Tungsten Base, High-Density Metal

B777: Standard Specification for Tungsten Base, High-Density Metal

For engineers and designers demanding exceptional density, strength, and stability in critical applications, understanding ASTM B777 is essential. This authoritative standard provides a comprehensive framework for specifying and procuring tungsten base, high-density metals, ensuring material performance in challenging environments.

What is B777?

ASTM B777 is the industry-leading standard specification detailing the requirements for machinable, high-density tungsten base metals. Originating from ASTM International's commitment to material excellence, its primary purpose is to define the properties and quality control measures for these specialized alloys, produced through powder metallurgy techniques.

Scope & Purpose

This comprehensive standard governs the composition, physical properties, mechanical properties, and quality assurance for four distinct classes of tungsten base, high-density metal. It is intended for bare or coated parts used in applications requiring high mass in a compact volume, such as aerospace components or radiation shielding. The standard outlines requirements for material production, testing, and inspection, but it does not extend to the design or application of finished parts, nor does it mandate specific coating processes.

Who Must Comply?

• • Primary audience: Materials Engineers, Design Engineers, Quality Control Inspectors, Manufacturing Engineers, and Metallurgists.
• • Industries affected: Aerospace, Defense, Industrial Manufacturing, Medical Device Manufacturing, and Scientific Instrumentation.
• • Compliance nature: Voluntary, but often specified by purchase orders and contracts, making it de facto mandatory for specific procurements.
• • Enforcement: Manufacturers are responsible for ensuring compliance, with purchasers verifying adherence through inspection and testing, often guided by the quality assurance provisions within the standard.

Key Requirements Overview

The standard requires that tungsten base metals be produced from carefully controlled powder mixtures, primarily tungsten with a metallic binder. Professionals must ensure that the material conforms to one of the four specified classes, each with defined nominal tungsten content, density ranges, and hardness limits. Key provisions include stringent testing for mechanical properties such as tensile strength and elongation, as well as verification of microstructure and density through established test methods. Machinability requirements, if specified, must also be met through defined testing protocols.

Related Standards & References

ASTM B777 works in conjunction with other vital ASTM standards. For instance, Test Method B311 is referenced for accurately determining the density of powder metallurgy materials, a critical parameter for these high-density alloys. Test Methods E8 provides the framework for tensile testing, essential for verifying the mechanical integrity outlined in B777. Furthermore, Test Methods E18 is crucial for hardness testing, ensuring material properties meet specified Rockwell C limits for various classes.