Microstructure of EK-181 ferritic-martensitic steel after heat treatment under various conditions

The effect of heat treatment conditions on the microstructure and phase composition of a lowactivated high-temperature ferritic-martensitic EK-181 steel (Fe-12Cr-2W-V-Ta-Ba) is studied. Additional thermal cycling about the austenite-martensite phase transition temperature between quenching and tempering hinders the formation of fine interstitial phases, decreases the phase transformation-induced hardening intensity, retards the formation of a substructure with continuous misorientations, and decreases the brittle-ductile transition temperature.