초음파 충격 피닝이 용접부의 피로수명에 미치는 영향

초록

Most cracks in the weld structure occur and grow on the weld toe, reaching a certain size, resulting in breakage if the structure no longer supports the working load. The area where weld metal and parent metal meet each other is very weak in terms of fatigue strength due to microstructural change and tensile residual stress. To improve the fatigue strength of the weld joint, ultrasonic impact peening is widely used. Peening makes the microstructure fine, smoothes the rough surface, and relieves stress concentration. In this study, we developed ultrasonic peening equipment, manufactured welded specimens with SM490A steel plate, and investigated the effect of ultrasonic impact peening on the fatigue lifetime of the welded specimens.