US3447772A - Hot top for ingot molds - Google Patents

Description

June 3, 1969 M. D. LA BATE 3,447,772

HOT TOP FOR INGOT MOLDS Filed May 10, 1967 INVENT MICHEAL DONALD LA TE FIG. 6 W/ ATTORNEY FIG. 4 FIG. 5

United States Patent 3,447,772 HOT TOP FOR INGOT MOLDS Michael Donald La Bate, 115 Hazen Ave., Ellwood City, Pa. 16117 Filed May 10, 1967, Ser. No. 637,523 Int. Cl. B22d 7/10; E04b; B65d 7/00 US. Cl. 249-197 4 Claims ABSTRACT OF THE DISCLOSURE This invention relates to a hot top as'used in conjunction with ingot molds to form a heat insulating and heat adding extension at the top of the ingot mold which serves to retain a bath of molten metal at the top of the mold during the freezing of the ingots poured therein. The effect of such a hot top action is to prevent or minimize piping and the formation of other defects in the ingot being poured. The hot top disclosed herein is a consumable hot top and has its principal point of novelty in the shape of the sections forming the same which facilitate its installation in the upper end of an ingot mold at flush or lower settings therein. The 'hot top disclosed herein will when pushed into the mold, force itself against the mold walls to provide a tight fit thereagainst and thus reduce the possibility of fins of metal forming between the hot top and the mold walls. The composition of the hot top can be insulating, exothermic or a combination of both in suitable consumable materials as hereinafter set forth.

One of the characteristics of a consumable hot top is that it will retain the molten metal until the metal chills and sets, whereupon the hot top burns away leaving only an ash residue, thereby eliminating the necessity of removing the hot top from the cast ingot.

In the present invention the four sections of consumable material are so arranged that two of them may be suspended from the sides of the top of the ingot mold and the other two sections of the hot top may be positioned in engagement with the suspended sections so as to be held thereby while the assembled hot top is pushed into the upper end of the ingot mold so that the several parts thereof can form closely to the side walls of the ingot mold. Consumable hot tops heretofore proposed in the art have been ineffective in use, in that they did not always hold the molten metal adequately, and more particularly their use required the molten metal to be within a limited temperature range. The use of the prior art consumable hot tops frequently found the same floating, therefore, ineffective in maintaining a pool of metal on the top of the ingot being poured and at the same time the metal frequently escaped upwardly between the hot top and the inner walls of the ingot mold forming objectionable fins on the cast ingot.

An object of the invention is the provision of a consumable hot top that will effectively receive and hold liquid metal at a temperature as high as 3400. F. while retaining its original shape and physical characteristics, without permitting the liquid metal to escape, so that the metal can solidify normally and maintain a liquid pool which will prevent the formation of piping and/or other irregularities in the cast ingot.

A further object of the invention is the provision of a hot top that is of totally consumable and/or destructive material so that it can be produced and successfully used on ingot molds without regard for the density of metal poured.

The consumable hot top disclosed herein comprises an improvement in the art relating to consumable hot tops, in that a structure is provided that is particularly suited for installation in big end down or big end up ingot molds where the hot top is mounted flush with the top of the mold or at a lower setting relative thereto. In the past such hot tops have fit rather loosely in the ingot mold and permitted the entrance of metal between the hot top and the mold body, thereby forming objectionable fins. The present disclosure provides suitably shaped interengaging sections in a four-part 'hot top that act to forcibly engage one another so as to move the parts into close engagement with the mold body when the hot top is positioned in the ingot mold.

With the foregoing and other objects in view which will appear as the description proceeds, the invention resides in the combination and arrangement of parts and in the details of construction hereinafter described and claimed, it being the intention to cover all changes and modifications of the example of the invention herein chosen for purposes of the disclosure, which do not constitute departures from the spirit and scope of the invention.

The invention is illustrated in the accompanying drawing, wherein:

FIGURE 1 is a perspective view of the hot top.

FIGURE 2 is a plan view of one of the portions of the hot top seen in FIGURE 1.

FIGURE 3 is an end view of top seen in FIGURE 2.

FIGURE 4 is a plan vie-w of the hot top seen in FIGURE 1.

FIGURE 5 is an end view thereof.

FIGURE 6 is a vertical section through an ingot mold with the hot top in position therein and an ingot poured therein.

By referring to the drawings and FIGURE 1 in particular, it will be seen that the hot top disclosed herein comprises two oppositely disposed identically formed side portions 10 and 11 and a pair of oppositely disposed identical end portions 12 and 13 respectively. The side portions 10 and 11 each have eyelets 14 partially embedded therein and extending above their uppermost edges and the marginal ends of the side portions 10 and 11 have inwardly extending slots 15 formed therein, uniformly spaced below the upper surfaces of the sections 10 and 11. The end sections 12 and 13 each have a transversely extending bar 16 embedded therein with the ends of the bar 16 extending outwardly therefrom, as best seen in FIGURE 4 of the drawings. The extending ends of the bar 16 in each of the end sections 12 and 13 register with the slots 15 in the marginal ends of the side sections 10 and 11 as heretofore described. It will be seen that the slots 15 are inclined so that the end sections 12 and 13 are held in position when their bars 16 engaged therein.

By referring now to FIGURES 2 and 3 of the drawings, it will be seen that each side sections 10 and 11 are tapered from their lowermost edges, which are their thickest portions, to their uppermost edges, which are their thinnest portions, and by referring again to FIG- URE 1 of the drawings it will be seen that the end portions 12 and 13 fit between the side portions 10 and 11 so that this taper of the side portions 10 and 11 causes the same to move outwardly as the assembly is pushed into an ingot mold so that the lower edges of the side portions 10 and 11 contact the inner walls of the ingot mold.

It will also be seen by referring to FIGURES 4 and 5 the portion of the hot another of the portions of of the drawings, that each of the end portions 12 and 13 are formed with their upper edges longitudinally wider than their lower edges so that they conform to the reverse taper of the side portions 10 and 11 just described. Additionally, the outer opposite upper sections of the end portions 12 and 13 are relatively thicker as indicated by the numerals 17.

By referring now to FIGURES 1 and 6 of the drawings, it will be seen that when the hot top is assembled and pushed into the upper end of an ingot mold such as M in FIGURE 6, the shape and configuration of the side portions 10 and 11 and the end portions 12 and 13 is such that the portions engage the inner walls of the ingot mold M sufficiently to prevent the entrance of molten metal between the hot top and the side walls of the ingot mold, and the construction thus avoids the fin on a cast ingot which is one of the principal objects of the invention.

By still referring to FIGURE 6 of the drawings, it will be seen that molten metal has been poured into the ingot mold and that the molten metal has risen upwardly into the area of the hot top and formed a liquid pool which will be held for a longer period of time than the liquid metal in the ingot mold M, thereby providing a supply of hot metal to prevent the formation of pipes and cracks and other irregularities in the body of the ingot being cast. After the metal has substantially chilled and set in its peripheral areas within the ingot mold and inwardly thereof, the material of the hot top ignites and is consumed totally, leaving only a powder residue which in no way affects the ingot and on the other hand, provides a ready formed area facilitating the stripping of the ingot from the mold.

Those skilled in the art will observe that combustible hot tops have heretofore been proposed, and they will also be aware of the fact that there are many elements which may be incorporated in a combustible hot top. An example of a desirable mix from which the hot top as disclosed herein may be successfully formed will comprise a batch including 40 pounds of sawdust; 140 pounds of raw dolomite; 80 pounds of sodium silicate as a binder. This basic mixture may be altered by substituting an equal quantity by weight of small sized wood chips, rice hulls or wheat kernels for the sawdust. A still further variation forming a suitable mixture comprises substituting sintered granulated blast furnace slag or finely ground fired cloy (grog) for the raw dolomite in equivalent weight. It has also been determined that a resin urea formaldehyde in an amount of 50 pounds by weight can be used as a binder rather than the 80 pounds of sodium silicate. It will occur to those skilled in the art that a number of variations in the mix of the consumable hot top material therefore are possible. The mix of the consumable hot top may incorporate exothermic materials if desired.

In forming a hot top in accordance with this invention a basic mixture of the above mentioned ingredients is made, for example, of sawdust and sodium silicate and the respective portions 10, 11, 12 and 13 of the hot top are formed by molding the same therefrom. This mixture tends to dry and set and forms a reasonably durable structure capable of the intended use. Its resistance to breakage and crumbling is remarkably increased by baking the same in a hot air oven for a suitable time to thoroughly dry and set the mixture. The portions 10, 11, 12 and 13 may and preferably do, have wire mesh embedded therein to help strengthen the structure and the rods 16 are positioned in the end portions 12 and 13 when the same are formed so that they are suitably embedded therein.

When assembling the hot top in an ingot mold the side sections 10 and 11 are fitted with cross bars engaging the loops 14 which extend from their upper edges, and the same are partially positioned in an ingot mold. The end sections 12 and 13 with their extending rods 16 are then engaged in the marginal slots 15 as heretofore described, and the entire assembly pushed downward into the hot top until the upper edge is flush with the top of the hot top and the wedging action inherent between the shaped portions enables the same to closely engage the inner walls of the ingot mold. The hot top in such position is largely self-supporting as its frictional engagement with the inner walls of the ingot mold hold it in position in addition to closing there areas against the entrance of hot metal which would otherwise form objectionable fins on the cast ingot.

It will thus be seen that a consumable hot top has been disclosed which meets the several objects of the invention, and having thus described my invention what I claim is:

1. A consumable hot top comprising four solid preshaped sections of consumable material arranged in a walled structure having open upper and lower ends, two of said four sections comprising identical side sections, each of which has slots in its marginal ends, the other two of said four sections comprising identical end sections positioned between the opposite ends of said side sections and having rods positioned transversely therein and extending out of their marginal end portions registering with said slots, the lower longitudinal edges of the side sections being relatively thicker than the upper longitudinal edges thereof, the upper longitudinal edges of the end sections being relatively thicker than the lower edge sections thereof, and said end sections have a relatively greater longitudinal length along their upper edges than the longitudinal length of their lower edges.

2. The consumable hot top set forth in claim 1 and wherein said side sections taper from a thin upper edge to a relatively thick lower edge, and said end sections taper from their upper longitudinal edges to their lower edges.

3. The consumable hot top set forth in claim 1 and wherein the marginal ends of said end sections taper from an upper edge to an intermediate point.

4. The consumable hot top set forth in claim 1 and wherein said slots are downwardly inclined, and said side sections include means for holding said walled structure.

References Cited UNITED STATES PATENTS 2,433,803 12/ l 947 Woodworth 249-197 3,318,564 5/ 1967 LaBate 249-197 FOREIGN PATENTS 810,907 3/ 1959 Great Britain.

I. SPENCER OVERHOLSER, Primary Examiner.

R. D. BALDWIN, Assistant Examiner.

US. Cl. X.R.

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