Simulation of dipping instabilities in GMAW: effect of arc and power source characteristics

摘要

An improved mathematical model is used to simulate the stability and short-circuiting behavior of gas-metal arc welding (GMAW) for high and low currents. The effect of varying arc and power source characteristics is studied. The steady state stick-out voltage is equivalent to an added circuit resistance as far as stability is concerned. For realistic arc characteristics and constant voltage power the arc is unstable below 200A. However, dipping transfer requires the reduction of the voltage below the steady state value. High frequency dipping transfer at high current occurs at electrode extensions more than 16-20mm. The effect is different from previously reported and not yet satisfactorily understood or resolved. The slopes of the arc characteristics and the arc voltage gradient have no effect on the occurrence of dipping at high current.