Patented Apr. 7, 1925.
v UNITED STATES PATENT: OFFICE.
EMIL GATHMANN, 0F BALTIMORE, MARYLAND, ASSIGNOR TO THE GATHMANN ENGINEERING COIPANY, OI BALTIMORE, MARYLAND, A CORPORATION OF MARYLAND.
Application filed August 20, 1923. Serial No. 658,370.
To all whom it may concern:
Be it known that I, EMIL GATHMANN, a citizen of the United States, residing in Baltimore, State of Maryland, have invented certain new and useful Improvements in Ingot Molds, of which the following is a specification.
This invention relates particularly to the casting of ingots from either steel which has been deoxidized as much as possible, or from partially deoxidized steel, and it involves certain improvements in the shape or contour of the mold chamber and of the ingot formed therein.'
More especially my present invention relates to the form ofthe mold chamber'for casting and shaping ingots in the manner shown, described, and claimed in my United State Patents No. 1,440,535 of Jan. 2, 1923, and No. 1,455,197 of May 15, 1923.
One object of the invention is to so construct or shape the mold chamber that the ingot formed therein may have such shape that it may be withdrawn from contactwith the walls of the chamber without undue or harmful stressing of the outer walls of the ingot, and which is better adapted for rolling or reduction when reheated.
The horizontal contour of the mold chamber is similar to that shown in my patent of January 2, 1923, but differs therefrom in certain particulars hereinafter specified.
My improvements may be embodied in either big-end-up or big-end-down molds as will hereinafter more clearly appear. a
In the accompanying drawings Figure 1 shows a vertical section of an ingot mold of the big-end-down type, constructed according to my'invention.
Figure 2 isa view on an enlarged scale and in section on the line 2-2 of Figure 1.
Figure 3 is a view partly in side elevation and partly 'in'vel'tical section of a mold emhedging my improvements of the big-end-up lIl Figure 4 is a perspective view of a portion of an ingot formed in molds such as shown in Figures'l and 2.
The mold proper A shown in Figure 1 rests on a stool B preferably having a recess B in which the lower part of the ingot iscast. The upper end of the mold chamber C is preferably contracted or necked-in at X. The inner walls of the mold chamber are shown corrugated vertically, as indicated at y in Figure 1, producing salients of the kind hereinafter explained. These corrugations preferably extend into the neckedin portion of the mold and merge or disappear therein as shown.
The mold shown in Figure 3 is a big-endup mold. The necked-in or contracted part of the mold chamber is at the bottom of the mold instead of at the top. In this case there is an opening in the bottom of the mold closed by a plug D, which extends into a hole in the stool B. This plug, in addition to closingv the bottom of the mold chamber, is of service in stripping the ingotfrom the mold.
In ordinary practice, after the ingot has been formed in its mold and stripped therefrom, it is reheated in a soaking pit or furnace. When taken from the pit at suitable temperature for desired reduction of its cross section, an ingot is merely a heated steel casting and is relatively tender and liable to surface cracks or splits if subjected to any heavy blows or severe stresses. The initial working, either by rolls, presses, hammers or otherwise, should, thus be of such graded intensity that the metal is not elongated or stretched to any dangerous extent particularly on the surface not being acted on directly by the reducing means in the initial passes or reductions by the rolls, press or hammers. Rapid reduction of area is not as harmful as rapid elongation or stretching of the sides of the raw steel.
ingot casting during its initial working into a forged product. An initial overworking by reduction of area of two sides will cause the sides that are not being Worked and directly compacted to tear and crack, which tears and cracks cannot be healed by any subsequent Working or reduction of area of these damaged surfaces. The original contour of the cross section of the ingot surface is, therefdre, most'important, as it regulat'es or determines the amount of permissible initial elongation of the free or an worked sides of the raw ingot casting in the initial reductions of area and elongatlon of said casting.
In my patent of'January 2, 1923 above referred to I have shown ingot molds for producing corrugated ingots of novel construction, and reference is made to this patent for a full explanation of the advantages obtained by the construction and methods therein described.
I have found by much. thought and many experiments that the products of the molds may be considerably improved by giving to the mold chamber certain definite shape or configuration which will be presently explained.
The mold shown in Figure 1 is most useful in the formation of ingots made from eii'ervescing, rising or semi-piping steels, while the mold shown in Figure 3 is most useful for forming ingots made of the well- I deoxidized or degasified steels.
The general kind of mold cavity now employed by me is similar to that shown in my patent of January 2, 1923. I have found, however, that certain refinements and modifications of this kind of mold cavity are advantageous, especially the gradually tapering or merging of the salients into the necked-in portion of the mold chamber,
either of the big-end-up or the big-end-down type, as shown respectively in Figures 1 and 3 of the drawings. I have also found that the angular relations of the salients to the primary faces and secondary or corner faces of the mold chamber or ingot contour should be substantially as shown in Figure 2, namely, the angle of the salients should be relatively smaller where they merge into the primary faces and into the secondary or corner faces and as shown inv Figure 2 these angles should be somewhere between 2 and 10 in order to obtain the best results not only in molding but in rolling the ingot.
As shown in Figure 2 the mold chamber has four primary walls or sides 0;, and eight secondary walls or salients b, the secondary walls being connected to the primary walls by arc shaped parts or salients 0. Each secondary wall 1; extends at an angle of from 5 to 15 from a tangent T connecting the two apexes of the salient of each primary wall.
The'advantage of this construction is that the corners of the secondary walls where they join the salients are better acted upon by the rolls in reduction of the ingot in the initial passes, better insuring the absence of breaks or cracks during the reduction operation.
It will be also observed that the mold is so constructed that it has primary side walls,
which preferably have a convex contour,
and the secondary walls forming the widened corners having curved salients intermediate the seoondary and primary walls, the arc of each salient being subtended by an angle considerably greater than 90- W ion the corner angle is 90 or less and a small radius is used, upon reheating the ingot preliminary to rolling there is liability of the sharp corners of the ingot being burned, whereas if they aresu-bte-nded by an angle greater than 90, for instance by 95 or larger angles, no sharp or narrow corners are present and, therefore, where the salients are subtended by an obtuse angle, the corners are so wide that they are not apt to burn; and hence are not liable to crack. In the mold shown there are four primary side walls and widened corners or outwardly extending salients intervening between the side walls, the primary walls be ing of convex contour, and a line connecting the ends of each primary side wall or the apexesof two connected salients being disposed at an angle of from 2.to 10 to the adjacent end portion of the adjacent convex primary wall, that is to say, the angle between a line drawn from the two apexes of a primary side wall is disposed at an angle of from 2 to 10 to a line connecting one of the apexes to the middle point of the arc of the primary wall.
While in general the shape of the mold chamber shown in the drawings is similar to that shown in my patent of Jan. 2, 1923, there are certain specified differences by means of which improved results are obtained. The novel points are set forth in the claims.
Figure 2 of the drawings shows a cross section of the mold shown in Figure 1, the mold shown in Figure 3 having the same cross section. In both cases the corrugations merge into the reduced or necked-in part of the mold chamber.
Figure 4: is a perspective View of an ingot of the kind produced in a mold having a chamber cross section such as shown in Figure 2. The ingot I has four concave salients i, the salients projecting inwardly, and eight secondary walls 71 at the corners, the secondary Walls being connected with each other by outwardly extending curved salients i and with the primary walls by outwardly projecting curved salients i Ingots as shown in Figure 4 may be. re-
heated with little or no danger of burning rugations extend and merge.
2. An ingot mold having a chamber formed with corrugated side walls and with a necked-in portion at the top into which the corrugations extend and merge.
3. An ingot mold having a, chamber formed with corrugated side walls and with a necked-in portion at the bottom into which the corrugations extend and merge.
4. An ingot mold having a, chamber formed with corrugated side walls and a necked-in portion at the top into which the corrugations extend and merge in combination with a. stool having :1, races in its lower end in which the lower portion of the ingot 1 is cast.
In testimony whereof, I have hereunto subscribed my name.
EMIL GATHMAN N.