| 摘要 |
<p>Problem to be Solved: To provide a duplex stainless steel excellent in the weldability during large heat input welding and excellent in the stress corrosion cracking resistance in a chloride environment containing corrosive associated gases. Solution: A duplex stainless steel that has a chemical composition consisting, by mass%, of C: 0.03% or less, Si: 0.2 to 1%, Mn: 5.0% or less, P: 0.040% or less, S: 0.010% or less, sol. Al: 0.040% or less, Ni: 4 to 8%, Cr: 20 to 28%, Mo: 0.5 to 2.0%, Cu: more than 2.0% and 4.0% or less and N: 0.1 to 0.35%, and optionally contains one or more selected from among V, Ca, Mg, B and a rare earth metal(s), with the balance being Fe and impurities; wherein the duplex stainless steel satisfies the relations of the following formulas (1) and (2): 2.2 �¢ Cr + 7 �¢ Mo + 3 �¢ Cu > 66 Cr + 11 �¢ Mo + 10 �¢ Ni < 12 �¢ Cu + 30 �¢ N
wherein the symbols of elements in formulas (1) and (2) respectively represent the contents (unit: mass%) of the elements in the steel.</p> |
