Material used to combat thermal expansion related defects in the metal casting process
View Patent ↗Thermal expansion defects, i.e. veining, are reduced in iron, steel, and nonferrous castings by adding a lithia-containing material in a sufficient amount to the silica sand mold. Adjusting current formulations to maximize the use of lesser expensive raw materials and minimize the use of more expensive raw materials to lower the overall percentages of lithia/metallic oxide containing additives while still reducing or eliminating thermal expansion related defects in the metal casting process reduces the overall cost to manufacture the product.
1. A material used to combat thermal expansion defects in silica sand foundry molds or cores, said material comprising:
52.75% spodumene;
22.75% black iron oxide;
5.00% red iron oxide; and
19.50% filler material.
2. The material of claim 1 wherein the filler material is ilmenite (FeO—TiO 2 ).
3. A method of making a metal casting from silica sand foundry molds or cores comprising the steps of:
preparing a mixture comprising at least about 80% by weight of silica sand, between about 0.5% to about 10% by weight of a binder, and at least about 3.0% by weight of a material used to combat thermal expansion defects, said material comprising 52.75% spodumene, 22.75% red iron oxide, 5.00% black iron oxide and 19.50% of a filler material;
shaping said mixture to form the sand mold or core having a desired pattern therein; and
pouring molten metal into said pattern, allowing the molten metal to cool and harden, and removing the mold or core to produce a metal casting.
4. The method of claim 3 wherein the filler material is ilmenite (FeO—TiO 2 ).