工艺参数对铝/钢激光搭接焊接头质量的影响

Effect of process parameters on the quality of laser overlap welding joints of aluminum to steel

采用机器人激光焊接技术对车用6016铝合金与DC06低碳钢平板试样进行了钢上铝下搭接焊试验,研究了激光功率(P)和离焦量(f)对接头成形与力学性能的影响。结果表明,激光功率为800 W,离焦量为+2 mm,焊接速度为0.07 m·s^(-1)时,熔池的中上部生成大量塑韧性良好的珠光体组织,接头的平均抗拉剪力达到最大,为81.3 N·mm^(-1)。降低激光功率,由于焊缝有效结合面积小,力学性能降低;增大激光功率,铝侧熔深和熔宽逐渐增大,焊缝/铝界面生成金属间化合物数量增多,接头力学性能降低。离焦量从-1 mm增大到+3 mm过程中,焊接缺陷逐渐消失,焊缝成形得到了改善,铝侧熔深与熔宽逐渐减小,焊缝/铝界面金属间化合物数量减少,接头力学性能先增大再减小。

The overlap welding experiments of 6016 aluminum alloy and DC06 low carbon steel thin plate were carried out by using robotic laser welding technology.The effects of laser power(P)and defocusing distance(f)on the forming quality and mechanical property of the joint were studied.Experimental results show that a large number of pearlite structures with good plasticity and toughness are formed in the middle and upper part of the molten pool when the laser power is 800 W,the defocus distance is+2 mm and the welding speed is 0.07 m·s^(-1).The average tensile shear strength of Al/steel dissimilar joints reaches the maximum of 81.3 N·mm^(-1).The mechanical properties of the weld is reduced due to the small effective bonding area of the weld when reducing the laser power.With the increase of laser power,the penetration depth and weld width of aluminium side increase gradually,the number of intermetallic compounds formed at the weld/aluminium interface increases,and the mechanical properties of joints decrease.When the defocusing distance increases from-1 mm to+3 mm,the welding defects disappear gradually,the weld formation is improved,the penetration depth and width of aluminium side decrease gradually,the number of intermetallic compounds at the weld/aluminium interface decreases,and the mechanical properties of the joints increase first and then decrease.