The invention provides a medium temperature deformation nanometer
austenite enhanced plasticized steel and a preparation method thereof, belonging to the technical field of high-strength high-
plasticity automobile steel sheet materials, section bars and rods and wires. The steel comprises the following chemical components by
mass: 0.03 to 0.39 wt% of C, 2.0 to 9.0 wt% of Mn, 0 to 2.0 wt% of Al, 0 to 2.0 wt% of Si, 0 to 2.0 wt% of Cr, no more than 0.020 wt% of P and no more than 0.02 wt% of S, with the balance being Fe and unavoidable impurities. The steel may further comprise one or more elements selected from the group consisting of 0.1 to 3.0 wt% of Ni, 0.1 to 0.8 wt% of Mo, 0.5 to 2.0 wt% of Cu, 0.0005 to 0.005 wt% of B, 0.02 to 0.10 wt% of Nb, 0.002 to 0.25 wt% of N, 0.05 to 0.25 wt% of Ti, 0.02 to 0.25 wt% of V, 0.002 to 0.005 wt% of RE and 0.005 to 0.03 wt% of Ca. The invention has the following advantages: sizes of
austenite and ferrite of the steel are in a range of 50 to 250 nm; low cost, easy production, high strength and high
plasticity are realized; the steel has yield strength of 0.6 to 1.3 GPa, tensile strength of 1.0 to 1.5 GPa and
plasticity of 20 to 50% and has good low-temperature
toughness.