Vplyv teploty austenitizácie na kinetiku izotermického rozpadu austenitu v oceli 15020

Abstract

In the bachelor thesis, an analysis of the influence of temperature on the kinetics of isothermal decomposition of austenite in podeutectoid steel was performed. The theoretical part of the work described in the detail the phase and microstructural changes taking place in steels, austenitization and its kinetics, as well as IRA and ARA diagrams. In the practical part of the work, the kinetics of austenite decomposition in podeutectoid steel quality 15020 during the isothermal endurance at 750°C was studied, where the samples were austenitized at temperatures of 880°C and 950°C. The theoretical kinetic curves of austenite decay calculated by John-Mehl-Avrami relation were compared with the experimental results of the proportion and grain size of proeutectoid ferrite. It was concluded that at a higher austenitization temperature, the rate of heterogeneous nucleation of proutectoid ferrite is lower.