The effect of tempering temperature on the features of phase transformations in the ferritic–martensitic steel EK-181

Abstract

Using the methods of dilatometry and differential scanning calorimetry, critical points of phase transformations in the low-activation ferritic–martensitic steel EK-181 (RUSFER-EK-181) are identified. The characteristic temperature intervals of precipitation of carbide phases are revealed. It is shown that particles of the metastable carbide M3C are formed within the temperature range (500–600)°C. Formation of the stable phases М23С6 and V(CN) begins at the temperatures higher than Т=650°С. An important feature of microstructure after tempering at Т=720°С is high density of nanoparticles (⩽10nm) of vanadium carbonitride V(CN).