HIGH STRENGTH STAINLESS STEEL PIPE FOR LINE PIPE EXCELLENT IN CORROSION RESISTANCE AND METHOD FOR PRODUCTION THEREOF

摘要

A high strength stainless steel pipe for a line pipe excellent in corrosion resistance, which has a chemical composition, in mass %, that C: 0.001 to 0.015 %, Si: 0.01 to 0.5 %, Mn: 0.1 to 1.8 %, P: 0.03 % or less, S: 0.005 % or less, Cr: 15 to 18 %, Ni: 0.5 % or more and less than 5.5 %, Mo: 0.5 to 3.5 %, V: 0.02 to 0.2 %, N: 0.001 to 0.015 %, O: 0.006 % or less, with the proviso that C + 0.65Ni + 0.6Mo - 20C >= 18.5, Cr + Mo + 0.3Si - 43.5C - 0.4Mn - Ni - 0.3Cu - 9N >= 11.5 and C + N <= 0.025 are satisfied. Preferably, the pipe is subjected to a quenching-tempering treatment. The steel pipe may further contain 0.002 to 0.05 % of Al. It may further contain one or more selected from among Nb, Ti, Zr, B and W, and/or, Cu or Ca. The steel pipe preferably has a structure containing martensite, ferrite and retained gamma.