镀锌层厚度对铝/镀锌板CMT搭接接头组织和性能的影响

Effects of thickness of zinc layer on microstructure and properties of CMT lap welding joint between aluminum and galvanized steel

关键词:  冷金属过渡|铝|镀锌板|搭接|镀锌层厚度

Key words:  cold metal transfer|aluminum|galvanized steel sheet|lap|thickness of zinc layer

摘要:

文中研究厚度分别为10，30，60 μm (依次为1号，2号，3号)的镀锌层 对6082铝合金/镀锌板搭接接头组织和性能的影响，结果表明，1号焊缝成形较差，边缘有锌层烧蚀，3号焊缝形貌较美观，润湿性较好；1号和3号焊接接头拉伸性能较差，2号的焊接接头拉伸承载力达到9 519.5 N；镀锌层主要影响了富锌区和界面区，发现富锌区有枝晶和裂纹生成，界面区的金属间化合物均为Fe-Al-Zn化合物，仅在界面中间位置附近生成，3号的化合物层达到4 ~ 6 μm，1号和2号的化合物层为1 ~ 2 μm. 综上所述，合适的镀锌层厚度才能得到性能良好的焊接接头.

Abstract:

It aimed to investigate that effects of the thickness of zinc coating on the microstructure and properties of 6082 aluminum alloy/galvanized steel joint. The thickness of zinc layer was 10, 30 and 60 μm(No.1, No.2, No.3), respectively. The results showed that the No.1 weld shape was poor, with zinc layer ablation of the edge; and the appearance of No.3 weld seam was better and the wettability was better. Tensile properties of No.1 and No.3 welded joint was poor, and the tensile bearing capacity of the No.2 weld seam was 9 519.5 N. The zinc layer mainly affected the zinc-rich zone and the interfacial zone, and the zinc-rich zone had dendrites and cracks. The intermetallic compounds in the interfacial zone were Fe-Al-Zn compound, which formed only in the vicinity of the intermediate position of the interfacial zone. The No.3 compound layer produced was 4 ~ 6 μm, and the No.1 and No.2 compound layer was 1 ~ 2 μm. In summary, a suitable galvanized layer thickness was required to obtain a welded joint with good performance.