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 M 3 C are formed within the temperature range (500–600) °C. Formation of the stable phases М 23 С 6 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 (⩽10 nm) of vanadium carbonitride V(CN).