Method for the open-loop or closed-loop control of the temperature of a steel strip during hot working in a hot strip mill

A method for open-loop or closed-loop controlling a temperature of a steel strip with alloying elements

• in % by weight
• min
• max
• C
• 0
• 1
• Mn
• 0
• 2.5
• in hot forming of a preliminary product with a thickness between dV≥1 mm and dV≤300 mm into a hot strip with a hot strip thickness dWB≤25 mm and a hot strip width between bWB≥900 mm and bWB≤2100 mm, a target coiling temperature TH≥30° C. to TH≤750° C. in a hot strip mill, having at least one furnace for heating and temperature homogenization of the preliminary product, at least one roll stand for hot rolling the preliminary product, a cooling section for targeted cooling of the hot strip after forming, and a coiler for winding the hot strip to form a coil, with each individual unit having its own open-loop or closed-loop controller for the specified target values,
• wherein
• on a data processing system assigned to the hot strip mill, a superordinate process model exchanges and stores online target and actual values, including times, speeds, temperature, cooling rates and heating rates, with at least two open-loop or closed-loop controllers of the units;
• the superordinate process model, based on the exchanged target and actual values and stored values and using subordinate process models, predetermines the temperature of the steel strip online for at least one point before the hot strip is coiled;
• and
• the superordinate process model determines new target value specifications of the units at this point in case of deviations of the predetermined temperature from a target value specification, and transfers them to the open-loop or closed-loop controller of the unit in order to comply with the target value specification for the temperature of the steel strip;
• the determination of the new target value specifications is carried out by using an optimization algorithm including at least one subordinate process model;
• and
• controlling the temperature of the strip with the alloying elements using the new target value specification in response to the predetermined temperature deviations.