The invention belongs to the technical field of materials, and relates to an ultra-high-strength heat-resistant gear bearing steel with ultra-hardened
surface layer and a preparation method thereof. The
chemical composition of the steel comprises the following chemical components of, in percentage by
mass, 0.08-0.18% of C, 10.0-16.0% of Co, 3.0-8.0% of Ni, 3.0-7.0% of Cr, 3.0-6.0% of Mo, 0.5-2.0%of W, 0.2-1.0% of V, 0-0.1% of Nb, and the balance Fe and
impurity elements. According to the method,
vacuum induction melting,
vacuum induction melting and
vacuum arc remelting or
vacuum induction melting and electroslag remelting are adopted for
smelting. Steel ingots are
diffusion annealed and forged into steel products. Steel samples are subjected to preliminary heat treatment, carburization and final heat treatment, the tensile strength of the steel is not less than 1900 MP a, the yield strength is not less than 1600 MP a, and the carburized surface
hardness is not less than 850 HV (equivalent to 66 HRC). The method has the advantages that compared with the prior art, the method has higher tensile strength, yield strength and relatively good
plasticity,
toughness and
heat resistance,has excellent surface carburization super-hardening performance and fatigue performance, and achieves good matching of the core super-
toughening and surface super-hardening.