Patent ID: 7343959

Claim:
A pressure casting method of a magnesium alloy comprising the steps of: cooling a molten magnesium alloy to a temperature at which a solid phase and a liquid phase coexist to form a partially molten state containing a solid-phase; further cooling the partially molten state below a solidus line temperature to form a solid-phase granularly crystallized solid material, in which a ratio of primary crystals of said solid material is 55 to 65%; partially-melting the solid material in a molding machine provided with heating means to a semi-solid body having thixotropic properties in a state in which a solid-phase and a liquid-phase coexist, so that the semi-solid has the size of a main solid phase of 50 to 250 μm and a solid-phase ratio of 30 to 70%; and pressure casting the semi-solid into a mold through a nozzle having a diameter of 8 to 15 mm and a gate while maintaining the semi-solid state, to mold a metal product having a ratio of primary crystals of 20 to 50%.