Four row cylindrical roller bearings are widely used in metal rolling, rubber vulcanization, thermoplastic calendering and other industries. According to different industries and different use environment, there are personalized requirements for the raw materials, internal structure design and bearing manufacturing accuracy of bearing manufacturing. The dimension and inner ring of the four row cylindrical roller bearing have reached the standard design in the rolling mill bearing manufacturing industry. Of course, there are also users with special requirements. Especially in metallurgical hot rolling narrow strip, bar wire and other small size section steel, due to the different process and working conditions, the bearing inner sleeve will appear the following several common failure forms.