Metallurgical Transactions A

, Volume 7, Issue 6, pp 831–838 | Cite as

Evaluation of toughness in AISI 4340 alloy steel austenitized at low and high temperatures

  • Robert O. Ritchie
  • Benjamin Francis
  • William L. Server
Mechanical Behavior


It has been reported for as-quenched AISI 4340 steel that high temperature austenitizing treatments at 1200°C, instead of conventional heat-treatment at 870°C, result in a two-foldincrease in fracture toughness,K Ic, but adecrease in Charpy impact energy. This paper seeks to find an explanation for this discrepancy in Charpy and fracture toughness data in terms of the difference betweenK Ic and impact tests. It is shown that the observed behavior is independent of shear lip energy and strain rate effects, but can be rationalized in terms of the differing response of the structure produced by each austenitizing treatment to the influence of notch root radius on toughness. The microstructural factors which affect this behavior are discussed. Based on these and other observations, it is considered that the use of high temperature austenitizing be questioned as a practical heat-treatment procedure for ultrahigh strength, low alloy steels. Finally, it is suggested that evaluation of material toughness should not be based solely onK Ic or Charpy impact energy values alone; both sharp crack fracture toughness and rounded notch impact energy tests are required.


Fracture Toughness Charpy Impact Root Radius Sharp Crack Charpy Impact Energy 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    G. Y. Lai, W. E. Wood, R. A. Clark, V. F. Zackay, and E. R. Parker:Met. Trans., 1974, vol. 5, p. 1663.CrossRefGoogle Scholar
  2. 2.
    D. Dulieu: Discussion to paper by V. F. Zackay, E. R. Parker, and W. E. Wood;Proc. Third Intl. Conf. on the Strength of Metals and Alloys, vol. 2, p. 383, Institute of Metals/Iron and Steel Institute, Cambridge, England, Aug. 1973.Google Scholar
  3. 3.
    W. E. Wood, E. R. Parker, and V. F. Zackay: Rept. No. LBL-1474, Lawrence Berkeley Laboratory, University of California, Berkeley, Calif. 94720, May, 1973.Google Scholar
  4. 4.
    A. A. Anctil and E. B. Kula: unpublished research, Army Materials and Me- chanics Research Center, Watertown, Mass., 1975.Google Scholar
  5. 5.
    Annual Book of ASTM Standards (American Society for Testing and Materials), ASTM Standards E399-74, Philadelphia, 1974.Google Scholar
  6. 6.
    Annual Book of ASTM Standards, (American Society for Testing and Mater- ials), p. 276, ASTM Standards E23-72, Philadelphia, 1972.Google Scholar
  7. 7.
    W. L. Server and A. S. Tetelman:Eng. Fract. Mech., 1972, vol. 4, p. 367.CrossRefGoogle Scholar
  8. 8.
    W. L. Server, D. R. Ireland, and R. A. Wullaert: Dynatup Technical Rept. No. TR 74-29R, Effects Technology, Inc., Santa Barbara, California 93105, November 1974.Google Scholar
  9. 9.
    T. R. Wilshaw, A. Rau, and A. S. Tetelman:Eng. Fract. Mech., 1968, vol. 1, p. 191.CrossRefGoogle Scholar
  10. 10.
    J. Malkin and A. S. Tetelman:ibid, 1971, vol. 3, p. 151.Google Scholar
  11. 11.
    P. T. Heald, G. M. Spink, and P. J. Worthington:Mater. Sci. Eng., 1972, vol. 10, p. 129.CrossRefGoogle Scholar
  12. 12.
    S. Ensha and A. S. Tetelman: UCLA Tech. Rept., No. 14, UCLA-ENG-7435, SchoolofEngineeringandAppliedScience, University of California, Los Angeles, Calif. 90024, May 1974.Google Scholar
  13. 13.
    A. H. Cottrell:The Mechanical Properties of Matter, p. 365, John Wiley & Sons, New York, 1964.Google Scholar
  14. 14.
    A. S. Tetelman, T. R. Wilshaw, and A. Rau:Int. J. Fract. Mech., 1968, vol. 4, p. 147.Google Scholar
  15. 15.
    R. O. Ritchie, J. F. Knott, and J. R. Rice:J. Mech. Phys. Solids, 1973, vol. 21, p. 395.CrossRefGoogle Scholar
  16. 16.
    J. R. Rice and M. A. Johnson:Inelastic Behavior of Solids, M. F. Kanninenefal, eds., p. 641, McGraw Hill, New York, 1970.Google Scholar
  17. 17.
    J. R. Griffiths and D. R. J. Owen:J. Mech. Phys. Solids, 1971, vol. 19, p. 149.CrossRefGoogle Scholar
  18. 18.
    G. Chipperfield and J. F. Knott:Metals Technol., 1975, vol. 2, p. 45.Google Scholar
  19. 19.
    B. J. Schulz and J. McMahon, Jr.: ASTM STP No. 499. p. 104, American Society for Testing and Materials, 1972.Google Scholar
  20. 20.
    G. Clark, R. O. Ritchie, and J. F. Knott:Nature Phys. Sci., 1972. vol. 239, p. 104.Google Scholar
  21. 21.
    B. J. Schulz and J. McMahon, Jr.:Met. Trans., 1973, vol. 4, p. 2485.CrossRefGoogle Scholar
  22. 22.
    R.O. Ritchie and J. F. Knott:ibid, 1974, vol. 5. p. 782.Google Scholar
  23. 23.
    G. Thomas:Iron Steel International, 1973, vol. 46. p. 451.Google Scholar
  24. 24.
    G. Y. Lai:Mater. Sci. Eng., 1975. vol. 19, p. 153.CrossRefGoogle Scholar
  25. 25.
    W. E. Wood:Eng. Fract. Mech., 1975. vol. 7. p. 219.CrossRefGoogle Scholar
  26. 26.
    S. K. Das and G. Thomas:Trans. ASM, 1969. vol. 62. p. 659.Google Scholar
  27. 27.
    J. A. McMahon and G. Thomas:Proc. Third Intl. Conf. on the Strength of Metals and Alloys, vol. 1, p. 180. Institute of Metals/Iron and Steel Institute, Cambridge, England, Aug. 1973.Google Scholar
  28. 28.
    R. O. Ritchie, L. E. Geniets, and J. F. Knott:ibid, p. 124.Google Scholar
  29. 29.
    R. A. Clark and G. Thomas:Met. Trans. A, 1975, vol. 6A,p.969.Google Scholar
  30. 30.
    J. R. Rellick and J. McMahon, Jr.:Met. Trans., 1974, vol. 5, p. 2439.CrossRefGoogle Scholar
  31. 31.
    V. F. Zackay, E. R. Parker, R. D. Goolsby, and W. E. Wood:Nature Phys. Sci., 1972, vol. 236, p. 108.Google Scholar
  32. 32.
    T. Tom: D. Eng. Thesis, Rept. No. LBL-1856, Lawrence Berkeley Laboratory, University of California, Berkeley, Calif. 94720. Sept. 1973.Google Scholar

Copyright information

© The Metallurgical of Society of AIME 1976

Authors and Affiliations

  • Robert O. Ritchie
    • 1
  • Benjamin Francis
    • 2
  • William L. Server
    • 3
  1. 1.Department of Materials Science and Engineering, and Molecular and Materials Research DivisionLawrence Berkeley Laboratory, Uni- versity of CaliforniaBerkeley
  2. 2.Harvey Mudd CollegeClaremont
  3. 3.Fracture Control CorporationGoleta

Personalised recommendations