High peak power, burst mode operation of a multikilowatt CO2 laser for deep penetration welding

Abstract

A significant advancement in laser welding of heavy metal sections is presented. Operation of a photoinitiated, impulse-enhanced, electrically excited multikilowatt continuous wave (cw) laser in the pulse periodic regime results in significant improvement in weld penetration depth. High average power pulsed operation is made possible through the use of a low level trigger for a digitally controlled hydrogen thyratron pulser circuit. Peak optical powers on the order of 3 times the cw level are produced while maintaining multikilowatt average output power. A comparison of cw and pulsed welding of X70 pipeline steel is included. Burst mode welding with this system is found to yield up to a 50% increase in weld penetration with a superior weld profile when compared to cw welding at the same average power level.