Development of Pb-Free Austenitic Stainless Steels

Abstract

Pb-free austenitic stainless steels were investigated by adding sulfur, rare earth (Re) elements and bismuth. The metallurgical properties, machinability and mechanical properties of both steels were examined. The results show that a significant amount of grey, spindle shaped inclusions were discovered in austenitic stainless steels, and they should belong to MnS inclusions containing bismuth element and rare earths oxide. The addition of S, Bi and Re to austenitic stainless steels improved the machinability. The machinability of steel B is better than that of steel A in a way. The mechanical properties of steel B are better than those of steel A, especially total elongation owing to the presence of rare earth elements. From the viewpoint of life cycle assessment, it is proposed that the development of Pb-free austenitic stainless steels containing S, Bi and Re is desirable.