| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for forming a martenstic stainless steel material welded part excellent in the intergranular stress corrosion cracking (IGSCC) resistance and the hydrogen embrittlement resistance in the heat affective zone (HAZ). SOLUTION: When the welding part is formed by applying the welding to the martenstic stainless steel material contained by mass% of <0.015% C, <0.015% N, 10.0-14.0% Cr, 1.0-8.0% Ni and further, suitable contents of Si, Mn, P, S, Al and further, one or more kinds selected among Mo, Cu, W; after welding, to the welded part, a post-welding heat-treatment (PWHT) is applied by solidifying the following conditions, in which P1 defined with P1=(T+273)ä20+log (t/3600)}, äwherein, T: PWHT temperature (°C), t: PWHT holding time (s)} is≥15,500, and P2 defined with P2=20 log t+T-(A1+120), äwherein, A1: the lower limit temperature (°C) forming≥1 vol% austenite-phase at heating and holding for 20 sec after making 100 vol% martensite structure} is≤0 and PWHT holding time (t) is in the range of 60-100 s. In this way, the IGSCC resistance and the hydrogen embrittlement resistance in HAZ, are drastically improved. COPYRIGHT: (C)2008,JPO&INPIT |
