Abstract

The Fe-15%Cr-15%Ní austenitic stainless steel has a fully austenitic microstructure, which is free of 5-ferrite and intermetallic phases. The formation of strain-induced martensite is also not observed. The effect of niobium additions in Fe-15%Cr-15%Ni stainless steel microstructure was studied. Additions of 0.5, 1.0, and 2.0 wt.% of niobium were done in the stainless steel studied. The as-cast microstructure of the studied steels was characterized and analyzed by using several techniques. In the as-cast steels samples, the results show absence of magnetism. The results also show the niobium addition caused an enlargement of the solidification interval and propitiates Laves phase formation. The Laves phase is hard and fragile and its formation between austenite dendrites causes loss of toughness. The mechanical test done made it possible to observe crack propagation alongside the fragile Laves phase