In fact, linear friction welding is a solid welding technology with the same principle as rotary friction welding. Under the action of welding pressure, the weldment moves back and forth along the linear direction amplitude, causing friction adhesion and friction heat. When the friction surface reaches the viscoplastic state, the metal in the welding area flows plastically under the action of pressure to form flash. Applying upset pressure, the metal in the welding area diffuses and recrystallizes into one, completing the entire welding process.