MECHANICAL AND METALLURGICAL PROPERTIES OF FRICTION-STIR-WELDED AISI 304 STAINLESS STEEL

Sundar raju Govindaraj; Sivakumar Karuppa

doi:10.17222/mit.2022.678

Sundar raju Govindaraj Department of Mechanical Engineering, Bannari Amman Institute of Technology, Erode, Tamil Nadu, India
Sivakumar Karuppa Department of Mechanical Engineering, Bannari Amman Institute of Technology, Erode, Tamil Nadu, India

DOI: https://doi.org/10.17222/mit.2022.678

Keywords: tensile strength, tool rotational speed, welding speed, axial load

Abstract

Friction stir welding of AISI 304 stainless-steel sheets was successfully carried out with a tungsten-alloy (W+La₂O₃) tool and the effect of the tool rotational speed on the microstructure and mechanical properties of the joints were evaluated. 3-mm-thick plates were friction-stir welded at various rotational speeds of 600–1000 min^–1 and a constant welding speed of 40 mm/min with a constant axial load of 15 kN. Defect-free joints were produced at 800 min^–1 and 900 min^–1, indicating a proper plastic flow of the material and ensuring adequate heat generation during welding. Tensile, Charpy impact, compression and microhardness tests were performed to evaluate the joint mechanical properties. The microstructural behavior of the welded and base-metal samples was examined with optical microscopy and scanning electron microscopy. According to the mechanical results, the welded material has a higher yield strength than the base metal due to the grain refinement and work hardening effect in the stir zone. FSW welds have a higher hardness than the base metal due to the high density of dislocations and continuous dynamic recrystallization. The joints also exhibit acceptable impact toughness. Finally, the EDS analysis confirms that there is no secondary-phase formation in the weld zone of the fabricated material.

References

1. Thomas, W. M. (1991). Friction stir butt welding. Int. Patent No. PCT/GB92/02203.
2. Dawes, C. J. (1995). Friction Stir Process Welds Aluminium Alloys. Welding Journal, 36.
3. Benavides, S., Li, Y., Murr, L., Brown, D., & McClure, J. (1999). Low-temperature friction-stir welding of 2024 aluminum. Scripta materialia, 41(8).
4. Australian Stainless magazine - Issue 6, October 1996. (https://www.assda.asn.au/43-applications/ marine/170-corrosion-resistance-in-marine-environments).
5. Gerwick Jr, B. C. (2007). Construction of marine and offshore structures. CRC press.
6. Mohan, D. G., & Wu, C. (2021). A Review on Friction Stir Welding of Steels. Chinese Journal of Mechanical Engineering, 34(1), 1-29.
7. Zhang, Y. N., Cao, X., Larose, S., & Wanjara, P. (2012). Reviews of tools for friction stir welding and processing. Canadian Metallurgical Quarterly, 51(3), 250-261.
8. Miyazawa, T., Iwamoto, Y., Maruko, T., & Fujii, H. (2012). Friction stir welding of 304 stainless steel using Ir based alloy tool. Science and Technology of Welding and Joining, 17(3), 207-212.
9. Lakshminarayanan, A. K., Ramachandran, C. S., & Balasubramanian, V. (2014). Feasibility of surface-coated friction stir welding tools to join AISI 304 grade austenitic stainless steel. Defense Technology, 10(4), 360-370.
10. Nathan, S. R., Balasubramanian, V., Malarvizhi, S., & Rao, A. G. (2016). An investigation on metallurgical characteristics of tungsten based tool materials used in friction stir welding of naval grade high strength low alloy steels. International Journal of Refractory Metals and Hard Materials, 56, 18-26.
11. Gharacheh, M. A., Kokabi, A. H., Daneshi, G. H., Shalchi, B., & Sarrafi, R. (2006). The influence of the ratio of “rotational speed/traverse speed”(ω/v) on mechanical properties of AZ31 friction stir welds. International Journal of Machine Tools and Manufacture, 46(15), 1983-1987.
12. Ahmed, M. M. Z., Wynne, B. P., & Martin, J. P. (2013). Effect of friction stir welding speed on mechanical properties and microstructure of nickel based super alloy Inconel 718. Science and Technology of Welding and Joining, 18(8), 680-687.
13. Guo, G., & Shen, Y. (2019). Frictions stir welding of dissimilar stainless steels: evaluation of flow pattern, microstructure and mechanical properties. Materials Research Express, 6(5), 056510.
14. Plaine, A. H., & Alcântara, N. G. D. (2014). Prediction of FSW defect-free joints of AISI 304 austenitic stainless steel through axial force profile understanding. Materials Research, 17, 1324-1327.
15. Mishra, R. S., & Ma, Z. Y. (2005). Frictions stir welding and processing. Materials science and engineering: R: reports, 50(1-2), 1-78.
16. Li, J., Liu, X., Li, G., Han, P., & Liang, W. (2017). Characterization of the microstructure, mechanical properties, and corrosion resistance of a friction-stir-welded joint of hyper duplex stainless steel. Metals, 7(4), 138.
17. Li, H. B., Jiang, Z. H., Feng, H., Zhang, S. C., Li, L., Han, P. D., & Li, J. Z. (2015). Microstructure, mechanical and corrosion properties of friction stir welded high nitrogen nickel-free austenitic stainless steel. Materials & Design, 84, 291-299.
18. Sivakumar, K., & Nathan, S. R. (2020). Influence of tool rotational speed on the mechanical and microstructural properties of AISI 316 Austenitic stainless steel friction stir welded joints. Materials Research Express, 6(12), 1265d7.
19. Guo, R., Shen, Y., Huang, G., Zhang, W., & Guan, W. (2018). Microstructures and mechanical properties of thin 304 stainless steel sheets by friction stir welding. Journal of adhesion science and Technology, 32(12), 1313-1323.
20. Kumar, S. S., Murugan, N., & Ramachandran, K. K. (2019). Identifying the optimal FSW process parameters for maximizing the tensile strength of friction stir welded AISI 316L butt joints. Measurement, 137, 257-271.
21. Yan, J., Gao, M., & Zeng, X. (2010). Study on microstructure and mechanical properties of 304 SS joints by TIG, laser and laser-TIG hybrid welding. Optics and Lasers in Engineering, 48(4), 512-517.
22. Park, S. H. C., Sato, Y. S., Kokawa, H., Okamoto, K., Hirano, S., & Inagaki, M. (2005). Microstructural characterization of stir zone containing residual ferrite in friction stir welded 304 austenitic stainless steel. Science and Technology of Welding and Joining, 10(5), 550-556.