US1741615A - Hot top for ingot molds - Google Patents

Description

4 H.'L. COXEY 1,741,615

' HOT TOP FOR meow MOLDS Filed June 25, 1927 3 Sheets-Sheet l Dec. 31, 1929. H. COXEY 1,741,615

HOT TOP FOR INGO'I' MOLDS:

Filed June 25, 1927 v 5 Sheets-Sheet 2 mlllllll lilll l i atented cc, 31, 1929 ED STATES HORACE L. COXEY, OF MASSILLON, OHIO HOT TO]? FOR INGOT MOLDS Application filed June 25,

The invention relates to what are known in the art as hot to s, hot feeders, or sink headsfor ingot mol s.

The broad object of the invention is to prevent piping of the steel in the ingot mold, due to contraction in the steel caused by more rapidvcooling on the outside than on the inside. Other hot tops have been designed with this broad object in view, but in most inm stances they have not proved satisfactory on account of various factors, such as the expense of a complicated structure, the difiiculty of using certain types of hot tops where ordinary unskilled labor is employed; and the fact that with certain proposed types of hot tops unsound ingots are produced due to a slight porosity at the junction between the hot top and the ingot.

The present invention has been designed in view of the defects of previous hot tops, and the object of this invention is to produce a simple form of device, which may be manuv factured at relatively low cost, which is light in weight, requires no skill on the part of the 5 workman using the same, which will adequately prevent'piping, which insures a sound ingot at the junction between the ingot and hot top, and which permits a material saving of material, ordinarily wasted in the usual form of hot top. a

The invention is in some respects a combination of certain desirable features individually old in the art, into a single structure, for the purpose of eliminating the disadvantages possessed by the prior structures, and for producing a single device which will accomplish new and improved results. Certain other features of the invention are in themselves broadly novel, in additionto their cooperation with the other elements of the device to roduce the improved combination.

With these objects in view, the invention will be more fully understood by a brief reference to the conditions which are present in the pouring of steel into ingot molds.

When molten steel is poured into ingot molds, what is known in the art as a hot top feeder or sink head, isemployed for. feeding the molten metal caused by the shrinkageof the solidifying siderable pressure suchincrease in into the voids of the ingot,

1927. Serial No. 201,362.

steel in the mold. This hot top should be separate from the ingot mold, but should be light and cheap, and readily applied to the mold. The steel is poured until it fills the mold and the hot top. When the ingot has hardened it is removed from the mold, and that portion which was in the hot top becomes waste material, and is sheared off and discarded as scrap. It is important that the steel in the ingot be sound, and free from flaws or piping, and that it is free from porosity at the junction between the hot top and the mold. In order that the material in the ingot mold be sound it is necessary that conbe exerted upon it from above, and that the cooling be slow and uniform throughout. Increase in pressure may be had by increasing the height of the hot top, but with the ordinary form of hot top,

height would result in considerable additional loss of metal as scrap, and furthermore with high hot tops of ordinary construction there is an increased tendency toward uneven cooling with the resulting piping. Consequently it is necessary to strike a balance between the desirability of having as much pressure as possible and the disadvantages following from too high a hot top. The presentinvention permits of a high hot top, with less waste and less piping than in previous devices. L

In order to accomplish the desired results, the present device possesses certain characteristicfeatures which will now be described.

The hot top is made of a non-metallic porous insulating material with a smooth inner coating'of refractory material to prevent the metal from eating into the walls of the hot top. The insulating material of which the hot top is composed is highly porous, and is preferably made carbonaceous material with a refractory mass, molding in the desired form, and burning until a strong permanent bond is formed. The coil: or other carbonaceous material burn away in the kiln leaving still air spaces in the form of pores, which, with the insulating material of which the device as a whole is composed, forms a non-conductor of heat. In place of cork, finely divided charcoal, peat by mixing cork or other' and other carbonaceous material may be em ity, dead air chambers are molded within the llll walls of the insulating material. With this material no provision is necessary for sealing air or for releasing pressure as the pores in the material itself automatically take care of. that. A hot top so formed islighter than any previously known, on account of the material and construction, and thus allows easier I handling, which is an important factor, when it is considered that great numbers of them must be handled daily in the steel mills. No metallic casing is used,.and thus heat losses due to conduction are avoided and the weight of the metal is eliminated.

In order to produce the maximum pressure upon the ingot with the material in the hot top, the hot top is formed with abuse of substantially greater area than than the area at the upper portion thereof. The saving in metal due to this change in construction, by reason of the difference between the top and bottom areas amounts to from to for the smaller hot tops and more in the hot tops used for larger molds. This saving in metal is very considerable and the saving in metal over the ordinary mold is approximately equal to the. cost of the hot top, for one single casting operation. On

accountot this construction it is obvious that the height of the hot top could be increased without having to' pour more metal in the hot top for a given ingot moldthan is used in the ordinary type of hot top and such increase of height would, on account of the added.

pressure produce a sounder ingot than is pro ,duced according to the present practice, the

ordinary casting showing a slight porosity at the junction between the hot top andthe ingot, this porosity being evident when that portion of the ingot is etched with asuitable reagent. p

The combined device,iwith its larger base than top, and with its walls composed of light, porous insulating material, having a dead air space molded therein, will keep the 'metal hot and in liquid condition for along period of time, and thus the metalwill feed freely from the hot top. into the ingot mold as the metal in the ingot mold is shrinking down, and combined with the increased pressure due to the greater height of the hot top permissible when using this type of device, the construction and composition of the hot top as a whole insure a sound ingot in which piping and flaws are eliminated and in which there is a minimum loss in the form of scrap. I While it will be obvious that the invention is not limited to particular details of construcleast waste of scrap .the hot top.

Fig. 4- is a horizontal sectional view on line \i Fig. 5 is a vertical sectional view similar to Fig. 1, but showing a modification.

Fig. 6 is a horizontal section on line 6-6 of Fig. 5. v Fig. 7 is a bottom view.

Fig. 8 is a vertical section sh modification.

Fig. 9 is a horizontal sectional view on line 99 of Fig. 8.

Fig. 10 is a view similar to Fig. 9, but sh0wing a modification in which the hot top is circular in cross section as in Figs. 8 and;9.

Referring first to Figs. 1-4: inclusive, the reference numeral 10 denotes the usual metal ingot mold which in this instance is rectangularin cross section. Metal is poured into the ingot mold through a hot top 11 which is removable, and of light weight, and provided with handles 12 to facilitate lifting the same into position upon the mold. The hot top is of porous, insulating material, preferably produced by mixing cork or'other carbonaceous material with refractory material, molding the same into form, then burning out the carbonaceous material at the same time that the mass is hardened into permanent form. In this manner the walls are made porous, the pores being filled with still air, which provides excellent insulation. In order to increase its insulating capacity, and to further lighten the material the walls are provided with a plurality of large air spaces 13 within the walls themselves, and substantially surrounding the entire mass of hot steel within n this manner very light weight is secured, accompanied b highest efficiency from the point of view of insulation.

To form the air spaces 13, a hot, top form or mold is placed on a steel plate with the small end of the mold resting on the plate. This leaves the large end of the mold up, ready to be filled with suitable material and rammed. The first operation consists in ramming approximately one inch of material in the mold. Then strips or patterns of the proper size chambers are placed inside, and rammed to form the air spaces. The patterns are then withdrawn and the spaces left are covered with card board or heavy paper to maintain the air spaces. The remaining material for forming the hot top is supplied rather than square owing a third I and rammed. After the hot top is formed, it WhatI claim is is hardened by suitable heating, this heating A hot top for ingot molds having a wall operation serving to burn out the carbonacecomposed of insulating material having pores ous material within the mass, of which the hot therein communicating with the outer sur- 5 top is composed. face of the hot top and relatively large air 70 It has been found that the less material used spaces formed within said wall communicatin the hot top, and the thinner the wall's,where ing with the outer atmosphere through said made of suitable insulating materiaL'the less pores and sealed from the interior of the hot piping occurs. 9n the inside of the hot top, as top by means of smooth non-porous refractory 10 at 14, an inner layer of smooth, non-porous material. 75 refractory insulating material is preferably In testimony whereof I afiix my signature. employed. This serves two functions, name- I HORACE L. COXEY. ly, to preventthe steel frompermeating the pores of the hot top, and, second, to prevent the outside air from circulating into the in- 80 terior of the hot top, the lining thus cooperating with the dead air space 13 to produce more eflicient insulation. Such hot top may bevery thin and light indeed and is easily 7 2'0 handled.

As shown, the hot top is rectangular in cross section, and the area .across the base, as at 15,

' at the to of the ingot mold is much less than at 16, w 'ch is the limit to which steel is 25 poured, this being at the upper limit of the 0 siderable detail, for the purpose of illustra- 55 to help keep the metal liquid.

dead air spaces 13.

A suitable flange 17 extends into the ingot mold to prevent access of air at the junction between the hot box and ingot mold, and a 30 flanged seat 18 is formed at the base of the hot top, which rests upon the wall of the mold 10. This construction is simple and ch aply manufactured and is very efiiclent in preventing piping. A I 35 The construction shown in Figs. 5-7 is similar to that already described except that the hot top is in the form of a f rustum of cone, and I is adapted for use on a circular mold. It will also be noted that an outwardly extending 40 flange 19 is provided to serve as a seat for-the hot top upon the mold 10, and the dead air 7 spaces 13 are circularly arranged.

In Figs. 8, 9 and 10, the upper area of the hot top is substantially smaller than the lower 45 area, as in the previously described forms, but

' in this-case, instead of the walls flaring umformly outwardly from top to bottom, the walls are vertical fora substantial portion of their height, and flare abruptly outwardly 50 near the base as shown at 20 in Fig. 8. In

Figs. 8 and 9, the hot top is square in section, while Fig.10 it is circular. Otherwise, the

two constructions are the same.

The invention has been described in conno,

. tion, but it will be e 'dentthat it is capable of' many modifications within the scope of the appended claim.

The hot tops are in each case provided with 5 flat covers made of insulating material and. provided with'flanges projecting downwardly over the upper edge of the hot tops, these covers being designed to keep in the heat and

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