Affiliation:
1. Taiyuan University of Science and Technology
Abstract
Porosity is formed because of the keyhole collapse. The porosity formation is associated with the melt pool dynamics, the keyhole collapse and solidification processes. The objective of the paper is t to investigate porosity formation mechanisms and fluid flow in the melt pool using the volume of fluid method. The results indicate that the formation of porosity in continuous wave keyhole mode laser welding is associated to keyhole collapse, backfilling of liquid metal close the gas exit of the laser welding keyhole, surface tension of the gas/liquid interface play an important role in the backfilling downward to the keyhole right after laser beams left.Keywords: porosity; keyhole; collapse; welding; model
Publisher
Trans Tech Publications, Ltd.
Reference8 articles.
1. M. H. Cho, D.F. Farson, Laser weld keyhole dynamics and control, http: /www. aws. org/conferences/abstracts/2003/03b. pdf.
2. Ishide, T., Tsubota, S., Nayama, M., Shimokusu, 10 kW class YAG laser application for heavy components, " SPIE, High-power lasers in manufacturing, Osaka, 3888(1999)543–550.
3. Norris J. T., Robino C. V., Hirschfeld D. A., Effects of laser parameters on porosity formation: Investigating millimeter scale continuous wave Nd: YAG welds, Welding Journal, 90(2011)198s-203s.
4. Jun Zhou, Hai-Lung Tsai, Porosity formation and prevention in pulsed laser welding, Transactions of the ASME, 129(2007) 1014-1024.
5. Kawaguchi I., Tsukamoto S., Arakane G. and. Honda H, Characteristics of high power CO2 laser welding and porosity suppression mechanism by nitrogen shield - Study on high power laser welding phenomena- (report 1), Yosetsu Gakkai Ronbunshu/Quarterly Journal of the Japan Welding Society, 23(2), (2005).