Whether the working performance of the rolling mill bearing can be effectively utilized depends to a large extent on the lubrication. The lubricant is called the “fifth largest component of the bearing”. More than 40% of the damage of the rolling mill bearing is caused by poor lubrication. Therefore, to reduce the bearing consumption of the rolling mill, it is necessary to select a lubrication method suitable for the conditions of use and a high-quality lubricant, and also to design and install a reliable anti-invasion of water and scale. Sealing means.

At present, the rolling mill bearings mainly use grease lubrication and oil and gas lubrication. Most of the manufacturers now use simple and easy grease lubrication. If it is possible to adopt oil and gas lubrication technology, the rolling mill bearings can work under ideal lubrication conditions, which will greatly reduce bearing consumption.

1, grease lubrication

The grease lubrication method has the characteristics of simple and easy operation, convenient roll replacement, and wide application. The appropriate grease should be selected according to the working temperature, rotation speed, rolling force, sealing waterproof performance, impact vibration size, and grease supply method of the rolling mill bearing. Greases of regular manufacturers with high temperature resistance, high viscosity, excellent extreme pressure performance and high water repellency resistance should be selected. According to the working characteristics of the rolling mill bearing, 2#, 3#, lithium base grease or polyurea containing EP additive should be selected.

Although the high-performance grease purchase cost is high, the amount of use is small, the bearing life is long, and the total integrated cost is reduced. In addition, the filling amount of the grease must be in an appropriate amount and filled in place. The grease of different grades cannot be mixed, so that the working surface of the bearing of the rolling mill is always in the normal state of the oil film.

2, the amount of fat

Fill the inner space of the bearing when filling the grease for the first time. For the vertical roller or the inclined roller, fill the upper and lower covers of each bearing seat with a sufficient amount of grease. After each roll change, check whether the grease is hardened and blackened, contaminated with impurities, and oxidized and emulsified. If the above situation occurs, the grease should be completely replaced and the seal and sealing structure should be replaced or improved in time; if the situation is still good, the new grease can be added and continue to be used.

3, oil and gas lubrication

Oil and gas lubrication is the ideal lubrication method for bearings. During the working period, the compressed air enters the bearing with lubricating oil at intervals. The lubricating oil stays inside the bearing, and the air takes away the heat in the bearing operation while preventing external impurities. Water vapor invades the inside of the bearing. The oil is not atomized and does not pollute the environment.

4, sealing device

The seal of the bearing is to maintain a good internal lubrication state, and prevent the cooling water, iron oxide scale and impurities from immersing into the working surface to prolong the service life of the bearing. Due to the bearing seal problem of the rolling mill, the most damage to the bearing is the part near the side of the roller. The bearing is often contaminated and lost due to grease, causing the working surface of the part to wear, peel off or even chip, especially the infiltration of the emulsion of the cold strip mill. Grease failure is faster.

Bearing seals are divided into self-contained seals and external seals. The outer seal is mainly designed with a combination of labyrinth and contact. The more stages of the labyrinth (not less than the two poles), the smaller the gap, the better the sealing effect. The gap of the labyrinth is 0.6 to 1.5 mm on one side and 4 to 6 mm in the axial direction according to the size of the bearing.

Contact skeleton oil seal: It is widely used in rolling mills, and can be used side by side in order to increase the effect. The oil seal is directional and cannot be reversed. The hot rolling mill is usually equipped with two oil seals, and the two oil seal lips must be directed outside the bearing housing to prevent external dirt from entering. The cold strip mill is generally equipped with three oil seals. The oil seal lip close to the bearing is to be inward to prevent the grease from overflowing and affecting the quality of the rolled material. Be careful when using the oil seal to avoid damaging the lip when loading the roller and affecting the sealing effect.

RBR type seal ring: This is a rubber lip seal ring for rolling mill bearings, which has been widely used in recent years. The RBR sealing ring adopts the axial sealing method, and the lip is attached to the base surface of the gland, which is not affected by the roll beating. The old grease inside the bearing can overflow, and the external cooling water, iron oxide scale and impurities are blocked by the lip. Enter, have a good sealing effect. Moreover, it is convenient to use, and the roll is loaded into the bearing seat without any influence when the roll is changed.