The board thickness control manner null in high-temperature finish

摘要

PURPOSE:To improve the accuracy of sheet thickness control by grasping a position of an inside min. diameter part of a coil and predicting a temp. drop amount of the part and correcting a screw down position in a finishing rolling mill based on the temp. drop amount and data decided by types of steel. CONSTITUTION:A hot piece detector (HMD) 4 is installed between a hot sheet bar coil 1 and a crop shear 5 and pinch rolls 7 is provided with a pulse generator 6. A tracking computer 9 grasps a position of a coil inside min. diameter part 2 generating temp. drop through detection signals of the HMD 4 and signal of the generator 6. A temp. drop amount T of the part 2 is predicted by use of a sheet bar winding and rewinding duration time (t), sheet surface temp. TRD in the outlet side of a rough rolling mill. The part 2 is accurately tracked by the computer 9 and compression position in a finishing mill group 8 is corrected based on the temp. drop amount TRD and data decided by types of steel. Hence, the accuracy of sheet thickness control is improved.