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Zinc-Aluminum Alloys
ZA-8, ZA-12, and ZA-27 are zinc-aluminum (ZA) die casting alloys with increasing aluminum content (approximately 8%, 12%, and 27% respectively), offering superior strength, hardness, and creep resistance compared to traditional Zamak zinc alloys.
Key differences:
Casting Process: ZA-8 is the only one suitable for hot-chamber die casting (faster and more cost-effective due to lower melting point), while ZA-12 and ZA-27 require cold-chamber die casting (higher temperatures and more careful process control).
Mechanical Properties: Strength and hardness increase with aluminum content. ZA-27 provides the highest tensile strength, hardness, and wear resistance (often competing with bronze or aluminum), making it ideal for high-load applications. ZA-12 offers a balanced intermediate performance with good bearing properties and dimensional stability. ZA-8 has the best creep resistance among hot-chamber zinc alloys but lower overall strength than the others.
Density and Weight: ZA-27 is the lightest (lowest density), followed by ZA-12, then ZA-8.
Finishing: ZA-8 and ZA-12 can be easily chrome-plated; ZA-27 is generally not recommended for plating.
Castability and Applications: ZA-8 excels in thin-wall sections and high-production hot-chamber runs. ZA-12 has better overall castability than ZA-27 and is versatile for bearing or structural parts. ZA-27, while strongest, has poorer castability and is used where maximum performance justifies the challenges.
ZA die casting alloys represent a new family of zinc-based die casting metal materials that contain higher aluminum content than standard zinc
alloys. These die casting 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 (zamak). ZA-8 is recommended for hot chamber die casting. 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 Die Casting Alloy
ZA-8 -- Provides strength, hardness and creep properties
ZA-12 Die Casting Alloy
ZA-12 -- Provides excellent bearing properties with strength and hardness characteristics between ZA-8 and ZA-27. Good
dimensional stability properties and somewhat better castability than ZA-27.
ZA-27 Die Casting Alloy
ZA-27 -- Offers the highest mechanical properties of the ZA family and is therefore recommended when maximum performance is
required.
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