| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing a stainless steel pipe containing 20 mass% or more Cr, in a cooling step after distortion removal annealing, a Cr-depleted layer is hardly generated on a grain boundary, and as a result, the stainless steel pipe shows excellent intergranular corrosion resistance against acid dew condensation water generated on the outer surface of a steel pipe in an actual machine use environment.SOLUTION: A method for manufacturing a stainless pipe includes: a step of manufacturing a steel pipe using a steel having a component composition of, by mass%, C:0.01-0.10%, Si:0.10 -2.0%, Mn:0.10-2.0%, P:more than 0% and 0.045% or less, S: more than 0% and 0.01% or less, Cr:20-30%, Ni:15-25%, N:0.10-0.35%; B:0.0005-0.05%; Nb:0.10-0.60%, and Ta:0.20-1.00%, and the balance Fe with inevitable impurities; a step of subjecting the steel pipe to a solid solution heat treatment; and a step of subjecting the steel pipe to a re-heating treatment at 800-1,050°C for 5 minutes or more, in this order.SELECTED DRAWING: None |
