US3015139A

US3015139A - Sectional hot top

Info

Publication number: US3015139A
Application number: US849337A
Authority: US
Inventors: Marburg Edgar
Original assignee: United States Steel Corp
Current assignee: United States Steel Corp
Priority date: 1959-10-28
Filing date: 1959-10-28
Publication date: 1962-01-02
Anticipated expiration: 1979-01-02

Description

Jan. 2, 1962 E. MARBURG SECTIONAL HOT TOP 4 Sheets-Sheet 1 Filed Oct. 28, 1959 INVENTOR. EM M43066 ATTORNEY INVENTOR..

4 Sheets-Sheet 2 E. MARBURG SECTIONAL HOT TOP Jan. 2, 1962 Filed Oct. 28, 1959 Jan. 2, 1962 E, MARBURG SECTIONAL HOT TOP 4 Sheets-Sheet 5 Filed Oct. 29, 1959 INVENTOR- 96.41? M448UQ6 BY ATTORNEY Jan. 2, 1962 E. MARBURG SECTIONAL HOT TOP 4 Sheets-Sheet 4 Filed Oct. 28, 1959 IIVVE/VTGIQ BY 06441? MAQEUQG 3,015,139 SEUTHUNAL HUT TGP Edgar Marburg. Pittsburgh, Pa, assignor to United States Steel Corporation, a corporation of New .lersey Filed (let. 2%, i959. Ser. No. 849,337 6 Claims. (Cl. 22147) This invention relates to a sectional hot top and more particularly to such a hot top for use in an ingot mold.

Hot tops most commonly used for casting steel ingots are the one-piece variety. However, one-piece hot tops have definite disadvantages, one of which is that they cannot closely fit the walls of the ingot mold since the hot top must clear scrap that may adhere to the top of a mold of the minimum opening for a given size of ingot and the molds will generally be larger than this size. Therefore, the hot top is commonly made /2 to inch smaller than the mold opening. As a result liquid metal may rise between the mold and the hot top to form metal fins, which may flare out during rolling and damage mill guides. These fins also entrap portions of the clay hot top, which explode during rolling and propel brick particles with considerable force to the hazard of personnel in the vicinity of the mill. Because of the disadvantages of a one-piece hot top, sectional hot tops have been produced and have had limited use. However, the sectional hot tops of which I have knowledge have proved unsatisfactory for various reasons. They may be difficult to manufacture and/or install, they may be weak structurally, they may not contact the mold wall closely enough to prevent metal from getting therebetween, the joints between the parts of the hot top may sometimes allow metal leakage, the hot top pieces may vary in level to such an extent that it may not be possible to pour sufiicient metal to obtain a sound ingot, and the height to minimum width ratio of the hot top opening may not be the best for efficient utilization of the metal in the sinkhead. With al of the hot tops of which I have knowledge the ingot weight will vary when the internal dimensions of the mold vary from those specified.

It is therefore an object of my invention to provide a sectional hot top with good structural strength which will closely contact all four walls of the ingot mold.

Another object is to provide such a hot top that is adapted to be readily installed in an ingot mold.

Still another object is to provide such a hot top which will produce an ingot of approximately the specified weight regardless of normal variation of the mold opening, substantially free from metal fins and from refractory contamination, and of sound internal quality.

These and other objects will be more apparent after referring to the following specification and attached drawings. in which:

FIGURE 1 is a top plan view of an assembled hot P;

FIGURE 2 is an elevation, partly in section, of the hot top assembled on an ingot mold;

FIGURE 3 is a view taken on the line III-III of FIGURE 1;

FIGURE 4 is a bottom view of the assembled hot top;

FIGURE 5 is an elevation of the end slab of the hot top taken from the mold side;

FIGURE 6 is a top plan view of the end slab of FIG- URE 5;

FIGURE 7 is an end elevation of the end slab of FIG- URE 5;

FIGURE 8 is a fragmentary elevation of the end slab taken from the side opposite FIGURE 5;

FIGURE 9' is a fragmentary bottom view of the end slab;

FIGURE 10 is an elevation of the side slab of the hot top taken from the mold side;

Patented Jan. 2, 1962 FIGURE 11 is a top plan view of the side slab of FIGURE 10;

FIGURE 12 is an end elevation of the side sbab of FIGURE 10;

FlGURE 13 is a fragmentary elevation of the side slab taken from the side opposite FIGURE 10; and

FIGURE 14 is a fragmentary bottom view of the side slab.

Referring more particularly to the drawings reference numeral 2 indicates the top of a mold on which a hot top is positioned. The hot top consists of a pair of end slabs d and a pair of side slabs 6. Each of the end slabs includes a generally vertical portion 8 and a generally horizontal portion 16' extending outwardly from the bottom of portion 8. The outer face of the portion 10 is shaped to contact the mold wall. End faces 12 of each of the end slabs are connected by an arcuate inner face 14 which is shown as a circular arc. The inner periphery of the vertical portion 8 is narrower than its outer periphery so that the end faces 12 diverge outwardly from the inner to outer faces at an angle of substantially 45. Each of the end faces has a triangular projection 18 thereon that extends parallel to the inside edge of the end face. Each of the faces 12 including the triangular projection Eli; tapers downwardly at a uniform taper toward the opposite end face for the majority of its length and then at a greater taper 20 to the bottom of the slab. A generally vertical slot 22 which is arcuate in plan extends from the bottom of the slab upwardly to an opening 23 below the top thereof. An exothermic layer 24 is preferably provided in the slot 22 and opening 23. Alternatively an exothermic insert may be placed in the bottom portion of the slot only, with an open slot or a layer of combustible material such as corrugated cardboard (with the corrugations vertical) above it, and with no opening to the inside face in the top portion. Vent holes 26 extend outwardly from the slot 22 to the outside of the slab. A lifting pocket 28 is provided in the bottom of the slab. The outer wall of the slab is preferably arcuate at 39 for a purpose to be described later.

Each of the side slabs 6 has an outer face 32 adapted to contact the mold wall and an arcuate inner face 34 of the same radius as the inner face 14 of the end slab. The inner periphery of the slab 6 is narrower than its outer periphery so that end faces 36 diverge outwardly from the inner to outer faces at an angle of substantially 45. Each of the end faces 36 has a generally vertical triangular groove 38 therein of the same size and shape as the projection 18 on the end piece 4. Each of the faces 36 including the groove 38 tapers downwardly away from the opposite end face for the majority of its length and changes to a greater taper 40 at the bottom thereof. The

tapers

20 and 40 have the same slope but the taper 2% is preferably shorter than the taper 40. For example, I have found that the taper 20 is preferably four inches long and the taper 40 six inches long. A lifting pocket 42 is preferably provided in the bottom of the slab. The outer face of the slab 6 is recessed slightly at 44 between a top flange 46 and a base portion 48. The purpose of depressing face 44 below the base portion 48 is to permit tapered slots (49) to be provided at the top of base portion 48 on either side so that wood wedges contacting the recessed face 44 may be driven between the hot top and the mold. Vertically spaced

grooves

50 and 52 are provided in the outer face of the slab 6 below the flange 46. An arcuate generally vertical slot 54 is provided in the slab 6 and extends from the bottom thereof upwardly to an opening 56 below the top thereof. Exothermic material 58 is preferably provided in the slot 54 and extended to the inside face in the opening 56. Vent holes 61: are provided in the slabs 6 from the slot 54 to the outer face of the slab. Holes 62 are provided in the o outer face of slabs 6 for a purpose which will appear later. Notches 6- and 66 may be provided in the top of slabs 4 and 6, respectively, to aid in centering the slabs of the hot top in an apparatus provided for installing the hot top in the mold by crane.

In installing the hot top in a mold, rods -58 are first placed in selected holes 62 of the two side slabs 6, and these slabs are lowered into the ingot mold 2 until the rods 68 rest on the top of the mold. The end slabs 4 are then inserted with the ridges l3 inside the grooves 38, and the slabs are allowed to drop downwardly with the faces 16 and 36 forcing the slabs outwardly against the mold walls. Wires 7% are placed around the top of the slabs in grooves 5t? and 52 and around the matching curves 30 of the end slabs 4 after which they are tightcried and their ends fastened together near the middle of the near end slab to hold the tops of the slabs together. Wood Wedges may then be wedged in the slots 44 between the mold wall and side slabs 6. The inner engagement of projections 13 with grooves 38 prevent distortion of the circular opening in the assembled hot top. The grooves St? and 52 are provided in the side slabs because normal pouring procedure is to move the ladle in a direction passing over the side slabs. The rooves protect the wires against metal splashes. Similar grooves are not necessary on the end slabs because leaking metal does not normally fall on these pieces. The matching bevels 2t) and expand the bases of the slabs so as to tighten the bases against the mold wall. The design is such that the slabs will be tightened in a mold of the exact specified size of opening when the end slabs 4 are /2 inch higher than the side slabs 6. Normally molds are about 7 inch oversize, in which case the pieces will be level. As the metal is poured into the mold the exposed faces of the exothermic material near the top is ignited by the heat from the pouring stream while the exothermic material in the bottom of the slot will be ignited when the liquid metal level approaches it. The material burns at about the rate of 1 inch per minute from each end to produce a temperature of 3000 to 3500 P. which rapidly heats both the inside and outside sand walls. Since the sinkhead metal is not directly in contact with the exothermic material except for small portions thereof the metal will not be contaminated thereby. The inner side wall is made of such a thickness that it will cause to solidify a metal shell of sulficient thickness that the ingot may be lifted by its sinkhead. Once the shell has solidi fied the inner wall is extremely hot and the temperature gradient across it is very low so that heat flow outwardly from the sinkhead is elfectively restricted. The slabs are preferably made of sand with a resin binder which will volatilize so that the sand will disintegrate readily and fall off to provide a relatively clean ingot for rolling.

While one embodiment of my invention has been shown and described, it will be apparent that other adaptations and modifications may be made without departing from the scope of the following claims.

I claim:

1. A sectional hot top for a generally rectangular mold comprising a first pair of slabs one located on each of two opposite sides of the mold, a second pair of slabs one located on each of the other sides of the mold, each of said slabs being thinner at its center than at its ends, the inner periphery of each of said slabs being narrower than the outer periphery thereof so that the end faces diverge outwardly from the inner to outer faces, each of the end faces of the first pair of slabs tapering downwardly toward the opposite end face for the majority of its length and then at a greater taper to the bottom thereof, each of said end faces of the second pair of slabs tapering down- Wardly away from the opposite end face for the majority of its length and then at a greater taper to the bottom thereof, the first taper on the end face of the first slabs being at essentially the same angle as the first taper on the end face of the second slabs and the second taper on 4 the end face of the first slabs being essentially at the same angle as the second taper on the end face of the second slabs, and means for holding the top portions of the slabs together.

2, A sectional hot top for a generally rectangular mold comprising a first pair of slabs one located on each of two opposite sides of the mold, a second pair of slabs one located on each of the other sides of the mold, the inner faces of said slabs being arcuate in plan with the slabs being thinner at their center than at their ends, the inner periphery of each of said slabs being narrower than the outer periphery thereof so that the end faces diverge outwardly from the inner to outer faces, each of the end faces of one pair of slabs having a vertical triangular projection thereon and each of the end faces of the other pair of slabs having a vertical triangular groove therein for receiving the corresponding vertical triangular projection, each of the end faces of the first pair of slabs tapering downwardly toward the opposite end face for the majority of its length and then at a greater taper to the bottom thereof, each of said end faces of the second pair of slabs tapering downwardly away from the opposite end face for the majority of its length and then at a greater taper to the bottom thereof, the first taper on the end face of the first slabs being at essentially the same angle as the first taper on the end face of the second slabs and the second taper on the end face of the first slabs being essentially at the same angle as the first taper on the end face of the second slabs, and means surrounding the top portions of the slabs to hold them togethcr.

3. A sectional hot top for a generally rectangular mold comprising a first pair of slabs one located on each of two opposite sides of the mold, a second pair of slabs one located on each of the other sides of the mold, the inner faces of said slabs being arcuate in plan with the slabs being thinner at their center than at their ends, the inner periphery of each of said slabs being narrower than the outer periphery thereof so that the end faces diverge outwardly from the inner to outer faces, each of the end faces of the first pair of slabs tapering downwardly toward the opposite end face for the majority of its length and then at a greater taper to the bottom thereof, each of said end faces of the second pair of slabs tapering downwardly away from the opposite end face for the majority of its length and then at a greater taper to the bottom thereof, the first taper on the end face of the first slabs being at the same angle as the first taper on the end face of the second slabs and the second taper on the end face of the first slabs being at the same angle as the second taper on the end face of the second slabs with the second taper on the second slabs being longer than the second taper on the first slabs, and means surrounding the top portions of the slabs to hold them to gether.

4. A sectional hot top for a generally rectangular mold comprising a first pair of slabs one located on each of two opposite sides of the mold, a second pair of slabs one located on each of the other sides of the mold, the inner faces of said slabs being arcuate in plan with the slabs being thinner at their center than at their ends, the inner periphery of each of said slabs being narrower than the outer periphery thereof so that the end faces diverge outwardly from the inner to outer faces, each of the end faces of the first pair of slabs having a vertical triangular projection thereon, each of the end faces of the first pair of slabs tapering downwardly toward the opposite end face for the majority of its length and then at a greater taper to the bottom thereof, each of the end faces of the second pair of slabs having a vertical triangular groove therein for receiving the corresponding vertical triangular projection, each of said end faces of the second pair of slabs tapering downwardly away from the opposite end face for the majority of its length and then at a greater taper to the bottom thereof, the first taper on the end face of the first slabs being at the same angle as the first taper on the end face of the second slabs and the second taper on the end face of the first slabs being at the same angle as the first taper on the end face of the second slab with the second taper on the second slabs being longer than the second taper on the first slabs, and means surrounding the top portions of the slabs to hold them together.

5. A sectional hot top for a generally rectangular mold comprising a first pair of slabs one located on each of two opposite sides of the mold, a second pair of slabs one located on each of the other sides of the mold, the inner faces of said slabs being arcuate in plan with the slabs being thinner at their center than at their ends, each of the first pair of slabs including a generally vertical portion and a generally horizontal portion extending outwardly from the bottom of the generally vertical portion, the inner periphery of said generally vertical portion being narrower than the outer periphery of said generally vertical portion so that the end faces diverge outwardly from the inner to outer faces, each of said end faces tapering downwardly toward the opposite end face for the majority of its length and then at a greater taper to the bottom thereof, the inner periphery of each of the second pair of slabs being narrower than the outer pe riphery thereof so that the end faces diverge outwardly from the inner to outer faces, each of said end faces on the second pair of slabs tapering downwardly away from the opposite end face for the majority of its length and then at a greater taper to the bottom thereof, the first taper on the end face of the first slabs being at the same angle as the first taper on the end face of the second slabs and the second taper on the end face of the first slabs being at the same angle as the second taper on the end face of the second slabs, and means surrounding the top portions of the slabs to hold them together.

6. A sectional hot top for a generally rectangular mold comprising a first pair of slabs one located on each of two opposite sides of the mold, a second pair of slabs one located on each of the other sides of the mold, the inner faces of said slabs being arcuate in plan with the slabs being thinner at their center than at their ends,

each of the first pair of slabs including a generally vertical portion and a generally horizontal portion extending outwardly from the bottom of the generally vertical portion, the inner periphery of said generally vertical portion being narrower than the outer periphery thereof so that the end faces diverge outwardly from the inner to outer faces, each of said end faces having a vertical triangular projection thereon, each of said end faces tapering downwardly toward the opposite end face for the majority of its length and then at a greater taper to the bottom thereof, the inner periphery of each of the second pair of slabs being narrower than the outer periphery thereof so that the end faces diverge outwardly from the inner to outer faces, each of said end faces of the second pair of slabs having a vertical triangular groove therein for receiving the corresponding vertical triangular projection, each of said end faces of the second pair of slabs tapering downwardly away from the opposite end face for the majority of its length and then at a greater taper to the bottom thereof, the first taper on the end face of the first slabs being at the same angle as the first taper on the end face of the second slabs and the second taper on the end face of the first slabs being at the same angle as the second taper on the end face of the second slab with the second taper on the second slabs being longer than the second taper on the first slabs, and means surrounding the top portions of the slabs to hold them together.

References Cited in the file of this patent UNITED STATES PATENTS 2,159,374 Estep May 23, 1939 2,361,386 Eayrs Oct. 31, 1944 2,433,775 Marburg Dec. 30, 1947 2,433,803 Woodworth Dec. 30, 1947 2,572,452 Daley Oct. 23, 1951 2,782,478 Marburg Feb. 26, 1957 2,841,843 Nouveau July 8, 1958 2,900,685 Marburg Aug. 25, 1959 FOREIGN PATENTS 1,112,966 France Nov. 23, 1955