| 摘要 |
PROBLEM TO BE SOLVED: To provide a manufacturing method of a circumferential weld joint of a steel tube having a heat-affected zone with excellent intergranular stress corrosion cracking resistance. SOLUTION: When forming a circumferential weld by butting ends of martensitic stainless steel tubes to each other, and performing the welding consisting of a plurality of weld passes in the circumferential direction, the welding is performed while adjusting the subsequent weld pass so that the heat cycle to improve the intergranular stress corrosion cracking resistance is applied to a HAZ (heat affected zone) heated so that the peak temperature Tp of an inner surface layer of the steel tubes is≥950°C by the welding heat cycle based on at least one welding pass. More specifically, the weld pass of the final layer is the weld pass exceeding A1 point which is the lower limit temperature of generating the austenitic phase of≥1vol.%. Further, at least one weld pass out of the subsequent weld pass is the weld pass with Tp exceeding A1 point and≤950°C, and the following weld pass is the weld pass with Tp not exceeding A1 point. The subsequent weld passes are the weld passes with Tp not exceeding A1 point, and the total heat input parameter Ptotal of the subsequent weld passes is≤12,500 or≥14,500. COPYRIGHT: (C)2006,JPO&NCIPI |
