Aluminum-Alloy Sand Castings

B26/B26M: Standard Specification for Aluminum-Alloy Sand Castings

For engineers and designers seeking reliable aluminum alloy sand castings, ASTM's B26/B26M standard is an essential guide. This industry-leading specification provides a comprehensive framework for ensuring the quality, composition, and mechanical properties of these widely used components, underpinning the integrity of countless manufactured goods across diverse sectors.

What is B26/B26M?

ASTM B26/B26M is the authoritative standard for specifying aluminum-alloy sand castings. Originating from early 20th-century material standards, it has evolved into a comprehensive document detailing requirements for general-purpose aluminum alloy sand castings, ensuring consistency and performance in a wide array of applications.

Scope & Purpose

This standard governs the composition, mechanical properties, and quality control for aluminum-alloy sand castings intended for general applications. Its scope specifically defines acceptable aluminum alloys and their tempers for sand casting processes, along with requirements for chemical composition and mechanical testing. It explicitly excludes highly loaded or safety-critical applications, which may necessitate more stringent specifications.

Who Must Comply?

• • Primary audience: Materials Engineers, Metallurgists, Design Engineers, Quality Inspectors, and Foundry Operators.
• • Industries affected: Aerospace, Automotive, Industrial Machinery, General Manufacturing, and Defense sectors.
• • Compliance nature: Primarily voluntary, but often mandated by contractual agreements, purchase orders, and specific industry requirements.
• • Enforcement: Typically verified by purchasers, quality assurance departments, and third-party inspectors during material qualification and production oversight.

Key Requirements Overview

Professionals working with B26/B26M must adhere to several core provisions:

• • The standard requires that aluminum alloy sand castings conform to specified chemical composition limits, verified through approved analytical methods.
• • Key provisions include the establishment and verification of mechanical properties, such as tensile strength and elongation, for designated alloys and tempers.
• • Foundry operators must ensure adherence to manufacturing practices that promote consistent casting quality and dimensional accuracy.
• • The specification mandates specific sampling and testing procedures to confirm conformance to the standard's requirements.
• • Provisions are made for various inspection methods, including visual, liquid penetrant, and radiographic examination, to assess casting integrity.

Related Standards & References

ASTM B26/B26M is often used in conjunction with other ASTM standards to ensure a complete engineering solution. For instance, Specification B179 provides guidance on aluminum alloys in ingot and molten forms for all casting processes, serving as a precursor for the raw material. Test Methods B557/B557M are crucial for performing the tensile testing required to verify mechanical properties. Additionally, Practice E155 offers valuable reference radiographs for inspecting aluminum castings, complementing the visual and NDT requirements outlined within B26/B26M.