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

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

For engineers and designers seeking reliable material solutions for demanding applications, understanding ASTM B86 is essential. This industry-leading standard provides the comprehensive framework for specifying and procuring high-quality zinc and zinc-aluminum (ZA) alloy castings, ensuring performance and consistency in a wide range of manufactured components.

What is B86?

ASTM B86 is the authoritative standard specification for zinc and zinc-aluminum (ZA) alloy foundry castings, die castings, and continuous cast bar stock. Originating from ASTM Committee B02 on Nonferrous Metals and Alloys, its primary purpose is to define the chemical composition requirements and ensure the quality of these widely used casting alloys.

Scope & Purpose

This standard governs the production and acceptance of seven distinct alloy compositions, including traditional Zamak alloys (Alloys 3, 7, 5, and 2) and ZA alloys (ZA-8, ZA-12, and ZA-27). It specifies requirements for both foundry castings (produced via gravity casting) and pressure die castings. While it covers continuous cast bar stock for prototyping and machining, it does not address the broader aspects of casting design or specific performance testing beyond chemical composition.

Who Must Comply?

• • Primary audience: Materials Engineers, Metallurgists, Casting Designers, Foundry Supervisors, and Quality Control Inspectors.
• • Industries affected: Manufacturing, Automotive, Aerospace, Electronics, Hardware, and any sector utilizing zinc or ZA alloy components.
• • Compliance nature: Voluntary, but adoption is highly recommended for ensuring product quality, consistency, and market acceptance.
• • Enforcement: Typically enforced through contractual agreements between suppliers and purchasers, and by internal quality assurance programs.

Key Requirements Overview

• • The standard requires adherence to specific chemical composition limits for various elements, including aluminum, magnesium, copper, iron, lead, cadmium, and tin, to ensure alloy integrity.
• • Professionals must ensure that castings are produced from alloys conforming to the designated compositions, as detailed in the specification's tables.
• • Key provisions include the designation of seven distinct alloy types, each with specific chemical ranges, facilitating precise material selection.
• • The standard outlines the nomenclature used for identifying these zinc and ZA alloys, aligning with recognized industry systems like UNS.
• • It also references essential testing methods and practices for sampling and chemical analysis to verify compliance.

Related Standards & References

ASTM B86 is often used in conjunction with other ASTM standards to provide a complete specification for casting processes and materials. Complementary standards include:

• • ASTM B240: Specification for Zinc and Zinc-Aluminum (ZA) Alloys in Ingot Form for Foundry and Die Castings. This standard complements B86 by defining the requirements for the raw material used to produce the castings.
• • ASTM B949: Specification for General Requirements for Zinc and Zinc Alloy Products. This standard provides overarching requirements applicable to various zinc alloy products, including castings.
• • ASTM E8 / E23: Test Methods for Tension Testing of Metallic Materials and Notched Bar Impact Testing, respectively, which may be referenced for evaluating the mechanical properties of the cast components.