A method for detecting a faulty cooling unit in a set of cooling units configured to provide a coolant to work rolls arranged to process a work item therebetween, the method including: varying the flow rates of the coolant ejected from a sub-set of the cooling units; in response to varying the flow rates, determining a flatness variation value of the work item for at least each of the cooling units in the sub-set of cooling units, the flatness variation value being indicative of the work item flatness variation downstream of the work rolls; and detecting a faulty cooling unit based on comparing the flatness variation values to a reference flatness variation value.

Provided is a hot press-formed member having excellent crack propagation resistance and ductility. The hot press-formed member includes: a base steel sheet and a zinc or zinc alloy plating layer on at least one surface of the base steel sheet. The base steel sheet contains, by wt %, carbon (C): 0.08-0.30%, silicon (Si): 0.01-2.0%, manganese (Mn): 3.1-8.0%, aluminum (Al): 0.001-0.5%, phosphorus (P): 0.001-0.05%, sulfur (S): 0.0001-0.02%, nitrogen (N): 0.02% or less, and a balance of iron (Fe) and other impurities. The hot press-formed member comprises 1-30 area % of retained austenite as a microstructure, and a Mn(wt %)/Zn(wt %) content ratio in an oxide layer of 0.5-1.2 μm in a thickness direction from a surface layer of the plating layer is 0.1 or more.

Provided is a hot press-formed member having excellent crack propagation resistance and ductility. The hot press-formed member includes: a base steel sheet and a zinc or zinc alloy plating layer on at least one surface of the base steel sheet. The base steel sheet contains, by wt %, carbon (C): 0.08-0.30%, silicon (Si): 0.01-2.0%, manganese (Mn): 3.1-8.0%, aluminum (Al): 0.001-0.5%, phosphorus (P): 0.001-0.05%, sulfur (S): 0.0001-0.02%, nitrogen (N): 0.02% or less, and a balance of iron (Fe) and other impurities. The hot press-formed member comprises 1-30 area % of retained austenite as a microstructure, and a Mn(wt %)/Zn(wt %) content ratio in an oxide layer of 0.5-1.2 μm in a thickness direction from a surface layer of the plating layer is 0.1 or more.

A cooling apparatus for cooling a metallic material has at least one cooling beam with a plurality of coolant application elements for applying the metallic material with a coolant. In order to be able to adapt such known cooling apparatuses even more precisely to different temperature distributions across the width of the metallic material to be cooled the density of the cross-sectional areas of the outlet openings of the coolant application elements in the width direction y of the cooling beam be distributed or dimensioned according to the amount of the slope of the distribution of the temperature T(y) of the metallic material across its width before the inlet under the cooling beam. A method for cooling a metallic material so includes determining a temperature distribution of the metallic material to be cooled and producing or selecting a cooling beam to match the temperature distribution of the metallic material.

A cooling apparatus for cooling a metallic material has at least one cooling beam with a plurality of coolant application elements for applying the metallic material with a coolant. In order to be able to adapt such known cooling apparatuses even more precisely to different temperature distributions across the width of the metallic material to be cooled the density of the cross-sectional areas of the outlet openings of the coolant application elements in the width direction y of the cooling beam be distributed or dimensioned according to the amount of the slope of the distribution of the temperature T(y) of the metallic material across its width before the inlet under the cooling beam. A method for cooling a metallic material so includes determining a temperature distribution of the metallic material to be cooled and producing or selecting a cooling beam to match the temperature distribution of the metallic material.

A cooling bar (1) for cooling rolled material (5) being moved in a transport direction (3) and in particular for reducing temperature differences in the temperature of the rolled material (5) transversely to the direction of transport (3). The cooling bar (1) has several full jet nozzles (11) by means of which a coolant beam of a coolant with an approximately constant jet diameter can be distributed to the rolling stock (5) in the direction of distribution (15). A cooling device has at least two cooling bars (1) of that type. The cooling bars extend transversely to a transport direction, one behind the other. Each cooling bar has a respective different pattern of jet nozzles and selection of applicable pattern of jet nozzles in their respective bars selectively cools the rolled material transversely to the transport direction.

A framework cooler (20) for cooling a steel strip (50), installed in a roller framework (11), in place of the work rolls (5) and their associated installation pieces (5a and 5b). The framework cooler (20) is sized to be installed into the roller framework (11) through the operator-side roller stands (1) of the roller framework (11). The cooler (20) includes a lower (21b) and an upper water tank (21a), each having a connection (22) for a coolant, and includes a plurality of cooling nozzles (23), or cooling tubes (23a) arranged in the depth direction (T) of the framework cooler (20) or at least one cooling slot (24) extending in the depth direction (T). The bottom and top sides of the steel strip (50) may be cooled.

A method for open-loop and/or closed-loop control of a heating of a cast or rolled metal product, includes the steps of determining the total enthalpy of the metal product from a sum of the free molar enthalpies (Gibbs energy) of all phases and/or phase fractions currently present in the metal product; determining a temperature distribution within the metal product by means of a dynamic temperature calculation model using the total enthalpy determined; and open-loop and/or closed-loop controlling of the heating of the metal product as a function of at least one output variable of the temperature calculation model.

A method for open-loop and/or closed-loop control of a heating of a cast or rolled metal product, includes the steps of determining the total enthalpy of the metal product from a sum of the free molar enthalpies (Gibbs energy) of all phases and/or phase fractions currently present in the metal product; determining a temperature distribution within the metal product by means of a dynamic temperature calculation model using the total enthalpy determined; and open-loop and/or closed-loop controlling of the heating of the metal product as a function of at least one output variable of the temperature calculation model.

The invention relates to a method for the open-loop and/or closed-loop control of a heating of a cast or rolled metal product, comprising the following steps: —determining the total enthalpy of the metal product from a total of the free molar enthalpies (Gibbs free energy) of all phases and/or phase fractions currently present in the metal product; —determining a temperature distribution within the metal product by means of a dynamic temperature calculation model by using the determined total enthalpy; and —open-loop and/or closed-loop controlling of the heating of the metal product according to at least one initial variable of the temperature calculation model.