Zinc alloys (Table 2) are the easiest to die cast. Ductility is high and impact strength is excellent, making these alloys suitable for a wide range of products. Zinc alloys can be cast with thin walls and excellent surface smoothness making preparation for plating and painting relatively easy.
It is essential that only high purity (99.99 + 0/0) zinc metal be used in the formulation of alloys. Low limits on lead, tin and cadmium ensure the long-term integrity of the alloy’s strength and dimensional stability.
ZA alloys represent a new family of zinc based die casting materials which contain higher aluminum content than standard zinc alloys. These alloys provide high strength characteristics plus high hardness and good bearing properties (Table 2). Thin wall castability characteristics and die life are similar to zinc alloys. ZA-8 is recommended for hot chamber die casting, which ZA-12 and ZA-27 must be cast by the cold chamber die casting process. All ZA alloys offer similar creep properties and are superior to standard zinc alloys.
ZA-8 — Provides strength, hardness and creep properties.
ZA-12 — Provides excellent bearing properties with strength and hardness characteristics between ZA-8 and ZA-27, plus good dimensional stability properties and somewhat better castability than ZA-27.
ZA-27 — Offers the highest mechanical properties of the ZA family and is, therefore, recommended when maximum performance is required.