Monitoring of a line system (1) in which a liquid medium (3) is guided in a line (2). The current pressure of the liquid medium (3) in the line (2) and in the associated current flow are sensed at sensing times. The two values are fed to a computing unit (5). The computing unit (5) calculates a theoretical flow of the liquid medium (3) in the line (2) from the sensed current pressure by taking into account a specified flow function. The flow function describes a physical relationship between the theoretical flow of the liquid medium (3) and the current pressure of the liquid medium (3). The computing unit (5) determines an individual degree of clogging on the basis of the current flow and the theoretical flow. On the basis of a number of determined individual degrees of clogging and by using stochastic methods, the computing unit (5) calculates an interval within which a degree of clogging of the line system (1) lies with a probability to be defined. The line system (1) is monitored by using the size of the interval and/or the position of the interval with respect to first limits for the degree of clogging that are defined beforehand.

Monitoring of a line system (1) in which a liquid medium (3) is guided in a line (2). The current pressure of the liquid medium (3) in the line (2) and in the associated current flow are sensed at sensing times. The two values are fed to a computing unit (5). The computing unit (5) calculates a theoretical flow of the liquid medium (3) in the line (2) from the sensed current pressure by taking into account a specified flow function. The flow function describes a physical relationship between the theoretical flow of the liquid medium (3) and the current pressure of the liquid medium (3). The computing unit (5) determines an individual degree of clogging on the basis of the current flow and the theoretical flow. On the basis of a number of determined individual degrees of clogging and by using stochastic methods, the computing unit (5) calculates an interval within which a degree of clogging of the line system (1) lies with a probability to be defined. The line system (1) is monitored by using the size of the interval and/or the position of the interval with respect to first limits for the degree of clogging that are defined beforehand.

The present invention is a secondary cooling method and a secondary cooling device for a casting product casted in a continuous casting machine, the continuous casting machine including, in a secondary cooling zone below a mold, a plurality of pairs of support rolls that support the casting product from both sides of the casting product in a thickness direction, a cooling device being disposed between support rolls adjacent to each other along a casting direction of the continuous casting machine, the cooling device including a coolant pipe that supplies a coolant, and a coolant guide plate with a flat plate shape for spreading the coolant on the casting product, the coolant guide plate being disposed parallel to and spaced in a perpendicular direction from a surface of the casting product. The coolant is supplied from a coolant supply port provided in the coolant guide plate to a gap between the casting product surface and the coolant guide plate, and the casting product is cooled using the coolant mainly in a transition boiling region.

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.

A method for setting a conicity of a die of a strand casting installation during a casting procedure, including the steps of: measuring temperature values along a centric measuring path running in a casting direction along an adjustably disposed die wall; measuring temperature values along a peripheral measuring path running in a casting direction along the adjustably disposed die wall, wherein the peripheral measuring path runs between the centric measuring path and a lateral periphery of the die wall, and a spacing of the peripheral measuring path from the lateral periphery of the die wall is smaller than a spacing of the centric measuring path from the other lateral periphery of the die wall; determining a centric temperature distribution curve along the centric measuring path from the temperature values measured along the centric measuring path; determining a peripheral temperature distribution curve along the peripheral measuring path from the temperature values measured along the peripheral measuring path; determining a first area under the centric temperature distribution curve, and a second area under the peripheral temperature distribution curve; determining a difference between the second area and the first area; and setting the conicity of the die taking into account the difference.

To provide a continuous casting method according to which a slab difficult for surface cracking to appear can be manufactured, in a first water cooling step, the slab is cooled so that only a surface temperature of corner parts is below Ar.sub.3 point, in a first recuperation step, the slab is recuperated so that the surface temperature of all the slab including the corner parts is no less than the Ar.sub.3 point, in a second water cooing step, the slab is cooled so that the surface temperature of all the slab including the corner parts is below the Ar.sub.3 point, and in a second recuperation step, the slab is recuperated so that the surface temperature of only a portion of the slab other than the corner parts is no less than the Ar.sub.3 point.

To provide a continuous casting method according to which a slab difficult for surface cracking to appear can be manufactured, in a first water cooling step, the slab is cooled so that only a surface temperature of corner parts is below Ar.sub.3 point, in a first recuperation step, the slab is recuperated so that the surface temperature of all the slab including the corner parts is no less than the Ar.sub.3 point, in a second water cooing step, the slab is cooled so that the surface temperature of all the slab including the corner parts is below the Ar.sub.3 point, and in a second recuperation step, the slab is recuperated so that the surface temperature of only a portion of the slab other than the corner parts is no less than the Ar.sub.3 point.

A method of manufacturing a round steel billet by continuous casting includes a local cooling step where inhomogeneous forced cooling is applied to a cast product during the continuous casting, and a rolling reduction step where rolling reduction is applied to the cast product in the opposite directions of the polar opposites by reduction rolls in the course from the completion of solidification to the completion of the recuperation of the cast product so that rolling reduction r which is a reduction ratio of a distance between middle points of the polar opposites is set to a value exceeding 0% and 5% or less.

Disclosed are a V-N microalloyed steel and a method for producing a V-N microalloyed and surface-crack-free continuous casting blank. The V-N microalloyed steel is composed of the following chemical components by mass percentage: 0.09%-0.13% of C, 0.1%-0.4% of Si, 1.0%-3.0% of Mn, less than or equal to 0.05% of P, less than or equal to 0.05% of S, 0.1%-0.4% of V, 0.011%-0.2% of N and the balance of Fe and unavoidable impurity elements. A continuous casting blank is subjected to component control according to the chemical components of the V-N microalloyed steel; and the production method therefor comprises converter smelting, LF refining and continuous casting steps in sequence. According to the present invention, by means of reasonable component design and smelting and continuous casting processes, the thermoplasticity of the continuous casting blank is improved, so that a high-temperature brittle region is prevented in a casting blank straightening region of the continuous casting blank or the thermoplasticity is good enough such that no surface crack appears, the casting blank is good in terms of surface quality and does not need to be cleaned, and the production efficiency is improved.

Disclosed are a V-N microalloyed steel and a method for producing a V-N microalloyed and surface-crack-free continuous casting blank. The V-N microalloyed steel is composed of the following chemical components by mass percentage: 0.09%-0.13% of C, 0.1%-0.4% of Si, 1.0%-3.0% of Mn, less than or equal to 0.05% of P, less than or equal to 0.05% of S, 0.1%-0.4% of V, 0.011%-0.2% of N and the balance of Fe and unavoidable impurity elements. A continuous casting blank is subjected to component control according to the chemical components of the V-N microalloyed steel; and the production method therefor comprises converter smelting, LF refining and continuous casting steps in sequence. According to the present invention, by means of reasonable component design and smelting and continuous casting processes, the thermoplasticity of the continuous casting blank is improved, so that a high-temperature brittle region is prevented in a casting blank straightening region of the continuous casting blank or the thermoplasticity is good enough such that no surface crack appears, the casting blank is good in terms of surface quality and does not need to be cleaned, and the production efficiency is improved.