Product Code: ICAL09_1502

Acoustic Monitoring of Weld Penetration during Laser Welding of High Strength Steels
Authors:
Wei Huang, southern methodist university; dallas TX USA
Radovan Kovacevic, Southern Methodist University; Dallas TX USA
Presented at ICALEO 2009

High-strength steels are being found of great applications in different industries because of their high strength-to-weight ratio. In order to achieve a high quality weld with full weld penetration during the laser welding process of the high strength steel, acoustic monitoring based on a microphone is applied to sense the weld penetration in this study. To overcome the obstacle posed by intensive background noise, a noise reduction method called spectral subtraction is used to maximally denoise the acquired acoustic signals. Based on these denoised signals from the full weld penetration and partial weld penetration, the analyses in the time domain and frequency domain are carried out. The results indicate that the full weld penetration produces a higher sound pressure than the partial weld penetration and the corresponding acoustic signals have different frequency distributions from 500 Hz to 1500 Hz. Based on these differences, two acoustic signatures are extracted from the denoised signals and used to characterize the depth of weld penetration and help understand the internal mechanism of the laser-material interaction.