Zinc and Zinc-Aluminum (ZA) Alloys in Ingot Form for Foundry and Die Castings

B240: Standard Specification for Zinc and Zinc-Aluminum (ZA) Alloys in Ingot Form for Foundry and Die Castings

For engineers and designers working with nonferrous metals, ensuring the integrity and performance of cast components begins with the foundational materials. ASTM B240 provides an authoritative framework for the procurement of high-quality zinc and zinc-aluminum (ZA) alloy ingots, serving as an essential guide for reliable casting operations. This comprehensive standard is the cornerstone for professionals seeking to specify and source ingots that meet stringent industry requirements for both foundry and die casting applications.

What is B240?

ASTM B240, "Standard Specification for Zinc and Zinc-Aluminum (ZA) Alloys in Ingot Form for Foundry and Die Castings," is an industry-leading document that establishes the requirements for various zinc and ZA alloy compositions supplied in ingot form. Developed by ASTM International, this standard ensures that the raw material used for manufacturing castings possesses the necessary chemical composition and quality attributes for successful remelting and casting processes. Its primary purpose is to facilitate consistent, predictable outcomes in the production of zinc and ZA alloy castings.

Scope & Purpose

The scope of ASTM B240 is focused on defining the characteristics of zinc and zinc-aluminum alloy ingots intended for remelting in pressure die casting and foundry casting operations. It specifies seven distinct alloy compositions, detailing their chemical composition limits. The standard also touches upon ingot sizes and shapes, and references necessary sampling and analytical procedures. While it governs the ingot material, it does not cover the final casting specifications, which are addressed by separate standards.

Who Must Comply?

• • Primary audience: Materials Engineers, Metallurgists, Foundry Operators, Casting Process Engineers, and Quality Control Inspectors.
• • Industries affected: Automotive, Aerospace, Electronics, Hardware Manufacturing, and Consumer Goods.
• • Compliance nature: Voluntary, but widely adopted and often specified in purchasing contracts and procurement documents.
• • Enforcement: Typically enforced through contractual agreements between suppliers and purchasers, and validated by internal quality assurance programs and third-party testing.

Key Requirements Overview

The standard requires that zinc and ZA alloy ingots conform to specific chemical composition limits for key elements such as aluminum, magnesium, copper, iron, lead, cadmium, and tin, as detailed in its tables. Professionals must ensure that the ingots are free from dross, foreign matter, and excessive surface oxidation to prevent casting defects. Key provisions include the designation of seven distinct alloy types, each with unique properties suitable for different casting applications. The standard also mandates that chemical analysis be performed using approved methods to verify conformance.

Related Standards & References

ASTM B240 works in conjunction with other critical ASTM standards. Specification B86 ("Standard Specification for Zinc and Zinc-Aluminum (ZA) Alloy Foundry and Die Castings") is a complementary standard that specifies the requirements for the final castings produced from ingots conforming to B240. Practice B275 ("Practice for Codification of Certain Nonferrous Metals and Alloys, Cast and Wrought") provides guidance on alloy designations, while Test Methods E536 outlines the procedures for chemical analysis of zinc and zinc alloys, ensuring accurate verification of material composition.