Asian Journal of Engineering and Applied Technology (AJEAT)
Study of Microstructure 304L Austenitic Stainless Steel Weld Deposited by GTAW for Root Pass and SMAW for Filler Passes
Author : Harsimranjit Singh Randhawa and Sunil KumarVolume 7 No.2 July-December 2018 pp 21-25
Abstract
In the present experimentation, a 10mm thick austenitic stainless steel plate type 304L is welded using single V-joint configuration and approaching the joint from one side. Back purging has been employed to protect the rear side of the root pass weld metal against oxidation. The root pass has been deposited by gas tungsten arc welding (GTAW) process. The filler passes are deposited by shielding metal arc welding (SMAW) process at 90A and 120A welding currents giving heat inputs of the order of 0.679 and 0.933 kJ/mm respectively while the speed of weld deposition was kept practically constant. The results of experimentation show that the micro-hardness of weld metal and heat affected zone (HAZ) of weldments produced at lower heat input is higher whereas impact toughness value of weld metal and HAZ is lower than that of joints produced at higher heat input. The microstructure of weld metal and heat affected zone developed at lower weld heat input has been observed finer in comparison to that resulted at higher heat input. This has primarily happened due to a higher rate of cooling at low heat input.
Keywords
Austenitic stainless steel 304L, GTAW, SMAW, weld heat input, back purging, weldment
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References
[1] American Society for Testing and Materials ASTM E8-15, “Standard Test Methods for Tension Testing of Metallic Materials”.
[2] American Society for Testing and Materials ASTM E23-12, “Standard Test Methods for Notched Bar Impact Testing of Metallic Materials”.
[3] American Society for testing and Materials ASTM E290-14, “Standard Test Methods for Bend Testing of Material for Ductility”.
[4] A.Choubey and V.S.Jatti, “Influence of heat input on mechanical properties and microstructure of austenitic 202 grade stainless steel weldments”, World Scientific and Engineering Academy and Society, Vol. 9, pp. 222-228, 2014.
[5] S.A. David, J.M. Vitek and D.J. Alexander, “Embrittlement of austenitic stainless steel welds”, Scientific and Technical Information, Vol. 5, pp. 1-8, 1995.
[6] P.S. Korinko and S.H. Malene, “Consideration for the weldability of types 304L and 316L stainless steel”, International American Society for Metals, Vol. 1, No. 4, pp. 61-68, 2001.
[7] K. Liu, Y. Li and J. Wang, “Microstructure and low temperature mechanical properties of 304 stainless steel joints by PAW+GTAW combined welding”, Journal of Material Engineering and Performance, Vol. 25, pp. 4561-4573, 2016.
[8] C.E. Lyman, “Analytical electron microscopy of stainless steel weld metal on cooling, type 304L stainless steel weld metal transforms from delta ferrite to austenite by a massive transformation”, The American Welding Society and the Welding Research Council, Vol. 34, pp.189-194, 1979.
[9] S. Nasser, W. Guo and D. P. Kihl, “Thermo-mechanical response of AL-6XN stainless steel over a wide range of strain rates and temperatures”, Journal of the Mechanics and Physics of Solids, 49, pp.1823-1846, 2001. [10] “Properties and Selection: Irons, Steels, and High Performance Alloys”, ASM Handbook, International American Society for Metals, 10th Ed., Vol. 1, pp.1394-1395, 1990.
[11] T.A. Tabish, T. Abbas, M. Farhan, S. Atiq and T.Z. Butt, “Effect of heat input on microstructure and mechanical properties of the TIG welded joints of AISI 304 stainless steel”, International Journal of Scientific and Engineering Research, Vol. 5, pp. 1532-1541, 2014.