US3287772A - T-shaped external chill - Google Patents

Description

1966 A. P. STEINHAUSER T-SHAPED EXTERNAL CHILL Filed May 8, 1964 'center of the mass.

United States Patent 3,287,772 T-SHAPED EXTERNAL CHILL Aloysius P. Steinhauser, Granite City, 11]., assignor to Amsted Industries Incorporated, Chicago, 111., a corporation of New Jersey Filed May 8, 1964, Ser. No. 365,999

Claims. (Cl. 22-174) This invention relates to casting molten metal in sand molds and, more particularly, to an external chill for controlling the rate of cooling and shrinkage of a casting so as to obtain uniform solidification thereof.

When molten metal is poured in a mold cavity, the periphery of the mass of metal solidifies before the central part to form a rigid outer shell. The molten metal within the shell then cools, and hence solidifies, inwardly from the shell, tending to cause shrinkage away from the In the case of castings which are formed with isolated sections that are heavier than adjoining parts, e.g., those including crosses, angles, TS, and Ys, cracks and voids are frequently formed because by the time the metal at the center of the mass reaches solidification temperature, there is insufficient metal to fill the space defined by the already solidified shell.

Attempts to overcome the formation of these defects in castings include the utilization of so-called chills. The chills, which may be of either the external or internal types, promote directional solidification and reduce the elfect of severe temperature gradients caused by sharp changes in metal sections of the castings. In general, internal chills are more effective than external chills but suffer from the disadvantage that extreme care must be taken in locating them. External chills, which are fabricated of a metal having a high heat capacity and conductivity, are positioned so that they form a flush surface with the wall of the sand mold or core. When molten metal is cast, the met-a1 that contacts the chill plate cools at a different rate than the metal that contacts the sand so as to produce the desired surface hardening and other directional heat flow required as the casting sets up.

While the utilization of external chills reduces the number of castings which are formed with defects, an undesirable high number of castings are still formed with cracks and/or voids, as at intersecting ribs, walls, etc. As for example, a light pressed steel chill is usually effective in eliminating cracks, but, however, does not in all cases eliminate voids within the casting. In contradistinction, when a solid forged or cast chill is used, many castings crack at the edge of the chill due to the severity of the effect of the chills mass.

This invention is based on external chills which are comprised of an elongated plate section from which a longitudinal cooling fin extends so that the chills have somewhat of a T-shaped cross-section. The provision of the cooling fin changes the effect of the chill plate so that the chills of this invention are more elfective than conventional chills in eliminating cracks and voids in castings. These chills are used in cores and molds, and can be easily produced from rolled T bars.

It is, therefore, a primary object of this invention to provide an apparatus for obtaining uniformsolidification of castings.

Another object of this invention is to provide an external ohill which is substantially T-shaped in crosssection.

Still another object of this invention is to provide an external chill including a longitudinal cooling fin extending therefrom.

These and further objects of this invention will become apparent or be described as the description thereof herein proceeds and reference is made to the accompanying drawings in which:

3,287,772 Patented Nov. 29, 1966 FIGURE 1 is a rear elevation showing the preferred embodiment of the cooling fin;

FIGURE 2 is an end view of the chill illustrated in FIGURE 1; and

FIGURES 3 and 4 are sectional views through the planes 33 and 4-4, respectively, of FIGURE 1.

The chills of this invention are best described by reference to the accompanying drawings wherein the reference numeral 10 designates the chill .plate portion of substantially uniform thickness having convex face 12 which is curved transversely with respect to the length thereof so as to precisely conform to the radius of curvature of the mold cavity where the chill is to be used. Extending from between the longitudinal edges of face 14, opposite face 12, is elongated cooling fin 16 which will be embedded in the sand core or mold. Fin 16 preferably extends in a substantially radial direction from midway between the longitudinal edges of face 14. Chill plate 10 and cooling fin 16 are each fabricated of a metal having a high heat capacity and conductivity, and these portions are usually fabricated of the same met-a1.

In the preferred embodiment of cooling fin 16, it is formed with a substantially straight longitudinal edge portion 'adjOiHing chill plate 10 and a sinuous longitudinal edge portion remote from chill plate 10, as illustrated, so that it can be securely anchored in the sand. It will be apparent that the extent of the sinuousness of the edge portion of fin 16 remote from plate 10 will depend upon the size of the chill, but cooling fin 16 will be off-set from the radius of plate 10 about 10 degrees at the maximum areas of deflect-ion.

Although the chill is illustrated as having a convex outer face (face 12 of FIGURE 1), it will be apparent that the outer face can be otherwise shaped i.e., either concave or flat, so as to conform with a convex or flat surface of a mold cavity.

I claim:

1. An external chill which comprises an elongated metallic body of substantially uniform thickness presenting a convex outer face which is curved transversely with respect to the length of said body and an elongated metallic fin extending in a substantially radial direction from the center of the face of said body opposite said outer face, said fin having a substantially straight longitudinal edge portion adjacent to said body and a sinuous longitudinal edge portion remote from said body.

2. An external chill which comprises an elongated metallic body of substantially uniform thickness presenting a convex outer face which is curved transversely with respect to the length of said body and an elongated metallic fin extending in a substantially radial direction from the center of the face of said body opposite said outer face, said fin being coextensive with said body and having a straight longitudinal edge portion adjacent to said body and a sinuous longitudinal edge portion remote from said body, said fin being further characterized as being off-set about 10 degrees from the radius of said body at the maximum deflection of said sinuous longitudinal edge portion.

3. In combination with a mold having a cavity for receiving molten metal, a chill fabricated of metal which comprises an elongated body presenting an outer face which is flush with a wall of said cavity and curved transversely with respect to the length of said body and an elongated fin extending from between the longitudinal edges of the face of said body opposite said outer face, said fin having a substantially straight longitudinal edge portion adjacent to said body and a sinuous longitudinal edge portion remote from said body.

4. In combination with a mold having a cavity for receiving molten metal, a chill fabricated of metal which comprises an elongated body of substantially uniform thickness presenting a convex outer face which is flush with a wall of said cavity and curved transversely with respect to the length of said body and an elongated fin extending in a radial direction from the center of the face of said body opposite said outer face, said fin having a substantially straight longitudinal edge portion adjacent to said body and a sinuous longitudinal edge portion remote from said body.

5. In combination with a mold having a cavity for receiving molten metal, a chill fabricated of metal which comprises an elongated body presenting an outer face having a substantially straight longitudinal edge portion adjacent to said body and a sinuous longitudinal edge portion remote from said body.

References Cited by the Examiner UNITED STATES PATENTS I. SPENCER OVERHOLSER, Primary Examiner.

V. K. RISING, Assistant Examiner.

Claims (1)

1. AN EXTERNAL CHILL WHICH COMPRISES AN ELONGATED METALLIC BODY OF SUBSTANTIALLY UNIFORM THICKNESS PRESENTING A CONVEX OUTER FACE WHICH IS CURVED TRANSVERSELY WITH RESPECT TO THE LENGTH OF SAID BODY AND AN ELONGATED METALLIC FIN EXTENDING IN A SUBSTANTIALLY RADIAL DIRECTION FROM THE CENTER OF THE FACE OF SAID BODY OPPOSITE SAID OUTER

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