焊接速度对铝/钢激光搭接焊接头质量的影响

Effect of Welding Speed on Quality of Laser Overlap Welded Joint of Aluminum and Steel

采用机器人激光焊接技术对车用6016铝合金与DC06低碳钢进行了钢上铝下搭接焊工艺试验,研究了焊接速度对接头成形与力学性能的影响,利用光学显微镜(OM)和万能拉伸试验机等试验设备对铝/钢搭接焊接头进行了显微组织与力学性能测试。结果表明,在激光功率为800 W,离焦量为+2 mm的条件下,均获得了良好的表面成形。焊接速度为0.07 m/s时,熔池内部生成大量塑韧性良好的珠光体组织,界面金属间化合物(IMC)数量少,应力集中系数最小,接头的平均抗拉剪力达到最大,为81.3 N。降低焊接速度,铝侧熔池金属间化合物数量显著增加;增大焊接速度,铝侧熔深与熔宽逐渐减小,界面金属间化合物数量减少。

The overlap welding process experiments of 6016 aluminum alloy(up)used for automobile and DC06 low carbon steel plate(down)were carried out by using robotic laser welding technology.The effects of welding speed on the forming quality and mechanical property of the joints were studied.The microstructure and mechanical properties of the overlap welding joint of aluminium and steel were tested by using optical microscope(OM)and universal tensile testing machine.The experimental results show that good surface formation is obtained under the conditions of laser power of 800 W and defocusing distance of+2 mm.When the welding speed is 0.07 m/s,a large number of pearlites with good plasticity and toughness form in the molten pool.The number of intermetallic compounds at the interface becomes small,and the stress concentration factor is the smallest.The average tensile shear force of Al/steel dissimilar joints reaches the maximum,which is81.3 N.With the decrease of welding speed,the number of intermetallics(IMC)in the molten pool at aluminium side increases significantly,while with the increase of welding speed,the depth and width of molten at aluminium side decrease gradually,and the number of intermetallics in the interface decreases.