Skip to main content
SpringerLink
Log in

The effect of austenitizing temperature on the microstructure and mechanical properties of as-quenched 4340 steel

  • Published:
Metallurgical transactions Aims and scope Submit manuscript

Abstract

The effect of austenitizing temperature on both the plane strain fracture toughness,KIC, and the microstructure of AISI 4340 was studied. Austenitizing temperatures of 870 and 1200°C were employed. All specimens austenitized at 1200°C were furnace cooled from the higher austenitizing temperature and then oil quenched from 870°C. Transmission electron microscopy revealed an apparent large increase in the amount of retained austen-ite present in the specimens austenitized at the higher temperature. Austenitizing at 870°C resulted in virtually no retained austenite; only minor amounts were found sparsely scat-tered in those areas examined. A considerably altered microstructure was observed in specimens austenitized at 1200°C. Fairly continuous 100 to 200Å thick films of retained austenite were observed between the martensite laths throughout most of the area exam-ined. Additionally, specimens austenitized at 870°C contained twinned martensite plates while those austenitized at 1200°C showed no twinning. Plane strain fracture toughness measurements exhibited an approximate 80 pct increase in toughness for specimens austen-itized at 1200°C compared to those austenitized at 870°C. The yield strength was unaffected by austenitizing temperature. The possible role of retained austenite and the elimination of twinned martensite in the enhancement of the fracture toughness of those specimens austen-itized at the higher temperature will be discussed.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

References

  1. V. F. Zackay, E. R. Parker, R. D. Goolsby, and W. E. Wood:NaturePhys. Sci., 1972, vol. 236(68), p. 108.

    CAS  Google Scholar 

  2. D. Huang and G. Thomas:Met. Trans., 1971, vol. 2, p. 1587.

    Article  CAS  Google Scholar 

  3. R. Clark: M.S. Thesis, University of California, Berkeley, California, 1973, LBL-1801.

  4. W. W. Gerberich and J. P. Birat:Int. J. Fract. Mech., 1971, vol. 7, p. 108.

    Article  Google Scholar 

  5. S. D. Antolovich and B. Singh:Met. Trans., 1971, vol. 2, p. 2135.

    Article  CAS  Google Scholar 

  6. Annual Book of ASTM Standards (American Society for Testing and Ma- terials), Philadelphia, 1971, vol. 31, p. 911.

  7. J. E. Srawley and B. Gross:Mater. Res. Stand., 1967, vol. 7, p. 155.

    Google Scholar 

  8. J. R. Low, Jr.:Eng. Fract. Mech., 1968, vol. 1, p. 47.

    Article  CAS  Google Scholar 

  9. O. Johari and G. Thomas:Trans. ASM, 1965, vol. 58, p. 563.

    CAS  Google Scholar 

  10. J. A. McMahon and G. Thomas: “Development of Economical, Tough, Ultra- High-Strength Fe-Cr-C Steels,” LBL-1490, April 1973.

  11. P. M. Kelly and J. Nutting:J. Iron Steel Inst, 1961,vol. 197, p. 199.

    Google Scholar 

  12. M. Bevis, P. C. Rowlands, and A. F. Acton:Trans. TMS-AIME, 1968, vol. 242, p. 1555.

    CAS  Google Scholar 

  13. G. Krauss and W. Pitsch:Acta Met., 1964, vol. 12, p. 278.

    Article  CAS  Google Scholar 

  14. A. Gilbert, G. T. Hahn, C. N. Reid, and B. A. Wilcox:Acta Met, 1964, vol. 12, p. 754.

    Article  Google Scholar 

  15. D. Webster:Tram. ASM, 1968, vol. 61, p. 816.

    Google Scholar 

  16. D. Webster:Met. Trans., 1971, vol. 2, p. 1857.

    Article  CAS  Google Scholar 

  17. D. Webster:Met. Trans., 1971, vol. 2, p. 2097.

    Article  CAS  Google Scholar 

  18. P. Babu: unpublished results, University of California, Berkeley, California.

  19. E. M. Breinan and G. S. Ansell:Met. Trans., 1970, vol. 1, p. 1513.

    Article  CAS  Google Scholar 

  20. R. O. Ritchie, J. F. Knott, and L. C. E. Geniets: Third Intl. Conf. on the Strength of Metals and Alloys, Cambridge, England, 124, August 1973.

Download references

Author information

Authors and Affiliations

  1. University of California, 94720, Berkeley, California

    G. Y. Lai (Research Engineer), R. A. Clark (Graduate Student), V. F. Zackay (Professors of Metallurgy Department of Materials Science) & E. R. Parker (Engineering, College of Engi-neering)

  2. Oregon Graduate Center, Portland, Oregon

    W. E. Wood (Assistant Professor)

Authors
  1. G. Y. Lai
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. W. E. Wood
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. R. A. Clark
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. V. F. Zackay
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. E. R. Parker
    View author publications

    You can also search for this author in PubMed Google Scholar

Rights and permissions

Reprints and permissions

About this article

Cite this article

Lai, G.Y., Wood, W.E., Clark, R.A. et al. The effect of austenitizing temperature on the microstructure and mechanical properties of as-quenched 4340 steel. Metall Trans 5, 1663–1670 (1974). https://doi.org/10.1007/BF02646340

Download citation

  • Received:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF02646340

Keywords

Search

Navigation