DUPLEX STAINLESS STEEL

摘要

The invention relates to a duplex stainless steel composition consisting, in percent by weight, of: C < 0.05%; 21% = Cr < 25%; 1% = Ni = 2.95%; 0.16% = N = 0.28%; Mn = 2.0% Mo +W/2 = 0.50%; Mo = 0.45%; W < 0.15%; Si < 1.4%; Al < 0.05%; 0.11% = Cu = 0.50%; S < 0.010%; P = 0.040%; Co = 0.5%; REM = 0.1%; V = 0.5%; Ti = 0, 1%; Nb = 0.3%; Mg < 0.1%, the balance being iron and impurities resulting from the smelting, and the microstructure consisting of austenite and 35 to 65% ferrite by volume, the composition furthermore satisfying the following relationships: 40 = IF < 70 with IF = 6´(%Cr + 1.32´%Mo + 1.27´%Si) - 10´(%Ni + 24´%C + 16.15´%N + 0.5´%Cu + 0.4´%Mn) - 6.17 and IRCL > 30.5, where IRCL = %Cr +3.3´%Mo +16´%N + 2.6´%Ni - 0.7´%Mn, and to a process for manufacturing plates, sheets, coils, bars, wires, sections, forgings and castings made of this steel.