Metallurgical and Mechanical Investigation on Single-Step Quenching and Partitioning Thermal Treatments on Commercial Low Alloyed 30MnV6 Steel

Abstract

Characterization of the effect of different Quenching and Partitioning treatments on retained austenite stabilization, on the final microstructure, and on tensile properties was performed on 30MnV6 microalloyed steel. The amount of retained austenite and its location into the final microstructure were evaluated through X-ray diffraction and Electron Backscattered diffraction. Moreover, different initial microstructural conditions were employed to preliminarily investigate the effect of a starting mixed austenite–ferrite microstructure on the effectiveness of the treatment, and to tailor the material final tensile properties according to its actual utilization. Amounts of retained austenite between 4.5 and 6.3 pct were observed. High tensile properties were obtained, reaching 1675 MPa of UTS, with an improved elongation with respect to the reference quenched and tempered condition, which reached 14.8 pct. Hardenability is increased by the presence of retained austenite. Intercritical condition shows lower tensile strength but an increased uniform elongation with respect to the reference quenched and partitioned condition. Therefore, quenching and partitioning appears to be a promising treatment for the selected commercial steel.