Tool and welding method suitable for welding waveguide window assembly of traveling wave tube

A tool is suitable for fixing a traveling wave tube waveguide window assembly to be welded and comprises a supporting part, the top of the supporting part is flatly arranged and suitable for supporting a waveguide window sealing piece, and a first protruding part protruding upwards is arranged in the middle of the upper surface of the supporting part and suitable for being embedded in a limiting hole formed in the waveguide window sealing piece; the waveguide window sealing piece is limited to rotate relative to the supporting part; the guide part is arranged above the supporting part, and a guide hole extending in the vertical direction is formed in the middle of the guide part; the window upper positioning piece is slidably arranged in the guide hole in a sleeved mode and limited to rotate relative to the guide part, the window upper positioning piece is suitable for abutting against the top of the waveguide window flange to apply downward pressure to the waveguide window flange so that the window piece can