How to avoid overload of strip rollers?

Reasonable setting and control of rolling parameters

Accurate calculation of rolling forces

• Before rolling, it is necessary to accurately calculate the rolling force using a professional rolling force calculation formula based on factors such as the material of the strip (such as steel, aluminum, copper and other metals and their alloys), thickness (initial thickness and target thickness), width, and the material and size of the strip roller.

  After calculating the reasonable rolling force, it is accurately set in the rolling mill control system to ensure that the rolling force does not exceed the rated load capacity of the strip roller.

• For some new materials or strips with special specifications, when there is no ready-made calculation formula to refer to, the appropriate rolling force range can be determined by experimental rolling or computer simulation.

  For example, when rolling new composite strips, a small-scale trial rolling is carried out first, and the reasonable rolling force is adjusted and determined based on the reaction of the strip rollers (such as deformation, vibration, etc.) and the rolling quality of the strip during the trial rolling.

Optimize rolling speed and tension control

• According to the performance of the strip roller and the material characteristics of the strip, select the appropriate rolling speed.

  Generally speaking, the rolling speed of harder and thicker strips should be appropriately reduced to reduce friction and heat generation.

  In actual operation, you can refer to the speed recommendations provided by the equipment manufacturer and make adjustments in combination with the on-site rolling quality feedback.

  For example, when hot rolling alloy steel strips, due to the high hardness of alloy steel, the initial rolling speed can be set to a lower value, and then gradually increase the rolling speed as the strip gradually becomes thinner and the temperature decreases appropriately.

• For tension control, the reasonable tension range should be determined by combining theoretical calculation and practical experience according to the size and material of the strip.

  During the rolling process, the tension sensor is used to monitor the tension change in real time, and the tension is stabilized within the set range through the automatic control system.

  For example, in the production of cold-rolled aluminum strips, the appropriate front and rear tensions are calculated according to the width and thickness of the aluminum strip. During the rolling process, the tension control system is used to keep the aluminum strip between the strip rollers at a stable tension to avoid excessive tension causing overload of the strip rollers.

Enhance equipment monitoring and troubleshooting capabilities

Installing advanced monitoring systems

• High-precision sensors are installed on the rolling mill to monitor the operating status of the strip rolls in real time.

  These sensors include pressure sensors (monitoring rolling force), displacement sensors (monitoring roll deformation), vibration sensors (monitoring operating stability) and temperature sensors (monitoring roll and bearing temperature).

  For example, the pressure sensor can accurately measure the actual rolling force during the rolling process and transmit the data to the control system. When the rolling force approaches the rated value of the strip roll, the control system will sound an alarm to remind the operator to adjust the rolling parameters.

• The data collected by the sensor is analyzed in real time using the data acquisition system and data analysis software. By establishing a mathematical model, it is possible to predict whether the strip roller has an overload trend.

  For example, by analyzing the changing trend of vibration data and temperature data, when it is found that the vibration amplitude suddenly increases or the temperature rises sharply, the system can determine that it may be caused by excessive rolling force or other abnormal conditions, so as to take measures in advance to avoid overloading of the strip roller.

Handle equipment failures and abnormal situations promptly

• When the strip is detected to be deviating, the automatic correction system should be started immediately.

  The automatic correction system can return the strip to the correct rolling position by adjusting the inclination of the roll gap or moving the guide plate.

  If there is no automatic correction system or the automatic correction fails, the operator should intervene manually in time, stop rolling, check and adjust the equipment to prevent the strip from continuously applying uneven pressure on one side of the roller.

• In case of foreign matter entering the rolling area, install foreign matter detection devices such as metal detectors.

  When foreign matter is detected, the emergency shutdown procedure is immediately triggered, and the foreign matter is cleaned up and the strip rolls are checked for damage.

  Before restarting, ensure that there are no foreign matter in the rolling area and perform necessary debugging and inspection on the equipment.

Scientifically plan production tasks and processes

Reasonable arrangement of strip rolling sequence

• According to the load-bearing capacity of the strip roller and the difficulty of rolling different strips, the order of rolling tasks should be arranged reasonably.

  Generally, thinner and softer strips are rolled first, and then thicker and harder strips are rolled.

  For example, in a day’s production tasks, if there are tasks of cold-rolling thin aluminum plates and cold-rolling thick steel plates, the rolling of cold-rolled thin aluminum plates should be arranged first, so that the strip rollers can start working under a relatively low load, and the equipment can be debugged and preheated during the rolling of thin aluminum plates, and then the thick steel plates can be rolled, which is conducive to reducing the risk of overload of the strip rollers.

Balance equipment load

• For rolling mill production lines with multiple sets of strip rollers, production tasks should be evenly distributed to avoid overuse of a set of strip rollers.

  According to the performance and status of each set of strip rollers, the strip tasks of different specifications and materials should be reasonably distributed to each rolling mill unit.

  For example, in a large steel rolling workshop, there are rolling mills of different models and specifications. According to factors such as the diameter, material and rated load of the strip rollers, the rolling tasks of thick and thin strips should be reasonably distributed to each rolling mill to ensure that the working load of each strip roller is within a reasonable range.

Rolling mill rolls