Tensile Properties and Hardness Distribution on Cross Section of Pb–Less Brass with Groove Rolling

Abstract

Conventional brass rods are added a little lead to improve machinability. However, lead is a toxic heavy metal. So it is expected that lead–less brass rod will be advanced in the future. Following these trends, we need strengthen lead–free brass to obtain the same high strength and excellent machinability as conventional materials.

In this study, we strengthened lead–less brass rods by groove rolling, and examined the microstructure and mechanical properties of them. It is known that rod materials such as extruded materials differ in hardness between the central part and edge part, because of difference in processing degree. So we investigated the effect of groove rolling on hardness distribution on a cross section of lead–less brass rods. It can be expected that groove rolling can be processed until the center compared to the extrusion method.

Lead–less brass had few β’ phases and coarse grains compared with lead added brass. But the grains were refined by groove rolling. Strength increased by grain refinement and work hardening, while elongation was reduced. The difference in hardness between the edge and the center of the groove rolled rods was almost the same as that of the drawn rods.