SHOT APPARATUS FOR IMPROVING FATIGUE CHARACTERISTICS OF WELDED JOINT, METHOD FOR IMPROVING FATIGUE CHARACTERISTICS, AND METHOD FOR PRODUCING WELDED JOINT HAVING IMPROVED FATIGUE CHARACTERISTICS

摘要

Disclosed is a shot apparatus and method for improving the fatigue characteristics of a welded joint, the shot apparatus and method being capable of causing the tip of a shot pin (3) which moves in the weld line direction to autonomously move in the direction of the toe section (9) of the weld metal (8), without using a complicated mechanism and without special positional control. The shot apparatus is provided with: a shot mechanism unit (2) which performs shot; a supporting and pressing mechanism unit (5) which supports the shot mechanism unit and presses the shot pin onto the weld toe section; and a moving mechanism unit (6) which is loaded with the supporting and pressing mechanism unit and moves in the weld line direction. Within the supporting and pressing mechanism unit or between the supporting and pressing mechanism unit and the moving mechanism unit, there provided is an angular adjustment mechanism (10) which adjusts the angle formed by the center line in the axial direction of the shot pin and the surface of the material (7) being shot. Furthermore, a loosely shotting mechanism unit (4) which provides the degree of freedom in the movement in the direction perpendicular to the weld direction of the shot mechanism unit is provided between the shot mechanism unit and the supporting and pressing mechanism unit.