The Role of Zinc Layer During Wetting of Aluminium on Zinc-coated Steel in Laser Brazing and Welding
The Role of Zinc Layer During Wetting of Aluminium on Zinc-coated Steel in Laser Brazing and Welding
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DOI：
10.1016/j.phpro.2014.08.080
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
M. Gatzen;T. Radel;C. Thomy;F. Vollertsen
中科院分区：
文献类型：
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作者：
M. Gatzen;T. Radel;C. Thomy;F. Vollertsen
镀锌钢的锌层是铝液在镀锌钢表面扩散的关键因素。对于工业钎焊和焊接工艺，这些锌涂层在许多情况下可以实现铝和钢之间的无熔剂连接。然而，锌对润湿过程有益作用的原因尚不完全清楚。对单个铝液滴在不同镀锌钢表面的润湿行为的基本研究表明，在室温和高温下，不同涂层厚度的影响在涂覆表面之间存在明显差异。本文介绍了铝和工业镀锌钢板的连续激光钎焊和焊接工艺。结果表明，在珠对板的激光束钎焊情况下，涂层厚度对产生的润湿角和长度有可测量的影响，而在重叠激光束焊接情况下，涂层厚度对产生的润湿角和长度没有显著影响。这可能与不同的传热条件有关。结果还强烈表明，要在镀锌表面上实现良好的润湿，仍然需要适当的氧化层初始分解。
The zinc layer of zinc-coated steel is known to be a crucial factor for the spreading of liquid aluminium on the coated surface. For industrial brazing and welding processes these zinc-coatings enable a fluxless joining between aluminium and steel in many cases. Yet, the reason for the beneficial effect of the zinc to the wetting process is not completely understood. Fundamental investigations on the wetting behaviour of single aluminium droplets on different zinc-coated steel surfaces have revealed a distinct difference between coated surfaces at room temperature and at elevated temperature regarding the influence of different coating thicknesses.In this paper the case of continuous laser brazing and welding processes of aluminium and commercial galvanized zinc-coated steel sheets are presented. It is shown that in the case of bead-on-plate laser beam brazing, the coating thickness has a measureable effect on the resulting wetting angle and length but does not have a significant impact in case of overlap laser beam welding. This might be linked to different heat transfer conditions. The results also strongly indicate that proper initialbreakup of oxide layers is still required to accomplish good wetting on zinc-coated surfaces.