In the metallurgical industry, rolling mill bearings work in heavy load, high impact load, high temperature, water vapor and dusty environment, and the working conditions are very bad. The mill line uses four rows of cylindrical roller bearings to support radial loads, thrust rollers or thrust ball bearings, and radial angular contact balls or radial roller bearings to support axial loads. Four-row cylindrical roller bearings are mainly used as main roller bearings in metallurgical equipment. Because of its compact structure, good rigidity and high bearing capacity, it is a widely used rolling mill bearing. Because the inner ring has no flange, it cannot bear axial load.