A method for calculating a pass schedule for a stable rolling process in rolling at least a section of a metal strip in a rolling stand, comprising the following steps:
- i) providing input data to a pass schedule calculator, wherein the input data includes a predefined initial offset of a working roll relative to another roll in the rolling stand;
- and
- prior to and/or during the rolling process:
- ii) calculating a target horizontal force on the working roll by the pass schedule calculator running a process model of rolling, taking into account the input data;
- and
- iii) checking whether the target horizontal force calculated by the pass schedule calculator satisfies a predefined limit criterion;
- in response to determining that the target horizontal force satisfies the predefined limit criterion, setting the offset, on which the calculation of the target horizontal force was based, on the working roll and rolling the metal strip with the target horizontal force;
- or
- in response to determining that the target horizontal force does not satisfy the predefined limit criterion, repeating steps i), ii) and iii) with a changed offset (saw) of the working roll from a set of N available different offsets and with otherwise unchanged input data until it is determined in step iii) that the last calculated target horizontal force, taking into account the last changed offset, satisfies the limit criterion;
- upon determining that iterative repetition of steps i), ii) and iii), each with a change in the offset alone, does not result in the target horizontal force satisfying the limit criterion in step iii), applying the following a first modification:
- selecting an optimal offset from the set of N offsets with which the calculated target horizontal force best satisfies the limit criterion, and
- repeating steps i), ii) and iii)
- with a respectively changed draw on the metal strip on a feed side of the rolling stand from a set of L available different draws and/or
- with a respectively changed draw on the metal strip on an outlet side of the rolling stand from a set of M available different draws and with the optimal offset kept constant in each case and with otherwise unchanged input data,
- until it is determined in step iii) that the last calculated target horizontal force, taking into account the last changed draw, satisfies the limit criterion.