Flow and bead formation characteristics in high power laser welding at different welding positions

Suck-Joo Na, Sang-Woo Han, Muhammad Sohail, Linjie Zhang, Andrey Gumenyuk, Michael Rethmeier, Miikka Karhu, Veli Kujanpää

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientific

Abstract

The numerical simulations of high power laser keyhole welding at different welding positions are performed by using Volume-Of-Fluid (VOF) method. The main material is SS400. The multi-physics phenomenon is considered using several models, such as the heat flux of Gaussian heat source, the recoil pressure with Clausisus-Clapeyron equation, the Marangoni flow considering temperature gradient, the buoyancy force with Boussinesq approximation, the additional shear stress and heat source due to metallic vapor ejected through keyhole entrance, the bubble formation assumed as adiabatic bubble, and the multiple-reflection by solving proper discriminant, are used. To analyze the fluid flow pattern, the concept of streamline formed by reconstructing the value of the velocity vector is applied. Partial and full penetration cases at different welding positions are considered. The welding position seems to have only a minor influence on bead formation characteristics in both cases. This is probably due to the fact that the recoil pressure has a major influence when compared to other driving forces. The flow characteristics and fluid velocity in weld pool are analyzed to compare the gravity direction effect at different welding positions. It is observed that the clockwise flow pattern is mainly formed by the recoil pressure on the keyhole surface in the case of partial penetration. The laser energy can't maintain the whole weld pool when the weld pool size becomes too large. And then the solidification starts from the middle part of weld pool and a necked weld pool shape is formed. In the full penetration welding, the weld pool flow patterns are affected by the leakage of laser power through the full penetration keyhole and also by surface tension. Furthermore, the numerical simulation of full penetration welding with AISI316L is also performed to analyze the effect of material properties. The weld bead shapes obtained by simulations were compared with the corresponding experimental results to confirm the validity of the process models adopted and the CFD simulation tool.
Original languageEnglish
Title of host publicationProceedings of the Lasers in Manufacturing Conference 2015
Number of pages6
Publication statusPublished - 2015
MoE publication typeB3 Non-refereed article in conference proceedings
EventLasers in Manufacturing 2015, LiM 2015 - Munich, Germany
Duration: 22 Jun 201525 Jun 2015

Conference

ConferenceLasers in Manufacturing 2015, LiM 2015
Abbreviated titleLiM 2015
CountryGermany
CityMunich
Period22/06/1525/06/15

Fingerprint

Laser beam welding
High power lasers
Welding
Welds
Flow patterns
Bubble formation
Fluids
Lasers
Computer simulation
Buoyancy
Bubbles (in fluids)
Thermal gradients
Surface tension
Solidification
Heat flux
Shear stress
Flow of fluids
Materials properties
Gravitation
Computational fluid dynamics

Keywords

  • macro processing (joining, welding)
  • high power laser keyhole welding
  • numerical simulation
  • different welding position
  • flow pattern
  • weld pool

Cite this

Na, S-J., Han, S-W., Sohail, M., Zhang, L., Gumenyuk, A., Rethmeier, M., ... Kujanpää, V. (2015). Flow and bead formation characteristics in high power laser welding at different welding positions. In Proceedings of the Lasers in Manufacturing Conference 2015
Na, Suck-Joo ; Han, Sang-Woo ; Sohail, Muhammad ; Zhang, Linjie ; Gumenyuk, Andrey ; Rethmeier, Michael ; Karhu, Miikka ; Kujanpää, Veli. / Flow and bead formation characteristics in high power laser welding at different welding positions. Proceedings of the Lasers in Manufacturing Conference 2015. 2015.
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title = "Flow and bead formation characteristics in high power laser welding at different welding positions",
abstract = "The numerical simulations of high power laser keyhole welding at different welding positions are performed by using Volume-Of-Fluid (VOF) method. The main material is SS400. The multi-physics phenomenon is considered using several models, such as the heat flux of Gaussian heat source, the recoil pressure with Clausisus-Clapeyron equation, the Marangoni flow considering temperature gradient, the buoyancy force with Boussinesq approximation, the additional shear stress and heat source due to metallic vapor ejected through keyhole entrance, the bubble formation assumed as adiabatic bubble, and the multiple-reflection by solving proper discriminant, are used. To analyze the fluid flow pattern, the concept of streamline formed by reconstructing the value of the velocity vector is applied. Partial and full penetration cases at different welding positions are considered. The welding position seems to have only a minor influence on bead formation characteristics in both cases. This is probably due to the fact that the recoil pressure has a major influence when compared to other driving forces. The flow characteristics and fluid velocity in weld pool are analyzed to compare the gravity direction effect at different welding positions. It is observed that the clockwise flow pattern is mainly formed by the recoil pressure on the keyhole surface in the case of partial penetration. The laser energy can't maintain the whole weld pool when the weld pool size becomes too large. And then the solidification starts from the middle part of weld pool and a necked weld pool shape is formed. In the full penetration welding, the weld pool flow patterns are affected by the leakage of laser power through the full penetration keyhole and also by surface tension. Furthermore, the numerical simulation of full penetration welding with AISI316L is also performed to analyze the effect of material properties. The weld bead shapes obtained by simulations were compared with the corresponding experimental results to confirm the validity of the process models adopted and the CFD simulation tool.",
keywords = "macro processing (joining, welding), high power laser keyhole welding, numerical simulation, different welding position, flow pattern, weld pool",
author = "Suck-Joo Na and Sang-Woo Han and Muhammad Sohail and Linjie Zhang and Andrey Gumenyuk and Michael Rethmeier and Miikka Karhu and Veli Kujanp{\"a}{\"a}",
note = "Invited talk Project : 100976",
year = "2015",
language = "English",
booktitle = "Proceedings of the Lasers in Manufacturing Conference 2015",

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Na, S-J, Han, S-W, Sohail, M, Zhang, L, Gumenyuk, A, Rethmeier, M, Karhu, M & Kujanpää, V 2015, Flow and bead formation characteristics in high power laser welding at different welding positions. in Proceedings of the Lasers in Manufacturing Conference 2015. Lasers in Manufacturing 2015, LiM 2015, Munich, Germany, 22/06/15.

Flow and bead formation characteristics in high power laser welding at different welding positions. / Na, Suck-Joo; Han, Sang-Woo; Sohail, Muhammad; Zhang, Linjie; Gumenyuk, Andrey; Rethmeier, Michael; Karhu, Miikka; Kujanpää, Veli.

Proceedings of the Lasers in Manufacturing Conference 2015. 2015.

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientific

TY - GEN

T1 - Flow and bead formation characteristics in high power laser welding at different welding positions

AU - Na, Suck-Joo

AU - Han, Sang-Woo

AU - Sohail, Muhammad

AU - Zhang, Linjie

AU - Gumenyuk, Andrey

AU - Rethmeier, Michael

AU - Karhu, Miikka

AU - Kujanpää, Veli

N1 - Invited talk Project : 100976

PY - 2015

Y1 - 2015

N2 - The numerical simulations of high power laser keyhole welding at different welding positions are performed by using Volume-Of-Fluid (VOF) method. The main material is SS400. The multi-physics phenomenon is considered using several models, such as the heat flux of Gaussian heat source, the recoil pressure with Clausisus-Clapeyron equation, the Marangoni flow considering temperature gradient, the buoyancy force with Boussinesq approximation, the additional shear stress and heat source due to metallic vapor ejected through keyhole entrance, the bubble formation assumed as adiabatic bubble, and the multiple-reflection by solving proper discriminant, are used. To analyze the fluid flow pattern, the concept of streamline formed by reconstructing the value of the velocity vector is applied. Partial and full penetration cases at different welding positions are considered. The welding position seems to have only a minor influence on bead formation characteristics in both cases. This is probably due to the fact that the recoil pressure has a major influence when compared to other driving forces. The flow characteristics and fluid velocity in weld pool are analyzed to compare the gravity direction effect at different welding positions. It is observed that the clockwise flow pattern is mainly formed by the recoil pressure on the keyhole surface in the case of partial penetration. The laser energy can't maintain the whole weld pool when the weld pool size becomes too large. And then the solidification starts from the middle part of weld pool and a necked weld pool shape is formed. In the full penetration welding, the weld pool flow patterns are affected by the leakage of laser power through the full penetration keyhole and also by surface tension. Furthermore, the numerical simulation of full penetration welding with AISI316L is also performed to analyze the effect of material properties. The weld bead shapes obtained by simulations were compared with the corresponding experimental results to confirm the validity of the process models adopted and the CFD simulation tool.

AB - The numerical simulations of high power laser keyhole welding at different welding positions are performed by using Volume-Of-Fluid (VOF) method. The main material is SS400. The multi-physics phenomenon is considered using several models, such as the heat flux of Gaussian heat source, the recoil pressure with Clausisus-Clapeyron equation, the Marangoni flow considering temperature gradient, the buoyancy force with Boussinesq approximation, the additional shear stress and heat source due to metallic vapor ejected through keyhole entrance, the bubble formation assumed as adiabatic bubble, and the multiple-reflection by solving proper discriminant, are used. To analyze the fluid flow pattern, the concept of streamline formed by reconstructing the value of the velocity vector is applied. Partial and full penetration cases at different welding positions are considered. The welding position seems to have only a minor influence on bead formation characteristics in both cases. This is probably due to the fact that the recoil pressure has a major influence when compared to other driving forces. The flow characteristics and fluid velocity in weld pool are analyzed to compare the gravity direction effect at different welding positions. It is observed that the clockwise flow pattern is mainly formed by the recoil pressure on the keyhole surface in the case of partial penetration. The laser energy can't maintain the whole weld pool when the weld pool size becomes too large. And then the solidification starts from the middle part of weld pool and a necked weld pool shape is formed. In the full penetration welding, the weld pool flow patterns are affected by the leakage of laser power through the full penetration keyhole and also by surface tension. Furthermore, the numerical simulation of full penetration welding with AISI316L is also performed to analyze the effect of material properties. The weld bead shapes obtained by simulations were compared with the corresponding experimental results to confirm the validity of the process models adopted and the CFD simulation tool.

KW - macro processing (joining, welding)

KW - high power laser keyhole welding

KW - numerical simulation

KW - different welding position

KW - flow pattern

KW - weld pool

M3 - Conference article in proceedings

BT - Proceedings of the Lasers in Manufacturing Conference 2015

ER -

Na S-J, Han S-W, Sohail M, Zhang L, Gumenyuk A, Rethmeier M et al. Flow and bead formation characteristics in high power laser welding at different welding positions. In Proceedings of the Lasers in Manufacturing Conference 2015. 2015