不同搭接间隙的电子束焊搭接接头的疲劳性能

Fatigue properties of electron beam welding overlap joints with different overlap gaps

对不同搭接间隙的电子束焊搭接接头的疲劳性能进行分析,确定搭接间隙对试样疲劳S—N曲线的影响。结果表明:不同搭接间隙电子束焊搭接接头的疲劳裂纹均启始于间隙尖端,沿焊缝表面板热影响区扩展,最终导致搭接焊接头疲劳破坏,即疲劳断裂主要是搭接间隙尖端的应力集中所引起的;搭接焊间隙对电子束搭接焊接头疲劳性能有较大影响,间隙增大应力集中增加,因而其疲劳性能降低。

The fatigue properties of electron beam welding overlap joints with different overlap gap were analyzed, and the effect of the overlap gap on the S--N fatigue curves of samples were studied. The results show that all of the fatigue cracks of electron beam welding overlap joints initiate at the gap near the weld surface, and extends along the heat affected zone （HAZ）, eventually leading to fatigue failure. In other words, the fatigue cracks are caused by the stress concentration of the overlap gap near the weld surface. Thus, the overlap gap is one of the significant impacts on the fatigue properties of electron beam welding overlap joints, and when the overlap gap increases, the stress concentration increases, the fatigue properties decreases.