Warm deformation behavior of quenched medium carbon steel and its effect on microstructure and mechanical properties

The warm deformation behavior of quenched 0.45C steel was investigated, and the constitutive equation of the warm deformation was established. The effect of warm deformation on the microstructure and mechanical properties was analyzed. Results show that the ultrafine grain microstructure composed of submicron ferrite grains and nanoscale cementite particles can be created in the steel by quenching and warm deformation under moderate conditions. Compared to conventional quenching and high-temperature tempering, quenching and subsequently warm deformation at 600 °C can result in much higher tensile strength (861 MPa), nearly double the yield strength (777 MPa), and about the same total elongation (19.1%) and uniform elongation (9.3%).