Patent ID: 9212412
Filing Date: 2015-12-15
Classification: C21D,C22C

Abstract:
1. A lean duplex stainless steel having corrosion resistance and toughness of a weld heat affected zone comprising, by mass %, C: 0.06% or less, Si: 0.1 to 1.5%, Mn: 2.0 to 4.0%, P: 0.05% or less, S: 0.005% or less, Cr: 19.0 to 23.0%, Ni: 1.0 to 4.0%, Mo: 1.0% or less, Cu: 0.1 to 3.0%, V: 0.05 to 0.5%, Al: 0.003 to 0.050%, O: 0.007% or less, N: 0.10 to 0.25%, and Ti: 0.05% or less, and having a balance of Fe and unavoidable impurities, wherein an Md30 value expressed by formula <1> is 80 or less, an Ni-bal expressed by formula <2> is −7.1 to −4, the Ni-bal and the N content satisfy formula <3>, the lean duplex stainless steel has an austenite phase area percentage of 40 to 70%, and the lean duplex stainless steel has a value of 2×Ni+Cu of 3.5 or more: wherein, in the above formulas, the element symbols represent the content of the elements in mass %.