电极失效的影响
(湖北汽车工业学院 材料工程系，十堰 442002)
摘 要: 利用SEM、 EDX和XRD等方法分析了在点焊镀锌钢板时电极表面熔敷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(1 200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。
关键字: 电极失效；点焊；镀锌钢板；TiC涂层
（ Department of Materials Engineering,
Hubei Automobile Industrial Institute, Shiyan 442002, China）
Abstract: The effect of TiC coating on electrode tip surface on electrode degradation during resistance spot welding zinc coated steel was investigated by SEM, EDX and XRD. The results show that the electrode degradation mechanism is basically caused by wear due to the fracture of local welding between the electrode tip surface and zinc coated sheet steel happened at electrode surface and alloying between electrode and zinc on coated steel during resistance spot welding zinc coated steel. The service life of CuCrZr electrode with TiC coating (1 200 welds) is 2.4 times of that of uncoated CuCrZr electrode (500 welds). The reason of the TiC coating increasing electrode service life is that the TiC particles contained in the coating deposits can stop local welding between the electrode tip surface and zinc coated sheet steel and decrease alloying between electrode and zinc on zinc coated steel during resistance spot welding zinc coated steel.
Key words: electrode degradation; resistance spot welding; zinc coated steel; TiC coating
