US3163898A - Sealing ring and mat for ingot mold - Google Patents

Description

R. J- DEMAISON 3,163,898

Jan. 5, 1965 SEALING RING AND MAT FOR INGOT MOLD 2 Sheets-Sheet 1 Filed May 6, 1960 D L o M T m mm mm A Jan. 5, 1965 J, DE

SEALING RING AND MAT 2 Sheets-Sheet 2 Filed May 6. 1960 A Ilia United States Patent 3,163,893 SEALKNG RING AND lvlAT FQR HJGOT MGLD Raymond J. Demaison, Bronx, N.Y., assignor to Quigley Company, Inc, a corporation of N ew York Filed May 6, 1960, Ser. No. 27,408 3 Claims. (Cl. 22139) This invention relates to the sealing of molds and stools used in the casting of steel ingots. The composition and methods described herein lend themselves very readily for use on worn stools and molds and provide a longer life for said molds and stools.

In the preparation of molds, stools and hot tops for teeming under the present state of the art, it is possible to do only a minor part of the repairs by the use of equipment, while the major part must be accomplished by hand. In the sealing of a mold and stool that has been badly eroded, the normal procedure is to seal the joint or space by means of a suitable refractory material placed around the outside of the mold, resulting in the forming of ribs or fins in the space not completely caulked. Another problem which arises is that the caulking or sealing is not continuous, or the metal is teerned to fast into the mold, resulting in the metal in the fin not cooling rapidly enough to prevent the pressure of the molten metal pushing out the caulking or sealing compound and thus causing the metal to run out, thereby necessitating the abandoning of the teeming of the mold and the loss of the metal already poured.

So it is easily seen how, under the existing practice, the formation of fins or ribs at the bottom of the ingot cannot be avoided once the mold and stool have become even slightly eroded. This condition does not exist on new stools as the surfaces are flat and therefore fit tightly together, precluding the entrance of the molten metal. But conditions get worse after each pour, as the erosion is the result of teeming, and therefore sooner or later the molds and stools must be replaced with new ones. With this situation in mind, the instant invention was conceived, first, to allow longer life of the molds and stools and, secondly,rto prevent the formation of the ribs or fins on the ingots.

The removal of the ribs or fins is a necessity before further working of the ingot may be accomplished due to the danger of spoiling the complete ingot if worked on with the ribs or fins present. The common practice today is to burn or chip oif the ribs or fins" and then grind the face to a clear even base of the parent metal. It is possible under certain conditions of cooling for the ribs or fins to bind in such a manner in the mold as to result in surface cracks in the ingot due to the forces developed in the ingot upon cooling or, in certain circumstances where the fins or ribs are of suilicient thickness, to crack the complete ingot.

For the foregoing reasons, the existing method of caulking and sealing the molds and stools on the outside periphery has been very unsatisfactory due to the high costs that are involved and the loss of ingots due to leaks or cracks. The end result has been to greatly increase the costs which must be added to the ultimate steel production cost, necessitating a high product price.

Still another one of the problems facing the industry has been the difficulty of obtaining a suitable composition for the caulking and sealing which would not, under the heat of the teemed metal, generate steam and cause gas pockets in the ingot or which, if mixed too wet,

on each ingot.

3,153,898 Patented Jan. 5, 1965 paper fibers mixed together, or kraft paper fibers alone. The widths of the narrow preformed mats should be approximately the same as the thickness of the mold wall. In placing the narrow mats on the stool prior to lowering the mold thereon, care should be taken to locate the mats in such position that their inside faces will be even or flush with the inside face of the mold in lowered position to preclude the forming of ribs or fins. In this disclosure, the narrow preformed mats may also be dipped or sprayed with the insulating refractory material above described to insure perfect sealing of the joints if the stool is very badly eroded.

Still another feature of the present invention is to prevent the splashing of the molten metal in teeming in order to prevent scabbing. The steel as it leaves the nozzle is a liquid with a fluidity approaching that of water so that it is only natural for it to splash up as it first hits the stool or the sides of the mold. In splashing up, the metal may adhere to the sides of the mold and chill and congeal thereon and, since the exposed surface of the metal is immediately oxidized, it will not completely fuse to the main body as the teeming continues and fills the mold. The result is a scab on the ingot which is too thick to remove in the soaking pit and which will therefore have to be removed by chipping. In order to prevent this splashing as well as seal the joint or the space between the mold and the stool, a complete mat of sufficient area of preformed mineral fibers is placed on the stool to completely cover the area of the stool occupied by the mold and so be held in place by the mold as it is lowered thereon. The mats will be precut in size to fit the mold and simply laid upon the stool and will contain sufiicient thickness of the resilient fibers in long form to provide a cushion for the molten metal and thus prevent splashing upon the mold or the erosion of the stool on teeming. One of the mineral fibers that may be used will be basalt wool which is good for temperatures up to 2400 F.

The use of the complete mat disclosed above will, in addition, prevent formation of a chilled shell if the metal is teemed too slowly at the beginning by first preventing the metal from splashing up on the sides and also by insulating the molten metal from the stool and preventing it from chilling too rapidly to preclude a perfect teem In ordinary practice, the metal would surge to flow across the bottom in all directions and up all four sides of the mold and solidify thereon in-; stantly and form a shell. The shell in forming and cooling pulls away from the mold at its upper part and thus presents an open space behind and between it and the mold. Therefore, as the level of the molten metal rises in the mold, it reaches a level where it will overflow and run down into the space and thus produce a disconti-- unity in the skin of the ingot which is actually a fold and is also sometimes called a bootleg. The defect appears as a very scabby section around the ingot and also appears in the mill product made therefrom, necessitating extensive chipping and scarfing in order to remove same.

The addition of the mat at the bottom tends to accomplish another thing besides preventing splashing and that is to control the loss of heat to the stool and thus cause the molten metal to chill and solidify directly from the bottom up, thereby controlling the crystalline structure as well as precluding the formation of cracks or'fissures due to too rapid chilling.

It will now be seen that a new conoep thasbeen advanced by the instant invention in the method of sealing molds and stools. By the practice of the invention, it is possible to prolong mold and stool life, procure ingots without fins or ribs and also preclude blowouts or explosions. The natural result is to reduce costs and save time and still produce a much better product.

' bing.

In the drawings:

FIG. 1 is across sectional view of a typical cast iron or steel mold and stool, very badly eroded, with the mold in place on the stool, and shows the use of a preformed narrow mat of mineral fibers, mineral and kraft fibers, etc., in place to seal the space or crack. The mats are cut or preformed to the width size of the mold wall thickness and placed in position with the mat face substantially flush with the inside face of the mold;

FIG. 2 is a cross sectional view of a typical cast iron or steel mold and'stool, very badly eroded, with the mold in place on the stool, and shows the use of a preformed complete resilient mat of mineralor mineral andkraft fibers to cover the entire area of the stool occupied by the mold, thereby sealing the space or crack and in addition controlling the splash of the molten metal on teeming so as to prevent erosion of the stool and control the flow of heat into the stool and insure controlled chilling of the ingot.

FIG. 1 shows a very badly eroded stool 11 with a wide crack or space'between it and the mold 10. The crack or space is here shown sealed by means of a preformed narrow resilient mat 13 ofmineral wool or mineral wool and kraft fibers placed on the stool and compressed by lowering the mold thereon. These preformed mats or strips 13 are composed of mineral fibers, such as basalt wool (2400 F.) or asbestos fibers (2375 F.) or combinations of the two in various percentages, although if desired kraft fibers may be added to provide greater tear strength to the mats. In placing the narrow resilient mat on the stool, its inside edge is located to be flush with the inside face of the mold when said mold is lowered onto the stool. It is not necessaryto have the mat cut. or formed to the exact width of the mold, as the material may be extended out beyond the outside face of the mold and this will in no way alfect the sealing of the space nor the settling of the mold'on the stool. The material of the mats, being long fibered, is extremely springy and therefore compresses very readily. If it is deemed necessary or desirable, on a very badly eroded stool, the mats may be sprayed or impregnated with a light coat of insulating refractory material and thus insure a complete sealing of the crack. The mats may be preformed in different individual thicknesses or several layers may be laid one upon the other to make up the full thickness.

In FIG. 2 is shown a cross sectional view of a typical cast iron or steel mold in place for teeming on a badly eroded stool 11 with a fairly wide crack or space therebetween. In this embodiment, a complete mat 16 is used to cover the entire area occupied by the mold in its normal teeming position on the stool and not only seals the space between the mold and the stool but, in addition, provides a means for controlling and preventing erosion of the stool as well as, because of its thickness and resiliency, controlling the splashing of hot metal particles up onto the inner surface of the mold to prevent scab- Another factor is that, in covering the entire bottom mold area with a mineral resilient wool mat of sufiicient thickness to prevent splashing, the mat will also control the transfer of heat from the molten mass of steel in the bottom of the mold and thus insure proper chilling of the mold from the outside in and from the bottom up at a proper rate to prevent checks and cracks and thus produce good ingots. Hence this particular embodiment serves to accomplish three very important steps necessary to procure good ingots for better end products at a cheaper cost.

The mold will hold the complete resilient mat in place and prevent its separating and tearing and this is entirely true of basalt wool where the fibers are of sufiicient length to allow the mats tobe formed :by wrapping the s fibers around to form the mat. If the height through which the metal is teemed is excessive, the resilient mat may be covered with a woven mat of the same material and thus preclude tearing because of the excessive speed of the molten metal on striking while still preventing erosion and splashing. In lieu of the mineral wool cover,

a piece of wire mesh maybe placed over the preformed mat to hold the fibers in place and thus prevent excessive tearing.

The mats in this disclosure must be of sufiicient thickness and resiliency to control the splash upon the start of teeming and when the load of the complete ingot has been placed thereon compress evenly to provide a smooth bottom even with the bottom of the mold or a little lower if the stool is badly'eroded. This disclosure may also be used on new stools and molds.

While the invention ha been described in connection with the steel industry, it is not limited thereto, but is intended to cover such variations as are equivalent in composition structure and function.

What is claimed is:

l. A steel ingot mold and stool having a combined seal and cushion to prevent the escape of molten steel from the mold cavity and to control the splashing and the chilling of the teemed metal, said combined seal and cushion being in the form of a preformed mat completely covering the upper surface of the stool within the boundary of the mold cavity and having a peripheral portion sandwiched between the bottom face of the mold and the upper face of the stool, said mat consisting essen-' tially of a dense mass of resilient mineral fibers with its peripheral portion compressed by the weight of the mold and conforming to any irregularities in the opposed faces of the mold and stool.

2. A steel mold and stool according to claim 1, wherein the resilient mineral fibers are basalt wool fibers capable 'of resisting temperatures above 2000 F.

3. A steel ingot mold and stood having a seal to prevent the escape of molten steel from the mold'cavity, said seal being in the form of a preformed mat of substan tially uniform density throughout its sealing area sandwiched between the bottom face of the mold and the upper face of the stool, said mat consisting essentially of a mass of randomly arranged resilient mineral fibers of basalt wool capable of resisting temperatures above 2000" F., said fibers being sufficiently long and sufiiciently free from bonding restraint to impart substantial springiness to the mat and to cause said mat to be compressed by the weight of the mold against the resiliency of said fibers into dense sealing form'and in to sealing conformance with any irregularities in the opposed faces of the mold and stool without-substantial flow of any component of the mat edgewise' of said mat.

References Cited by the Examiner UNITED STATES PATENTS 688,420 Kelly Dec. 10, 1901 1,072,414 Arthur Sept. 9, 1913 1,191,353 Smith July 18, 1916 1,409,040 Thackray Mar. 7, 1922 1,457,763 Adams June 5, 1923 1,613,137 Seigle Jan. 4, 1927 1,859,355 Crowther May 24, 1932 2,324,786 Lindemuth July 20, 1943 2,358,171 Lindemuth Sept. 12, 1944 2,499,729 Daussan Mar. 7, 1950 2,922,206 Schmertz Jan. 26, 1960 2,933,788 Sterick Apr. 26, 1960 FOREIGN PATENTS 248,289 Great Britain Mar. 4, 1926 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No,. 3 162L898 January 5, 1965 Raymond J. Demaison It is hereby certified that error appears in the above numbered patent reqpliring correction and that the said Letters Patent should read as v corrected below Column 1, line 24, for "0" read too column 4 line 1'? for "ha" read has line 38 for "stood" read stool Signed and sealed this 4th day of May 1965.

SEA L) Attest:

ERNEST W. SWIDER Attcsting Officer EDWARD J. BRENNER Commissioner of Patents

Claims (1)

1. A STEEL INGOT MOLD AND STOOL HAVING A COMBINED SEAL AND CUSHION TO PREVENT THE ESCAPE OF MOLTEN STEEL FROM THE MOLD CAVITY AND TO CONTROL THE SPLASHING AND THE CHILLING OF THE TEEMED METAL, SAID COMBINED SEAL AND CUSHION BEING IN THE FORM OF A PREFORMED MAT COMPLETELY COVERING THE UPPER SURFACE OF THE STOOL WITHIN THE BOUNDARY OF THE MOLD CAVITY AND HAVING A PERIPHERAL PORTION SANDWICHED BETWEEN THE BOTTOM FACE OF THE MOLD AND THE UPPER FACE OF THE STOOL, SAID MAT CONSISTING ESSENTIALLY OF A DENSE MASS OF RESILIENT MINERAL FIBERS WITH ITS PERIPHERAL PORTION COMPRESSED BY THE WEIGHT OF THE MOLD AND THE CONFORMING TO AN IRREGULARITIES IN THE OPPOSED FACES OF THE MOLD AND STOOL.

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