Mechanical properties of a microalloyed bainitic steel after hot forging and tempering

Abstract
Figure/Table
References
Related Citation (15)

Download: PDF (0 KB) HTML (1 KB)
Export: BibTeX | EndNote (RIS)

Abstract Mechanical properties of a newly developed microalloyed bainitic steel were investigated after the hot forging, air cooling and tempering process. The microstructure of the as-forged bainitic steel mainly consists of granular bainite and ~20 vol.% martensite. The fraction of retained austenite remains unchanged until tempering at 200��C, above which it decreases significantly. The increase of tempering temperature leads to decreases of both ultimate tensile strength and total elongation but decreases of both yield strength and reduction of area. The maximum and minimum values of impact toughness were observed after tempering at around 200 and 400��C, respectively. These effects are mainly attributed to the decomposition of martensite/austenite constituents and the tempering effects in martensite. The tempering of the forged bainitic steel at around 200��C results in an excellent combination of strength and toughness, which is comparable to that of the conventional quenched-and-tempered 40Cr steel. Therefore, low-tempering treatment coupled with post-forging residual stress relieving is a feasible method to further improve the mechanical properties of the bainitic forging steel.

Key words�� Bainitic forging steel Mechanical properties Tempering Microstructure Granular bainite

Received: 20 June 2017 Published: 01 December 2017

	Service

	E-mail this article
	Add to my bookshelf
	Add to citation manager
	E-mail Alert
	RSS
	Articles by authors
	XU Zhi-Bao
	HUI Wei-Jun
	YU Tie-Hua
	ZHANG Yong-Jian
	DIAO Xiao-Li
	DIAO Xiu-Meng

Cite this article:

XU Zhi-Bao,HUI Wei-Jun,YU Tie-Hua��. Mechanical properties of a microalloyed bainitic steel after hot forging and tempering[J]. Journal of Iron and Steel Research International, 2017, 24(11): 1085-1094.

URL:

http://gt.chinamet.cn/Jweb_gtyjxb_en/EN/ OR http://gt.chinamet.cn/Jweb_gtyjxb_en/EN/Y2017/V24/I11/1085

[1]	S. Engineer, B. Huchtemann, V. Sch��ler, A view of the development and application of microalloyed medium carbon steels, Steel Res. 58 (1987) 369-376.
[2]	D.J. Naylor, Review of international activity on microalloyed engineering steels, Ironmak. Steelmak. 16 (1989) 246-252.
[3]	S.L. Chen, W.J. Hui, L.H. Wang, G.W. Dai, H. Dong, Research and development of energy-saving high performance microalloyed forging steels. Iron Steel 49(6) (2014) 1-7.
[4]	M.J. Balart, C.L. Davis, M. Strangwood, Fracture behaviour in medium-carbon Ti-V-N and V-N microalloyed ferritic-pearlitic and bainitic forging steels with enhanced machinability, Mater. Sci. Eng. A 328 (2002) 48-57.
[5]	D.K. Matlock, G. Krauss, J.G. Speer, Microstructures and properties of direct-cooled microalloy forging steels, J. Mater. Process. Technol. 117 (2001) 324-328.
[6]	F. Ishikawa, T. Takahashi, The formation of intragranular ferrite plates in medium-carbon steels for hot-forging and its effect on the toughness, ISIJ Inter. 35 (1995) 1128-1133.
[7]	A.R. Khodabandeh, M. Jahazi, S. Yue, P. Boocher, Impact toughness and tensile properties improvement through microstructure control in hot-forged Nb-V microalloyed steel, ISIJ Int. 45 (2005) 272-280.
[8]	L. Ceschini, A. Marconi, C. Martini, A. Morri, A. Di Schino, Tensile and impact behaviour of a microalloyed medium carbon steel: effect of the cooling condition and corresponding microstructure, Mater. Des. 45 (2013) 171-178.
[9]	W.J Hui, N. Xiao, X.L. Zhao, Y.J. Zhang, Y.F. Wu, Effect of vanadium on dynamic continuous cooling transformation behavior of medium-carbon forging steels, J. Iron Steel Res. Int. 24 (2017) 641-648.
[10]	B. Buchmayr, Critical assessment 22: bainitic forging steels, Mater. Sci. Technol. 32 (2016) 517-522.
[11]	T. Sourmail, V. Smanio, Optimisation of the mechanical properties of air cooled bainitic steel components through tailoring of the transformation kinetics, Mater. Sci. Eng. A 582 (2013) 257-261.
[12]	C. Keul, V. Wirths, W. Bleck, New bainitic steels for forgings, Arch. Civ. Mech. Eng. 12 (2012) 119-125.
[13]	Y. Luo, J.M. Peng, H.B. Wang, X.C. Wu, Effect of tempering on microstructure and mechanical properties of a non-quenched bainitic steel, Mater. Sci. Eng. A 527 (2010) 3433-3437.
[14]	H. Wu, C. Liu, Z.B. Zhao, Y. Zhao, S.Z. Zhu, Y.X. Liu, S. Bhole, Design of air-cooled bainitic microalloyed steel for a heavy truck front axle beam. Mater. Des. 27 (2006) 651-656.
[15]	J.K. Zhang, L. Dong, Y. Xin, G.R. Guo, Application of low carbon Mn-B bainitic steel to automobile front axle, Mater. Mech. Eng. 27(7) (2003) 42-44.
[16]	H. Takada, Alloy designing of high strength bainitic steels for hot forging, Tetsu-to-Hagan�� 88 (2002) 534-538.
[17]	S. Sharma, S. Sangal, K. Mondal, Development of new high-strength carbide-free bainitic steels, Metall. Mater. Trans. A 42 (2011) 3921-3933.
[18]	H. Zhang, X.L. Cheng, B.Z. Bai, H.S. Fang, The tempering behavior of granular structure in a Mn-series low carbon steel, Mater. Sci. Eng. A 528 (2011) 920-924.
[19]	H.S. Hasan, M.J. Peet, M-N. Avettand-F��no?l, H.K.D.H. Bhadeshia, Effect of tempering upon the tensile properties of a nanostructured bainitic steel, Mater. Sci. Eng. A 615 (2014) 340-347.
[20]	Z.H. Jiang, P. Wang, D.Z. Li, Y.Y. Li, Effects of tempering temperature on the microstructure and mechanical properties of granular bainite on 2.25Cr-1Mo-0.25V steel, Acta Metall. Sin. 51 (2015) 925-934.
[21]	Y.L. Zhou, T. Jia, X.J. Zhang, Z.Y. Liu, R.D.K. Misra, Investigation on tempering of granular bainite in an offshore platform steel, Mater. Sci. Eng. A 626 (2015) 352-361.
[22]	K.K. Wang, Z.L. Tan, G.H. Gao, X.L. Gui, R.D.K. Misra, B.Z. Bai, Ultrahigh strength-toughness combination in bainitic rail steel: the determining role of austenite stability during tempering, Mater. Sci. Eng. A 662 (2016) 162-168.
[23]	F.G. Caballero, H. Roelofs, St. Hasler, C. Capdevila, J. Chao, J. Cornide, C. Garcia-Mateo, Influence of bainite morphology on impact toughness of continuously cooled cementite free bainitic steels, Mater. Sci. Technol. 28 (2012) 95-102.
[24]	E. Mazancov��, K. Mazanec, Physical metallurgy characteristics of the M/A constituent formation in granular bainite, J. Mater. Process. Technol. 64 (1997) 287-292.
[25]	H.F. Lan, L.X. Du, R.D.K. Misra, Effect of microstructural constituent on strength-toughness combination in a low carbon bainitic steel, Mater. Sci. Eng. A 611 (2014) 194-200.
[26]	Y. You, C.J. Shang, L. Chen, S. Subramanian, Investigation on the crystallography of the transformation products of reverted austenite in intercritically reheated coarse grained heat affected zone, Mater. Des. 43 (2013) 485-491.
[27]	M.W. Tong, P.K.C. Venkatsurya, W.H. Zhou, R.D.K. Misra, B. Guo, K.G. Zhang, W. Fan, Structure-mechanical property relationship in a high strength microalloyed steel with low yield ratio: the effect of tempering temperature, Mater. Sci. Eng. A 609 (2014) 209-216.
[28]	A. Saha Podder, H.K.D.H. Bhadeshia, Thermal stability of retained austenite in bainitic steels, Mater. Sci. Eng. A 527 (2010) 2121-2128.
[29]	L. Rancel, M. G��mez, S.F. Medina, Influence of microalloying elements (Nb,V,Ti) on yield strength in bainitic steels, Steel Res. Int. 79 (2008) 947-953.