Study of Residual Stress Surface Distribution on Laser Welded Steel Sheets

Abstract:

Advent of high power diode laser has substantially contributed to the popularity of laser welding in industry where its virtues such as low heat input and good weld strength are highly appreciated. However, one of the drawbacks of the laser welding is distortion of the welded bodies that is closely linked with the generation and/or redistribution of residual stresses in the vicinity of the weld. In this contribution, mapping of surface macroscopic residual stresses in two directions, i.e. parallel and perpendicular to the welds, were performed for two bodies. The first contained a weld created with the high power diode laser beam speed of 2 m/min and the second with the speed of 15 m/min. Our aim was to compare not only resulting fields of residual stresses, but also to perform qualitative assessment of the possible presence of crystallographic texture and gain a qualitative apprehension about the grain sizes in the vicinity of a laser weld joining two steel sheets. Larger distortion of the body with a laser weld is exhibited by the sample manufactured with approximately 8 times bigger speed of laser beam. This sample is in the immediate vicinity characterized by substantial compressive residual stresses in the direction perpendicular to the weld.

• Periodical: Applied Mechanics and Materials (Volume 486)
• Pages: 3-8
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.486.3
• Online since: December 2013
• Authors: Zdenek Pala*, Kamil Kolařík, Nikolaj Ganev, Jiří Čapek
• Keywords: Laser Welding, Residual Stress, X-Ray Diffraction (XRD)

References

[1] L. Li, The advances and characteristics of high-power diode laser materials processing, Optics and Lasers in Engineering 34 (2000) 231-253.

DOI: 10.1016/s0143-8166(00)00066-x

[2] J. Lawrence, L. Li, Wettability characteristics of an Al2O3/SiO2-based ceramic modified with CO2, Nd: YAG, excimer and high-power diode lasers, J Phys D 32 (1999) 1075-1082.

DOI: 10.2351/1.5059134

[3] A.G. Olabi, K.Y. Benyounis, M.S.J. Hashmi, Application of Response Surface Methodology in Describing the Residual Stress Distribution in CO2 Laser Welding of AISI304, Strain 43 (2007) 37-46.

DOI: 10.1111/j.1475-1305.2007.00305.x

[4] I. Kraus, N. Ganev, Residual Stress and Stress Gradients, Industrial Applications of X-Ray Diffraction, Marcel Dekker, New York, 2000, pp.793-811.

[5] J. M. Leoni, P. Scardi, S. Rossi, L. Fedrizzi, Y. Massiani, (Ti, Cr) N and Ti/TiN PVD coatings on 304 stainless steel substrates: Texture and residual stress, Thin Solid Films 345 (2), 263-269.

DOI: 10.1016/s0040-6090(98)01741-6

[6] Macherauch E., Müller P.: Das sin2y -Verfahren der röntgenographischen Spannungsmessung, Zeitschrift für angewandte Physik 13 (1961) 33 – 38.

[7] R.A. Winholtz, J.B. Cohen, Generalised Least-squares Determination of Triaxial Stress States by X-ray Diffraction and the Associated Erors, Aust. J. Phys. 41 (1988) 189-199.

DOI: 10.1071/ph880189

[8] W.A. Rachinger, A Correction for the α1 α2 Doublet in the Measurement of Widths of X-ray Diffraction Lines, J. Sci. Instrum. 25 (1948) 254 - 259.

DOI: 10.1088/0950-7671/25/7/125

[9] J.D. Eshelby, The Determination of the Elastic Field of an Ellipsoidal Inclusion, and Related Problems, Proc. Roy. Soc. A 241 (1957) 376 – 396.