Low pressure die casting for non-ferrous metals - applying vacuum followed by finishing pressure

摘要

In a low-pressure die casting process, esp. for nonferrous metals, the cavities of the mould are first evacuated, pref. to a pressure of 0.1-0.9 atmos below atmospheric pressure. The molten metal is then pressed at a slow flow rate in the mould, followed by a finishing pressure of 2-10 bar (5-6 bar) applied to the molten metal in the riser. This allows even thick-walled castings of great density and complex configuration to be cast free from air or gas inclusions. It requires little equipment and produces nonferrous alloys of high purity which can be heat treated.