US2359321A - Method and composition for protecting ingot molds - Google Patents

Description

Oct. 3, 1944. I UNDEMUTH' 2,359,321

METHOD AND COMPOSITION FOR PROTECTING INGOT MOLDS Filed March 16, 1943 IN V EN TOR. Z; s was BL INDEMQTH;

ATTORNEK Patented Oct. 3, 1944 METHOD AND COMPOSITION FOR PROTECT- ING INGOT MOLDS Lewis B. Lindemuth, Port Washington, N. Y., as-

signor, by mesne assignments, to Steel Ingot Production, Inc., a corporation of Delaware Application March 16, 1943, Serial No. 479,393

Claims.

My invention. relates to a method and composition for preventing ingots from sticking or adhering to the molds in which they are cast.

- When molten steel is poured into an ingot mold the ingot sometimes sticks or adheres to the bottom of. the mold or stool, particularly if the molten steel is poured while at a temperature the mold and ingot must be cooled and the ingot removed'cold and reheated and rolled some later time when similar grades of steel of the'same size are required.

In my present invention the bottoms of the molds or the stools are protected against the sticking or adhering of the poured metal by placing on the bottom of the mold or on the stool a protective coating which does not cause inclusions or enter into or afiect the composition of the steel during or after casting. When a layer of the protective composition is placed at the bottom of the ingot mold, for example, it remains in position and forms a thin protective cushion between the hot molten steel and the metal of the mold bottom or stool.

In my invention I form a protective composition of a mixture of finely ground cork bound together with pitch or pitch-like materials, for example, a coal tar pitch or other bitumen or resin. A small amount of water glass or other combustion retardant may be added to the composition for some purposes, but the composition will consist essentially of finely ground cork and pitch. The cork forms the greater bulk of the composition and the proportions of cork to pitch may vary, depending upon the quality of the cork and pitch, conditions of use, etc.

For example, I have found a mixture of two parts of cork to one part of pitch to be generally suitable for most conditons, although the proportions need not be exact and may vary either way with a greater or less proportion of cork and of pitch respectively.

In applying the composition to the mold the mixture is dropped into the bottom of the mold when the bottom is sufllciently hot to melt the pitch, approximately 350-400 degrees F. The composition thereupon forms a coating on the bottom composed of cork bound together in a matrix of pitch. When the steel is teemed or poured into the mold the cork cushions the impact of the molten steel against the bottom of the mold. The pitch is present in too small a proportion to cause any extensive evolution of flame or smoke or other disturbance in the pouring'and is moreover protected by the cork, which has an insulating effect and which does not contain carbon or any other ingredient in suflicient quantity to alter the composition or quality of the steel. When the steel is poured, therefore, the pitch serves to hold the finely ground cork in position on the surface of the mold while the cork itself, being sluggish in its reaction to heat and very light in density, insulates and protects the bottom of the mold against the impact o1' the molten steel.

Various features of the invention are illustrated, by way of example, in the accompanying drawing in which Figs. 1, 2 and 3 are vertical sections of different forms of ingot molds having the protective coating of my invention covering the bottom or stools thereof.

In Fig. 1 the bottom or stool 5 of an ingot,

- having vertical walls 6, is covered by a layer I of a mixture of finely ground cork and "coal tar pitch. The mixture is placed on the bottom or stool 5 while the latter is sufficiently warm to melt the pitch, whereupon it fuses and forms a binde ormagma for the particlesof cork and spreads through the area of the bottom. The mixture of cork and pitch may be originally formed in any suitable way as, for example, by

. mixing pulverized pitch and cork and either covering the bottom 5 with the mixture in pulverized form, o preparing a sheet of molten pitch and ground cork.

The construction shown in Fig. 2 is similar to that of Fig. 1 having a bottom or stool 8 secured or cemented to side walls 9 covered'with a layer III of pitch and cork. Y a

In the modification shown in Fig. 3 the bottom of the ingot II is formed integrally with the walls thereof and is covered by a layer I2 of pitch and cork mixture. In each case the bottom or stool of the mold is concave or depressed at the center. By spreading or applying the mixture of pitch and cork at the proper temperature of the mold the mixture or layer will adhere firmly to the. surface without flowing to a pool at the center.

What I claim is:

1. A method of protecting ingot molds during pouring which comprises covering the bottom surface of the mold with a composition of pitch and finely divided cork prior to pouring.

2. A method of protecting ingot molds during pouring which comprises covering the surface to be protected with a mixture of finely divided cork and finely divided pitch while the temperature of said mold surface is sufliciently high to melt said pitch.

3. A method of protecting ingot molds during pouring which comprises covering the surface to be protected with a composition comprising a major part of finely divided cork and a minor part of coal tar pitch while the temperature of said mold surface is sufficiently high to melt said pitch.

.4. The method of claim 3 in which said cork comprises approximately two-thirds of said cork go and said pitch comprises approximately onethird thereof.

5. The method of claim 3 in which said composition contains a small quantity of water glass, or other combustion retardant.

6. A composition for protecting the surface of ingot molds which comprises a mixture of finely divided cork and suflicient pitch to cement said finely divided particles of cork.

7. A composition for protecting the surface of ingot molds during teeming which comprises a mixture of finely divided cork and finely divided pitch.

8. A composition for protecting the surface of ingot molds which comprises a mixture of finely divided cork and finely divided pitch in which said cork constitutes the major part of said mixture.

9. A composition for protecting the surface of ingot molds which comprises approximately two parts of finely divided cork and one part of finely divided pitch.

10. The composition of claim 9 in which said pitch is a heat resistant -coal tar pitch LEWIS B. LINDEMU'I'H.

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