Provided is a meniscus flow control device includes: a meniscus flow detection unit for detecting, in a meniscus flow form of molten steel, relative temperature values for positions measured by temperature measurers, and relatively comparing the temperature values measured by the temperature measurers to thereby determine the flow state of the molten steel meniscus to be normal or abnormal; a magnetic field generation unit, installed outside a mold, for generating a magnetic field and controlling the flow of the molten steel by the magnetic field; and a flow control unit for maintaining the operation of the magnetic field generation unit in the current state when the meniscus flow state detected by the meniscus flow detection unit is determined to be normal, and for controlling the magnetic field generation unit to adjust the meniscus flow to be normal when the detected meniscus flow state is determined to be abnormal.

A steel sheet having a specified chemical composition and a tensile strength of 1,320 MPa or more, and methods for producing the steel sheet. The steel sheet has a specified microstructure including martensite and bainite, the total area fraction of the martensite and the bainite being 95% or more and 100% or less, the balance being one or more selected from ferrite and retained austenite. The forumulae [% Ti]+[% Nb]>0.007 and [% Ti]×[% Nb].sup.2≤7.5×10.sup.−6 are satisfied in the chemical composition.

Provided are a method and a system for a slag thickness detection and a slag-adding prediction. The method includes: acquiring real-time measurement data and real-time auxiliary data of a slag point on a surface of a protective slag layer of a casting mold; calculating a real-time slag thickness value corresponding to the slag point by using the real-time measurement data and the real-time auxiliary data of the slag point; and predicting a location on the surface of the protective slag layer where a slag-adding is to be performed and a slag-adding time when the slag-adding is to be performed based on a change in the real-time slag thickness value corresponding to the slag point by taking a preset slag thickness value as a reference.

An apparatus for the automatic startup of a continuous casting line, including a vessel which is connected to a tip by means of a gate, the tip feeding a casting housing. The apparatus includes a laser device which measures the level of the metal within the vessel, a level control device, which adjusts the introduction of liquid metal into the vessel, a gate actuator to control the gate for providing a barrier between the vessel and the tip, a transducer for the temperature of the metal inside the vessel, and a PLC which receives data from the temperature transducer and from the laser device to control the level control device and the gate actuator, so as to adjust the vessel metal level to ensure a correct and continuous flow of metal toward the casting cylinders, in order to avoid poor diffusion of the metal inside the tip.

An apparatus for the automatic startup of a continuous casting line, including a vessel which is connected to a tip by means of a gate, the tip feeding a casting housing. The apparatus includes a laser device which measures the level of the metal within the vessel, a level control device, which adjusts the introduction of liquid metal into the vessel, a gate actuator to control the gate for providing a barrier between the vessel and the tip, a transducer for the temperature of the metal inside the vessel, and a PLC which receives data from the temperature transducer and from the laser device to control the level control device and the gate actuator, so as to adjust the vessel metal level to ensure a correct and continuous flow of metal toward the casting cylinders, in order to avoid poor diffusion of the metal inside the tip.

A heat flux derivation unit (202) derives a value q.sub.y of a y-axis direction component of a heat flux vector. A molten metal surface level derivation unit (203) derives, as a molten metal surface level, a position where the absolute value of the value q.sub.y of the y-axis direction component of the heat flux vector whose y-axis component vector is in a direction opposite to a casting direction is maximum.

The measuring device includes: a detecting section including a coil which detects a change in a value of impedance caused by a change in a mold level; an amplifying section which amplifies an output of the detecting section; a pre-pouring calibration section which determines a reference value of a positive feedback ratio of the amplifying section in environmental conditions before pouring of molten metal; and a mold oscillation signal calibration section which obtains a standard value of difference in an output of the measuring device, the standard value of difference corresponding to a known value of amplitude of mold oscillation when the positive feedback ratio is the reference value, obtains a deviation of measurement based on a difference between the maximum value and the minimum value of the output in mold oscillation and the standard value, and corrects the positive feedback ratio within a predetermined range including the reference value.

A computer determines a thickness and/or a temperature of a metal strip. The computer determines the temperatures occurring along a respective rotation part of the respective surface elements of the rotary elements and a rotary element shape which forms in the region of a draw-off point on the respective surface element, by a respective rotary element model and using an exchanged enthalpy quantity, the respective contact time with a metal and a respective cycle time exchanged per time unit of a respective rotary element of a casting device with the environment thereof. The temperature of the metal situated in the die region, and the heat flow from the metal to the respective surface element, are determined by a respective metallurgical solidification model and using a metal temperature, the temperatures of the surface elements, the rotary element shape and characteristic metal values.

An arrangement for controlling flow speed in a mold for continuous casting of metal includes: at least two first front cores with associated first magnetic coils arranged on one side of the mold; at least two second front cores with associated second magnetic coils arranged on an opposite side of the mold in substantial alignment with the first front cores; an external magnetic loop connecting the second front cores to the first front cores, to allow a one-directional magnetic flux to pass through the mold from the first front cores to the second front cores or vice versa; and a control interface enabling independent control of two subsets of the first magnetic coils.

A control method for a continuous casting machine, includes: estimating, by on-line real-time system, a flow state of molten steel in a mold by using an operation condition of a continuous casting machine and temperature data on the molten steel in the mold; calculating, by on-line real-time system, a molten steel flow index based on the estimated flow state of the molten steel, the molten steel flow index being a factor of mixing of an impurity into a casting inside the mold; and controlling the operation condition of the continuous casting machine such that the calculated molten steel flow index is within an appropriate range.