A Study of Arc Length in Pulsed GTAW of Aluminum Alloy by Means of Arc Plasma Spectrum Analysis

This paper studied the arc length in pulsed GTAW of aluminum alloys by means of arc plasma spectral analysis. The intensity of Ar I spectral lines and electronic temperature T e of arc plasma were extracted to detect the change of arc length. The average T e signal in the period had a linear relationship with the arc length and was also quite sensitive to the collapse in welding seam caused by thermal accumulation. The average intensity of Ar I spectrum had better anti-jamming capability than T e , but was less sensitive than T e . Probably, analysis of these signals by synthesis could achieve a better effect on detecting the arc length.