eprintid: 10169046
rev_number: 11
eprint_status: archive
userid: 699
dir: disk0/10/16/90/46
datestamp: 2023-04-28 10:37:34
lastmod: 2023-04-28 10:37:34
status_changed: 2023-04-28 10:37:34
type: article
metadata_visibility: show
sword_depositor: 699
creators_name: Guo, L
creators_name: Wang, H
creators_name: Liu, H
creators_name: Huang, Y
creators_name: Wei, Q
creators_name: Leung, CLA
creators_name: Wu, Y
creators_name: Wang, H
title: Quantifying the effects of gap on the molten pool and porosity formation in laser butt welding
ispublished: pub
divisions: UCL
divisions: B04
divisions: C05
divisions: F45
keywords: Simulation,
Laser butt welding,
Gap filling,
Bubble
note: This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions.
abstract: To obtain a better joint quality in butt welding of aluminum, the gap filling process and the quantification of the gap effects on the molten pool characteristic and the bubble formation were realized by a three-dimensional thermal-mechanistic-fluid coupled model, with the consideration of heat transfer, fluid flow, phase change and recoil pressure. The model was validated by the synchrotron-radiation result. The competition between the solidification and melting at the bottom of the molten pool was uncovered to determine the gap filling process and the molten pool morphology. Gap increased the heat loss, and the molten pool tip was elongated due to gap filling. Four phenomena appeared in sequence in the initial stage of butt welding: I. Gap filling; II. Frozen; III. Remelt; IV. Bubble formation. The result also demonstrated that the gap would disturb the molten pool. In the initial stable growth stage of the molten pool, the larger the gap width, the greater the molten pool depth. The sharp change of keyhole depth was due to the necking formation, while the small fluctuation of keyhole depth with larger gap values resulted from the perturbation by the gap. Bubble formation depends on the degree of the fluid flow and the gap filling due to the unique fluid dropping down phenomenon of butt welding with gap. A continuous melt pool cannot be formed when the gap width beyond 20 μm, which is detrimental to the welding quality. These findings are of great significance for guiding the optimization of butt-welding process, such as reducing the roughness of the butt interface or increasing the clamping force to reduce the butt gap.
date: 2023-08-01
date_type: published
publisher: Elsevier BV
official_url: https://doi.org/10.1016/j.ijheatmasstransfer.2023.124143
oa_status: green
full_text_type: other
language: eng
primo: open
primo_central: open_green
verified: verified_manual
elements_id: 2013796
doi: 10.1016/j.ijheatmasstransfer.2023.124143
lyricists_name: Leung, Chu Lun Alex
lyricists_id: CLALE63
actors_name: Leung, Chu Lun Alex
actors_id: CLALE63
actors_role: owner
full_text_status: public
publication: International Journal of Heat and Mass Transfer
volume: 209
article_number: 124143
issn: 0017-9310
citation:        Guo, L;    Wang, H;    Liu, H;    Huang, Y;    Wei, Q;    Leung, CLA;    Wu, Y;           Guo, L;  Wang, H;  Liu, H;  Huang, Y;  Wei, Q;  Leung, CLA;  Wu, Y;  Wang, H;   - view fewer <#>    (2023)    Quantifying the effects of gap on the molten pool and porosity formation in laser butt welding.                   International Journal of Heat and Mass Transfer , 209     , Article 124143.  10.1016/j.ijheatmasstransfer.2023.124143 <https://doi.org/10.1016/j.ijheatmasstransfer.2023.124143>.       Green open access   
 
document_url: https://discovery.ucl.ac.uk/id/eprint/10169046/3/Leung_Quantifying%20the%20effects%20of%20gap%20on%20the%20molten%20pool.pdf