多次补焊对A6N01铝合金焊接接头疲劳性能的影响

Influence of multiple repair welding on fatigue properties of A6N01 aluminium alloy

通过对多次补焊条件下A6N01铝合金焊接接头进行疲劳试验,获得了不同补焊条件下焊接接头的条件疲劳极限值以及不同区域的裂纹扩展速率,并分析其疲劳断口形貌。结果表明,随着补焊次数增加,接头疲劳极限值减小,三次补焊后其由98.8 MPa下降到89.7 MPa,仍然满足使用要求;焊缝区和热影响区裂纹扩展速率均增大,但热影响区抵抗裂纹疲劳扩展能力优于焊缝区。随补焊次数增加,焊缝区气孔缺陷增多以及热影响区过时效现象加剧是造成焊接接头疲劳性能下降的主要原因。

The fatigue tests of A6N01 MIG welding joints with multiple repair welding were conducted in this paper. The fatigue limits and fatigue crack propagation rate were obtained,and the morphology of fatigue fracture was also studied. The results show that the value of fatigue limit decreases with increasing repair welding times ;after three times repair welding,the value decreased from 98.8 MPa to 89.7 Mpa,which still can satisfy the use requirement. The fatigue crack propagation rates in weld zones and HAZ zones both increase,but the resistance against crack propagation of HAZ zone is superior to that of weld zones. The reason that multiple repair welding can deteriorate the fatigue properties is mainly attributed to the increase of porosity defect in weld zone and overaging in HAZ zone.