US2093024A

US2093024A - Ingot mold stool

Info

Publication number: US2093024A
Application number: US710985A
Authority: US
Inventors: Edward R Williams
Original assignee: Individual
Current assignee: Individual
Priority date: 1934-02-13
Filing date: 1934-02-13
Publication date: 1937-09-14
Anticipated expiration: 1954-09-14

Description

. Sept. 14-, 1937. E. R. WILLIAMS 2,093,024

INGOT MOLD STOOL Filed Feb. 13. 1934 INVENTOR Patented Sept. 14, 1937 uNnEoisTArEs PATENTOFFlCfi 7 ,INGOT Motn's'rooL This nvention relatesj to 'ingotlmoldsfand .more particularly to improvements in ingot mold stools forsupport. of molds of the, open-end type which are adapted to be positioned-on thestool with the big end of the ingot up when in casting Dosition',=and to a method of,casting.,ing"ots in such molds.

In casting ingots in anopen-bottom mold of either thebig end up or thebig end. down.type, the mold is Jpositionedon a, suitable stool usually made of cast iron, which supports the bottom end-of the ingot ;Whe n amoid of the so-called plug bottom type isused, thebottom end thereof isqgenerally closed-witha suitable metallic plug, which is slightly smaller than-the internal diameter of the-mold.

When theingot is being .cast, the-molten metal which is poured into-the top of the mold falls against thetop of ;the;;plug orstool, and as it comes in contact therewith; it welds to the plug or stool and also;-;i;requently splashes, and impinges against the isides of the mold. -As,a result of the moltenmetal welding to the plug-or stool and to thesides of the mold adjacent the plug or stool, the difilcultiesencountered in stripping the ingot from the mold are materially increased since there is always present the danger of cutting-the mold wall adjacent the plug or stool during the stripping operation or pieces of the mold-wall may be broken away which results in the premature scrapping of the mold. Hence, the-weldingof the ingotto the plug or stool and to the mold wall, not only increasesthe expenseandtime 01 stripping the ingot from the mold, but also cracks are formed in theingot which necessitatesthe'discard of .a large portion ofthe bottom end ofthe ingot:

I am aware that attempts have been madeheretofore to-overcome these difliculties, that is, to prevent the ingot 'from welding to the plug closing the' bottom of the mold to prevent the metal'fromsplashing onto and welding to the sides of the mold adjacent to the plug. For example, in the patent to Howard & Turner, No. 1,335,865, a. refractory insert for a mold stool is disclosed for eliminating these objectionable features. This insert is made of refractory material to prevent welding, is dished out to prevent splashing, and it is stated to be for the further purpose of retaining heat in the bottom of the molten metal to prevent rapid cooling thereof and thereby secure an even cooling of the entire ingot and as a result, reduce ingot cracking and the formation of pipes therein.

While this patent contemplates a, mold stool ingot and as a result,

These and other objects which will hereinafter i gi w -P r ti h b i l area, and etainthe heat'inthe'ingoflit will otjeliminatetpr concentliateltheformation, or, shrinkage cavities pr piping in the to 'dfthjh gcit which can only be done ,by solidifying.themetal'hdjae 5 cent the bottom ,of th? mold'wlilileithemetal'at x the topof the oidgissti mone sdthatf'it hbws into and fills. up .the pipin'g. V

It is the, principal object of "the present "inventlon er or/idea nsff c os nsi'th bottom end,of a mold which .will extract andjoa'luse; the heat in the molten. metal to be dis'sipated instead of retained,and thus cause the lower end oi the ingot to be solidified much more rapidly than, is the upper end and'as afresult, cause a concentration of gthe shrinkage cavity or piping l in the top oif the ingot. I Another.,object of this, invention is to provide a seal forthe' lower end of a, mold which will prevent the metal being poured from welding to the mold stool. I h

A further-object oi this invention is to provide a method of casting ingots in which thev speed of solidification of the metal adjacent the lower end of the mold takestplacemuch more rapidly than the solidification of the upper-end of the shrinkage cavities are confined to the top ofthe mold and the amount of the ingot which must be discarded, due to suchrcavitieais' materially reduced.

be made apparent tothose skilled inuthis 'particularart, I attain by means of this" invention, one embodiment of which described in thejfollowing specification and illustrated in theaccompanying drawing, wherein:

,Figure 1 isa view partiaJly'finfvertical section and partially vin elevation of anQopen-end'mold, bigendiuptype, which is supported on a: stool embodying-my invention; 40

Fig. 2 is a view in perspective. of a moldfstool;

Fig. 3 is a view in perspective of the insert for the mold stool.

Referring to the drawing, l0 represents a body of a mold of the open-end type having a molding wall II which tapers from one end to the other and is adapted to have its big end up when in casting position. The outer face of the mold I0 is provided with staples I! for receiving the hooks (not shown) of a hoisting device for lifting the mold.

When in position for casting, the mold rests upon a stool l3 which-is made 01' cast iron or other suitable material, and is provided at its outer edges with upstanding lugs I which are cut away on the inner races thereof to form bevsuitable metal having a high thermal conductivity is snugly positioned. Preferably, the area of the recess at the top of the stool i3 is considerably greater than the inside area of the mold, but of smaller area.than the outside area thereof so that when the mold i0 is positioned on the stool II, it rests entirely on the member H, the top of which extends slightly above the top face of the stool. The upper face of, member I! is provided with a dished-out portion ii to prevent the molten metal falling thereon from splashing and welding to the wall ll of the mold. Since the top of the member ll extends slightly above the top of the stool II, it is apparent that the mold i0 is supported directly on the member I! and a tight joint is formed between the mold and the member which will prevent the molten metal from flnning or leaking out therebetween and thus make it dililcult to strip the ingot from the mold.

In casting, the mold 10 is positioned on the copper member I! which is supported by the stool II and molten metal is poured into and fills the mold it. The molten metal, as it drops in the mold, strikes in the dished portion ii of the copper member ii the mass of which is preferably less than one-third the mass of the ingot being cast thereon. As the mold is filled, the heat in the molten metal adjacent the bottom of the mold is extracted by the copper member I! and I have found that when the weight of the copper is approximately one-third the weight of the ingot being cast that it has sufficient mass and heat capacity to absorb the heat from the ingot without having its temperature raised to its melting point or to its welding point. Since the heat in the ingot adjacent the member I! is rapidly extracted and absorbed by the copper member II, the bottom of the ingot is quickly solidified while the metal in the top of the mold is still in its molten state and as a result there is a concentration of piping in the top of the ingot. The dished-out portion [8 of the member i1 is of sufiicient depth and shape to prevent the molten metal from splashing and impinging against the walls of the mold severely enough to weld thereto or to cut the wall of the mold.

From the foregoing description it is apparent that the lower end of the ingot rests on the copper member i1, and since this member has a high thermal conductivity. the heat in the lower end of the molten metal is quickly dissipated and as a result, not only is the metal prevented from welding to the member H, but also the lower end of the ingot is quickly solidified and piping which would ordinarily be formed therein is filled with a,o9s,o24

the still molten metal in the top of the mold and the shrinkage cavity or pipe is concentrated in the top of the mold which is the last part of the ingot to solidify. The heat in the metal in the top of the mold may be retained to prevent solidification thereof by use of an ordinary reiractory hot top which is adapted to be positioned on the top of the mold.

While I have described my preferred construction as having the member ll of such height that it extends a slight distance above the top of the stool i3 and of an area larger than the internal diameter, it is to be understood that the top of the member i'l may be made so that it is flush with the top of the stool and it may be of the same or slightly less area than the end of the mold supported on the stool. Such construction may be especially desirable with the "big end down" type of mold since it would permit molds of various sizes to be used on the same stool and further, it would permit the weight and size of the member needed in connection with my preferred construction to be reduced for the bigger molds.

Further, it is apparent that the entire stool may be made of a material having a high heat conductivity as well as having a cast iron stool with an insert made of such material as de-' scribed. It is also apparent that other changes,

additions, substitutions and omissions may bemade therein without departing from my invention and the scope of the appended claims.

What I claim as new and desire to secureby Letters Patent is:

1. An ingot mold and base assembly comprising a base member having a pocket therein, a mold, integral means on the base member for centering the mold on the base member and restraining them from relative lateral movement, and a replaceable copper insert in the pocket, the top of which projects above the top of the pocket and on which the mold rests whereby the weight of the mold is transmitted through the insert to the base assuring a tight seal between the mold and the insert.

2. An ingot mold and base assembly comprising a cast iron ingot mold, a cast iron base member, a copper insert in the base member, means on the base member for centering the ingot mold with respect to the copper insert and centering the copper insert with respect to the mold, the copper basemember having a bearing surface-"to engage the bottom of the mold and a thickness such that the weight of the mold is transmitted through the insert to the base, whereby a tight seal is formed between the insert and the mold while the base serves to align and center the parts EDWARD a. WILIJZAMS.