Microstructures and mechanical properties of 60Si2CrVA steel by isothermal transformation at low temperature

A study is presented of the microstructures and mechanical properties of 60Si2CrVA steel subjected to isothermal transformation at 235 °C for 8 h and 270 °C for 3 h after austenizing at 1000 °C for 20 min. The microstructures of the steel after this treatment are composed of two phases, carbide-free bainitic ferrite and retained austenite, with lath- and film-like morphologies, respectively, and showing the features of low-temperature bainite. The corresponding mechanical properties are measured to be ∼1980 MPa of tensile strength and ∼9.5% of elongation for 235 °C-transformed sample, and ∼1880 MPa and ∼10.5% for 270 °C-transformed sample. The conventional lower bainite is not observed in the two isothermally transformed samples.