Heat transfer and fluid flow during keyhole mode laser welding of tantalum, Ti-6Al-4V, 304L stainless steel and vanadium

R. Rai, J. W. Elmer, Todd Palmer, Tarasankar Debroy

Research output: Contribution to journalArticle

183 Citations (Scopus)

Abstract

Because of the complexity of several simultaneous physical processes, most heat transfer models of keyhole mode laser welding require some simplifications to make the calculations tractable. The simplifications often limit the applicability of each model to the specific materials systems for which the model is developed. In this work, a rigorous, yet computationally efficient, keyhole model is developed and tested on tantalum, Ti-6Al-4V, 304L stainless steel and vanadium. Unlike previous models, this one combines an existing model to calculate keyhole shape and size with numerical fluid flow and heat transfer calculations in the weld pool. The calculations of the keyhole profile involved a point-by-point heat balance at the keyhole walls considering multiple reflections of the laser beam in the vapour cavity. The equations of conservation of mass, momentum and energy are then solved in three dimensions assuming that the temperatures at the keyhole wall reach the boiling point of the different metals or alloys. A turbulence model based on Prandtl's mixing length hypothesis was used to estimate the effective viscosity and thermal conductivity in the liquid region. The calculated weld cross-sections agreed well with the experimental results for each metal and alloy system examined here. In each case, the weld pool geometry was affected by the thermal diffusivity, absorption coefficient, and the melting and boiling points, among the various physical properties of the alloy. The model was also used to better understand solidification phenomena and calculate the solidification parameters at the trailing edge of the weld pool. These calculations indicate that the solidification structure became less dendritic and coarser with decreasing weld velocities over the range of speeds investigated in this study. Overall, the keyhole weld model provides satisfactory simulations of the weld geometries and solidification sub-structures for diverse engineering metals and alloys.

Original languageEnglish (US)
Article number037
Pages (from-to)5753-5766
Number of pages14
JournalJournal of Physics D: Applied Physics
Volume40
Issue number18
DOIs
StatePublished - Sep 21 2007

Fingerprint

Tantalum
Vanadium
laser welding
Laser beam welding
Stainless Steel
Laser modes
tantalum
vanadium
fluid flow
Flow of fluids
stainless steels
Stainless steel
heat transfer
Welds
Heat transfer
solidification
Solidification
Metals
Boiling point
simplification

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Acoustics and Ultrasonics
  • Surfaces, Coatings and Films

Cite this

@article{7638870075e84f1aa7279d6eb7e276ea,
title = "Heat transfer and fluid flow during keyhole mode laser welding of tantalum, Ti-6Al-4V, 304L stainless steel and vanadium",
abstract = "Because of the complexity of several simultaneous physical processes, most heat transfer models of keyhole mode laser welding require some simplifications to make the calculations tractable. The simplifications often limit the applicability of each model to the specific materials systems for which the model is developed. In this work, a rigorous, yet computationally efficient, keyhole model is developed and tested on tantalum, Ti-6Al-4V, 304L stainless steel and vanadium. Unlike previous models, this one combines an existing model to calculate keyhole shape and size with numerical fluid flow and heat transfer calculations in the weld pool. The calculations of the keyhole profile involved a point-by-point heat balance at the keyhole walls considering multiple reflections of the laser beam in the vapour cavity. The equations of conservation of mass, momentum and energy are then solved in three dimensions assuming that the temperatures at the keyhole wall reach the boiling point of the different metals or alloys. A turbulence model based on Prandtl's mixing length hypothesis was used to estimate the effective viscosity and thermal conductivity in the liquid region. The calculated weld cross-sections agreed well with the experimental results for each metal and alloy system examined here. In each case, the weld pool geometry was affected by the thermal diffusivity, absorption coefficient, and the melting and boiling points, among the various physical properties of the alloy. The model was also used to better understand solidification phenomena and calculate the solidification parameters at the trailing edge of the weld pool. These calculations indicate that the solidification structure became less dendritic and coarser with decreasing weld velocities over the range of speeds investigated in this study. Overall, the keyhole weld model provides satisfactory simulations of the weld geometries and solidification sub-structures for diverse engineering metals and alloys.",
author = "R. Rai and Elmer, {J. W.} and Todd Palmer and Tarasankar Debroy",
year = "2007",
month = "9",
day = "21",
doi = "10.1088/0022-3727/40/18/037",
language = "English (US)",
volume = "40",
pages = "5753--5766",
journal = "Journal Physics D: Applied Physics",
issn = "0022-3727",
publisher = "IOP Publishing Ltd.",
number = "18",

}

Heat transfer and fluid flow during keyhole mode laser welding of tantalum, Ti-6Al-4V, 304L stainless steel and vanadium. / Rai, R.; Elmer, J. W.; Palmer, Todd; Debroy, Tarasankar.

In: Journal of Physics D: Applied Physics, Vol. 40, No. 18, 037, 21.09.2007, p. 5753-5766.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Heat transfer and fluid flow during keyhole mode laser welding of tantalum, Ti-6Al-4V, 304L stainless steel and vanadium

AU - Rai, R.

AU - Elmer, J. W.

AU - Palmer, Todd

AU - Debroy, Tarasankar

PY - 2007/9/21

Y1 - 2007/9/21

N2 - Because of the complexity of several simultaneous physical processes, most heat transfer models of keyhole mode laser welding require some simplifications to make the calculations tractable. The simplifications often limit the applicability of each model to the specific materials systems for which the model is developed. In this work, a rigorous, yet computationally efficient, keyhole model is developed and tested on tantalum, Ti-6Al-4V, 304L stainless steel and vanadium. Unlike previous models, this one combines an existing model to calculate keyhole shape and size with numerical fluid flow and heat transfer calculations in the weld pool. The calculations of the keyhole profile involved a point-by-point heat balance at the keyhole walls considering multiple reflections of the laser beam in the vapour cavity. The equations of conservation of mass, momentum and energy are then solved in three dimensions assuming that the temperatures at the keyhole wall reach the boiling point of the different metals or alloys. A turbulence model based on Prandtl's mixing length hypothesis was used to estimate the effective viscosity and thermal conductivity in the liquid region. The calculated weld cross-sections agreed well with the experimental results for each metal and alloy system examined here. In each case, the weld pool geometry was affected by the thermal diffusivity, absorption coefficient, and the melting and boiling points, among the various physical properties of the alloy. The model was also used to better understand solidification phenomena and calculate the solidification parameters at the trailing edge of the weld pool. These calculations indicate that the solidification structure became less dendritic and coarser with decreasing weld velocities over the range of speeds investigated in this study. Overall, the keyhole weld model provides satisfactory simulations of the weld geometries and solidification sub-structures for diverse engineering metals and alloys.

AB - Because of the complexity of several simultaneous physical processes, most heat transfer models of keyhole mode laser welding require some simplifications to make the calculations tractable. The simplifications often limit the applicability of each model to the specific materials systems for which the model is developed. In this work, a rigorous, yet computationally efficient, keyhole model is developed and tested on tantalum, Ti-6Al-4V, 304L stainless steel and vanadium. Unlike previous models, this one combines an existing model to calculate keyhole shape and size with numerical fluid flow and heat transfer calculations in the weld pool. The calculations of the keyhole profile involved a point-by-point heat balance at the keyhole walls considering multiple reflections of the laser beam in the vapour cavity. The equations of conservation of mass, momentum and energy are then solved in three dimensions assuming that the temperatures at the keyhole wall reach the boiling point of the different metals or alloys. A turbulence model based on Prandtl's mixing length hypothesis was used to estimate the effective viscosity and thermal conductivity in the liquid region. The calculated weld cross-sections agreed well with the experimental results for each metal and alloy system examined here. In each case, the weld pool geometry was affected by the thermal diffusivity, absorption coefficient, and the melting and boiling points, among the various physical properties of the alloy. The model was also used to better understand solidification phenomena and calculate the solidification parameters at the trailing edge of the weld pool. These calculations indicate that the solidification structure became less dendritic and coarser with decreasing weld velocities over the range of speeds investigated in this study. Overall, the keyhole weld model provides satisfactory simulations of the weld geometries and solidification sub-structures for diverse engineering metals and alloys.

UR - http://www.scopus.com/inward/record.url?scp=34548429692&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=34548429692&partnerID=8YFLogxK

U2 - 10.1088/0022-3727/40/18/037

DO - 10.1088/0022-3727/40/18/037

M3 - Article

AN - SCOPUS:34548429692

VL - 40

SP - 5753

EP - 5766

JO - Journal Physics D: Applied Physics

JF - Journal Physics D: Applied Physics

SN - 0022-3727

IS - 18

M1 - 037

ER -