To provide a welded structure made of a low thermal expansion coefficient alloy which has a welding metal excellent in solidification cracking resistance, reheat cracking resistance, and toughness in very low temperatures, and also to provide a welding material for a low thermal expansion coefficient alloy which has a large capacity to secure performance and an excellent manufacturability.
A welding metal of the welded part in the welded structure includes: 30-45% Ni; 0.01-0.5% C; 0.01-0.5% Si; 0.01-1.0% Mn; and 0.0002-0.02% Al, and further includes 0.1-4% in total of at least one of Ta and Hf, and the balance Fe and impurities. The impurities include ≤0.015% S, ≤0.015% P, and ≤0.05% O(oxygen). The welding material has the same chemical composition as the welding metal except that the welding material includes >1.5% but ≤6% Ta or >0.1% but ≤6% Hf, or >0.1% but ≤6% in total of Ta and Hf (in this case, Hf exceeds 0.1%).
OGAWA KAZUHIRO
IKEBE MASATO
KUBO NAOSHIGE
YAMAMOTO SHUJI
EDAMITSU TAKEHIKO
OSAKA GAS CO LTD
Mikiji Sugioka