Advertisement

Mechanism of the Effect of Cr on the Low-Temperature Toughness of High-Mn Austenitic Steels

  • K. S. Xue
  • J. J. Zhang
  • E. L. Rong
  • X. M. Jing
Part of the An International Cryogenic Materials Conference Publication book series (ACRE, volume 40)

Abstract

High-Mn steels with very stable austenitic structure exhibit a ductile-to-brittle transition at low temperature, which is accompanied by a change in the fracture mechanism from microvoid coalescence to intergranular fracture. Analyses by means of TEM-EDS and AES have shown that the low-temperature brittleness is caused by nonequilibrium segregation of Mn at grain boundaries. The addition of Cr greatly increases the low-temperature toughness. For the very stable, high-Mn austenitic steels, the effect of Cr cannot be explained on the basis of increased austenite stability or a change in its inhomogeneous deformation characteristic. It has been established by TEM-EDS analyses that Cr also segregates at the grain boundaries; therefore, it decreases the Mn segregation at the grain boundaries and increases the low-temperature toughness of high-Mn austenitic steels. For the 40Mn-7Cr steel, the relationship between the Cr and Mn contents at grain boundaries is: Mn = 47.99% - 0.88% Cr.

Keywords

Austenitic Steel Intergranular Fracture Manganese Austenitic Steel Nonequilibrium Segregation High Nitrogen Austenitic Stainless Steel 
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.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    K.S. Xue, “The Low Temperature Brittle Fracture of Austenitic Fe-Mn Alloys,” LBL20938, Lawrence Berkeley Laboratory, Berkeley (1986).Google Scholar
  2. 2.
    K.S. Xue, Z.L. Rong, X.M. Jing, and J.X. Fang, The improvement of low temperature toughness of high manganese austenitic steels, p. 501 in “Cryogenic Materials ‘88,” R.P. Reed, Z.S. Xing, and E.W. Collings, eds., International Cryogenic Materials Conference, Boulder, Colorado (1988).Google Scholar
  3. 3.
    R. Miura, H. Nakajima, Y. Takahashi, and K. Yoshida, 32Mn-7Cr austenitic steel for cryogenic applications, p. 245 in “Advances in Cryogenic Engineering—Materials,” vol. 30, A.F. clark and R.P. Reed, eds., Plenum Press, New York (1984).Google Scholar
  4. 4.
    Y. Tomota, H. Suzuki, and Y. Moriya, Ductile to brittle transition behavior in high-Mn steels, p. 446 in “International Congress on 5th Heat Treatment of Materials Proceedings,” vol. 1, Scientific Society of Mechanical Engineers, Budapest, Hungary (1986).Google Scholar
  5. 5.
    Y. Tomota, M. Strum, and J.W. Morris, Jr., The relationship between toughness and microstructure in Fe-high Mn binary alloy, Metall. Trans. A 18A: 1073 (1987).Google Scholar
  6. 6.
    T. Sakamoto, Y. Nakagawa, and I. Yamauchi, Effect of Mn on the cryogenic properties of high nitrogen austenitic stainless steels, p. 65 in “Advances in Cryogenic Engineering—Materials,” vol. 32, R.P. Reed and A.F. Clark, eds., Plenum Press, New York (1986).Google Scholar
  7. 7.
    Y. Tomota and S. Shibuki, Intergranular fracture in Fe-Mn austenitic alloys at 77 K, ISIJ Int. 30: 663 (1990).CrossRefGoogle Scholar
  8. 8.
    P. Doig and P.E.J. Flewtt, Nonequilibrium solute segregation to austenite grain boundaries in low alloy ferritic and austenitic steels, Metall. Trans. A 18A: 399 (1987).Google Scholar
  9. 9.
    R.G. Faulkner, Nonequilibrium grain boundary segregation in steels, p. 266 in “Advances in the Physical Metallurgy and Applications of Steels,” The Metals Society, London (1982).Google Scholar

Copyright information

© Springer Science+Business Media New York 1994

Authors and Affiliations

  • K. S. Xue
    • 1
  • J. J. Zhang
    • 1
  • E. L. Rong
    • 1
  • X. M. Jing
    • 1
  1. 1.Shanghai Research Institute of MaterialsShanghaiChina

Personalised recommendations