H340LAD+Z电阻点焊接头疲劳性能研究

Research on Fatigue Performance of H340LAD+Z Spot Welded Joint

开展了H340LAD+Z(1.2 mm)-H340LAD+Z(1.2 mm)点焊十字接头和点焊剥离接头疲劳性能及失效模式的研究工作。研究发现,点焊十字接头拉伸试验的最大力为9.0 kN,点焊剥离接头拉伸试验的最大力为1.9 kN,点焊接头硬度最大值为348 HV 1,位于熔核区内,点焊十字接头和点焊剥离接头的最大力-疲劳寿命曲线在双对数坐标轴下呈线性关系,且点焊十字接头的疲劳性能优于点焊剥离接头的疲劳性能。最后观察了点焊十字接头和点焊剥离接头的疲劳失效模式及疲劳断口形貌特征,2种接头的失效模式略有差别,疲劳断口形貌均由裂纹源和扩展区组成。

Research on the fatigue performance and failure modes of H340LAD+Z(1.2 mm)-H340LAD+Z(1.2 mm)spot welding cross joints and spot welding stripping joint was conducted.The study identifies that the maximum force of the spot welding cross joint tensile test is 9.0 kN,the maximum force of the spot welding stripping joint tensile test is 1.9 kN,and the maximum hardness of the spot welding joint is 348 HV 1 located at the nugget area,the spot welding cross joint and the maximum force-fatigue life curve of the spot welded stripping joint show a linear relationship under the logarithmic coordinate axis,and the fatigue performance of the spot welding cross joint is better than that of the spot welding stripping joint.Finally,the fatigue failure modes and fatigue fracture morphology characteristics of the spot welding cross joint and the spot welding stripping joint were observed.The failure modes of the two joints are slightly different,and the fatigue fracture morphology is composed of crack sources and expansion zones.