High yield strength (710–862 MPa) ferritic microalloyed steels are developed through the combined contribution of Nb, Mo, V, and Cr microalloying and controlled thermomechanical treatment. Microstructures and mechanical properties are characterized using advanced microscopy techniques and uniaxial tensile testing. NbV carbonitrides with/without Mo (depending on steel composition) are formed in austenite and range from 30 to 70 nm in average diameter. However, V- and Cr-rich interphase (3–7 nm range) and random (1–6 nm range) precipitates are found in polygonal ferrite. An increase in rou...