Abstract: A welding method of a diffusion bonded structure in which the diffusion bonded structure formed by diffusion bonding metal parts to each other is bonded to another part by fusion welding includes a buffer layer forming step of forming a buffer layer in a welding region including a diffusion bonded joint of the diffusion bonded structure, the buffer layer having greater ductility than the diffusion bonded joint, and a welding step of bonding the welding region in which the buffer layer is formed to the another part by performing the fusion welding from above the buffer layer.

Abstract: A method of bonding metal members includes a stacked body forming step of forming a stacked body by putting an insert material between a first metal member and a second metal member formed of carbide-containing Ni alloys or carbide-containing Fe alloys, and a solid phase diffusion bonding step of forming a metal member joint body by heating and pressurizing the stacked body to perform solid phase diffusion bonding, wherein the insert material contains Ni having a content higher than an Ni content of the first metal member and the second metal member when the first metal member and the second metal member are formed of the carbide-containing Ni alloys, and contains Fe or Ni having a content higher than an Fe content of the first metal member and the second metal member when the first metal member and the second metal member are formed of the carbide-containing Fe alloys.

Abstract: A welding method of a diffusion bonded structure in which the diffusion bonded structure formed by diffusion bonding metal parts to each other is bonded to another part by fusion welding includes a buffer layer forming step of forming a buffer layer in a welding region including a diffusion bonded joint of the diffusion bonded structure, the buffer layer having greater ductility than the diffusion bonded joint, and a welding step of bonding the welding region in which the buffer layer is formed to the another part by performing the fusion welding from above the buffer layer.