CONTROL METHOD OF TAPER RATIO OF STRIP ON FINISHING MILL

摘要

PURPOSE: A control method of taper ratio of strip on finishing mill is provided to minimize fluctuation of coiling tension generated during final stand metal out in finishing mill by providing a control means capable of varying taper reduction ratio by accurately predicting residual weight. CONSTITUTION: The method comprises first step of calculating weight of non-coiled strip by the following expression when a tail part of the strip is at a point of fi stand metal out: £fidc = Wf{(i) to (i+1)} + Wf{(i+1) to (i+2)} + Wf{(i+2) to (i+3)} + Wf{(i+n-1) to (i+n)} + Wrot + Wprm|; second step of calculating completed coiling diameter of coil by the following expression so that taper tension is completed when the tail part of the strip is at a point of fi stand metal out by using the weight of the strip calculated by the first step: £Dfidc = {(total weight of coil - Wfidc)/(densityxπxstrip widthxspace factor(porosity)) + (diameter of mandrel/2)¬2}¬0.5 x 2|; and third step of calculating taper reduction ratio varied by the following expression according to unit weight of the coil by using the completed coiling diameter of the coil calculated by the second step: £taper reduction ratio = (initial tension set value - minimum tension set value)/(completed coiling diameter - diameter of taper tension initiating coil)|.