Composite welding method and welding structure of T-shaped welding joint

The invention discloses a composite welding method and a welding structure of a T-shaped welding joint. The method comprises the following steps that a mounting groove is machined in a cover plate, and a sinking step is machined on a rib plate; pre-assembling the cover plate on the surface of the rib plate, and checking the contact area; demagnetizing the welding positions of the cover plate and the rib plate; the surfaces of the cover plate and the rib plate are cleaned, and dirt is cleaned; brazing filler metal is fixed to the sinking step of the rib plate; the rib plate component is assembled on the tool, and a cover plate is assembled; performing primary spot welding fixation on the cover plate and the rib plate; the rib plate and cover plate assembly part is put into vacuum electron beam welding equipment to be fixed, the equipment is started for vacuumizing, and electron beam equipment is adopted for welding; preserving heat in a vacuum chamber for a period of time after welding, and discharging vacuum