301L搭接激光焊接接头拉伸过程的弹塑性演变及断裂数值分析

Numerical Analysis of Elastic-Plastic Deformation Evolution and Fracture Behavior in Tensile Process of Laser Lap Welded 301L Joints

采用数值分析方法,研究了301L不锈钢不同厚度板的非熔透搭接激光焊接接头在拉伸过程中的弹塑性演变、应力分布和拉伸断裂行为。建立了激光焊件的有限元模型,模拟得到的焊件拉伸曲线与实验结果有较好的一致性;随着拉伸载荷的增大,焊接试样塑性变形从靠近焊缝界面的母材向焊缝界面和母材两个方向扩展。随着焊缝熔宽/板厚比的增大,焊接试样的塑性应变区从焊缝界面附近逐渐扩展到母材内,拉伸断裂位移随着塑性变形区的增大而增大。当焊缝熔宽与板厚之比大于0.75时,焊件的断裂位移量大于5mm,焊件有较高的断裂强度,激光焊缝的剪切断裂强度约为794MPa。

The elastic-plastic deformation evolution, stress distribution and tensile fracture behavior during the tensile process of laser non-penetrating lap welded joints of the 301L stainless steel plates with different thicknesses are studied by the numerical analysis methods. The finite element model of laser welded joints is established and the simulated tensile curves of welded joints are in a relatively good agreement with the experimental results. With the increase of tensile load, the plastic deformation of welded specimens extends from the base metal near the weld interface to both of the weld interface and the base metal. In contrast, with the increase of the ratio of weld width to plate thickness, the plastic strain zone of welded specimens extends gradually from the vicinity of weld interface to the base metal. The tensile fracture displacement increases with the increase of plastic deformation zone. Moreover, when the ratio of weld width to plate thickness is higher than 0.75 and the fracture displacement of welded specimens is larger than 5 mm, the fracture strength is relatively high and the shear fracture strength of laser weld is about 794 MPa.