摘要 |
A ferritic-austenitic two-phase stainless steel consisting essentially of, in wt. %, over 0% to not more than 0.05% of C, 0.1 to 2.0% of Si, 0.1 to 2.0 of Mn, 20.0 to 23.0% of Cr, 3.0 to 3.9% of Ni, 0.5 to 1.4% of Mo, over 0% to not more than 2.0% of Cu and 0.05 to 0.2% of N, the steel further containing, when desired, at least one element selected from the group consisting of over 0% to not more than 0.5% of Ti, over 0% to not more than 0.5% of Nb, over 0% to not more than 1.0% of V, over 0% to not more than 0.5% of Al, over 0% to not more than 0.5% of Zr, over 0% to not more than 0.5% of B, over 0% to not more than 0.2% of a rare-earth element, over 0% to not more than 1.0% of Co, over 0% to not more than 1.0% of Ta and over 0% to not more than 1.0% of Bi, the balance being substantially Fe. Cr, Mo and N are within the range defined by the following expression [i]:The metal structure of the stainless steel is 45 to 80% in the area ratio alpha% of a ferritic phase therein. Cr and N are further within the range defined by the following expression [ii]:
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