Metallurgical and Materials Transactions A

, Volume 25, Issue 4, pp 789–798 | Cite as

Heat treatment of investment cast PH 13-8 Mo stainless steel: Part I. Mechanical properties and microstructure

  • P. W. Hochanadel
  • G. R. Edwards
  • C. V. Robino
  • M. J. Cieslak
Mechanical Behaviour

Abstract

The microstructure of investment cast PH 13-8 Mo stainless steel heat-treated to various conditions was studied using light and electron microscopy, electron probe microanalysis, and Mössbauer spectroscopy. The mechanical properties were investigated by using uniaxial tensile testing, hardness testing, and Charpy impact testing. TheΒ-NiAl strengthening precipitates, though detectable by electron diffraction, were difficult to resolve by transmission electron microscopy (TEM) in specimens aged at low temperatures (566 °C and below). A high dislocation density was observed in the lath martensitic structure. The higher strength and lower ductility observed at low aging temperatures was attributed to both the high dislocation density and the precipitation ofΒ-NiAl. When samples were aged at high temperatures (> 566 °C), a lower dislocation density and a reverted austenite fraction on the order of 15 pct were observed. SphericalΒ-NiAl precipitates were observed in the overaged condition. The decrease in strength and corresponding increase in ductility observed in samples aged at temperatures above 566 °C were attributed to the reverted austenite and recovery. Mechanical properties were improved when the homogenizing temperature and time were increased. Electron probe microanalysis quantified the increased homogeneity realized by increasing homogenizing temperature and time. Elimination of the refrigeration step, which normally follows the solution treatment, did not degrade the mechanical properties. Mössbauer spectroscopy showed only minor decreases in the fraction of retained austenite when refrigeration followed the solution treatment.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    G.N. Goller and W.C. Clark, Jr.:Iron Age, 1950, vol. 165, pp. 86–89.Google Scholar
  2. 2.
    K.J. Irvine, D.T. Llewellyn, and F.B. Pickering:J. Iron Steel Inst., London, 1959, vol. 192, pp. 218–38.Google Scholar
  3. 3.
    Armco Steel Product Data Report No. S-24, Armco, Inc., Middletown, OH, 1986.Google Scholar
  4. 4.
    V. Seetharaman, M. Sundararaman, and R. Krishnan:Mater. Sci. Eng., 1981, vol. 47, pp. 1–11.CrossRefGoogle Scholar
  5. 5.
    Metals Handbook—Properties and Selection: Iron, Steels, and High Performance Alloys, ASM, Metals Park, OH, 1990, vol. 1, p. 864.Google Scholar
  6. 6.
    W.R. Cieslak, J.A. Brooks, and W.M. Garrison, Jr.:Advances in Welding Science and Technology, S.A. David, ed., ASM, Metals Park, OH, 1986, pp. 515–22.Google Scholar
  7. 7.
    M.J. Cieslak and S.A. David:Abstracts of Papers—69th American Welding Society Annual Meeting, Washington, DC, April 17-22, 1988, American Welding Society, Miami, FL, pp. 74–77.Google Scholar
  8. 8.
    D. Peckner and I.M. Bernstein:Handbook of Stainless Steels, McGraw-Hill, New York, NY, 1977, pp. 1–18.Google Scholar
  9. 9.
    H.J. Rack and D. Kalish:Metall. Trans., 1974, vol. 5, pp. 1595–1605.CrossRefGoogle Scholar
  10. 10.
    Aerospace Material Specification AMS-5412, SAE International, Warrendale, PA, 1990, pp. 1-8.Google Scholar
  11. 11.
    D.J. Rossi and J.D. Rossi:Adv. Mater. Proc, 1987, vol. 3, pp. 45–47.Google Scholar
  12. 12.
    E.L. AuBuchon and R.V. London:Met. Progress, 1981, May, pp. 35-37.Google Scholar
  13. 13.
    D.L. Williamson, F.M. Kustas, D.F. Fobare, and M.S. Misra:J. Appl. Phys., 1986, vol. 60, pp. 1493–1500.CrossRefGoogle Scholar
  14. 14.
    D.L. Williamson, R.G. Schupmann, J.P. Materkowsi, and G. Krauss:Metall. Trans. A, 1979, vol. 10A, pp. 379–82.Google Scholar
  15. 15.
    W.F. Chambers: “SandiaTASKS: a Subroutined Electron Microprobe Automation System,≓ Sandia Report No. SAND85-2037, Sandia National Laboratories, Albuquerque, NM, 1985.Google Scholar
  16. 16.
    M.J. Cieslak, C.R. Hills, P.F. Hlava, and S.A. David:Metall. Trans. A, 1990, vol. 21A, pp. 2465–75.Google Scholar
  17. 17.
    U.K. Viswanathan, S. Banerjee, and R. Krishnan:Mater. Sci. Eng., 1988, vol. A104, pp. 181–89.Google Scholar
  18. 18.
    J.C. Mabon, A.D. Romig, Jr., and C.E. Fiori:Anal. Chem., in press.Google Scholar
  19. 19.
    V.K. Vasudevan, S.J. Kim, and C.M. Wayman:Metall. Trans. A, 1990, vol. 21A, pp. 2655–68.Google Scholar
  20. 20.
    H. Brooks:Metal Interfaces, ASM, Metals Park, OH, 1952, p. 20.Google Scholar
  21. 21.
    K.E. Easterling and P.R. Swann:The Mechanism of Phase Transformations in Crystalline Solids, Monograph 33, Institute of Metals, London, 1969, p. 152. $Google Scholar

Copyright information

© The Minerals, Metals and Materials Society, and ASM International 1994

Authors and Affiliations

  • P. W. Hochanadel
    • 1
  • G. R. Edwards
    • 1
  • C. V. Robino
    • 2
  • M. J. Cieslak
    • 2
  1. 1.Center for Welding and Joining Research, Department of Metallurgical and Materials EngineeringColorado School of MinesGolden
  2. 2.Physical and Joining Metallurgy DepartmentSandia National LaboratoriesAlbuquerque

Personalised recommendations