The stability of austenite in tensile deformation and its relation to a nitriding treatment in precipitation hardened stainless steel

Akira Ichikawa, Masatoshi Aramaki, Osamu Furukimi

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Two kinds of specimens of 17Cr-4.5Ni precipitation-hardened stainless steel were examined; one was treated in an ammonia decomposition gas atmosphere (nitriding gas) at 1338K for 0.6ks, and another one was no-nitriding. Tensile tests were performed using the above-mentioned specimens. The amount of austenite phase of specimens at various strain rates was quantified by means of X-ray diffraction. Although the specimen treated in nitriding gas exhibits about 50% strain in the tensile test, it does not show transformation-induced plasticity (TRIP) phenomenon. In contrast, the no-nitriding specimen, against the strain caused TRIP. Nitrogen gas in nitriding treatment increases the amount of nitrogen up to 0.03mass%. Most of the nitrogen was found to exist as solute atoms in the specimen. The specimen without TRIP exhibits a tensile strength of 1080MPa and an elongation of 49%. On the other hand, the no-nitriding specimen exhibits a tensile strength of 1170MPa and an elongation of 27%. Therefore, the former showed much higher deformation energy than the latter. This investigation provides evidence that the austenite phase of precipitation-hardened stainless steel is stabilized by nitrogen that is an austenite former, so martensite transformation is inhibited, and thus deformation energy increased.

Original languageEnglish
Title of host publicationProceedings of the 17th IFHTSE Congress
PublisherThe Japan Society for Heat Treatment (JSHT)
Pages506-509
Number of pages4
Volume2
ISBN (Electronic)9780000000002
Publication statusPublished - 2008
Event17th International Federation for Heat Treatment and Surface Engineering Congress 2008, IFHTSE 2008 - Kobe, Japan
Duration: Oct 26 2008Oct 28 2008

Other

Other17th International Federation for Heat Treatment and Surface Engineering Congress 2008, IFHTSE 2008
CountryJapan
CityKobe
Period10/26/0810/28/08

All Science Journal Classification (ASJC) codes

  • Surfaces, Coatings and Films
  • Condensed Matter Physics
  • Mechanics of Materials

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    Ichikawa, A., Aramaki, M., & Furukimi, O. (2008). The stability of austenite in tensile deformation and its relation to a nitriding treatment in precipitation hardened stainless steel. In Proceedings of the 17th IFHTSE Congress (Vol. 2, pp. 506-509). The Japan Society for Heat Treatment (JSHT).