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.
Similar content being viewed by others
References
G.N. Goller and W.C. Clark, Jr.:Iron Age, 1950, vol. 165, pp. 86–89.
K.J. Irvine, D.T. Llewellyn, and F.B. Pickering:J. Iron Steel Inst., London, 1959, vol. 192, pp. 218–38.
Armco Steel Product Data Report No. S-24, Armco, Inc., Middletown, OH, 1986.
V. Seetharaman, M. Sundararaman, and R. Krishnan:Mater. Sci. Eng., 1981, vol. 47, pp. 1–11.
Metals Handbook—Properties and Selection: Iron, Steels, and High Performance Alloys, ASM, Metals Park, OH, 1990, vol. 1, p. 864.
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.
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.
D. Peckner and I.M. Bernstein:Handbook of Stainless Steels, McGraw-Hill, New York, NY, 1977, pp. 1–18.
H.J. Rack and D. Kalish:Metall. Trans., 1974, vol. 5, pp. 1595–1605.
Aerospace Material Specification AMS-5412, SAE International, Warrendale, PA, 1990, pp. 1-8.
D.J. Rossi and J.D. Rossi:Adv. Mater. Proc, 1987, vol. 3, pp. 45–47.
E.L. AuBuchon and R.V. London:Met. Progress, 1981, May, pp. 35-37.
D.L. Williamson, F.M. Kustas, D.F. Fobare, and M.S. Misra:J. Appl. Phys., 1986, vol. 60, pp. 1493–1500.
D.L. Williamson, R.G. Schupmann, J.P. Materkowsi, and G. Krauss:Metall. Trans. A, 1979, vol. 10A, pp. 379–82.
W.F. Chambers: “SandiaTASKS: a Subroutined Electron Microprobe Automation System,≓ Sandia Report No. SAND85-2037, Sandia National Laboratories, Albuquerque, NM, 1985.
M.J. Cieslak, C.R. Hills, P.F. Hlava, and S.A. David:Metall. Trans. A, 1990, vol. 21A, pp. 2465–75.
U.K. Viswanathan, S. Banerjee, and R. Krishnan:Mater. Sci. Eng., 1988, vol. A104, pp. 181–89.
J.C. Mabon, A.D. Romig, Jr., and C.E. Fiori:Anal. Chem., in press.
V.K. Vasudevan, S.J. Kim, and C.M. Wayman:Metall. Trans. A, 1990, vol. 21A, pp. 2655–68.
H. Brooks:Metal Interfaces, ASM, Metals Park, OH, 1952, p. 20.
K.E. Easterling and P.R. Swann:The Mechanism of Phase Transformations in Crystalline Solids, Monograph 33, Institute of Metals, London, 1969, p. 152. $
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Hochanadel, P.W., Edwards, G.R., Robino, C.V. et al. Heat treatment of investment cast PH 13-8 Mo stainless steel: Part I. Mechanical properties and microstructure. Metall Mater Trans A 25, 789–798 (1994). https://doi.org/10.1007/BF02665455
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF02665455