Preoxidation prior to gas carburizing: Theory and its effect on pyrowear ® 53 alloy
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The absorption of carbon during gas carburizing of steel components is reviewed based on thermodynamic and kinetic considerations. The effects of chromium and silicon on carbon absorption are reviewed based on the thermodynamics of passive film formation in the presence of a carburizing gas. Finally, the merits associated with the use of preoxidation treatments prior to gas carburizing are discussed and the results of an in-depth analysis performed on carbon absorption in Pyrowear®1 53 alloy are presented based on preoxidation temperature.
Maximum carbon absorption was observed when using a preoxidation temperature of approximately 700/927° C (1292/1700° F) prior to carburizing Pyrowear 53 alloy at 927° C (1700° F) for 7.5 hr at a carbon potential of 1.16-1.19 using a 40% N2, 40% H2, and 20% CO endothermic carrier gas and vaporized methanol. This effect is believed to be related to the thickness of the oxide layer and to the roughness of the oxide/metal interface.
KeywordsAustenite Carbon Absorption Carbon Potential Surface Oxide Layer Furnace Atmosphere
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- 1.G. Krauss: “Principles of Heat Treatment of Steel,” p. 252, Am. Soc. Met., Metals Park, Ohio, 1980.Google Scholar
- 2.P.R. Patel: Bell Helicopter Corp., Forth Worth, Texas, unpublished research October 31, 1986.Google Scholar
- 3.Metals Handbook, 9th ed., Vol. 4, pp. 135–175, Am. Soc. Met., Metals Park, Ohio, 1981.Google Scholar
- 4.R.L. Davis,Met. Prog., 1969, vol. 96, pp. 99–102.Google Scholar
- 5.Carburizing and Carbonitriding, ASM Committee on Gas Carburizing, Am. Soc. Met., Metals Park, Ohio, 1977.Google Scholar
- 6.R. Collin, S. Gunnarson, and D. Thulin,J. Iron Steel Inst., 1972, vol. 210, pp. 785–789.Google Scholar
- 7.T. Ellis,J. Iron Steel Inst., 1963, vol. 201, pp. 582–587.Google Scholar
- 8.F. Neumann and B. Person,Härt.-Techn. Mitt., 1968, vol. 203, p. 296.Google Scholar
- 9.F.J. Harvey,Met. Trans., 1978, vol. 9A, pp. 1507–1513.Google Scholar
- 10.R. Collin, “Heat Treatment ’73,” proceedings of a conference, London, Dec. 1973, pp. 121–124, Met. Soc, London (1975).Google Scholar
- 11.R. Collin, M. Brachaczek, and D. Thulin,J. Iron Steel Inst., 1969, vol. 207, pp. 1122–1128.Google Scholar
- 12.R. Colin, S. Gunnarson, and D. Thulin,J. Iron Steel Inst., 1972, vol. 210, pp. 777–784.Google Scholar
- 13.R.A. Perkins, “Behavior of High Temperature Alloys in Aggressive Environments,” proceedings of the international conference Oct. 1979, pp. 617–645, Met. Soc, London (1980).Google Scholar
- 14.N.M. Levtonova, K.I. Cheskis, and A.F. Mikhailova,Met. Sci. Heat. Treat., 1976, vol. 18, pp. 433–434.Google Scholar
- 15.R.J. Cunningham, and W. Lieberman, U.S. Patent 3,885,995, May 27, 1975.Google Scholar
- 16.P.R. Patel, Inter-Office Memorandum, 81:PRP:mw-1175, Bell Helicopter Textron, June 24, 1986.Google Scholar
- 17.J.I. Goldstein, D.E. Newbury, P. Echlin, D.C. Joy, C. Fiori, and E. Lifshin, “Scanning Electron Microscopy and X-Ray Microanalysis,” pp. 306–308, Plenum Press, New York, 1984.Google Scholar
- 18.The Making, Shaping and Treating of Steel, 9th ed., pp. 297–298, United States Steel Corp., Pittsburgh, 1971.Google Scholar