US1719543A - Ingot mold and ingot - Google Patents

Description

July 2, 1929.

E. GATHMANN Filed Oct. 27, 1928 2 Sheets-Sheet 1 Patenta! July 2, 1929.

UNITED STATES PATENT OFFICE.

EHIL GATEMANN, OF BALTIMOBE, MARYLAND.

'INGOT MOID AND INGO'I'.

Application filed October 27, 1928. serial No. 315523.

This invention relates to the casting of metallic ingots and involves certain improvements in the contour and proportional dimensions of the horizontal cross section I of the vertically-extendin mold chamber and of the ingot formed t erein. More es pecially my present invention relates to improvements n the form of mold chambers and ingots shown, described and claimed n my U. S. Patents No. 1,440,535 of January 2, 1923, No. 1,484,940 of February 26, 1924 and No. 1,532,741 of April 7 1925.

As is now well-known to those familiar with the art, an ingot cast in a vertical mold having a. uniformly corrugated dodecagon or twelve-sided cross sectional chamber contour is subject to the formation of fewer surface flaws or defects during solidification than any other form of ingot heretofore known. An ingot of this type, however, in common with other substantially round or oval cm sections, is more or less difficult to handle in the rolling mill and if properly redced requires a greater number of initial mill passes than are necessary in the reduction of an ingot of substantially rectangular cross section of the same' maximum cross sectional dimension in order to insure against tearing of the outer structure at the corner portions of the ingot.

By In present invention I obtain the type of surface solidification characteristic of ingots of the dodecagon type cross section, at the same time retaining the advantages of an ingot of rectangular cross section in reduction of the section during rolling mill Operations. The type of mold made in accordance with my invention has approximately 22% greater Volume for a given maximum dimension of ingot than has the dodecagon type of ingot cross section at present widely used so that it is possible to materially increasethe tonnage of blooms or billets that may be reduced to specified size in a given number of passes.

Another advantage obtained by the employment of my new cross sectional contour over the dodecagon contour resides in the lemened number of molds and shrink head casings required to contain a given charge of molten metal. Furthermore, because of the fewer openings of the ladle stopper necessary for pouring a given heat of steel, there is less liability of trouble, particularly of so-called running stoppers.

My' improvements may be embodied in vertical molds having big-end-up, big-enddown or Parallel chamber walls, for the production of ingots with or without fceder 'or shrink head portions.

In the acconpanyng drawings:

Figure 1 shows a vertical central section of an ingot mold of the big-end-up type fitted with a shrink head casing constructed in accordance with my invention, the plug for the bottom opening being shown in elevation and the stool in section.

Figure 2 is a side elevation of the exterior of a big-end-up mold embodying my improvements of the kind shown in Figure 1.

Figure 3 is a View on an enlarged scale and in section on line 3-3 of Figur-e 1.

Fgure 4 is a View on an enlarged scale and in horizontal section of a quarter portion of the mold shown in F igure 3.

Figure 5 is a perspective view of an ingot fol-med in a mold of the type shown in Figures 1, 2 and 3.

Figura 6 is a perspect-ive view on an enlarged scale of the shrink head casing shown in Figure 1 for forming theupper part of the ingot.

Figure 7 shows on an enlarged scale a.

cross section of the ingot shown in Figure 5.

The mold A is made of cast iron and rests on a stool B having a recess or trough B' of the type shown in my U. S. Patcnt 1,039,725 of October l, 1912.

The inner walls of the mold chamber are shown vertically corr'ugated towards each corner portion, as indicated at C, produeing salients of the type hereinafter described. These corrugations preferahly extend into the necked-in portion of the mold and nerge or disappear therein as shown in Figurel and as shown and claimed in my U. S. Patent No. 1,532.741 of April 7, 1925.

I have found that fewer shrinkage cracks occur in the surface of an ingot during solidification when certain definite angular and radial proportions of the corners and adjacent walls of the mold are employed, and my present invention rclates especially to the horizontal contour and proportions defining the chamber of an ingot mold.

In Figures 1 and 2 of the drawings, lugs O and O' are shown as being cast intcgrally with the mold walls at the upper and lower portions thereof, whereby the mold may be liftcd and manipulated as desired in settin up a jag and in removing the solidifie ingots therefrom.

As shown in Figure 3 the inner walls delining the mold chamber comprise' essentially four prinary side walls D, the walls of each oppositely disposed pair being substantially parallel with each other and each of said walls being disposed at an angle of 90 froni each of the adjaccnt primary side walls; Eight inwardly arched secondary corner walls C are, connected together in pairs by four relatively small outwardly arched primary corner walls E, the walls C being in turn connected to the primary side walls D.

Referring to Figure 4 of the drawings, which shows on an enlarged scale one quadrant of a mold illustrated in Figure 3, D indicates the two primary side walls preferably of relatively straight contour and R indicates the preferred relative length and center of projection of the radius forming the inwardly-arched secondary corner walls C, R being preferably equal to or greater than the line G, which represents somewhat less than half the maximum width or horizontal cross section of the mold chamber at the plane indic'ated by the line 3-3 of Figure 1. It is important for the best contour of mold chamber that the radius R be struck from a center located between the lines L--L' and in proximity thereto as shown at w-y, which lines intersect at the centers Z from which the radii R' forming the primary corner walls E are projected.

The dotted lines T, which indicate the contour of an old type rectangular mold chamber, are parallel to the lines L-L and L' L', which are so located as to intersect at an angle of 90 one with the other at or about the points Z from which the radii forming the primary corner walls E-E are projected. Such contours prevent the forn'ation of reentrant angles at the junction of the secondary corner walls C and primary corner walls E. This is very important as such reentrant angles tend to obstruct free contraction of the skin of an ingot during solidification within the mold.

It will be observed by reference to Figure 4 that lines connecting-each of the Centers from which two adjacent inwardly bellied corner walls are described with the center from which the included outwardly extending salient is described, include an angle of not more than 90. It will also be observed that the primary side walls are connected to the adjacent corner walls by inwardly bellied wall portions which extend at an angle of from 5 to 15 to the adjacent side wall, as llstrated by dotted line V in Figures 4 an The arc defining the corner wall E subtends an angle of more than 45, 'and the are defining the wall F subtends an angle of less than 45, whereby an ingot of substantially rectangular cross section is forned. Neutral shrinkage N-N' and 4.

The exte'ior contour of the mold walls is so designed that the walls are of gradually lesscned thickness from the primary side walls D through the sccondary corner walls C of the mold chamber, having a minimum thickness at the primary corners E, which corners, forming the outer' contour of the mold walls, are preferably shown formed by radii S S'. A With the before mentioned radii and angular proportions, a contour of mold chamber is produced which permits of free shrinkage during solidification of the outer skin or Contacting portion of the solidified ingot without binding, or other physical interference from the mold walls. Furthermore, the thickness or heat absorptive value of the mold is progressively decreased towards the primary corners so that a substantially uniform rate of heat abstraction of the entire mass of the ingot is obtained.

Figure 5 illustrates graphically in perspective an ingot I formed in a mold chamber of the kind shown and above described. The outer portion of said ingot consists of plane or substanitally straight primary side walls D', inwardly-bellied secondary corner walls C' and outwardly-extending prinary corner walls E'. The ingot I is of the big-end-up Gathmann type provided with a shrink head portion W', which preferably has a contour similar to that of the ingot body. It should be understood, however, that my improvements may be embodied, not only in big-end-up, but in any type ot' Vertical ingot whether cquipped with a shrink head portion or not.

Figure 6 illustrates the type of shrink head casing W I preferably empoy, the same having an inner and outer contour similar to the contour of the chamber of the mold body. The shrink head casing is preferably supported on top of the mold so that a portion thereof entel-s the mold chamher.

Unless extreme care is taken in rolling and particularly light reduction passes are employed, the round corrugated ingot heretofore known to the art is frequently torn at the corners before any real work has been done toward reducing the relatively coarse and Weak structure of the ingot as cast. By ny present inprovenents the initial mill passes not only reduce the primary side walls D and the secondary corner walls C, but also the small primary corner walls E, so that the crystalline structure of the metal is worked and refined before any considerable elongation has taken place and tearing of 'the surface is practically eliminated.

It is well-known to those familiar. with the art that the maximum cross section of an ingot is limited by the size of the rolling lines of peripheral are shown n jFgs. 3

mill and the vertical height of the ingot by' V heretofore obtainable.

' It will be observd by reference particularly to Figure 3 that the primary side walls of the mold chamber are quite narrow. It wll also be observed that the mold walls opposte the primary side walls of the mold c amber are relatively thick, and that the mold walls gradually diminish in thickness from the primary side walls toward the outwardly arched corner walls, this construction of the mold walls cooperating with the novel contour of mold chamber 'walls hereinbefore described.

What I claim is: a

1. An ingot mold with a chamber having four Ermary side walls of substantially straig t contour and four outwardly-'arched corner walls and a plurality of secondary corner walls mergng with the primary side walls and said corner walls, the said secondary walls having an inwardly bellied contour, the mold walls gradually diminishing n thickness from the primary side walls toward the outwardly arched corner walls.

2. An ingot mold with a chamber having four primary side walls of substantially straight contour and `four outwardly-arched corner walls and a plurality of secondary corner wallsmerging with the primary si e walls and 'said corner walls, said secondary walls having an inwardly bellied contour and extending at an angle of from 5 to 15 with the primary side wall, the mold walls gradually diminshing inthickness from the primary side walls toward e the outwardly arched corner walls. y

3.7 An ingot mold having a chamber provided with four rimary corner salicnts and four primary si e walls, and a plurality of secondary walls intervening between each primary wall and the corner salients of the chamber, the said secondary walls having an inwardly-bellied contour, the mold walls 'be-. ing constructed to gradually diminish in thickness from the primary side walls toward the corner salients.

4. An ingot having four primary side walls of substantially plane or straight contour and four primary corner walls of outwardly-arched contour, the primary side walls being connected to the adjacent corner walls by inwardly-bellied wall portions which extend at an angle of less than 15 to the adjacent side wall.

5. An ingot of substantially rectangular contour havingfour primary side walls of substantially plane or straight contour and four primary corner walls of outwardlyarched contour, the rimary side walls being connected to the a jacent corner walls by inwardly-bellied wall portions.

t 6. An ingot mold with a chamber of substantially rectangular horizontal cross section having two sets of oppositely-arranged, narrow, and substantially straight or fiat primary walls and four sets of inwardlybellied corner walls, whichare connected to the primary walls and to each other by outwardly-extending salients, lines connecting each of the centers from which the two adj acent inwardly bellied. corner walls are described with the center from which the included outwardly extending salient is described including an angle of not more than 90, the mold walls gradually diminishng in thickness from the side walls to the outwardly extending salients.

7 A mold having an ingot-forming chamber defined by a cross sectional contour consisting of four primary walls of substantially straight contour and eight secondary inwardly-bellied walls and having four outwardly-rounded corner-s or salients, each salient being formed by an are subtending an angle of more than 45, the arc of each of v the inwardly bellied walls subtending an angle of less than 45, the mold walls gradually diminishing in thickness from the prmary walls to the corner salients.

8. A metallic ingot having four substan- `stantially straight primary side walls and of the inwardly-bellied walls subtending an angle of less than 45. I

In testimony whereof, I have hereunto subscribed my name.

EMIL GATIMANN.

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