Analysis of the problems and providing solutions to rolling mill bearings

Jan 12, 2024

Rolling mill bearings play a very important role in rolling mill equipment, mainly reflected in the following aspects:

Support and positioning: The main role of the roll neck bearing is to support the roll and ensure its correct position in the frame. During the rolling process, the rolls must bear huge loads, including rolling force, the rotational torque of the rotating rolls, etc. Therefore, the bearings need to be strong enough to resist these forces to maintain the stability and accuracy of the roll.

Reduce the friction coefficient: The friction coefficient of the bearing has a great impact on rolling energy consumption. The greater the friction coefficient, the higher the energy consumption of the rolling mill. Therefore, bearings need a smaller friction coefficient to reduce energy consumption.

Ensure product accuracy: The stiffness of the bearing has a certain impact on the dimensional accuracy of rolled products. If the bearing stiffness is insufficient, it will cause product size fluctuations and affect product quality. Therefore, the bearing must have a certain stiffness to ensure the product's dimensional stability.

Improve operation rate: The service life of bearings is directly related to the operation rate of the rolling mill. If the bearings are frequently damaged, it will cause frequent shutdowns of the rolling mill, seriously affecting the operating rate. Therefore, choosing high-quality, long-life bearings is an important means to improve the operating rate of rolling mills.

Ease of maintenance: The structural design of the bearing also needs to consider its maintainability. Modern rolling mill bearings are used in rolling mill stands to ensure quick change and save time.

Environmental protection function: During the use of the rolling mill, bearings also need to consider environmental protection and safety issues. For example, the selection and use of lubricants need to comply with environmental standards and ensure that the bearings do not generate excessive temperatures or noise during use to protect the safety and health of operators.

To sum up, rolling mill bearings play an important role in rolling mill equipment, and their quality and service life directly affect the rolling mill's performance, product quality, and operating rate. Therefore, correctly selecting and maintaining rolling mill bearings is crucial to operating rolling mill equipment.

TDIK Tapered roller bearings HM959740DW – 902A1 problem

However, steel mill customers will still face various bearing problems during use. Today, we will explain the case of tapered roller taper pin grinding.

The customer sends the email below:

We are facing a wear and tear issue in the pins of the Backup Roll's Thrust bearing; these pins are installed on the cups of bearings (ppt attached). Needs your expert opinion on the causes of the said issue.

After receiving the question from our customer, our engineers discussed the questions, and they think: 

Under normal working conditions, the CUP of the thrust tapered roller bearing does not rotate. The photo shows that the end face of the CUP and the CHOCK-COVER have ring-shaped wear. These scratches are mainly caused by spring damage. Some spring remnants are sandwiched between CUP and COVER. But this is not the main reason for bearing damage. 

We need to know whether this CUP has a positioning key. The positioning key is not in the CUP but is in INNER-RACE.

Our engineers think the most likely cause of wear is no positioning key on the cup.

Under normal working conditions, the CUP of the thrust tapered roller bearing does not rotate. But the cup of your bearing rotates, which will wear the spring and cause the spring to peel off. Spring fragments are sandwiched between CUP and COVER, causing wear when rotating. Generally, the hardness of CHOCK is lower than the hardness of the bearing, and the peeled iron slag will damage the bearing box and cover.

Currently, we have the following two solutions:

1. Customize new bearings with positioning key.

The cup design of our customized new bearing has a positioning key. After installation, the key on the cup and the key on the chock should be in the same position, and then the positioning pin is inserted. In this way, it can ensure the cup does not rotate in the chock, so there will be no problems with the spring or wear problems.

It is one of our advantages because our FV bearings can be customized for customers in small quantities according to their actual working conditions to a greater extent. We have customized solutions and bearings for customers in many steel mills and have received good feedback.

2. We can repair the original bearings, a service we often provide for large domestic steel mills. It can retain more of the original bearing materials and characteristics, but the problem is that this model alone may not be cost-effective. 

We FV analyze the reason and provide solutions for customers according to the customer's specific situation. Welcome to contact me if you have any requirements or technical problems.