Common Issues and Solutions in Steel Rolling Operations

1. Rolling Force Control
Excessive rolling force complicates shape control and causes uneven roll temperatures, reducing bearing capacity. New work rolls typically employ higher tension to decrease rolling force, with noticeable reduction after 2-3 rolling cycles.

Insufficient rolling force hampers thickness control. Reducing tension roll resistance can relatively increase rolling force.

2. Thickness Fluctuation Management
For significant thickness variations during rolling:

• Reduce speed and minimize tension differences

• Cancel monitoring for major fluctuations

• Maintain speeds below 500 m/min for variations under 20μm

• Limit to 300 m/min for variations exceeding 20μm

3. Edge Crack Causes

1. Insufficient roll edge roughness

2. Strip edge discoloration

3. Excessive total deformation or final pass reduction

4. Raw material defects: edge waves, bulging, cracking

5. Inadequate pickling or trimming

4. Edge Crack and Breakage Control
For severe edge cracks:

• Reduce work roll bending force

• Decrease rolling speed

• Lower exit tension

• Replace work rolls immediately upon detecting strip edge bulging

5. Strip Deviation and Miscoiling
Primary causes and solutions:

1. Poor incoming material shape: Reduce speed, adjust reduction position, or stop

2. Operational errors: Correct improper swing adjustments

3. Electrical issues: Address tension drops at coiler

4. Roll taper problems: Regrind severely tapered rolls

5. Equipment malfunctions: Maintain centering devices and sensors

6. Head/Tail Control Procedures

1. Increase exit tension by ~5KN during head/tail rolling

2. Adjust tension to process requirements after rolling force stabilizes

3. Monitor rolling force and shape closely

4. Adjust bending force and roll gap promptly

7. Non-Deflection Rolling Precautions

• Verify pass deformation amount

• Check rolling force magnitude

• Ensure adequate bending force

• Confirm tension maintenance during startup

8. Sudden Surface Discoloration Response

• Immediately reduce speed to 100-200 m/min

• Notify operators to inspect strip surface

• Stop and resolve if abnormalities are confirmed

9. Full-Roll Discoloration Analysis

1. Inspect for surface pitting → Replace work rolls if hardness insufficient

2. Check intermediate/backup rolls for damage → Replace or regrind

3. Verify emulsion nozzle blockage → Clean nozzles

4. Confirm intermediate roll horizontal position → Adjust to correct position

5. Check pickling raw materials → Notify quality personnel for adjustment