Friction-stir welding method for titanium alloy T-joint

The invention discloses a friction-stir welding method for a titanium alloy T-joint. A face plate of the titanium alloy T-joint is placed on a web by a lap joint method to form a T-shaped structure, the web is clamped by the opposite sides of the two process pads, the face plate is placed on the two process pads, and welding bead back protection devices for inert gas flows are arranged in the edges of the two process pads close to the angle between the face plate and the web along the length direction; and friction-stir welding is performed by using a smooth-surface cone stirring head. The friction-stir welding is as follows: a pre-made hole is processed first at the beginning of the welding bead on the top side of the face plate; then the stirring head is inserted into the pre-made hole;the stirring head continues to rotate for 5-10 seconds after the stirring head is inserted in place; then the stirring head moves along the length of the welding bead for welding; the stirring head continues to rotate for 5-9