MARTENSITIC STAINLESS STEEL TUBE

摘要

A martensitic stainless steel tube being excellent in the resistance to stress corrosion cracking in a heat affected zone, which has a chemical composition, in mass %, wherein C: less than 0.0100 %, N: less than 0.0100 %, Cr: 10 to 14 % and Ni: 3 to 8 %, or, further suitable amounts of Si, Mn, P, S and Al are contained, and further one or more of Cu: 4 % or less, Co: 4 % or less, Mo: 4 % or less and W: 4 % or less and one or more of Ti: 0.15 % or less, Nb: 0.10 % or less, V: 0.10 % or less, Zr: 0.10 % or less, Hf: 0.20 % or less and Ta: 0.20 % or less are contained in such a manner that Csol defined by Csol = C - 1/3 X Cpre is less than 0.0050 %, where Cpre = 12.0{Ti/47.9 + 1/2(Nb/92.9 + Zr/91.2) + 1/3(V/50.9 + Hf/178.5 + Ta/180.9)-N/14.0}, provided that Cpre = 0 is taken when Cpre < 0. The martensitic stainless steel tube may further contain one or more of Ca, Mg, REM and B. The above composition allows the prevention of the grain boundary stress corrosion cracking appearing in a heat affected zone.