HIGH-STRENGTH HIGH-DUCTILITY TWO-PHASE STAINLESS STEEL AND PROCESS FOR PRODUCING THE SAME

摘要

A high-strength high-ductility two-phase stainless steel comprising at most 0.10 % (by mass, the same will apply hereinbelow) of carbon, at most 2.0 % of silicon, at most 4.0 % of manganese, at most 0.040 % of phosphorus, at most 0.010 % of sulfur, at most 4.0 % of nickel, 10.0-20.0 % of chromium, at most 0.12 % of nitrogen, over 0.0050 to 0.0300 % of carbon, at most 0.02 % of oxygen, at most 4.0 % of copper, and, if necessary, at most 0.02 % of aluminum, at most 3 % of molybdenum, at most 0.20 % of rare earth element(s), at most 0.20 % of yttrium, at most 0.10 % of calcium and at most 0.10 % of magnesium, and the balance consisting of iron and inevitable impurities. This steel has a hardness (HV) of at least 200 and a two-phase structure composed of 20-95 vol. % of a martensitic phase having a mean particle diameter of at most 10 mu m and 80-5 vol. % of a ferritic phase in strip form.