Transport phenomena and the associated humping formation in laser welding

Jun Zhou, H. L. Tsai, P. C. Wang

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Scopus citations

Abstract

Humping is a frequently observed welding defect in laser welding which is caused when the welding speed exceeds a certain limit while the other welding conditions remain unchanged. Humping is characterized by the appearance of unsmooth and discontinuity of humps at the surface of the weld. The formation of humping is generally understood to be caused by the complex heat transfer and melt flow in a high speed welding process. However, so far the fundamental mechanisms causing humping are not fully understood, and research on determining the onset of humping has been based on the "trial-and-error" procedure. In this paper, mathematical models previously developed by the authors for the transport phenomena in laser welding have been extended to investigate the formation of the humping defect. In this study, the transient heat transfer and melt flow in the weld pool during the keyhole formation and collapse, and melt solidification are calculated for a 3-D moving laser welding. Different humping patterns have been predicted by the present study in different laser power levels and welding speeds. From the present study, it was found that the formation of humping in laser welding is caused by the interplay between two important factors: a) the strong liquid metal flow in the real part of the keyhole induced mainly by the laser recoil pressure and b) the rapid solidification rate of the liquid metal. The humping pattern can be well explained by the calculated melt flow and the solidification process.

Original languageEnglish (US)
Title of host publicationProceedings of the ASME Heat Transfer Division 2005
Pages945-953
Number of pages9
Edition2
DOIs
Publication statusPublished - Dec 1 2005
Event2005 ASME International Mechanical Engineering Congress and Exposition, IMECE 2005 - Orlando, FL, United States
Duration: Nov 5 2005Nov 11 2005

Publication series

NameAmerican Society of Mechanical Engineers, Heat Transfer Division, (Publication) HTD
Number2
Volume376 HTD
ISSN (Print)0272-5673

Other

Other2005 ASME International Mechanical Engineering Congress and Exposition, IMECE 2005
CountryUnited States
CityOrlando, FL
Period11/5/0511/11/05

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All Science Journal Classification (ASJC) codes

  • Mechanical Engineering
  • Fluid Flow and Transfer Processes

Cite this

Zhou, J., Tsai, H. L., & Wang, P. C. (2005). Transport phenomena and the associated humping formation in laser welding. In Proceedings of the ASME Heat Transfer Division 2005 (2 ed., pp. 945-953). (American Society of Mechanical Engineers, Heat Transfer Division, (Publication) HTD; Vol. 376 HTD, No. 2). https://doi.org/10.1115/IMECE2005-81766