The input gears of the rolling mill gearbox belong to the high-speed end and have high requirements for bearings. This steel enterprise uses imported bearings for its rolling mill gearbox. Bearing cages of the bearings would break down every three months or so, requiring the shutdown for bearing replacement, which has reduced production efficiency. A well-known domestic gearbox manufacturer intends to use Wazhu bearings for its equipment. Therefore, they invited Wazhu engineering technicians to deeply explore the operation conditions of the equipment in the steel enterprise, inspect the phenomenon of broken bearing cages of imported conical bearings on-site, and conduct failure analysis. Wazhu adjusted the bearing selection and related parameters based on the simulation calculation results and optimized the design of the supporting bearings. They successfully overcame this problem. Currently, the customer has ordered 10 sets of gearbox bearings for the rolling mill.