INFLUENCE OF TIME-TEMPERATURE PARAMETERS OF LONG-DURATION EXPOSURE ON TRANSFORMATIONS IN STRUCTURAL STEELS (review)

Low-temperature nitriding of steels is usually carried out in the temperature range of development of reversible temper brittleness. The holding time at these temperatures significantly exceeds the holding time during normal tempering, which can negatively affect the properties of steel. The article considers theories that explain the processes occurring in steels in the temper brittleness temperature range. It may be concluded that views linking the embrittlement of steel with alloying elements such as nickel in its content are not confirmed by the experiments; at the same time ideas based on classical views about the diffusion of chemical elements explain the processes in steel better.