Iii. Reason analysis

It can be understood from the bearing characteristic that the cylindrical bearing rolling body is in straight contact with the inner and outer ring, and all the rolling body in the stress zone are in contact with the raceway of the inner and outer ring at the same time under normal stress.

From the current damage characteristics: most of the bearing inner sleeve damage is by the roll side, from the above picture to see that the bearing inner ring has obvious force offset load.

5. Suggestions on countermeasures

It is analyzed that the bearing damage is mainly caused by heavy rolling load and radial off-load, which leads to serious local wear of inner sleeve. Cause fatigue damage, in the appearance of corrosion spots if not timely off the machine or replacement, it will expand along the direction of circulation, more and more large, resulting in bearing failure.

At the same time, it is judged that the main causes of off-load are the increase of rolling force, the increase of force deformation or spring of rolling mill and the inclined cross of roll system, which lead to the existence of off-load in the running of bearing.

Short stress rolling mill:

1. Check whether the oval and taper of the bearing box are out of tolerance.

2. Maintain the accuracy of rolling mill, reduce the deformation and bounce of rolling mill, such as replacing the copper sleeve of column and restoring the matching gap between bearing seat and column.

3, control roll diameter precision, especially taper control.

Arch mill: the roll system appears cross or tilt, such as: rolling mill down device failure, resulting in large roll gap difference; The large size difference between the arc-shaped backing plate at the bottom of the bearing seat on the drive side and the operating side of the lower roller box leads to the dislocation of the center line of the bearing on the drive side and the operating side; Bearing seat and arch clearance wear greater, rolling shear difference and so on, will lead to bearing force asymmetry.

According to the damage position and frequency of the site are mostly 2 frames, it is judged that the main factors causing the site bearing damage are: abnormal contact position between 2 frames and bearing seat,

It can be targeted to measure the gap between the bearing seat and the arch, especially whether the gap is consistent on the measuring and operating side of the same shaft transmission, and whether the gap meets the required gap, so as to avoid that the gap between the roller system and the arch is too large and the couple moment is generated, so that the bearing is off-load. The fit clearance between the bearing box and the frame plate should be reduced as far as possible (restore the initial required clearance) to mitigate the impact on the bearing when the transmission is not smooth or over steel, as well as the roll inclination during rolling.

At the same time, it is important to strictly control the size H of the center distance from the bottom arc pad of the bearing box (transmission side and operation measurement) on the same roll. Mutual difference is recommended < 0.3mm. The support roller system is assembled and installed to the frame to maintain the level (drive side and operation measurement).

At the same time, bearing: strict control of bearing clearance, accuracy and reasonable transportation, actively listen to field suggestions, cooperate with adjustment.