Hardness and tensile behaviour of friction stir welded Cu-40wt%Zn brass

Abstract

Modern industry requires not only a high quality production and fabrication systems but also a green manufacturing system. The conventional welding processes could not fulfill these requirements, which in turn lead to special welding processes. In conventional welding process it is difficult to weld brass because of high thermal conductivity and zinc evaporation. These problems can be overcome by new solid state welding process technique namely friction stir welding (FSW). The main objective of the study is to analyze the joining behaviour of 6 mm thick Cu-40%Zn brass plates. The tool rotational speed, traverse speed, microstructure analysis, hardness profile and scanning electron microscopy (SEM) analysis were carried out. In this case, the weld joint made in brass-brass weld resulted joint efficiency of 58%. The weld nugget shows that the hardness profile of brass-brass weld hardness was almost same as base metal hardness. The weld nugget is very fine with even grain size in the principal axis directions and it is of 8-10 µm and 4-6 µm in α and β, respectively. The fractograph shows some fine dimples in the fractured surface indicating the ductility.