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

• Main Authors: Tatyana MECHKAROVA, Yaroslav ARGIROV, Daniela SPASOVA, Aneliya STOYANOVA
• Format: Article
• Language: English
• Published: Galati University Press 2021-03-01
• Series: The Annals of “Dunarea de Jos” University of Galati. Fascicle IX, Metallurgy and Materials Science
• Subjects: nitric ferrite; aging; gas carbonitriding; micro-hardness; X-ray structural analysis
• Online Access: https://www.gup.ugal.ro/ugaljournals/index.php/mms/article/view/4319

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.