| 摘要 |
A welded joint of duplex stainless steel, which can suppress precipitation σ phase under high heat input welding, is excellent in SCC resistance under high-temperature chloride environments. A weld metal of the welded joint 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. The weld metal satisfies Expressions (1) and (3):
2.2Cr+7Mo+3Cu>66 (1)Cr+11Mo+10Ni−12(Cu+30N)<100 (3)
where a content (mass percent) of each element in one of the base metal and weld metal is used for each element in Expressions (1) and (3). |
| 主权项 |
1. A joint of duplex stainless steel comprising:
a base metal; and a weld metal, wherein the base metal consists of, 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: more than 2.00% and at most 4.00%, Ni: 4.00 to 8.00%, Cr: 20.0 to 30.0%, Mo: 0.50 to 2.00%, N: 0.100 to 0.350%, and sol. Al: at most 0.040%, the balance being Fe and impurities, the base metal satisfies Expression (1) and Expression (2), the weld metal 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 0.010%, Cu: 0.10 to 0.8%, Ni: more than 8.00 and at most 12.00%, Cr: 20.0 to 30.0%, Mo: 1.00 to 4.00%, N: 0.100 to 0.350%, sol. Al: at most 0.040%, O: at most 0.035%, the balance being Fe and impurities, and the weld metal satisfies Expression (1) and Expression (3):
2.2Cr+7Mo+3Cu>66 (1)Cr+11Mo+10Ni−12(Cu+30N)<0 (2)Cr+11Mo+10Ni−12(Cu+30N)<100 (3)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) to Expression (3), wherein the joint has an area fraction of a sigma phase, which is less than 1%. |
