As sections of a rolled product (1) pass through a cooling path (2), they are initially cooled in a first cooling phase by front cooling devices (6). The sections are then not cooled in a subsequent second cooling phase. They are finally cooled again in a subsequent third cooling phase, by rear cooling devices (8) of the cooling path (2). A control device (10) of the cooling path receives in each case an initial energy value (EA) exhibited by the sections before they pass through the cooling path (2). The control device furthermore receives a target energy (E1*) and a target enthalpy (E2*). The control device (10) determines a first target cooling medium profile (K1*) on the basis of the initial energy value (EA) and the target energy (E1*). The control device controls the front cooling devices (6) in accordance with the first target cooling medium profile (K1*) while the respective section is passing through the front cooling devices (6). The control device (10) determines a second target cooling medium profile (K2) on the basis of an expected enthalpy for the respective section in the second cooling phase and the target enthalpy (E2*). The control device controls the rear cooling devices (8) in accordance with the second target cooling medium profile (K2*) while the respective section of the rolled product (1) is passing through the rear cooling devices (8).

A method for determining the temperature of a metal strip (1) inside a cooling apparatus (4) of a hot rolling installation is implemented by an electronic device (12). This method includes acquiring a temperature measure of a strip portion at a current time instant; estimating, at the current time instant, a heat flux extracted from the strip portion inside the cooling apparatus according to a thermal model, and computing a strip portion temperature at a next time instant from the acquired temperature measure and the estimated extracted heat flux. The thermal model models an air cooling of the strip portion, a coolant header cooling of the strip portion by a coolant header and a remaining coolant cooling of the strip portion, wherein for the coolant header cooling the model models both an impingement cooling of the strip portion and a parallel flow cooling of the strip portion.

A method for determining the temperature of a metal strip (1) inside a cooling apparatus (4) of a hot rolling installation is implemented by an electronic device (12). This method includes acquiring a temperature measure of a strip portion at a current time instant; estimating, at the current time instant, a heat flux extracted from the strip portion inside the cooling apparatus according to a thermal model, and computing a strip portion temperature at a next time instant from the acquired temperature measure and the estimated extracted heat flux. The thermal model models an air cooling of the strip portion, a coolant header cooling of the strip portion by a coolant header and a remaining coolant cooling of the strip portion, wherein for the coolant header cooling the model models both an impingement cooling of the strip portion and a parallel flow cooling of the strip portion.

A hot-rolled steel sheet is cooled by jetting cooling water from spray nozzles to a steel sheet conveyance region in a width direction of the steel sheet conveyance region. The steel sheet conveyance region is a region that the hot-rolled steel sheet occupies on conveyor rolls, a pair of spray nozzles is arranged on both lateral sides in the width direction of the steel sheet conveyance region, and a plurality of spray nozzle pairs are aligned in a conveyance direction of the hot-rolled steel sheet. In regard to a collision region of cooling water jetted from the spray nozzle at the steel sheet conveyance region, a far end in a jet direction is positioned at an end of the steel sheet conveyance region, and a near end is positioned on an inner side of the steel sheet conveyance region. In the spray nozzle pair, the near ends of two collision regions coincide in the width direction to form a meeting.

Provided is a cooling device, where a hot-finish-rolling mill includes a plurality of nozzles which spray cooling water toward one of or both of upper and lower surfaces of a hot-rolled steel sheet just after rolled by rolling stands, the nozzles are provided on the inside of the upper and lower guides or adjoining to the guides on a downstream side, and a nozzle spray distance changes depending on a position of the nozzle in a rolling direction, wherein a spray angle of the nozzle at a position whose nozzle spray distance is the largest is smaller than a spray angle of the nozzle at a position whose nozzle spray distance is the smallest, and the spray angle of the nozzle becomes the same or smaller as the nozzle spray distance becomes large.

Provided is a cooling device, where a hot-finish-rolling mill includes a plurality of nozzles which spray cooling water toward one of or both of upper and lower surfaces of a hot-rolled steel sheet just after rolled by rolling stands, the nozzles are provided on the inside of the upper and lower guides or adjoining to the guides on a downstream side, and a nozzle spray distance changes depending on a position of the nozzle in a rolling direction, wherein a spray angle of the nozzle at a position whose nozzle spray distance is the largest is smaller than a spray angle of the nozzle at a position whose nozzle spray distance is the smallest, and the spray angle of the nozzle becomes the same or smaller as the nozzle spray distance becomes large.

A method for determining the temperature of a metal strip (1) inside a cooling apparatus (4) of a hot rolling installation is implemented by an electronic device (12). This method includes acquiring a temperature measure of a strip portion at a current time instant; estimating, at the current time instant, a heat flux extracted from the strip portion inside the cooling apparatus according to a thermal model, and computing a strip portion temperature at a next time instant from the acquired temperature measure and the estimated extracted heat flux. The thermal model models an air cooling of the strip portion, a coolant header cooling of the strip portion by a coolant header and a remaining coolant cooling of the strip portion, wherein for the coolant header cooling the model models both an impingement cooling of the strip portion and a parallel flow cooling of the strip portion.

A method for determining the temperature of a metal strip (1) inside a cooling apparatus (4) of a hot rolling installation is implemented by an electronic device (12). This method includes acquiring a temperature measure of a strip portion at a current time instant; estimating, at the current time instant, a heat flux extracted from the strip portion inside the cooling apparatus according to a thermal model, and computing a strip portion temperature at a next time instant from the acquired temperature measure and the estimated extracted heat flux. The thermal model models an air cooling of the strip portion, a coolant header cooling of the strip portion by a coolant header and a remaining coolant cooling of the strip portion, wherein for the coolant header cooling the model models both an impingement cooling of the strip portion and a parallel flow cooling of the strip portion.

A method for cooling a rolled product in a cooling section which is located upstream of a finishing train of a hot rolling mill. The cooling section includes a cooling device which can deliver a coolant flow of a coolant onto a rolled product surface of the rolled product. In the method, a coolant flow is delivered, by means of each cooling device and in each cooling section pass, onto the rolled product surface, which flow is set to a set value that is assigned to the relevant cooling device for the cooling section pass. The set values for a cooling section pass are determined in a simulation of the cooling section pass so that surface temperatures, determined in the simulation, of the rolled product surface upon leaving active regions of the cooling device do not exceed a minimum value for a surface temperature of the rolled product surface.

A method for cooling a rolled product in a cooling section which is located upstream of a finishing train of a hot rolling mill. The cooling section includes a cooling device which can deliver a coolant flow of a coolant onto a rolled product surface of the rolled product. In the method, a coolant flow is delivered, by means of each cooling device and in each cooling section pass, onto the rolled product surface, which flow is set to a set value that is assigned to the relevant cooling device for the cooling section pass. The set values for a cooling section pass are determined in a simulation of the cooling section pass so that surface temperatures, determined in the simulation, of the rolled product surface upon leaving active regions of the cooling device do not exceed a minimum value for a surface temperature of the rolled product surface.