low temperature casting process and the low-temperature casting apparatus of spheroidal graphite cast iron

摘要

PROBLEM TO BE SOLVED: To provide a low temperature casting method and a low temperature casting apparatus for spheroidal graphite cast iron which is obtained by precision casting using a die and has high strength equivalent to that of a forged one and generates no external or internal defect.;SOLUTION: The low temperature casting method includes a vacuum processing step of storing molten metal 12 of spheroidal graphite cast iron subjected to spheroization treatment into a vacuum processing apparatus 2, and keeping the molten metal 12 at the predetermined degree of vacuum for the predetermined time, a pouring step of instantaneously pouring molten metal present in temperature range of 1,350°C to the liquidus temperature and having passed through the vacuum processing step into a die 5, and a pressurizing step of pressurizing the entire cavity C of the die 5 by using a pressurizing apparatus 4 after pouring the molten metal. Since the molten metal of spheroidal graphite cast iron is modified by the vacuum processing, a casting of spheroidal graphite cast iron of fine structure and high strength can be obtained by pressurizing and rapidly cooling the molten metal of cast iron present at the low-temperature range including the semi-solidification temperature range in the die.;COPYRIGHT: (C)2012,JPO&INPIT