Dissimilar metal weld and its manufacturing method of large welded structures such as the turbine rotor

摘要

Provided are dissimilar metal welds including a buttering portion (22) with a small variation in strength distribution in a plate thickness direction, and its manufacturing method. Dissimilar metal welds are formed by welding two parent materials (20,23) having at least one of different compositions and different refining conditions through a buttering (22) for alleviating mismatch between one of the different compositions and the different refining conditions of the two members (20,23) and through a welded metal (24) for joining one of the parent materials (20,23) and the buttering (22). The buttering (22) is formed of welding metals laminated in a plate thickness direction, and a dilution ratio of the buttering (22) with the parent materials is 50% or less. Provided are the steps of performing butt welding on a dummy material (21) formed by increasing a groove depth by providing a member on a bottom side of a welding groove and on parent materials (20,23) by using the buttering (22); and processing a groove within a welding metal (24) formed of the buttering (22).