Metals and Materials International

, Volume 24, Issue 4, pp 693–701 | Cite as

Microstructure and Mechanical Properties of Austempered Medium-Carbon Spring Steel

  • Seong Hoon Kim
  • Kwan-Ho Kim
  • Chul-Min Bae
  • Jae Sang Lee
  • Dong-Woo Suh


Changes in microstructure and mechanical properties of medium-carbon spring steel during austempering were investigated. After austempering for 1 h at 290 °C or 330 °C, the bainite transformation stabilized austenite, and microstructure consisting of bainitic ferrite and austenite could be obtained after final cooling; the retained austenite fraction was smaller in the alloy austempered at 290 °C because carbon redistribution between bainitic ferrite and austenite slowed as the temperature decreased, and thereby gave persistent driving force for the bainite transformation. The products of tensile strength and reduction of area in the austempered alloy were much larger in the austempered steel than in quenched and tempered alloy, mainly because of significant increase in reduction of area in austempered alloy.


Bainite Spring steel Austempering Tensile strength Reduction of area 


  1. 1.
    S.J. Matas, R.F. Hehemann, The structure of bainite in hypoeutectoid steels. Trans. Metall. Soc AIME 221(1), 179–185 (1961)Google Scholar
  2. 2.
    R.L. Houillier, G. Begin, A. Dube, Study of peculiarities of austenite during formation of bainite. Metall. Trans. 2(9), 2645–2653 (1971)CrossRefGoogle Scholar
  3. 3.
    F.G. Caballero, H.K.D.H. Bhadeshia, K.J.A. Mawella, D.G. Jones, P. Brown, Design of novel high strength bainitic steels: part 1. Mater. Sci. Technol. 17(5), 512–516 (2001)CrossRefGoogle Scholar
  4. 4.
    F.G. Caballero, H.K.D.H. Bhadeshia, K.J.A. Mawella, D.G. Jones, P. Brown, Design of novel high strength bainitic steels: part 2. Mater. Sci. Technol. 17(5), 517–522 (2001)CrossRefGoogle Scholar
  5. 5.
    F. Perrad, C. Mendibide, N. Yoshihara, Y. Namimura and N. Ibaraki, High strength spring steels with improved ductility and corrosion resistance. International Conference on Steels in Cars and Trucks, pp. 106–113 (2008)Google Scholar
  6. 6.
    F. Perrad, F. Charvieux and J. Languillaume, A new spring steel with improved ductility dedicated for high strength parabolic leaf springs. 2nd International Conference Super-High Strength Steels, Peschiera del Garda (2010)Google Scholar
  7. 7.
    T. Fukuzumi, S. Komazaki, T. Misawa, Hydrogen embrittlement and corrosion fatigue caused by pitting corrosion of spring steels for automobile with improved pitting corrosion resistance by alloying elements and chemical passivation treatment. J. Iron Steel Inst. Jpn. 88(2), 81–87 (2002)CrossRefGoogle Scholar
  8. 8.
    G.E. Hollox, R.A. Hobbs, J.M. Hampshire, Lower bainite bearings for adverse environments. Wear 68(2), 229–240 (1981)CrossRefGoogle Scholar
  9. 9.
    F.C. Akbasoglu, D.V. Edmonds, Rolling contact fatigue and fatigue crack propagation in 1C-1.5 Cr bearing steel in the bainitic condition. Metall. Trans. A 21(3), 889–893 (1990)CrossRefGoogle Scholar
  10. 10.
    N. Luzginova, L. Zhao, J. Sietsma, Evolution and thermal stability of retained austenite in SAE 52100 bainitic steel. Mater. Sci. Eng. A 448(1), 104–110 (2007)CrossRefGoogle Scholar
  11. 11.
    J. Chakraborty, D. Bhattacharjee, I. Manna, Austempering of bearing steel for improved mechanical properties. Scr. Mater. 59(2), 247–250 (2008)CrossRefGoogle Scholar
  12. 12.
    J. Chakraborty, D. Bhattacharjee, I. Manna, Development of ultrafine bainite + martensite duplex microstructure in SAE 52100 bearing steel by prior cold deformation. Scr. Mater. 61(6), 604–607 (2009)CrossRefGoogle Scholar
  13. 13.
    W.F. Smith, Structure and Properties of Engineering Alloys (McGraw-Hill, New York, 1993), p. 75Google Scholar
  14. 14.
    J.L. Paez, F. Fuentes, A. Battegliese, Isothermal treatment of SAE92XX type high silicon steels. Rev. Metal. 32(1), 3–9 (1996)CrossRefGoogle Scholar
  15. 15.
    J.A. Cruz Jr., T.F.M. Rodrigues, V.D.C. Viana, H. Abreu, D.B. Santos, Influence of temperature and time of austempering treatment on mechanical properties of SAE 9254 commercial steel. Steel Res. Int. 83(1), 22–31 (2012)CrossRefGoogle Scholar
  16. 16.
    J.A. Cruz Jr., D.B. Santos, Effect of tempering temperature on isothermal decomposition product formed below Ms. J. Mater. Res. Technol. 2(2), 93–99 (2013)CrossRefGoogle Scholar
  17. 17.
    H.M. Rietveld, Line profiles of neutron powder-diffraction peaks for structure refinement. Acta Crystallogr. A 22(1), 151–152 (1967)CrossRefGoogle Scholar
  18. 18.
    ASTM Standard E8/E8M (2004)Google Scholar
  19. 19.
    W.H. Bragg, W.L. Bragg, The reflection of X-rays by crystals. Proceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character, vol. 88, 605, pp. 428–438 (1913)Google Scholar
  20. 20.
    S.H. Kim, D.H. Kim, K.C. Hwang, S.B. Lee, S.K. Lee, H.U. Hong, D.W. Suh, Heat treatment response of TiC-reinforced steel matrix composite. Met. Mater. Int. 22(5), 935–941 (2016)CrossRefGoogle Scholar
  21. 21.
    N. Ridley, H. Stuart, L. Zwell, Lattice parameters of Fe-C austenites at room temperature. Trans. Met. Soc. AIME 245(8), 1834–1836 (1969)Google Scholar
  22. 22.
    C.S. Roberts, Effect of carbon on the volume fractions and lattice parameters of retained austenite and martensite. Trans. AIME 197(2), 203–204 (1953)Google Scholar
  23. 23.
    J.H. Jang, H.K.D.H. Bhadeshia, D.W. Suh, Solubility of carbon in tetragonal ferrite in equilibrium with austenite. Scr. Mater. 68(3), 195–198 (2013)CrossRefGoogle Scholar
  24. 24.
    B.C. De Cooman, K. Findley, Introduction to the Mechanical Behavior of Steel (AIST, Warrendale, 2016), pp. 209–215Google Scholar
  25. 25.
    C. Garcia-Mateo, F.G. Caballero, Ultra-high-strength bainitic steels. ISIJ 45(11), 1736–1740 (2005)CrossRefGoogle Scholar
  26. 26.
    A. Fallahi, Microstructure-properties correlation of dual phase steels produced by controlled rolling process. Mater. Sci. Technol. 18(5), 451–454 (2002)Google Scholar
  27. 27.
    N. Fonstein, M. Kapustin, N. Pottore, I. Gupta, O. Yakubovsky, Factors that determine the level of the yield strength and the return of the yield-point elongation in low-alloy ferrite-martensite steels. Phys. Met. Metallogr. 104(3), 315–323 (2007)CrossRefGoogle Scholar
  28. 28.
    G.E. Dieter, Mechanical Metallurgy (McGraw-Hill, New York, 1976), p. 343Google Scholar
  29. 29.
    N. Fonstein, Advanced High Strength Sheet Steels: Physical Metallurgy, Design, Processing, and Properties (Springer, Berlin, 2015), pp. 97–108CrossRefGoogle Scholar
  30. 30.
    W. Sha, Steels: From Materials Science to Structural Engineering (Springer, Berlin, 2016), pp. 27–58Google Scholar
  31. 31.
    H.K.D.H. Bhadeshia, D.V. Edmonds, Bainite in silicon steels: new composition–property approach part 1. Met. Sci. 17(9), 411–419 (1983)CrossRefGoogle Scholar

Copyright information

© The Korean Institute of Metals and Materials 2018

Authors and Affiliations

  • Seong Hoon Kim
    • 1
  • Kwan-Ho Kim
    • 2
  • Chul-Min Bae
    • 2
  • Jae Sang Lee
    • 1
  • Dong-Woo Suh
    • 1
  1. 1.Graduate Institute of Ferrous TechnologyPOSTECHPohangKorea
  2. 2.Technical Research LaboratoriesPOSCOPohangKorea

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