US1819365A - Mold - Google Patents

Description

Aug. 18, 1931. FlRTH 1,819,365

MOLD y Filed Nov. 2. 1929 lai i lai i I 'i 2a i 9 \Il 7 6 5 1 1 L 1V s ii z r "i I i PatentedV Aug.. 18,

impurities and gases.

UNITED STATES PATENT- ori-fica PENNSYLVANIA GERALD rm'm, or PITTSBURGH, rmmmvmn, assIeNfoa1ro rmrmsrm .Lum STEEL conm, or mxnrsronr, PENNSYLVANIA, acoaromrroiror nom appuminmea november-2, 192s. serial no. 404,468. 'y Y This invention relates to molds for casting metal and to a method whereby metallic bodies may be formed which are substan'- tially free from shrinks, pipes, segregated IngotsofV metal such as steel ordinarily are cast in vertical molds. These molds usually are provided with hottops which de.

crease the tendency towards shrinking and 30 piping by maintaining the top of the ingot pipes and segregated impurities and is usually discarded. For some purposes, however,

. where it is desired to produce a metallic body the topbut also cools inwardly towards its line II-II of Figure 1;

which is substantially free fromsegregated impurities, the method of discardin the u per portion ofthe ingot doesnot s ce. e ingot not only cools from the bottom toward centei'; that is, the outside of the ingot in contact with the mold cools first and there is a pro essive coolin toward the center so that t e last rtion 1n each horizontal plane through the ingot which cools is the center.

Itis probable that' the central 5% to 15% of this cross section cools almost simultaneously; that is, the 'solidifrcation is progressive 1nwardly from'the sides of the mold up to a central point, after which oint more or less simultaneous freezing ta es place. It is this central 5% to 15% which contains the greater art of the segregated impurities and gases. erefore, even if the top portion of the ot is discarded there is a central core coinlclident with the longitudinal axis of the ingot .which contains .some segregated impurities. It is impractical` under present practice todiscard the whole of that central axis or core which extends from the bottom to the top of the ingot and which contains the steel last to cool in each horizontal plane.

In accordance with my invention, the metal is cast in a mold having a portion provided with insulating material. The portion of the ingot cast adjacentto the insulated portion of the mold accordingly cools more slowly than the rest of the ingot, and this portion whichwas the last to cool containsthe Igreater i portion of thesegregatedA impurities.

In the preferred embodiment of m invent1on,a relativelyV long narrow mol is employed'having one end provided with heat insulation. The metalis poured into the mold at the insulated end. The insulation retards the cooling of the metal at one end,

but allows relatively rapid cooling at the other end. The segregated impurities collect principally in the insulated end ofthe mold, leaving the opposite end substantially free from such defects.Y After cooling, the..

end of the ingot containing. the segregated of the ingot. In the accompanyin drawings which illustrate two present pre erred embodiments of my mvention, v

Figure 1 isa side elevation of an ingot mold;

Figure 2 isa horizontal section on the Figure 3 is a vertical side elevation of a modified form ofingot mold, and

Figure ,4 isa horizontal section on the provided at its left-hand end, as viewed in- Figure 2, with alin' 5 of refractory heatinsulating material. e opposite or righthand end of the mold, as viewed in Figure 3, has no insulation, but on the contrary the metal in this end-of the mold is rapidly cooled by contact with the walls of the mold.

Referring to the embodiment illustrated in Figures 3 and 4, the arrangement differs from that shown in Figures 1 and 2 only in that the mold 2ais made in two parts, 6 and 7, which are secured together by bolts 8. The left-hand end of the mold 2a is provided with a refracto heat-insulating material 5a.

In practicing the invention, the metal is preferably ured through the hot top into tlie mold, a though, if desired, the hot top may be omitted. Insulating material 5 or purities is separated from the remainder i After the ingot has cooled, the portion 11 which is substantially free from segregated impurities is'separated from the portion 12. The Yportion 11 is thereafter rolled or otherwise worked according to usual practice.

From the above description, it will be seen that in accordance with my method that portion in each horizontal plane through the ingot which was last to cool and which contains segregated impurities and shrinks is discarded and that the remaining portion of .the ingot in each horizontal plane is substantially free from such defects. Under ordina'ry practice heretofore known, the last portion of the ingot to cool in each horizontal plane is inthe center of the ingot and for this reason it was impracticable to discard this portion.

In accordance with my invention, the portion 0f the ingot which is last to cool in each `horizontal plane 1s preferably located at one end of the ingot so that this portion which was last to cool and which contains the segregated impurities and shrinks may be separated from the remaining portion of the ingot which is substantially free from the above defects. Y

I have villustrated and described two present preferred embodiments of the invention. It is to be understood, however, that the invention may be otherwise embodied or practiced within the scope of the following claims.

I claim: Y

1. A substantially rectangular mold having walls of good heat conducting properties, and a lining of refractory heat insulating material in one end of the mold, said lining covering one end wall and a portion of the adjacent side walls. 2. A mold provided with a pouring openingk and having a layer of insulating material on the end wall and a portion of the adjoining side Walls of the mold adjacent the opening.

8. A relatively long narrow ingot mold having a pouring opening adjacent one end thereof, the end and side walls of the mold at the end adjacent the pouring opening having a lining of insulating material which maintains the metal at that end hot for a longer time than the remainder of the metal and causes the segregation and shrinks to forni in the insulated end of the mold.

1. A mold having Walls of good heat conducting properties, one end wall and a portion of the adjoining side walls being lined with insulating material.

5: A m'old provided with a pouring opening, the end wall adjacent the pouring opening, and a portion of the adjoining side Walls having greater heat insulation properties than the opposite end wall and portions of the side walls adjacent said opposite end whereof I have hereunto set

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