Welding tool for diffusion welding of annular parts

The utility model discloses an annular part diffusion welding tool which comprises a supporting plate, the supporting plate is provided with four guide fixing grooves which are of a structure shaped like a Chinese character'mi ', arc-shaped thrust blocks are arranged in the guide fixing grooves in a sliding mode, and sliding blocks used for pushing the thrust blocks to move in the radial direction of the guide fixing grooves are arranged in the thrust blocks. The bottom of the sliding block is of an inclined face structure inclining inwards. The outer surface of the thrust block is of a curved surface structure matched with the surface of a workpiece to be welded, and the inner surface of the thrust block is of an inclined surface structure matched with the bottom of the sliding block. The height of the thrust block is larger than that of a workpiece to be welded. According to the utility model, vertical force applied downwards is converted into horizontal force to extrude a welding workpiece, and diffusion w