The primary metals used in die casting include zinc, copper, aluminum, magnesium, lead, tin, and lead-tin alloys; although die casting iron is rare, it is technically feasible. Specialized die-casting metals include ZAMAK, aluminum-zinc alloys, and specific standards established by the Aluminum Association: AA380, AA384, AA386, AA390, and AZ91D magnesium. The characteristics of these various metals during the die-casting process are as follows:
Zinc: The easiest metal to die cast; it is economical for manufacturing small components, readily accepts surface plating, possesses high compressive strength and ductility, and offers a long die life.
Aluminum: Lightweight; exhibits high dimensional stability when producing complex and thin-walled castings; features strong corrosion resistance, excellent mechanical properties, and high thermal and electrical conductivity; and retains high strength even at elevated temperatures.
Magnesium: Easily machined; possesses a high strength-to-weight ratio; and is the lightest among the commonly used die-casting metals.
Copper: High hardness and strong corrosion resistance; offers the best mechanical properties among common die-casting metals; highly wear-resistant; and possesses a tensile strength comparable to that of steel.
Lead and Tin: High density and exceptional dimensional accuracy; suitable for use in specialized corrosion-resistant components. However, due to public health considerations, these alloys cannot be used in food processing or storage equipment. Alloys of lead, tin, and antimony (sometimes containing a small amount of copper) are used to manufacture manual type characters for letterpress printing as well as for hot stamping applications.
The maximum weight limits for die castings produced using aluminum, copper, magnesium, and zinc are 70 pounds (32 kg), 10 pounds (4.5 kg), 44 pounds (20 kg), and 75 pounds (34 kg), respectively.
