Zinc and Zinc-Aluminum (ZA) Alloy Foundry and Die Castings

ASTM B86: Standard Specification for Zinc and Zinc-Aluminum (ZA) Alloy Foundry and Die Castings

For engineers and designers working with nonferrous metals, understanding material specifications is paramount to achieving successful product development. ASTM B86, the Standard Specification for Zinc and Zinc-Aluminum (ZA) Alloy Foundry and Die Castings, stands as an essential document, providing the comprehensive framework for specifying and procuring these versatile casting alloys. This industry-leading standard ensures consistency, quality, and performance in a wide range of manufactured components.

What is ASTM B86?

ASTM B86 is an authoritative standard published by ASTM International that defines the chemical composition, material properties, and acceptable forms for zinc and zinc-aluminum (ZA) alloy castings. It originates from decades of industry experience and serves as the proven benchmark for ensuring these alloys meet the rigorous demands of various manufacturing processes and applications. Its primary purpose is to facilitate clear communication and contractual agreement between suppliers and users of zinc and ZA alloy castings.

Scope & Purpose

This standard governs the specification of seven distinct alloy compositions, including traditional Zamak alloys and ZA alloys. It covers materials intended for both foundry casting (gravity or low-pressure pouring into molds) and pressure die casting applications. Furthermore, ASTM B86 encompasses continuous cast bar stock produced from these alloys, which is valuable for prototyping and machining operations. The scope does not extend to the manufacturing processes themselves but rather to the material requirements of the final cast product and bar stock.

Who Must Comply?

• • Primary audience: Materials Engineers, Metallurgists, Foundry Engineers, Casting Designers, Quality Control Inspectors, and Manufacturing Engineers.
• • Industries affected: Manufacturing, Automotive, Aerospace, Electronics, Hardware, Consumer Products, and any sector utilizing intricate metal components.
• • Compliance nature: Voluntary, but adoption is highly recommended and often contractually mandated by purchasers seeking reliable material performance.
• • Enforcement: Typically enforced through purchase orders, supplier audits, and certification of conformance by manufacturers.

Key Requirements Overview

ASTM B86 outlines several core requirements for zinc and ZA alloy castings:

• • The standard mandates specific chemical compositions for each of the seven covered alloys, defining permissible ranges for primary elements and maximum limits for impurities.
• • It requires that castings meet the specified chemical compositions, often verified through sampling and spectrographic analysis.
• • Provision is made for ordering specific alloys and for the inclusion of detailed drawings to define casting dimensions and tolerances.
• • The standard references established testing methods for verifying material properties where applicable.
• • It also addresses nomenclature, ensuring consistent identification of alloys through traditional and UNS designations.

Related Standards & References

ASTM B86 is part of a larger ecosystem of material standards. It frequently references ASTM B240, which covers zinc and ZA alloy ingots used in their production, ensuring a traceable lineage. For broader material characterization, ASTM E8 (Tension Testing of Metallic Materials) and ASTM E23 (Notched Bar Impact Testing of Metallic Materials) may be employed to assess mechanical performance. Additionally, ASTM B949 provides general requirements applicable to zinc and zinc alloy products, offering a complementary layer of specification.