Microstructure and Tensile Properties of TRIP-Aided Steel Sheet Subjected to Hot-Rolling and Austempering

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Abstract:

Various high strength steel sheets for weight reduction and safety improvement of vehicles have been developed. TRIP-aided steel with transformation induced plasticity of the retained austenite has high strength and ductility. Conventional TRIP-aided steels are subjected to austempering process after austenitizing. Generally, elongation and formability of TRIP-aided steel are improved by finely dispersed retained austenite in BCC phase matrix. The finely dispersed retained austenite and grain refinement of TRIP-aided steel can be achieved by hot rolling with heat treatment. Therefore, the improvement of mechanical properties of TRIP-aided steel is expected from the manufacturing process with hot rolling and then isothermal transformation process. In this study, thermomechanical heat treatment is performed by combining hot rolling and isothermal holding as the manufacturing process of TRIP-aided steel sheets. The complex phase matrix is obtained by hot rolling and then isothermal holding. Although the hardness of the hot rolled and isothermal held TRIP-aided steel is decreased, the volume fraction of retained austenite is increased.

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Materials Science Forum (Volume 1016)

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732-737

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January 2021

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© 2021 Trans Tech Publications Ltd. All Rights Reserved

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[1] R. Rana, S.B. Singh, Automotive Steels, Woodhead Publishing, Cambridge, (2016).

Google Scholar

[2] K. Sugimoto, T. Hojo, J. Kobayashi, Critical assessment 29: TRIP-aided bainitic ferrite steels, Mat. Sci. and Technol. 33 (2017) 2005-2009.

DOI: 10.1080/02670836.2017.1356014

Google Scholar

[3] J.G. Speer, D.V. Edmonds, F.C. Rizzo, D.K. Matlock, Partitioning of carbon from supersaturated plates of ferrite with application to steel processing and fundamentals of the bainitic transformation, Curr. Opin. Solid State Mat. Sci. 8 (2004) 219-237.

DOI: 10.1016/j.cossms.2004.09.003

Google Scholar

[4] H.K.D.H. Bhadeshia, Some phase transformations in steels, Mater. Sci. Technol. 15 (1999) 22-29.

Google Scholar

[5] W. Cao, C. Wang, J. Shi, M. Wang, W. Hui, H. Dong, Microstructure and mechanical properties of Fe-0.2C-5Mn steel processed by ART-annealing, Mater. Sci. Eng. A 528 (2011) 6661-6666.

DOI: 10.1016/j.msea.2011.05.039

Google Scholar

[6] K. Sugimoto, H. Tanino, J. Kobayashi, Impact toughness of medium-Mn transformation-induced plasticity-aided steels, Steel Res. Int. 86 (2015) 1151-1160.

DOI: 10.1002/srin.201400585

Google Scholar

[7] K. Sugimoto, J. Sakaguchi, T. Iida, T. Kashima, Stretch-flangeability of a High-strength TRIP Type Bainitic Sheet Steel, ISIJ Int. 40 (2000) 920-926.

DOI: 10.2355/isijinternational.40.920

Google Scholar

[8] J. Kobayashi, D. Ina, Y. Nakajima, K. Sugimoto, Effects of microalloying on the impact toughness of ultrahigh-strength TRIP-aided martensitic steels, Metall. Mater. Trans. A 44A (2013) 5006–5017.

DOI: 10.1007/s11661-013-1882-9

Google Scholar

[9] K. Sugimoto, S. Sato, G. Arai, Hot Forging of Ultra High-Strength TRIP-Aided Steel, Mat. Sci. Frorum 638-642 (2010) 3074-3079.

DOI: 10.4028/www.scientific.net/msf.638-642.3074

Google Scholar

[10] J. Kobayashi, K. Sugimoto, G. Arai, Effects of Hot-Forging Process on Combination of Strength and Toughness in Ultra High-Strength TRIP-Aided Martensitic Steels, Adv. Mat. Res. 409 (2012) 696-701.

DOI: 10.4028/www.scientific.net/amr.409.696

Google Scholar