Free-Cutting Brass Rod, Bar and Shapes for Use in Screw Machines

B16/B16M: Standard Specification for Free-Cutting Brass Rod, Bar and Shapes for Use in Screw Machines

For engineers and manufacturers striving for efficiency and reliability in high-speed machining operations, understanding and adhering to material standards is paramount. ASTM B16/B16M provides an essential framework for specifying and procuring free-cutting brass, a material vital for producing intricate components with precision and speed. This industry-leading standard ensures that the brass rod, bar, and shapes meet stringent requirements for machinability, making it a proven choice for demanding applications.

What is B16/B16M?

ASTM B16/B16M is the authoritative standard specification that defines the requirements for free-cutting brass rod, bar, wire, and shapes intended for high-speed screw machining and moderate thread rolling. Originating from ASTM International, this standard ensures material consistency and performance for specific copper alloy compositions, primarily UNS C36000 and C36010. Its primary purpose is to establish a reliable benchmark for materials used in automated machining processes where material quality directly impacts production rates and finished part integrity.

Scope & Purpose

This standard governs the properties, composition, and dimensional tolerances of wrought copper alloy products designed for applications demanding excellent machinability. Specifically, it covers free-cutting brass in the form of rod, bar, wire, and various shapes produced from Copper Alloy UNS Nos. C36000 or C36010. The specification is particularly relevant for components manufactured using automatic screw machines and processes involving moderate thread rolling. It does not, however, cover general requirements for other copper alloy forms, nor does it address the specific design of the screw machines themselves or the cutting tools used.

Who Must Comply?

• • Primary audience: Materials Engineers, Manufacturing Engineers, Quality Control Inspectors, Production Managers, and Machine Operators.
• • Industries affected: Metalworking, Automotive Manufacturing, Aerospace Manufacturing, Industrial Equipment Manufacturing, Fastener Manufacturing, and any sector utilizing precision machining of brass components.
• • Compliance nature: Voluntary, but adoption is highly recommended for ensuring product quality, interchangeability, and meeting customer specifications. Many purchasing agreements will mandate compliance.
• • Enforcement: Typically enforced through contractual agreements, customer audits, and internal quality assurance processes. Material suppliers are responsible for ensuring their products meet the standard's requirements, and purchasers verify this through certifications and testing.

Key Requirements Overview

The standard requires that free-cutting brass products conform to specific chemical composition limits, primarily focusing on copper, lead, iron, and zinc content to enhance machinability. Professionals must ensure that the material is supplied in designated tempers (e.g., O60, H02, H04) that are suitable for machining operations, with specific mechanical properties like tensile and yield strength, and elongation, defined for various product sizes and forms. Key provisions include detailed tables for chemical composition and mechanical properties, as well as guidelines for permissible dimensional variations for rod, bar, and shapes. The standard also references general requirements for wrought copper and copper alloys, ensuring a comprehensive approach to material quality.

Related Standards & References

ASTM B16/B16M works in conjunction with other ASTM standards to provide a complete material specification. Complementary standards include ASTM B249/B249M,