送丝速度对6061铝合金/DP590镀锌钢CMT点塞焊接头性能的影响

Effects of Wire Feeding Speed on Properties of CMT Spot Plug Welding Joint of 6061 Aluminum Alloy and DP590 Galvanized Steel

采用ER4043铝合金焊丝,对6061-T6铝合金和DP590镀锌钢板进行了冷金属过渡（CMT）点塞焊试验。通过改变送丝速度得到了不同的焊接试样,并对试样金属过渡层的微观组织和力学性能进行了分析测试。结果表明：金属过渡层的厚度与焊接热输入有关。随着送丝速度的增加,焊接热输入增加,金属过渡层的厚度增大;靠近铝一侧的过渡层金属间化合物主要是Fe Al3,而靠近钢板一侧的金属间化合物主要是Fe2Al5。接头的拉伸载荷随金属过渡层厚度的增大先增加,当金属过渡层的厚度达到16.71μm时,拉伸载荷急剧下降。为保证铝钢焊接的强度,金属过渡层的厚度必须保持在适当的范围内。

6061-T6 aluminum alloy and DP590 galvanized steel sheets were joined by using cold metal transfer spot plug welding with ER4043 aluminum alloy wire as filler wire. The welding samples were prepared by changing the wire feeding speeds. The mechanical properties and microstructure of the intermetallic compounds（IMC） layer of the samples were observed and tested. The results show that the welding heat input has directly impact on the thickness of IMC layer. With the increase of wire feeding speed, the welding heat input increases and the thickness of IMC layer increases. The intermetallic compound in the transition layer near the aluminum side is mainly Fe Al3, while the intermetallic compound is Fe2 Al5 near the side of steel plate. With the increase of the thickness of IMC layer, the tensile load increases firstly, and then it decreases dramatically when the thickness of IMC layer increases to 16.71 μm. In order to ensure the strength of aluminum and steel welding, the thickness of the IMC layer must be kept within a proper range.