METHOD FOR WELDING STEEL MATERIAL TO NI-BASED SUPERALLOY, AND WELDING JOINT

摘要

When a turbine impeller (4) formed from an Ni-based superalloy and a rotor shaft (2) formed from a steel material are joined by being fused together via welding in a boundary portion, a mixing ratio of a welding metal (6) that is formed in the boundary portion by fusing together the Ni-based superalloy forming the turbine impeller (4) and the steel material forming the rotor shaft (2) is between 0.5 and 0.8. As a result, it is possible to obtain a sound welding joint in which there are no cracks in the boundary between the welding metal (6) and the Ni-based superalloy (4).