Skip to main content
Article thumbnail
Location of Repository

Nitriding of aluminium-containing steels

By Abbas Abdul-Hussein


This thesis describes a study of the nitriding\ud behaviour of some aluminium-containing low alloy steels with\ud and without chromium. The main aim of the study has been\ud to establish the relationship between prior heat treatment\ud and nitriding process variables on the nitriding response of\ud the aluminium containing steels. Emphasis was placed on\ud establishing the metallography of the steels nitrided under\ud controlled conditions, using transmission electron microscopy of thin foils and carbon replicas, optical microscopy and microhardness measurements. A potentiostatic etching method was used for the extraction of carbides and nitrides, and those phases which were present were determined by X-ray diffraction and X-ray microanalysis.\ud \ud In addition to the known nitride phases, i. e. f. c. c\ud CrN and hexagonal A1N, another phase with a-Fe type d-spacing was observed, and subsequently identified as f. c. c. A1N of NaCl structure with a ti 4.05 A. This phase transforms to hexagonal A1N if the nitrided specimen is annealed at 700°C. The latter phase was found to be rich in silicon. Unlike CrN, the precipitation of A1N is greatly influenced by the nitriding temperature and the NH3 content of the gas mixture.\ud \ud The formation of the carburized layer depends on\ud the internal compressive stress of nitrided layer. The size\ud of the carbides is an impörtant factor in the formation of\ud this layer. Larger: carbides are more stable and less likely\ud to dissolve during nitriding. In bulk specimens, nitrided\ud in high NH3 content so as to form a white layer on the\ud surface, carbide concentration takes place under the white\ud layer.\ud \ud The effect of process variables on the fatigue resistance of nitrided steel has been investigated. Specimens of "Nitralloy" En41A have been gas nitrided under\ud controlled conditions to produce steep and shallow case-hardness profiles with and without white layer. The resultant fatigue properties have been related to the microstructure, hardness profile, residual stress and case depth. The fatigue resistance of the nitrided En41A steel depend on the residual stress level in the case, and to a certain extent on the microstructure of the nitrided layer.\ud Nitriding at 570°C produces low residual stress and also\ud causes embrittlement of the nitrided layer

Publisher: School of Chemical and Process Engineering (Leeds)
Year: 1984
OAI identifier:

Suggested articles


  1. (1928). A New Method of Case Hardening'.
  2. Advances in Material Research'
  3. (1946). American Society for Metal 'Symposium on Surface Stressing of Metals',
  4. (1929). American Society. for: Steel -Treating,
  5. (1952). Archive Eisench,
  6. British patent
  7. (1980). Characterization of nitrided alloy Steels",
  8. Chemical Metallurgy of Iron
  9. (1930). Comptes Rendues
  10. Cr-Mo Nitriding Steels with 2.5-3.5% Cr' Climax Molybdenum Co.
  11. (1975). Heat Treatment '73, The metal doi
  12. Heat treatment '73, The Metal Jack,
  13. (1978). Heat Treatment of Metals,
  14. Heat-treating and forging 1930,16,
  15. Kessho Kaiseki,
  16. (1976). Metal Progress,
  17. (1977). Metal technology
  18. (1943). Metal Treatment,
  19. (1974). Metallography and Heat Treatment of Metals,
  20. (1929). Nitriding Symposium,
  21. (1923). Nitrogen in Iron, Steel and Special Steels', Kruppsche Monatshaft,
  22. Patent 884,180,1908-and subsequent patents
  23. Physical Chem. of Metals'. doi
  24. (1979). Practical Metallurgy,
  25. (1970). Protective Coatings on Metals,
  26. (1959). Reducing Scuffing and Wear of Ferrous Materials', doi
  27. (1905). Revue de Metallurgie Memoirs
  28. (1948). Revue de Metallurgie,
  29. Revue Met.
  30. (1973). Symposium of physical Metallurgy, Edenhofer, B. Aspects of Surface Coating',
  31. (1950). Symposium: Fatigue and Fracture of Materials,
  32. Technique for Metal Research, Turkdogan,
  33. (1979). The effect of process variables on the nitriding behaviour of chromium steels',
  34. (1976). The Isolation and Determination Miyamoto, A. in Steel',
  35. (1973). thesis 'Nitriding of some chromium irons and Steels',

To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.