.6
100



124


0.025
1.8
100



125


0.026
1.9
100



126


0.035
1.8
95







※PFPE; PERFLUOROPOLYETHER OIL
















TABLE 1-5










CHEIMICAL COMPOSITIN OF FLUX(mass % WITH





RESPECT TO THE TOTAL MASS OF THE WIRE)










METAL FLUORIDE











WIRE

TOTAL
METAL OXIDE


















No.
CATEGORY
REMARKS
CaF2
BaF2
SrF2
MgF2
AMOUNT[α]
TiO2
SiO2
MgO
Al2O3





127
COMPARATIVE

1.9



1.9

0.26



EXAMPLE


128
COMPARATIVE

8.2



8.2

0.32

0.05



EXAMPLE


129
COMPARATIVE

1.5
0.2
0.1
0.1
1.9
0.21
0.46

0.10



EXAMPLE


130
COMPARATIVE
APPLIED
6.5
1.0
0.3
0.3
8.1

0.42



EXAMPLE
PFPE※


131
COMPARATIVE
APPLIED
2.1



2.1
0.78
0.42



EXAMPLE
PFPE※


132
COMPARATIVE

1.6
0.2
0.1
0.2
2.1
0.62
0.56



EXAMPLE


133
COMPARATIVE

4.2



4.2
1.05
0.40



EXAMPLE


134
COMPARATIVE

2.4



2.4
0.32

0.22



EXAMPLE


135
COMPARATIVE

3.8



3.8

0.24

0.21



EXAMPLE


136
COMPARATIVE

2.8



2.8

0.25



EXAMPLE


137
COMPARATIVE

3.2



3.2


0.23
0.24



EXAMPLE


138
COMPARATIVE

3.1



3.1

0.42



EXAMPLE


139
COMPARATIVE

2.8

0.2

3.0

0.46
0.21
0.22



EXAMPLE


140
COMPARATIVE

3.2

0.2

3.4


0.05



EXAMPLE


141
COMPARATIVE

3.5



3.5

0.43



EXAMPLE


142
COMPARATIVE

3.2



3.2

0.40
0.21



EXAMPLE


143
COMPARATIVE

3.2
0.3


3.5

0.38



EXAMPLE


144
COMPARATIVE

2.8
0.1

0.2
3.1

0.42

0.18



EXAMPLE


145
COMPARATIVE
APPLIED
2.9



2.9
0.15



EXAMPLE
PFPE※


146
COMPARATIVE
APPLIED
3.8



3.8

0.54



EXAMPLE
PFPE※


147
COMPARATIVE

1.0
0.5
0.3
0.3
2.1

0.22



EXAMPLE


148
COMPARATIVE

3.4
0.3
0.2

3.9

0.53



EXAMPLE


149
COMPARATIVE

3.2



3.2


0.12



EXAMPLE


150
COMPARATIVE

2.9
0.3

0.2
3.4

0.32



EXAMPLE


151
COMPARATIVE

2.9

0.2
0.2
3.3

0.27
0.36



EXAMPLE


152
COMPARATIVE

3.1



3.1

0.08



EXAMPLE


153
COMPARATIVE

3.3



3.3

0.42

0.32



EXAMPLE


154
COMPARATIVE

3.2



3.2
0.22
0.43



EXAMPLE


155
COMPARATIVE

3.5

0.2

3.7

0.34

0.11



EXAMPLE


156
COMPARATIVE

3.5
0.3


3.8

0.36



EXAMPLE


157
COMPARATIVE

3.2



3.2
0.12
0.46



EXAMPLE


158
COMPARATIVE

3.6



3.6

0.35



EXAMPLE


159
COMPARATIVE

3.5



3.5

0.36



EXAMPLE


160
COMPARATIVE

3.2



3.2

0.42
0.18



EXAMPLE













CHEIMICAL COMPOSITIN OF FLUX(mass % WITH




RESPECT TO THE TOTAL MASS OF THE WIRE)














METAL








OXIDE




MASS RATIO OF


WIRE
TOTAL
IRON
METAL
ARC
TOTAL AMOUNT[α]/
CaF2 TO METAL


No.
AMOUNT[β]
POWDER
CARBONATE
STABILIZER
TOTAL AMOUNT[β]
FLUORIDE(%)





127
0.26


0.040
7.3
100


128
0.37


0.036
22.2
100


129
0.77


0.042
2.5
79


130
0.42


0.026
19.3
80


131
1.20


0.028
1.8
100


132
1.18


0.033
1.8
76


133
1.45


0.036
2.9
100


134
0.54
5.8

0.008
4.4
100


135
0.45

0.62
0.016
8.4
100


136
0.25


0.026
11.2
100


137
0.47


0.025
6.8
100


138
0.42


0.028
7.4
100


139
0.89

0.24
0.046
3.4
93


140
0.05

0.18
0.048
68.0
94


141
0.43
1.5

0.055
8.1
100


142
0.61

0.08
0.052
5.2
100


143
0.38
1.7
0.12
0.049
9.2
91


144
0.60


0.054
5.2
90


145
0.15


0.046
19.3
100


146
0.54


0.046
7.0
100


147
0.22


0.024
9.5
48


148
0.53


0.028
7.4
87


149
0.12
1.2

0.026
26.7
100


150
0.32


0.036
10.6
85


151
0.63


0.037
5.2
88


152
0.08
0.8

0.032
38.8
100


153
0.74
0.5

0.036
4.5
100


154
0.65


0.035
4.9
100


155
0.45

0.18
0.032
8.2
95


156
0.36

0.15
0.036
10.6
92


157
0.58


0.035
5.5
100


158
0.35


0.042
10.3
100


159
0.36


0.046
9.7
100


160
0.60


0.050
5.3
100





※PFPE; PERFLUOROPOLYETHER OIL
















TABLE 1-6










CHEIMICAL COMPOSITIN OF FLUX(mass % WITH





RESPECT TO THE TOTAL MASS OF THE WIRE)










METAL FLUORIDE
METAL OXIDE



















WIRE






TOTAL




TOTAL


No.
CATEGORY
REMARKS
CaF2
BaF2
SrF2
MgF2
AMOUNT[α]
TiO2
SiO2
MgO
Al2O3
AMOUNT[β]





161
EXAMPLE

4.2



4.2
0.23
0.34


0.57


162
EXAMPLE
APPLIED
5.8

0.1

5.9

0.15
0.23

0.38




PFPE※


163
EXAMPLE

2.8


0.2
3.0
0.08
0.12

0.08
0.28


164
EXAMPLE

3.8



3.8
0.11
0.44


0.55


165
EXAMPLE

4.0
0.2


4.2

0.69

0.20
0.89


166
EXAMPLE

4.5



4.5

0.77
0.21

0.98


167
EXAMPLE

3.7


0.1
3.8
0.06
0.45


0.51


168
EXAMPLE

4.2



4.2

0.40

0.16
0.56


169
EXAMPLE
APPLIED
3.1



3.1
0.12
0.43
0.23

0.78




PFPE※


170
EXAMPLE
HAVING
4.8



4.8
0.15
0.35


0.50




SEAM


171
COMPARATIVE

4.5
0.2
0.1

4.8




0.00



EXAMPLE


172
COMPARATIVE

1.1



1.1
0.12
0.40


0.52



EXAMPLE


173
COMPARATIVE





0.0

0.48


0.48



EXAMPLE


174
COMPARATIVE
SOLID
—
—
—
—
—
—
—
—
—
—



EXAMPLE
WIRE


175
EXAMPLE

2.8



2.8
0.22
0.32


0.54

















CHEIMICAL COMPOSITIN OF FLUX(mass % WITH







RESPECT TO THE TOTAL MASS OF THE WIRE)

MASS RATIO OF















WIRE
IRON
METAL
ARC
TOTAL AMOUNT[α]/
CaF2 TO METAL
CaO



No.
POWDER
CARBONATE
STABILIZER
TOTAL AMOUNT[β]
FLUORIDE(%)
[mass %]







161


0.082
7.4
100
0.08



162

0.15
0.045
15.5 
98
<0.03



163


0.026
10.7 
93
<0.03



164


0.058
6.9
100
0.05



165


0.086
4.7
95
0.15



166


0.124
4.6
100
<0.03



167


0.061
7.5
97
0.04



168



7.5
100
0.12



169



4.0
100
0.03



170


0.032
9.6
100
<0.03



171


0.026
—
94
<0.03



172



2.1
100
<0.03



173



0.0
—
0.04



174
—
—
—
—
—
<0.03



175


0.025
5.2
100
0.28







※PFPE; PERFLUOROPOLYETHER OIL
















TABLE 1-7










CHEIMICAL COMPOSITIN OF FLUX(mass % WITH





RESPECT TO THE TOTAL MASS OF THE WIRE)










METAL FLUORIDE
METAL OXIDE



















WIRE






TOTAL




TOTAL


No.
CATEGORY
REMARKS
CaF2
BaF2
SrF2
MgF2
AMOUNT[α]
TiO2
SiO2
MgO
Al2O3
AMOUNT[β]





 5-2
EXAMPLE

3.8



3.8

0.42


0.42


 6-2
EXAMPLE

4.2



4.2
0.23
0.56


0.79


30-2
EXAMPLE

4.3



4.3

0.50


0.50


61-2
EXAMPLE

3.2



3.2

0.30


0.30


62-2
EXAMPLE

3.6



3.6
0.10
0.25


0.35


90-2
EXAMPLE

3.6



3.6
0.20
0.26

0.23
0.69

















CHEIMICAL COMPOSITIN OF FLUX(mass % WITH







RESPECT TO THE TOTAL MASS OF THE WIRE)

MASS RATIO OF















WIRE
IRON
METAL
ARC
TOTAL AMOUNT[α]/
CaF2 TO METAL
CaO



No.
POWDER
CARBONATE
STABILIZER
TOTAL AMOUNT[β]
FLUORIDE(%)
[mass %]







 5-2


0.048
9.0
100
<0.03



 6-2


0.045
5.3
100
0.10



30-2


0.032
8.6
100
<0.03



61-2


0.042
10.7
100
0.06



62-2


0.035
10.3
100
0.08



90-2


0.035
5.2
100
<0.03







※PFPE; PERFLUOROPOLYETHER OIL















TABLE 2-1







WIRE

CHEMICAL COMPOSITION OF WIRE [mass % WITH RESPECT TO TOTAL MASS OF WIRE]


























No.
CATEGORY
C
Si
Mn
P
S
Al
Ni
V
Cu
Cr
Mo
Ti
Nb
B
Mg
Ca
REM
Ceq





























1
EXAMPLE
0.081
0.26
1.8
0.012
0.005
0.002
8.2
0.06









0.60


2
EXAMPLE
0.093
0.42
1.6
0.012
0.006
0.004
1.8
0.18
0.22
0.8
0.5
0.018
0.02
0.0004
0.2
0.1
0.0020
0.72


3
EXAMPLE
0.094
0.64
1.7
0.010
0.005
0.003
2.6
0.06
0.20
0.5
0.4



0.1


0.67


4
EXAMPLE
0.144
0.48
2.2
0.008
0.004
0.003
2.8
0.08









0.61


5
EXAMPLE
0.102
0.46
1.8
0.008
0.003
0.005
2.4
0.08
0.23
0.8
0.8






0.85


6
EXAMPLE
0.103
0.38
1.2
0.009
0.005
0.002
2.6
0.09
0.18
1.2
0.6
0.017

0.0042


0.0012
0.78


7
EXAMPLE
0.107
0.43
1.6
0.014
0.002
0.004
2.8
0.12
0.15
0.5
0.5

0.02
0.0043
0.3


0.70


8
EXAMPLE
0.105
0.40
1.4
0.012
0.006
0.003
2.5
0.24
0.18
1.2
0.4

0.01

0.2


0.77


9
EXAMPLE
0.113
0.05
1.8
0.008
0.008
0.004
2.4
0.22
0.22
2.0





0.2

0.89


10
EXAMPLE
0.111
0.08
1.6
0.009
0.005
0.002
3.2
0.16


0.8

0.05
0.0056
0.2
0.3

0.67


11
EXAMPLE
0.127
0.35
1.0
0.011
0.006
0.003
3.3
0.29
0.16
0.8
0.2


0.0054



0.62


12
EXAMPLE
0.116
0.42
1.5
0.007
0.005
0.004
2.8
0.25
0.33
0.5
0.3
0.024


0.4


0.65


13
EXAMPLE
0.115
0.52
1.8
0.009
0.012
0.012
2.6
0.18
0.24
1.2
0.6
0.022
0.03

0.4

0.0084
0.90


14
EXAMPLE
0.122
0.58
1.7
0.015
0.011
0.014
2.7
0.16
0.23

0.6






0.66


15
EXAMPLE
0.126
0.56
1.7
0.016
0.008
0.016
5.8
0.19
0.20

0.4


0.0098
0.2


0.69


16
EXAMPLE
0.114
0.52
1.8
0.019
0.004
0.006
5.4
0.22
0.44

0.8
0.297





0.79


17
EXAMPLE
0.118
0.84
2.1
0.014
0.006
0.008
5.3
0.14
0.79

0.6
0.105
0.02




0.80


18
EXAMPLE
0.128
1.48
1.6
0.012
0.005
0.002
2.8
0.12
0.23

1.2


0.0051
0.5


0.83


19
EXAMPLE
0.136
0.84
2.2
0.009
0.005
0.003
2.2
0.13
0.21








0.60


20
EXAMPLE
0.134
0.56
2.2
0.008
0.008
0.002
2.6
0.20









0.60


21
EXAMPLE
0.133
0.48
1.8
0.008
0.006
0.396
5.6
0.20
0.18
0.5
0.3






0.78


22
EXAMPLE
0.125
0.55
1.5
0.007
0.005
0.323
5.2
0.12
0.42
0.3
0.5
0.016


0.8

0.0021
0.72


23
EXAMPLE
0.116
0.50
1.8
0.009
0.004
0.286
2.7
0.14
0.30
0.5

0.032
0.02

0.6
0.2

0.61


24
EXAMPLE
0.119
0.46
1.6
0.011
0.006
0.184
2.6
0.08

1.5



0.0023

0.4

0.78


25
EXAMPLE
0.116
0.22
1.6
0.012
0.002
0.143
2.2
0.07


2.0


0.0015
0.6


0.95


26
EXAMPLE
0.126
0.20
1.8
0.011
0.008
0.086
1.8
0.052
0.24
1.2


0.01


0.5

0.72


27
EXAMPLE
0.120
0.32
2.1
0.013
0.005
0.043
1.5
0.08
0.20
1.6
0.1
0.035





0.87


28
EXAMPLE
0.122
0.47
2.2
0.008
0.006
0.056
1.8
0.07
0.35
0.5
0.3
0.028

0.0012
0.4


0.73


29
EXAMPLE
0.117
0.37
1.6
0.009
0.004
0.062
3.2
0.12
0.22
0.6




0.3
0.2

0.61


30
EXAMPLE
0.126
0.33
1.5
0.010
0.005
0.047
2.9
0.18
0.28
2.5







0.98


















TABLE 2-2







WIRE

CHEMICAL COMPOSITION OF WIRE [mass % WITH RESPECT TO TOTAL MASS OF WIRE]


























No.
CATEGORY
C
Si
Mn
P
S
Al
Ni
V
Cu
Cr
Mo
Ti
Nb
B
Mg
Ca
REM
Ceq





























31
EXAMPLE
0.082
0.87
2.2
0.008
0.006
0.008
1.8
0.06
0.21
0.5
0.3
0.015
0.02
0.0004
0.4
0.2
0.0023
0.71


32
EXAMPLE
0.088
0.63
2.1
0.011
0.004
0.002
5.3
0.13
0.26








0.61


33
EXAMPLE
0.093
0.43
1.8
0.010
0.005
0.003
3.8
0.08
0.17
0.6
0.5
0.016


0.2


0.76


34
EXAMPLE
0.097
0.52
2.1
0.009
0.005
0.005
2.7
0.09


0.6

0.02




0.69


35
EXAMPLE
0.101
0.24
1.9
0.012
0.006
0.367
2.2
0.06
0.23
0.8
0.3






0.72


36
EXAMPLE
0.105
0.53
1.8
0.013
0.008
0.004
2.9
0.051
0.21
1.0
0.8
0.026

0.0005



0.90


37
EXAMPLE
0.114
0.42
1.6
0.007
0.005
0.013
3.2
0.056
0.28
1.2
0.7
0.028
0.01

0.3

0.0014
0.90


38
EXAMPLE
0.118
0.32
1.6
0.006
0.006
0.184
2.6
0.09
0.19
0.8
0.9



0.2


0.85


39
EXAMPLE
0.126
0.33
2.1
0.009
0.003
0.043
8.9
0.07
0.22








0.72


40
EXAMPLE
0.198
0.36
1.1
0.012
0.002
0.052
7.8
0.11
0.34
1.0





0.3

0.80


41
EXAMPLE
0.178
0.42
1.2
0.011
0.005
0.061
2.5
0.06
0.23
2.4

0.036





0.94


42
EXAMPLE
0.157
0.44
1.6
0.014
0.003
0.064
6.2
0.08
0.21
0.8
0.4
0.034
0.03

0.4


0.86


43
EXAMPLE
0.139
0.41
1.8
0.010
0.002
0.046
3.2
0.14
0.36

1.5



0.3

0.0087
0.92


44
EXAMPLE
0.134
0.56
1.3
0.009
0.006
0.052
1.5
0.15
0.18
0.8
0.5






0.71


45
EXAMPLE
0.131
0.55
1.6
0.008
0.004
0.053
2.6
0.15

0.8
0.6


0.0023



0.81


46
EXAMPLE
0.124
0.39
1.8
0.011
0.002
0.028
3.6
0.18
0.20

1.2

0.05


0.3

0.84


47
EXAMPLE
0.126
0.21
2.0
0.008
0.006
0.015
4.2
0.22
0.27

0.5
0.286





0.71


48
EXAMPLE
0.136
0.06
1.2
0.013
0.008
0.013
1.8
0.23
0.63
1.8







0.76


49
EXAMPLE
0.133
0.08
1.8
0.012
0.002
0.016
1.6
0.16
0.24
0.5
0.8





0.0018
0.79


50
EXAMPLE
0.132
0.11
1.7
0.010
0.003
0.018
3.1
0.18
0.17

0.6
0.199

0.0048



0.66


51
EXAMPLE
0.127
0.16
2.0
0.008
0.006
0.012
3.5
0.21
0.25

0.6

0.02
0.0042
0.5


0.72


52
EXAMPLE
0.123
0.21
2.0
0.009
0.010
0.011
3.7
0.23
0.22
0.8
0.2

0.03

0.4


0.78


53
EXAMPLE
0.120
0.26
1.8
0.012
0.011
0.007
2.8
0.20
0.47
0.5
1.0
0.024





0.87


54
EXAMPLE
0.134
0.50
1.3
0.008
0.005
0.006
2.7
0.17
0.21
0.8
1.8






1.06


55
EXAMPLE
0.139
1.45
1.0
0.009
0.006
0.005
3.3
0.15
0.29

1.0
0.013

0.0006



0.71


56
EXAMPLE
0.135
0.12
1.4
0.011
0.004
0.006
3.4
0.16
0.18
1.2

0.016
0.04
0.0021

0.5

0.71


57
EXAMPLE
0.127
0.22
1.8
0.009
0.005
0.004
4.3
0.15

0.8
1.9

0.02

0.8


1.19


58
EXAMPLE
0.129
0.37
1.9
0.009
0.006
0.003
2.9
0.18

1.0
0.3





0.0020
0.82


59
EXAMPLE
0.122
0.92
2.1
0.010
0.003
0.004
2.8
0.16
0.22

1.5
0.029





0.97


60
EXAMPLE
0.126
0.52
1.6
0.012
0.008
0.006
3.3
0.19
0.38
0.4
1.2






0.89


















TABLE 2-3







WIRE

CHEMICAL COMPOSTION OF WIRE [mass % WITH RESPECT TO TOTAL MASS OF WIRE]


























No.
CATEGORY
C
Si
Mn
P
S
Al
Ni
V
Cu
Cr
Mo
Ti
Nb
B
Mg
Ca
REM
Ceq





























61
EXAMPLE
0.111
0.80
1.4
0.010
0.008
0.003
3.5
0.16
0.25
0.8
0.5



0.4


0.76


62
EXAMPLE
0.139
0.45
1.8
0.008
0.007
0.025
5.6
0.23
0.90








0.61


63
EXAMPLE
0.126
0.41
1.5
0.008
0.006
0.012
2.2
0.14
0.24
0.6
0.5
0.021





0.70


64
EXAMPLE
0.116
0.43
1.5
0.006
0.004
0.023
2.4
0.16
0.22
1.0
0.4



0.4


0.76


65
EXAMPLE
0.115
0.52
1.8
0.008
0.003
0.013
2.1
0.21
0.18
0.8
0.4






0.76


66
EXAMPLE
0.123
0.53
1.5
0.010
0.005
0.015
2.6
0.15
0.24
0.6
0.8



0.3


0.79


67
EXAMPLE
0.114
0.41
1.8
0.008
0.005
0.005
2.5
0.16
0.28
0.5
0.4
0.015


0.5
0.2

0.71


68
EXAMPLE
0.112
0.43
1.7
0.008
0.003
0.006
2.4
0.18
0.20
0.8
0.5
0.048


0.5


0.77


69
EXAMPLE
0.118
0.53
1.6
0.008
0.006
0.005
2.8
0.23
0.34
0.8


0.02




0.65


70
EXAMPLE
0.116
0.32
1.2
0.009
0.005
0.003
3.3
0.22
0.31

1.2




0.4

0.73


71
EXAMPLE
0.124
0.43
1.6
0.010
0.006
0.006
3.2
0.17
0.37
0.4
0.5


0.0026
0.4


0.71


72
EXAMPLE
0.120
0.46
2.0
0.007
0.004
0.008
3.8
0.18
0.31
1.2
0.4



0.4

0.0034
0.92


73
EXAMPLE
0.126
0.48
1.5
0.006
0.005
0.005
3.9
0.15
0.35
1.0


0.04

0.3


0.70


74
EXAMPLE
0.136
0.46
1.2
0.005
0.006
0.006
4.6
0.12
0.18

1.4






0.83


75
EXAMPLE
0.134
0.56
1.6
0.008
0.004
0.045
4.8
0.13
0.20

1.2
0.016




0.0019
0.85


76
EXAMPLE
0.135
0.68
1.5
0.008
0.005
0.078
5.4
0.15
0.17
1.4




0.5


0.84


77
EXAMPLE
0.115
0.78
1.8
0.005
0.006
0.056
5.2
0.12
0.19

0.8



0.5


0.79


78
EXAMPLE
0.116
0.65
1.8
0.007
0.006
0.026
5.8
0.16
0.24

0.5


0.0029



0.72


79
EXAMPLE
0.119
0.63
1.5
0.006
0.004
0.012
2.8
0.18

1.0
0.5



0.4


0.80


80
EXAMPLE
0.125
0.56
1.6
0.006
0.006
0.015
3.6
0.22
0.24
0.8
0.6



0.4


0.83


81
EXAMPLE
0.126
0.45
1.5
0.008
0.006
0.012
3.4
0.20
0.31
0.7
0.3



0.6


0.71


82
EXAMPLE
0.124
0.48
1.6
0.008
0.005
0.032
2.0
0.14
0.24
0.6
0.5
0.025





0.72


83
EXAMPLE
0.123
0.40
1.8
0.006
0.008
0.008
1.9
0.12
0.23

0.8



0.4


0.70


84
EXAMPLE
0.126
0.56
1.8
0.008
0.004
0.015
1.6
0.16
0.27
0.5
0.5



0.3


0.73


85
EXAMPLE
0.127
0.52
1.6
0.008
0.005
0.018
2.2
0.15
0.34

1.0


0.0011



0.73


86
EXAMPLE
0.118
0.49
1.8
0.007
0.006
0.024
2.4
0.21
0.30
1.2



0.0012



0.75


87
EXAMPLE
0.136
0.57
1.9
0.007
0.005
0.025
2.6
0.12
0.36

0.8



0.3


0.75


88
EXAMPLE
0.134
0.63
1.6
0.009
0.005
0.015
2.8
0.12
0.37
1.0
0.5



0.4


0.83


89
EXAMPLE
0.136
0.65
1.8
0.008
0.004
0.014
2.5
0.14
0.34
0.8
0.2






0.75


90
EXAMPLE
0.125
0.54
1.5
0.008
0.002
0.012
2.8
0.16
0.39
1.0
0.4






0.78


















TABLE 2-4







WIRE

CHEMICAL COMPOSITION OF WIRE [mass % WITH RESPECT TO TOTAL MASS OF WIRE]


























No.
CATEGORY
C
Si
Mn
P
S
Al
Ni
V
Cu
Cr
Mo
Ti
Nb
B
Mg
Ca
REM
Ceq





























91
EXAMPLE
0.081
0.23
1.0
0.008
0.004
0.012
2.2
0.06

1.0
0.6






0.67


92
EXAMPLE
0.083
0.26
1.2
0.009
0.005
0.012
2.4
0.06
0.108
1.0
0.5
0.015

0.0015



0.68


93
EXAMPLE
0.083
0.25
1.2
0.012
0.005
0.013
2.2
0.07
0.23
1.0
0.6






0.70


94
EXAMPLE
0.093
0.23
1.1
0.009
0.005
0.016
1.8
0.06

0.8
0.6

0.03

0.2


0.65


95
EXAMPLE
0.092
0.24
1.1
0.013
0.004
0.015
1.7
0.07
0.12
0.8
0.6






0.64


96
EXAMPLE
0.098
0.26
1.1
0.013
0.006
0.020
1.8
0.06
0.18
0.7
0.6






0.63


97
EXAMPLE
0.102
0.46
1.2
0.012
0.006
0.023
2.3
0.07

0.8
0.5



0.3

0.0018
0.67


98
EXAMPLE
0.105
0.45
1.1
0.008
0.005
0.021
2.1
0.08
0.11
0.8
0.5
0.012





0.65


99
EXAMPLE
0.106
0.48
1.2
0.008
0.005
0.022
2.3
0.06
0.17
0.7
0.5






0.65


100
EXAMPLE
0.095
0.38
1.0
0.009
0.005
0.018
1.6
0.06

0.3
1.2

0.04


0.2

0.68


101
EXAMPLE
0.086
0.39
1.3
0.009
0.004
0.019
1.5
0.07

0.2
1.3






0.73


102
EXAMPLE
0.089
0.38
1.2
0.015
0.006
0.018
1.8
0.07

0.3
1.2






0.71


103
EXAMPLE
0.093
0.43
1.2
0.016
0.006
0.015
3.2
0.06

1.4
0.3
0.022

0.0016



0.75


104
EXAMPLE
0.082
0.46
2.2
0.015
0.005
0.013
4.8
0.06

0.5







0.69


105
EXAMPLE
0.081
0.45
2.1
0.012
0.004
0.012
4.7
0.06


0.4






0.67


106
EXAMPLE
0.197
0.42
2.1
0.011
0.004
0.013
2.7
0.06









0.64


107
EXAMPLE
0.195
0.40
2.2
0.012
0.004
0.015
2.6
0.28
0.23





0.2


0.66


108
EXAMPLE
0.082
0.40
2.2
0.013
0.004
0.015
3.5
0.27


0.3






0.65


109
COMPARATIVE
0.078
0.32
1.0
0.011
0.004
0.016
2.8
0.06
0.18
0.8
0.6






0.64



EXAMPLE


110
COMPARATIVE
0.075
0.33
1.3
0.012
0.005
0.016
2.7
0.06
0.21
0.8
0.6



0.3


0.69



EXAMPLE


111
COMPARATIVE
0.088
0.38
0.9
0.011
0.005
0.012
2.6
0.06
0.21
0.9
0.8
0.013

0.0020



0.70



EXAMPLE


112
COMPARATIVE
0.082
0.37
0.9
0.012
0.004
0.012
2.4
0.06
0.20
0.9
0.8
0.018





0.69



EXAMPLE


113
COMPARATIVE
0.086
0.42
1.0
0.013
0.004
0.015
2.5
0.04
0.18
1.0
0.4






0.64



EXAMPLE


114
COMPARATIVE
0.094
0.46
1.5
0.013
0.005
0.014
2.6
0.04
0.17
1.0







0.63



EXAMPLE


115
COMPARATIVE
0.064
0.41
2.3
0.012
0.004
0.015
2.8
0.07
0.22

0.3


0.0018



0.61



EXAMPLE


116
COMPARATIVE
0.060
0.45
2.3
0.012
0.005
0.015
2.7
0.07
0.23
0.5


0.02




0.63



EXAMPLE


117
COMPARATIVE
0.086
0.38
2.4
0.011
0.006
0.012
1.8
0.06
0.18
0.5





0.2

0.65



EXAMPLE


118
COMPARATIVE
0.094
0.38
2.6
0.011
0.006
0.013
1.9
0.07


0.3






0.67



EXAMPLE


119
COMPARATIVE
0.088
0.37
2.3
0.013
0.005
0.012
2.5
0.06
0.23

0.3
0.024





0.63



EXAMPLE


120
COMPARATIVE
0.118
0.28
2.3
0.008
0.005
0.011
2.4
0.06
0.23
0.5







0.68



EXAMPLE


121
COMPARATIVE
0.121
0.29
2.3
0.009
0.005
0.012
2.6
0.06
0.18

0.4



0.2


0.69



EXAMPLE


122
COMPARATIVE
0.125
0.28
0.8
0.009
0.004
0.011
2.5
0.06
0.18
0.3
1.0



0.4


0.65



EXAMPLE


123
COMPARATIVE
0.124
0.31
0.8
0.010
0.004
0.011
2.4
0.06
0.15
1.2
0.3


0.0015



0.65



EXAMPLE


124
COMPARATIVE
0.093
0.42
1.1
0.012
0.005
0.018
2.6
0.06

0.8
0.5





0.0024
0.65



EXAMPLE


125
COMPARATIVE
0.106
0.43
1.7
0.012
0.005
0.018
2.4
0.07
0.24

0.6
0.024





0.62



EXAMPLE


126
COMPARATIVE
0.102
0.43
1.8
0.011
0.005
0.017
7.8
0.06
0.26








0.62



EXAMPLE


















TABLE 2-5







WIRE

CHEMICAL COMPOSITION OF WIRE [mass % WITH RESPECT TO TOTAL MASS OF WIRE]


























No.
CATEGORY
C
Si
Mn
P
S
Al
Ni
V
Cu
Cr
Mo
Ti
Nb
B
Mg
Ca
REM
Ceq





























127
COMPARATIVE
0.115
0.42
1.6
0.009
0.004
0.012
2.5
0.12
0.22
1.2

0.022





0.71



EXAMPLE


128
COMPARATIVE
0.118
0.43
1.5
0.010
0.005
0.011
1.5
0.11
0.18
0.8
0.5



0.2


0.72



EXAMPLE


129
COMPARATIVE
0.116
0.46
1.6
0.009
0.008
0.012
2.4
0.11
0.24
0.5
0.5



0.4


0.69



EXAMPLE


130
COMPARATIVE
0.115
0.42
1.8
0.011
0.004
0.008
2.0
0.08
0.15
0.7







0.63



EXAMPLE


131
COMPARATIVE
0.124
0.51
1.8
0.008
0.006
0.012
3.2
0.13
0.18

0.8



0.2


0.73



EXAMPLE


132
COMPARATIVE
0.123
0.48
1.6
0.009
0.006
0.015
3.3
0.12
0.16

1.2
0.015


0.2


0.80



EXAMPLE


133
COMPARATIVE
0.118
0.46
1.5
0.008
0.005
0.016
2.8
0.12
0.22
1.0
0.8

0.02




0.87



EXAMPLE


134
COMPARATIVE
0.119
0.45
1.2
0.011
0.007
0.015
1.2
0.11
0.20
1.2
0.5






0.74



EXAMPLE


135
COMPARATIVE
0.123
0.42
1.5
0.010
0.005
0.015
2.5
0.10
0.18
0.8
0.6



0.4


0.77



EXAMPLE


136
COMPARATIVE
0.078
0.34
1.5
0.008
0.006
0.008
2.9
0.14
0.16
0.5
0.5






0.65



EXAMPLE


137
COMPARATIVE
0.216
0.28
1.8
0.009
0.006
0.012
3.2
0.12
0.36
0.5







0.72



EXAMPLE


138
COMPARATIVE
0.121
0.04
1.4
0.008
0.004
0.011
2.8
0.12
0.38
0.5
0.4
0.025

0.0022


0.0018
0.63



EXAMPLE


139
COMPARATIVE
0.118
1.58
1.4
0.012
0.008
0.008
2.8
0.15
0.34

0.5
0.020

0.0034



0.62



EXAMPLE


140
COMPARATIVE
0.116
0.46
0.8
0.008
0.005
0.005
3.5
0.12
0.26

1.2

0.02

0.2


0.66



EXAMPLE


141
COMPARATIVE
0.112
0.52
2.3
0.008
0.005
0.005
3.5
0.12
0.24





0.4


0.61



EXAMPLE


142
COMPARATIVE
0.126
0.42
1.6
0.025
0.008
0.003
3.4
0.14
0.18
1.0
0.3




0.2

0.78



EXAMPLE


143
COMPARATIVE
0.123
0.40
1.6
0.011
0.024
0.006
3.6
0.13
0.23
1.5





0.2

0.81



EXAMPLE


144
COMPARATIVE
0.117
0.45
1.8
0.008
0.005
0.0008
2.8
0.14
0.27

0.5






0.64



EXAMPLE


145
COMPARATIVE
0.118
0.46
1.6
0.012
0.006
0.422
2.9
0.11
0.32
0.5
0.3






0.66



EXAMPLE


146
COMPARATIVE
0.120
0.46
1.8
0.008
0.005
0.003
0.9
0.13
0.18
0.5
0.2



0.3


0.62



EXAMPLE


147
COMPARATIVE
0.117
0.53
1.9
0.009
0.005
0.004
8.6
0.12
0.43





0.4


0.68



EXAMPLE


148
COMPARATIVE
0.146
0.50
1.5
0.008
0.008
0.003
2.8
0.050
0.18

0.8



0.2


0.69



EXAMPLE


149
COMPARATIVE
0.122
0.54
1.6
0.008
0.004
0.005
3.1
0.31
0.53
1.0




0.3


0.71



EXAMPLE


150
COMPARATIVE
0.118
0.42
1.5
0.011
0.004
0.008
3.3
0.14
0.90

0.6


0.0042



0.63



EXAMPLE


151
COMPARATIVE
0.122
0.38
1.8
0.008
0.005
0.013
2.8
0.13
0.42
2.6

0.022

0.0038



1.04



EXAMPLE


152
COMPARATIVE
0.125
0.36
1.6
0.010
0.004
0.014
2.7
0.14
0.34

2.1
0.024





1.01



EXAMPLE


153
COMPARATIVE
0.123
0.35
1.7
0.008
0.006
0.005
3.0
0.12
0.36
0.3
0.5
0.304





0.69



EXAMPLE


154
COMPARATIVE
0.119
0.38
1.6
0.011
0.005
0.005
3.2
0.13
0.19
0.7


0.06

0.2


0.63



EXAMPLE


155
COMPARATIVE
0.124
0.46
1.5
0.009
0.005
0.008
3.3
0.12
0.26

0.6


0.0115
0.3


0.63



EXAMPLE


156
COMPARATIVE
0.126
0.42
1.5
0.008
0.008
0.013
2.8
0.14
0.27

0.8



0.9


0.67



EXAMPLE


157
COMPARATIVE
0.120
0.52
1.7
0.008
0.004
0.018
2.8
0.12
0.33
0.8





0.6

0.66



EXAMPLE


158
COMPARATIVE
0.117
0.45
1.8
0.009
0.004
0.016
3.4
0.12
0.34

0.5





0.0124
0.65



EXAMPLE


159
COMPARATIVE
0.112
0.52
1.5
0.008
0.004
0.018
1.8
0.12
0.29
0.5
0.2



0.3


0.59



EXAMPLE


160
COMPARATIVE
0.115
0.45
1.8
0.009
0.004
0.016
3.4
0.12
0.18
1.2
1.8



0.2


1.22



EXAMPLE


















TABLE 2-6







WIRE

CHEMICAL COMPOSITION OF WIRE [mass % WITH RESPECT TO TOTAL MASS OF WIRE]


























No.
CATEGORY
C
Si
Mn
P
S
Al
Ni
V
Cu
Cr
Mo
Ti
Nb
B
Mg
Ca
REM
Ceq





























161
EXAMPLE
0.101
0.42
1.6
0.010
0.008
0.008
2.1
0.12
0.21
0.6
0.6


0.0012

0.2

0.72


162
EXAMPLE
0.113
0.53
1.5
0.007
0.005
0.006
2.6
0.08
0.18

1.0
0.018


0.2


0.71


163
EXAMPLE
0.120
0.49
1.8
0.008
0.004
0.014
2.4
0.15

1.2


0.02




0.75


164
EXAMPLE
0.116
0.47
1.8
0.008
0.006
0.018
2.5
0.16
0.22
0.6
0.4





0.0012
0.73


165
EXAMPLE
0.132
0.59
1.7
0.009
0.006
0.009
4.8
0.20
0.22
0.9
0.6
0.023


0.4


0.90


166
EXAMPLE
0.158
0.48
2.0
0.007
0.008
0.026
3.2
0.22









0.61


167
EXAMPLE
0.135
0.68
1.8
0.009
0.006
0.014
2.3
0.18

1.0
0.5



0.2


0.86


168
EXAMPLE
0.123
0.52
1.7
0.010
0.004
0.012
2.5
0.15
0.21

1.2
0.015
0.03




0.80


169
EXAMPLE
0.127
0.56
1.6
0.010
0.005
0.016
2.1
0.16
0.23

0.9


0.0015



0.71


170
EXAMPLE
0.103
0.46
1.9
0.010
0.007
0.011
2.6
0.18
0.20
0.4
0.8






0.80


171
COMPARATIVE
0.115
0.48
1.8
0.013
0.011
0.018
3.1
0.17
0.18
1.0
0.7






0.90



EXAMPLE


172
COMPARATIVE
0.111
0.35
1.8
0.008
0.006
0.012
2.4
0.12
0.21
0.6
1.0
0.013





0.86



EXAMPLE


173
COMPARATIVE
0.109
0.32
1.9
0.007
0.006
0.015
2.6
0.10
0.19
0.9
0.3






0.77



EXAMPLE


174
COMPARATIVE
0.093
0.28
1.8
0.006
0.002
0.016
2.8
0.09
0.32
0.8
0.5






0.77



EXAMPLE


175
EXAMPLE
0.105
0.40
1.7
0.006
0.002
0.010
2.4
0.08
0.22
1.0
0.4






0.77


















TABLE 2-7







WIRE

CHEMICAL COMPOSITION OF WIRE [mass % WITH RESPECT TO TOTAL MASS OF WIRE]


























No.
CATEGORY
C
Si
Mn
P
S
Al
Ni
V
Cu
Cr
Mo
Ti
Nb
B
Mg
Ca
REM
Ceq





 5-2
EXAMPLE
0.102
0.46
1.8
0.008
0.003
0.005
2.4
0.08
0.23
0.8
0.8






0.85


 6-2
EXAMPLE
0.103
0.38
1.2
0.009
0.005
0.002
2.6
0.09
0.18
1.2
0.6
0.017

0.0042


0.0012
0.78


30-2
EXAMPLE
0.126
0.33
1.5
0.010
0.005
0.047
2.9
0.18
0.28
2.5







0.98


61-2
EXAMPLE
0.111
0.80
1.4
0.010
0.008
0.003
3.5
0.16
0.25
0.8
0.5



0.4


0.76


62-2
EXAMPLE
0.139
0.45
1.8
0.008
0.007
0.025
5.6
0.23
0.90








0.61


90-2
EXAMPLE
0.125
0.54
1.5
0.008
0.002
0.012
2.8
0.16
0.39
1.0
0.4






0.78


















TABLE 3-1









WELDING CONDITIONS




















WELDING
HEAT
PREHEATING
INTERPASS

FLOW RATE


WIRE

CURRENT
VOLTAGE
SPEED
INPUT
TEMPERATURE
TEMPERATURE

OF GAS


No.
CATEGORY
[A]
[V]
[cm/min]
[kJ/cm]
[° C.]
[° C.]
SHIELD GAS
[L/min]



















1
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


2
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


3
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


4
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


5
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


6
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


7
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


8
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


9
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


10
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


11
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


12
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


13
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


14
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


15
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


16
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


17
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


18
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


19
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


20
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


21
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


22
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


23
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


24
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


25
EXAMPLE
280
30
30
16.8
50
150 OR LESS
100%CO2
25


26
EXAMPLE
280
30
30
16.8
50
150 OR LESS
100%CO2
25


27
EXAMPLE
280
30
30
16.8
50
150 OR LESS
100%CO2
25


28
EXAMPLE
280
30
30
16.8
50
150 OR LESS
100%CO2
25


29
EXAMPLE
280
30
30
16.8
50
150 OR LESS
100%CO2
25


30
EXAMPLE
280
30
30
16.8
50
150 OR LESS
100%CO2
25


















TABLE 3-2









WELDING CONDITIONS



















VOLT-
WELDING
HEAT
PREHEATING
INTERPASS

FLOW RATE


WIRE

CURRENT
AGE
SPEED
INPUT
TEMPERATURE
TEMPERATURE

OF GAS


No.
CATEGORY
[A]
[V]
[cm/min]
[kJ/cm]
[° C.]
[° C.]
SHIELD GAS
[L/min]





31
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


32
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


33
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


34
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


35
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


36
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


37
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


38
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


39
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


40
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


41
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


42
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


43
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


44
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


45
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


46
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


47
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


48
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


49
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


50
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


51
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


52
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


53
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


54
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


55
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


56
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


57
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


58
EXAMPLE
280
30
30
16.8
50
150 OR LESS
100%CO2
25


59
EXAMPLE
280
30
30
16.8
50
150 OR LESS
100%CO2
25


60
EXAMPLE
280
30
30
16.8
50
150 OR LESS
100%CO2
25


















TABLE 3-3









WELDING CONDITIONS



















VOLT-
WELDING
HEAT
PREHEATING
INTERPASS

FLOW RATE


WIRE

CURRENT
AGE
SPEED
INPUT
TEMPERATURE
TEMPERATURE

OF GAS


No.
CATEGORY
[A]
[V]
[cm/min]
[kJ/cm]
[° C.]
[° C.]
SHIELD GAS
[L/min]





61
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


62
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


63
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


64
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


65
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


66
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


67
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


68
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


69
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


70
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


71
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


72
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


73
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


74
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


75
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


76
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


77
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


78
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


79
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


80
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


81
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


82
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


83
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


84
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


85
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


86
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


87
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


88
EXAMPLE
280
30
30
16.8
50
150 OR LESS
100%CO2
25


89
EXAMPLE
280
30
30
16.8
50
150 OR LESS
100%CO2
25


90
EXAMPLE
280
30
30
16.8
50
150 OR LESS
100%CO2
25


















TABLE 3-4









WELDING CONDITIONS



















VOLT-
WELDING
HEAT
PREHEATING
INTERPASS

FLOW RATE


WIRE

CURRENT
AGE
SPEED
INPUT
TEMPERATURE
TEMPERATURE

OF GAS


No.
CATEGORY
[A]
[V]
[cm/min]
[kJ/cm]
[° C.]
[° C.]
SHIELD GAS
[L/min]



















91
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


92
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


93
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


94
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


95
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


96
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


97
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


98
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


99
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


100
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


101
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


102
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


103
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


104
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


105
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


106
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


107
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


108
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


109
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


110
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


111
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


112
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


113
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


114
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


115
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


116
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


117
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


118
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


119
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


120
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


121
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


122
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


123
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


124
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


125
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


126
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


















TABLE 3-5









WELDING CONDITIONS



















VOLT-
WELDING
HEAT
PREHEATING
INTERPASS

FLOW RATE


WIRE

CURRENT
AGE
SPEED
INPUT
TEMPERATURE
TEMPERATURE

OF GAS


No.
CATEGORY
[A]
[V]
[cm/min]
[kJ/cm]
[° C.]
[° C.]
SHIELD GAS
[L/min]





127
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


128
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


129
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


130
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


131
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


132
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


133
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


134
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


135
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


136
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


137
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


138
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


139
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


140
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


141
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


142
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


143
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


144
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


145
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


146
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


147
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


148
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


149
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


150
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


151
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


152
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


153
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


154
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


155
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


156
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


157
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


158
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


159
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


160
COMPARATIVE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


















TABLE 3-6









WELDING CONDITIONS



















VOLT-
WELDING
HEAT
PREHEATING
INTERPASS

FLOW RATE


WIRE

CURRENT
AGE
SPEED
INPUT
TEMPERATURE
TEMPERATURE

OF GAS


No.
CATEGORY
[A]
[V]
[cm/min]
[kJ/cm]
[° C.]
[° C.]
SHIELD GAS
[L/min]





161
EXAMPLE
280
30
30
16.8
NO PREHEATING
150 OR LESS
Ar—20%CO2
25


162
EXAMPLE
280
30
30
16.8
NO PREHEATING
150 OR LESS
Ar—20%CO2
25


163
EXAMPLE
280
30
30
16.8
NO PREHEATING
150 OR LESS
Ar—20%CO2
25


164
EXAMPLE
280
30
30
16.8
NO PREHEATING
150 OR LESS
100%CO2
25


165
EXAMPLE
280
30
30
16.8
 50
150 OR LESS
Ar—20%CO2
25


166
EXAMPLE
280
30
30
16.8
NO PREHEATING
150 OR LESS
Ar—20%CO2
25


167
EXAMPLE
280
30
30
16.8
 50
150 OR LESS
100%CO2
25


168
EXAMPLE
280
30
30
16.8
 50
150 OR LESS
Ar—20%CO2
25


169
EXAMPLE
280
30
30
16.8
NO PREHEATING
150 OR LESS
100%CO2
25


170
EXAMPLE
280
30
30
16.8
 50
150 OR LESS
100%CO2
25


171
COMPARATIVE
280
30
30
16.8
 50
150 OR LESS
Ar—20%CO2
25



EXAMPLE


172
COMPARATIVE
280
30
30
16.8
150
150 OR LESS
Ar—20%CO2
25



EXAMPLE


173
COMPARATIVE
280
30
30
16.8
150
150 OR LESS
Ar—20%CO2
25



EXAMPLE


174
COMPARATIVE
280
30
30
16.8
150
150 OR LESS
Ar—20%CO2
25



EXAMPLE


175
EXAMPLE
280
30
30
16.8
100
150 OR LESS
Ar—20%CO2
25


















TABLE 3-7









WELDING CONDITIONS



















VOLT-
WELDING
HEAT
PREHEATING
INTERPASS

FLOW RATE


WIRE

CURRENT
AGE
SPEED
INPUT
TEMPERATURE
TEMPERATURE

OF GAS


NO.
CATEGORY
[A]
[V]
[cm/min]
[kJ/cm]
[° C.]
[° C.]
SHIELD GAS
[L/min]





 5-2
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


 6-2
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


30-2
EXAMPLE
280
30
30
16.8
50
150 OR LESS
100%CO2
25


61-2
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


62-2
EXAMPLE
280
30
30
16.8
50
150 OR LESS
Ar—20%CO2
25


90-2
EXAMPLE
280
30
30
16.8
50
150 OR LESS
100%CO2
25


























TABLE 4-1










CHARPY




OVER-






FRACTURE
ABSORBED




ALL




YIELD
TENSILE
ELON-
ENERGY
DIFFUSIBLE

ELON-

DETER-


WIRE

STRENGTH
STRENGTH
GATION
AT −40° C.
HYDROGEN

GA-
TOUGH-
MINA-


NO.
CATEGORY
[MPa]
[MPa]
[%]
[J]
[ml/100 g]
STRENGTH
TION
NESS
TION

























1
EXAMPLE
896
962
15.2
62
0.8
PASS
PASS
PASS
PASS


2
EXAMPLE
997
1084
18.6
59
0.9
PASS
PASS
PASS
PASS


3
EXAMPLE
904
978
16.8
60
0.7
PASS
PASS
PASS
PASS


4
EXAMPLE
1036
1141
17.6
51
0.9
PASS
PASS
PASS
PASS


5
EXAMPLE
1084
1226
19.4
38
0.8
PASS
PASS
PASS
PASS


6
EXAMPLE
1046
1197
18.2
41
0.7
PASS
PASS
PASS
PASS


7
EXAMPLE
1033
1131
17.2
46
0.6
PASS
PASS
PASS
PASS


8
EXAMPLE
1048
1184
16.1
45
0.7
PASS
PASS
PASS
PASS


9
EXAMPLE
1106
1264
15.4
36
0.6
PASS
PASS
PASS
PASS


10
EXAMPLE
925
1013
18.5
53
0.7
PASS
PASS
PASS
PASS


11
EXAMPLE
910
997
19.6
59
0.9
PASS
PASS
PASS
PASS


12
EXAMPLE
921
979
18.2
57
0.8
PASS
PASS
PASS
PASS


13
EXAMPLE
1094
1275
15.3
36
0.8
PASS
PASS
PASS
PASS


14
EXAMPLE
914
1004
19.1
49
0.7
PASS
PASS
PASS
PASS


15
EXAMPLE
980
1067
17.9
47
0.5
PASS
PASS
PASS
PASS


16
EXAMPLE
1078
1216
16.8
40
0.9
PASS
PASS
PASS
PASS


17
EXAMPLE
1094
1203
16.5
37
0.7
PASS
PASS
PASS
PASS


18
EXAMPLE
1116
1297
14.6
34
0.9
PASS
PASS
PASS
PASS


19
EXAMPLE
946
1062
18.5
49
0.9
PASS
PASS
PASS
PASS


20
EXAMPLE
953
1049
17.9
52
0.9
PASS
PASS
PASS
PASS


21
EXAMPLE
1081
1226
15.7
39
0.7
PASS
PASS
PASS
PASS


22
EXAMPLE
1073
1216
15.4
40
0.8
PASS
PASS
PASS
PASS


23
EXAMPLE
892
973
18.9
56
0.8
PASS
PASS
PASS
PASS


24
EXAMPLE
1110
1254
17.0
37
0.9
PASS
PASS
PASS
PASS


25
EXAMPLE
1134
1315
15.2
33
1.0
PASS
PASS
PASS
PASS


26
EXAMPLE
1097
1234
17.3
38
0.6
PASS
PASS
PASS
PASS


27
EXAMPLE
1112
1273
16.9
36
0.7
PASS
PASS
PASS
PASS


28
EXAMPLE
1071
1208
17.8
39
0.6
PASS
PASS
PASS
PASS


29
EXAMPLE
902
989
19.5
58
0.7
PASS
PASS
PASS
PASS


30
EXAMPLE
1125
1301
15.8
35
0.7
PASS
PASS
PASS
PASS


























TABLE 4-2










CHARPY




OVER-






FRACTURE
ABSORBED




ALL




YIELD
TENSILE
ELON-
ENERGY
DIFFUSIBLE

ELON-

DETER-


WIRE

STRENGTH
STRENGTH
GATION
AT −40° C.
HYDROGEN

GA-
TOUGH-
MINA-


NO.
CATEGORY
[MPa]
[MPa]
[%]
[J]
[ml/100 g]
STRENGTH
TION
NESS
TION

























31
EXAMPLE
999
1079
13.6
49
0.7
PASS
PASS
PASS
PASS


32
EXAMPLE
871
957
14.0
56
0.8
PASS
PASS
PASS
PASS


33
EXAMPLE
925
1056
17.6
48
0.9
PASS
PASS
PASS
PASS


34
EXAMPLE
930
1043
17.0
49
0.9
PASS
PASS
PASS
PASS


35
EXAMPLE
922
1069
17.6
46
0.8
PASS
PASS
PASS
PASS


36
EXAMPLE
1038
1227
16.8
39
0.9
PASS
PASS
PASS
PASS


37
EXAMPLE
1067
1211
16.2
37
0.9
PASS
PASS
PASS
PASS


38
EXAMPLE
1055
1219
16.6
39
0.8
PASS
PASS
PASS
PASS


39
EXAMPLE
1107
1289
15.9
35
0.5
PASS
PASS
PASS
PASS


40
EXAMPLE
1169
1435
13.0
27
0.7
PASS
PASS
PASS
PASS


41
EXAMPLE
1157
1384
15.4
30
0.9
PASS
PASS
PASS
PASS


42
EXAMPLE
1160
1341
15.9
32
0.9
PASS
PASS
PASS
PASS


43
EXAMPLE
1142
1330
16.2
33
0.7
PASS
PASS
PASS
PASS


44
EXAMPLE
1106
1287
17.6
34
0.7
PASS
PASS
PASS
PASS


45
EXAMPLE
1118
1280
17.1
36
0.9
PASS
PASS
PASS
PASS


46
EXAMPLE
1093
1297
17.5
35
0.8
PASS
PASS
PASS
PASS


47
EXAMPLE
1080
1246
18.0
39
0.9
PASS
PASS
PASS
PASS


48
EXAMPLE
1082
1221
17.5
40
0.9
PASS
PASS
PASS
PASS


49
EXAMPLE
1089
1249
17.2
37
0.7
PASS
PASS
PASS
PASS


50
EXAMPLE
1134
1254
16.1
39
0.7
PASS
PASS
PASS
PASS


51
EXAMPLE
1117
1265
17.8
38
0.6
PASS
PASS
PASS
PASS


52
EXAMPLE
1122
1275
17.6
37
0.8
PASS
PASS
PASS
PASS


53
EXAMPLE
1146
1308
16.1
33
0.8
PASS
PASS
PASS
PASS


54
EXAMPLE
1137
1379
15.2
29
0.7
PASS
PASS
PASS
PASS


55
EXAMPLE
1129
1288
15.7
32
0.9
PASS
PASS
PASS
PASS


56
EXAMPLE
1116
1276
15.3
34
0.8
PASS
PASS
PASS
PASS


57
EXAMPLE
1191
1429
12.2
28
0.9
PASS
PASS
PASS
PASS


58
EXAMPLE
1154
1307
14.5
36
1.0
PASS
PASS
PASS
PASS


59
EXAMPLE
1209
1400
12.1
30
0.8
PASS
PASS
PASS
PASS


60
EXAMPLE
1184
1384
12.6
29
0.7
PASS
PASS
PASS
PASS


























TABLE 4-3










CHARPY




OVER-






FRACTURE
ABSORBED




ALL




YIELD
TENSILE
ELON-
ENERGY
DIFFUSIBLE

ELON-

DETER-


WIRE

STRENGTH
STRENGTH
GATION
AT −40° C.
HYDROGEN

GA-
TOUGH-
MINA-


NO.
CATEGORY
[MPa]
[MPa]
[%]
[J]
[ml/100 g]
STRENGTH
TION
NESS
TION







61
EXAMPLE
1113
1268
16.4
36
0.7
PASS
PASS
PASS
PASS


62
EXAMPLE
1026
1120
18.6
44
0.9
PASS
PASS
PASS
PASS


63
EXAMPLE
1072
1236
16.2
39
0.8
PASS
PASS
PASS
PASS


64
EXAMPLE
1108
1289
15.5
34
0.7
PASS
PASS
PASS
PASS


65
EXAMPLE
1120
1278
16.3
35
0.6
PASS
PASS
PASS
PASS


66
EXAMPLE
1125
1294
15.9
35
0.5
PASS
PASS
PASS
PASS


67
EXAMPLE
1064
1205
18.2
43
0.6
PASS
PASS
PASS
PASS


68
EXAMPLE
1055
1216
18.1
42
0.9
PASS
PASS
PASS
PASS


69
EXAMPLE
1029
1164
19.3
46
0.7
PASS
PASS
PASS
PASS


70
EXAMPLE
1118
1263
17.8
39
0.9
PASS
PASS
PASS
PASS


71
EXAMPLE
1076
1217
16.5
41
0.8
PASS
PASS
PASS
PASS


72
EXAMPLE
1146
1327
13.8
32
0.9
PASS
PASS
PASS
PASS


73
EXAMPLE
1052
1201
17.6
45
0.7
PASS
PASS
PASS
PASS


74
EXAMPLE
1127
1293
15.4
37
0.7
PASS
PASS
PASS
PASS


75
EXAMPLE
1115
1280
15.7
35
0.7
PASS
PASS
PASS
PASS


76
EXAMPLE
1101
1261
16.3
36
0.7
PASS
PASS
PASS
PASS


77
EXAMPLE
1129
1288
16.1
34
0.9
PASS
PASS
PASS
PASS


78
EXAMPLE
1108
1243
16.4
36
0.8
PASS
PASS
PASS
PASS


79
EXAMPLE
1124
1275
15.8
36
0.7
PASS
PASS
PASS
PASS


80
EXAMPLE
1118
1279
15.0
33
0.8
PASS
PASS
PASS
PASS


81
EXAMPLE
1079
1202
19.2
42
0.8
PASS
PASS
PASS
PASS


82
EXAMPLE
1087
1230
18.8
38
0.8
PASS
PASS
PASS
PASS


83
EXAMPLE
1066
1214
18.0
38
0.7
PASS
PASS
PASS
PASS


84
EXAMPLE
1105
1238
17.4
36
0.9
PASS
PASS
PASS
PASS


85
EXAMPLE
1099
1232
17.5
37
0.7
PASS
PASS
PASS
PASS


86
EXAMPLE
1125
1245
18.2
37
0.8
PASS
PASS
PASS
PASS


87
EXAMPLE
1120
1290
15.2
34
0.9
PASS
PASS
PASS
PASS


88
EXAMPLE
1131
1315
14.0
29
0.9
PASS
PASS
PASS
PASS


89
EXAMPLE
1174
1301
13.3
30
0.7
PASS
PASS
PASS
PASS


90
EXAMPLE
1155
1333
12.4
28
0.6
PASS
PASS
PASS
PASS


























TABLE 4-4










CHARPY




OVER-






FRACTURE
ABSORBED




ALL




YIELD
TENSILE
ELON-
ENERGY
DIFFUSIBLE

ELON-

DETER-


WIRE

STRENGTH
STRENGTH
GATION
AT −40° C.
HYDROGEN

GA-
TOUGH-
MINA-


NO.
CATEGORY
[MPa]
[MPa]
[%]
[J]
[ml/100 g]
STRENGTH
TION
NESS
TION

























91
EXAMPLE
903
989
13.8
59
0.7
PASS
PASS
PASS
PASS


92
EXAMPLE
884
975
15.3
55
0.9
PASS
PASS
PASS
PASS


93
EXAMPLE
913
984
15.5
56
0.5
PASS
PASS
PASS
PASS


94
EXAMPLE
897
968
14.3
53
0.7
PASS
PASS
PASS
PASS


95
EXAMPLE
901
976
15.2
58
0.9
PASS
PASS
PASS
PASS


96
EXAMPLE
908
987
18.9
60
0.8
PASS
PASS
PASS
PASS


97
EXAMPLE
943
1067
15.0
51
0.9
PASS
PASS
PASS
PASS


98
EXAMPLE
987
1097
16.4
50
0.9
PASS
PASS
PASS
PASS


99
EXAMPLE
975
1082
17.7
53
0.9
PASS
PASS
PASS
PASS


100
EXAMPLE
912
994
14.7
55
0.9
PASS
PASS
PASS
PASS


101
EXAMPLE
918
1005
14.9
52
0.8
PASS
PASS
PASS
PASS


102
EXAMPLE
904
987
15.9
57
0.9
PASS
PASS
PASS
PASS


103
EXAMPLE
926
1021
14.5
49
0.7
PASS
PASS
PASS
PASS


104
EXAMPLE
905
1013
13.0
52
0.7
PASS
PASS
PASS
PASS


105
EXAMPLE
915
1035
13.5
50
0.7
PASS
PASS
PASS
PASS


106
EXAMPLE
1134
1342
12.1
28
0.9
PASS
PASS
PASS
PASS


107
EXAMPLE
1152
1371
12.2
27
0.8
PASS
PASS
PASS
PASS


108
EXAMPLE
910
990
13.8
54
0.7
PASS
PASS
PASS
PASS


109
COMPARATIVE
856
946
14.5
61
0.9
FAIL
PASS
PASS
FAIL



EXAMPLE


110
COMPARATIVE
843
935
15.2
59
0.7
FAIL
PASS
PASS
FAIL



EXAMPLE


111
COMPARATIVE
897
994
10.6
57
0.9
PASS
FAIL
PASS
FAIL



EXAMPLE


112
COMPARATIVE
934
1014
9.9
53
0.9
PASS
FAIL
PASS
FAIL



EXAMPLE


113
COMPARATIVE
901
987
5.4
51
0.8
PASS
FAIL
PASS
FAIL



EXAMPLE


114
COMPARATIVE
936
1022
4.9
54
0.7
PASS
FAIL
PASS
FAIL



EXAMPLE


115
COMPARATIVE
732
824
18.9
69
0.7
FAIL
PASS
PASS
FAIL



EXAMPLE


116
COMPARATIVE
729
836
19.0
64
0.6
FAIL
PASS
PASS
FAIL



EXAMPLE


117
COMPARATIVE
902
987
16.6
25
0.8
PASS
PASS
FAIL
FAIL



EXAMPLE


118
COMPARATIVE
892
965
16.0
26
0.7
PASS
PASS
FAIL
FAIL



EXAMPLE


119
COMPARATIVE
899
996
16.1
24
0.7
PASS
PASS
FAIL
FAIL



EXAMPLE


120
COMPARATIVE
1121
1240
14.2
19
0.7
PASS
PASS
FAIL
FAIL



EXAMPLE


121
COMPARATIVE
1130
1255
13.5
17
0.9
PASS
PASS
FAIL
FAIL



EXAMPLE


122
COMPARATIVE
1104
1231
9.0
35
0.7
PASS
FAIL
PASS
FAIL



EXAMPLE


123
COMPARATIVE
1087
1209
9.3
32
0.8
PASS
FAIL
PASS
FAIL



EXAMPLE


124
COMPARATIVE
963
1036
3.5
45
0.8
PASS
FAIL
PASS
FAIL



EXAMPLE


125
COMPARATIVE
955
1058
4.1
42
0.6
PASS
FAIL
PASS
FAIL



EXAMPLE


126
COMPARATIVE
974
1063
3.6
42
0.9
PASS
FAIL
PASS
FAIL



EXAMPLE


























TABLE 4-5










CHARPY




OVER-






FRACTURE
ABSORBED




ALL




YIELD
TENSILE
ELON-
ENERGY
DIFFUSIBLE

ELON-

DETER-


WIRE

STRENGTH
STRENGTH
GATION
AT −40° C.
HYDROGEN

GA-
TOUGH-
MINA-


NO.
CATEGORY
[MPa]
[MPa]
[%]
[J]
[ml/100 g]
STRENGTH
TION
NESS
TION

























127
COMPARATIVE
1082
1224
10.8
23
0.7
PASS
FAIL
FAIL
FAIL



EXAMPLE













128
COMPARATIVE
NOT EVALUATED DUE TO INFERIOR WELDING WORKABILITY
—
—
—
FAIL



EXAMPLE

















129
COMPARATIVE
1067
1215
11.0
24
0.8
PASS
FAIL
FAIL
FAIL



EXAMPLE













130
COMPARATIVE
NOT EVALUATED DUE TO INFERIOR WELDING WORKABILITY
—
—
—
FAIL



EXAMPLE

















131
COMPARATIVE
1008
1123
4.6
31
0.6
PASS
FAIL
PASS
FAIL



EXAMPLE


132
COMPARATIVE
1072
1236
3.1
29
0.7
PASS
FAIL
PASS
FAIL



EXAMPLE


133
COMPARATIVE
1106
1274
14.2
20
0.9
PASS
PASS
FAIL
FAIL



EXAMPLE


134
COMPARATIVE
1061
1219
17.6
18
0.7
PASS
PASS
FAIL
FAIL



EXAMPLE













135
COMPARATIVE
NOT EVALUATED DUE TO INFERIOR WELDING WORKABILITY
—
—
—
FAIL



EXAMPLE

















136
COMPARATIVE
843
941
18.5
62
0.7
FAIL
PASS
PASS
FAIL



EXAMPLE


137
COMPARATIVE
1142
1362
12.0
23
0.8
PASS
PASS
FAIL
FAIL



EXAMPLE


138
COMPARATIVE
981
1097
17.2
25
0.8
PASS
PASS
FAIL
FAIL



EXAMPLE


139
COMPARATIVE
1005
1120
17.0
23
0.8
PASS
PASS
FAIL
FAIL



EXAMPLE


140
COMPARATIVE
1094
1223
10.8
34
0.9
PASS
FAIL
PASS
FAIL



EXAMPLE


141
COMPARATIVE
1132
1245
16.9
23
0.9
PASS
PASS
FAIL
FAIL



EXAMPLE


142
COMPARATIVE
1111
1285
6.8
13
0.7
PASS
FAIL
FAIL
FAIL



EXAMPLE


143
COMPARATIVE
1129
1273
3.4
17
0.7
PASS
FAIL
FAIL
FAIL



EXAMPLE


144
COMPARATIVE
997
1102
16.3
15
0.8
PASS
PASS
FAIL
FAIL



EXAMPLE


145
COMPARATIVE
994
1085
15.9
18
0.6
PASS
PASS
FAIL
FAIL



EXAMPLE


146
COMPARATIVE
986
1068
17.6
24
0.6
PASS
PASS
FAIL
FAIL



EXAMPLE













147
COMPARATIVE
NOT EVALUATED DUE TO INFERIOR WELDING WORKABILITY
—
—
—
FAIL



EXAMPLE

















148
COMPARATIVE
1124
1320
3.6
40
0.8
PASS
FAIL
PASS
FAIL



EXAMPLE


149
COMPARATIVE
1104
1259
17.5
22
0.9
PASS
PASS
FAIL
FAIL



EXAMPLE


150
COMPARATIVE
975
1076
18.4
19
0.7
PASS
PASS
FAIL
FAIL



EXAMPLE


151
COMPARATIVE
1167
1327
15.1
16
0.8
PASS
PASS
FAIL
FAIL



EXAMPLE


152
COMPARATIVE
1125
1299
14.6
13
0.7
PASS
PASS
FAIL
FAIL



EXAMPLE


153
COMPARATIVE
1062
1172
13.8
14
0.8
PASS
PASS
FAIL
FAIL



EXAMPLE


154
COMPARATIVE
972
1083
18.9
20
0.7
PASS
PASS
FAIL
FAIL



EXAMPLE


155
COMPARATIVE
969
1058
18.6
18
0.7
PASS
PASS
FAIL
FAIL



EXAMPLE


156
COMPARATIVE
1046
1175
16.9
22
0.8
PASS
PASS
FAIL
FAIL



EXAMPLE


157
COMPARATIVE
1080
1201
12.6
24
0.9
PASS
PASS
FAIL
FAIL



EXAMPLE


158
COMPARATIVE
1033
1122
13.0
21
0.9
PASS
PASS
FAIL
FAIL



EXAMPLE


159
COMPARATIVE
873
947
18.2
58
0.7
FAIL
PASS
PASS
FAIL



EXAMPLE


160
COMPARATIVE
1123
1297
14.2
23
0.8
PASS
PASS
FAIL
FAIL



EXAMPLE


























TABLE 4-6










CHARPY




OVER-






FRACTURE
ABSORBED




ALL




YIELD
TENSILE
ELON-
ENERGY
DIFFUSIBLE

ELON-

DETER-


WIRE

STRENGTH
STRENGTH
GATION
AT −40° C.
HYDROGEN

GA-
TOUGH-
MINA-


NO.
CATEGORY
[MPa]
[MPa]
[%]
[J]
[ml/100 g]
STRENGTH
TION
NESS
TION

























161
EXAMPLE
1022
1185
17.5
42
0.8
PASS
PASS
PASS
PASS


162
EXAMPLE
1054
1209
18.3
37
0.6
PASS
PASS
PASS
PASS


163
EXAMPLE
1042
1236
18.0
35
0.9
PASS
PASS
PASS
PASS


164
EXAMPLE
1033
1140
17.8
41
0.7
PASS
PASS
PASS
PASS


165
EXAMPLE
1115
1327
14.2
29
0.9
PASS
PASS
PASS
PASS


166
EXAMPLE
962
1075
16.9
45
0.7
PASS
PASS
PASS
PASS


167
EXAMPLE
1120
1302
14.7
31
0.8
PASS
PASS
PASS
PASS


168
EXAMPLE
1062
1204
17.6
36
0.9
PASS
PASS
PASS
PASS


169
EXAMPLE
1041
1182
16.7
37
0.6
PASS
PASS
PASS
PASS


170
EXAMPLE
1013
1154
17.0
37
1.0
PASS
PASS
PASS
PASS













171
COMPARA-
NOT EVALUATED DUE TO INFERIOR WELDING BEAD
—
—
—
FAIL



TIVE
APPEARANCE



EXAMPLE

















172
COMPARA-
1016
1242
2.8
22
4.8
PASS
FAIL
FAIL
FAIL



TIVE



EXAMPLE


173
COMPARA-
1008
1218
2.2
23
4.5
PASS
FAIL
FAIL
FAIL



TIVE



EXAMPLE


174
COMPARA-
994
1107
8.9
43
2.6
PASS
FAIL
PASS
FAIL



TIVE



EXAMPLE


175
EXAMPLE
1082
1267
15.5
32
1.6
PASS
PASS
PASS
PASS


























TABLE 4-7










CHARPY




OVER-






FRACTURE
ABSORBED




ALL




YIELD
TENSILE
ELON-
ENERGY
DIFFUSIBLE

ELON-

DETER-


WIRE

STRENGTH
STRENGTH
GATION
AT −40° C.
HYDROGEN

GA-
TOUGH-
MINA-


NO.
CATEGORY
[MPa]
[MPa]
[%]
[J]
[ml/100 g]
STRENGTH
TION
NESS
TION







 5-2
EXAMPLE
1062
1212
19.6
39
0.8
PASS
PASS
PASS
PASS


 6-2
EXAMPLE
1049
1204
18.0
39
0.7
PASS
PASS
PASS
PASS


30-2
EXAMPLE
1112
1285
16.3
37
0.7
PASS
PASS
PASS
PASS


61-2
EXAMPLE
1120
1265
16.3
35
0.7
PASS
PASS
PASS
PASS


62-2
EXAMPLE
1041
1127
18.4
42
0.9
PASS
PASS
PASS
PASS


90-2
EXAMPLE
1141
1319
12.2
28
0.6
PASS
PASS
PASS
PASS























TABLE 5












CHARPY









ABSORBED




YIELD
TENSILE
FRACTURE
ENERGY
DIFFUSIBLE
CRACK ARREST


WIRE

STRENGTH
STRENGTH
ELONGATION
AT −40° C.
HYDROGEN
TEMPERATURE


NO.
CATEGORY
[MPa]
[MPa]
[%]
[J]
[ml/100 g]
[° C.]





161
EXAMPLE
1022
1185
17.5
42
0.8
20


162
EXAMPLE
1054
1209
18.3
37
0.6
20


163
EXAMPLE
1042
1236
18.0
35
0.9
20


168
EXAMPLE
1062
1204
17.6
36
0.9
20


170
EXAMPLE
1013
1154
17.0
37
1.0
50


172
COMPARATIVE
1016
1242
2.8
22
4.8
150



EXAMPLE


173
COMPARATIVE
1008
1218
2.2
23
4.5
150



EXAMPLE


174
COMPARATIVE
994
1107
8.9
43
2.6
100



EXAMPLE


175
EXAMPLE
1082
1267
15.5
32
1.6
100





















CRITICAL




WIRE



PREHEATING
OVERALL



NO.
STRENGTH
ELONGATION
TOUGHNESS
TEMPERATURE
DETERMINATION







161
PASS
PASS
PASS
PASS
PASS



162
PASS
PASS
PASS
PASS
PASS



163
PASS
PASS
PASS
PASS
PASS



168
PASS
PASS
PASS
PASS
PASS



170
PASS
PASS
PASS
PASS
PASS



172
PASS
FAIL
FAIL
FAIL
FAIL



173
PASS
FAIL
FAIL
FAIL
FAIL



174
PASS
FAIL
PASS
FAIL
FAIL



175
PASS
PASS
PASS
FAIL
FAIL



















TABLE 6









MECHANICAL CHARACTERISTICS







































CHARPY


















ABSORBED


STEEL
PLATE












YIELD
TENSILE
ENERGY












PLATE
THICK-
CHEMICAL COMPOSITION OF STEEL PLATE [MASS %]
STRENGTH
STRENGTH
AT −40° C.























NO.
NESS
C
Si
Mn
P
S
Al
Ni
Mo
Ti
N
0
Ceq
[MPa]
[MPa]
[J]





PL12
25
0.168
0.28
1.4
0.010
0.002
0.035
0.2
0.5
0.015
0.0040
0.0017
0.54
1105
1191
48

## Claims

1. A flux-cored wire for welding an ultrahigh tensile strength steel, which is a flux-cored wire for gas-shielded arc welding, the flux-cored wire comprising:
an outer steel sheath; and
a flux filled into the outer steel sheath,

wherein the flux comprises:
CaF2, alone or in combination with one or more selected from the group consisting of BaF2, SrF2, and MgF2, wherein a total amount thereof is defined as α, and α is more than 2.0% and equal to or less than 8.0% in terms of mass % with respect to a total mass of the wire,
one or more selected from the group consisting of Ti oxide, Si oxide, Mg oxide, and Al oxide, wherein a total amount thereof is defined as β, and β is 0.01% to 1.20% in terms of mass % with respect to the total mass of the wire,
one or more selected from the group consisting of CaCO3, BaCO3, SrCO3, and MgCO3, wherein a total amount thereof is 0% or more and less than 0.60% in terms of mass % with respect to the total mass of the wire, and
iron powder in an amount of 0% or more and less than 5.0% in terms of mass % with respect to the total mass of the wire,
wherein a ratio of an amount of the CaF2 with respect to the α is 0.50 or more,
wherein a ratio of the α with respect to the β is 2.0 to 800.0,
wherein the flux-cored wire comprises C, Si, Mn, Al, Ni, V, P, S, Cu, Cr, Mo, Ti, Nb, B, Mg, Ca, REM, and a remainder iron and impurities, and wherein a total amount of each of these components in an outer skin and the flux, in terms of mass % with respect to the total mass of the wire, is:
C: more than 0.080% and equal to or less than 0.200%,
Si: 0.05% to 1.50%,
Mn: 1.0% to 2.2%,
Al: 0.001% to 0.400%,
Ni: 1.0% to 9.0%,
V: more than 0.050% and equal to or less than 0.300%,
P: 0.020% or less,
S: 0.020% or less,
Cu: 0% to 0.800%,
Cr: 0% to 2.5%,
Mo: 0% to 2.0%,
Ti: 0% to 0.300%,
Nb: 0% to 0.05%,
B: 0% to 0.0100%,
Mg: 0% to 0.8%,
Ca: 0% to 0.5%, and
REM: 0% to 0.0100%, and
Ceq defined in following Expression (a) is 0.60% to 1.20%,


Ceq=[C]+[Si]/24+[Mn]/6+[Ni]/40+[Cr]/5+[Mo]/4+[V]/14  (a)


in which elements noted in brackets represent amounts of the respective elements in terms of mass %.

2. The flux-cored wire for welding the ultrahigh tensile strength steel according to claim 1,
wherein an amount of CaO in the wire is less than 0.15% in terms of mass % with respect to the total mass of the wire.

3. The flux-cored wire for welding the ultrahigh tensile strength steel according to claim 1 or 2,
wherein the ratio of the amount of CaF2 with respect to the α is 0.90 or more.

4. The flux-cored wire for welding the ultrahigh tensile strength steel according to claim 1,
wherein in a tensile test of a deposited metal which is defined in Japanese Industrial Standards JIS Z 3111-2005 with respect to gas-shielded arc welding using the wire, tensile strength of the deposited metal is 950 MPa to 1500 MPa.

5. The flux-cored wire for welding the ultrahigh tensile strength steel according to claim 1,
wherein a slit-shaped gap does not exist in the outer steel sheath.

6. The flux-cored wire for welding the ultrahigh tensile strength steel according to claim 1,
wherein a perfluoropolyether oil is applied onto a surface of the wire.

7. A welding method using a flux-cored wire for gas-shielded arc welding, the method comprising gas-shielded arc welding a steel plate with a wire, wherein
the wire includes:
an outer steel sheath; and
a flux filled into the outer steel sheath, and wherein the flux comprises:
CaF2, alone or in combination with one or more selected from the group consisting of BaF2, SrF2, and MgF2, wherein a total amount thereof is defined as α, and α is more than 2.0% and equal to or less than 8.0% in terms of mass % with respect to a total mass of the wire,
one or more selected from the group consisting of Ti oxide, Si oxide, Mg oxide, and Al oxide, wherein a total amount thereof is defined as β, and β is 0.01% to 1.20% in terms of mass % with respect to the total mass of the wire,
one or more selected from the group consisting of CaCO3, BaCO3, SrCO3, and MgCO3, wherein a total amount thereof is 0% or more and less than 0.60% in terms of mass % with respect to the total mass of the wire, and
iron powder in an amount of 0% or more and less than 5.0% in terms of mass % with respect to the total mass of the wire,
wherein a ratio of an amount of the CaF2 with respect to the α is 0.50 or more, wherein a ratio of the α with respect to the β is 2.0 to 800.0,
a total amount of an oxides of Na or K or fluorides of Na or K is 0.001% to 0.40% in terms of mass % with respect to the total mass of the wire,
wherein the flux-cored wire comprises C, Si, Mn, Al, Ni, V, P, S, Cu, Cr, Mo, Ti, Nb, B, Mg, Ca, REM, and a remainder iron and impurities, and wherein a total amount of each of these components in an outer skin and the flux, in terms of mass % with respect to the total mass of the wire, is:
C: more than 0.080% and equal to or less than 0.200%,
Si: 0.05% to 1.50%,
Mn: 1.0% to 2.2%,
Al: 0.001% to 0.400%,
Ni: 1.0% to 9.0%,
V: more than 0.050% and equal to or less than 0.300%,
P: 0.020% or less,
S: 0.020% or less,
Cu: 0% to 0.800%,
Cr: 0% to 2.5%,
Mo: 0% to 2.0%,
Ti: 0% to 0.300%,
Nb: 0% to 0.05%,
B: 0% to 0.0100%,
Mg: 0% to 0.8%,
Ca: 0% to 0.5%, and
REM: 0% to 0.0100%, and
Ceq defined in following Expression a is 0.60% to 1.20%,


Ceq=[C]+[Si]/24+[Mn]/6+[Ni]/40+[Cr]/5+[Mo]/4+[V]/14  (a),


in which elements noted in brackets represent amounts of the respective elements in terms of mass %.

8. The welding method according to claim 7,
wherein an amount of CaO in the wire is less than 0.15% in terms of mass % with respect to the total mass of the wire.

9. The welding method according to claim 7 or 8,
wherein the ratio of the amount of CaF2 with respect to the α is 0.90 or more.

10. The welding method according to claim 7,
wherein in a tensile test of a deposited metal which is defined in Japanese Industrial Standards JIS Z 3111-2005 with respect to gas-shielded arc welding using the wire, tensile strength of the deposited metal is 950 MPa to 1500 MPa.

11. The welding method according to claim 7,
wherein a slit-shaped gap does not exist in the outer steel sheath.

12. The welding method according to claim 7,
wherein a perfluoropolyether oil is applied onto a surface of the wire.

13. A manufacturing method for a weld joint,
wherein a tensile strength of the steel sheet is 950 MPa or more in the welding method according to claim 7.

14. A weld joint manufactured by the manufacturing method for the weld joint according to claim 13, the weld joint comprising:
the steel plate having the tensile strength of 950 MPa or more; and
a weld metal.

15. The weld joint according to claim 14,
wherein a tensile strength of the weld metal is 950 MPa or more.

16. The flux-cored wire for welding an ultrahigh tensile strength steel according to claim 1, wherein an amount of CaO in the wire is 0.10% or less in terms of mass % with respect to the total mass of the wire.