, Volume 7, Issue 1, pp 193–200 | Cite as

Study of the Effect of Boron on The Decomposition of Austenite

  • C. R. Simcoe
  • A. R. Elsea
  • G. K. Manning


Boron increases the hardenability of hypoeutectoid steels by decreasing the nucleation rate of ferrite and bainite. It is postulated that concentrations of lattice imperfections, such as exist at the grain boundaries, furnish the necessary energy for nucleus formation. Boron, because of its atomic diameter, will concentrate at lattice imperfections where sites of suitable size are present. Boron will decrease the energy of these local areas by occupying these sites. This mechanism accounts for the large increase in hardenability observed with small amounts of boron. The loss of the boron hardenability effect and the boron precipitate formation are explained on the basis of increased concentration of boron at the grain boundaries either with increasing boron content of the material or with increasing temperature.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    R. F. Mehl: The Decomposition of Austenite by Nucleation and Growth Process. Journal Iron and Steel Institute (1948) 159, p. 113.Google Scholar
  2. 2.
    Metals Handbook. (1948) Cleveland. ASM.Google Scholar
  3. 3.
    G. D. Rahrer and C. D. Armstrong: The Effect of Carbon Content on the Hardenability of Boron Steels. Trans. ASM (1948) 40, p. 1099.Google Scholar
  4. 4.
    R. A. Grange and T. M. Garvey: Factors Affecting the Hardenability of Boron-Treated Steels. Trans. ASM (1946) 37, p. 136.Google Scholar
  5. 5.
    R. F. Mehl and A. Dube: The Eutectoid Reaction. Phase Transformations in Solids. New York. John Wiley & Sons Inc.Google Scholar
  6. 6.
    W. A. Johnson and R. F. Mehl: Reaction Kinetics in Processes of Nucleation and Growth. Trans. AIME (1939) 135, p. 416.Google Scholar
  7. 7.
    T. G. Digges, C. R. Irish, and N. W. Carwile: Effect of Boron on the Hardenability of High-Purity Alloys and Commercial Steels. Journal of Research National Bureau of Standards (R. P. 1938) p. 41; (1948) p. 545.Google Scholar
  8. 8.
    J. E. Dorn, E. P. De Garmo, and A. E. Flanegan: Nucleation and Growth Rates of Pearlite. Trans. ASM (1941) 29, p. 1022.Google Scholar
  9. 9.
    R. Smoluchowski: Nucleation Theory. Phase Trans formations in Solids. (1951) p. 149. New York. John Wiley & Sons Inc.Google Scholar
  10. 10.
    A. H. Cottrell: Theoretical Structural Metallurgy. (1948) London. Arnold.Google Scholar
  11. 11.
    M. Volmer: Kenetik det Phasenbildung. (1939) Dresden. Steinkopff.Google Scholar
  12. 12.
    R. Becker: Annalen der Physik Leipzig (1938) 32, p. 128.CrossRefGoogle Scholar
  13. 13.
    R. Becker: Proceedings Physical Society (1940) 52, p. 71.CrossRefGoogle Scholar
  14. 14.
    C. S. Barrett: Structure of Metals (1952) New York. McGraw-Hill Book Co. Inc.Google Scholar
  15. 15.
    W. Hume-Rothery: The Structure of Metals and Alloys. (1945) London. Institute of Metals.MATHGoogle Scholar

Copyright information

© The Minerals, Metals & Materials Society 1955

Authors and Affiliations

  • C. R. Simcoe
    • 1
  • A. R. Elsea
    • 1
  • G. K. Manning
    • 1
  1. 1.Battelle Memorial InstituteColumbusUSA

Personalised recommendations