Line pipe having a welded joint of duplex stainless steel

摘要

Provided is a welded joint of duplex stainless steel that can suppress precipitation of a à phase at the time of high heat input welding and is excellent in SCC resistance under high-temperature chloride environments. A weld metal of the welded joint of duplex stainless steel according to the present invention contains, in mass percent, C: at most 0.030%, Si: 0.20 to 1.00%, Mn: at most 8.00%, P: at most 0.040%, S: at most 0.0100%, Cu: at most 2.00%, Ni: 7.00 to 12.00%, Cr: 20.0 to 30.0%, Mo: 1 to 4%, N: 0.100 to 0.350%, sol. Al: at most 0.040%, and O: at most 0.035%, the balance being Fe and impurities, and the weld metal satisfies Expression (1) and Expression (3): 2.2 �¢ Cr + 7 �¢ Mo + 3 �¢ Cu 66 Cr + 11 �¢ Mo + 10 �¢ Ni - 12 Cu + 30 �¢ N 100 where a content (mass percent) of each element in one of the base metal and the weld metal is substituted into a symbol of each element in Expression (1) and Expression (3).