US2240396A - Ingot mold and ingot - Google Patents

Description

April 29, 1941. E. GATHMANN INGOT MOLD AND INGOT 2 Sheets-Sheet 1 Filed Jan. 2'7, 1941 Emil Ciafhmann 62%; vw fi Ap il 29, 1941- E. GATHMANN 2,240,396

INGO'I MOLD AND INGOT Filed Jan. 27, 1941 2 Sheets-Sheet 2 WW I 2' Emil Gafhmann r flww'n dy f AW,

Patented Apr. 29, 1941 INGOT MOLD AND INGOT Emil Gathmann, Baltimore, Md., assignor t0 Gathmann Research Incorporated, Catonsville, Baltimore, Md., a corporation of Maryland Application January 27, 1941, Serial No. 376,221

8 Claims.

This invention relates to ingot molds and ingots, and more particularly to improvements in cross sectional contours of ingot mold chambers andingots.

It is now well known to those skilled in the art that the metal of ingots of generally rectangular cross section may be more effectively worked during initial roll passes if the mid-portions of their sides are provided with projecting salient portions'which are adapted to be sWedged outwardly, and to a large extent parallel with the axes of the rolls, rather than flowed longitudinally as happens in ingots of rectangular cross section the sides of which are not provided with such projecting salients. An ingot having a contour including such outwardly projecting surfaces at the edges of relatively narrow primary side portions is disclosed and claimed in my United States Patent 1,745,089 of January 8, 1930. The ingot described in this patent includes medial primary side portions each comprising two outwardly extending initially roll contacting convex salients connected by a single inwardly bellied or curved primary side portion. In my United States Patent 1,767,174 of June 24, 1930, there is described and claimed an ingot including primary or initially roll contacting side portions comprising a plurality of alternate smoothly curved inwardly bellied and outwardly bellied corrugations.

These known contours have provided advantages in the solidification and rolling of ingots but some difficulty has been experienced with ingots having prior art contours because of the formation of cracks, usually subcutaneous cracks,

connected along its opposite side edges respectively with relatively smoothly curved concave portions which, at any cross section of the ingot,

are defined by arcs having substantially a common center lying substantially on the neutral line of peripheral shrinkage generally normal to the primary side portion. Thus, the two smoothly curved concave portions of each primary side respectively form spaced .segments of the same circle, the relatively abruptly curved convex portion intervening between the two segments.

The numerous and complex factors influencing the behavior of steel in solidifying and cooling, and in being reduced by rolling processes, are not all understood entirely and the beneficial effects upon the final rolled product produced by employing contours of the character referred to therefore cannot be explained categorically. The improved results possibly are due to the particular formation of ingot metal crystals induced by the chilling mold walls having contours complementary to the ingot surface contour described above which apparently strengthens the ingot locally at the zone in which cracks heretofore have been troublesome; but it is possible that the novel ingot contour causes the application of sub-cutaneous rolling pressure in such a direction or directions as to avoid tearing or pulling apart of the metal, 7

Another object of the invention is to provide an ingot and mold for producing the same which have contours characterized as explained above. More specific objects will become apparent from a reading of the following detailed description, the appended! claims, and the accompanying drawings, in which:

Figure 1 is a central vertical sectional view of an ingot mold embodying the invention;

Figure 2 is a horizontal half section taken on the line 2-2 of Figure 1;

Figure 3 is a somewhat diagrammatic partial horizontal section taken on the line 2-2 of Figure 1 and drawn on an enlarged scale;

Figure 4 is a perspective view of an ingot embodying the invention and having the contour complementary to the mold contour disclosed in Figures 1, 2 and 3;

Figure 5 is a horizontal sectional view'of the ingot shown in Figure 4 and drawn on a slightly enlarged scale;

Figure 6 is a horizontal sectional view of another form of ingot embodying the invention; and

Figure 7 is a fragmentary horizontal and somewhat diagrammatic cross sectional view of an ingot mold having a contour complementary to the contour of the ingot shown in Figure 6.

The invention may be embodied in various classes of molds and ingots. Generally stated, most commercial ingots are cast in vertically extending molds which taper outwardly from bottom to top (big-end-up molds) or taper outwardly from top to bottom (big-end-down molds). The largest tonnage of high grade or quality steel is produced in big-end-up molds and the invention is illustrated as being embodied in a big-endup mold and ingot. However, it will be apparent from the following description that the invention may also be embodied in molds and ingots differing as to those characteristics of contour at the upper and lower extremities thereof for facilitating the handling of the mold when setting up a jag of molds and when removing ingots from the molds. The inwardly tapering side and corner walls of the mold chamber merge at their bottoms with a vconcavo-convex neckedin bottom portion B which may have a contour in vertical section somewhat similar to that disclosed in my Patent 2,047,098 of July 7, 1936. The mold bottom wall is formed with the usual bottom opening 0 which receives a sealing or stripping plug P.

As is well known, ingots which are cast on end or in vertical position may be similar or symmetrical as to all four sides or they may be in the form of slabs in which the two wider sides correspond with each other in outline and the narrower sides are different from the wider sides but correspond with each other. The mold shown in Figures 1 to 3, inclusive, has an ingot forming chamber or matrix of generally rectangular cross section the center lines of which are inidcated at T -T and T -T The mold chamber is defined by four concave corner-walls I defined by arcs having radii R whose centers are at C All four side walls of the mold chamber are of the same contour so that a detailed description of one side wall and its connection with the adjacent corner walls will be sufiicient. Generally stated, the side walls comprise all of the wall surface intervening between the concave corners I. Each of the side walls so considered is formed of a plurality. of sections or portions having relative dispositions, curvatures, and extents which have been found in tests and in commercial production to eliminate the subnormal to the side wall considered as a whole.

The opposite edges of the concave wall portion 2 merge with abruptly convex wall portions 3-3 defined by arcs whose radii R -R respectively have their centers C -C lying outwardly 'beyond the side wall and being disposed relatively on opposite sides of the transverse center line T -T The relatively abruptly curved convex wall portions 3-3 merge respectively with relatively smoothly curved convex wall portions di defined by arcs whose radii IV -R have substantially a common center C lying substantially on the transverse center line T -T The wall portions dl merge respectively with outwardly projecting primary side wall marginal portions 5-5. In the mold shown in Figures 1., 2 and 3 the outwardly projecting marginal wall portions 5-5 are curved concavely and are defined by arcs whose radii R -R have their centers at C -C within the mold chamber. The curvature of the outwardly projecting marginal wall portions 5-5 is not per so an essential feature of the present invention, the provision of curved wall portions at this point depending upon the size of the mold. The contour shown in Figures 1, 2 and 3 is one which has been found to produce improved results in the use of a mold the maximum cross sectional dimension of which is approximately fifteen inches. As will beexplained with reference to Figures 6 and 7, it may be desirable, when using larger molds, to provide fiat marginal portions at the edges of the primary side walls. The marginal portions 5-5 are flanked, respectively, by secondary corner walls 6-6 which in turn merge with the adjacent corner walls I-l and which, in extending from the wall portions 5-5 to the corners l-i, slant or incline toward the transverse center line T -T the arrangement being such that the primary side wall constituted by the concave portion 2, the convex portions 3-3, the convex portions 4-4, and the marginal portions 5-5 is disposed outwardly away from the center line T -T more than the secondary corner walls 6-6 and the primary corners I-l. Thus, an ingot cast in the mold will have a side surface contour such that the metal at and under the primary side surface corresponding to the mold primary side wall portion constituted as set forth above will be subjected to the initial rolling pressure.

' An important feature of the present invention is the provision of the relatively smoothly curved convex mold wall portions 4-4 which are struck from the common center C on or substantially on the transverse center line T -T and which both form segments of the periphery of the same circle. Thus, as indicated by the dotted arcuate line IV in Figure 3, each smoothly curved convex wall portion 4 is a. continuation of the other wall portion 4. In accordance with another feature of the invention the radius R of each relatively smoothly curved convex wall portion 4 is substantially greater than the radius R of the relatively abruptly curved concave wall portion 2 and also is substantially greater than the radii R of the relatively abruptly curved convex wall portions 3. The ratio of the radius BA to the radius R and to each of the radii R should not be less than four to one and it should be greater than four to one in most cases, particularly in the larger mold sizes. The mold shown in Figures 1 to 3, inclusive, has a maximum width of approximately fifteen inches and the radius R is about eleven times as long as the radius R and about eleven times as long as each of the radii R -R This construction provides a relatively deep salient on the neutral line of shrinkage of the ingot cast in the mold and provides a very gradual slope to the marginal portions of the primary side surface of the ingot. The abrupt change of direction provided by the acutely curved convex portions 3-3 and concave portion 2 provides a correspondingly abrupt outwardly extending salient on the ingot lying on the neutral line of shrinkage.

Preferably the root or bottom of the depression formed by the concave mold wall part 2 is disposed a little inwardly of the outermost portions of the marginal walls (i-ii. An ingot cast in a mold so formed and having a corresponding or complementary contour will not cause dimculty sometimes encountered when as many as three outwardly extending ingot salients are designed for initial contact with the rolls. In conventional ingots having a multiplicity of outwardly extending salients intended to be aligned, the projection of a central salient outwardly a little more than is intended results in rocking or canting of the ingot in the rolls and consequent diamond-shaping in reduction. The arrangement of the concave wall portion 2 inwardly of the marginal wall portions as described above obviates such difllculties in rolling as is described in more detail in my Patent 1,810,041 of June 16, 1931..

The mold shown by way of example is substantially rectangular in cross section, having its four primary side portions arranged in two pairs with the primary side portions of each pair being disposed opposite each other.

An ingot produced in a mold such as disclosed in Figures 1, 2 and 3 will have a contour generally complementary to or corresponding with the mold wall contour described above. Such an ingot I is shown in Figures 4 and 5 and the various ingot surface portions are designated by the same numerals as those which designate corresponding wall portions of the mold with the exception that the numerals designating the ingot surface portions are primed. Thus, each of the primary ingot sides includes an outwardly projecting relatively abruptly curved convex central portion 2, the opposite longitudinal edges of which merge with relatively abruptly curved concave portions 3-3, which in turn merge with relatively smoothly curved concave portions 4'-4' which are flanked by outwardly projecting convex marginal portions 5-5'. The outwardly projecting portion 5' at each marginal edge of the primary side surface is connected to the adjacent primary corner I by an inwardly slanting or inclined concave secondary corner portion 6.

The radius of the smoothly curved convex portions 4'-47 is located on or substantially on the neutral line of peripheral shrinkage N N normal to the side surface as a whole and is substantially longer than the radii of the abruptly curved concave portions 3-3, which latter radii have their centers on opposite sides of the neutral line of shrinkage N N and also is substantially longer than the radius of the abruptly,

curved convex central portion 2', which has its center on the line of peripheral shrinkage N --N within the ingot. These various radii are not indicated in Figures 4 and 5, but theyhave the same relation to each other as the radii of the corresponding wall portions of the mold as shown in detail in Figure 3. The other neutral line of shrinkage is indicated at N N It will be observed that the relatively smoothly curved concave side surface portions 4-4' of the ingot form segments of the same circle as is indicated by the ure 5.

Figure 7 shows a horizontal half section of a mold m with center lines t -t and t and dotted connecting line IV' in'Fighaving a contour more especially suited to molds larger than the mold illustrated in Figures: 1, 2, and 3. The contour of the mold shown in Figure 'Iis suchas has been found to produce good results for molds having a maximum cross sectional dimension of approximately nineteen inches. The marginal primary sidewall portions I05-I05 are flat but otherwise the arrangement of concave and convex portions and the relative lengths of the radii of such portions is generally similar to that of the mold shown in Figures 1,

2 and 3. Thus, the mold. shown in Figure 7 includes a relatively abruptly curved concave central wall portion I02 whose opposite edges merge with relativelyabruptly curved convex wall portions I03I03 which in turn merge respectively with relatively smoothly curved convex wall portions I04-I04 connected at their outer ends to the flat marginal portions I05I05. Each marginal portion I05 is joined to the adjacent primary corner wall MI by an inwardly slanting or inclined convex secondary corner wall I06. The radius of the relatively smoothly curved convex wall portions I04 is about twenty-six times as long as the radii of the abruptlyjcurved convex portions I03-I03 and about twenty-six times as long as the abruptly curved concave portion I02. The centers of the arcs defining the several curved portions I02, I03 and I04 are located similarly to the centers of corresponding wall portions of the mold shown in Figures 1, 2 and 3. The drawings do not include a vertical sectional view of the mold shown in Figure 7, but this mold may have any suitable vertical sectional contour such, for example, as that shown in Figure 1.

Figure 6 shows an ingot i such as would be cast in the mold shown in Figure 7 and which, therefore, would have a contour complementary to or corresponding with that shown in Figure 7. The neutral lines of shrinkage are indicated at n -n and n n Each ingot primary side surface includes an abruptly curved convex central portion I02 flanked by abruptly curved concave portions I03'I03 which merge, respectively, with relatively smoothly curved concave portions l04'-l04 jointed at their outer extremities to the fiat marginal portions I05I 05'. Each marginal portion I05 is connected to the adjacent primary corner IOI' by an inwardly slanting concave secondary corner portion I06. The relative lengths of the radii of the curved portions 7 of the mold wall portions and ingot surface por-,

tions are substantially the same at all cross sections of the mold and ingot main bodies, the only 1 substantial variation in' these relations being in the short necked-in bottoms oihthe mold chamfl I bers and ingots. e I

The mold and ingots disclosed her'ein 'have contours or are formed with contours embodying theinvention and have bensucces'sful in the elimination of a very large part of the difficulty previously encountered when using prior art molds and ingots having generally rectangular cross sections and comprising various types 'of fluted or corrugated primary sides. As to the two sizes of molds and ingots disclosed by way of example, the relative dispositions, curvatures and extents ofthe primary mold wall portions and primary ingot surfacelportions are nowpreferred. It will be understood, however, that'some changes may be made in the'contours disclosed herein without departing .from the invention as defined in the claims.

I claim: a 1. A metallic ingot having two oppositely disposed primary side portions each of which comprises longitudinally extending outwardly projecting marginal portions, a longitudinally extending relatively abruptly curved convex central. portion which, at any cross section of the ingot, is definedby an are having its center substantially on the neutral line of shrinkage generally normal to said primary side portion, two relatively smoothly curved concave portions respectively connected to said marginali portions and-extending toward said central portion, and two relatively abruptly curved concave portions respectively interposed between andconnecting the opposite longitudinal edgesof said central portion with said relatively smoothly curved concave portions, said relatively smoothly curved concave portions, at any cross section of the ingot, being defined by arcs having substantially a common center lying substantially on said neutral line of shrinkage, and said relatively abruptly curved concave portions at any cross section of the ingot, being defined by arcs having their respective centers on opposite sides of said neutral line of shrinkage.

2. A metallic ingot having two oppositely disposed primary side portions each of which comprises longitudinally extending outwardly projecting marginal portions, a longitudinally extending relatively abruptly curved convex central portion which, at any cross section of the ingot, is defined by an are having its center substantially on the neutral line (if shrinkage generally normal to said primary side portion, two relatively smoothly curved concave portions respectively connected to said marginal portions and extending toward said central portion, and two relatively abruptly curved concave portions re- I spectively interposed between and connecting the opposite longitudinal edges of said central portion with said relatively smoothly curved concave portions, said relatively smoothly curved concave portions, at any cross section of the ingot, being defined by arcs having substantially a common center lying substantially on said neutral line of shrinkage, and said relatively abruptly curved concave portions at any cross section of the ingot, being defined by arcs having their respective centers on opposite sides of said neutral line of shrinkage, the radii of the arcs defin ing said relatively smoothly curved concave portimes longer than the radii of the arcs defining said convex central portion and said relatively abruptly curved concave portions at said cross section.

3. An ingot mold having two oppositely disposed primary side wall portions each of which comprises longitudinally extending outwardly projecting marginal wall portions, alongitudinally extending relatively abruptly curved concave wall portion which, at any cross section of the mold, is defined by an are having its center substantially on the mold transverse center line normal to said primary side wall portion, two relatively smoothly curved convexwa'll portions respectively connected to said marginal wall portions and extending toward said central wall substantially on said transverse center line, and said relatively abruptly curved convex wall portions at any cross sectionbeing defined by arcs having their respective centers on opposite sides of said transverse center line.

4. An ingot mold having two oppositely disposed primary side wall portions each of which comprises longitudinally extending outwardly projecting marginal wall portions, a longitudinally extending relatively abruptly curved concave wall portion which. at any cross section of the, mold, is defined by an are having its center substantially on the mold transverse center, line normal-to said primary side wall portion, two

relatively smoothly curved convex wall portions relatively abruptly curved convex wall portions,

at any cross section being defined by arcs having their respective centers on opposite sides of said transverse center line,- the radii of the arcs defining said relatively smoothly curved convex wall portions at any cross section being at least four times longer than the radii of the arcs defining said concave central wall portion and said,

relatively abruptly curved convex portions at said-cross section.

5. A metallic ingot of generally rectangular cross section having four primary side portions which are arranged in pairs with the primary side portions of each pair disposed opposite each other, each of said Primary side portions comprising longitudinally extending outwardly proiecting marginal portions, a longitudinally extending relatively abruptly curved convex central portion which, at any cross section of the ingot,

is defined by an are having its center substantially on the neutral line 0! shrinkage generally normal to said primary side portion, two relatively smoothly curved concave portions respectively connected to said marginal portions and extendin toward said central portion, and two relatively abruptly curved concave portions respectively interposed between and connecting the opposite longitudinal edges of said central portion with said relatively snioothly curved concaveportions, said relatively smoothly curved concave portions, at any cross section or the ingot, 'being defined by arcs having substantially a common center lying substantially on'said neutral portion, and two relativelyabruptly curved convex wall portions respectively interposed between and connecting the opposite longitudinal edges of said central wall portion with said relatively line of shrinkage, and said relatively abruptly curved concave portions at any cross section of the ingot, being defined by arcs having their respective centers on opposite sides of said neutral line of shrinkage. x

6. A metallic ingot of generally rectangular cross section having four primary side portions which are arranged in pairs with the primary side portions of each pair disposed opposite each other, each of said primary side portions comprising longitudinally extending outwardly projecting marginal portions, a longitudinally extending relatively abruptly curved convex central portion which, at any cross section or the ingot, is defined by an are having its center substantially on the neutral line af shrinkage generally normal to said primary side portion, two relatively smoothly curved concave portions respectively connected to said marginal portions and extending toward said central portion, and two relatively abruptly curved concave portions respectively interposed between and connecting the opposite longitudinal edges of said central portion with said relatively smoothly curved concave portions, said relatively smoothly curved concave portions, at any cross section of the ingot, being defined by arcs having substantially a common center lying substantially on said neutral line of shrinkage, and said relatively abruptly curved concave portions at any cross section of the ingot, being defined by arcs having their respective centers on opposite sides of said neutral line of shrinkage, the radii of the arcs defining said relatively-smoothly curved concave portions at any cross section being at least four times longer than the radii of the arcs defining said convex central portion and said relatively abruptly curved concave portions at said cross section.

7. An ingot mold of generally rectangular cross section having four primary side wall portions which are arranged in pairs with the primary side wall portions of each pair disposed opposite each other, each of said primary side wall portions comprising longitudinally extending outwardly projecting marginal wall portions, a longitudinally extending relatively abruptly curved concave wall portion which, at any cross section of the mold, is defined by an arc having its center substantially on the mold transverse center line normal to said primary side wall portion, two relatively smoothly curved convex wall portions respectively connected to said marginal wall portions and extending toward said central wall portion, and two relatively abruptly curved convex wall portions respectively interposed between and connecting the opposite longitudinal edges of said central wall portion with said relatively smoothly curved convex wall portions, said relatively smoothly curved convex wall portions, at any cross section of the mold, being defined by arcs having substantially a common center lying substantially on said transverse center line, and said relatively abruptly curved convex wall portions at any cross section being defined by arcs having their respective centers on opposite sides of said transverse center line.

8. An ingot mold of generally rectangular cross section having four primary side wall portions which are arranged in pairs with the primary side wall portions of each pair disposed opposite each other, each of said primary side wall portions comprising longitudinally extending outwardly projecting marginal wall portions, a longitudinally extending relatively abruptly curved concave wall portion which, at any cross section of the mold, is defined by an are having its center substantially on the mold transverse center line normal to said primary side wall portion, two relatively smoothly curved convex wall portions respectively connected to said marginal wall portions and extending toward said central wall portion, and two relatively abruptly curved convex wall portions respectively interposed between and connecting the opposite longitudinal edges of said central wall portion with said relatively smoothly curved convex wall portions, said relatively smoothly curved convex wall portions, at any cross section of the mold, being defined by arcs having substantially a common center lying substantially on said transverse center line, and said relatively abruptly curved convex wall portions at any cross section being defined by arcs having their respective centers on opposite sides of said transverse center line, the radii of the arcs defining said relatively smoothly curved convex wall portions at any cross section being at least four times longer than the radii of the arcs defining said concave central wall portion and said relatively abruptly curved convex portions at said cross section.

EMIL GATHMANN.

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