Abstract
The microstructure and the mechanical properties of a low-carbon Al/Si-alloyed carbide-free bainitic steel austempered at temperatures between 300 and 350 °C have been investigated by means of optical microscopy, scanning electron microscopy, transmission electron microscopy, x-ray diffraction analysis, and mechanical property tests. The results show that an excellent combination of tensile strength, ductility, and impact toughness is obtained at the austempering temperature of 320 °C—but neither at the lowest temperature of 300 °C nor at the highest temperature of 350 °C. These results are correlated with the features of the constituent phases of the microstructure, especially the amount and size of retained austenite, which are largely dependent on the austempering temperature. The observations are also due to the inconsistent effects of strain-induced martensitic transformation on strength, ductility, and toughness. The results of the present study suggest that an optimized isothermal temperature may also exist for any other bainitic steel, at which, if austempering treatment is carried out, an improved combination of tensile and impact properties can be obtained.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
M. De Meyer, D. Vanderschueren, and B.C. DeCooman, The Influence of the Substitution of Si by Al on the Properties of Cold Rolled C-Mn-Si TRIP Steels, ISIJ Int., 1999, 39, p 813–822
F.G. Caballero, H.K.D.H. Bhadeshia, K.J.A. Mawella, D.G. Jones, and P. Brown, Very Strong Low Temperature Bainite, Mater. Sci. Technol., 2002, 18, p 279–284
M. Soliman and H. Palkowski, Ultra-Fine Bainite Structure in Hypo-Eutectoid Steels, ISIJ Int., 2007, 47, p 1703–1710
C. Carcia-Mateo and F.G. Caballero, The Role of Retained Austenite on Tensile Properties of Steels with Bainitic Microstructures, Mater. Trans., 2005, 46, p 1839–1846
F.G. Caballero, M.J. Santofimia, C. García-Mateo, J. Chao, and C. García de Andrés, Theoretical Design and Advanced Microstructure in Super High Strength Steels, Mater. Des., 2009, 30, p 2077–2083
H.S. Yang and H.K.D.H. Bhadeshia, Designing Low Carbon, Low Temperature Bainite, Mater. Sci. Technol., 2008, 24, p 335–341
T. Hojo, K. Sugimoto, Y. Mukai, and S. Ikeda, Effects of Aluminum on Delayed Fracture Properties of Ultra High Strength Low Alloy TRIP-Aided Steels, ISIJ Int., 2008, 48, p 824–829
A. Barbacki and E. Mikolajski, Optimization of Heat Treatment Conditions for Maximum Toughness of High Strength Silicon Steel, J. Mater. Process. Technol., 1998, 78, p 18–23
G. Lacroix, T. Pardoen, and P.J. Jacques, The Fracture Toughness of TRIP-Assisted Multiphase Steels, Acta Mater., 2008, 56, p 3900–3913
H.K.D.H. Bhadeshia, High Performance Bainitic Steels, Mater. Sci. Forum, 2005, 500(501), p 63–74
Q. Zhou, L. Qian, J. Tan, J. Meng, and F. Zhang, Inconsistent Effects of Mechanical Stability of Retained Austenite on Ductility and Toughness of Transformation-Induced Plasticity Steels, Mater. Sci. Eng. A, 2013, 578, p 370–376
D.J. Dyson and B. Holmes, Effect of Alloying Additions on the Lattice Parameter of Austenite, J. Iron Steel Inst., 1970, 208, p 469–474
C. Garcia-Mateo, F.G. Caballero, and H.K.D.H. Bhadeshia, Acceleration of Low-Temperature Bainite, ISIJ Int., 2003, 43, p 1821–1825
G.E. Dieter, Mechanical Metallurgy, McGraw-Hill, New York, 1986
L. Qian, Q. Zhou, F. Zhang, J. Meng, M. Zhang, and Y. Tian, Microstructure and Mechanical Properties of a Low Carbon Carbide-Free Bainitic Steel Co-Alloyed with Al and Si, Mater. Des., 2012, 39, p 264–268
H.K.D.H. Bhadeshia, Bainite in Steels, IOM Commercial Ltd, London, 2001
C. García-Mateo and F.G. Caballero, Ultra-High-Strength Bainitic Steels, ISIJ Int., 2005, 45, p 1736–1740
J.M. Rigsbee and P.J. Vander Arend, Formable HSLA and Dual-Phase Steel, A.T. Davenport, Ed., TMS-AIME, Warrendale, 1979, p 56-86
I.B. Timokhina, P.D. Hodgson, and E.V. Pereloma, Effect of Deformation Schedule on the Microstructure and Mechanical Properties of a Thermomechanically Processed C-Mn-Si Transformation-Induced Plasticity Steel, Metall. Mater. Trans. A, 2003, 34A, p 1599–1609
K.I. Sugimoto, Fracture Strength and Toughness of Ultra High Strength TRIP Aided Steels, Mater. Sci. Technol., 2009, 25, p 1108–1117
S.D. Antolovich and B. Singh, On the Toughness Increment Associated with the Austenite to Martensite Phase Transformation in TRIP Steels, Metall. Trans., 1971, 2, p 2135–2141
S.D. Antolovich and A. Saxena, A Model for Fatigue Crack Propagation, Eng. Fract. Mech., 1975, 7, p 649–652
D.A. Curry and J.F. Knott, Effect of Microstructure on Cleavage Fracture Toughness of Quenched and Tempered Steels, Met. Sci., 1979, 13, p 341–345
L. Qian, H. Toda, S. Nishido, and T. Kobayashi, Experimental and Numerical Investigations of the Effects of the Spatial Distribution of α Phase on Fracture Behavior in Hypoeutectic Al-Si Alloys, Acta Mater., 2006, 54, p 4881–4893
H.K.D.H. Bhadeshia, Martensite and Bainite in Steels: Transformation Mechanism and Mechanical Properties, J. Phys. IV France, 1997, 7(C5), p 367–376
Acknowledgments
This work was supported by the Natural Science Foundation of HeBei Province (Grant No. E2015203106) and Hebei Province High School Science Research Project (Grant No. ZD2014044).
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Meng, J., Feng, Y., Zhou, Q. et al. Effects of Austempering Temperature on Strength, Ductility and Toughness of Low-C High-Al/Si Carbide-Free Bainitic Steel. J. of Materi Eng and Perform 24, 3068–3076 (2015). https://doi.org/10.1007/s11665-015-1567-1
Received:
Revised:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11665-015-1567-1