oil well stainless steel, oil well stainless steel pipe, and oil well stainless steel fabrication method.

摘要

oil well stainless steel, oil well stainless steel pipe, and oil well stainless steel fabrication method are the chemical composition of a stainless steel according to the present invention consisting of c: no more than 0,05%, si: not more than 0,5%, mn: 0,01 to 0,5%, p: not more than 0,04%, s: not more than 0,01% , cr: more than 16,0 and not more than 18,0%, ni: more than 4,0 and not more than 5,6%, mo: 1,6 to 4,0%, cu: 1.5 to 3.0%, ai: 0.001 to 10%, and no more than 0.050%, the balance being females and impurities, and satisfying formulas (1) and (2). furthermore, the microstructure thereof contains a martensitic phase and a ferritic phase which has a volume ratio of 1 to 40%, and the distribution ratio of the ferritic phase is higher than 85%. cr + cu + ni + mo ~ 25.5 (1) -8 s 30 (c + n) + 0.5mn + ni + cu / 2 + 8.2-1.1 (cr + mo) s -4 (2 )