Controlling the Electric Drives of the Reversing Rolling Stand Rolls of a Rolling Mill to Form a Curvature at the Workpiece Front End

Abstract

The article defines the specifications of a reversing rolling stand of the 5,000 mm plate mill. It describes the mechanism of vertical bending of a workpiece front end (the socalled ski-end formation) by the mismatch of speed of the top and bottom rolls (asymmetric rolling). A diagram of the electric drive control system operating during the ski-end formation is given, functions of the load division controller are specified. Oscillograph records of speeds and drive torques of the top and bottom rolls are considered. A slow response is revealed in a parameter mode. A method of the electric drive control, which ensures a forced reduction of the specified speed mismatch after gripping, is presented. The structure of a mathematical model, which includes the ski-end formation block and the engine torque distribution model, is analyzed. The simulation results for rolling patterns corresponding to the project and developed algorithms of ski-end formation and load division are provided. A reduction of difference in the engine torques and the time required for their equalization is confirmed. The oscillograph records of the electric drives coordinates when implementing the developed method are given. The technical effectiveness of this method implementation on the 5,000 mm mill is verified.