US3162913A - Hot top for the casting of molten metals - Google Patents

Description

G. R. WlTT HOT TOP FOR THE CASTING OF MOLTEN METALS Filed Jan. 29. 1962 Dec. 29, 1964 United States Patent 3,162,913 HOT TOP FOR THE CASTING OF -MOLTEN METALS George R. Witt, Avon Lake, Ohio, assignor to Foseco International Limited, Birmingham, England, a company of Great Britain Filed Jan. 29, 1962, Ser. No. 169,216 3 Claims. (Cl. 22-147) This invention relates to the casting of molten metals and more particularly to the construction of hot tops, head boxes, and heads of molds used for this purpose.

In the casting of molten metal in a mold to form an ingot or casting, a heat retaining lining, herein referred to as a hot top, is desirably provided at the head of the mold in order to conserve heat and keep an amount of metal molten so that it feeds the ingot or casting as it solidifies. Such a hot top often comprises a liningor insert within the mold, or in a head box attached to the mold, of sections of material having a special function. For example, the sections may consist of insulating refractory material, in which case they serve to delay transmission of heat away from the head metal and thus delay its solidification. Alternatively, the sections may consist of a composition of ingredients which interact exothermically when the composition is firedby the heat of the molten metal. In the latter case a more positive delay in the cooling of the head metal is achieved, which facilitates feed of the head metal to the body of the cast metal to compensate for the shrinkage of that metal as it cools. 1

To secure such sections in position asa hot top in a mold, various methods have been proposed such as the the use of wooden Wedges, or making the sections in a shape so that they are self-wedging. It will be appreciated, however, that since the sections are usually located in position by working above them, the wedges must be driven downwardly. When the molten metal rises in the mold and hot top, it exerts a substantial upward thrust on the lining or insert and as a result may dislodge the wedges and lift the hot top upwardly.

It is a primary object of the present invention to provide a new and improved form of hot top lining which is stronger, tighter fitting, and more reliable than hot top constructions heretobefore employed.

Another object of the present invention is to provide a hot top lining of the foregoing character which is formed of individual sections suitable for mounting in a mold or head box, and which, when mounted in place as a hot top is held tightly against the mold walls and successfully resists the upward thrust of the molten metal being poured.

Still another object of the present invention is to provide a hot top lining of the foregoing character which rigidly abuts against the mold walls to prevent leakage of molten metal between the lining and the walls.

Another object of the invention is to provide an improved hot top formed of sections such as relatively flat shipped in compact form and be readily and easily constructed into a hot top or mold lining in the place where it is to be used.

Still a further object of the present invention is to provide an improved hot top construction and mounting which eliminates the necessity of employing a stop-pour type of metal casting operation with the resultant sub- 3,162,913 Patented Dec. 29, 1964 ice stantial elimination of leaking or running stoppers, and thereby improves the yield of ingots and reduces the waste of hot tops. I

Other objects and advantages of the present invention will become apparent as the following description pro ceeds taken in connection with the accompanying drawings wherein:

FIGURE 1 is a plan view of a sectional hot top em bodying the present invention mounted in place in the mouth of an ingot mold.

FIG. 2 is a section view taken substantially in the plane of line 22 on FIG. 1.

FIG. 3 is a perspective view of a sectional hot top embodying the present invention in assembled condition just prior to mounting in an ingot mold.

FIG. 4 illustrates a compression clip used when mounting a hot top embodying the invention in an ingot mold.

While certain illustrative embodiments of the invention have been shown in the drawings and will he described below in considerable detail, it should be understood that there is no intention to limit the invention to the specific forms disclosed. On the contrary, the intention is to cover all modifications, alternative constructions, equivalents, and uses falling within the spirit and scope of the invention as expressed in the appended claims.

Hot top linings embodying the present invention find particular but not necessarily exclusive use with ingot molds. Such molds may be of any suitable type presently in use in the steel industry. These molds may be provided with a separate hot top casing (not shown) or the hot'top lining may be mounted directly on the mold or as an insert within the mold cavity.

One illustrative form of the invention is shown in FIGS. 1-3 and comprises a sectional sleeve shaped hot top lining or insert 10 mounted within the open mouth 11 of an ingot mold 12. It will be appreciated by those skilled in the art that the hot tops embodying the present invention are equally applicable to many other types of molds such as slab molds, and the invention is not restricted in its applicability to only molds of the type shown. In describing the invention, reference will be made to slab-like sections or slabs, although the invention should not be restricted.

In accordance with the present invention, there is provided a strong, self-supporting hot top formed of four slabs including two end slabs 14 and two side slabs 15 arranged to define a generally rectangular hot top sleeve. The individual slabs interlock one with another in a horizontal direction to form the rectangular sleeve and prior to mounting in a mold are held together by pins 16 extending through holes 17 in the interlocking portion of the slabs. In the interlocking hot top'shown forming this sleeve, the end and side slabs abut each other at the corners of the sleeve and each slab interlocks with the adjacent slab. Such an interlocking slab arrangement is described and claimed in copending application Serial No. 150,478, filed November 6, 1961, and assigned to the assignee of the present invention, now abandoned. The interlocking arrangement between the slabs is provided by a horizontally extending tongue 18 on one of the slabs which is received in a slot 19 defined by a pair of spaced horizontally extending tongues 20, 21 on an adjacent slab as shown in FIG. 3. These tongues are constructed and arranged so as to fit closely together to prevent leakage of molten metal between them when the sleeve is formed. To this end, the tongues may taper slightly from a larger vertical width at a point adjacent the slab body to a slightly smaller width at the free end of the tongue. These tongues extend horizontally from each vertical side of the slabs so that, by making the length of each tongue, as measured horizontally, equal to the thickness of the slabs when the slabs are interlocked at right angles, they form a rectangular sleeve- Ipipe 31 extending vertically through the slabs.

shaped hot top which is free from unwanted projecting surfaces or depressions, and at the same time a tight, rigid, leakproof joint is provided between the slabs.

For supporting the slabs'within the mouth of ingot mold, the two opposed side slabs 15 are provided in their upper edges, '-with upstanding rings or hooks 24 which are engaged by a bar 25 extending between the corre* sponding walls of the ingot mold, and which rest on the upper ends 26 of these walls. The bar 25'serv'es to support the hot top It? within the mold 12' and, because of the interlocking arrangement of the slabs 14, I5, the-sleeve 19' is securely supported with all of the slabs thereof in position adjacent the mold walls. 1

As shown in the drawings, the sleeve-shaped hot top lining 19 embodiying the invention is inserted within the open mouth of the mold 12 and when mounted in place is held tightly therein with the slabs forming the sides of the lining tightly in engagement with the walls of the mold. Alternatively, the sleeve-shaped lining could be inserted in a permanent hot top casing. The method of mounting to be described will be the same whether the lining is mounted directly in the mold or in the'hot top casing.

For holding the slabs which form the side walls of the hot top in tightlyjuxtaposed position againstthe mold walls, means are provided for expanding the sleeve to urge the slabs apart and into contactwith the mold walls. One illustrative means shown in the drawings comprises a generally Ll-shaped hair-pin like expansion clip 26, having a pair of downwardly extending and; outwardly inclined legs 27, 23-positioned at each corner of 'the As an alternative way of mounting the hot top sleeve in a mold, which avoids the use of the corner pins 16,

the expansion clip holes in the ends of the slabs may also be utilized to hold the slabs together and facilitate the insertion of the hot top sleeve into the mold. To this end, means are provided for engaging the holes and holding the slabs together. One illustrative means for this purpose comprises a 'compression clip 33 having a pair of legs 34, 35 which are biased inwardly toward each other and conneeted'at their upper ends by a spring loop 36 so that they can be pulled apart for insertion into adjacent holes' 30 in the-slabs forming a sleeve and when so engaged will tend to pull the slabs together.

Toiorrn a hot -top-usi1ig compression clips, the slabs 14, 15 are assembled and interlocked to form a sleeve; The slabs are lockedtogether by inserting a 'compres sion' clip into adjacent holes 3i? at each corner oithe sleeve, and the "top is-mounted in the open mouth of Other formsof hot top sleeves formed of a'plurality.

of slabs may be used in conneetio'n'withthe present invention, although they have not been illustrated. For

example, slabs which are tapered from top to bottom may be used to form a sleeve having a tapered interior,

, that is, an interior wall surface whichtapers downwardly hot top. For receiving the legs 27, 28 of such clips, 7

, each of the slabs is provided at a point adjacent each end thereof, with a ventical hole 30 definedby ametal These pipes are positioned at a point intermediate the wall surfaces of these slabs and adjacent each endthereof but at 'a point inwardly of the interlocking tongues 18, 20 and 21. The legs of the clip are slipped into the holes 30 of the slabs with one leg in the corner hole in one slab and the other leg in the corner hole in an adjacent interlocking slab. The hair pinexpansion clip 26 is formed from a bar of resilient steel so as to have suflicient spring strength to exert some force on the slabs and urge them apart. To accomplish this, the outwardly diverginglegs 27, 28 of the expansion clip 26 must be slightly comand outwardly; from a relatively narrower top open ing, to awider bottom opening. Also, the sleeves can be elongated for use in slab molds, or can even be sub stantially circular. In the'last mentioned case, for example, a circular sleeve might be formed in two semicircular, or semiannular, parts, or possibly three parts, for ease in shipment, and then assembled and inserted in a mold or hot top utilizing the expansion clips described above to hold the sleeve tightly against the mold walls.

With the expandable hot top construction described the danger of molten metal leaking between the hot top and mold walls is substantially eliminated because the hot top forming portions are held tightly against the mold '-walls. The hot top can'be shipped ma knocked down pressedor urged towards each other and then slipped into the holes. Itwill be appreciated, of course, that the legs mustdiverge to a greater extent than the spacing between the holes 3% in adjacent interlocking slabs.

To mount ahot top embodying the invention in a mold, four slabs are assembled in an interlocking arrangement as. described above, and are locked together by the insertion of the corner pins 16 through the interlocking 16 prevent the expansion clips 30 from expandingthe. 7

hot top slabs. The hot top sleeve (FIG. v3) is then inserted into the mouth of a mold 12 and is supported therein by bars 25- extending between the I hooks 24 on a pair of opposed side slabs 15.

condition and assembled at the foundry prior to use. The expansible nature thereof prevents damage to the top from misalinement' and further prevents the slabs from slipping once they aremounted in the molds. Moreover, the size of the slab is not critical as the hot top will expand into contact with the mold walls. If desired, the crack or opening leftbetween the slabs when theyexpand towards the mold walls can be quickly and V easily caulked or filled with ajsealing compound if so I The mounting operation is completed by withdrawing the corner pins 16 so that the expansion clips, 30 can urge the slabs into contact with the walls of the mold. 12. Because the clip tends to expand after being positioned in theholes, it will urge the slabs apart and" away from each other into contact with the mold walls. The frictional effects between the slabs and the mold walls will hold the slabsin this position during the casting of molten metal into the mold. This assures a tightifit between: the slabs and the mold walls, thereby preventing molten metal from leaking between the slabs and the mold Wall to forma fin on the ingot.

desired. V V

I claim as myinventron:

1. For use in an ingot mold, a hot topjcomprising,

four slabs arranged to form .a'sleeve, the abutting ends of adjoining pairslof said slabsincluding interlocking tongues, said slabs being provided'with longitudinal apertures extending downwardly. through substantially the entire length of said slabs adjacent each abutting end thereof, and sprin'g -tensioned' spreader means having a pair of outwardly biased legs fitted within the opposed apertures at the abutting ends of each adjoining pair oi said slabs for urgingsaid slabsapart, the legs of said spreader means extending downwardly through substantially the entire length of said slabs "so as to urge the lowermost portions ofsai d' slabs apart whereby when said hot top is inserted inthe mold at least thelowermost portions of. said slabs are forced tightlyagainst the mold walls.

2. For use in an ingot mold, a hot top comprising .four slabs arranged to form a sleeve, the abutting ends of adjoining pairs ofs'aidslabs including interlocking gitudinal apertures extending downwardly through substantially the entire length of said slabs and positioned at points intermediate the wall surfaces of the slabs and adjacent each end thereof at a point inwardly of the interlocking horizontal tongues, and spring-tensioned spreader means having a pair of outwardly biased legs fitted within the opposed apertures at the abutting ends of each adjoining pair of said slabs for urging said slabs apart, the legs of said spreader means extending downwardly through substantially the entire length of said slabs so as to urge the lowermost portions of said slabs apart whereby when said hot top is inserted in the mold the sleeve is expanded tightly against the mold walls.

3. For use in an ingot mold, a hot top comprising four slabs arranged to form a sleeve, the abutting ends of adjoining pairs of said slabs including tongues interlocking horizontally with the first one of said pair of slabs having a tongue extending therefrom in the plane of said slab and the second one of said pair of slabs having a pair of spaced tongues extending therefrom in the plane of said second slab and defining a slot for receiving the tongue on the first one of said pair of slabs, said slabs being provided with longitudinal apertures extending downwardly through substantially the entire length of said slabs adjacent each abutting end thereof, and a generally U-shaped spring-tensioned spreader having its outwardly biased legs fitted within the opposed apertures at the abutting ends of each adjoining pair or" said slabs for urging said slabs apart, the legs of said spreader extending downwardly through substantially the entire length of said slabs so as to urge the lowermost portions of said slabs apart whereby when said hot top is inserted in the mold the slabs are expanded tightly against the mold walls.

References Cited in the file of this patent UNITED STATES PATENTS 1,454,740 Howard et al May 8, 1923 1,892,464 Haws Dec. 27, 1932 2,301,101 Welshans Nov. 3, 1942 2,390,373 Jones et a1. Dec. 4, 1945 2,426,748 Rees et a1 Sept. 2, 1947 2,858,588 Hofiman Nov. 4, 1958 2,914,825 Marburg Dec. 1, 1959

Claims (1)

1. FOR USE IN AN INGOT MOLD, A HOT TOP COMPRISING FOUR SLABS ARRANGED TO FORM A SLEEVE, THE ABUTTING ENDS OF ADJOINING PAIRS OF SAID SLABS INCLUDING INTERLOCKING TONGUES, SAID SLABS BEING PROVIDED WITH LONGTITUDINAL APERTURES EXTENDING DOWNWARDLY THROUGH SUBSTANTIALLY THE ENTIRE LENGTH OF SAID SLABS ADJACENT EACH ABUTTING END THEREOF, AND SPRING-TENSIONED SPREADER MEANS HAVING A PAIR OF OUTWARDLY BIASED LEGS FITTED WITHIN THE OPPOSED APERTURES AT THE ABUTTING ENDS OF EACH ADJOINING PAIR OF SAID SLABS FOR URGING SAID SLABS APART, THE LEGS OF SAID SPREADER MEANS EXTENDING DOWNWARDLY THROUGH SUBSTANTIALLY THE ENTIRE LENGTH OF SAID SLABS SO AS TO URGE THE LOWERMOST PORTIONS OF SAID SLABS APART WHEREBY WHEN

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