Effect of Post-Weld Intercritical Annealing on the Microstructure and Tensile Properties of a Gas Tungsten Arc Welded DP700 Steel

Subject Areas : Welding

Hamid Ashrafi ¹ , Sayyed Erfan Aghili ²

1 - Faculty of Chemical and Materials Engineering, Shahrood University of Technology, Shahrood, 3619995161, Iran
2 - Materials Engineering Group, Golpayegan College of Engineering, Isfahan University of Technology, Golpayegan 87717-67498, Iran.

Received: 2021-08-02 Accepted : 2021-10-13 Published : 2021-11-01

Keywords: Tensile strength, welding, Dual Phase Steel, intercritical annealing,

Abstract :

The aim of this study was to investigate the effect of post-weld intercritical annealing (IA) on the microstructure and tensile properties of a gas tungsten arc-welded DP700 steel sheet. In this regard, DP700 steel sheets were first joined using gas-tungsten arc welding. The welded sheet was then annealed at intercritical temperature of 720 °C for 120 s followed by water quenching. Microstructure and microhardness of the as-welded and post-weld heat-treated samples were characterized, as well as tensile properties. Results showed that the microstructure varied from ferrite-tempered martensite in the subcritical heat affected zone to a mixture of bainite, Widmanestatten ferrite, ferrite-carbide aggregate and grain boundary ferrite in the fusion zone. This heterogeneity in the microstructure led to the formation of hardened and softened zones across the welded joint. Strain localization in the softened zone during tensile testing resulted in a joint efficiency of ~ 81% and early fracture. After post weld IA, dual phase microstructures comprising of ferrite and martensite, with different sizes and morphologies, were formed across the welded joint. This new microstructure resulted in the elimination of hardened and softened zones, which in turn led to high joint efficiency of ~ 98%.

References:

References

[1] S. Nikkhah, H. Mirzadeh, M. Zamani, "Fine tuning the mechanical properties of dual phase steel via thermomechanical processing of cold rolling and intercritical annealing", Mater. Chem. Phys., Vol. 230,  2019, pp. 1-8.

[2] H. Ashrafi, M. Shamanian, R. Emadi, M. Sanayei, F. Farhadi, J.A. Szpunar, "Characterization of microstructure and microtexture in a cold-rolled and intercritically annealed dual-phase steel", J. Mater. Eng. Perform., Vol 30,  2021, pp 7306–7313.

[3] A.K. Srivastava, N.K. Patel, B.R. Kumar, A. Sharma, B. Ahn, "Strength–ductility trade-off in dual-phase steel tailored via controlled phase transformation", J. Mater. Eng. Perform., Vol. 29,   2020, pp. 2783–2791.

[4] M. Maleki, H. Mirzadeh, M. Zamani, "Effect of intercritical annealing on mechanical properties and work-hardening response of high formability dual phase steel", Steel Res. Intl., Vol 89,  2017, pp. 1700412.

[5] S. Pandre, P. Takalkar, N. Kotkunde, S.K. Singh, A.U. Haq, "Influence of temperatures and strain rates on tensile deformation behaviour of dp 590 steel", Materials Today: Proceedings, Vol. 18,   2019, pp. 2603–2610.

[6] H. Zhang, X. Qiu, Y. Bai, F. Xing, H. Yu, Y. Shi, "Resistance spot welding macro characteristics of the dissimilar thickness dual phase steels", Mater. Des., Vol. 63, 2014, pp. 151-158.

[7] F. Hayat, I. Sevim, "The effect of welding parameters on fracture toughness of resistance spot-welded galvanized DP600 automotive steel sheets", Int. J. Adv. Manuf. Technol., Vol. 58, 2012, pp. 1043–1050.

[8] Z. Babić, M. Šljivić, "Application of tailored blanks in the automotive industry", J. Technol. Plast., Vol. 27, 2002, pp. 61-71.

[9] S.K. Panda, V.H.B. Hernandez, M.L. Kuntz, Y. Zhou, "Formability analysis of diode-laser-welded tailored blanks of advanced high-strength steel sheets", Metal. Mater. Trans. A, Vol. 40, 2009, pp. 1955-1967.

[10] Q. Jia, W. Guo, W. Li, Y. Zhu, P. Peng, G. Zou, "Microstructure and tensile behavior of fiber laser-welded blanks of DP600 and DP980 steels", J. Mater. Proc. Technol., Vol. 236, 2016, pp. 73-83.

[11] S. Li, Y. Kang, G. Zhu, S. Kuang, "Microstructure and fatigue crack growth behavior in tungsten inert gas welded DP780 dual-phase steel", Mater. Des., Vol. 85, 2015, pp. 180-189.

[12] A. Ramazani, K. Mukherjee, A. Abdurakhmanov, U.Prahl, M.Schleser, U.Reisgen, W.Bleck, "Micro–macro-characterisation and modelling of mechanical properties of gas metal arc welded (GMAW) DP600 steel", Mater. Sci. Eng. A, Vol. 589, 2014, pp. 1-14.

[13] A.A. Kuril, M. Jagannatham, G.D.J. Ram, S.R. Bakshi, "Transmission electron microscopy studies of plasma arc-welded DP600 dual-phase steel in keyhole mode", Metal. Mater. Trans. A, Vol. 50, 2019, pp. 5689–5699

[14] Q. Jia, W. Guo, W. Li, P. Peng, Y. Zhu, G. Zou, Y. Peng, Z. Tian, "Experimental and numerical study on local mechanical properties and failure analysis of laser welded DP980 steels", Mater. Sci. Eng. A, Vol. 680, 2017, pp. 378-387.

[15] H. Ashrafi, M. Shamanian, R. Emadi, M.A. Sarmadi, "Effect of welding parameters on the microstructure and tensile properties of friction stir-welded DP600 steel", SAE Int. J. Mater. Manuf., Vol. 12, 2019, pp. 165-178.

[16] H. Ashrafi, M. Shamanian, R. Emadi, M.A. Sarmadi, "Comparison of microstructure and tensile properties of dual phase steel welded using friction stir welding and gas tungsten arc welding", Steel Res. Intl., Vol. 89, 2018, pp. 1700427.

[17] M.D. Sameer, A.K. Birru, "Investigations on microstructural evolutions and mechanical properties of dual-phase 600 steel and AA6082-T6 aluminum alloy dissimilar joints fabricated by friction stir welding", Trans Indian Inst Met Vol. 72, 2019, pp. 353–367.

[18] S.K. Panda, M.L. Kuntz, Y. Zhou, "Finite element analysis of effects of soft zones on formability of laser welded advanced high strength steels", Sci. Technol. Weld. Join., Vol. 14, 2009, pp. 52-61.

[19] K. Bandyopadhyay, S.K. Panda, P. Saha, "Investigations into the influence of weld zone on formability of fiber laser-welded advanced high strength steel", J. Mater. Eng. Perform., Vol. 23,  2014, pp. 1465–1479.

[20] E. Biro, J.R. Mcdermid, J.D. Embury, Y. Zhou, "Softening kinetics in the subcritical heat-affected zone of dual-phase steel welds", Metal. Mater. Trans. A, Vol. 41, 2010, pp. 2348-2356.

[21] M. Xia, E. Biro, Z. Tian, Y.N. Zhou, "Effects of heat input and martensite on haz softening in laser welding of dual phase steels", ISIJ Int., Vol. 48, 2008, pp. 809–814.

[22] P.C. Huan, X.N. Wang, L. Yang, Z. Zheng, Z.R. Hu, M. Zhang, C.J. Chen, "Effect of martensite content on failure behavior of laser welded dual-phase steel joints during deformation", J. Mater. Eng. Perform., Vol. 28, pp. 1801-1809.

[23] C. Wei, J. Zhang, S. Yang, L. Sun, W. Tao, F. Wu, W. Xia, "Improving formability of laser welded automotive dual phase steels with local cooling", Sci. Technol. Weld. Join., Vol. 20, 2015, pp. 145-154.

[24] H. Ashrafi, M. Shamanian, R. Emadi, N. Saeidi, "Microstructure, tensile properties and work hardening  behavior of GTA-welded dual-phase steels", J. Mater. Eng. Perform., Vol. 26, 2017, pp. 1414-1423.

[25] ASTM E3, "Standard practice for preparation of metallographic specimens", ASTM, 2017.

[26] ASTM E112, "Standard test methods for determining average grain size", ASTM, 2004.

[27] ASTM E562, "Determining volume fraction by systematic manual point count", ASTM, 2004.

[28] ASTM E384, "Standard test method for microindentation hardness of materials", ASTM, 2016.

[29] V.H.B. Hernandez, S.K. Panda, Y. Okita, N.Y. Zhou, "A study on heat affected zone softening in resistance spot welded dual phase steel by nanoindentation", J Mater Sci, Vol. 45, 2010, pp. 1638–1647.

[30] R. Ghomashchi, W. Costin, R. Kurji, "Evolution of weld metal microstructure in shielded metal arc welding of X70 hsla steel with cellulosic electrodes: A case study", Mater. Charact., Vol. 107,  2015, pp. 317-326.

[31] H. Seyedrezai, A.K. Pilkey, J.D. Boyd, "Effect of pre-ic annealing treatments on the final microstructure and workhardening behavior of a dual-phase steel", Mater. Sci. Eng. A, Vol. 594,  2014, pp. 178-188.

[32] M. Kulakov, W.J. Poole, M. Militzer, "The effect of the initial microstructure on recrystallization and austenite formation in a DP600 steel", Metal. Mater. Trans. A, Vol. 44, 2013, pp. 3564–3576.

[33] P. Li, J. Li, Q. Meng, W. Hu, D. Xu, "Effect of heating rate on ferrite recrystallization and austenite formation of cold-roll dual phase steel", J. Alloy Cmpd., Vol. 578, 2013, pp. 320-327.

[34] H. Ashrafi, M. Shamanian, R. Emadi, N. Saeidi, "Correlation of tensile properties and strain hardening behavior with martensite volume fraction in dual-phase steels", Trans. Indian Inst. Met., Vol. 70, 2017, pp. 1575–1584.

[35] D. Das, P.P. Chattopadhyay, "Influence of martensite morphology on the work-hardening behavior of high strength ferrite–martensite dual-phase steel", J. Mater. Sci., Vol. 44, 2009, pp. 2957–2965.

[36] E. Ahmad, T. Manzoor, M.M.A. Ziai, N. Hussain, "Effect of martensite morphology on tensile dof dual-phase steel", J. Mater. Eng. Perform., Vol. 21, 2012, pp. 382-387.

[37] H. Ashrafi, S. Sadeghzade, R. Emadi, M. Shamanian, "Influence of heat treatment schedule on the tensile properties and wear behavior of dual phase steels", Steel Res. Intl., Vol. 88, 2017, pp. 1600213.

[38] U.F. Kocks, H. Mecking, "Physics and phenomenology of strain hardening: The fcc case", Prog. Mater. Sci., Vol. 48, 2003, pp. 171–273.

[39] G. Sainath, B.K. Choudhary, J. Christopher, E.I. Samuel, M.D. Mathew, "Applicability of voce equation for tensile flow and work hardening behaviour of P92 ferritic steel", Int. J. Press. Ves. Pip., Vol. 132–133, 2015, pp. 1-9.

[40] N. Saeidi, F. Ashrafizadeh, B. Niroumand, "Development of a new ultrafine grained dual phase steel and examination of the effect of grain size on tensile deformation behavior", Mater. Sci. Eng. A, Vol. 599, 2014, pp. 145-149.

[41] M. Mazinani, W.J. Poole, "Effect of martensite plasticity on the deformation behavior of a low-carbon dual-phase steel", Metal. Mater. Trans. A, Vol. 38, 2007, pp. 328–339.

[42] J.H. Hollomon, "Tensile deformation", Am. Inst. Min. Metall. Eng. Trans. Iron Steel Div., Vol. 162, 1945, pp. 268–289.

[43] P. Movahed, S. Kolahgar, S.P.H. Marashi, M. Pouranvari, N. Parvin, "The effect of intercritical heat treatment temperature on the tensile properties and work hardening behavior of ferrite-martensite dual phase steel sheets", Mater. Sci. Eng. A, Vol. 518, 2009, pp. 1-6.