Cast stainless steel for generator water pump impeller - contains carbon, silicon, manganese, chromium, nickel, molybdenum, and vanadium, and pref. also niobium, zirconium, and hafnium

摘要

The stainless cast steel consists of (by wt.) C 0.01-0.15%, Si 0.1-1%, Mn 0.1-2%, Cr 10-15%, Ni 2-7%, Mo 0.1-3%, V 0.05-0.5%, pref. together with =1 of Nb, Zr, and Hf in an amt. 0.005-0.5%, remainder Fe and unavoidable impurities. The cast steels has a mixed structure of martensite and retained austenite. The retained austenite amt. is 10-40%, and the -ferrite amt. is =10%. The as-cast stainless cast steel is heat treated by e.g. normalising at 900-1100 degrees C, cooling for hardening and tempering at 500-650 degrees C. The steel has the excellent strength, toughness and weldability.