ASTM B981/B981M, Specification for Low Leaded Brass Rod, Bar and Shapes, was developed by Subcommittee B05.02 on Rod, Bar, Wire, Shapes and Forgings, part of ASTM International Committee B05 on Copper and Copper Alloys.
“Since 1997, there have been increasing legislation, regulation and voluntary standards requirements controlling lead content and lead leachate in potable water fittings and fixtures,” Larry Muller, manager, metallurgy and technical services, Chase Brass and Copper Co, and a B05 member, explained. “Companies producing these products have often seen the traditional extruded and drawn leaded machining brasses that contain greater than 2.5% lead disqualified either because of leachate performance or lead content.”
As a result, Muller notes, some manufacturers have changed alloys used for machined components to existing brass alloys with lower lead content. While these alloys were already in ASTM standards, the standards were for forging, not machining.
“Since mechanical properties of extruded and drawn rod change when you heat and forge, there are no properties in the existing standards for the input rod,” Muller stated. “Mechanical properties such as tensile, elongation and yield strength ranges are needed for understanding the way the material will perform under machining conditions with the redesign of parts using these different lower leaded alloys.”
Muller says that statistical analysis was performed on production properties for alloys C36300, C36500, C37000, C37100 and C37700 to develop the minimum tensile strength, yield strength and elongation as a function of diameter that are included in B981/B981M.