Abstract
The objective of this paper was to study the laser spot welding process of low carbon steel sheet. The investigations were based on analytical and finite element analyses. The analytical analysis was focused on a consistent set of equations representing interaction of the laser beam with materials. The numerical analysis based on 3-D finite element analysis of heat flow during laser spot welding taken into account the temperature dependence of the physical properties and latent heat of transformations using ANSYS code V.10.0 to simulate the laser welding process. The effect of laser operating parameters on the results of the temperature profile were studied in addition to the effect on thermal stresses and dimensions of the laser welded workpiece which showed good correlations between analytical and numerical results. It was found that the temperature gradients during laser welding are usually very large and it was viewed that very high temperature at the center of the workpiece, and is decreased very significantly as propagating along the radial direction. Also it found that the thermal residual stresses around the laser spot due to plastic strains were very small and localized within 1.0 mm range. It is concluded that the laser welding process is effective to reduce the welding residual stress. The stresses along the lateral direction of the workpiece changed from compression at the spot under the laser beam and tension away from the spot at the end of welding to tension at the spot under the laser beam and compression away from the spot when it cooled, which are in a good agreement with the published results.
References
[2] J.R.Barber, 1984, "Thermoelastic displacements and stresses due to heat source moving over the surface of half plane," J. Appl. Mech., 51:636-340.
[3] N.Sumi, R.B.Hetnazske, and N.Noda, 1987, "Transient thermal stresses due to a local source of heat moving over the surface of an infinite slab," J. Therm. Stresses, 10:83-96.
[4] I.C.Sheng and Y.Chen, 1991, "Thermoelastic analysis for a semi-infinite plane subjected to a moving Gaussian heat source," J. Therm. Stresses, 14:129-141.
[5] M.Vicanek, A.Rosch, F.Piron, and G.Simon, 1994, "Thermal deformation of a solid surface under laser irradiation," Appl. Phys., 59:407-412.
[6] N.Postacioglu, P.Kapadia, and J.M.Dowdeu, 1997, "The thermal stress generated by a moving elliptical weld pool in the welding of thin metal sheets," Journal of Physics, D:Applied Physics, 30:2304-2312.
[7] Y.Dain, P.D, Kapadia, and J.M.Dowden, 1999, "The distortion gap width and stresses in laser welding of thin elastic plates," J. Phys. D:Appl. Phys., 32:168-175.
[8] L.J.Yang and Z.M.Xiao, 1995, "Elastic-Plastic modeling of the residual stress caused by welding," J. Materials Processings Technology, 84:589-601.
[9] S.Fujii, N.Takahashi, S.Sakai, T.Nakabayashi, and M.Muro, 2000, "Development of 2D simulation model for laser welding," Proc. SPIE, 3888:115-214.
[10] M.R.Frewin and D.A.Scott, 1999, "Finite element model of pulsed laser welding," welding J., 78:15-22.
[11] M.K.Apalak, K.Aldas, and F.Sen, 2003, "Thermal non-linear stresses in an adhesively bonded and laser spot welded single-lap joint during laser-metal interaction," J. Materials Processing Technology, 142:1-19.
[12] W.W.Duley, 1999, Laser Welding, Wiley, New York, NY.
[13] A.De, S.K.Maiti, C.A.Walash and H.K.D.H.Bhadeshia, 2003, "Finite element simulation of laser spot welding," Science and Technology of Welding and joining, Vol.8, No.5:377-384.
[14] B.S.Yilbas, S.A.Gbadebo, and M.Sami, 2000, "Laser heating: an electro-kinetic theory approach and induced thermal stresses," Optics and Laser Engineering, 33:65-79.
[15] S.A.Tsirkas, P.Papanikos, Th.Kermanidis, 2003, "Numerical simulation of the laser welding process in butt-joint specimens," Journal of Materials Processing Technology, 134:59-69.
[16] Nabeel K. Alsahib, Somer M. Nacy, Faiz F. Mustafa, 2008, “Spot welding residual stresses assessment using nonlinear numerical technique”, Journal of Eng., College of Eng., University of Baghdad, Vol.14, No.1:2202-2215.
Copyright: Open Access authors retain the copyrights of their papers, and all open access articles are distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution and reproduction in any medium, provided that the original work is properly cited. The use of general descriptive names, trade names, trademarks, and so forth in this publication, even if not specifically identified, does not imply that these names are not protected by the relevant laws and regulations. While the advice and information in this journal are believed to be true and accurate on the date of its going to press, neither the authors, the editors, nor the publisher can accept any legal responsibility for any errors or omissions that may be made. The publisher makes no warranty, express or implied, with respect to the material contained herein.