An Investigation on the Development of Hard and Strong Bainitic Steels by very Short Heat Treatments

Abstract:

An attempt has been made in this research work to develop strong and tough bainitic steels in shorter transformation durations of less than three hours leading to ease of production for steel industries making these steels. High carbon medium alloy steel with high amounts of silicon, cobalt and aluminum was taken up for this study. The steel samples were austempered at 473, 523, 573, and 623K for 30, 45, 60, 90, 120, 150, and 180 minutes and then characterized by optical metallography, scanning electron microscopy, transmission electron microscopy and X-ray diffraction investigations. Microstructure containing plates of bainitic ferrite and substantial amounts of retained austenite placed in between the bainitic ferrite laths was produced. The steel after austempering had hardness in the range 450 – 720 HV at 30 kg load, tensile strength of about 560-620 MPa and room temperature notch impact toughness of about 10J with very less ductility. The details of alloy design and making, metallurgical and mechanical characterizations are discussed.

• Periodical: Applied Mechanics and Materials (Volumes 592-594)
• Pages: 1240-1244
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.592-594.1240
• Online since: July 2014
• Authors: K. Thillairajan*, V. Balusamy, V. Ramaswamy
• Keywords: Austempering, Bainitic Ferrite, Retained Austenite, Short Transformation

References

[1] H.K.D.H. Bhadeshia: Bainite in Steels – Transformations, Microstructure and Properties (IOM communications limited, London 2001).

[2] F.G. Caballero, H.K.D.H. Bhadeshia, K.J. A Mawella, D.G. Jones and P. Brown: Mater Sci Tech, Vol. 17, (2001), pp.512-516.

[3] F.G. Caballero, H.K.D.H. Bhadeshia, K.J.A. Mawella, D.G. Jones and P. Brown: Mater Sci Tech, Vol. 17, (2001), pp.517-522.

[4] H.S. Yang and H.K.D.H. Bhadeshia: Mater Sci Tech, Vol. 24 (2008), p.335– 341.

[5] Fang Hong-sheng, Feng Chun, Zheng Yan-kang, Yang Zhi-gang and Bai Bing-zhe: Iron Steel Res Int, Vol. 15(6) (2008), pp.1-9.

[6] H.K.D.H. Bhadeshia: Met Sci, Vol. 16, (1982), pp.159-165.

[7] H.K.D.H. Bhadeshia: Scripta Mater, Vol. 59 (2008), p.1275–1276.

[8] H.K.D. H Bhadeshia and F. G Caballero: ISSI International, Vol. 1 (2004) No 1, pp.15-23.

[9] C. Garcia–Mateo, F.G. Caballero and H.K.D.H. Bhadeshia: J de Physique IV, Vol. 112 (2003) p.285–288.

DOI: 10.1051/jp4:2003884

[10] C. Garcia–Mateo, F.G. Caballero and H.K.D.H. Bhadeshia: ISIJ International, Vol. 43 (2003), No. 11, p.1821–1825.

DOI: 10.2355/isijinternational.43.1821

[11] F.G. Caballero and H.K.D.H. Bhadeshia: Curr Opin Solid St M, Vol. 8 (2004), pp.251-257.

[12] Manabu Takahashi: J Curr Opin Solid St M, Vol. 8 (2004), p.213–217.

[13] J. Wang, P.J. Van der wolk and S. Van der zwaag: J Mater Sci, Vol. 35 (2000), p.4393 – 4404.

DOI: 10.1023/a:1004865209116

[14] C. Fossaet, G. Rees, T. Maurickx and H.K.D.H. Bhadeshia: Metall Mater Trans A, Vol. 26A (1995), pp.21-30.

[15] Zhi-Gang Yang and Hong-Sheng Fang: Curr Opin Solid St M, Vol. 9 (2005), pp.277-286.

[16] F.G. Caballero, J. Chao, J. Cornide, C. García-Mateo, M.J. Santofimia and C. Capdevila: Mat Sci Eng A Struct, Vol. 525 (2009), pp.87-95.

DOI: 10.1016/j.msea.2009.06.034

[17] C. Garcia–Mateo and F.G. Caballero, ISIJ International, Vol. 45 (2005), No. 11, p.1736–1740.

[18] H.K.D.H. Bhadeshia and D.V. Edmonds: Metal Science, Vol. 17, (1983), pp.411-419.

[19] H.K.D.H. Bhadeshia and A.R. Waugh: Acta Metallurgica, Vol. 30 (1982), p.775–784.

[20] F.G. Caballero, H.K.D.H. Bhadeshia K.J.A. Mawella and D.G. Jones: Mater Sci Tech, Vol. (2002), pp.279-284.

[21] S.A. Sajjadi and S.M. Zebarjad: Mater Process Technol, Vol. 189 (2007), pp.107-113.