The reasons why the bearings of steel mill rolling machines are prone to damage and the solutions for addressing the problem
High load and complex conditions
Extreme load shock
The rolling mill bearings have to withstand 2 to 5 times the radial load of ordinary bearings. Moreover, they are affected by various working 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 cause additional axial sliding friction force, leading to single-load damage of the four-row tapered roller bearings (such as the common burnout of the fixed end bearings on the operating side).
Lubrication system problem
Sliding friction failure
Sealing aging and emulsified liquid intrusion lead to the dilution or loss of the lubricating grease, resulting in the rupture of the oil film and the formation of dry friction, which causes high-temperature burning damage.
*Data: Poor lubrication can reduce the lifespan of bearings by 30% to 50%.
2. Insufficient quality of lubricant
Using low-quality lubricating grease or failing to replace it regularly leads to a decline in lubrication performance, accelerating wear and fatigue shedding.
Assembly and maintenance defects
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
Sealing failure
The sealing of the labyrinth or the aging of the rubber has caused 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, impurities (such as residual particles remaining in the oil passage after not being cleaned) are introduced, which aggravates the wear of the contact surfaces.
Materials and Design Constraints
Material defect
Improper heat treatment of bearing steel leads to insufficient hardness or loose structure, which accelerates fatigue spalling.
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