Revealing the Microstructure and Mechanical Properties of Rapidly Quenched and Tempered 51CrV4 Steel Processed Via a Continuous Induction Line

Abstract:

This study investigates the microstructural evolution and mechanical response of 51CrV4 spring steel subjected to flash quenching and tempering using a continuous high-speed induction heating line. The steel, supplied as 8 mm thick sheets with a composition of Fe–0.5C–0.9Mn–1Cr–0.16V (wt.%), was processed through rapid austenitisation at 900 °C (~200 °C/s), followed by water quenching and tempering at 300 °C. Rapid induction heat treatment was utilized to produce a hardened surface layer with refined microstructure and balanced mechanical properties. Optical microscopy revealed a uniform, crack-free martensitic layer extending to approximately ~1.2 mm from the surface, while hardness profiling showed a gradient from 590 ± 20 HV at the surface to 240–330 HV in the core. Electron Backscatter Diffraction (EBSD) analysis confirmed a fully martensitic surface structure with refined prior austenite grains (~3.2 µm), and FESEM imaging indicated minimal carbide coarsening, supporting the effectiveness of short-time tempering. These results demonstrate that flash induction processing can produce a hardened shell with retained core ductility. The consistency between EBSD, FESEM, and hardness data validates the process as an energy-efficient, scalable alternative to conventional furnace-based treatments.

• Periodical: Solid State Phenomena (Volume 383)
• Pages: 7-12
• DOI: https://doi.org/10.4028/p-69oURO
• Online since: January 2026
• Authors: Ahmed W. Abdelghany*, Oskari Haiko, Antti Järvenpää, Antti Kaijalainen
• Keywords: Flash Tempering, Induction Heating, Martensite, Mechanical Properties, Ultrahigh Strength Steel

References

[1] W. Hagedorn, A. Gramlich, K. Greiff, U. Krupp, Alloy and process design of forging steels for better environmental performance, Sustainable Materials and Technologies 34 (2022) e00509.

DOI: 10.1016/J.SUSMAT.2022.E00509

[2] D.K. Matlock, S. Kang, E. De Moor, J.G. Speer, Applications of rapid thermal processing to advanced high strength sheet steel developments, Mater Charact 166 (2020) 110397.

DOI: 10.1016/J.MATCHAR.2020.110397

[3] A. Järvenpää, S. Ghosh, A. Khosravifard, M. Jaskari, A. Hamada, A new processing route to develop nano-grained structure of a TRIP-aided austenitic stainless-steel using double reversion fast-heating annealing, Materials Science and Engineering: A 808 (2021) 140917.

DOI: 10.1016/J.MSEA.2021.140917

[4] N.S. Kim, G.G. Kang, An investigation of flow characteristics considering the effect of viscosity variation in the thixoforming process, J Mater Process Technol 103 (2000) 237–246.

DOI: 10.1016/S0924-0136(99)00441-0

[5] H.K. Jung, The induction heating process of semi-solid aluminium alloys for thixoforming and their microstructure evaluation, J Mater Process Technol 105 (2000) 176–190.

DOI: 10.1016/S0924-0136(00)00567-7

[6] A. Kaijalainen, O. Haiko, S. Sadeghpour, V. Javaheri, J. Kömi, The Influence of Rapid Tempering on the Mechanical and Microstructural Characteristics of 51CrV4 Steel, Metals 2024, Vol. 14, Page 60 14 (2024) 60.

DOI: 10.3390/MET14010060

[7] C. Lai, W. Huang, S. Li, T. Liu, R. Lv, X. Tang, J. Yu, Effects of quenching and tempering heat treatment on microstructure, mechanical properties, and fatigue crack growth behavior of 51CrV4 spring steel, Mater Res Express 8 (2021) 096514.

DOI: 10.1088/2053-1591/AC22C6

[8] J. Han, A.K. da Silva, D. Ponge, D. Raabe, S.M. Lee, Y.K. Lee, S.I. Lee, B. Hwang, The effects of prior austenite grain boundaries and microstructural morphology on the impact toughness of intercritically annealed medium Mn steel, Acta Mater 122 (2017) 199–206.

DOI: 10.1016/J.ACTAMAT.2016.09.048

[9] L. Zhang, D. Gong, Y. Li, X. Wang, X. Ren, E. Wang, Effect of Quenching Conditions on the Microstructure and Mechanical Properties of 51CrV4 Spring Steel, Metals 2018, Vol. 8, Page 1056 8 (2018) 1056.

DOI: 10.3390/MET8121056

[10] T. Furuhara, K. Kobayashi, T. Maki, Control of Cementite Precipitation in Lath Martensite by Rapid Heating and Tempering, ISIJ International 44 (2004) 1937–1944.

DOI: 10.2355/ISIJINTERNATIONAL.44.1937

[11] C. Revilla, B. López, J.M. Rodriguez-Ibabe, Carbide size refinement by controlling the heating rate during induction tempering in a low alloy steel, Materials & Design (1980-2015) 62 (2014) 296–304.

DOI: 10.1016/J.MATDES.2014.05.053

[12] P. Yadegari, H. Thomas Beier, M. Vormwald, A two-point fatigue strength assessment for surface-hardened notched components under consideration of residual stresses based on the local strain approach, Int J Fatigue 184 (2024) 108326.

DOI: 10.1016/J.IJFATIGUE.2024.108326