JPS5659533A - Coiling method for cold rolled strip - Google Patents

Abstract

PURPOSE: To make the coil's surface pressure constant at coiling after the annealing process in order to prevent the generation of the flaws in the coil, and to improve the yield, by partially changing the coiling tension of the cold rolled steel strip at coiling into the coil.

CONSTITUTION: At starting the coiling of the steel strip 1 running out of the cold rolling mill 2, the coiling tension is detected by the detector 3, and the motor torque of the coiler 5 is controlled by the controller 4. And the strip is coiled with the tension 50W200% larger than the ordinary coiling tension T₂, and next, the strip is coiled with the ordinary coiling tension T₂ during the coil thickness grows from C₁ to C₂. Next, after the coil thickness C₂ becomes 20W40% of the scheduled total coil thickness C₄, the strip is coiled with constant tension 0.5W1,5kg/mm² lower than the ordinary coiling tension T₂. After the coil thickness C₃, the tension is again returned to the ordinary coiling tension T₂ and is continued until the final thickness. The reason of above limitation of the reduction of the coiling tension to 0.5W1.5kg/mm² is as followes; if the reduction of the coiling tension is less than 0.5kg/mm² during the cooling process following to the tight coil annealing process, the seizure of the strip due to the shrinkage cannot be effctively prevented; and if it is 1.5kg/mm², the strip is hurted by the too tight coiling.

COPYRIGHT: (C)1981,JPO&Japio