Ultrasonic butt welding of thick metal plate specimens using a large capacity static induction thyristor power amplifier

Welding characteristics of an ultrasonic butt-welding system are studied. The ultrasonic vibration source used has eight 19- or 15-kHz bolt-clamped Langevin-type PZT transducers of 50-mm diameter and it is driven by a 50 or 100 kW solid-state power amplifier. The vibration power capacity of the 15-kHz system is 50% larger than that of the previously designed 19-kHz system. To improve the matching condition, the matching circuit must be adjusted according to welding load condition and vibration amplitude. Welding specimens of pure aluminum, anticorrosive aluminum, and copper plates 6 to 10 mm in thickness were successfully joined end to end. The required input power for joining aluminum or anticorrosive aluminum and copper plate specimens is about 7-9 kW/cm²