ABSTRACT

The short electrode life is one of the most important problems associated with resistance spot welding of galvanised steel sheets. In this study, a nanolayered multi-layer CrN/(Cr,Al)N coating was deposited on the tip of the electrode by applying the cathodic arc physical vapour deposition process with the layer thickness of about 30 nm and an overall thickness of 1.1 µm. The electrode life test confirmed that the coating could extend the electrode life up to 125%. The coated electrode showed a significantly lower growth rate (∼0.3 µm per weld), in comparison to the un-coated one (∼1 µm per weld). The degradation of the electrode could be subdivided into two subsequent steps: the degradation of the electrode periphery and the degradation of the electrode tip. The CrN/(Cr,Al)N coating could effectively protect the electrode tip periphery from zinc adhesion and postpone the first stage electrode degradation which delayed the second one.

摘要

电极寿命短是与镀锌钢板电阻点焊相关的最重要问题之一。在这项研究中，通过应用阴极电弧物理气相沉积工艺，在电极尖端沉积了一层纳米多层 CrN/(Cr,Al)N 涂层，层厚约为 30 nm，总厚度为 1.1 µm . 电极寿命试验证实该涂层可使电极寿命延长125%。与未涂层电极（每个焊缝约 1 µm）相比，涂层电极显示出显着较低的生长速率（每个焊缝约 0.3 µm）。电极的退化可以细分为两个后续步骤：电极外围的退化和电极尖端的退化。CrN/(Cr,