| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To more improve the reliability of a welded structure obtained by using metallic sheets by providing a method for improving the fatigue strength of a lap welded joint obtained by lapping two sheets of metallic sheets and welding the central parts, and a method for producing a welded structure using the same. <P>SOLUTION: In the method for improving fatigue strength, the vicinities of the welded toe parts in a lap welded joint obtained by lapping two sheets of metallic sheets with sheet thicknesses t1 and t2, and welding the central parts are struck with ultrasonic vibration terminals. In the surface of the metallic sheet with the sheet thickness t1, provided that either welded toe part is defined as a first original point, the other welded toe as a second original point, and the diameter D of the ultrasonic vibration terminals is 2 to 8 mm, also, the relative position of the central axis of the ultrasonic vibration terminals to the first original point is defined as x1, and the relative position thereof to the second original point as x2, as to the metallic sheet with the sheet thickness t1, both the positions of that satisfying -t1≤x1≤t1 and that satisfying -t1≤x2≤t1 are struck with the ultrasonic vibration terminals. <P>COPYRIGHT: (C)2004,JPO</p> |
