1、 Unit performance and main parameters

Rolling force: 13000kn

Rolling speed: 0-500-1200m / min

Bending force of work roll: (single side positive / negative); 350 / 210kN

Cooling medium: emulsion

Roller system lubrication: oil air lubrication

Q20895 and other low alloy steel plates.

Thickness of finished product: 0.10-0.35mm

2、 Bearing configuration of backup roll system:

Three, there are problems

The rolling body of the main bearing on the roll body of the operating side spalled off and cracked, and the cage pillar was broken. A row of outer rings on the locking nut side of the positioning bearing were damaged and cracked. Through on-site disassembly of the roller system and physical inspection of each matching part and the damaged bearing, the reason search process and analysis are as follows:

4. Damage forms of bearings and matching parts
1. The roller spalling and cracking occurred on the side of the rolling body, and the cage pillar was broken. The observation found that the spalling position of the rolling body was regular and consistent, that is, the position and morphology were consistent, as shown in the figure:

2. Metal friction interference occurs between the moving labyrinth ring and the mating surface of the bearing box.

3. The inner ring peels off and the wear track is unusually wide, far exceeding the total length of the rolling body (middle convex rolling body).

4. The outer ring of the locking nut side of the positioning bearing is damaged, and the double row cages are abnormally worn.

5, sealing ring lip wear, local fracture.

6. The contact area between the distance ring and the end face of the positioning bearing as well as the contact area with the end face of the inner ring of the main bearing is seriously worn.

5. Phenomenal analysis
1. Based on the above damage forms and the stress analysis of the assembly structure, it can be judged from the fourth point that abnormal axial load is generated from the transmission side operating side when the rolling mill is running, which leads to abnormal wear of the positioning bearing cage and damage and cracking of the outer ring on the lock nut side.

2. Because the positioning bearing limits the axial displacement of the roll, after the positioning bearing is damaged, the axial movement of the roll can not get the two-way limit, so the second fault is caused. The metal friction interference occurs between the moving labyrinth ring and the matching surface of the bearing box, and the screws fixing the sealing ring are worn seriously, leading to fracture. Then affect the sealing effect of the sealing ring.

3, the damage form point 3, inner ring wear track over rolling total length, can judge, exists when bearing is running around the bidirectional axial displacement, roll drive roller displacement, the lateral operation when the drive side displacement, axial force is big, cause the roller end wear crack, cause peeling, cracking, and extrusion die card, the deformation fracture cause cage.