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YUAN HUI
YUAN HUI
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Common Faults and Handling Methods of Rolling Mill Roll Replacement System

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The automatic roll change of the finishing mill is divided into four stages:

1. Preparation stage before changing rolls

2. Equipment downtime before roll change

3. Roll changing stage

4. Equipment recovery stage after roll change

  • Roll change process in preparation stage before roll change:

1. The roll changing trolley pushes the new roll from the initial position E1 (roller room) to the roll changing translation cover (E7) in front of the finishing mill (the translation cover is located on the side of the flying shear);

2. The roll changing trolley moves back to position E6, and the translation cover moves to the side of the coiler;

3. The roller changing trolley advances to position E11;

  • Equipment downtime before roll change

Shutdown process before roll change (switch to roll change mode):

1. The rolling mill has thrown steel;

2. The cooling water of the rolling mill is all closed;

3. The CVC of the rolling mill moves to the roll changing position;

4. The AGC of the rolling mill is in the unloading position;

5. The positioning of the shaft head has been completed;

6. The main drive stops;

7. The work roll balance (WR)) is switched to the constant pressure state;

  • Roll change and roll extraction stage·

1. The looper rises;

2. Pull out the entrance and exit guide;

3. Pull out the roller wiper at the entrance and exit.

4. The step pad moves to the roller changing position;.

5. WR is reduced to the minimum pressure;

6. The lifting track is lifted;

7. The roller changing trolley moves from E11 to E13, and the hook drops;

8. Close the lower shaft head support;

9. The lower WR locking baffle is opened;

10. The roller changing trolley moves from E13 to E12 position;- 11. The upper working roller descends;

12. Close the upper shaft head support;

13. The upper WR locking baffle is opened;

14. The roll changing trolley pulls the work roll out of the frame E7

  • Rolling mill Rolls changing stage

1. The traverse cover moves laterally to the side of the flying shear;

2. The roller changing trolley pushes the new roller from E6 to the position of E12; (note: the lifting track is in the rising position, the support roller and bending energy are in the roller changing position, and the locking baffle is opened)

3. Close the locking baffle;

4. Open the upper shaft head support;

5. Open the upper WR to the minimum pressure;

6. The roller changing trolley is pushed from E12 to E13 position;

7. Close the lower locking baffle;

8. Open the lower shaft head support;

9. Lower the work roll change track;

8. Turn on the work roll to balance to constant pressure;

9. Enter the value of the new roll;

10. Calculate the required gear of the new step mat and adjust the step mat;

11. Pull back the roller rubbing device at the entrance and exit, and pull back the guide guard at the entrance and exit;

12. The height adjustment of the guide plate on the entrance side;

13. Loop drop;

14. The cooling water is turned on;

15. Switch back to rolling mode;

Encountered failures and solutions

Fault 1. The cable reel motor tripped during the movement of the roller changing trolley.

In most cases, the problem is manifested as overcurrent of the cable drum motor, and thermal relay protection breaking in the MCC control cabinet.

Solution: After point inspection or electrical maintenance personnel reset the thermal relay in the MCC cabinet, notify the operator to reset the fault on the HMI screen

Fault 2: The translation cover of the roller changer does not move in place or cannot move.

There are two main reasons for this failure:

1) The translation cover does not move or only moves for a short distance; 2) The translation cover has been translated in place (see whether it is aligned on site), but the operation screen is not displayed in place;

Solution:

1) Check whether there is jamming on the translation cover, and solve it by manually poking the valve. The traversing system of the translation cover plate is controlled by a proportional valve. Before poking the valve, you should contact the operator to confirm that the on-site personnel are in a safe position, and you can just poke lightly;

2) If it is indeed in place on site, contact Ershi Metallurgy’s electrical personnel to check whether the position of the proximity switch and the detection signal are normal, and replace it if it is abnormal;

Fault 3:CVC roll shifting is not in place

1. The automatic sequence of roll change mode CVC roll shifting is not in place: after confirming that the work roll is in a balanced state, the mode can be switched again and the automatic sequence can be re-executed;

2. There are no rolls in the rolling mill for a long time (when repairing and recovering), and the position of a certain CVC hydraulic cylinder is incorrect: when the CVC roll shifting is in manual or automatic mode, the forced position is set to 0 Action hydraulic cylinder: Nx-RS_WR_REF (G2)

3. If the positions on both sides of the entrance and exit are consistent and the position value is within 1mm, the sealing operation can be considered

Fault 4: AGC cannot reach the unloading position

According to the fault alarm, the inspection personnel confirm on the spot:

1. Whether the actual position of the AGC cylinder is at the unloading position;

2. Whether the proximity switch detection is normal;

3. Whether the solenoid valve of the hydraulic system controlling the AGC is energized correctly;

4. Is there any foreign matter stuck on the AGC cylinder?

Fault 5: The axis positioning signal is lost

The shaft positioning signal sent by the transmission is lost, and the temporary program can be closed:

N3_RC-IN_SOFTWA_I ( G3 ) \LQD552.OR changed from 16#0000 to 16#0200

After the roller change is completed, the sealing point will be released.

Fault 6: The work roll balance action is not in place

1. Check whether the signal output of the solenoid valve is normal

If the signal is normal, but the shut-off valve does not move, the valve can be stabbed temporarily to ensure the balance system moves. Then check the solenoid valve head and electromagnet

2. Check whether the proportional valve has output

Fault 7. The looper is not in place

1. Confirm the actual position of the looper on site: when the actual position is reached, but the HMI display is not in place, the angle of the code disc of the looper can be temporarily adjusted or the operator can re-calibrate and then move the looper.

2. Confirm that the rolling mill exit guide and roller wiper are in position to prevent mechanical jamming.

Fault 7 The entrance and exit guides and roller wipers are not in place

1. Check the actual position of the guide and guard on site and the signal of the proximity switch

2. Check the actual position of the roller rubbing device and the pressure value displayed by the pressure switch

3. If necessary, the valve action equipment can be poked first to ensure that the roller is changed

Fault 8  lifting track

Before pushing the roller, confirm whether it is in place.

Check that there is no action on site, and confirm whether the signal of the proximity switch is normal and whether the signal of the solenoid valve on the valve table on the machine is correct. If the signal of the proximity switch is normal and the solenoid valve is energized, you can manually poke the valve to change the roller first, and then check the valve head and electromagnet. If you can’t manually poke the solenoid valve, replace the solenoid valve;

Fault 10. The shaft head is not hugged tightly during the roll changing process.

There may be two reasons:

1) Check the scene to see if it has been hugged and the proximity switch has been turned on;

2) If there is no action on site, check whether the signal of the solenoid valve on the valve table on the machine is correct. If the solenoid valve has been powered on, you can manually poke the valve and change the roller first, and then check the valve head and electromagnet. The solenoid valve must be replaced if it cannot be moved manually;

Fault 11 The work roll locking baffle cannot be opened/closed

1) Check the site to see if there is any jamming phenomenon; whether the position of the roller changing trolley is in place

2) Check whether the signal of the solenoid valve on the valve table on the machine is correct. If the solenoid valve has been powered on, you can manually poke the valve and change the roller first, and then check the valve head and electromagnet after being confirmed by someone on site. If it cannot be moved manually, the solenoid valve must be replaced;

3) Whether the connection part of the hydraulic cylinder is disengaged

Fault 12 The automatic timing ladder pad cannot be adjusted in place

After automatic sequence stop

1. Confirm that the roll data is correct

2. Confirm whether the balance pressure of the backup roller is 130Bar. If the backup roll is not in a balanced state, the operator needs to make adjustments: switch the control mode back to the rolling mode, switch the backup roll balance to Off mode, and then switch back to the Auto mode to check and confirm the balance pressure of the backup roll. (Multiple mode switching operations may be required)

3. After confirming that the status is normal, notify the operator to switch back to the roll changing mode and perform manual adjustment of the step pad.

Generally it is 5-10 days if the goods are in stock. or it is 15-20 days if the goods are not in stock, it is according to quantity.

A: Payment<=1000USD, 100% in advance. Payment>=1000USD, 30% T/T in advance ,balance before shippment.

Always a pre-production sample before mass production;
Always final Inspection before shipment;
During the epidemic, provide remote detection technical support

Tell us a little about your application and we’ll get back to you to finalize a quotation to meet your needs as quickly as possible.

Rolling mill rolls product

Classification by roll material:

Cast iron mill rolls

  • Alloy indefinite chilled cast iron rolls
  • Alloy chilled cast iron rolls
  • Alloy SG ductile cast iron roll
  • Pearlitic ductile cast iron roll
  • Bainite ductile cast iron roll
  • Centrifugal cast iron roll


Cast steel mill rolls   

  • Alloy cast steel rolls
  • Semi-steel roller
  • Graphite steel rolls
  • High-chromium steel roll
  • High-speed steel roll


Forging mill rolls

Sort by position on the rolling mill:

Work rolls
backup rolls

Intermediate roll

Product advantage

The world No. 1 in crude steel production steel plant, over 70% of the HSS for bar and wire are from us.

LMM high-speed steel rolls have higher steel passing per groove (times) due to their good wear resistance, which saves roll changing time, improves rolling mill operation rate, reduces roll consumption, and improve the overall efficiency of the factory.
Generally, the amount of steel passing in a single groove (times) is 3 to 5 times that of cast iron rolls.

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