Microstructures and mechanical properties of three medium-Mn steels processed via quenching and partitioning as well as austenite reversion heat treatments

In order to establish the processing conditions achieve target of tensile strength ∼1500 MPa with minimum retained austenite (RA) fraction 10% in hot-rolled 3–4%Mn medium Mn steels, three hot-deformed steels base composition Fe-0.3C–1Si-0.5Al (concentrations wt.%) and variable contents (3 or 4 wt%), Ni (1 2 Mo (0.2 0.4 wt%) V (0 0.2 were processed using both quenching partitioning (QP) reverse transformation (ART) treatments. Physical simulation experiments carried out small cylinders a thermomechanical simulator differences amounts, morphology stability RA established by X-ray diffraction electron probe microanalysis, besides standard material characterization techniques. Both processes provided relatively high fractions austenite; up 26 vol% QP route 49 ART treatment under specific conditions. These amounts comparable those predicted for thermodynamic equilibrium ThermoCalc software. The various was estimated terms average carbon RA. process had mostly blocky-like appearance while majority lath-like shaped. hardness measurements revealed that level structures higher than samples, possibly affected but more obviously as result martensite tempered at low temperatures treated structures. Preliminary properties measured on selected laboratory samples results analyzed based characteristics. preliminary indicated is achievable scale through routes.