Experimental and theoretical studies on keyhole dynamics in laser welding
- Osaka Univ. (Japan)
- Univ. of Tennessee Space Institute, Tullahoma, TN (United States)
The present paper describes the results of high speed photography, acoustic emission (AE) detection and plasma light emission (LE) measurement during CO{sub 2} laser welding of 304 stainless steel in different processing conditions. Video images with high spatial and temporal resolution allowed observation of the melt dynamics and keyhole evolution. The existence of a high speed melt flow which originated from the front part of weld pool and flowed along the sides wall of keyhole was confirmed by the slag motion on the weld pool. The characteristic frequencies of flow instability and keyhole fluctuations at different welding speed were measured and compared with the results of Fourier analyses of temporal AE and LE spectra. The experimental results were compared with the newly developed numerical model of keyhole dynamics. The model is based on the assumption that the propagation of front part of keyhole into material is due to the melt ejection driven by laser induced surface evaporation. The calculations predict that a high speed melt flow is induced at the front part of keyhole when the sample travel speed exceeds several 10 mm/s. The numerical analysis also shows the hump formation on the front keyhole wall surface. Experimentally observed melt behavior and transformation of the AE and LE spectra with variation of welding speed are qualitatively in good agreement with the model predictions.
- OSTI ID:
- 539298
- Report Number(s):
- CONF-961073--
- Country of Publication:
- United States
- Language:
- English
Similar Records
Effect of Laser-Matter Interaction on Molten Pool Flow and Keyhole Dynamics
Modeling of Keyhole-Induced Pore Formation in Laser-Arc Hybrid Welding of Aluminum Alloy with a Horizontal Fillet Joint