Dynamic Load Limitation in Electromechanical Systems of the Rolling Mill Stand during Biting

Abstract

The paper describes the characteristics of the reversing 5000 rolling mill stand from Magnitogorsk Iron and Steel Works (MMK PJSC). Causes for intolerable dynamic loads during biting are noted. It is shown in the text that one of such causes is angular plays in spindle joints. The paper considers the mechanism for creation of impact loads in case of angular play lock. Also, the paper describes a well-known method for enforced angular play lock before biting, by means of preliminary electric drive boost. It is shown that this method cannot fully compensate the dynamic torque. The reason for this is torque overcontrol during shock loading which depends on how the automatic electric drive speed control system is configured. The paper provides a brief description of the designed math model, presents modeling results proving the conclusion. Also, the paper suggests a method for limiting the dynamic torque through preventive acceleration (boosting) to compensate the value of a dynamic speed control error. Engine speed and torque oscillograms recorded during implementing this method on rolling mill 5000 are presented. Dynamic torque reduction and speed control error are confirmed. Focus areas for further advancements are drawn up.