Structural Changes of Nitrogen Ferrite After Aging in Temperature Interval up to 100 °С

  • Tatyana MECHKAROVA Technical University of Varna, Bulgaria
  • Yaroslav ARGIROV Technical University of Varna, Bulgaria
  • Daniela SPASOVA Technical University of Varna, Bulgaria
  • Aneliya STOYANOVA Technical University of Varna, Bulgaria
Keywords: nitric ferrite, aging, gas carbonitriding, micro-hardness, X-ray structural analysis


This paper aims to determine the extent of aging of nitrogen ferrite at temperatures below 100 °C and the structural and strength changes that occur in the process. The tests are carried out on samples of technically pure iron (Armco). The specimens are pre-deformed by tension and re-crystallisation heating to achieve a large-grain ferrite structure. A large-grained structure has been chosen to more accurately track the change in micro-hardness of the individual grains during the aging process. Nitric ferrite results from gas carbonitriding and subsequent hardening. Upon hardening, the samples are stored in a refrigerator, and then the surface layer formed is removed through electrochemical corrosion. Afterwards, aging heat treatment at temperatures below 100 °C is undertaken. After the aging process, micro-hardness of the individual grains is examined and X-ray structural analysis is performed.

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How to Cite
MECHKAROVA T, ARGIROV Y, SPASOVA D, STOYANOVA A. Structural Changes of Nitrogen Ferrite After Aging in Temperature Interval up to 100 °С. The Annals of “Dunarea de Jos” University of Galati. Fascicle IX, Metallurgy and Materials Science [Internet]. 15Mar.2021 [cited 24Jul.2021];44(1):28-3. Available from: