Evaluation of corona bond strength of resistance spot welding

A simple method to evaluate the strength of corona bond of resistance spot welding is proposed and verified by removing the nugget of welded specimen before conducting a cross tension test. The strength of the corona bond is evaluated using thin steel sheets of different strengths. The result indicates that the higher the strength of the steel sheet, the higher the strength of the corona bond. A tensile test of the corona bond part is conducted using the small tensile test technique to verify the corona bond strength. A comparison of the stress value at the same strain (1%) indicates that the stress of the small tensile test is in the order of the strength of the steel sheet.