US Patent 11932926 Duplex ferritic austenitic stainless steel composition

A duplex ferritic austenitic stainless steel having high formability utilizing the TRIP effect and high corrosion resistance with the high pitting resistance equivalent. The duplex stainless steel contains less than 0.04 weight % carbon, 0.2-0.8 weight % silicon, 0.3-2.0 weight % manganese, 14.0-19.0 weight % chromium, 2.0-5.0 weight % nickel, 4.0-7.0 weight % molybdenum, less than 4.5 weight % tungsten, 0.1-1.5 weight % copper, 0.14-0.23 weight % nitrogen, the rest being iron and inevitable impurities occurring in stainless steels. Further, the co-effect of the chromium, molybdenum and tungsten contents in weight % is in the range of 20<(Cr+Mo+0.5W)<23.5, where the ratio Cr/(Mo+0.5W) is in the range of 2-4.75.