Method and apparatus for horizontal continuous casting

A horizontal continuous casting method and apparatus is disclosed. Liquid metal, held in a storage container, is continuously maintained at a height not less than the height of the continuous casting mold. Additionally, adjustment of the relative positions with respect to one another of a magnetic coil surrounding a portion of the continuous casting mold, the storage container, in both the horizontal and vertical directions and the drain pipe extending from the storage container into the continuous casting mold is disclosed.

BACKGROUND OF THE INVENTION AND DESCRIPTION OF THE PRIOR ART 
The invention relates to a method and an apparatus especially advantageous 
for horizontal continuous casting of liquid metals, particularly steel, in 
which the casting metal, flowing in a cooled horizontal continuous casting 
cast-iron mold, is under the influence of gravitational forces of the 
liquid metal contained in the storage container and, furthermore, is 
subject to electro-magnetically produced forces. The electro-magnetically 
produced forces affect the casting metal in the direction of the metal 
strand casting. 
The present invention, by utilizing horizontal continuous casting in 
contrast to the prior art vertical, vertical with a bending mechanism or 
semi-horizontal continuous casting makes unnecessary both bending of the 
cooling metal strand casting from the normal vertical axis into the 
horizontal axis, as well as the expenditure of high finances, incident to 
high building structures normally associated with vertical continuous 
casting. The fully horizontal casting apparatus and process of the present 
invention eliminate all bending forces normally incident to vertical 
continuous casting processes having deflection means after casting. 
A fully horizontal continuous casting method and apparatus, as compared to 
the greater capital expenditure inherent in erecting a structure for a 
vertically arranged continuous casting apparatus, nevertheless has 
heretofore encountered certain technical difficulties which originate, in 
particular, from the horizontal position of the casting strand during the 
cooling period of the casting metal. More specifically, the prior art 
horizontal casting apparatus and methods do not fully eliminate the 
possibility that the hollow space, a result of the pulling off and 
solidification of the casting metal strand, will not be refilled with 
liquid metal. Additionally, conventional horizontal continuous castings 
methods and apparatus cannot insure, in contrast to vertical continuous 
casting methods and apparatus, that the hollow space formed as the liquid 
metal first leaves the water-cooled mold, will be continuously shifted 
into the upper cross sectional area of the casting strand and continuously 
filled. The hollow spaces, if they are not filled in, are subject to a 
certain asymmetry in separating and settling operations and result in 
metal products containing inherent failure possibilities. 
The conventional apparatus for horizontal strand casting evince several 
other disadvantages. For example, conventional horizontal continuous 
casting apparati work on the principle of pulling out the liquid metal 
strand such that the liquid casting metal is continuously replenished in 
the horizontal continuous casting cast-iron mold from the storage 
container. In such apparati the mechanical connection or conduit between 
the storage container and the horizontal continuous casting cast-iron mold 
is always a critical element. Depending upon the specific alloy elements 
of the liquid casting metal and other factors, the casting temperature of 
the liquid metal may be above 1500.degree. C. The occurrence of such 
relative high temperatures in connection with continuously used apparatus 
elements, such as, for example, the storage container, the conduit or 
drain pipe, the horizontal continuous casting cast-iron mold, necessarily 
means that the elements must be easily accessible for potentially frequent 
repair work. The mechanical elements of the conventional horizontal 
continuous casting installations are difficult to repair and/or modify. 
The present invention is extremely simple to repair and/or modify. On the 
other hand, metallurgical requirements do not permit the total 
simplification of the apparatus elements to such an extent that, for 
example, the casting metal is simply guided from the storage container 
into the continuous casting cast-iron mold through troughs open at the 
top. A degree of complexity of apparatus elements is necessarily inherent 
in continuous casting of metallurgical products under tightly controlled 
conditions. The present invention, more fully explained hereinafter, 
accomplishes both of the just mentioned goals in a mutually consistent 
manner, i.e., it is easy to repair and the transfer of liquid metal from 
storage container to mold is not open to the atmosphere. A precisely 
adjustable set of interconnected apparatus elements are provided for 
continuous horizontal casting of metallurgical products which elements, 
however, can be quickly and simply repaired or replaced, as required. 
In German reference DE-AS No. 1,296,747 the suggestion is made to provide a 
horizontal supply line or conduit between a liquid metal storage 
container, from which the supply of liquid metal originates, and the 
horizontal continuous casting cast-iron mold; the conduit being provided, 
around its periphery, with a magnetic pump. The desired purpose of the 
magnetic pump is to maintain a steady pressure of the liquid metal in the 
horizontal continuous casting cast-iron mold. The steady pressure of 
liquid metal in the casting mold produces a high filling content of liquid 
metal in the interior of the horizontal continuous casting cast-iron mold, 
thereby tending to reduce the existence of internal voids in the finished 
metal product. Additionally, the pressure of the liquid metal in the 
horizontal continuous casting cast-iron mold, by being maintained, allows 
the heat exchange between the liquid casting metal and the interior walls 
of the horizontal continuous casting cast-iron mold to be regulated, 
thereby enhancing simplified and more uniform solidification. 
The conventional method of continuous casting of liquid metal operates 
mostly in air-tight conditions so that the negative effects of reoxidation 
of the liquid casting metal is eliminated or reduced. The apparatus 
disclosed in the above identified German reference, by providing a 
horizontal supply conduit between the horizontal continuous casting 
cast-iron mold and the storage container, the conduit being manufactured 
of heat-resistant material, results in a relative high heat loss and an 
unfavorably long travel distance for the liquid metal. The apparatus 
disclosed therein is relatively difficult to adjust while in operation and 
is susceptible to breakdown and other problems. 
SUMMARY OF THE INVENTION 
A specific object sought to be accomplished by the present invention is to 
horizontally cast liquid casting metal, thereby eliminating the known 
disadvantages of vertical continuous casting processes and apparatus. 
Another specific object sought to be accomplished by the present invention 
is the horizontal casting of liquid metal over a short distance between 
storage container and casting mold, thereby substantially eliminating or 
reducing to a minimum heat loss inherent in long supply conduits. Other 
objects of the present invention include the casting of large quantities 
of metal strands per unit time and increasing the degree of filling, i.e., 
reducing voids for horizontal continuous casting for larger mold cross 
sections. An object also sought to be accomplished is the creation of 
structural independence between the liquid metal storage container and the 
horizontal continuous casting cast-iron mold to thereby achieve easy 
adjustability and accessibility. Thus, repair, replacement and 
modification of the horizontal continuous casting cast-iron mold and other 
apparatus elements can be easily accomplished. 
The present invention accomplishes the above described objects by providing 
that the level of the liquid metal in the storage container be 
continuously maintained at least as high as the height of the highest 
point of the inner surface wall of the continuous casting mold cross 
section at its upstream-directed opening. The opening is normally 
maintained in an open position during the casting process. Additionally, 
electro-magnetic forces are provided around the periphery of the 
continuous casting mold by coaxially located magnetic coils. The 
electro-magnetic forces, occurring along the length of the horizontal 
continuous casting cast-iron mold, are continuously, during casting, 
regulated. In this manner, the equilibrium position of the trailing or 
upstream end of the liquid metal, in the open cross section of the 
horizontal continuous casting cast-iron mold, is maintained while the 
casting strand is continuously pulled off in the opposite direction. 
A significant advantage of the present invention resides in the recognition 
that the liquid metal quantity in the storage container counteracts the 
continuous pulling off of casting metal strands, thereby eliminating or 
reducing interior voids in the metal product. Additionally, controlling 
the liquid metal pressure in the longitudinal section within the 
horizontal continuous casting cast-iron mold by the electro-magnetic 
forces simultaneously produces counter-effective forces to the pressure of 
the liquid metal column in the storage container. Even though the 
horizontal continuous casting cast-iron mold, during the casting 
operation, is maintained in an open position at the upstream directed 
opening, it is possible on the basis of the proposed method to supply the 
casting metal in large quantities and in a very simple manner without 
accidental spill-off. Yet, the supply conduit between the storage 
container and the mold is relatively short so that a comparatively 
exacting temperature control gradient during casting can be maintained. 
This is, indeed, a significant improvement over the prior art. 
Furthermore, pursuant to the casting process performed in accordance with 
the teachings of the present invention, the casting metal is not exposed 
to reoxidation, since it is not, during casting, exposed to atmospheric 
oxygen. The inventive apparatus and method allows for relatively 
trouble-free supply of the liquid metal into the horizontal continuous 
casting cast-iron mold. 
Finally, the present invention allows for the near-ideal coordination and 
adjustment of liquid metal pressure, casting velocity and electro-magnetic 
force within the horizontal continuous casting cast-iron mold by having 
various adjustment features. 
The liquid metal pressure within a longitudinal section of the horizontal 
continuous casting cast-iron mold, during the cooling process, can be 
adjusted and maintained by regulating the casting level of liquid metal in 
the storage container at least as high as the height of the inside wall 
surface of the horizontal continuous casting cast-iron mold. 
Alternatively, the bottom level of molten liquid metal in the storage 
container is maintained at a multiple of the cross sectional distance of 
the casting mold above the lowermost height of the inside wall surface of 
the mold. 
In order to further enhance the operating characteristics of the present 
invention, the electro-magnetic forces of the magnetic coil can be 
adjusted higher than the equilibrial force and, consequently, be regulated 
to provide the desired casting velocity. The electro-magnetically produced 
forces counteract the liquid metal pressure within the storage container 
so that the liquid metal flow from the storage container can be increased, 
slowed or completely stopped within desired limits. 
The apparatus for carrying out the method according to the present 
invention basically comprises a liquid metal storage container located 
adjacent to a horizontal continuous casting cast-iron mold; the elements 
being connected together by a relatively short drain pipe. A magnetic coil 
extending around the casting strand axis is also provided. 
The apparatus of the present invention is provided with a horizontally 
extending drain pipe, extending from the storage container and into the 
casting mold. The drain pipe is equipped with a longitudinal section which 
at least in part extends into the horizontal continuous casting cast-iron 
mold. The magnetic coil extends around the casting mold and overlaps at 
least a portion of the longitudinal section of the drain pipe located 
within the horizontal continuous casting cast-iron mold. The apparatus 
thus provides structural independence between the storage container and 
the horizontal continuous casting cast-iron mold, both of which are 
subject to continuous relative adjustability when the apparatus is in 
operation. Furthermore, this arrangement solves, for the first time, the 
problem of the formation and seepage, in an upstream direction, of a 
liquid metal trailing end from the horizontal continuous casting cast-iron 
mold, i.e., the apparatus avoids horizontal leakage of liquid metal from 
the upstream directed opening of the horizontal continuous casting 
cast-iron mold. 
As a further improvement of the apparatus, the magnetic coil can protrude 
or extend beyond the upstream directed opening of the horizontal 
continuous casting cast-iron mold. This feature insures that the liquid 
metal trailing end will not reach the edge of the rearwardly directed 
opening of the horizontal continuous casting cast-iron mold. 
The adjustment of the position of formation of the liquid metal trailing 
end and, simultaneously, the thickness of the formed strand shell at the 
exit of the horizontal continuous casting cast-iron mold is facilitated by 
allowing the magnetic coil to be selectively positioned by being movable 
along the direction of the strand axis. 
The desired magnitude of the magnetic or induction field of the magnetic 
coil in the area located between the inside wall surface of the horizontal 
continuous casting cast-iron mold and the outside wall surface of the 
drain or feeding pipe extending from the storage container, is facilitated 
by the formation of an annular ring-shaped slot existing between the 
exterior of the drain pipe and the interior surface of the horizontal 
continuous casting cast-iron mold. The electrical induction forces are 
advantageously effective since heat, associated with the forces, is 
supplied thereby avoiding solidification in the annular ring-shaped space. 
The ring thus serves as a gasket-type seal. 
The formation of the metal strand shell within the horizontal continuous 
casting cast-iron mold is achieved since the drain pipe has, at least in 
its opening area extending into the casting mold, a tapered outer contour, 
tapering in the downstream direction. This configuration insures that the 
tapered drain pipe will always be surrounded by liquid metal, thereby not 
impairing the formation of solidified zones. 
As a further aspect of the present invention, the storage container is 
selectively adjustable along the upstream and downstream strand axis. The 
relative upstream and downstream adjustability of the storage container is 
in relation to the horizontal continuous casting cast-iron mold. The 
horizontal adjustability of the storage container also allows it to be 
removed quickly from the horizontal continuous casting cast-iron mold or, 
as required, to be replaced immediately prior to the casting process. The 
present invention insures complete independent accessability of both the 
horizontal continuous casting cast-iron mold and the storage container. 
Uniform cooling conditions for the liquid metal are also achieved by the 
fact that the storage container is vertically adjustable. The vertical 
adjustability also allows the level of the liquid metal to be raised to 
the proper height with respect to the casting mold without the addition of 
additional liquid metal. 
Finally, the present invention can be employed for a plurality of 
horizontal continuous casting installations to provide many metal strands 
of simultaneous output. If this is desired, the storage container is 
configured as a distribution vessel for the liquid metal. From there the 
metal is simultaneously directed to many strand casting molds, each of 
which is provided with drain pipes and magnetic coils.

DETAILED DESCRIPTION OF THE INVENTION 
The horizontal continuous casting installation (FIG. 1) is supplied with 
liquid metal, preferably steel, from the casting ladle 1 via its pouring 
nozzle 2. The liquid metal, such as, for example, steel, at a temperature 
of over 1500.degree. C., is received by the storage container 3. The 
closure 4 closes off the drain pipe 13 (see FIG. 2) and selectively serves 
to permit or block the flow of fluid metal into the horizontal continuous 
casting iron-cast mold 5. The casting strand 6 formed within the 
horizontal continuous casting cast-iron mold 5, is extensively cooled as 
it progresses through the cooling zone 7 while being pulled and 
transported by means of the driving structure 8. The driving structure 8 
conveys the cooling metal strand over the roller bed 9 and onto a 
downstream roller bed 10. The cooled metal strand is sequentially cut into 
sectional lengths by means of the flame cutter 11. The sectioned lengths 
of cast metal are directed to a further processing operation by the 
cross-conveyor section 12. 
As best seen in FIG. 2, the storage container 3 is provided with a drain 
pipe 13, extending horizontally into the interior of the horizontal 
continuous casting cast-iron mold 5. The length of the drain pipe 13 is 
inversely proportioned to the quantity of liquid casting metal fed per 
unit time into the storage container 3. Thus, the greater the quantity 
sought to be continuously cast by the continuous casting installation the 
shorter the necessary length of drain pipe 13 extending into the 
horizontal continuous casting cast iron mold 5. Conversely, the smaller 
the quantity desired to be continuously cast by the continuous casting 
installation, the longer the necessary length of drain pipe 13 extending 
into the mold 5. The length of the drain pipe 13, on the other hand, is 
directly proportioned to the specific parameters of the horizontal 
continuous casting cast-iron mold 5. 
Drain pipe 13 is provided with a steadily tapered shape, i.e., its exterior 
surface tapers down toward the downstream direction of the installation. 
The degree of the taper is dependent upon the cooling intensity applied in 
the horizontal continuous casting cast-iron mold 5 and also is dependent 
upon the expected strand-shell formation 6a. The strand formation 6a forms 
an acute angle configuration with respect to the metal strand axis 14. As 
an alternative to the uniformly tapered outer contour 15 of drain pipe 13, 
a stepped taper shape can be provided at the opening area 16 of drain pipe 
13. The drain pipe 13 is preferably manufactured of refractory material 
similar to that which is conventionally used for the manufacture of 
quenching nozzles for the molds of continuous-casting installations. 
The horizontal continuous casting cast-iron mold 5 is made of copper and is 
provided with a water-cooling mechanism (not shown). The mold 5 is 
reciprocatingly moved, i.e., upstream and downstream with respect to the 
entire installation, concentrically with respect to the strand axis 14, by 
means of an oscillating drive 17. The oscillating movement of the mold 
serves to continuously detach the casting strand 6 from the interior 
surface 5a of the mold 5, thereby substantially eliminating ruptures of 
the metal skin within the mold 5. 
An electro-magnetic coil 18 is also arranged concentrically with respect to 
both the metal strand axis 14 and around the horizontal continuous casting 
cast-iron mold 5. The magnetic coil 18 is, in one embodiment of the 
invention, secured to the rigid or oscillating horizontal continuous 
casting cast-iron mold 5 or (as illustrated) it is mounted on a separate 
support frame 19. In either case, the coil 18 and mold 5 are provided with 
the necessary electrical and fluid connections for supplying electrical 
energy and cooling water. 
The magnetic coil 18 overlaps a longitudinal section 20 of mold 5 and also 
overlaps longitudinal section 13a of the drain pipe 13 extending into mold 
5. The concentric longitudinal sections of (a) the magnetic coil 18; (b) 
the continuous casting cast-iron mold 5; and (c) the drain pipe 13, are 
arranged in the context of the present invention, with a degree of overlap 
and practically form an "electric valve", which prevents liquid metal from 
flowing back, i.e., upstream, counter to the preferred direction of 
casting strand flow 21. 
To further insure that liquid metal does not inadvertently escape 
rearwardly through mold 5, the magnetic coil 18 extends by a certain 
length backwardly beyond the rearmost end of the horizontal continuous 
casting cast-iron mold 5 which, during the metal casting operation, is 
open at opening 22. The length of the rearmost extension of the magnetic 
coil 18 can be selectively altered, depending on the location of the 
trailing edge 23 of the liquid metal. To this end, the magnetic coil 18 is 
adjustable by means of cylindrical rollers 24 which ride on a horizontally 
extending track 25. Thus, the magnetic coil is able to move parallel to 
the strand axis 14 in both directions indicated by arrows 26. After proper 
adjustment of magnetic coil 18, the electro-inductive force generated by 
the electrically coupled magnetic coil 18 will be concentrated on the 
annular ring 27 of the liquid metal strand 6 which is formed between the 
inner wall surface 5a of the horizontal continuous casting cast-iron mold 
5 and the outer wall surface 28 of the drain pipe 13. 
Further adjustability of the trailing end 23 of liquid metal strand 6 can 
be accomplished by adjusting the projection of the drain pipe 13 into the 
mold 5. Drain pipe 13, which is directly secured to the storage container 
3, can be horizontally adjusted by movement of storage container 3. As 
illustrated, the storage container 3 is supported on rollers 24 which 
glide on track 29 and is relatively horizontally adjustable, thereby 
adjusting the extension of drain pipe 13 into the mold 5 and magnetic coil 
18 in both of the directions indicated by arrows 26. 
Track 29 for rollers 24 is supported on a hoisting platform 30 which is 
upwardly and downwardly adjustable in both of the vertical directions 
indicated by arrows 32 by means of a hydraulic hoisting drive 31. The 
height adjustability enables the axis of the drain pipe 13 to be centrally 
located on the strand axis 14, i.e., the axes can be coaxially arranged. 
During the metal casting operation, it may be desirable to adjust the 
drain pipe 13 either horizontally with respect to mold 5 or vertically 
with respect to strand axis 14 in order to produce desired flow 
characteristics of the liquid metal within the horizontal continuous 
casting cast-iron mold 5. 
In operation, the continuous casting installation functions as follows: At 
the beginning of the casting process, the exit orifice 5b of the 
horizontal continuous casting cast-iron mold 5 is closed by a conventional 
starting strand cap and sealed by means of sealants. The closure 4 is also 
closed (as illustrated in FIG. 2). Molten metal is then tapped from the 
casting ladle into the storage container 3. As soon as the casting metal 
flows from the casting ladle 1 into the storage container 3 and a casting 
level 33 is established in the storage container 3, the level being at 
least at the height of the uppermost inner surface wall 5a of the 
horizontal continuous casting cast-iron mold 5, the closure 4 is opened 
and the magnetic coil 18 is energized. The trailing end 23 of the metal 
strand 6 is thereby formed. The casting strand 6 is then pulled out by 
means of the driving structure 8, such that the tension is initially 
transmitted to the starting strand. Toward the end of this initial 
production phase, the electrical or induction forces of the magnetic coil 
18 are continuously electrically controlled, depending on the height of 
the casting level 33, thereby preventing backflow of the metal strand. The 
controls for the drive mechanism (not shown) of (a) the storage container 
3, (including drain pipe 13), (b) the magnetic coil 18 in the directions 
26, and (c) hoisting drive 31 in the vertical directions 32 can also, if 
desired, be included in the control of the electrical coil 18. 
As casting continues, the level of the liquid metal in the storage 
container is continuously monitored and adjusted so that it does not fall 
below the height of the uppermost inside wall surface 5a of mold 5. This 
adjustment of the level of the liquid metal can be performed by either 
adding additional liquid metal or by raising the storage container 3, 
being sure, however, not to block the drain pipe 13 by the bottom of the 
storage container 3. 
Alternatively, the level of liquid metal in the storage container 3 can be 
maintained at a fixed multiple, greater than 1, of the cross section 
diameter of the mold 5, above the lowermost inside wall surface 5a of mold 
5. 
It will be appreciated that other embodiments of the present invention can 
be constructed without departing from the teaching of the present 
invention, the invention being defined by the scope of the appended claims 
and equivalents thereof.