PSI - Issue 71

Ganesan G et al. / Procedia Structural Integrity 71 (2025) 438–444

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absorbing more energy during deformation. Fig. 7 shows that UTS increases from 470-485 MPa at 0% austenite to 652 675 MPa at 12.5-13.5%. Conventional ER70S-R has a 480 – 520 MPa UTS, and SS-304 ranges from 515 – 600 MPa. The fabricated heterogeneous steel alloy achieves a UTS of 663.5 MPa, a 186 MPa (~39%) increase, due to the combined effects of ferrite, austenite, and refined microstructure.

Fig.7. Effect of % of Austenite on ultimate tensile strength (a) and yield strength (b)

. 4. Conclusion

This study successfully utilized an in-house developed multi-wire GTAW-based WAAM system to fabricate heterogeneous steel alloys from Mild Steel ER70S-6 and SS-304. The results demonstrate a strong relationship between the austenite and ferrite phases, with higher SS-304 feed rates increasing austenite content and enhancing mechanical properties. The optimal phase fractions that resulted in the best combination of hardness and UTS were found at 12.5% to 13.5% austenite, yielding significant increases in microhardness and UTS. Microhardness reached 281 – 293 HV at this phase fraction, and UTS improved to 652 – 675 MPa. The combined effect of ferrite and austenite phases and compositional and microstructural refinement enabled the alloy to achieve enhanced performance compared to conventional alloys. References: Abe, T., Sasahara, H., 2016. Dissimilar metal deposition with a stainless steel and nickel-based alloy using wire and arc-based additive manufacturing. Precision Engineering, 45, 387 – 395. Bandyopadhyay, A., Heer, B., 2018. Additive manufacturing of multi-material structures. Materials Science and Engineering: R: Reports, 129, 1 – 16. Ahsan, M.R.U., Tanvir, A.N.M., Ross, T., Elsawy, A., Oh, M.S., Kim, D.B., 2020. Fabrication of bimetallic additively manufactured structure (BAMS) of low carbon steel and 316L austenitic stainless steel with wire+arc additive manufacturing. Rapid Prototyping Journal, 26(3), 519 – 530. Ayan, Y., Kahraman, N., 2022. Fabrication and characterization of functionally graded material (FGM) structure containing two dissimilar steels (ER70S-6 and 308LSi) by wire arc additive manufacturing (WAAM). Materials Today Communications, 33, 104457. Gupta, N.K., Ganesan, G., Siddhartha, S., Karade, S.R., Singh, S.D., Karunakaran, K.P., 2024. A dual-sided deposition technique to mitigate deformation in wire arc additive manufacturing. Transactions of the Indian Institute of Metals, 1 – 10. Gupta, N.K., Ganesan, G., Siddhartha, S., Karade, S.R., Paul, A.K., Dubey, S., Ely, R.H., Karunakaran, K.P., 2024. In situ pre-heating in wire arc additive manufacturing: Design, development, and experimental investigation on residual stresses and metallurgical and mechanical properties. Journal of Materials Engineering and Performance, 1 – 12. Kabaldin, Y., Shatagin, D., Ryabov, D., Solovyov, A., Kurkin, A., 2023. Microstructure, phase composition, and mechanical properties of a layered bimetallic composite ER70S-6 – ER309LSi obtained by the WAAM method. Metals, 13(5), 851. Karunakaran, K.P., Gupta, N.K., Patel, A.K., Rakeshkumar, K., Ganesan, G., Sealy, M., Bernard, A., 2022. Multi-station multi-axis hybrid layered manufacturing (MSMA-HLM). Manufacturing Letters, 33, 630 – 639.