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Use and maintenance knowledge of rolling mill bearings

Use and maintenance knowledge of rolling mill bearings


Roll bearings are used to support rolls. Compared with general-purpose bearings, roll bearings have the following characteristics:

Withstand high unit pressure 01

Because the outer dimension of the bearing seat is restricted, it cannot be larger than the minimum diameter of the roll body, and the length of the roll neck is short, so the unit load on the bearing is large. The unit pressure of general roll bearings can be as high as 2000-4800Mpa, which is 2-5 times that of general bearings, and the PV value (the product of unit pressure and linear velocity) is 3-20 times that of general bearings.

Big difference in operating speed 02

Different rolling mills have different operating speed requirements, and the speed difference is still very large. For example, the export speed of the modern six-stand cold casting and the continuous rolling mill has reached 42m/s, and the export speed of the high-speed wire rod mill has reached 100m/s. The speed of the low-speed rolling mill is only 0.2m/s. Obviously, different types of bearings should be used for rolling mills of different speeds.

Bad working conditions 03

During hot rolling, the rolls must be cooled by water, and some dirty water, iron oxide scraps, etc. are likely to be immersed in the bearing. The cold rolling mill selects a process smoothing agent (emulsion, etc.) to smooth the material of the cooling roll and the rolled piece, and the smoothing agent cannot be mixed with the bearing emulsified liquid. This puts forward higher requirements on the sealing of the bearing.


Therefore, the requirements for roll bearings are large load-bearing capacity, small impact coefficient, impact resistance, and work at different speeds; in terms of structure, the radial dimension should be as small as possible (in order to select a larger roll neck diameter ), with excellent smoothing and cooling conditions. When necessary, the roll bearings need to be removed from the rolling mill for testing and maintenance, so as to maximize the service life of the roll bearings. The frequency of bearing maintenance and maintenance should be adjusted according to the working conditions of the rolling mill, mainly according to the operating conditions. The general maintenance frequency is that full-load bearing work is inspected every three months, most rolling mills are maintained every six months, and light-load working rolling mills are maintained every twelve months.

Roll bearings should be inspected separately after the initial work for 1000h. During the maintenance process, the bearings must be cleaned completely, and the oil seal should be checked at the same time. If it fails, the oil seal should be replaced completely. If no abnormality is found, the second check time can be extended, for example, after every 2000h or more, from the rolling mill Remove the bearing and bearing seat and other components, check the working condition, and record the bearing position and bearing area of the rolling mill each time.

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