Source: http://www.google.com/patents/US7866706?ie=ISO-8859-1
Timestamp: 2015-07-06 18:22:45
Document Index: 322862582

Matched Legal Cases: ['art 3', 'art 3', 'art 3', 'art 4', 'art 3', 'art 4', 'arts 3', 'arts 4']

Patent US7866706 - Threaded joint for steel pipe - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsA threaded joint for a steel pipe comprises a pin and a box with a contact surface having a threaded part and a unthreaded metal contact part, wherein a solid lubricating film containing one or more kinds of lubricating powders selected from graphite, mica, calcium carbonate and kaolin, a copper powder,...http://www.google.com/patents/US7866706?utm_source=gb-gplus-sharePatent US7866706 - Threaded joint for steel pipeAdvanced Patent SearchPublication numberUS7866706 B2Publication typeGrantApplication numberUS 11/547,067PCT numberPCT/JP2005/006672Publication dateJan 11, 2011Filing dateApr 5, 2005Priority dateApr 6, 2004Fee statusPaidAlso published asCA2563213A1, CA2563213C, CN1938542A, CN1938542B, EP1736697A1, EP1736697A4, US20080277925, WO2005098300A1Publication number11547067, 547067, PCT/2005/6672, PCT/JP/2005/006672, PCT/JP/2005/06672, PCT/JP/5/006672, PCT/JP/5/06672, PCT/JP2005/006672, PCT/JP2005/06672, PCT/JP2005006672, PCT/JP200506672, PCT/JP5/006672, PCT/JP5/06672, PCT/JP5006672, PCT/JP506672, US 7866706 B2, US 7866706B2, US-B2-7866706, US7866706 B2, US7866706B2InventorsKunio Goto, Ryuichi Imai, Yasuhiro Ogawa, Junichi MinamiOriginal AssigneeSumitomo Metal Industries, Ltd.Export CitationBiBTeX, EndNote, RefManPatent Citations (51), Referenced by (2), Classifications (44), Legal Events (4) External Links: USPTO, USPTO Assignment, EspacenetThreaded joint for steel pipe
US 7866706 B2Abstract
A threaded joint for a steel pipe comprises a pin and a box with a contact surface having a threaded part and a unthreaded metal contact part, wherein a solid lubricating film containing one or more kinds of lubricating powders selected from graphite, mica, calcium carbonate and kaolin, a copper powder, and a binder is formed on at least one contact surface of the pin and the box. An object of the present invention is to provide a threaded joint for a steel pipe which allows for repeated fastening and loosening of a threaded joint without adversely influencing on a human body and environment, and is excellent in galling resistance, rust preventing property and gas tightness.
1. A threaded joint for a steel pipe comprising a pin and a box with a contact surface having a threaded part and an unthreaded metal contact part,
wherein a solid lubricating film containing at least: a copper powder of which length of the longest part is 1 to 20 μm; a binder, and one or more kinds of lubricating powders selected from the group consisting of graphite, mica, calcium carbonate and kaolin, is formed on at least one contact surface of the pin and the box,
the copper powder is dispersed in the solid lubricating film,
wherein a surface of the copper powder is inactivation-treated, thereby the copper powder has a copper oxide film, a copper sulfide film, or a film of a metal inactivating agent selected from benzotriazole or thiazole on the surface of the copper powder, and
the solid lubricating film is substantially free from molybdenum disulfide and tungsten disulfide.
2. The threaded joint for a steel pipe according to claim 1, wherein a mass ratio (C/B) of a content (C) of a copper powder to a content (B) of the lubricating powder in the solid lubricating film is 0.5 to 5.0.
3. The threaded joint for a steel pipe according to claim 1, wherein the solid lubricating film is formed on the contact surface of the box.
4. The threaded joint for a steel pipe according to claim 1, wherein the solid lubricating film is formed on only the contact surface of one of the pin and the box, and monolayered or di- or more layered films selected from the group consisting of a zinc or zinc alloy film, a metal plating film, a phosphate film, an oxalate film, a borate film and a rust preventing film is formed on the other contacting surface.
5. The threaded joint for a steel pipe according to clam 1, wherein the solid lubricating film is formed on the contact surface which has been subjected to any undercoating treatment selected from the group consisting of acid washing treatment, blasting treatment, zinc or zinc alloy impact plating treatment, metal plating treatment, soft nitrification treatment, composite metal covering treatment, phosphate treatment and oxalate treatment.
6. The threaded joint for a steel pipe according to claim 1, wherein the solid lubricating film formed on the contact surface is heat-treated.
7. A method of forming the solid lubricating film on the contact surface of the threaded joint for a steel pipe as defined in claim 1, which comprises pre-heating the contact surface on which the solid lubricating film is to be formed. Description
The present invention relates to a screw joint (threaded joint) for a steel pipe which can be used without coating a compound grease which has conventionally been used upon fastening of a threaded joint for an oil well pipe and, at the same time, does not adversely affect on the earth environment and a human body, and is excellent in galling resistance, and a process for manufacturing the same.
In a tubing and a casing used in digging an oil well, a threaded joint is generally used. Usually, a depth of an oil well is 2000 m to 3000 m. However, in a deep oil well such as a marine oil field in recent years, a depth of an oil well reaches 8000 m to 10000 m. An axial tensile force due to a weight of an oil well pipe and a joint themselves and a pressured which is complexed of an internal and external pressure, and heat in the ground exert on a threaded joint for fastening these oil well pipes under the use environment. Therefore, a threaded joint used in an oil well pipe is required to retain gas tightness without damage even under such the environment. In addition, at work of falling a tubing and a casing into an oil well, a once fastened joint is loosened due to a variety of troubles, they are once pulled out from an oil well, and the joint is fastened again, which is fallen.
API (American Petroleum Institute) requires that, even when fastening (makeup) and loosening (breakout) are performed ten times in a tubing joint, or three times in a casing joint, seizure called galling does not occur, and gas tightness is retained. In a threaded joint, usually, a male thread is formed at an end part of an oil well pipe, and a female thread is formed on an internal surface of a threaded joint member. And, by fitting a unthreaded metal contact part formed at a tip of a male thread and a unthreaded metal contact part formed at a base of a female thread, and fastening them, whereby, unthreaded metal contact parts area butted, and a metal seal part is formed. Upon fastening, galling resistance and gas tightness are improved by coating a viscous liquid lubricant containing a heavy metal powder, called “compound grease”. In addition, a threaded part and a unthreaded metal contact part of a threaded joint are subjected to surface treatment for the purpose of improving retainability of a compound grease and improving slidability.
In recent years, based on OSPAR Treaty (Oslo•Paris Treaty), discharge of substances harmful on the earth environment and substances having influence on a human body is being strictly regulated in development of a well of a natural gas and a petroleum. OSPAR Treaty was established by unifying Oslo Treaty and Paris Treaty regarding prevention of marine pollution in 1992, and it was settled that marine environmental protection in Northeast Atlantic Ocean is progressed. In this OSPAR Treaty, an idea of prevention principle is incorporated as general duty of Contracting States, and this is a first framework having a lawful restriction force. OSPAR Treaty was ratified by all countries contacting with Northeast Atlantic Ocean, and came into force in 1998. With progression of such the global strict regulation on the environment, a threaded joint which has no adverse effect on the environment and a human body at fastening of an oil well pipe even in work of digging a gas or oil well, and has excellent galling resistance is sought. The compound grease which has been previously used in a threaded joint upon fastening of a steel pipe for an oil well is being restricted in its use in some areas.
As explained above, a threaded joint which can be repeatedly used without adversely influencing on the earth environment such as marine organisms and human body, and is excellent in galling resistance has not been obtained now.
FIG. 1 is an outline view schematically showing an assembling construction of a steel pipe and a threaded joint member at shipping of a steel pipe.
The present invention is a threaded joint for a steel pipe which does not adversely affect on the earth environment and a human body and is excellent in galling resistance, which comprises a pin and a box with a contact surface having a threaded part and a unthreaded metal contact part, respectively, wherein a solid lubricating film is formed on at least one contact surface of the pin and the box. The present invention will be explained below based on embodiments shown in the drawings.
<1. Assembling Construction of Threaded Joint Member>
FIG. 1 is an outline view schematically showing an assembling construction of an oil well pipe and a threaded joint member at shipping of a steel pipe. A steel pipe A is shipped in the state where a box 2 having a female threaded part 3 b formed on an internal surface of a threaded joint member B is fastened to one of pins 1 having a male threaded part 3 a formed on an external surface of both end parts.
FIG. 2 is an outline view schematically showing a construction of a representative threaded joint for a steel pipe (hereinafter, also referred to as “threaded joint”). A threaded joint is constructed of a pin 1 comprising a male threaded part 3 a, and a unthreaded metal contact part 4 a formed at a tip part, which is formed on an external surface of a steel pipe end part, and a box 2 having a female threaded part 3 b, and a unthreaded metal contact part 4 b, which is formed on an internal surface of a threaded joint member B. Respective threaded parts 3 a, 3 b and unthreaded metal contact parts 4 a, 4 b of the pin 1 and the box 2 are a contact surface of a threaded joint, and this contact surface is required to have galling resistance, gas tightness and rust preventing property. Previously, for this reason, a compound grease containing a heavy metal powder was coated, or a resin film with molybdenum disulfide dispersed therein was formed on the contact surface, but there was a problem on a human body or the environment as described above.
<2. Roughening of Contact Surface>
FIG. 3 shows two aspects of contact surface roughening. It is desirable that, in order to maintain adherability of a solid lubricating film, at least one contact surface of the pin and the box is pre-roughened before formation of a film so that its surface roughness Rmax becomes greater than surface roughness (3 to 5 μm) after machining. In a first aspect of roughening shown in FIG. 3 (a), a steel surface 30 a itself is roughened, and a solid lubricating film 31 a is formed thereon. Examples of such the roughening method include a method of projecting a sand material such as a shot material having a spherical shape and a grid material having a square shape, and a method of roughening a skin by immersing in a strong acid solution such as sulfuric acid, hydrochloric acid, nitric acid and hydrofluoric acid.
Since both of a phosphate chemically treated film and a zinc or zinc-iron alloy film formed by impact plating are a porous film, when a solid lubricating film is formed thereon, adherability of a solid lubricating film is enhanced due to so-called “anchor effect” and, as a result, it is difficult to cause peeling of a solid lubricating film even when fastening and loosening are repeated, contact between metals is effectively prevented, and galling resistance, gas tightness and rust preventing property are further improved. In addition, by forming a solid lubricating film on a porous film, the lubricating component is permeated into a porous film, contributing to improvement in rust preventing property.
Such the particle can be prepared by a method of covering an iron or iron alloy powder as a core with zinc or zinc alloy (e.g. Zn—Fe—Al) by electroless and/or electrolytic plating, and heat-treating this to form an iron-zinc alloy layer on a plating interface, or a mechanical alloying method. As a commercially available product of such the particle, there is Z Iron manufactured by Dowa Iron Powder Co., Ltd., and this can be also utilized. A content of iron or iron alloy in a particle is preferably in a range of 20 to 60% by weight, and a particle diameter of a particle is preferably in a range of 0.2 to 1.5 mm.
<3. Solid Lubricating Film>
(3-1) Lubricating Powder
The solid lubricating film of the present invention is a film containing one or more kinds selected from graphite, mica, calcium carbonate and kaolin which are a powder having no adverse effect on environment and a human body and having lubricating action (hereinafter, referred to as “lubricating powder”), a copper powder, and a binder. It is said that all of these lubricating powders have no or little load on marine environment in Oslo•Paris Treaty (OSPAR).
(3-2) Copper Powder
In the present invention, a copper powder together with the lubricating powder is contained in a film. It is preferable that a copper powder is contained at a specified ratio relative to the lubricating powder and, by such the inclusion, extremely superior lubricating effect is exerted. It is preferable that, as a copper powder, not pure copper itself, but a copper powder which has been inactivated by surface improvement is used. Thus, a solid lubricating film having no or little harmfulness on a human body and the environment can be provided.
(3-3) Binder
As a binder used in the solid lubricating film of the present invention, any of an organic resin and an inorganic polymer compound can be used.
The inorganic polymer compound is a compound having a structure in which a metal-oxygen bond is three dimensionally crosslinked, such as Ti—O, Si—O, Zr—O, Mn—O, Ce—O and Ba—O. This compound can be formed by hydrolysis and condensation of a hydrolysable organometallic compound, a representative of which is metal alkoxide (hydrolysable inorganic compound such as titanium tetrachloride may be used). As metal alkoxide, compounds in which an alkoxy group is a lower alkoxy group such as methoxy, ethoxy, isopropoxy, propoxy, isobutoxy, butoxy, and tert-butoxy can be used. Preferable metal alkoxide is alkoxide of titanium or silicon. Titanium alkoxide is particularly preferable. Inter alia, titanium isopropoxide is excellent in film forming property, being preferable.
(3-4) Each Component Ratio
It is preferable that a mass ratio (B/A) of a content (B) of a lubricating powder to a content (A) of a binder in a solid lubricating film is 0.3 to 9.0. When this mass ratio is less than 0.3, there is little effect of improving lubricating property of a formed solid lubricating film, and improvement in galling resistance is insufficient. When this mass ratio is greater than 9.0, there arises a problem that adherability of a solid lubricating film is reduced, and peeling of a lubricating powder from a solid lubricating film is remarkable. In the case where galling resistance is further required, for example, in the case where an amount of threaded part interference is strict, the mass ratio is more preferably 0.5 to 7.0. In the case where further galling resistance is required as in a high alloy steel, 0.5 to 5.0 is further preferable. In addition, a mass ratio (C/B) of a content (C) of a copper powder to a content (B) of a lubricating powder is preferably 0.5 to 5.0. When this mass ratio is less than 0.5, effect of improving lubricating property of a formed solid lubricating film is small, and improvement in galling resistance is insufficient. When this mass ratio is greater than 5.0, there is fear that an adhering strength of a solid lubricating film and deforming ability of a film are reduced, peeling of a solid lubricating coating film is remarkable, and lubricating effect cannot be maintained during repeated fastening or loosening. From a viewpoint of the reinforcing effect of a lubricating powder and coating property at formation of a solid lubricating film, a mass ratio is more preferably 0.5 to 3.0.
(3-5) Film Thickness
A thickness of a solid lubricating film is desirably 5 μm or larger. A lubricating powder contained in a lubricating film is spread on a total contact surface when undergoes a high surface pressure, and exerts excellent galling resistance. When a thickness of a lubricating film is less than 5 μm, an absolute amount of a contained lubricating powder becomes small, effect of improving lubricating property is reduced, and rust prevention becomes insufficient in some cases. On the other hand, when a thickness of a lubricating film is greater than 40 μm, a problem that a fastening amount becomes insufficient, and gas tightness is reduced due to interference threads, a problem that, when a surface pressure is enhanced in order to maintain gas tightness, galling is easily generated, and a defect that a solid lubricating film is easily peeled are feared, but a solid lubricating film having such the thickness may be used depending on a geometrical shape of a thread. From a viewpoint of reduction in discharge to the environment as much as possible, economical property, galling resistance, and rust preventing property, a film thickness of a solid lubricating film is preferably 10 μm or more and 40 μm or less.
(3-6) Coating
At formation of a solid film, it is desirable to pre-heat a contact surface preferably to a temperature of 50 to 200� C., and coat a coating solution on the surface. Thereby, dripping of a coating solution and ununiformity of a film thickness are reduced, and galling resistance can be further stabilized. When a temperature is lower than 50� C., these effects are small and, when a temperature exceeds 200� C., robust formation of a film is inhibited in some cases. A method of coating a solid lubricating film of the present invention may be according to the known suitable method such as brush coating, immersion treatment and air spraying method.
(3-7) Third Component
Various additives including a rust preventing agent may be added to a solid lubricating film in such a range that galling resistance is not deteriorated. For example, by adding one kind or two or more kinds of a zinc powder, a chromium pigment, silica, and an alumina pigment, rust preventing property of a solid lubricating film itself can be improved. Besides, an oxidation preventing agent, and a coloring agent may be appropriately added in such a range that the object and the effect of the present invention are not deteriorated.
<4. Film Forming Site>
The above-explained solid lubricating film can be formed on a contact surface of one or both of a pin and a box. Since the object of the present invention is sufficiently attained only by forming the film on one contact surface, it is economical to form the film only one of the pin and the box. In this case, work of forming the film is easy in the case of the box.
The present invention will be explained in more detail below by way of Examples. Hereinafter, a contact surface of a threaded part and a metal contact part of a pin is referred to as “pin surface”, and a surface of both of a threaded part and a metal contact part of a box is referred to as “box surface”.
Pin and box surfaces of a threaded joint (external diameter: 17.78 cm (7 inch), wall thickness: 1.036 cm (0.408 inch)) comprising a carbon steel A, a Cr—Mo steel B, a 13% Cr steel C and a high alloy steel D shown in Table 1 were subjected to surface treatment shown in Tables 2 and 3. Formation of a solid lubricating film was performed after a film forming surface had been heated to a temperature of about 50� C. in advance except for Example 10 and Comparative Example 1. Table 4 shows fastening conditions, and Table 5 shows galling and harmfulness on a human body and environment. In addition, rust preventing property was assessed by forming each solid lubricating film on a separately prepared coupon test piece (70 mm�150 mm�2 mm thickness), and performing a wetting test (temperature 50� C., humidity 98%, 200 hours). As a result, it was confirmed that rust is not generated in all Examples.
Ti—O
(1)Ti—O indicates an inorganic polymer compound having a skeleton of Ti—O.
(1) ◯: No occurence of galling, Δ: Slight occurence of galling (galling flaw was repaired, and re-fastening is possible), X: Great occurence of galling (repairing is impossible), —: Not implemented
A threaded joint made of a carbon steel having a composition A shown in Table 1 was subjected to the following surface treatment A box surface was subjected to mechanical grinding finishing (surface roughness 3 μm), and a solid lubricating film having a thickness of 30 μm comprising an epoxy resin containing a graphite powder having an average particle diameter of 5 μm and a copper powder having a maximum length of 15 μm which had been inactivated by surface treatment was formed thereon. A solid lubricating film was a film containing 0.6 of graphite relative to 1 of an epoxy resin, and 1.2 of a copper powder relative to 1 of graphite expressed by a mass ratio. After formation of the solid lubricating film, this was heat-treated at 180� C. for 30 minutes to harden the film. A pin surface was subjected to only mechanical grinding finishing (surface roughness 3 μm). In a fastening and loosening test, a galling did not occur in ten times fastening and loosening in Table 5, being extremely favorable. Of course, it goes without saying that graphite, a copper powder and an epoxy resin in an example of the present invention are harmless on environment and a human body, and discharge into environment is slight as compared with use of the previous grease in Comparative Example 1 described later.
A threaded joint made of a Cr—Mo steel having a composition B shown in Table 1 was subjected to the following surface treatment. A box surface was subjected to mechanical grinding finishing (surface roughness 3 μm), then, a surface thereof was immersed in a manganese phosphate chemical treating solution at 80 to 95� C. for 10 minutes to form a manganese phosphate film having a thickness of 15 μm on the surface, and a solid lubricant film having a thickness of 15 μm comprising an epoxy resin containing a graphite powder having an average particle diameter of 10 μm and a copper powder having a greatest length of 15 μm was further formed thereon. The solid lubricating film was a film containing 1 of graphite relative to 1 of an epoxy resin, and 0.5 of a copper powder relative to 1 of graphite expressed by a mass ratio. After formation of a solid lubricating film, this was heat-treated at 180� C. for 30 minutes to harden a film. A pin surface was subjected to mechanical grinding finishing (surface roughness 3 μm), and immersed in a zinc phosphate chemical treating solution at 75 to 85� C. for 10 minutes to form a zinc phosphate film having a thickness of 15 μm. In a fastening and loosening test, a galling did not occur in ten times fastening and loosening in Table 5, being extremely favorable.
A threaded joint made of a 13Cr steel having a composition C shown in Table 1 was subjected to the following surface treatment. A No. 80 sand was blown to a box surface to adjust surface roughness to 10 μm, copper plating having a thickness of about 5 μm was formed thereon, and a solid lubricating film having a thickness of 20 μm comprising an epoxy resin containing a mica powder having an average particle diameter of 2 μm and a copper powder having a greatest length of 10 μm was further formed thereon. The solid lubricating film was a film containing 2 of mica relative to 1 of an epoxy resin, and 1 of a copper powder relative to 1 of mica expressed by a mass ratio. After formation of the solid lubricating film, this was heat-treated at 180� C. for 30 minutes to harden the film. A pin surface was subjected to only mechanical grinding finishing (surface roughness 3 μm). In a fastening and loosening test, a galling did not occur in ten times fastening and loosening in Table 5, being extremely favorable.
A threaded joint made of a high alloy having a composition D shown in Table 1 was subjected to the following surface treatment. A box surface was subjected to mechanical grinding finishing (surface roughness 3 μm), a porous zinc impact plating of 7 μm was formed by a projection plating method using a particle in which covering is zinc, and a solid lubricating film having a thickness of 30 μm comprising a polyamideimide resin containing a graphite powder having an average particle diameter of 5 μm and a copper powder having a greatest length of 10 μm was formed thereon. The solid lubricating film was a film containing 4 of graphite relative to 1 of a polyamideimide resin, and 2.5 of a copper powder relative to 1 of graphite expressed by a mass ratio. After formation of the solid lubricating film, this was heat-treated at 260� C. for 30 minutes to harden the film. A pin surface was subjected to only mechanical grinding finishing (surface roughness 3 μm). In a fastening and loosening test, a galling did not occur in ten times fastening and loosening in Table 5, being extremely favorable.
A threaded joint made of a Cr—Mo steel having a composition B shown in Table 1 was subjected to the following surface treatment. A box surface was subjected to mechanical grinding finishing (surface roughness 3 μm), then, a surface thereof was immersed in a manganese phosphate chemical treating solution at 80 to 95� C. for 10 minutes to form a manganese phosphate film having a thickness of 12 μm on the surface, and a solid lubricating film having a thickness of 20 μm comprising an epoxy resin containing a graphite powder having an average particle diameter of 10 μm and a copper powder having a greatest length of 10 μm was further formed thereon. The solid lubricating film was a film containing 1 of graphite relative to 1 of an epoxy resin, and 0.5 of a copper powder relative to 1 of graphite expressed by a mass ratio. A pin surface was subjected to mechanical grinding finishing (surface roughness 3 μm), only a threaded part at a pipe end was immersed in a zinc phosphate chemical treating solution at 80 to 95� C. for 15 minutes to form a zinc phosphate film layer having a thickness of 15 μm, and the same solid lubricating film as the solid lubricating film formed on a box was further formed thereon. After formation of the solid lubricating film on both of the pin and the box, this was heat-treated at 180� C. for 30 minutes to harden the film. In a fastening and loosening test, a galling did not occur in ten times fastening and loosening in Table 5, being extremely favorable.
A threaded joint made of Cr—Mo having a composition B shown in Table 1 was subjected to the following surface treatment. A box surface was subjected to mechanical grinding finishing (surface roughness 3 μm), then, a surface thereof was immersed in a manganese phosphate chemical treating solution at 80 to 95� C. for 10 minutes to form a manganese phosphate film having a thickness of 12 μm on the surface, and a solid lubricating film of 40 μm comprising an inorganic polymer compound with a skeleton of Ti—O containing a graphite powder having an average particle diameter of 10 μm and a copper powder having a greatest length of 10 μm was further formed thereon. The solid lubricating film was a film containing 3 of graphite relative to 1 of an inorganic polymer compound with a skeleton of Ti—O, and 0.8 of a copper powder relative to 1 of graphite expressed by a mass ratio. The solid lubricating film was formed by coating a coating solution in which graphite and a copper powder had been dispersed in a solution obtained by titanium isopropoxide in a mixed solvent of xylene:butyl alcohol:trichloroethylene=3:1:3 to have a proportion above in terms of TiO2, allowing to stand this in the air for 3 hours to perform moistening treatment, and blowing the hot air at 150� C. for 10 minutes. A pin surface was subjected to mechanical grinding finishing (surface roughness 3 μm), only a threaded part at a pipe end was immersed in a zinc phosphate chemical treating solution at 80 to 95� C. for 15 minutes to form a zinc phosphate film layer having a thickness of 15 μm, and the same solid lubricating film as the solid lubricating film formed on a box was further formed thereon. In a fastening and loosening test, a slight galling occurred at ninth and tenth completion in ten times fastening and loosening in Table 5, but by repairing, the fastening and loosening was possible until tenth time.
A threaded joint made of a carbon steel having a composition A shown in Table 1 was subjected to the following surface treatment. A box surface was subjected to mechanical grinding finishing (surface roughness 3 μm), then, a surface thereof was immersed in a manganese phosphate chemical treating solution at 80 to 95� C. for 10 minutes to form a manganese phosphate film having a thickness of 12 μm, and a solid lubricating film having a thickness of 15 μm comprising an epoxy resin containing a lubricating powder containing a calcium carbonate powder having an average particle diameter of 12 μm and kaolin having an average particle diameter of 10 μm at the same ratio, and a copper powder having a greatest length of 10 μm was further formed thereon. The solid lubricating film was a film containing a total of 7.5 of calcium carbonate and kaolin relative to 1 of an epoxy resin, and 4.0 of a copper powder relative to a total of 1 of calcium carbonate and kaolin expressed by a mass ratio. After formation of the solid lubricating film, this was heat-treated at 180� C. for 30 minutes to harden the film. A pin surface was subjected to only mechanical grinding finishing (surface roughness 3 μM). In a fastening and loosening test, a slight galling occurred at eighth time or later in ten times fastening and loosening in Table 5, but repairing, the fastening and loosening could be performed until tenth time. This indicates that, when a mass ratio of a copper powder relative to a total of 1 of calcium carbonate and kaolin exceeds 3, a strength of a solid lubricating film is slightly reduced. However, this is a level having no problem as galling resistance performance.
A threaded joint made of a Cr—Mo steel having a composition B shown in Table 1 was subjected to the following surface treatment A box surface was subjected to mechanical grinding finishing (surface roughness 3 μm), then, a surface thereof was immersed in a manganese phosphate chemical treating solution at 80 to 95� C. for 10 minutes to form a manganese phosphate film having a thickness of 15 μm, and a solid lubricating film of a thickness of 15 μm comprising an epoxy resin containing a graphite powder having an average particle diameter of 10 μm and a copper powder of a greatest length of 15 μm was further formed thereon. The solid lubricating film was a film containing a total of 7.5 of calcium carbonate and kaolin relative to 1 of an epoxy resin, and 5.5 of a copper powder relative to a total of 1 of calcium carbonate and kaolin expressed by a mass ratio. After formation of the solid lubricating film, this was heat-treated at 180� C. for 30 minutes to harden the film. A pin surface was subjected to only mechanical grinding finishing (surface roughness 3 μm). In a fastening and loosening test, a slight galling occurred at seventh, eighth and ninth time in ten times fastening and loosening in Table 5, and repairing was performed to continue fastening and loosening, but a great galling occurred at tenth time. This indicates that, when a mass ratio of a copper powder relative to a total 1 of calcium carbonate and kaolin which is a lubricating powder exceeds 5, a strength of a solid lubricating film is reduced as in Example 8. However, this is a level comparable to that of the previous Comparative Examples 1 and 2 as a galling resistance performance.
A threaded joint made of a Cr—Mo steel having a composition B shown in Table 1 was subjected to the following surface treatment A box surface was subjected to mechanical grinding finishing (surface roughness 3 μm), then, a surface thereof was immersed in a manganese phosphate chemical treating solution at 80 to 95� C. for 10 minutes to form a manganese phosphate film having a thickness of 15 μm on the surface, and a solid lubricating film having a thickness of 15 μm comprising an epoxy resin containing a graphite powder having an average particle diameter of 10 μm and a copper powder having a greatest length of 15 μm was further formed thereon. The solid lubricating film was a film containing 1 of graphite relative to 1 of an epoxy resin, and 1.2 of a copper powder relative to 1 of graphite expressed by a mass ratio. Heat treatment after formation of the solid lubricating film was not performed. A pin surface was subjected to mechanical grinding finishing (surface roughness 3 μm), and this was immersed in a zinc phosphate chemical treating solution at 75 to 85� C. for 10 minutes to form a zinc phosphate film having a thickness of 15 μm. In a fastening and loosening test, a slight galling occurred at seventh, eighth and ninth time in ten times fastening and loosening in Table 5, and repairing was performed to continue fastening and loosening, but a great galling occurred at tenth time. This is presumed that since heat treatment was not performed after formation of a solid lubricating film, a strength of the solid lubricating film was reduced as compared with Example 2 of the present invention, and galling resistance performance was inferior. However, this is a level comparable with that of the previous Comparative Examples 1 and 2 as galling resistance performance.
A threaded joint made of a Cr—Mo steel having a composition B shown in Table 1 was subjected to the following surface treatment A box surface was subjected to mechanical grinding finishing (surface roughness 3 μm), then, a surface thereof was immersed in a manganese phosphate chemical treating solution at 80 to 95� C. for 10 minutes to form a manganese phosphate film having a thickness of 15 μm on the surface, and a solid lubricating film having a thickness of 15 μm comprising an epoxy resin containing a graphite powder having an average particle diameter of 10 μm and a copper powder of a greatest length of 15 μm was further formed thereon. The solid lubricating film was a film containing 1 of graphite relative to 1 of an epoxy resin, and 1.2 of a copper powder relative to 1 of graphite expressed by a mass ratio. Upon formation of a solid lubricating film, a contact surface was not pre-heated, but formation was performed at room temperature. A pin surface was subjected to mechanical grinding finishing (surface roughness 3 μm), this was immersed in a zinc phosphate chemical treating solution at 75 to 85� C. for 10 minutes to form a zinc phosphate film having a thickness of 15 μm. In a fastening and loosening test, a slight galling occurred at eighth and ninth time in ten times fastening and loosening in Table 5, and repairing was performed to continue fastening and loosening, but a great galling occurred at tenth time. This is presumed that since upon formation of a solid lubricating film, this was performed without pre-heating a contact surface, formation of a film took a time, a film thickness became slightly ununiform due to dripping. However, this is a level comparable to that of the previous Comparative Examples 1 and 2 as galling resistance performance.
A threaded joint made of a carbon steel having a composition A shown in Table 1 was subjected to the following surface treatment A box surface was subjected to mechanical grinding finishing (surface roughness 3 μm), then, a surface thereof was immersed in a manganese phosphate chemical treating solution at 80 to 95� C. for 10 minutes to form a manganese phosphate film having a thickness of 15 μm on the surface. As a lubricant, a compound grease according to API Standard was coated. A pin surface was subjected to only mechanical grinding finishing (surface roughness 3 μm). In a fastening and loosening test, a galling did not occur until eighth time in ten times fastening and loosening in Table 5. However, at ninth time, a slight galling occurred, but by repairing, fastening and loosening was performed until tenth time to complete a test.
A threaded joint made of a Cr—Mo steel having a composition B shown in Table 1 was subjected to the following surface treatment A box surface was subjected to mechanical grinding finishing (surface roughness 2 μm), then, a surface thereof was immersed in a manganese phosphate chemical treating solution at 80 to 95� C. for 10 minutes to form a manganese phosphate film having a thickness of 15 μm on the surface, and a solid lubricating film of a thickness of a 25 μm comprising a polyamideimide resin containing a molybdenum disulfide powder having an average particle diameter of 5 μm was formed thereon. A solid lubricating film was a film containing 2 of molybdenum disulfide relative to 1 of a polyamideimide resin expressed by a mass ratio. A solid lubricating film of 10 μm comprising an inorganic polymer compound with a skeleton of Ti—O containing a molybdenum disulfide powder having an average particle diameter of 5 μm and a tungsten disulfide powder having an average particle diameter of 3 μm was formed thereon. After formation of a solid lubricating film, this was heat-treated at 260� C. for 30 minutes to harden the film. In a fastening and loosening test, a galling did not occur until sixth time in ten times fastening and loosening in Table 5. However, a slight galling occurred at seventh time, repairing was performed to continue fastening and loosening until ninth time, but a vigorous galling occurred at tenth time.
A threaded joint made of a Cr—Mo steel having a composition B shown in Table 1 was subjected to the following surface treatment. A box surface was subjected to mechanical grinding finishing (surface roughness 3 μm), then, a surface thereof was immersed in a manganese phosphate chemical treating solution at 80 to 95� C. for 10 minutes to form a manganese phosphate film having a thickness of 15 μm on the surface, and a solid lubricating film having a thickness of 15 μm comprising an epoxy resin containing only a graphite powder having an average particle diameter of 10 μm was further formed thereon. A solid lubricating film was a film containing 1 of graphite relative to 1 of an epoxy resin expressed by a mass ratio. After formation of a solid lubricating film, this was heat-treated at 180� C. for 30 minutes to harden the film. A pin surface was subjected to mechanical grinding finishing (surface roughness 3 μm), and immersed in a zinc phosphate chemical treating solution at 75 to 85� C. for 10 minutes to form a zinc phosphate film having a thickness of 15 μm. In a fastening and loosening test, a galling did not occur until fourth time in ten times fastening and loosening in Table 5. However, at fifth time, a slight galling occurred, repairing was performed to continue fastening and loosening until sixth time, but at seventh time, a vigorous galling occurred, and a test was completed.
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pipesUS20080217916 *Feb 29, 2008Sep 11, 2008Shigeo NagasakuThreaded joint for steel pipesJP2001317549A Title not availableJP2002173692A Title not availableJP2002257270A Title not availableJP2003042354A Title not availableJPH0285593A Title not availableJPH0378517A Title not availableJPH0559401A Title not availableJPH0610154A Title not availableJPH0972467A Title not availableJPH05117870A Title not availableJPH05149485A Title not availableJPH08103724A Title not availableJPH08105582A Title not availableJPH08233163A Title not availableJPH08233164A Title not availableJPS6179797A Title not available* Cited by examinerReferenced byCiting PatentFiling datePublication dateApplicantTitleUS8420581 *Apr 30, 2010Apr 16, 2013Nippon Steel & Sumitomo Metal CorporationThreaded joint for pipes having a lubricating coatingUS8758876 *Oct 30, 2012Jun 24, 2014Tenaris Connections LimitedNanocomposite coatings for threaded connections* Cited by examinerClassifications U.S. Classification285/94, 285/333, 285/390International ClassificationC10M103/02, F16L15/04, C10N50/08, C10N40/00, C10M145/20, C10M103/06, C10N10/02, C10M125/00, F16L15/00, F16L15/08, C10N10/04, C10M103/04, E21B17/00, C10M103/00, C10N80/00, E21B17/042, C10M149/18Cooperative ClassificationC10M2201/103, F16L15/006, C10M2201/041, C10M125/00, E21B17/006, F16L15/08, E21B17/042, C10M2201/066, F16L15/001, C10M2201/05, C10M103/00, C10N2240/00, C10N2250/08, C10N2280/00, C10M2201/062, F16L58/182European ClassificationF16L15/08, C10M103/00, C10M125/00, F16L15/00F, E21B17/042, F16L15/00B, E21B17/00M, F16L58/18BLegal EventsDateCodeEventDescriptionApr 4, 2007ASAssignmentOwner name: SUMITOMO METAL INDUSTRIES, LTD., JAPANFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:GOTO, KUNIO;IMAI, RYUICHI;OGAWA, YASUHIRO;AND OTHERS;REEL/FRAME:019115/0625;SIGNING DATES FROM 20060915 TO 20060920Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:GOTO, KUNIO;IMAI, RYUICHI;OGAWA, YASUHIRO;AND OTHERS;SIGNING DATES FROM 20060915 TO 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