US2339601A

US2339601A - Ingot mold

Info

Publication number: US2339601A
Application number: US416877A
Authority: US
Inventors: Gathmann Emil
Original assignee: GATHMANN RES Inc
Current assignee: GATHMANN RES Inc; GATHMANN RESEARCH Inc
Priority date: 1941-10-28
Filing date: 1941-10-28
Publication date: 1944-01-18
Anticipated expiration: 1961-01-18

Description

Jan. 18, 1944. E, GATHMANN 2,339,601

INGoT MOLD Y Film oct; 28,Y v1941 gmc/YM Patented Emu Gath'mann,

Gathmann Research Baltimore, Md.,` assignor to Incorporated, Catonsville, Md., a corporation of Maryland Application october 2s, 1941, serial-N0. 416,871

s claims. (ci. ,2a-139) This invention relates. to ingot molds, and more particularly to metallic ingot molds having big-end-up ingot-forming chambers. this general class have been known in the art for many years and now are used extensively, particularly in the production of high quality steels. Many factors enter into the production of sound ingots in molds of this class, and, aside from the Apreparation of the metal itself before it is teemed into the molds, which of course is important in the making of any metal product, such factors are generally the cross sectional contour of the mold chamber, its vertical contour, and the relation of mold wall thickness to the chamber cross section at different zones vertically of the mold.

Generally stated, it is fundamental, in view of prior art disclosures, for the thickness or heatabsorptive capacity of big-end-up mold walls to be so related to the mold chamber cross section that ingot metal will cool and solidify progressively from bottom to top. Such a mold is shown, lfor example, in my early- Patent'Number 974,133,

granted November 1, 1910, and in many other patents to myself and to other inventors. The cross sectional area of a big-end-'up moldchamber being larger at the top than the bottom, the

inner surfaces of the mold walls naturally have an'upward-outward slant which, in itself, tends to make the walls of diminishing thickness and lessening heat-absorptive capacity progressively from bottom to top. In most prior art molds, this progressive diminishing of the heat-absorptive capacity has been augmented by slanting the wall outer surfaces upwardly-inwardly. In a few instances it has been proposed to provide an upward-outward slant for wall outer surfaces, relying upon the progressive increasing of the chamber cross section from bottom to top to bring about the desired cooling and solldiflcation of the ingot progressively from bottom to top.

In my prior Patent Number 2,166,587, granted July 18, 1939, there is disclosed and claimed a .big-endhup mold the inner or matrix wall surfaces of which are differentially slanted upwardlys-outwardly from bottom to top; that is, the matrix surfaces have different degrees of slant indifferent vertical zones, there being a higher -degree of slant in the lowermost side Wall inner surfaces than in the above and adjoining side wall inner surfaces. The outer surfaces of the moldwalls shown in Patent 2,166,587 are slanted upwardly and inwardly according to the prevailing practice at the time of the invention disclosed in the patent. The differential slanting of the mold wall inner surfaces has been found to pro- MOldS 0f mote soundness and reduced lsegregation of the ingot metal, to reduce ingot surface defects, to

reduce crop loss, to facilitate initial reduction of the ingot in the rolls, and to prolong mold life.

invention is to prohaving differentially An object of the present vide a big-end-up mold slanting side wall inner surfaces of the general character rections of extent of are so related to the slantlng in different vertical zones as to still further. promote the obtaining of the desirable physical charreferred to above and in which thedithe mold wall outer surfaces acteristics of an ingot produced in the mold.

Another object is to provide a mold of the general character referred to in which the directions of extent of the wall outer surfaces, and the mold wall thickness in different zones, are

' so related to the chamber cross sectional area as to promote the production of sounder ingots. with the use of a lower ratio of mold metal weight to ingot metal weight than it heretofore has been' possible to use in the production of sound ingots.

In accordance with the invention, a big-end-upA mold having differentially slanting wall inner surfaces has outer wall surfaces which preferably are free from the upward-inward slant heretofore characteristic of such molds. The wall outer surfaces may slant upwardly and outwardly, but to a lesser degree than the lowermost portions of the wall inner surfaces.

In a preferred form, the upward-outward slant of the wall outer surfaces is substantially the same as the upward-outward slant of the wall inner surfaces above the lowermost inner surfaces.

' Thus, throughout a substantial part of the mold above its lowermost wall surfaces, the walls may be of substantially uniform thickness; as distinguished from the lowermost walls of progressively diminishing thickness. Further, itis preferred, in accordance with the invention, that the ratio of the cross sectional area of the mold chamber to the cross sectional area of the mold walls at the bottom of the mold bear a certain relation, within a generally limited range, to the ratio of the cross sectional area of the mold chamber to the cross sectional area of the mold walls at the top of the mold; The relations be` tween the slants of mold wall surfaces, and ratios of chamber cross lsectional area to mold wall cross sectional area may vary in accordance withl the size of the molds. VA mold embodying the invention in one form is shown in the accompanying drawing, in which:

Figure 1 is a vertical sectional view; and

Figure 2 is a top plan view.

inner wall surfaces 2 i j o The invention may be embodied in big-end-up molds having differentially slanted side wall inner surfaces and cross sectional contours of various kinds. For the purposes of illustration, there is disclosed a cast iron mold M having a cross sectional chamber contour of the kind disclosed and claimed in my Patent 2,240,396, granted April 29, 1941. However, vertical mold wall contours formed in vaccordance with the present invention may be embodied in molds not necessarily of generally rectangular cross sectional contour. In

the present specication, the plural term walls" r main or body portions are substantially straightand slant upwardly and outwardly from the longitudinal axis of the mold chamber; but the surfaces 3* slant to a greater degree than the surfaces 4i. The relative amounts of slant andthe relative height of the more greatly slantedsurface 3 may vary in dependenceupon the horizontal cross section of the mold chamber, but the lower slanted surface 3a preferably should be between about twenty per cent and fty per cent of the total length of the mold chamber, and

it should be slanted preferably two to twenty times as much per inch of height as the adjoining upper inner surface 4a. It usually is advantageous to employ an extreme upper wall portion 5 having an inner surface 5u which is substantially vertically or parallel to the vertical axis of the mold chamber.

Depending upon the size and` assaeoi progressively reduced rate of cooling of the ingot metal-brought about by the absorption of heat by the wall portion 4 is due to increase of the mold chamber (and ingot) cross-sectional area v progressively from botto'n to top, rather than to decreasing mold wall thickness. However, in order to avoid various kinds of iiaws and unsoundness in the lowermost portion of an ingot, the inverse cooling gradient from bottom to top of the wall portions 3 should be rather steep, and

in molds constructed in' accordance with the present invention the desired relatively rapid decrease in the A cooling capacity from bottom to top of Vthe wall portions 3 is assured by forming the inner surfaces of the wall portions 3 with a marked upward-outward slant, even though the associated outer 4wall surfaces are formed without upward-inward slant.

Molds constructed as described herein have been used in the production of large tonnages of ingots of sounder structure than heretofore has been generally obtainable. Aside from the vcapability of producing improved ingots per se,

. molds embodying the invention have an addicross section of the mold chamber, the section 5 may be of varying length which should be somewhat less than the maximum cross-sectional dimension of 'the mold chamber and preferably should be between about ve percent and twenty per cent of the mold chamber height. The bottom 2 is of necked-in concavo-convex contour, preferably of the kind disclosed and claimed in my Patent 2,242,703, granted May 20, 1941.

In accordance with the present invention, the outer surfacesof the mold

side wall portions

3, 4, and 5 preferably are free from upward-inward slant. In the form shown, the outer surfaces 6 are straight and have a slight upward-outward slant. Ihe relation of the outer surfaces 6 to the inner surfaces 3, 4a, 5a of the wall portions 3, 5. and 5 is such that the thickness of the lowermost side wall portions 3 progressively diminishes to a marked degree from bottom to top, whereas the

wall portions

4 and 5 lare of substantially uniform thickness throughout their vertical extents, although a slight progressive diminishing f tremendous savings possible. perishable, a life of eighty heats usually being ore, less scrap re-melting, and less space and in thickness from bottom to top of these wall portions will not actually be harmful. Major dimensions of the mold shown generally to scale in the accompanying drawing are marked on Figure 1, it being understood that, although the mold shown is a commercial embodiment of the invention, the dimensions are not intended to `be used by way of limitation. The outer surfaces Si of the walls slant upwardly-outwardly only a very little less per inch of height than the inner surfaces 4 of the wall portions 4, and the thickness of the

wall portions

4 and 5 therefore is substantiallyv uniform throughout. Thus. the

tional f and very important advantage in that, for forming and properly cooling an ingot of a given weight and shape, they can be made of less mold metal than heretofore was possible. Extensive commercial use of molds embodying the present invention has shown that, for a given size ingot, and with other factors being'generaliy the same, molds having inner and outer side surface contours related as disclosed herein and weighing twenty percent less than prior art molds having similar inner contours are capable of producing ingots which are fully as sound as or sounder than ingotscast in the heavier molds of the kind heretofore known in the art. Commercial use also has demonstrated that the lightening of the molds in accordance with the present invention does not shorten the mold-life appreciably.

It will be apparent that the lightening of molds in accordance with the present invention makes Ingot molds are considered good. After molds have become pitted, cracked, eroded, or otherwise rendered unfit for further service, they must be scrapped and re-melted.Consequently, lightening of the mold not only results in a direct saving in the cost of equipment used in the production of ingots, but also effects a multitude of substantial indirect savings such as less transportation of weight carrying capacity in transporting the molds from the foundries to the steel plants.

It is necessary that the molds be heavy enough, particularly at the bottom, to effect proper chilling and solidication of the ingot metal. In the mold shown inthe drawing, the ratio of the -mold cross-sectional arear to the chamber cross-sectional area is about 1.68 at the level C at the bottom of the wall portions 3, and is about 1.03 at the level A at the top of the wall portions 4 and 'thereabova For producing sound ingots in light and therefore economical molds having differentially slanted side wall inner lsurfaces and side wall outer surfaces free from upward-inward slant, the ratio of mold wall cross-sectional area assacoi stood that changes may be made without departing from the invention as defined in the claims.

I claim: 1. A metallic ingot mold comprising bottom and side walls having outer surfaces and inner tions, comprising from twenty per cent tov fifty per cent of the total side wall -inner surface length, being slanted upwardly and outwardly to a materially greater degree than the adjoining intermediate opposed side wall inner surface sections, and said intermediate opposed side wall inner sections being slanted upwardly and outwardly more than the opposed extreme upper side wall surface sections, the outer surfaces of said opposed side walls. from bottom to -top being lfree from upward-inward slant, the ratio of the mold wall cross-sectional area to the chamber cross-sectional area being approximately 1 to 1 at the top oi' the mold and being approximately 1.7 to 1 at the bottom of the mold, the ratio of the mold wall cross-sectional area to the chamber cross-sectional area at the bottom of said lowermost sections thus being greater than but not more than twice as great as the ratio of the mold wall cross-sectional area to the chamber cross-sectional area adjacent the top of the mold. i

2. A metallic ingot mold comprising bottom and side walls having outer surfaces and inner surfaces, the latter defining a big-end-up ingot forming chamber, the mold walls progressively decreasing in thickness from the bottom upwardly adjacent opposed lower inner tide surface portions and being of substantially uniform thickness adjacent opposed inner side surface portions aboveand adjoining said lower opposed inner side surface portions, the ratio of the mold wall cross-sectional area to the chamber crosssectional area being approximately l to 1 at the top of the mold and being approximately 1.7 to 1 at the bottom of the mold, the ratio of the mold wall cross-sectional area to the chamber cross-sectional area at the bottom of said lowermost sections thus being greater than but not more than twice as great as the ratio of the mold wall cross-sectional area to the chamber cross-sectional area adjacent the top ofthe outer and inner surfaces of which both define a big-end-up contour, the ratio of the crosssectional area of the walls to the cross-sectional area of the chamber in the upper part of the mold being approximately 1 to 1 and increasing towards the bottom of the mold, the ratio of the mold wall cross-sectional area to the chamber cross-sectional area at the bottom of the mold being vgreater than but not more than twice asgreat as the ratio of the mold wall` cross-sectional area to the chamber cross-sectional area adjacent the top ofthe mold.

4. A necked-in bottom metallic ingot mold, the outer and linner surfaces of which both define a big-end-up contour, the outer surfaces having a single yslant from top to bottom and the inner surfaces having at least two degrees of slant, the greatest degree being in the lower portion of the chamber, the ratio of the walicross-sectional area to the chamber cross-sectional area being approximately l to 1 in the upper part of the mold and the ratio of the wall cross-sectional area to chamber cross-sectional area in the lower part of the mold being substantially greater than but less thanvtwice as great as in the upper portion.

5. A metallic ingot mold, the outer wall surfaces and inner chamber surfaces of which both denne a big-end-up contour, at least two opposed inner surfaces being in at least two sections from bottom to top, the lowermost section, comprising from about 20% to about 50% of the total inner side wall length, being slanted outwardly to a materially greater degree than the adjoining upper wall portions, and the outer surfaces of the mold having an approximately uniform outward slant from bottom to topI the ratio of the.wall cross-sectional area -to the chamber cross-sectional area in the upper part 'of the mold being approximately 1 to 1 and the ratio of the wall cross-sectional area to chamber cross-sectional area in the lower part of the mold being substantially greater than but less than twiceas great as in the upper portion.

6. A metallic ingot mold, the cuter and inner surfaces of which both define a big-end-up contour, at least two opposed inner surfaces having v at least two degrees of slant, the greatest degree being in the lowermost portion, vand the outer surfaces of the mold having an approximatelyv uniform slant, the cross-sectional .area of the walls at the upper portion of the. mold beingV approximately equal to the cross sectionalv area of the chamber at this portion, and the ratio of the wall cross-sectional area to chamber crosssectional area in the lower part of the mold being substantially greater than but less than twice as great as in the upper portion.

f EMIL GATHMANN.