Abstract
Sand molds were frozen by liquid nitrogen contained in a copper box. Freezing rate of the molds increased either as the moisture content increased, the mold density increased or the molding sand became coarser. The consumption rate of liquid nitrogen for freezing silica sand molds corresponded to the freezing rate of the molds. Freezing rate of various sand molds increased in the order of chamotte sand, chromite sand, olivine sand, zircon sand and silica sand. Consumption ratio of liquid nitrogen per unit volume of frozen mold increased in the order of silica sand, chamotte sand, olivine sand, chromite sand and zircon sand. Thus silica sand is the most economical aggregate to be frozen among the sands studied.
