Decompression die-cast casting manner and die null for decompression die-cast casting

摘要

PURPOSE: To provide a casting method, by which powdery releasing agent can uniformly be applied, in the reduced pressure die casting method using the powdery releasing agent. ;CONSTITUTION: A cavity 3 is formed with a fixed die 1 and a movable die 2, and plural gates 21 communicating with the cavity 3 are arranged. The pressure in the cavity 3 is reduced and the powdery releasing agent 9 is supplied into the cavity 3 through the gates 21 and further, the molten metal is injected into the cavity 3 through the gates 21 and solidified. At the time of using lT for the whole peripheral length of the cavity 3 on the parting surface 20 and lG for the peripheral length at the part of the gate communicating zone from the gate 21 at the end part to the gate 21 of the other side farthest part in the peripheral length on the parting surface 20, the gates 21 are formed so as to become lG/iT≥0.3.;COPYRIGHT: (C)1996,JPO