Pressure die-casting method and products obtained thereby

摘要

After a cavity 2 of a die-casting mold 1 is evacuated to exclude gases, oxygen gas is blown into the cavity 2 until an internal pressure of the cavity exceeds the atmospheric pressure, and then a molten metal 5 is forcibly injected into the cavity 2. The cavity 2 is evacuated to a degree of vacuum less than 100 millibar through a suction nozzle 11. The oxygen gas is blown through a nozzle 14 into the cavity 2 so as to fill the cavity 2 with the oxygen gas at an internal pressure higher than the atmospheric pressure. When the molten metal 5 is injected into the cavity 2 clarified in this way, inclusion of gases is perfectly prohibited. As a result, obtained die-cast products are free from defects such as blowholes or porosity caused by inclusion of gases and so useful as functional members as well as structural members.