US2852821A

US2852821A - Casting apparatus

Info

Publication number: US2852821A
Application number: US476397A
Authority: US
Inventors: Marvin H Pond
Original assignee: Olin Corp
Current assignee: Olin Corp
Priority date: 1954-12-20
Filing date: 1954-12-20
Publication date: 1958-09-23
Anticipated expiration: 1975-09-23

Description

Sept. 23, 1958 M. H. POND 2,852,821

CASTING APPARATUS Filed 1390.20, 1954 2 Sheets-Sheet 1 INVENTORZ MARVIN H. POND A TTORNEY Sept. 23, 1958 M. H. POND 2,852,321

CASTING APPARATUS Filed Dec. 20. 1954 2 Sheets-Sheet 2 INVENTOR.

MARVIN H. POND ATTORNEY United States Patent Ofifice 2,852,821 Patented Sept. 23, 1958 CASTING APPARATUS Marvin H. Pond, Hamden, Conn, assignor to Olin Mathieson Chemical (:orporation, Alton. Ill., a corporation of Virginia Application December 20, 1954, Serial No. 476,397

11 Claims. (Cl. 22-574) This invention relates to the casting of metal and more specifically to an improved apparatus for continuously casting metal.

One known method of continuous casting of metal and especially in a shape having a width far in excess of the thickness thereof. involves pouring and solidification of the metal between two broad. moving belts; and in apparatus for the practice of this method, it is necessary to provide a suitable side wall structure of a height about the thickness of the strip to be cast to confine the metal at the edges until solidification occurs. I-leretofore, various side walls have been tried. A stationary side wall structure, for example, is one type which has been tried, but poor operation has resulted largely because of the frictional resistance presented by this type of side wall to the metal being shaped. To overcome this problem moving side walls of various type: including laminated walls have also been tried; but penetration by the molten metal and undesired welding between the s and the metal being cast have prevented the suc.. sful ado tion of such structures and any worthwhile rcution of the potential advantages of endless belt casting lTl'rlChillS. Most of these prior types of side wall structures have been further characterized by inubitity to adjust to variation in belt spacing and by diszulvantageous heat conductivity for the successful casting of metal in the shape of a thin slab or strip. Specifically a disadvantage of these prior art mold side walls has been the difliculty of obtaining an operable fit at the edges of the broad moving casting belts adjacent the side walls and especially the type of fit necessary to prevent the escape of molten metal between the belt and side wall and to avoid the resultant inferior performance whenever excessive flash. for example, is formed by the escaping metal.

Therefore, one object of this invention is to overcome the aforementioned ditlicultics by provision of a side wall of novel construction. Another object is to provide improvements in a moving belt type continuous casting apparatus suitable for production of metal strip and the like. Other objects and the advantagesv this invention will be apparent from the following deacrlption and the accompanying drawing in which:

Figure l is a sen'lidiagrammatic elevational view showing a typical moving belt type of continuous casting machine having side walls in accordance with this invention;

Figure 2 is a cross-sectional view taken on line ll-ll of Figure 1;

Figure 3 is a perspective view of a. part of one preferred embodiment of the side wall of this invention with an end shown in cross-section.

Figure 4 is a perspective view of a part of another embodiment of the ide wall with an end shown in crosssection.

In accordance with this invention, there is provided, in a casting apparatus, compressible mold walls or an edge dam made up of a bundle of refractory fibers or strands and specifically of asbestos thread or twine. The asbestos preferably is woven to form a fabric or sheet interwoven with metallic strands and more specifically with thin flexible wire forming a reinforcing core in some and preferably all of the asbestos thread or twine. This sheet is laid up to form a laminated body, the plies of which are secured in any suitable way such as by stitching but preferably by stitching with a metal, asbestos, or other refractory strand. Thus by means of this: invention there is provided a flexible, compressible, and preferably reinforced, refractory edge dam or mold side Wall structure characterized by the ability to adapt itself to such spacing and spacing variation as normally occurs in the belt casting machine. The side wall surface of this structure presented to metal being cast is capable of bearing and taking up a suitable mold dressing compound in a satisfactory manner. But the side wall structure as such is capable of satisfactorily containing molten metal without a coating of any kind.

The compressible asbestos side wall structure is fibrous and preferably porous so that whenever mold dressing is specified, it is also adapted to pick up the mold dressing material in a desirable way. The fibrous side wall is not only compressible but also resilient to an appreciable extent so as to substantially resist early packing down and the resultant loss of porosity and compressibility. By porosity is meant the presence of interstices which enhance the compressibility of the side wall and facilitate the application of mold dressing to the side wall structure. When compressed between face plates or belts of various types of casting apparatus, the side wall structure of this invention provides a satisfactory mold wall. A suitable mold dressing may be readily applied as desired to alter the heat abstraction characteristics of the walls to suit the particular metal being cast or the particular casting apparatus in which the side wall is being used.

For continuous casting apparatus of the kind described, the side wall is in the form of an endless belt constituted largely of asbestos strands or fibers. Preferably the endless edge dam structure of this invention takes the form of a single convolutely wound piece of asbestos tape or ribbon secured together as lamina of the structure. How ever, the laminated structure may be formed of a plurality of pieces of ribbon or tape secured together in any suitable manner.

The preferred embodiment of the edge dam found to produce satisfactory operation of the belt type casting machine described consists of an endless, flexible, wirereinforced, woven asbestos tape of suitable Width plied up to desired thickness and bound together by stitching with asbestos fiber cord or metallic thread to form a laminate. To the surface of this compressible mold wall there is applied usually a substantially heat resistant dressing at the surface exposed to the metal in the process of being cast. The laminated mold side wall structure of this invention may also be impregnated throughout with a refractory parting and mold dressing material such as one including graphite or the like. A suitable dressing, especially for casting of aluminum, is one made up of a silicone, silica gel and graphite. Other dressings and parting compounds suitable for the casting of metal may, however, also be used such as colloidal graphite in lard oil and the like. A suitable silicone for the purpose is dimethylpolysiloxane. The nature of the dressing however, is not of importance since its use and its type is purely optional with the casting machine operator.

The invention will be better understood from and illustrated but not limited by a reference to the rather diagrammatic representation of Figures 1 and 2 of a continuous casting machine in which 1 and 2 each refers to an endless side wall or edge dam belt of this invention adapted to be sandwiched between endless broad metal mold face belts or

bands

3 and 4 at the lateral edges thereof. Side walls 1 and 2 are carried along on and adjacent the lateral edges of belt 3, which in turn is supported on and passes around end rolls and 6. The other main casting or mold face belt 4, which like belt 3 is made of a strip of suitable metal such as stainless steel. is carried over another pair of

end rolls

7 and 8. As shown in Figure 2, belt 4 overlies belt 3 and in the casting area of the

machine belts

3 and 4 pass in closely spaced parallel relationship. Side wall belt 1 is carried about belt 3 at one side of the rolls 5 and 6 while side wall belt 2 is carried at the other side oi" rolls 5 and 6 about belt 3. in this casting area, the lower mold face belt 3 is backed up by a series of rolls 9 and upper mold face belt 4 is in turn backed up by a series of rolls 19. As assembled in operative relation ship in the casting area of the machine, side belt 1 forms the edge dam 11 and belt 2 forms the edge darn ll f the casting cavity 13 of rectangular cross section defined by the

mold face belts

3 and 4 and the edge dams 1i and 12. At the masting cavity 13 the lateral edges of

face belts

3 and 4 are pressed at intervals against the edge dams El and 12 by any suitable instrumentalities such as the series of support rolls 9 and the ends of which arc forced against the back side of the lateral edges of the

face belts

3 and 4 so as to squeeze

belts

3 and 4 against the compressible edge dams 11 and 12, which are backed up by guide bars 14 and 15, respectively. Side belts 1 and 2 and

face belts

3 and 4 are driven by any suitable mechanism to move with the casting 18 as it traverses the cavity 13.

In operation molten metal from reservoir or crucible 16 is supplied to the tundish 17 which feeds a stream of metal at a desirable flow rate into the cavity 13 in which solidification of the metal occurs to produce the relatively broad thin slab 13. To aid in solidifying the metal.

belts

3 and 4 may be subjected to a stream of coolant.

The side wall or edge dam structure according to the specific embodiment of Figure 3 consists of layers of asbestos ribbon or tape 19 having wire reinforcing 20 longitudinally or in the direction of the length thereof and which is bound together by parallel rows of stitching 21. The asbestos tape 19 is woven from asbestos thread of a diameter of about 0.0625 of an inch, for example, into which is twisted flexible metallic strands 20 each of a diameter of about 0.008 of an inch and made up of any suitable metal such as copper, brass, steel or the like. The tape 19 is plied up to a suitable thickness to form the multiple layer endless edge darn structures 11 and 12, all the layers of which are secured together by stitching with asbestos yarn 21. To form endless side wall belts 1 and 2, tape 19 may be convolutely wound and then secured by the yarn or strand 2].

For the obtainment of maximum compressibility, this type of edge dam is installed so that the lateral edges 22 of the layers are presented to and confine the molten metal. Where the temperature conditions so require, a mold dressing material is applied to the face made up by the contiguous edges 22 so that at least this face carries dressing.

The metal casting mold side wall of this invention may also take the form illustrated in Figure 4, wherein the asbestos cloth 23, as in the previous embodiment, is firmly reinforced and supported by metallic strands 24 and is further impregnated, if desired, with a silicone compound such as one consisting of dimethylpolysiloxane, or with colloidal graphite or silica gel particles. In this embodiment the sheet or fabric is convolutely wound laterally from both lateral edges so as to make up a plurality of layers. For a belt type continuous casting machine the structure illustrated in Figure 4 may consist of a single continuous wide loop or ring of such asbestos fabric or sheet convolutely wound laterally to present the narrow compressible multi-layer structure shown. It may also be formed by a convolutely wound wide tape given secondary convolute turns to reduce the width and increase the number of layers of asbestos sheets in the finished endless side wall. Where necessary,

according to the dictates of the heat released, the mold dressing material is applied to the face 25, which is next to the metal. so that at least this face carries dressing.

Beside these two embodiments others can be made. For instance wire reinforced asbestos strand can be laid in parallel to make a bundle which may be enclosed in woven asbestos tubing.

One big advantage secured by this invention lies in the fact that the plied up refractory fabric structure coated with and even to some extent impregnated with a suitable dressing provides a desirably high degree of compressibility of one unit enabling a positive seal to be made between the two broad casting belts of the machine thereby preventing any leakage of molten metal. The prior art moving edge dams have been difficult to control because of their incompressible construction. With the side wall construction described herein it is also possible to attain a low value of heat conductivity which under some circumstances is desirable to prevent abstraction of heat at the lateral edges of the shape being cast. It will be appreciated that friction between the casting and the edge dam is not a factor in this type of side wall structure. Another advantage secured by this invention is that when the compressible endless side wall structure is impregnated with a flowable mold dressing, as the wall enters the bite of back-up rolls disposed along the main casting belts and is compressed there is automatically exuded a fresh layer of dressing at the surface exposed to the metal being cast at times desired in the casting process.

While the invention has outstanding utility in the art of continuous casting with respect to which it has been described herein, it will be understood that it has utility with any metal casting apparatus such as the permanent metallic type of two part book mold.

Since many other embodiments may occur to those skilled in the art, it is to be understood that the foregoing is intended by way of illustration and not as a limitation of the scope of the present invention except as set forth in the appended claims.

What is claimed is:

I. In combination with machine for continuously casting wide thin shapes from molten metal having a pair of elongated moving casting bands of metal traveling in the same direction and at least over part of their travel in spaced facc-tofacc relationship. a compressible mold side wall at each opposed pair ofgthc lateral edges of said bands, said side walls consisting of multiple layers of asbestos fabric interwoven with metallic strands and directly facing the molten metal.

2. In combination with a machine for continuously casting wide thin shapes from molten metal having a pair of elongated moving bands traveling in the same direction and at least over part of their travel in spaced face-toface relationship, a compressible mold side wall at each opposed pair of the lateral edges of said bands, said Wall consisting of a bundle of asbestos fibers and metallic strands and directly facing the molten metal.

3. in combination with a mach ne for continuously casting wide thin shapes from molten metal between a pair of clongated moving broad metal bands traveling in the same direction and at least over part of their travel in spaced face-to-fnce relationship. a compressible mold side wall comprising a moving belt etween each opposed pair of the lateral edges of said bands. of flexible asbestos sheeting and metallic straruls. said sheeting and strands running in the direction of the length and travel of said side wall and directly facing the molten metal.

4. ln apparatus for the casting of metals. a molten metal pressure retaining mold wall comprising a com pressible bundle consisting essentially of a contiguous plurality of strands laid up so as to each extend substantially continuously in the longitudinal direction in said mold Wall transversely to the direction in which said molten metal pressure is exerted in said wall and with limited mobility with respect to each other in said wall under a mold wall compressive force applied transversely both with respect to said longitudinal direction and molten metal pressure direction.

5. The apparatus of claim 4 wherein the strands consist largely of asbestos.

6. The apparatus of claim 5 including metallic strands interwoven therewith.

7. The apparatus of claim 4 wherein the strands comprise asbestos tape assembled in layers stacked together in the direction of the compressive force and with one set of contiguous lateral edges of said tape assembly facing in juxtaposition with respect to the molten metal.

8. The apparatus of claim 7 wherein the asbestos is in the form of a compressible woven fabric tape extending longitudinally with metal wire reinforcing interwoven in the tape.

9. The apparatus of claim 8 wherein the layers of tape are all secured together.

10. The apparatus of claim 7 wherein the tape is convolutely wound at least in one of the longitudinal and transverse directions to be plied up to form a mold side wall element of substantially rectangular cross-section to a heighth substantially l.l excess of the compressed heighth in said side wall.

ll. The apparatus of claim 10 having metallic strands interwoven in said tape in the longitudinal direction.

References Cited in the file of this patent UNITED STATES PATENTS 1,108,693 Burkhardt Aug. 25, 1914 2,193,429 McConnell Mar. 12, 1940 2,230,27l Simpson Feb. 4, 1941 2,372,673 Jacob Apr. 3, 1945 2,489,322 Olsen Nov. 29, 1949 2,496,279 Ely et al. Feb. 7, 1950 2,554,548 Albagnac May 29, 1951 2,676,369 Stark Apr. 27, 1954 FOREIGN PATENTS 575,734 Great Britain Mar. 4, 1946 383,313 Italy Oct. 2, 1940