US2890504A - Composition for hot top lining - Google Patents

Description

June 16, 1959 R. E. DALEY ETAL COMPOSITION FOR HOT TOP LINING Filed Aug. 14, 1952 INVENTORS ROBERT 5 DALEY BEBEM/AM/IV FAA/590A F/QZ I OD COMPOSITION FOR HOT TOP LlNlNG Robert E. Daley, Broadview Heights, and Benjamin F.

Anthony, Cleveland Heights, Ohio, 'assignors to Oglehay Norton Company, Cleveland, Ohio, a corporation of Delaware Application August 14, 1952, Serial No. 304,234

11 Cl. (Cl. 22-147) The use of hot tops in connection with ingot molds in the casting of metal ingots, such as steel ingots, is wellknown in the art, either the type made entirely of refractory material and intended for a single use, or the composite type comprising a metal casing into which is inserted a refractory lining, usually of suitable brick which are adapted to be used in casting a number of ingots before replacement or serious repair of the lining. Usually all such composite type hot tops, at least with respect to their inner surfaces, are tapered toward the top so as to facilitate stripping or removal of the hot top from the ingot sinkhead.

Referring particularly to the use of composite hot tops, to which reference has been made, it has been common practice to employ a parting compound usually in the form of a slurry which is applied to the inner surface of the refractory lining for the purpose of coating over any roughness of the surface of the lining and to facilitate the stripping of the hot top from the sinkhead of the ingot.

In the case of composite hot tops, for the purpose of gaining improved efliciency, the refractory lining is composed of insulating fire brick, which because of their porous and fragile nature, are subject to damage, either from abrasion during the stripping of the hot top from the sinkhead, or from erosion of the flowing molten metal as it is teemed into the ingot mold, in connection with which the hot top is used, or from other causes. In order to prevent this damage we have employed a heavy coating of a refractory compound, in effect forming a veneer upon the interior surface of the insulating fire brick lining, the veneer being of suificient thickness to protect the brick against damage and also serving the purpose of lowering the face temperature of the lining brick and insuring easy stripping of the hot top from the sinkhead of the ingot.

In all the practices which have heretofore been mentioned, upon removal of the hot top from the sinkhead of the ingot, the slanting walls of the sinkhead do not provide a condition which facilitates the gripping by the jaws of the stripper crane or soaking pit crane tongs, when the same engage the sinkhead to strip the ingot from the ingot mold. The difiiculties involved in the operation just mentioned have at times caused accidents with incident injury to personnel, as well as damage to the soaking pits and adjacent tracks or indeed to the crane itself.

Various ways have been proposed for overcoming the difficulty just recited but so far as we are aware, all the proposed means have involved extra labor and other difiiculties.

We have discovered a way of indenting in an irregular manner and roughening the sinkhead surface thereby to obtain a secure gripping by the tongs of the cranes when the ingot is stripped from a mold or otherwise handled. This is accomplished by incorporating into the compound, used to form the veneer on the inner surfaces of the hot top, a material which upon contact with the heat of Patented June 16, 1959 the sinkhead metal, when an ingot is poured, produces the effect of roughing and indenting in an irregular manner the surface of the sinkhead, to thereby make it more amenable to the gripping action of the crane tongs when the ingot is stripped from the ingot mold.

When the interior lining or veneer for the hot top is composed of suitable proportions of a granular refractory material such as sand and a carbonaceous material such as coke breeze, anthracite silt, sawdust, bone black, together with a suitable plasticizer and binder, and when the hot top is stripped or removed from the sinkhead it is found that the sinkhead surface has, during the solidification of the ingot and sinkhead, pulled away from the lining or veneer and there has been imparted to the surface of the sinkhead an irregular indented portion or portions and in general a roughened surface has been produced.

The foregoing results not only in producing a condition favorable to the effective bite of the crane tongs upon the sinkhead, and so minimizing any opportunity for slippage, but also it is found that the aforementioned veneer has become more or less disintegrated and is easy to remove from the refractory linings of the hot top, all of which facilitates the conditioning of the refractory lining of the hot top to receive a new application of the veneer in preparing the hot top for a subsequent use in casting.

Reference is made to the accompanying drawing in which Fig. 1 is a perspective showing of a sinkhead of a metal ingot showing irregular indentations and roughened surfaces; and

Fig. 2 is a cross-sectional view of a hot top positioned on an ingot mold.

Referring to the drawings, a hot top 10 is shown associated with an ingot mold 11 into which steel has been poured to form an ingot 12 having a sinkhead 13, the hot top comprising an open-ended casing 14 having a refractory lining 15, preferably of insulated firebrick. The lining 15 is protected from the steel in the hot top by veneer 16 of a material which, by reason of its contact with the metal in the hot top, effects a roughening of the sinkhead.

We have found that a suitable composition of matter for use in the manner and for the purpose which has heretofore been described, may be made up of sand or equivalent refractory material together with anthracite silt or coke breeze or sawdust or bone black. A suitable binder must be employed and for this purpose it has been found that many kinds of commercial binders, which are well-known in the art will produce the desired strength. Also in order to produce the desired degree of plasticity, for molding purposes, a moderate amount of bentonite or plastic clay may be incorporated and if it be desired, to enhance the strength of the veneer when finally formed, a moderate amount of asbestos may also be incorporated in the veneer.

The composition is predominantly composed of a granular refractory material of which sand is an example and a carbonaceous material, which is present in appreciable quantity.

One composition which has been found suitable is as follows:

Sand approximately 79% by weight.

Anthracite silt not less than 10% and preferably approximately 15% by weight.

Bentonite 2% by weight.

Binder 1%% by weight, and if desired approximately 2% of asbestos fiber by weight. Another composition which has been found satisfactory comprises:

3 Sand, from 70% to 85%by Weight. Coke breeze, -25% to 10% by weight. Bentonite, 3% by weight. Binder, 1 /2% by weight.

Inutilizingsuch a .composition as disclosed herein, in preparationfor use, the mixture if not sufiiciently moist is combined with enough liquid to produce a plastic or moldable composition and then the composition may be moldedin situupon the inner face of the refractory lining,of the hot top. After application of the material to the refractory lining, the same must be thoroughly dried before use in a casting operation.

It will be apparent .that when the composition. of matter herein disclosed is applied to the inner surface of ahot top it forms essentially a. refractory veneer, anda's suchgives good protection to the other refractory material ofthe hot top. But over and above the feature of protectiontothe hotftop is the fact that when a hot top provided with an inner veneer of the character herein disclosed, is associated with an ingot mold and molten metal is poured through the hot top into the mold and a sufficient amount of metal is within the hot top, the heat of the metal causes the veneer to accomplish a result which is exceedingly useful, to wit: in causing irregular indentations or depressions in a face or faces of the sinkhead and further producing roughened surfaces upon the sinkhead. The veneer .is easily removable from the refractory. lining of the hot top after the hot topis stripped from the sinkhead.

Just what may be the explanation as to why the use of a mixture of; materials such as herein disclosed, causes the phenomenon upon the surface of the ingot sinkhead, is not at the. present time fully understood, but this much has been proven that a similar mixture of materials but omitting the carbonaceous material, while it acts satisfactorily as a protection for the refractory brick or lining'bf'the hot top, does not produce the. surface efiects upon the sinkhead of the ingot, which has been described.

Having thus described our invention, we claim:

1. A moldable composition for molding. in situ a veneer .upon the inner wall of a hot top, consisting principally of a granular refractory material and carbonaceousmaterial togetherwith a binder to make the material moldable, the carbonaceous material forming approximately 10% to 25% of the composition.

2. A moldable composition for molding in situ a veneer upon theinner wall of a hot top, consisting principally of a granular refractory material and coke breeze together with a binder to make the material moldable, the coke breeze forming approximately 10% to 25% of the composition. p i i 3. A, moldable composition for molding in situ a veneerupon the inner wall of a hot top, consisting principally of a granular. refractory material and anthracite silt together with a binder to make the material moldable, the anthracite-silt forming approximately 10% to 25% of the composition.

4. A moldable composition for molding in situa veneer upon the inner wall of a hot top, consisting principally of agranular-refractory material and a carbonaceous material selected from the class consisting. of anthracite silt; coke breeze, sawdust and bone black, the said carbonaceous material forming approximately 10% to 25 of the composition.

5. A moldable composition for molding in situ a veneer upon the inner wall of a hot top, consisting essentially of 70% to 85% by weight of a granularrefractory material and 30% to 10% by weight of a carbonaceous material selected from the class consisting of anthracite silt, coke breeze, sawdust and bone black, together with a binder to make the material moldable.

6'. A moldable composition for molding in situ a veneer upon the inner wall of a hot top, comprising approximately to of a siliceous refractory material; approximately 25% to 10% of coke breeze; approximately 3% of bentonite and approximately 1 /z% of binder.

7. A hot top having a refractory lining and provided with a refractory veneer molded in situ upon the inner face of the hot top lining, said veneer consisting principally of granular refractory material and a carbonaceous material selected from the class consisting of anthracite silt, coke breeze, sawdust and bone black, the said carbonaceous material comprising approximately 10% to 25 of the veneer. I

8. A hot top lined with semi-permanent refractory brick and having a veneer molded in situ upon the inner face of the said brick, lining, said veneer consisting principally of granular refractory material and carbonaceous material, the carbonaceous material comprising approximately 10% to 25% of the veneer.

9. The method of providing a roughened and irregularly indented surface on the sinkhead of a steel ingot which ingot has been cast in an ingot mold equipped with a hot top, which consists in providing a veneer molded in situ upon the inner surface of the hot top which veneer when contacted by the molten metal contained within the hot top after the ingot mold is filled, causes the surfaces'of the ingot sinkhead when solidified to be roughened and irregularly indented, said veneer consisting principally of granular siliceous materal and a carbonaceous material the said carbonaceous material constituting approximately 10% to 25 of the veneer.

10. The method of forming a roughened and irregu larly indented surface on the sinkhead of a steel ingot which consists in providing an ingot mold equipped with a hot top, which hot top upon the inner surface thereof has a' veneer lining consisting principally of granular siliceous material and a carbonaceous material, said carbonaceous material constituting approximately 10% to 25% of the veneer composition, pouring molten metal through said hot top into the ingot mold in suflicient quantity to provide residual molten metal in the hot top which is in contact with said veneer whereby upon the solidification of the-sinkhead a roughened and irregularly indented surface is formed thereon.

11. The method of forming a roughened and irregularly indented surface upon the sinkhead of a cast steel ingot which consists in contacting the molten metal residual in the hot top where the ingot mold is equipped with a hot top, against a veneer lining upon the inner wall of said hot top, which veneer lining is composed principally of granular siliceous material and carbonaceousmaterial, the carbonaceous material constituting approximately 10% to 25% of the composition of the veneer lining.

References Cited in the file of this patent UNITED STATES PATENTS 1,819,364 Firth et a1 Aug. 18, 1931 2,390,500 Charman et al Dec. 11, 1945 FOREIGN PATENTS 15,510 Great Britain Sept. 3, 1898 552,240 Great Britain Mar. 29, 1943

Claims (1)

1. 6. A MOLDABLE COMPOSITION FOR MOLDILNG IN SITU A VENEER UPON THE INNER WALL OF HOT TOP, COMPRISING APPROXIMATELY 70% TO 80% OF A SILICEOUS REFRACTORY MATERIAL; APPROXIMATELY 25% TO 10% OF COKE BREEZE; APPROXIMATELY 3% OF BENTONITE AND APPROXIMATELY 1 1/2%

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