Nugget formation, microstructural features and strength of resistance spot welded cold-rolled dual-phase steel lap joints for automotive applications

Chakkaravarthi Rajarajan; Paramasivam Sivaraj; Tushar Sonar; Selvaraj Raja; Nallusamy Mathiazhagan

doi:10.1515/mt-2021-2195

Article

Nugget formation, microstructural features and strength of resistance spot welded cold-rolled dual-phase steel lap joints for automotive applications

Chakkaravarthi Rajarajan , Paramasivam Sivaraj , Tushar Sonar , Selvaraj Raja and Nallusamy Mathiazhagan

Published/Copyright: August 5, 2022

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From the journal Materials Testing Volume 64 Issue 8

Abstract

The main objective of this research paper is to investigate the nugget formation, microstructure and strength performance of DP 800 steel joints developed using resistance spot welding (RSW) process for automotive application. The influence of RSW parameters on nugget formation was studied using one variable at a time approach. The RSW joint showing optimum nugget area was further characterized for microstructural features and strength performance. The microstructural features of nugget were studied using optical and scanning electron microscopy (SEM). The lap tensile shear fractured specimens were analyzed using SEM for optimized condition. The microstructural features were correlated to the tensile shear strength and hardness of RSW joints. Results showed that welding current significantly influences the nugget formation than electrode force and welding time. The DP 800 RSW joints made using a welding current of 5.5 kA, an electrode pressure of 4.0 MPa and a welding time of 2.0 s disclosed defect free weld nugget of 7.28 mm diameter. It showed a higher tensile shear strength of 20 kN and microhardness of 564 HV thereby satisfying the requirement of automotive applications.

Keywords: dual-phase steel; microstructure; resistancespot welding; tensile shear fracture load; weld nugget

Corresponding author: Chakkaravarthi Rajarajan, Department of Mechanical Engineering, Meenakshi Ramaswamy Engineering College, Thathanur, Tamil Nadu, 621804, India, E-mail: rajachozhan93@gmail.com

Acknowledgement

The authors express sincere gratitude to Director, Centre for Materials Joining and Research, CEMAJOR, Annamalai University, Annamalai Nagar, Tamil Nadu State, India for providing the resistance spot welding facility. The authors are also grateful to the Alagppa University, Karaikudi for providing the material testing facility.

Author contribution: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.
Research funding: None declared.
Conflict of interest statement: The authors declare no conflicts of interest regarding this article.

References

[1] P. Zhang, J. Xie, Y. X. Wang, and J. Q. Chen, “Effects of welding parameters on mechanical properties and microstructure of resistance spot welded DP600 joints,” Sci. Technol. Weld. Join., vol. 6, no. 7, pp. 567–574, 2011, https://doi.org/10.1179/136217110x12813393169732.Search in Google Scholar

[2] G. S. Cole and A. M. Sherman, “Lightweight materials for automotive applications,” Mater. Charact., vol. 35, pp. 3–9, 1995, https://doi.org/10.1016/1044-5803(95)00063-1.Search in Google Scholar

[3] D. Zhao, Y. Wang, L. Zhang, and P. Zhang, “Effects of electrode force on microstructure and mechanical behavior of the resistance spot welded DP600 joint,” Mater. Des., vol. 50, pp. 72–77, 2013, https://doi.org/10.1016/j.matdes.2013.02.016.Search in Google Scholar

[4] A. Erencan and E. Rukiye, “Shunting effects on the resistance spot welding parameters of DP600,” Mater. Test., vol. 62, no. 1, pp. 97–103, 2020, https://doi.org/10.3139/120.111455.Search in Google Scholar

[5] M. Elitas, “Effects of welding parameters on tensile properties and fracture modes of resistance spot welded DP1200 steel,” Mater. Test., vol. 63, no. 2, pp. 124–130, 2021, https://doi.org/10.1515/mt-2020-0019.Search in Google Scholar

[6] Y. Akinay and F. Hayat, “Investigation of resistance spot welds between DP450 steel and aluminum alloys,” Mater. Test., vol. 58, no. 5, pp. 408–412, 2016, https://doi.org/10.3139/120.110873.Search in Google Scholar

[7] T. Sonar, V. Balasubramanian, S. Malarvizhi, T. Venkateswaran, and D. Sivakumar, “Microstructural characteristics and tensile properties of gas tungsten constricted arc (GTCA) welded Inconel 718 superalloy sheets for aeroengine components,” Mater. Test., vol. 62, no. 11, pp. 1099–1108, 2020, https://doi.org/10.3139/120.111576.Search in Google Scholar

[8] A. H. Önal and N. Kaya, “Effect and optimization of resistance spot welding parameters on the strength of welded hot-stamped parts,” Mater. Test., vol. 56, no. 6, pp. 466–471, 2014, https://doi.org/10.3139/120.110585.Search in Google Scholar

[9] I. Sevim, “Newly revealed features of fracture toughness behavior of spot welded dual phase steel sheets for automotive bodies,” Mater. Test., vol. 57, nos. 11–12, pp. 960–967, 2015, https://doi.org/10.3139/120.110798.Search in Google Scholar

[10] E. Javaheri, A. Pittner, B. Graf, and M. Rethmeier, “Mechanical properties characterization of resistance spot welded DP1000 steel under uniaxial tensile tests,” Mater. Test., vol. 61, no. 6, pp. 527–532, 2019, https://doi.org/10.3139/120.111349.Search in Google Scholar

[11] N. Akkaş, E. İlhan, S. Aslanlar, and F. Varol, “The effect of nugget sizes on mechanical properties in resistance spot welding of SPA-C atmospheric corrosion resistant steel sheets used in rail vehicles,” Mater. Test., vol. 56, no. 10, pp. 879–883, 2014, https://doi.org/10.3139/120.110646.Search in Google Scholar

[12] C. Sawanishi, T. Ogura, K. Taniguchi, et al.., “Mechanical properties and microstructures of resistance spot welded DP980 steel joints using pulsed current pattern,” Sci. Technol. Weld. Join., vol. 19, no. 1, pp. 52–59, 2014, https://doi.org/10.1179/1362171813Y.0000000165.Search in Google Scholar

[13] H. Sun, X. Lai, Y. Zhang, and J. Shen, “Effect of variable electrode force on weld quality in resistance spot welding,” Sci. Technol.Weld. Join., vol. 12, no. 8, pp. 718–724, 2007, https://doi.org/10.1179/174329307x251862.Search in Google Scholar

[14] M. Pouranvari, S. P. H. Marashi, and S. M. Mousavizadeh, “Failure mode transition and mechanical properties of similar and dissimilar resistance spot welds of DP600 and low carbon steels,” Sci.Technol. Weld. Join. vol. 15, no. 7, pp. 625–631, 2010, https://doi.org/10.1179/136217110x12813393169534.Search in Google Scholar

[15] K. O. H. Marwan and R. Kaçar, “Optimization of welding parameters for DP600/TRIP800 dissimilar joints,” Mater. Test., vol. 60, no. 1, pp. 40–48, 2018, https://doi.org/10.3139/120.111116.Search in Google Scholar

[16] M. Elitas and B. Demir, “Residual stress evaluation during RSW of DP600 sheet steel,” Mater.Test., vol. 62, no. 9, pp. 888–890, 2020, https://doi.org/10.3139/120.111560.Search in Google Scholar

[17] K. Kishore, P. Kumar, and G. Mukhopadhyay, “Resistance spot weldability of galvannealed and bare DP600 steel,” J. Mater. Process. Technol., vol. 271, pp. 237–248, 2019, https://doi.org/10.1016/j.jmatprotec.2019.04.005.Search in Google Scholar

[18] F. Nikoosohbat, S. Kheirandish, M. Goodarzi, M. Pouranvari, and S. P. H. Marashi, “Microstructure and failure behaviour of resistance spot welded DP980 dual phase steel,” Mater. Sci. Technol., vol. 26, no. 6, pp. 738–744, 2010, https://doi.org/10.1179/174328409X414995.Search in Google Scholar

[19] T. Sonar, V. Balasubramanian, S. Malarvizhi, T. Venkateswaran, and D. Sivakumar, “Effect of heat input on evolution of microstructure and tensile properties of gas tungsten constricted arc (GTCA) welded inconel 718 alloy joints,” Metallogr. Microstruct. Anal., vol. 9, pp. 369–392, 2020, https://doi.org/10.1007/s13632-020-00654.Search in Google Scholar

[20] T. Sonar, S. Malarvizhi, and V. Balasubramanian, “Influence of arc constriction current (ACC) on microstructural evolution and tensile properties of tungsten inert gas welded thin sheets of aerospace alloy,” Aust. J. Mech. Eng., pp. 1–23, 2020, (In Press), https://doi.org/10.1016/10.1080/14484846.2020.1794512.Search in Google Scholar

[21] T. Sonar, S. Malarvizhi, and V. Balasubramanian, “Influence of arc constriction current frequency on tensile properties and microstructural evolution of tungsten inert gas welded thin sheets of aerospace alloy,” Trans. Nonferrous Metals Soc. China, vol. 31, no. 2, pp. 456–474, 2021, https://doi.org/10.1016/S1003-6326(21)65509-7.Search in Google Scholar

[22] T. Sonar, V. Balasubramanian, S. Malarvizhi, T. Venkateswaran, and D. Sivakumar, “Influence of magnetically constricted arc traverse speed (MCATS) on tensile properties and microstructural characteristics of welded Inconel 718 alloy sheets,” Defence Technol., vol. 17, no. 4, pp. 1395–1413, 2021, https://doi.org/10.1016/j.dt.2020.07.009.Search in Google Scholar

[23] H. Baltazar, S. K. Panda, Y. Okita, and N. Y. Zhou, “A study on heat affected zone softening in resistance spot welded dual phase steel by nanoindentation,” J. Mater. Sci., vol. 45, no. 6, pp. 1638–1647, 2010, https://doi.org/10.1007/s10853-009-4141-0.Search in Google Scholar

[24] W. Tong, H. Tao, and N. Zhang, “Deformation and fracture of miniature tensile bars with resistance-spot-weld microstructures,” Metall. Mater. Trans., vol. 36, no. 10, pp. 2651–2669, 2005, https://doi.org/10.1007/s11661-005-0263-4.Search in Google Scholar

[25] K. Bag, K. Ray, and E. S. Dwarakadasa, “Influence of martensite content and morphology on the toughness and fatigue behaviour of high-martensite dual-phase steels,” Metall. Mater. Trans., vol. 32, no. 9, pp. 2207–2217, 2001, https://doi.org/10.1007/s11661-001-0196-5.Search in Google Scholar

Published Online: 2022-08-05

Published in Print: 2022-08-26

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Articles in the same Issue

https://doi.org/10.1515/mt-2021-2195

Keywords for this article

dual-phase steel; microstructure; resistancespot welding; tensile shear fracture load; weld nugget