Abstract: In order to solve the problem of welding bead subsidence in aluminum alloy welding process, which is caused by strong thermal accumulating effect and always leads to serious defects in welding bead, an arc sound sensing system is built up. The wavelet methods are used to analyze the relationship between welding arc sound and subsidence of aluminum alloy MIG welding bead. The experimental results show that there is an obvious relation between the energy of arc sound signal and welding subsidence. The total energy of arc sound signal increases with the degree of subsidence of welding bead. The changing rules of the arc sounds energies varied when it is analyzed in different frequency bands. The study provides a new effective method for real-time detecting the subsidence of welding bead in aluminum alloy MIG welding process.

Key words: Aluminum alloy, Arc sound, MIG welding, Wavelet analysis, Welding bead subsidence