High load and complex conditions

1.Extreme load impact

The rolling mill bearings need to withstand 2 to 5 times the radial load of ordinary bearings. Moreover, they are affected by various conditions such as sudden changes in rolling force, strip breakage, and deviation, which can cause local fatigue cracks or fractures in the rolling elements. *Case: The outer ring raceway of the supporting roller bearing of the hot rolling machine peeled off or the rolling elements broke due to overload. *

2. Axial force imbalance 

If the axis of the rolling mill rolls is not parallel or if the form and position tolerance deviation of the frame exists, it will lead to additional axial sliding friction force, causing single-row overload damage to the four-row tapered roller bearings (such as the common burnout of the fixed end bearings on the operating side).

Lubrication system problem 

1. Lubrication failure

Sealing aging and emulsified liquid intrusion lead to dilution or loss of the lubricating grease, resulting in the rupture of the oil film and dry friction, which causes high-temperature burnout.

*Data: Poor lubrication can shorten the service life of bearings by 30% to 50%. 

2. Insufficient lubricant quality

Using low-quality lubricating grease or failing to replace it regularly leads to a decline in lubrication performance, accelerating wear and fatigue flaking. 

Assembly and maintenance defects 

Assembly and maintenance defects 

1. Insufficient installation accuracy 

The coaxiality of the bearing housing is poor, and the interference fit between the roller neck and the inner ring is inappropriate (for example, if the interference exceeds 0.1mm, it can cause the 

inner ring to crack, or if the interference is insufficient, it can lead to creeping wear). 

*Example: When the surface unevenness of the roller neck exceeds 0.1mm, the risk of the inner ring of the bearing cracking significantly increases. *

2. Inappropriate adjustment of clearance 

If the clearance of the four-row tapered roller bearings is too large or too small, it will cause local stress concentration or abnormal temperature rise.

Foreign matter intrusion and contamination

1. Seal failure 

The sealing of the labyrinth or the aging of the rubber causes iron oxide chips, water and dust to enter the interior of the bearing, leading to abrasive wear and corrosion. 

*Impact: When the foreign object is larger than the bearing clearance, it will directly crush the rolling element or embed itself in the raceway. *

2. Insufficient cleaning 

During assembly or maintenance, if impurities (such as residual particles remaining in the oil passage after cleaning) are brought in, it will accelerate the wear of the contact surfaces.

Material and Design Constraints

1. Material defect 

Improper heat treatment of bearing steel leads to insufficient hardness or loose structure, which accelerates fatigue spalling. 

2. Poor structural adaptability 

Non-customized bearings are unable to meet the dynamic adjustment requirements of the rolling mill roll system (such as roll displacement and roll bending actions), resulting in uneven stress distribution. 

The use of custom bearings in the rolling mill's rolling machines is a key measure to address high loads, complex working conditions and precision requirements.

The necessity of custom-made bearings

1. Matching special working conditions

The rolling mill needs to withstand extremely high radial loads (up to 2-5 times that of ordinary bearings) and frequent roller replacement impacts, and is also exposed to harsh environments such as the intrusion of lubricating fluid and iron filings. Customized bearings can enhance durability by optimizing materials (such as high-temperature bearing steel and stainless steel) and sealing designs. 

2. Adapt to the roller system structure 

For complex machines such as the six-roll HC rolling mill, the control of plate shape is achieved through the movement of the intermediate rolls and the bending of the working rolls. Customized bearings need to be compatible with both the axial guiding accuracy and the dynamic adjustment requirements.

The core advantages of custom bearings    

1. Performance enhancement 

- Bearing capacity: Four-row cylindrical roller bearings (such as the FCDP series) are specifically designed for high radial loads. When combined with thrust bearings, they can balance axial forces. 

- Speed adaptability: The asymmetric self-aligning roller bearing optimizes its internal structure to reduce operating temperature, enabling high-speed rolling. 

2. Dimension Optimization 

By customizing the inner ring cone hole design (such as the 313403C model), it is possible to match the roller neck size limitations and reduce installation errors.

Customization process

Requirement Analysis  

Specify the type of rolling machine (cold rolling / hot rolling), the load distribution (radial / axial), and the lubrication method (gas-oil / grease), etc.

Application Cases and Precautions

1. Typical configuration 

- Cold rolling machine: Typically uses a combination of four-row cylindrical roller bearings and angular contact ball bearings, which ensures both high rotational speed and axial positioning accuracy. 

- Hot rolling machine: Preferentially use four-row tapered roller bearings, which integrate radial and axial load-bearing capabilities and simplify the structural design. 

2. Maintenance Points 

Lubrication management: Utilize oil-gas lubrication to reduce frictional temperature rise and prevent early failure caused by the depletion of lubricating oil. 

- Installation accuracy: Use hydraulic tools to ensure that the bearing and the roller neck fit tightly, preventing crawling and wear.