US2668336A - Hot top for ingot molds - Google Patents

Description

' INVENToR. .fare/l kurg l/tes .BY 2/ HTTONEY Feb. 9, 1954 J. H. JONES HOT TOP FOR INGOT MOLDS Filed March 6. 1951 Patented Feb. 9, 15954 UNITED STATES NT OFFICE;

2,668,336 l Hor 'roP FOR INGo'r'MoLDs Application March 6, 1951, Serial No. 214,088 4k Claims. (Cl. 2.2-147) This invention relates to mold extensions or hot tops adapted to be positioned on ingot molds and is more particularly concerned with hot tops of the fixed type. having improved design Vto yield a clean smooth surface at the hot top and mold junction of the ingot.

In the production of steel ingots the molds are provided with mold extensions or hot tops which are separate from thernold proper and in the xed type of hot top are positioned on the upper face of the mold. Whenmolten metal is poured into the mold an excess is poured so that the level of molten metal stands above the joint between the mold and the hot top. The excess metal is provided as a reservoir so that as the metal in the mold shrinks on cooling the metal in the hot top can feed down into the mold. A neck portion of the ingot which extends into the hot top after the ingot hardens develops a cavity or pipe in its upper end which results from amore rapid cooling of the outer parts of the ingot. It is customary to remove that part of the neck which has the cavity but an effort is made to save as much of the neck as possible because it contains considerable amounts of sound steel which may be rolled into blooms or billets as a part of the ingot. However, if the joint between the mold and hot top is not tight, ns of metal may freeze in the joint; or, if the opening in the bottom of the hot top is not accurately centered over the mold mouth so as to prevent any extension of the ingot outside of the upper inside corner of the mold, hanger cracks will occur in theingot during solidication. Also, if the hot top isnot centered so as to avoid an excessive shoulder v or step on the ingot by the hot toplower corner extending too far inside ofI the mold opening, a fin or sliver will result when the ingot is rolled.

'between the mold and h ot top was necessary to compensate for expansion of the mold. Such devices have been ineffective and have resulted In addition,if the proper size differential' is not frequently in a shoulder being formed on the ingot of such proportions that a sliver developed on one side, while on the opposite side of the ingot a hanger crack resulted from the hot top extending out beyond the mouth of the mold opening.

An important object of this invention is therefore to provide a hot top which will seal tightly against the upper face of the mold to form a closed joint.

Another object is to provide a hot top construction such that the hot metal in the top will feed readily into the body of the ingot and minimize the/amount of freezing or bridging across.

Another important object is to provide an apparatus which will permit the accurate centering or positioning of the hot top upon the mold, said centering and positioning means beingso designed that the mold and the hot top do not become' bound or rwarped by expansion of the mold during the pouring process. v

Another important object is to prevent the warping of the hot top at the point of contact with the mold by providing adequate means for dissipating quickly heat received at the surface in contact with the mold and the molten ingot.

The invention comprises an improved hot top which may be positioned removably on the upper face of an ingot mold. The hot top has a collar, preferably a single, massive iron casting, which is deiined by an inner and outer wall, a lower end and an upper end. The inner wall is of substantially the same size as the mouth of the ingot mold at the line of contact .between the hot top with the upper face ofthe mold. A mold engaging face is provided on the lower end of the collar and extends from the inner wall of the collar outward a distance less thanthe thickness ofthe collar. .Thev inner wall of the collar is recessedy above the line of contact of the collar .with the mold face to form a ledge. Heat insulating means are mounted on the ledge and slope inwardly toward the upper end to define a cham# ber which is larger at the end adjacent the mouth of the ingotm'old and narrower at the upper end ofthe hot top. Horizontally extending, vertical slots are formed in the lower end of the collar whichV extend in opposite directions outwardly,

- said slots being closed at their inner ends. Pins are fixed in the upper face of the mold and extend upward from said face into the slots at their closed ends, when the hot top is in position -on the upper face of the moldvprior-to the pouring of the ingot, to provide accurate centeringfor the hot top on the mold. For a more complete de- Qasse endV I of the hot top and extends around the perimeter of the mouth l1 of the mold I2. YThe extent of the boss projection I8 from the lower end l5 of the hot top may be, for example, 1/2 so that if the boss surface becomes warped in use, it can be corrected by machine cutting. As indicated, the annular plane face or surface of the boss I 8 is preferably much narrower than the width of the top mold surface i9, both to reduce heat transfer and especially to provide an accurately close iit; for example, where the plane, mold surface l 9 is five or six inches wide or more, the annular surface of the boss may have a width of 21/2 to 3 inches. The excessive weight of the collar Il assists in sealing the joint between the hot top and the mold. The large mass of metal in the collar also provides a dam for temperature and minimizes the possibility of warping of the hot top because heat received from the mold face and molten ingot through the boss I9 is dissipated quickly in the metal mass.

The refractory brick may be made in large shapes, such as the corner shapes 24 and the side or lateral shapes 25 so that by adding or omitting some of the side shapes, lining of this type may be made to fit different sizes of hot tops such as squares and rectangles, providing, of course, that the corner shapes remain standard.

It has been foundthat the use of refractory brick shapes of large extent and considerable mass has resulted in the lining life being extended. Furthermore, by interposing the metal collar, i. e. the ledge 20 and theboss I8 between the refractory lining bricks 24, 25, and the mold face i9 the bricks are not subject to breakage in positioning the hot top and are relieved of the strain of supporting the collar. The sloping walls of the inner face 21 of the refractory brick lining and the wide opening of the hot top adjacent the junction with the mold permits the ingot to settle away from the hot top freely rather than hanging and freezing in the slurry used for an inside dressing of the refractory lining.

The use of hot tops of the type described has resulted in a considerable yield improvement because of the ability to utilize a greater portion of the ingot product whereas previously with the use of conventional hot top ingots objectionable surface conditions at the junction between the hot top and the mold made it necessary to discard steel which was otherwise sound beneath the surface. Mold extensions or hot tops embodying the invention have resulted in achieving the objects sought and produce a superior product at a reduced cost.

In accordance with the provisions of the patent statutes, the principles of this invention have been described together with the best mode of applying those principles; however, it should be understood that the structure disclosed is but one mode of utilizing the invention and the structure described is merely illustrative, for the invention may be carried out by other and alternative means. Also, while it is contemplated to use the various features and elements in the combinations and relations described, some of these may be altered and modified in ways other than those suggested, without departing from the spirit and scope of the invention.

I claim:

l. In combination a hot top and an ingot mold wherein the hot top is removably positioned on the upper surface of the mold, said combination comprising, a collar defined by an inner and an outer wall, a lower end and an upper end, a moldengaging face provided on the" lower end extending from the inner wall outward in a narow perimeter around the mouth of the mold, the inner wall adjacent the lower end defining an opening at least as small as, and no more than slightly smaller than, said mouth, heat insulating means mounted on the inner wall above the mold engaging face, the collar being formed to. define at least two horizontally extending, ver# tical slots extending in opposite directions from the vertical axis of the collar, and opening on the lower end of the collar, each of said slots having at leastv one closed end at its inner extent, pins fixed in the upper face of the mold extending upward from said face and into the slots substantially against their closed ends prior to the pouring of the ingot.

2. The combination of a hot top and ingot mold in which the hot top is removably positioned on the upper surface of the mold, comprising, a massive metal collar of less wall thickness than the ingot mold, said collar having a mold-engaging lower face, an inner wall and an outer wall, said inner wall defining an opening being of substantially the same size as the mouth of the ingot mold at the line of contact of the upper face of the ingot mold with said lower mold-engaging face of the collar, said mold-engaging face extending from the inner wall of the collar outwardly on the mold surface a distance less than the thickness of the collar, heat insulating means on the inner wall of the collar, atleast two lugs on the outer wall of the collar extending outwardly therefrom in opposite directions and formed to deiine horizontally extending, vertical slots, said slots extending outwardly from said outer wall and being closed at the end adjacent said wall, pins fixed in the upper face of the ingot mold and extending upward from said face into the said slots substantially against the closed ends adjacent the said outer wall when the hot top is positioned on the upper face of the mold prior to the pouring of the ingot.

3. The combination of a hot top and an ingot mold in which the hot top may be removably positioned on the upper face of the ingot mold, comprising, a collar having inner and outer walls which are vertical, a lower face and an upper end, a narrow boss extending from the lower face of the collar and adapted to engage the upper face of the ingot mold, said boss extending from the inner wall of the collar outwardly with respect to the mold surface a distance less than the thickness of the collar, said inner wall defining an opening being of substantially the sameV size as the mouth of the ingot mold at the lower face of said collar, heat resisting means disposed on the inner walls of the collar, said heat resisting means having sloping inner walls to deiine an opening which tapers toward the upper end of the collar, and lugs on the outer wall at opposite sides thereof and adjacent the lower face of the collar, said lugs being shaped to deiine horizontally extending, vertical slots having at least one closed end adjacent the outer walls, pins mounted in the upper face of the mold extending upward vertically into said slots substantially against said closed ends thereof when the hot top is positioned on the upper face of the mold prior to the pouring of the ingot.

4. The combination of a hot top and an ingot mold in which the hot top may be removably positioned on the upper face of the ingot mold, comprising, in combination with an ingot mold having a vertical, metal-receiving opening, a col- 1an structure defining an. opening, zaJanui:l aA vertical Wau'dly4 penQverticelvsl'ots, each closed at its. 5

inner end, and upwardly projecting pins carried by lthe mold 'and respeetiuely seating in the slots, s aid. Slots being disposed for engagement of the Closed end. of` each with the corresponding received pin prior to tlie pouring. of metal into the mold, 'and Lsaid collar structure and mold being mutually free lfor outward displacement of the mold@ noon expansion 0i the lather kby the heet qi pouredmetai', to carry, the, pinsA outwadlx in guidedA relation in the A510115 JOSEPH JONES,.-

References Cited in the le of this patent UNITED STATES. PATENTS Number Name. Date m 1,778,316 Forrest'l Oct. 14, 1930 1,792,868 Ramalfgel Feb. 17:, 1931

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