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 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 submerged arc welding apparatus of the present invention includes: a flux receiver for receiving and holding flux in an area formed by itself and a workpiece inside thereof when abutting against the workpiece on the open side; a flux feeder for supplying flux to the flux receiver; a welding torch for supplying a welding wire toward the workpiece with the tip disposed in the area where the flux is held; and a moving mechanism for moving the flux receiver and the welding torch along the direction of a welding line of the workpiece with the flux receiver abutting against the workpiece. A submerged arc welding method of the present invention includes: performing welding by opposing the welding torch to the workpiece and by moving the welding torch along the direction of the welding line with flux held in an area formed between the workpiece and the welding torch.

Abstract: A submerged arc welding apparatus 10 according to the present invention comprises: a flux receiver (12) for receiving and holding flux in an area formed by itself and a workpiece (1) inside thereof when abutting against the workpiece (1) on the open side; a flux feeder (24) for supplying flux to the flux receiver (12); a welding torch (32) for supplying a welding wire (34) toward the workpiece (1) with the tip disposed in the area where the flux is held; and a moving mechanism (36) for moving the flux receiver (12) and the welding torch (32) along the direction of a welding line (2) of the workpiece (1) with the flux receiver (12) abutting against the workpiece (1). In the submerged arc welding method of the present invention, comprises: performing welding by opposing the welding torch (32) to the workpiece (1) and by moving the welding torch along the direction of the welding line (2) with flux (11) held in an area formed between the workpiece (1) and the welding torch (32).