提高焊接接头疲劳强度的超声冲击法与TIG熔修法之比较

采用Q2 35B十字接头试件 ,就改善焊接接头疲劳强度的超声冲击法与TIG熔修法进行了全面对比。结果表明 :超声冲击处理对焊趾区硬度的影响不如TIG熔修明显 ;TIG熔修对焊趾几何外形的改善程度好于超声冲击法 ;TIG熔修处理工艺在焊趾区引入了残余拉应力 ,而超声冲击在焊趾区形成了较大数值的压缩应力。Q2 35B十字焊接接头经TIG熔修后 ,其疲劳强度 (2× 10 6 )提高 5 1% ,低于超声冲击处理对相同试件的疲劳强度 (2× 10 6 )改善程度 (6 4% )。

COMPARISON OF ULTRASONIC PEENING METHOD ON IMPROVING THE FATIGUE STRENGTH OF THE WELDED JOINTS WITH TIG DRESSING METHOD

Ultrasonic peening method is proved for improving the fatigue strength the welded joints by previous examinations. It is very necessary to compare the ultrasonic peening method with the TIG dressing method, because the latter is used widely. In this paper, a full comparison is done on the two methods by Q235B cruciform welded joints. The results show: impact effect of hardness at weld toe by ultrasonic peening is not great than treatment by TIG dressing. Improvement of geometry of weld toe by TIG dressing is better than treatment by ultrasonic peening. Residual extend stress is produced at weld toe by TIG dressing, while compressing stress of high values by ultrasonic peening. The fatigue strength of the Q235B cruciform welded joints after TIG dressing can be improved, but the results is not as good as the ultrasonic peening treatment for the same specimens.