Strengthening Techniques of Spot-welding Electrode Applied to Zinc Coated Steel
The poor weldability of zinc coated steel results in early failure of the resistance spot-welding electrodes.Hence,reinforcement of the electrode draws growing attention,and matrix enhancement and surface modification are two major technologies.The electrode is commonly cold worked copper alloy strengthened by Zr and Cr alloys.It can be further hardened by dispersion strengthening of the matrix with Al2O3,TiB2,ZrO2,and cryogenic treatment,surface treatment such as brush plate of Co,ion injection of W,electrospark deposition of TiC,TiB2 and TiN.All these methods are available to improve its lifetime.TiC based coating deposited on its surface by electrospark is a hopeful surface technology among them,which proves to be very effective by industrial applications.