咬边缺陷对超声冲击处理焊接接头疲劳性能的影响

 结合国产1 6Mn低合金中强钢,进行了使用超声冲击法提高含咬边缺陷的十字型焊接接头疲劳强度、延长其疲劳寿命的研究。结果表明:咬边等焊接缺陷降低焊接接头疲劳强度(与不含明显上述缺陷的试件相比)约10%～20%左右;超声冲击处理后,含咬边缺陷的(焊趾处)1 6Mn钢十字接头的疲劳强度提高66%,疲劳寿命提高10～40倍;与不含焊接缺陷的焊态试件相比,提高疲劳强度32%,提高疲劳寿命2～7倍;咬边缺陷对冲击处理后焊接接头的疲劳性能仍有不利的影响。

INFLUENCE OF UNDERCUTS ON FATIGUE PROPERTY OF WELDED JOINTS WITH ULTRASONIC PEENING TREATMENT

Some weld defects , such as undercuts , often exist in the surface at the weld toe. These defects greatly affect the capability of the weld subjected to dynamic loading and fatigue cracks usually initiate from these zones with defects . At present, no method using ultrasonic peening technique to treat weld structure with defects and to improve fatigue strength has ever been reported yet at home. Combining with low alloy middle strength steel 16Mn,a study of increasing the fatigue strength and raising fatigue life was carried out . Compared with specimens without defects, the fatigue strength of specimens with undercuts has been increased by 10%~20%. It also shows that with ultrasonic peening treatment, the fatigue strength of the cruciform weld joint of steel 16Mn has been increased by 66%, and the fatigue life by 10~40 times. Compared with as welded specimens with no defects, the fatigue strength has been increased by 32%, and the fatigue life by 2~7 times. Undercuts have adverse effects on fatigue property of weld joints under peening conditions.