Choosing the Right Metal for Die Casting

Die casting is valuable in many industries for cost effectiveness in large-scale production, with short fabrication times per part and little to no need for machining afterward. Components made by die casting are found in automobiles, medical equipment, toys, heavy machinery, decorations and more. A variety of non-ferrous metals can be die cast, and choosing one appropriate to the product’s specifications is important.

Common Die Casting Metals

Die casting employs a range of non-ferrous metals and alloys, with specific compositions graded for optimal casting. Zinc and aluminum die castings are especially common, as they cast easily due to low melting temperatures and their alloys possess high strength. Conversely, copper alloys see use when corrosion and wear resistance are most important; tin and lead alloys, while less common, are similarly useful here. Magnesium, like aluminum, has a high strength-to-weight ratio, and magnesium alloys are used when parts must be as lightweight as possible.

Picking Alloys for Casting

The alloys most commonly used for die casting have various trade-offs in physical and mechanical properties, ease of fabrication and economic efficiency. There is no “one size fits all” casting metal. Selecting the ideal alloy, then, requires an assessment of what properties are most important for your product and fabrication process. Major factors include:

  • structural properties such as strength-to-weight ratio and dimensional tolerances, including how these vary based on temperature
  • impact strength and resistance to deformation or fracture
  • surface finish quality, both at fabrication and over time
  • corrosion and abrasion resistance
  • ease of machining
  • alloy cost and cost of casting, based on precision, necessary machining and the wear inflicted on die steels during production

Data on die casting alloys, including how properties differ as the composition changes, are frequently made available via engineering and industry standards. To best match an alloy to a particular project, it’s best to consult with experts in metallurgy and die casting, whether in-house or via manufacturing partners.