JPS5475462A - Controller for rolling reduction - Google Patents

Abstract

PURPOSE:To make the outside diameter of the rolled pipe to meet the aimed value uniformly, properly, and quickly, by removing the deviation of the outside diameter of the rolled pipe from the aimed outside diameter, caused by such primary factor as the imperfection of initial set value for the rolling reduction, etc. CONSTITUTION:Assume that the rolling reduction S1-S7 of the stands No. 1-7 in the sizing mill 2 are settled on the relation S1>=S2>=...S6>=S7. Under this condition, under this condition, the outside diameter of the rolled pipe is measured; if there exists some deviation DELTA d between the measured outside diametr and the aimed value, the correction (that is to say-DELTAd) must be given to the rolling reduction in each stand so as to cancel this deviation DELTAd before entering into next rolling pass for the pipe. First of these seven stands, the rolling reduction of the final stand No. 7 is corrected. If the quantity of correction of rolling reduction necessary for correcting the deviation DELTAd of the out- side diameter is taken as DELTAS7, the relation DELTAS7=C- DELTAd must be satisfied, and the rolling-reduction-control-output newly given by the computer/controller 5 must be given by S'7=S7-DELTAS7. After next rolling pass for the pipe under thus correctes conditions, if some deviation is again found, the similar computationis carried out for correcting the rolling reduction in the next pass.