Abstract
The waveform analyzer containing minicomputer was developed. The computer system in this equipment is capable of sampling two channel simultaneously at rate up to a limit of 500 sampling per msec and storing 128, 000 data on each experiment. Waveform of arc voltage in short circuit transfer range of CO2 gas shielded arc welding was examined by this waveform analyzer. By setting up a certain threshold value, arc voltage wave was divided into two periods: short circuit period and arc period. In this study, the waveform in arc period was analyzed. The standard deviation of arc period (σ value) was related to arc stability. Arc stability decreased with the increase in σ value. σ value increased with higher arc voltage, higher welding current and longer wire extension, especially σ value was strongly influenced by the variation of arc voltage. Experimental formula for σ value, which evaluated the arc stability, was expressed by welding current, wire extension and arc voltage.
