Porosity formation and prevention in pulsed laser welding

Jun Zhou, Hai Lung Tsai

Research output: Contribution to journalArticle

60 Citations (Scopus)

Abstract

Porosity has been frequently observed in solidified, deep penetration pulsed laser welds. Porosity is detrimental to weld quality. Our previous study shows that porosity formation in laser welding is associated with the weld pool dynamics, keyhole collapse, and solidification processes. The objective of this paper is to use mathematical models to systematically investigate the transport phenomena leading to the formation of porosity and to find possible solutions to reduce or eliminate porosity formation in laser welding. The results indicate that the formation of porosity in pulsed laser weldihg is caused by two competing factors: one is the solidification rate of the molten metal and the other is the backfilling speed of the molten metal during the keyhole collapse process. Porosity will be formed in the final weld if the solidification rate of the molten metal exceeds the backfilling speed of liquid metal during the keyhole collapse and solidification processes. Porosity formation was found to be strongly related with the depth-to-width aspect ratio of the keyhole. The larger the ratio, the easier porosity will be formed, and the larger the size of the voids. Based on these studies, controlling the laser pulse profile is proposed to prevent/eliminate porosity formation in laser welding. Its effectiveness and limitations are demonstrated in the current studies. The model predictions are qualitatively consistent with reported experimental results.

Original languageEnglish (US)
Pages (from-to)1014-1024
Number of pages11
JournalJournal of Heat Transfer
Volume129
Issue number8
DOIs
StatePublished - Aug 1 2007

Fingerprint

laser welding
Laser beam welding
Pulsed lasers
pulsed lasers
Porosity
porosity
Liquid metals
solidification
Solidification
Welds
metals
liquid metals
aspect ratio
Aspect ratio
voids
Laser pulses
mathematical models
penetration
Mathematical models

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

Cite this

Zhou, Jun ; Tsai, Hai Lung. / Porosity formation and prevention in pulsed laser welding. In: Journal of Heat Transfer. 2007 ; Vol. 129, No. 8. pp. 1014-1024.
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Porosity formation and prevention in pulsed laser welding. / Zhou, Jun; Tsai, Hai Lung.

In: Journal of Heat Transfer, Vol. 129, No. 8, 01.08.2007, p. 1014-1024.

Research output: Contribution to journalArticle

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