Measures to Prolong Roll Bearing Life

Aug 22, 2023

A high-quality bearing is a must for rolling mill rolls. Usually, the bearings used in rolling mills include four-row cylindrical roller bearings, two-row cylindrical roller bearings, four-row tapered roller bearings, spherical roller bearings, angular contact ball bearings, deep groove ball bearings, thrust bearings, etc. Proper maintenance during use is an important way to improve the service life of roll bearings. Today we will introduce several measures to extend the life of roll bearings.

First of all, establish the use files for the bearings and clean and check the bearings regularly. Use gasoline or kerosene when cleaning, and use it after drying completely; check the wear of the inner and outer ring working surfaces and rolling element surfaces; and rotate the outer ring of the bearing by 120°–180° every 600–800 hours of operation to change its stress position, which can prolong its service life.

Secondly, adjust the clearance of the bearing when disassembling the bearing seat. The assembly accuracy that has the greatest effect on the life of roll bearings is the clearance. The size of the clearance directly determines the load distribution state inside the bearing, especially the change in the maximum rolling element load in the bearing. If the clearance is too large or too small, it will cause roll shifting, bearing burning, and locking during rolling. The internal clearance of the bearing often changes due to the influence of fit, operating temperature, deformation after loading, etc. Therefore, readjusting the clearance reasonably when disassembling the bearing seat can significantly improve the bearing's service life.

Thirdly, choose the lubrication method reasonably. The purpose of bearing lubrication is to form an oil film on the rolling surface, and an elastic hydrodynamic lubricating oil film is formed between the metal surfaces to reduce the wear of the metal surface and increase its service life. According to the speed and load conditions, the roll bearings can be lubricated by thin oil lubrication, dry oil lubrication, oil mist lubrication, or oil-air lubrication. When using dry oil lubrication, due to the washing of the rolling oil, the dry grease is dissolved into the rolling oil, polluting it and then causing oil spots on the surface of the steel, which affects the product quality, so it is rarely used. In addition, due to the disadvantages of complex working conditions in thin oil lubrication and environmental pollution in oil mist lubrication, oil-air lubrication is widely used in the lubrication of roll bearings in modern steel rolling mills. Oil-air lubrication has the advantages of high lubrication efficiency, environmental protection, a wide viscosity of usable oil products, low operation and maintenance costs, low fuel consumption, and good monitorability. It is especially suitable for high-speed rolling mills, such as wire rod mills.

The picture above shows lubricating grease.

Finally, a reasonable choice of sealing method is also essential. As long as the seals and sealing methods are selected well, the consumption of the roll bearings is generally less. On the contrary, the consumption of the bearing must be high. While choosing a reasonable sealing method and reliable quality seals, there has been a development trend of using sealed bearings in domestic and foreign plate and strip mills; that is, at both ends of the bearing and the inner isolation ring, etc., seals are used to seal the bearing again. Although this sealed bearing occupies a certain design space in use, due to the good sealing, the bearing is always in a fully lubricated state and a clean working environment, which significantly improves the service life of the bearing.

Through the above steps, the actual service life of the roll bearing will be more consistent with the estimated service life, which will greatly reduce the cost of the iron and steel enterprises. FV Metallurgical Bearings is a professional manufacturer of rolling mill bearings, escorting your rolling bearings.

The picture above is of the four-row cylindrical roller bearing 314553 C4 manufactured by FV Bearing for the customer of the iron and steel plant. It is used on the work roll of the rolling mill and is usually used in conjunction with deep groove ball bearings or angular contact ball bearings.