Lubrication Methods and Maintenance of Rolling Mill Bearings

1. Lubrication Methods

The lubrication principles of rolling mill bearings are fundamentally similar to those of other rolling bearings. However, the harsh working conditions of rolling mill bearings significantly impact their performance, and effective lubrication plays a crucial role in determining their operational efficiency.

Rolling mill bearings primarily use grease lubrication and oil lubrication. Grease lubrication combines lubrication with sealing, providing a simple sealing structure and lubrication facility. Due to its convenience in replenishing grease, rolling mill bearings generally adopt grease lubrication when working conditions permit. Oil lubrication, on the other hand, offers strong cooling effects and helps remove contaminants and moisture from the bearings.

The lubrication methods for rolling mill bearings using oil include pressure oil lubrication, oil jet lubrication, oil mist lubrication, and oil-air lubrication. Pressure oil lubrication is the most effective lubrication method for rolling mill bearings under normal operating speeds. Oil jet lubrication involves spraying lubricating oil into the bearing under pressure, often used in high-speed rolling mill bearings or situations where pressure oil lubrication cannot meet cooling requirements. Oil mist lubrication entails spraying oil mist from dry compressed air into the bearing for lubrication, suitable for large rolling mill bearings with high rolling speeds and precision requirements, or for bearings that are not frequently disassembled from the bearing box. Both pressure oil lubrication and oil jet lubrication require the installation of oil inlet and outlet pipes, lubrication pumps, oil reservoirs, and sometimes an oil cooler, making them relatively expensive and less commonly used in rolling mill bearings.

2. Maintenance

During the use of bearings, regular maintenance and monitoring are essential to extend their service life.

Ensure lubrication oil passages are unobstructed, select the appropriate lubricant, and regularly add the required amount of lubricant. Maintain good oil film lubrication on the rolling surface and sliding surface between the rollers and the edge guide.

Regularly check the sealing condition of the seals and promptly replace damaged seals. Ensure the sealing performance of the bearings to prevent water and rust from entering the bearings and to prevent lubricant leakage.

Conduct active monitoring of the bearing's operating conditions based on the specific conditions of the enterprise.

Noise Monitoring: During normal operation, a smooth humming sound is expected. Regularly compare the sound with the normal condition to detect anomalies promptly.

Lubricant Monitoring: Normal lubricants should be clear and clean. Dirty lubricants may contain worn particles or contaminants.

Temperature Monitoring: Abnormalities in operation will result in temperature increases. Our company has implemented temperature monitoring and is willing to provide more extensive services to customers.

Establish record cards to document the bearing's online usage days, steel production volume, maintenance, and monitoring conditions. Strengthen the management of the bearing's operating conditions.

Storage and Preservation of Rolling Mill Bearings

Rolling mill bearings are precision mechanical components with strict requirements for storage and preservation.

Warehouse Temperature: Bearings are coated with rust preventive oil before leaving the factory. Both excessively low and high temperatures can cause the rust preventive oil to deteriorate. The warehouse temperature should be controlled between 0-25°C.

Warehouse Humidity: Excessive humidity can cause bearing rust. The relative humidity in the warehouse should be maintained between 45% and 60%.

Warehouse Environment: Ideally, bearings should be stored separately. If stored with other items, ensure they are not chemical substances such as acids, alkalis, or salts. Bearings should be stored above the ground and away from heating pipes.

Regular Inspection: According to the rust prevention requirements of bearing products, regular inspections should be conducted every 10-12 months. If rust is found on the oil seal packaging, resealing should be performed.