6061Al-DP590冷金属过渡焊点焊件组织与性能

Microstructure and properties of 6061Al-DP590 welding joints welded by cold metal transfer spot welding technology

应用冷金属过渡焊技术对6061Al铝合金和DP590镀锌钢板进行搭接点焊,研究不同送丝速度下6061Al-DP590焊接试样焊点的宏观形貌,Fe、Al金属间化合物过渡层厚度及形貌和焊接试样的力学性能。结果表明：送丝速度分别为5、5.6和6.2 m/min时,Fe、Al金属间化合物过渡层的厚度分别为2.3、8和16μm;由于靠近钢板一侧冷却速度较快,容易形成平面晶,紧邻钢板一侧的Fe、Al金属间化合物过渡层界面较为平滑,而靠近铝板一侧由于Al-Fe合金结晶温度区间较大,容易形成柱状晶;当送丝速度为5.6 m/min,焊接速度为1.2 m/min、弧长修正为0时,焊接接头最大载荷可以达到4.5 kN,其力学性能为最佳。

The lap spot welding of 6061 Al aluminum alloy and DP590 galvanized steel plate was carried out by using cold metal transfer welding（CMT） technology. The macroscopic morphology of the 6061 Al-DP590 welded joints with different wire feeding speeds was studied,and the thickness and morphology of the Fe-Al intermetallic compounds transition layer and the mechanical properties of the welded specimens were investigated. The results show that the thickness of the transition layer of Fe-Al intermetallic compounds is2. 3 μm,8 μm and 16 μm when the wire feeding speed is 5 m/min,5. 6 m/min and 6. 2 m/min,respectively. Due to the rapid cooling rate near the side of the steel plate,the plane crystal is easily formed,and the interface of the transition layer of Fe-Al intermetallics next to the side of the steel plate is relatively smooth. But near the side of the aluminum plate,the columnar crystal is easily formed because of the large crystallization temperature range of Al-Fe alloy. When the wire feeding speed is 5. 6 m/min,the welding speed is 1. 2 m/min,and the arc length is corrected to zero,the welded joint exhibits the best mechanical properties with the maximum break load of 4. 5 kN.