镀锌钢板电阻点焊涂层电极与普通电极寿命分析

Investigation on life of coated electrode and traditional electrode for resistant spot welding of Zn-coated steels

为增加镀锌钢板电阻点焊电极寿命,在普通铬锆铜电极表面沉积镍和金属陶瓷涂层后,研究涂层电极与无涂层普通电极的寿命.结果表明,相同条件下,涂层电极使用寿命大约是普通电极使用寿命的2.5倍;涂层电极抗塑性变形能力明显高于普通电极;普通电极端面有明显坑蚀、裂纹、合金层、自愈合层,而电极表面涂层能有效防止镀锌钢板电阻点焊过程中由于锌的扩散导致的粘连、剥离,从而减少合金元素Zn向电极端面的扩散,防止锌和电极合金形成脆性金属间化合物.

A nickel and a metallic ceramic coating were deposited on to the end surface of a traditional Cr-Zr-Cu resistant welding electrode in order to increase the life of electrode for resistant spot welding of Zn-coated sheet steels.The life of the coated electrode was approximately two and half times than that of the uncoated electrode under the same experimental conditions.The coated electrode had higher ability to prevent the electrode from plastic deformation during welding compared with the un-coated electrode.In addition,there were much more pitting,cracking,intermetallic alloy layer and self-healing layer on the end surface of un-coated electrode.As a barrier,the coatings on the surface of electrode could effectively prevent the adhesions,stripping,and then significantly reduce the diffusion of Zn from the surface of the electrode into the Cr-Zr-Cu electrode to form brittle intermetallic compounds.