Description: This paper mainly describes the answers to possible problems in steel rolling
Keyword: Rolling roll, rolling force, rolling, steel rolling
1. How to control the rolling force?
The rolling force is large and the shape is not easy to control, the temperature of the roll is uneven, and the bearing capacity of the roll is reduced. New work rolls generally use large tension to reduce the rolling force, which can be reduced after rolling 2-3 rolls.
Relatively speaking, the rolling force is too small and the thickness is difficult to control. The resistance of the tension roll can be reduced and the rolling force can be relatively larger.
2. How to control thickness fluctuation?
Large thickness fluctuations occur during the rolling process. First, reduce the speed and reduce the tension difference. If the thickness fluctuations are large, the monitoring can be cancelled.
For thickness fluctuations within 20 μm, the speed should be below 500 meters, and for fluctuations above 20 μm, the speed should be below 300 meters.
3. How is the cracked edge caused?
1. Low roughness of the roll edge.
2. Chromatic aberration appears at the edge of the strip.
3. The total deformation is too high, and the reduction in the final pass is too large, which may cause edge cracks after rolling.
4. The raw material has edge waves, swelling and cracking.
5. Poor pickling and trimming.
4. How to control cracked edges and broken belts?
When the edge crack is serious, reduce the bending force of the work roll, reduce the rolling speed, and reduce the exit tension. The tension on the edge of the strip is reduced, and the cracked edge will not be broken. It is found that the edge of the strip is bulging and the work roll is replaced in time.
5. In the rolling process, what is the reason for the deviation of the belt line and the wrong coil? How to deal with it?
In the rolling process, the deviation of the strip generally occurs during belt threading or tail flicking. The main reasons for the deviation of the strip are as follows:
1. Due to the incoming material, the shape of the incoming material is not good, there are serious edge waves or wrong edges, so that the centering device of the uncoiler cannot be adjusted accurately and in time, causing the strip to deviate in the first pass. The measures to be taken are: The rolling speed should not be too high, adjust the reduction side position in time or stop in time.
2. Reasons for operation The unreasonable adjustment of the swing due to the operation depresses the strip, which causes the strip to run out of direction.
3. Electrical reasons Due to the sudden decrease or disappearance of the tension of the coiler during the rolling process, the strip is deflected and the strip is broken.
4. Due to the serious taper of the roll after the roll is ground, the reduction is inaccurate, which increases the difficulty of the operation and swing during the rolling. The lighter one will produce severe side waves and cause plate shape defects, and the heavy one will cause deviation. Broken tape.
5. Malfunction of the unwinding centering device, pollution of the lamp tube or receiving device, etc., causing the deflection device to fail and cause the first deflection.
6. How to control the head and tail rollers by the main control worker, front and rear of the machine?
1. When rolling the lead and tail, the main controller should increase the exit tension by about 5KN in time. When the rolling force is reduced after starting the car, the exit tension should be adjusted to the amount required by the process. Due to the low speed of the belt head and belt tail, the rolling force is large, the thickness is not well controlled, and the bending roll cannot keep up with the easy roller.
2. Before and after the machine, observe the rolling force and plate shape in time. When the rolling force is large, increase the bending roll in time. Observe the plate shape and adjust the gap of the roll in time to avoid deviation from the roll.
7. What are the precautions for roll reeling when there is no bias?
In general, when there is no deflection, the precautions are: whether the deformation of the pass is too large, whether the rolling force is too large, whether the bending force is too small, and whether there is any loss of tension when starting the car.
8. What should I do if there is a sudden chromatic aberration on the surface of the strip during the rolling process?
During the rolling process, the main control worker observes the front and rear display screens at any time. If it is found that there is a sudden color difference on the surface of the strip during rolling, the speed should be reduced to 100-200 meters in time, and the front and back of the machine should be notified to observe whether there is any abnormality on the surface of the strip. If the problem is found, stop and solve it in time.
9. What equipment and solutions should be checked for the chromatic aberration of the entire roll on the surface of the steel strip?
1. First, check whether there are small pits on the surface of the strip with chromatic aberrations. If there are pits, it is likely that the chromatic aberration is caused by the low hardness of the work roll. Solution Replace the work roll
2. Check the middle roller and support roller for bruises and meat loss. Replace the intermediate roller, support roller or sanding.
3. Check whether the emulsion nozzle is blocked. Clean the nozzle.
4. Check whether the horizontal position of the middle roller is in the correct position. Move horizontally to the correct position.
5. Check whether the pickling raw materials have color difference in the same position. The response is given to the pickling quality staff and adjusted in time.