US2283450A - Ingot mold - Google Patents

Description

Ma? 19, 1942 E. G. MITCHELL ET AL 2,283,450

. INGOT MOLD Filed DeC. 5, 1940 Y 5 Sheets-Sheet l E. G. MITCHELL ET AL INGOT MOLD Filed Dec. 5, 1940 3 Shee1'.s-Sh a-e'fl 2 INVENTORS ATTORN EY May 19, i942# E. G. MITCHELL ETAI. 2,283,450

, INGOT MOLD I@ K* I UNE I I 'l If/H III I I I I I I I I I I I I I I I I f/ly. W4

ATTORNEY Patented May 19, 1942 i ciro spares INGOT MOLD Edmund G. Mitchell, Godfrey Township, Madison County, and Harry C. Schaper and Edward Hartshorne, Alton, Ill., assigncrs to Western Cartridge Company, East Alton, Ill., a corporation of Delaware Application December 5, 1940, Serial No. 368,688 Y 4 Claims.

This invention relates to molds, and particularly to air-cooled molds suitable for casting metal ingots, for example, elongated slabs of nonferrous metal such as are adapted for rolling into sheets.

The various prior types of air-cooled molds in which a pair of mold sections were fastened together to form an ingot-casting chamber have not provided as good service as desired. In particular, the average working life of such molds has been undesirably short because of the distortion or breakage caused by the tremendous stresses arising from the expansion of the mold parts on heating and contraction of the same on cooling. t f

In the so-called hook-type lair-cooled mold;

which has been extensively used in the casting of slab ingots, the two mold sections are fastened in operative position by driving hooks attached to one section into place over pins on the other. In order to prevent the bulging of the mold sections between the fastening points, which otherwise would occur after use in a limited number of heats to such an extent that the mold could not be completely closed, it has Vbeen necessary to provide mold sections of rugged construction, for example, having heavy reinforcing ribs on the external surfaces of the working faces. This not only slows down the rate at which heat can be removed from the cast metal charge, but also gives rise to uneven temperature distribution and Atherefore additional stresses in the mold due to the abrupt changes in thickness. 'Ihe stresses occurring during the operation of such apparatus are necessarily localized, thus accelerating the breakdown of the metal structure, as shown by the fact that breaking of `the mold sections almost invariably takes place at one or more of the points of fastening. A further disadvantage of this type of mold assembly is that the uppermost hooks are necessarily fastened some distance from the top of the mold, and accordingly the upper ends of the mold sections tend to bend outward in use; the resulting ingots therefore have excess thickness of metal at the top end which in many cases must be removed before the subsequent operation of rolling intol sheets.

Modifications which have heretofore been proposed in order to overcome certain disadvantages have either not fullled the objectives in practice or have involved additional serious deficiencies.

Difficulties with the prior types of mold are 55 considerably magnified inthe casting of large ingots, such as the slabs, produced in accordance with modern practice, which are over six feet long, up to two feet wide, and up to several inches thick.Y y

An object of this. invention is to provide an air-cooled ingot-mold of simple construction having greater durability than prior molds.

A further object of this invention is the pro-v vision of a mold so constructed as to minimize localizedstresses during the production of cast, metal ingots.

Another object of this invention is` to provide an air-cooled ingot mold free of the disadvantages of prior molds. t f Y p Other objects will be apparent from the follow- A` ing detailed description.

In accordance with this invention, generally stated, the `Vforegoing objects are secured by providing a pair of substantially rigid frames for retaining complementary mold sections in position for receiving molten metal for the production of cast ingots, while distributing and absorb- Y ing the stresses incident to this operation. The sections of the mold are so constructed as'to avoid harmful stress gradients during operationV and, in the interlocked position, to provide support to the lateral walls, preventing the outward o opening of the same. The frames are of open structure, facilitating the rapid dissipationof the heat which must be removed from the mold before they can be handled.

`In the drawings forming part of this specification, there are'shown, by Way of illustration, a:

number of views of apparatus forming one embodiment in accordance with this invention, as follows: p

Figure 1 is a perspective View of the frames and mold sections assembled in position for receiving molten metal;

Figures 2 and 3 are respectively front and side views of the same;

Figures 4 and 5 are respectivelyfragmentary sectional Vviews taken along lines 4+4 and 5--5 of Figure 2;

Figure 6 is a longitudinal section along line 6-6 of Figure 2 Figures 7 and 8 are respectively front andside views of a mold section; and

Figure 9 is a side view of tion. g l

In the improved air-cooledingot-mold of this the other mold sec- Y invention, a support for mold sections is provided consisting of a front frame kl and aback frame 2. Each of these frames is preferably of Voneingot and piece construction, formed of cast steel of sub- 'stantial thickness, and consists of a pair of Vertical end-posts connected by means of a plurality of bars into a rigid open structure. Hinge members 3, integrally formed with they frames, are provided at the base and are adapted for being iitted together and forming a hinged joint between the frames on insertion of the pin 4.

For fastening the two frames together, a plurality of lugs are provided, integrally formed with and extending laterally from the end-posts in cooperating positions. When the fastening means consist of the preferred vbolt and. socket assemblies shown, the front frame is provided with transversely-slotted lugs 5, each of which. is op.-

posite a pair of lugs 6, having a longitudinal bore adapted to house pin 1, on the back frame. Threaded sockets 8, pivotally connected with lugs 6 by means of trunnions 1, are adapted ltobef sectionV I2 is provided with longitudinal; end walls.

I3, bevelled at the external edges, which are l adapted to form a tight fit within a pair of lon- A gitudinal grooves I4 bordering the working face of front section II. The longitudinal ed'ge portions, of front lII, beyond the grooves,V le, are somewhat thickened in order to support endwalls I3 and prevent the outward opening thereof, which would occur in the. absence of such provision after repeated casting, Operations. Lugs I6 are provided onv the moldv sections for fastening the same to the' respective frames, by meansY of clamps IIV bolted thereto. Front I`I is provided withv a horizontally extending base por-- tion I5, adapted for insertion to formla tight. t betweenV end walls I`3" of back I2.

slightly thicker at the center than at the edges.

It has been found that the durability of the mold sections is considerably enhanced' when.

their external'surfacesopposite the working` facesy are smooth, that is; free ofprojecting parts.- such as reinforcing, ribs. Accordingly, harmful stress gradients during the casting` processare avoided.

by providing mold sections which either are of substantially uniform. thickness at' the workingface or gradually increase in thickness from the.

longitudinal edges tofthe center of. the working face. Y

Adequate distribution of the stresses arising during operationis insured by the provisionof a plurality of'fastening devices evenly spaced along.

the frame end-posts, one set being. placed. nearv the top and another' near the bottom:Y ofY theA mold sections. Excellent results have-.beenobf tained in casting slab ingots about six. feet long by the useof' five pairs of bolt and socketassemblies evenly spaced along the frames, and, of Isix such sets of fastening meansv for ingotsV about eight feet long.

In operative position, contact is provided between the frames and the mold sections, for the support ofthe latter, at-a number of projections I8, Aintegrally forme'don. the frame and 'preferably-- symmetrically disposed` withV respect' to; thev jas-- sembly fastening. means.A Accordingly,L unob- Both working faces taper inward',A providing a mold charnr'zer1 structed lateral openings are provided between the frame and the mold sections, in addition to the relatively extensive front and back openings of the frames, for the free circulation of cooling airat the external surfaces ofthe mold sections.

In operation, a number of the above-described ingot-mold assemblies are mounted ralong a channel I9, adapted to receive base 2D, forming a unitary extension of back frame 2. Back frame 2 is preferably fastened in slidable engagement with rack-ba`r 2I by means of clamps 22. To facilitate. the pouring of molten metal, a funnel 23r of usual construction may be attached at the top` of. theV assembled mold in any,suitable manner, for example; by means of pin 24 inserted through pierced tabs 25 on back section I2.

On receiving a charge of molten metal, the mold sections undergo a large rise in temperaturezan'd therefore an appreciable expansion. In

the present improved assembly, however, this ex-V pansionoccurs to a considerablewextent in the. vertical direction, thus largely avoiding deteriorating, effects on. theY parts; since sections I'I" and* i2 are free' to move'longitudinall'y both with respect .to one anotherand tothe frames.

Afterthe metalicharge has solidified' and cooled to a: convenient handling temperature, Vbolts 9Y are loosened' and swung' out' of engagement with',

the slots of' lugsA 5', the front frameA I', to which section I'I,A is fastened', is' swung forward' to open the mold, and' the sl'ab ingot may' then be removed; The mold assembly may,l thereupon beA closed toreceive another' charge4 of molten xrretal.V Replacement of"either the front section II orv back section I2 may be simply and rapidly effected whenever desired merely by looseningl clamps I'I", substituting thei newV for the used'section, and tightening'clamps I'I over lugs I6.

Asv an addedA feature of"exbi1ity,lframes o'f' any' given size may be utilized* to enclose arvari'ety of sizes of mold sections, capable of producing4 s labingotsl differing as; muchas several inches in width". Accordingly, aA much'smaller number of framesis required' than` wouldv otherwise bel the'Y I case; l Y

As 'indicated inthe' drawings; the frames are substantiallyv thicker. than. the mold sections. For example,` in a; preferred ernbodirnent, the

. frarne end-posts and connecting bars consist. ofl

cast steel onev and three-quarter 'inches thick whilethe: thickness dimensions of the mold sections formed of cast semi-steel or similar'metal alloy', are" respectively. for the mold front,..one inch at the' working4 face and' one anda quarter inches' at the edges' beyond' the grooves,.and for the moldback, oneand aquarter inches at. the center anlthree-quarters of'an incht at'. the. edges of'theworkingface.

The novel; type of air-cooled' in'got. moldv aslsembly disclosed herein permits the use. ofmoll sections" whichV are considerably lighter thanv those heretofore employed For example,.mol`d sections of the present'type, may have aweight amounting to about or lessfof the weight of theK prior hook type mold sections producing ingotsoffthe same size The excess weight' of the prior hookf' type mold is'due'partly'to'the' heavy Vexternalribs provided, as has beenj customary in the' art,.i`ork re"- inforcing both thefront and'back moldsections. Such ribs cause avariation in thickness at vthe working'faces ofthe moldsections; for example, in the case ofa`moldl producing ingots of rec-- tangular cross-section 1124/2y inches long; and? 1%' 75 incheswide, from` two-and: one-eighth inches'at the ribs to one inch between the ribs, which variation is sufcient to create harmful stress gradients 'during casting operations.

While in the above-described embodiment, the frames have been described as formed of cast steel, it is to be understood that other suitable metal alloys or dierent methods of fabrication may be useful; for example, the frames may consist of Vwelded structures. The bars connecting and reinforcing the frame end-posts may be of any suitable type providing a rigid frame and not obstructing the circulation of air at the eX- ternal surfaces of the mold sections. Although the described bolt and socket assemblies are preferred for securing the frames together, other suitable types of fastening means may at times be employed.

The outstanding advantage of the ingot mold assembly in accordance with this invention is the considerable increase in durability which it provides. Thus, in extended tests of molds, producing copper alloy slab ingots, in which the present apparatus was compared with the prior hook type, the mold sections in each case consisting of castings .of the same semi-steel alloy, the average life of the mold members in accordance with this invention was from two and a half to three and a half times that for the prior molds. It is furthermore noteworthy that the ingots produced with the present mold are of substantially uniform thickness throughout their length. The durability of the frame members is of such high order that no signs of deterioration are present even after extended use, and the frames can accordingly be expected to outlast many sets of the mold inserts.

It will accordingly be seen that the objects of this invention are accomplished in the provision of an air-cooled ingot mold assembly having outstanding durability, convenience and ease of operation, and which is capable of producing slab ingots of excellent quality. The foregoing description is to be considered as illustrative rather than restrictive as various changes in structure or materials are contemplated within the spirit of the present invention and without departing from the scope of the appended claims.

Having now described the invention, what is claimed as new and is desired to be covered by Letters Patent, is:

l. An air-cooled ingot mold comprising a pair of substantially rigid hingedly-joined frames each consisting of an open one-piece structure lof elongated end-posts connected near the ends andV longitudinal contact therewith solely at the said projections, said mold sections being adapted to interlock forming a chamber open at one end, and means forcing the said frames toward one another to interlock the said mold sections.

2. An air-cooled ingot mold comprising the combination of a pair of substantially rigid frames each consisting of an open structure of end-posts connected near the ends and at intermediate points by bars; a mold section, having a substantially smooth external surface, clamped in each of said frames, one of said sections having side walls adapted to be vreceived by longitudinal grooves in the rsecond section and said second section being thickened at the edges be-` yond the said grooves and being provided with a base fitting closely between the said side walls; and means forcing the said frames toward one another to interlock the said mold sections.

3. An air-cooled ingot mold comprising the combination with a pair of interlocking mold sections ofa pair of substantially rigid frames,V

each consisting of an open structure .of end-posts connected near the ends and at intermediate points by bars; a plurality of'means on the endposts for forcing the frames toward one another; and a plurality of projections, symmetrically disposed on the said end-posts withrespect tothe said forcing means, contacting the said sections for holding the same in interlocked position.

4. An air-cooled .ingot mold comprising a pair 'of substantially rigid hingedly-joined frames,

each consisting of an open structure of endposts connected near the ends and at intermediate points by bars; a pair of smooth-sur-Vv faced interlocking mold sections, adapted to form an elongated chamber openA at one end, in said frames; a plurality of spaced projections on the saidframe end-posts contacting the said mold sections near their longitudinal edges; and means forcing the said frames toward one vanother to interlock the said mold sections. Y

EDMUND G. MITCHELL.

HARRY C. SCI-IAPER. EDWARD HARTSI-IORNE.

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