Characterization of Metallurgical and Mechanical Properties of the Welded AISI 304L Using Pulsed and Non-Pulsed Current TIG Welding

Authors: A. A. Ugla

Abstract:

The present paper aims to investigate the effects of the welding process parameters and cooling state on the weld bead geometry, mechanical properties and microstructure characteristics for weldments of AISI 304L stainless steel. The welding process was carried out using TIG welding with pulsed/non-pulsed current techniques. The cooling state was introduced as an input parameter to investigate the main effects on the structure morphology and thereby the mechanical property. This paper clarifies microstructure- mechanical property relationship of the welded specimens. In this work, the selected pulse frequency levels were 5-500 Hz in order to study the effect of low and high frequencies on the weldment characteristics using filler metal of ER 308LSi. The key findings of this work clarified that the pulse frequency has a significant effect on the breaking of the dendrite arms during the welding process and so strongly influences on the tensile strength and microhardness. The cooling state also significantly affects on the microstructure texture and thereby, the mechanical properties. The most important factor affects the bead geometry and aspect ratio is the travel speed and pulse frequency.

Keywords: Microstructure, mechanical properties, pulse frequency, high pulse frequency, austenitic stainless steel, TIG welding.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1125479

References:

[1] K. D. Ramkumar, A. Choudhary, S. Aggarwal, and A. Srivastava, “A review on welding of AISI 304L austenitic stainless steel”,J. Manuf. Sci. Prod. Vol. 14, N. 1, 2014, pp 1-11.
[2] K. B. Hamjah, “Optimization of new semi-automatic TIG welding process for surface quality through Taguchi method,” PhD Thesis, University of Tun Hussein Onn, Malaysia, 2014.
[3] J. Mao, W. LÜ, L. Wang, D. Zhang, J. Qin, “Microstructure and mechanical properties of GTA weldments of titanium matrix composites prepared with or without current pulsing,” J. Trans. Nonferrous Met. Soc. China, vol. 24, 2014, pp. 1393-1399.
[4] A. Namjou, R. Dehmolaei, A. Sharafi, “A Comparative study,” in Magnetism, vol. III, on direct pulsed current gas tungsten arc welding of 25Cr-35Ni heat resistant steel,” Int. J. Natu. Eng. Sci., Vol. 8, N.11, 2014, pp. 22-28.
[5] M. Yousefieh, M. Shamanian, A. Saatchi, “Optimization of the pulsed current gas tungsten arc welding (PCGTAW) parameters for corrosion resistance of super duplex stainless steel (UNSS322760)welds using the Taguchi method,” J. Alloy Compd, vol 209, 2011, pp. 782-790.
[6] B. Balasubramanian, V. Jayabalan, V. Balasubramanian, “Optimizing the pulsed current gas tungsten arc welding parameters,” J. Mater. Sci. Technol., Vol. 22, N. 6, 2006, pp. 821-825.
[7] K. Pal, S.K. Pal, “Effect of pulse parameters on weld quality in pulsed gas metal welding: A review”, J. Mater. Eng. Perf. Vol. 20, N.6, 2011, pp. 918-931.
[8] K.H Tseng, C.P. Chou, “The effect of pulsed GTA welding on the residual stress of a stainless steel weldment”, J. mater. Proc. Technol. Vol. 123, N. 3, 2002, pp. 346-353.
[9] K. D. Ramkumar, A. Choudhary, S. Aggarwal, and A. Srivastava, “Characterization of microstructure and mechanical properties of continuous and pulsed current gas tungsten arc welded super austenitic stainless steel,” J. Mater. Res. Vol. 30 No. 10, 2015, pp. 1727-1746.
[10] K. S. Prasad, C. S. Rao, and D.N. Rao, “An investigation on weld quality characteristics of pulsed current micro plasma arc welded austenitic stainless steels,” Int. J. Eng. Sci. Technol. Vol. 4, No. 2, 2012, pp.159-168.
[11] R. Dinesh Kumar, S. Elangovan, and N. Siva Shanmugam, “Parametric optimization of pulsed-TIG welding process in butt joining of 304L austenitic stainless steel sheets,” Int. J. Res. Eng. Technol. Vol. 3, No. 11, 2014, pp. 213-219.
[12] C. Sadek, A. Alfaro, K.S. Chawla, J. Norrosh “Computer-based data acquisition for welding research and production” J. Mater. Proc. Technol., Vol. 53, 1995, pp. 1-13.
[13] Metals Handbook, (1973) Metallographic, structures, and phase diagrams. 8th Edition, American Society for Metals, Metal Park, Ohio 44073 USA.
[14] ASTM International. Standard test methods for tension testing of metallic materials (metric). Standard E8/E8M-09, ASTM International, W. Conshohocken, Pa, 2011.
[15] S. Kou (2003) Welding Metallurgy.2nd Edition, John Wiley &SONS, INC.
[16] P.K. Griridharan, N. Murugan, “Optimization of pulsed GTA welding process parameters for the welding of AISI 304Lstainless steel sheets”, Int. J Adv. Manu Technol., Vol.40, 2009, pp. 478-489. doi: 10.1007/s00170-008-1373-0.
[17] M. Arivarasu, K. Devendranath, N. Ramkumar Arivazhagan “Comparative studies of high and low frequency pulsing on the aspect ratio of weld bead in gas tungsten arc welded AISI 304L plates”, Procedia Engineering Vol.97, 2014, pp. 871-880.
[18] E. Farahani, M. Shamanian, F. Ashrafizadeh “A comparative study on direct and pulsed current gas tungsten arc welding of alloy 617”, Int J on Manuf and Material Science, Vol. 2, 2012, pp. 1-6. doi: 01IJMMMS.0201.41.
[19] A. Eghlimi, M. Shamanian, and K. Raeissi, “Dilution and ferrite number prediction in pulsed current cladding of super-duplex stainless steel using RSM,” J. Mater. Eng. Per., vol. 22, No. 12, 2013, pp. 3657-3664.
[20] A.H.I Mourad, A. Khourshid, and T. Sharif, “ Gas tungsten arc and laser beam welding processes effects on duplex stainless steel 2205 properties,” Mater. Sci. Eng. A, vol. 549, 2012, PP. 105-113.