Stainless steel, method for manufacturing of stress cracking free workpieces and product made thereof

摘要

Stainless steel having a structure with at least 15 vol.% ferrite and a balance of austenite contains alloying additions of chromium and manganese, and optionally nickel, silicon, molybdenum, aluminum and copper. Stainless steel having a structure with at least 15 vol.% ferrite and a balance of austenite comprises (in wt.%): 0.02-0.08 carbon (C), 0.1-0.5 nitrogen (N), 16.0-20.0 chromium (Cr), 6.0-12.0 manganese (Mn), at most 9.05 nickel (Ni), at most 3.0 silicon (Si), at most 3.0 molybdenum (Mo), at most 2.0 aluminum (Al), at most 3.0 copper (Cu) and a balance of iron (Fe) and impurities (where 1.3 less than t less than 1.8 and t = (%Cr + 2%Mo + 1.5%Si + 3%Al -5)/(0.3%Mn + %Ni + 0.5%Cu + 15(%C + %N) +2)). Md30 temperature of the austenitic phase is not more than -55degrees C (where Md30 (degrees C) = 413 - 462(%C + %N) - 9.2%Si - 8.1%Mn - 13.7%Cr - 9.5(%Ni + %Cu) - 18.5%Mo). An Independent claim is also included for a process for the production of crack-free molded parts made from the above stainless steel. Preferred Features: The stainless steel structure comprises not more than 40 vol.% ferrite.