The website eFunda defines die-cast as the result of a moulding process that involves injecting metal into a mold at pressures of 1,450 to 30,500 psi. The pressure creates a part that is uniform in size, closely matching the mold and requires little to no post-machining work.
The molds used to create die-cast parts or models are made from hardened steel. This steel makes the molds usable for casting parts using a variety of metals and alloys, including aluminum, aluminum alloys, copper alloys, magnesium and zinc. Iron and steel, however, are two materials that cannot be used in the die-casting process.