METHOD FOR PRODUCING HIGH-STRENGTH DUPLEX STAINLESS STEEL

摘要

The invention relates to a method for producing a high-strength ferritic austenitic duplex stainless steel having the tensile strength level of at least 1000 MPa and with retained formability with the TRIP (transformation induced plasticity) effect with deformation, characterized in that after the heat treatment on the temperature range of 950-1150°C and cooling the ferritic austenitic duplex stainless steel comprising, wt.%: less than 0.05% carbon (C), 0.2-0.7% silicon (Si), 2-5% manganese (Mn), 19-20.5% chromium (Cr), 0.8-1.5% nickel (Ni), less than 0.6% molybdenum (Mo), less than 1% copper (Cu), 0.16-0.26% nitrogen (N), and one or more added elements: up to 0.5% tungsten (W), up to 0.2% niobium (Nb), up to 0.1% titanium (Ti), up to 0.2% vanadium (V), up to 0.5% cobalt (Co), up to 50 ppm boron (B) and up to 0.04% aluminium (Al), the balance being iron (Fe) and inevitable impurities occurring in stainless steels, is deformed with a reduction degree of at least 10% and then the heat treatment is carried out within the temperature range of 100-450°C for a period of 1 s-20 min. With a reduction degree of 20% the elongation (A₅₀) is at least 15%.