WELDED STRUCTURE MADE OF LOW THERMAL EXPANSION COEFFICIENT ALLOY AND WELD MATERIAL

摘要

In a welded structure and welded pipe, having members joined to each other by welding wherein, at least one of the members is formed of Fe-Ni-base low thermal expansion coefficient alloy, there is provided a welded structure and welded pipe having a weld metal free from cracking and achieving an excellent toughness and stress corrosion cracking resistance. Further, a welding material is provided which can form such a weld metal and is excellent in workability and weldability in fabrication. The weld metal comprises, on the weight % basis, Ni: 30 to 45 %, Co: 0 to 10 %, C: 0.03 to 0.5 %, Mn: 0.7 % or less, either one of or the total of Nb and Zr: 0.05 to 4 %, and rare earth element: 0 to 0.5 %, with impurities being P: 0.02 % or less, Al: 0.01 % or less, and oxygen: 0.01 % or less, wherein each of Si and S satisfies the following formulas 1 &cir& and 2 &cir& , where each element symbol in the following formulas 1 &cir& and 2 &cir& indicates the content (weight %) of each element. $$ $$