板厚对不锈钢车体激光叠焊接头抗剪强度和疲劳强度的影响

为了研究板厚对不锈钢激光叠焊接头抗剪强度和疲劳强度的影响,该文针对0.8 mm+2 mm和2 mm+2 mm²种不同板厚搭配的不锈钢激光叠焊接头分别进行了拉伸试验和疲劳试验。结果表明,2 mm+2 mm接头的抗剪强度和疲劳强度均高于0.8 mm+2 mm接头。失效分析发现,2种接头的拉伸破坏由焊肉部位剪断引起的;2种接头的疲劳裂纹均萌生于2 mm未焊透板,裂纹起始位置在2个焊板之间靠近焊核附近未焊透板的热影响区,裂纹沿着焊核边缘向未焊透板外表面方向扩展,直至穿透未焊透板。对焊接接头部位的有限元受力分析可知,2种接头的应力集中程度的不同是造成它们抗剪强度和疲劳强度差异的主要原因。

Effect of plate thickness on shear strength and fatigue strength of laser lap welded joints for stainless steel car body

In order to investigate on effect of plate thickness on shear strength and fatigue strength of stainless steel laser lap welded joints,tensile tests and fatigue tests on stainless steel laser lap welded joints with two different plate thicknesses of 0.8 mm+2 mm and 2 mm+2 mm were conducted.The results showed that shear strength and fatigue strength of the 2 mm+2 mm joint were higher than those of 0.8 mm+2 mm.It was found by failure analysis that tensile fracture of the two joints was caused by shear fracture of weld,and fatigue cracks originated in heat-affected zone near the weld nugget on the inner surface of the incompletely welded plate.The crack propagated along the edge of the weld nugget to the outer surface of the incompletely welded plate until it penetrated the incompletely welded plate.It could be seen from the finite element force analysis of welded joints that the difference in the degree of stress concentration between the two joints was the main reason for the difference in their shear strength and fatigue strength.