Journal of the Korean Society for Heat Treatment (열처리공학회지)

The Korean Society for Heat Treatment (한국열처리공학회)
권호 표지
DOI QR코드

DOI QR Code

Effects of C, Mo and Cr on Hardenability and Mechanical Properties of Boron-Bearing Steels

보론강의 경화능과 인장 특성에 미치는C, Mo, Cr의 영향

  • Yim, H.S. (Department of Materials Science and Engineering, Seoul National University of Science and Technology) ;
  • Jung, W.Y. (Department of Materials Science and Engineering, Seoul National University of Science and Technology) ;
  • Hwang, B. (Department of Materials Science and Engineering, Seoul National University of Science and Technology)
  • 임현석 (서울과학기술대학교 신소재공학과) ;
  • 정우연 (서울과학기술대학교 신소재공학과) ;
  • 황병철 (서울과학기술대학교 신소재공학과)
  • Received : 2012.08.02
  • Accepted : 2013.08.16
  • Published : 2013.09.30
Download PDF
⟨ Previous Next ⟩

Abstract

Hardenability and mechanical properties of boron-bearing steels containing C, Mo and Cr were investigated in this study. Using quench dilatometer, the steel specimens were cooled down to room temperature at different cooling rates to construct continuous cooling transformation diagrams and then the transformation products from austenite were examined. A critical cooling rate was introduced as an index to quantitatively evaluate the hardenability. The C addition to boron-bearing steels did not significantly affect hardenability compared to boron-free steels although it increases the hardenability. With the same content, the Mo addition largely increased the hardenability of boron-bearing steels than the Cr addition because it decreased both the transformation start and finish temperatures at low cooling rates. In particular, the Mo addition completely suppressed the formation of eutectoid ferrite even at the slow cooling rate of $0.2^{\circ}C/s$, whereas the Cr addition nearly suppressed it at the cooling rates above $3^{\circ}C/s$.

Keywords

References

  1. S. K. Banerji and J. E. Morral : Proc. Int. Symp. Boron in Steels, TMS-AIME, PA (1979).
  2. D. H. Werner : Boron and Boron Containing Steels, Verlag Stahleisen mbH, Dusseldorf (1995).
  3. D. V. Doane and J. S. Kirkaldy : Hardenability Concepts with Application to Steel, TMS-AIME, Warrendale, PA (1978).
  4. Ph. Maitrepierre, D. Thivellier and R. Tricot : Metall. Trans. A, 6 (1975) 287. https://doi.org/10.1007/BF02667283
  5. Front of Research on Behavior of Boron in Steels, Iron Steel Inst. Jpn. (2003).
  6. M. Ueno and T. Inoue : Trans. Iron Steel Inst. Jpn., 13 (1973) 210.
  7. H. Asahi : ISIJ Int., 42 (2002) 1150. https://doi.org/10.2355/isijinternational.42.1150
  8. B. Hwang, D. -W. Suh and S. -J. Kim : Scr. Mater., 64 (2011) 1118. https://doi.org/10.1016/j.scriptamat.2011.03.003
  9. L. Karlsson, H. Norden and H. Odelius : Acta Metall., 36 (1988) 1. https://doi.org/10.1016/0001-6160(88)90023-5
  10. X. L. He, Y. Y. Chu and J. J. Jonas : Acta Metall., 37 (1989) 147. https://doi.org/10.1016/0001-6160(89)90274-5
  11. S. Khare, K. Lee and H. K. D. H. Bhadeshia : Int. J. Mat. Res., 100 (2009) 11. https://doi.org/10.3139/146.101793
  12. K. A. Taylor : Metall. Trans. A, 23 (1992) 107. https://doi.org/10.1007/BF02660858
  13. Standard Test Methods for Determining Hardenability of Steel, ASTM International, Designation: A 255-02 (2002).
  14. G. Krauss, Principles of Heat Treatment of Steel, ASM Intl. (1989).
  15. J. C. Ion and L. M. Anisdahl : J. Mat. Proc. Tech., 65 (1997) 261. https://doi.org/10.1016/S0924-0136(96)02413-2
  16. B. C. De Cooman, J. G. Speer, I. Y. Pyshmintsev and N. Yoshinaga : Materials Design - The Key to Modern Steel Products, GRIPS media GmbH (2007).
  17. D. J. Mun, E. J. Shin, Y. W. Choi, J. S. Lee and Y. M. Koo : Mater. Sci. Eng. A, 545 (2012) 214. https://doi.org/10.1016/j.msea.2012.03.047