Reducing tensile force-induced changes in thickness during rolling

Abstract

A position controller that controls an actuator that sets a roll gap of a roll stand by determining an actuating variable (q) for the actuator as a function of a resulting position target value (s*) and a position actual value(s) of the actuator. The (s*) is determined with a resulting base target value (s1*), which is determined as the sum of an initial base target value (s0*) and an additional target value (δs1*), which is determined by a determination element with an inlet-end actual tension (ZE) and an inlet-end reference tension (ZER) and/or with an outlet-end actual tension (ZA) and an outlet-end reference tension (ZAR). Instead of (ZE) and (ZA), the corresponding target tensions (ZE*, ZA*) of corresponding tension control operations can also be used. However, in both cases, (ZER) and (ZAR) are variables that differ from (ZE*) and (ZA*).

1 . An operating method for a roll stand for rolling flat metal rolling stock,
 determining with a position regulator that regulates positioning of an actuator that sets a roll gap of the roll stand, an actuating variable (q) for the actuator as a function of a resulting position target value (s*) and a position actual value (s) of the actuator; and activating, with the position regulator, the actuator accordingly,   wherein the resulting position target value (s*) is determined by use of a resulting base target value (s 1 *),   wherein the resulting base target value (s 1 *) is determined as the sum of an initial base target value (s 0 *) and an additional target value (δs 1 *),   wherein the additional target value (δs 1 *) is determined by a determination element by the use of an inlet-side actual tension (ZE), or a corresponding target tension (ZE*) of an inlet-side tension regulating system, and an inlet-side reference tension (ZER) and/or by the use of an outlet-side actual tension (ZA), or a corresponding target tension (ZA*) of an outlet-side tension regulating system, and an outlet-side reference tension (ZAR), and   wherein the inlet-side reference tension (ZER) is a different variable from the inlet-side target tension (ZE*) and/or the outlet-side reference tension (ZAR) is a different variable from an outlet-side target tension (ZA*).   
     
     
         2 . The operating method as claimed in  claim 1 , wherein the roll stand is operated by regulating the roll gap. 
     
     
         3 . The operating method as claimed in  claim 1 , wherein the inlet-side tension regulating system acts on a roll circumferential speed (vU) at which the flat rolling stock is rolled in the roll stand, and/or on a feed speed (vZ) at which the flat rolling stock exits a device arranged upstream from the roll stand, and/or in that the outlet-side tension regulating system acts on the roll circumferential speed (vU) and/or on a discharge speed (vA) at which the flat rolling stock enters a device arranged downstream from the roll stand. 
     
     
         4 . The operating method as claimed in  claim 1 , wherein the additional target value (δs 1 *) is determined by the determination element on the basis of the product of an inlet-side sensitivity (SE) and the difference between the inlet-side actual tension (ZE) or the corresponding target tension (ZE*) and the inlet-side reference tension (ZER) and/or on the basis of the product of the outlet-side sensitivity (SA) and the difference between the outlet-side actual tension (ZA) or the corresponding target tension (ZA*) and the outlet-side reference tension (ZAR). 
     
     
         5 . The operating method as claimed in  claim 4 , wherein the inlet-side sensitivity (SE) and/or the outlet-side sensitivity (SA) are specified for the determination element by a higher-order control device. 
     
     
         6 . The operating method as claimed in  claim 5 , wherein the inlet-side sensitivity (SE) and/or the outlet-side sensitivity (SA) are determined by the higher-order control device as part of a pass schedule calculation by analysis of a rolling model which describes the rolling procedure in the roll stand based on mathematical physical equations. 
     
     
         7 . The operating method as claimed in  claim 1 , wherein the inlet-side reference tension (ZER) and/or the outlet-side reference tension (ZAR) are specified for the determination element by a higher-order control device. 
     
     
         8 . The operating method as claimed in  claim 7 , wherein the higher-order control device
 determines the initial base target value (s 0 *) and the inlet-side target tension (ZE*) and/or the outlet-side target tension (ZA*) on the basis of a target thickness (d*) with which the flat rolling stock is to exit the roll stand and the inlet-side reference tension (ZER) and/or the outlet-side reference tension (ZAR),   specifies the initial base target value (s 0 *) of a regulating unit comprising the position regulator and the determination element, and   specifies the inlet-side target tension (ZE*) for a front tension regulator which regulates the inlet-side actual tension (ZE) to the inlet-side target tension (ZE*) and/or the outlet-side target tension (ZA*) for a rear tension regulator which regulates the outlet-side actual tension (ZA) to the outlet-side target tension (ZA*).   
     
     
         9 . The operating method as claimed in  claim 1 , wherein the resulting position target value (s*) is determined at least during the rolling of a central portion of the rolling stock by the use of a correction value (δs 2 *) determined by the use of an actual rolling force (F). 
     
     
         10 . The operating method as claimed in  claim 9 , wherein the resulting base target value (s 1 *) is taken into account as part of the determination of the correction value (δs 2 *) in addition to the actual rolling force (F). 
     
     
         11 . The operating method as claimed in  claim 1 , wherein the resulting position target value (s*) is determined at least during the rolling of a head of the rolling stock and/or a tail of the rolling stock without the use of an actual rolling force (F). 
     
     
         12 . The operating method as claimed in  claim 1 , wherein the resulting position target value (s*) is determined by the use of the deviation of a thickness (d) of the rolling stock, measured at the outlet side of the roll stand, from a target thickness (d*). 
     
     
         13 . A control system for a roll stand for rolling a flat rolling stock, wherein the control system is formed by hardware blocks and/or software programs in such a way that during operation it implements an operating method as claimed in  claim 1 . 
     
     
         14 . A rolling unit for rolling flat metal rolling stock, wherein the rolling unit has a roll stand for rolling the flat rolling stock and a control system as claimed in  claim 13 .