通过拉剪实验测定1.5 mm厚SUS304不锈钢点焊接头、胶焊接头的抗拉强度,并开展疲劳实验,获得不同应力水平下两种接头的疲劳寿命,得到两种接头的载荷-寿命曲线;借助扫描电镜分析接头疲劳失效过程.结果表明:当焊接电流为10.0 kA、焊接时间为80 ms、电极压力为0.5 MPa时,能获得较好的胶焊接头.在此焊接参数下,点焊接头、未固化胶焊接头和固化胶焊接头的平均失效载荷分别为12 825.5 N、10 345.6 N、10 022.9 N;在疲劳实验载荷-寿命曲线的有限寿命区内,SUS304不锈钢胶焊接头的疲劳强度均大于点焊接头;点焊接头和胶焊接头的疲劳失效形式主要由母材眉状裂纹失效和界面撕裂失效两种形式组成;胶焊接头的疲劳失效过程中,首先是胶层粘接失效,随后疲劳裂纹从板间内表面热影响区边缘萌生,沿板厚与板宽方向扩展直至发生疲劳失效.%Tensile shear test of spot welds and weld-bonded joints of 1.5 mm SUS304 austenitic stainless steel was made to acquire their tensile strength.Fatigue test of spot welds and weld-bonded joints was carried out under different levels of stresses,and two kinds of joint′s load-life curves were obtained.Scanning electron microscopy was used to explore the fatigue failure mechanism.Results showed that the relatively good parameters for weld-bonded joints were welding current 10.0 kA,welding time 80 ms,and welding pressure 0.5 MPa.Under this welding parameters,the tensile strength of spot welds,uncured weld-bonded and cured weld-bonded joints were 12 825.5 N,10 345.6 N and 10 022.9 N,respectively.Weld-bonded joints had a higher fatigue strength than spot welds.Fatigue failure modes of spot welds and weld-bonded joints were mainly composed of eyebrow failure and interfacial fracture mode.In the process of fatigue failure of weld-bonded joints,the rubber failure occurred first,then fatigue crack initiated from the heat affected zone edge between the inner surface and extended in the direction of thickness and width.
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