Duplex Stainless Steel Pipe

Abstract: Provided is a duplex stainless steel pipe which has both high strength and excellent corrosion resistance. A duplex stainless steel pipe according to the present disclosure contains, in mass%, 0.030% or less of C, 0.20-1.00% of Si, 0.5-7.0% of Mn, 0.040% or less of P, 0.020% or less of S, 0.100% or less of Al, 4.0-9.0% of Ni, 20.0-30.0% of Cr, 0.5-2.0% of Mo, 1.5-3.0% of Cu, 0.15-0.30% of N, 0.01-0.50% of V, 0.030-0.300% of Nb, 0.10-0.50% of Co and 0.001-0.050% of Sn. This duplex stainless steel pipe has a microstructure which comprises 35.0-65.0% by volume of ferrite, not less than 0% but less than 1.0% by volume of a s phase, with the balance being made up of austenite. The non-solid solution Nb content is 0.008% by mass or more, the ratio of the non-solid solution Nb content to the non-solid solution Al content is 1.0 or more, and the yield strength is 655 MPa or more.

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