Method for producing a rolled product with a box profile

Abstract

A control device that receives actual variables (I) of a flat rolled product before rolling and target variables (Z) of the rolled product after rolling in a rolling mill. The target variables (Z) include at least one profile value (C) of the rolled product, which relates to a predetermined spacing (a) from the edges of the rolled product. The control device determines an ideal contour shape (ci) on the basis of the target variables (Z). On the basis of the actual variables (I) and the ideal contour shape (ci), the device uses a model of the rolling mill to determine target values (COM) for manipulated variables for the roll stands of the rolling mill. The device transfers the target values (COM) to the roll stands, such that the rolled product is rolled in the rolling mill in consideration of the target values (COM).

1 . An operating method for a rolling line comprising a number of rolling stands for rolling a flat rolled product, wherein a control device of the rolling line:
 accepts actual variables of the flat rolled product before the rolling of the flat rolled product in the rolling line and target variables (Z) of the flat rolled product after the rolling of the flat rolled product in the rolling line, wherein the target variables (Z) comprise at least one desired profile value (C) of the flat rolled product, which characterizes the deviation of the thickness (d) of the flat rolled product at a predetermined distance (a) from the edges of the flat rolled product from a center thickness (d 0 ), which the flat rolled product has in the center between the edges,   determines an ideal contour course (ci) of the flat rolled product over the rolled product width (b) on the basis of the target variables (Z),   determines setpoint values (COM) for manipulated variables for the rolling stands of the rolling line on the basis of the actual variables (I) of the flat rolled product and the ideal contour course (ci) using a model of the rolling line, and   transmits the determined setpoint values (COM) to the rolling stands of the rolling line so that the flat rolled product is rolled in the rolling line in consideration of the transmitted setpoint values (COM),   
       wherein the control device determines the setpoint values (COM) for the manipulated variables by means of the model such that a contour course (ce) expected for the flat rolled product after the rolling of the flat rolled product in the rolling line is exclusively approximated as well as possible to the ideal contour course (ci) in an initial center area when viewed over the rolling product width (b), which extends toward the edges of the flat rolled product up to initial area boundaries, which have a distance greater than the predetermined distance (a) from the edges of the flat rolled product, or the expected contour course (ce) is also approximated to the ideal contour course (ci) outside the initial center area in addition to the initial center area but only insofar as it is possible without impairing the approximation of the expected contour course (ce) to the ideal contour course (ci) in the initial center area. 
     
     
         2 . The operating method as claimed in  claim 1 , wherein the control device accepts the initial area boundaries or the distance (a 1 ) of the initial area boundaries from the edges of the flat rolled product. 
     
     
         3 . The operating method as claimed in  claim 1 , wherein the control device determines the initial area boundaries or the distance (a 1 ) of the initial area boundaries from the edges of the flat rolled product using the actual variables (I) of the flat rolled product before the rolling of the flat rolled product in the rolling line and/or the predetermined distance (a). 
     
     
         4 . The operating method as claimed in  claim 1 , wherein the control device:
 checks whether the expected contour (ce) is convex or not,   in the case of a convex contour, enlarges the initial center area or reduces the distances (a 1 ) of the initial area boundaries from the edges of the flat rolled product, and   in the case of a nonconvex contour, reduces the initial center area or increases the distances (a 1 ) of the initial area boundaries from the edges of the flat rolled product.   
     
     
         5 . The operating method as claimed in  claim 1 , wherein the control device determines the ideal contour course (ci) in that it defines the coefficients of a polynomial describing the ideal contour course (ci), in particular a monomial, such that the ideal contour course (cr) corresponds as well as possible with the target variables (Z). 
     
     
         6 . The operating method as claimed in  claim 1 , wherein the control device:
 accepts measured variables (M) characteristic for an actual contour course (ct) of the flat rolled product after the rolling of the flat rolled product in the rolling line,   determines a contour function (cf′) extending at least over a final center area such that the contour function (cf′) is approximated as well as possible to the actual contour course (ct) in the final center area, and   determines a modeled profile value (C′) of the flat rolled product by computer on the basis of the contour function (cf′) and utilizes the modeled profile value (C′) in the scope of a model adaptation, by means of which the control device adapts the model of the rolling line, as the profile value which characterizes the deviation of the thickness (d) at the predetermined distance (a) from the edges of the flat rolled product from the center thickness (d 0 ) of the flat rolled product.   
     
     
         7 . The operating method as claimed in  claim 6 , wherein the control device determines coefficients of the contour function (cf′) to determine the contour function (cf′) and in that the control device determines the modeled profile value (C′) on the basis of the coefficients of the contour function (cf′). 
     
     
         8 . The operating method as claimed in  claim 6 , wherein the control device;
 checks whether the contour function (cf′) is convex or not in the final center area,   enlarges the final center area in the case of a convex contour function, and   reduces the final center area in the case of a nonconvex contour function.   
     
     
         9 . The operating method as claimed in  claim 1 , wherein the control device:
 accepts measured variables (M) characteristic for an actual contour course (ct) of the flat rolled product during the rolling of the flat rolled product in the rolling line,   determines a contour function (cf′) extending at least over a final center area such that the contour function (cf′) approximates the actual contour course (ct) in the final center area as much as possible, and   tracks the setpoint values (COM) for the manipulated variables on the basis of the deviation of the contour function (cf′) from the ideal contour course (ci).   
     
     
         10 . The operating method as claimed in  claim 9 , wherein the control device determines coefficients of the contour function (cf′) to determine the contour function (cf′). 
     
     
         11 . The operating method as claimed in  claim 9 , wherein the control device:
 checks whether the contour function (cf′) is convex or not in the final center area,   enlarges the final center area in the case of a convex contour function, and   reduces the final center area in the case of a nonconvex contour function.   
     
     
         12 . The operating method as claimed in  claim 1 , wherein the control device activates a cooling device, by means of which the working rollers of at least one of the rolling stands are cooled as a function of the location (x) when viewed over the rolled product width (b) such that the contour course (ce) expected for the flat rolled product after the rolling of the flat rolled product in the rolling line is approximated from the initial area boundaries toward the edges of the flat rolled product as much as possible to the ideal contour course (ci) insofar as it is possible without impairing the approximation of the expected contour course (ce) to the ideal contour course (ci) in the initial center area. 
     
     
         13 . A computer program product which comprises a non-transitory medium having recorder thereon machine code that is executable by a control device for a rolling line for rolling a flat rolled product, wherein the execution of the machine code by the control device causes the control device to operate the rolling line according to an operating method as claimed in  claim 1 . 
     
     
         14 . A control device for a rolling line for rolling a flat rolled product, wherein the control device is a software-programmable control device and is programmed using a computer program, so that it operates the rolling line according to an operating method as claimed in  claim 1 . 
     
     
         15 . A rolling line for rolling a flat rolled product,
 wherein the rolling line has a number of rolling stands, by means of which the flat rolled product is rolled,   wherein the rolling line has a control device as claimed in claim  14 .