The application belongs to the technical field of
metallurgy, and more particularly relates to a high-
plasticity 3GPa-grade medium-low
alloy steel and a preparation method thereof. The high-
plasticity 3GPa-grade medium-low
alloy steel is prepared by the following steps: after austenitizing treatment of the medium-low
alloy steel, high-temperature hot deformation treatment is performed, then the medium-low
alloy steel is cooled to a first preset temperature at a first
cooling speed, continuous warm deformation is performed between the first preset temperature and a second preset temperature, the medium-low
alloy steel is cooled to
room temperature, and then low-temperature
tempering treatment is performed. The high-
plasticity 3GPa-grade medium-low
alloy steel has excellent
work hardening capacity, solves the problem of low plasticity of the existing super-high-strength steel, enables the material to have excellent plasticity under the condition of super-high strength, and significantly reduces the total amount of expensive
metal elements such as Mo and Ni, reduces the material composition segregation of the material, and improves the service stability of the parts prepared from the material.