点焊镀锌钢板时球形电极表面熔敷TiC涂层对电极失效的分析

Effect of TiC Coating in Electrode Tip Surface on Spheriform Electrode Degradation during Resistance Spot Welding Zinc Coated Steel

利用SEM、EDX和XRD等方法分析了在点焊镀锌钢板时球形电极表面熔敷TiC涂层对电极失效的影响。结果表明:点焊镀锌钢板时,球形电极的失效机制,主要是电极和镀锌板之间局部焊接的断裂发生在电极表面而导致的电极磨损,以及电极和镀锌板表面的锌之间的合金化。表面涂敷TiC的CuCrZr电极的寿命(1200点)是CuCrZr电极寿命(500点)的2.4倍,表面处理能提高电极寿命的主要原因是,在点焊镀锌钢板时表面涂敷的TiC层能阻碍电极和镀锌板之间的局部焊接和阻碍电极和镀锌板表面的锌之间的合金化。

The effect of TiC coating in electrode tip surface on spheriform electrode degradation during resistance spot welding zinc coated steel was investigated by SEM,EDX and XRD. The results show that spheriform electrode degradation mechanism was basically caused by wear due to fracture of local welding between the electrode tip surface and zinc coated sheet steel happen at electrode surface and alloying between electrode and zinc on zinc coated steel during resistance spot welding zinc coated steel. The service life of CuCrZr electrode with TiC coating (1200 welds) was 2.4 times of that of uncoated CuCrZr electrode (500 welds). The reason of the TiC coating can increase electrode service life is because that the TiC particles contained in the coating deposits could stop local welding between the electrode tip surface and zinc coated sheet steel and decreased alloying between electrode and zinc on zinc coated steel during resistance spot welding zinc coated steel.