Study on the Relationship Between the Energy in Most Effective Frequency Range of Arc Sound Signal and the Change of Arc Height in Pulsed Al Alloy GTAW Process

Welding sound signal is mainly produced by the arc heat and the vibration of weld pool. In order to seek the relationship between characteristics in sound signal frequency and arc length variation, energy in every frequency band had been analysed, we found that arc sound signal distributed in every frequency band of 0–20 kHz, while arc length increasing, the energy of every frequency band increases, and the energy of 0–5000 Hz frequency band can generally reflect the increase and mutation of arc length, the differences when arc increase same value are similar. So linear fitting has been done to the original signal and the signal after 2 layer db3 wavelet denoising, conclusions can be made as that the average total energy of sound peak signal and the arc length have linear relationship, and 2 layer db3 wavelet denoising can make the error of linear relation smaller.