Loading patent…
AssigneeGM Global Technology Operations LLC
InventorsSuresh Sundarraj, Parag Agarwal, Anil K. Sachdev
Estimating the term…
Residual stress is reduced in light metal alloy articles, e.g. aluminum alloy articles, formed as castings against a sand casting mold body by incorporating a wax composition of suitable softening or melting temperature with the sand particles of the mold or core body. The hot cast metal heats adjoining surfaces of the mold body. As the cooling metal forms a solid shell, the surrounding sand particle and wax mixture are heated sufficiently to melt or soften the wax incorporated on or between sand particles. This softens portions of the rigid mold body that could otherwise restrain shrinking surfaces of the casting and produce unwanted stressed regions that are retained in the casting and must be removed by subsequent processing.
A method of making a sand particle-containing mold body for casting articles of light metal alloys where article-shaping surfaces of the mold body are heated by the cast metal and at least a portion of the surface of the cast article shrinks against an article-shaping surface of the mold body as the cast metal solidifies and cools, the method comprising:
A method of making an article of a light metal alloy by casting a melt of the light metal alloy against an article shape-defining surface of a sand particle-containing mold body where a surface of the cast article shrinks against an article shape-defining surface of the mold body as the cast metal forms an initial solidified shell and then fully solidifies and cools, the method comprising:
A sand mold body having a surface for forming at least a portion of an aluminum alloy casting, the mold body being formed of a mixture comprising sand particles and wax, the composition of the wax and the proportion of wax in the sand particle and wax mixture being predetermined so that the wax softens when the mold body is heated by cast aluminum alloy for the purpose of reducing residual stress in the casting.
Dependencies are inferred from the claim text.