| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for suppressing fatigue damage of a welded structure which can securely suppress the generation of fatigue damage such as a fatigue crack in the weld portion of a welded structure such as a steel bridge, and a tool for forming an impact trace.SOLUTION: As a tool for forming the impact trace on the surface of a base material adjoining the weld bead of a weld portion by hammer peening or ultrasonic shock peening, a tool 6 for forming the impact trace is used which has a planate impact trace formation surface 7 in the front end thereof, of which the width Rx along the direction intersecting the weld bead at a right angle is 1.5 mm or more, 3.0 mm or less, the length Ry along the weld bead is 3.0 mm or more, 6.0 mm or less, and the whole shape is formed to be elliptical. By using the tool 6 for forming the impact trace, the impact trace of which the maximum depth is 0.2 mm or more is continuously formed along the weld bead to introduce compression residual stress in the vicinity of the toe of the weld bead. |
