Исследование возможностей повышения рабочих температур ферритно-мартенситной стали ЭК-181 с помощью высокотемпературной термомеханической обработки

Abstract

High-temperature (T=650-800°С) mechanical properties of ferritic-martensitic steel EK-181 after traditional heat treatment (normalized and tempered, N&T) and high-temperature thermomechanical treatment (HTMT) were studied. It is shown that at high test temperatures HTMT leads to an increase in the strength properties of the steel relative to N&T. At tension temperature Т=720 °С the yield strength of the steel after HTMT is higher than the corresponding values after N&T at a temperature Т = 650 °С. The studies of the microstructure of steel after HTMT have shown that such treatment leads to an increase in the dislocation density and in dispersion and volume fraction of nanoscale particles of vanadium carbonitride V (C, N). Such particles are capable to provide thermal stability of a microstructure and enhanced values of long-term hightemperature strength of the steel. This modification of the structural and phase state of the steel can provide an increase in the expected operating temperatures.