Ultrasonic method for evaluation of resistance spot welding

摘要

A new ultrasonic method for evaluation or monitor of the resistance spot welding process is introduced. The method is based on electrode built-in ultrasonic transducer technology by measuring acoustical signals transmitted through the weld region on line. The transmitted signal is affected by temperature changes in the welded region during solidification and cooling of the melting pool. Parameters of the maximum thermal expansion, the slope of time delay and the range of the TOF are used to evaluate the weld quality.