| 摘要 |
PROBLEM TO BE SOLVED: To provide duplex stainless steel or a shaft which has characteristics of high strength, high toughness and high pitting corrosion resistance. SOLUTION: The duplex stainless steel for a shaft having excellent pitting corrosion resistance has a composition containing <=0.080% C, 0.10 to <1.50% Si, <=2.0% Mn, <=0.03% P, <=0.01% S, 4.0 to 10.0% Ni, 22.0 to 30.0% Cr, 1.0 to 3.0% Mo, <=1.5% (inclusive of zero) W, 1.0 to 3.0% Mo+0.5×W, >1.0 to 3.5% Cu, <=0.30% N and 0.0005 to 0.01% B, by mass and the balance substantially Fe. The C value is 2.00 to 2.60, D value is >=36.0, and the strength at 0.2% elongation at a room temperature is >=650 MPa.
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