NI-BASED ALLOY LARGE MEMBER, NI-BASED ALLOY WELDED STRUCTURE USING THE SAME, AND METHOD FOR MANUFACTURING THE STRUCTURE

摘要

PROBLEM TO BE SOLVED: To provide an Ni-based alloy large member that can be restrained from hot cracking, an Ni-based alloy welded structure using the Ni-based alloy large member, and a method for manufacturing the structure.SOLUTION: The Ni-based alloy large member having strip segregation of a carbide in a base material is formed with a homogeneous modified layer (a region A) on a welding groove surface by treatment using a friction stirring treatment method and solution treatment. An Ni-based alloy welded structure is manufactured by welding the Ni-based alloy large member so that the penetration depth of welding is shallower than the thickness of the modified layer.