Thermal Stability of the Microstructure and Mechanical Properties of the Ferritic-Martensitic Steel EK-181

Resumo

Thermal stability of the microstructure and high-temperature mechanical properties of the low-activate 12% Cr ferritic-martensitic steel EK-181 are studied at temperatures from 700 to 800°C. It is shown that after traditional heat treatment and annealing at temperatures from 700 to 800°C, the ferritic-martensitic structure of the steel is retained and the density of coarse-dispersed M₂₃C₆ particles is increased. After annealing at T = 800°C, the initial recrystallization stages with the formation of new submicrocrystalline ferritic grains are detected. An increase in the annealing temperature from 700 to 800°C leads to a decrease in the strength properties of the steel. Wherein, the character of the temperature dependence of the strength at temperatures from 700 to 800°C is similar to that observed at lower temperatures (from 500 to 700°C).