METHOD FOR MINIMIZING FATIGUE DAMAGE IN WELDED STRUCTURE, TOOL FOR FORMING STRIKE MARK, AND WELDED STRUCTURE

摘要

A method for minimizing fatigue damage in a welded structure by minimizing the fatigue damage produced in the welded portion of the welded structure. In this method, a substantially linear weld bead is curved in an arc-shape along a direction that transverses the weld bead at a right angle on the surface of a base material adjacent to the bead in the welded portion, and a strike mark is formed through hammer peening or ultrasonic shock peening using a tool for forming a strike mark having at the tip a strike-mark-forming surface with the center of curvature skewed to one side of two end surfaces mutually parallel along the weld bead; a strike mark is formed on the surface of the base material adjacent to the substantially linear and curved weld bead through hammer peening or ultrasonic shock peening using a tool for forming a strike mark having at the tip a planar strike-mark-forming surface with an overall circular or elliptical shape; and fatigue damage on the welded portion is minimized by introducing compressive residual stress in the vicinity of a weld bead toe with the tool for forming a strike mark.