Casting sand cores and expansion control methods therefor

摘要

Thermal expansion of sand cores and the formation of vein defects during metal casting operations can be substantially eliminated, with substantially reduced costs, by using an anti-veining material comprising less than about 4% by weight of a lithia-containing material, and at least about 1% by weight of ferric oxide (Fe₂O₃), said anti-veining material preferably comprising 2.5% LiO, 10-25% of TiO₂, 15-25% Al₂O₃, 10-25% of Fe₃O₄, and 60-70% of SiO₂ mixed with about 1% by weight of Fe₂O₃, preferably red iron oxide.