JP2002096147A - Sensing method and device for solidified shell thickness, molten steel flow rate and steel quality in entire area inside continuous casting mold - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an estimation method in time series for distribution of a molten steel flow and solidified shell thickness in the entire area inside a mold of a continuous casting machine. SOLUTION: Taking data in time series from thermometers attached to the mold, the molten steel flow rate around 2 or more temperature measuring points is calculated at each measuring time. Then vortex to cause the flow rate at each measuring point is figured out, from which distribution of a flow rate vector in the entire area inside the mold caused by the vortex is calculated. Based on the flow rate vector distribution, the solidified shell thickness distribution in the entire area inside the mold is estimated. The solidified shell thickness sensing method for the entire area inside the mold is in particular featured by the above procedure. The steel quality on-line visual sensing method and its device are also featured by visual display for calculation results of distribution of dispersed blowholes and/or inclusions based on the flow rate vector distribution in the entire area inside the mold.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an on-line visualization sensing method and apparatus for the thickness and quality of a fluidized solidified shell in a continuous casting facility, and more particularly, to a method for determining the quality of a slab. The present invention relates to a method for sensing a thickness of a solidified shell, a method for sensing online visualization of a thickness of a flow solidified shell, and an apparatus therefor.

[0002]

2. Description of the Related Art Conventionally, a shell thickness measuring method in continuous casting has been proposed. Japanese Patent Application Laid-Open No. 63-30162 (hereinafter referred to as "prior art 1") discloses a technique for measuring a shell thickness in continuous casting. An invention that predicts the occurrence of a breakout when the transition pattern matches a preset pattern is disclosed. Japanese Patent Application Laid-Open No. 1-262050 (hereinafter referred to as “prior art 2”) discloses detection of a drift of molten steel. In order to perform the method, there is disclosed an invention in which the drift of molten steel is detected based on a temperature difference or a heat flow difference and a deviation between left and right symmetric positions of a long side and a short side of a mold. FIG. 2 is a diagram of a conventional method for measuring a shell thickness in continuous casting. FIG. 3 is a diagram of a mold temperature measuring method in a continuous casting mold. 3A is a longitudinal sectional view of the continuous casting, taken along the line BB in FIG. 3B, and FIG. 3B is a transverse sectional view of the continuous casting, taken along the line AA in FIG. 3A. is there.

[0003]

When performing continuous casting in a mold in a continuous casting facility, molten steel 2 is supplied from an immersion nozzle 4 to the continuous casting mold 1, and the molten steel 2 is made of copper with a cooling box 7 installed on the back. Is removed from the surface of the continuous casting mold 1 and solidified to form a solidified shell 3. The solidified shell 3 is pulled out from below the continuous casting mold 1 by the roll 6. The distribution of the thickness, the distribution of inclusions, and the distribution of bubbles of the solidified shell 3 affect the quality of the cast slab.
For this reason, conventionally, in order to monitor the quality of the slab, a technology for installing a thermocouple 5 inside the cooling copper plate of the mold 1 and monitoring the temperature in time series has been developed. However, the drift detection method disclosed in Prior Art 2 could not detect the flow velocity distribution. Further, in the method of measuring the shell thickness in the continuous casting disclosed in the prior art 1 shown in FIG. 2, this temperature monitor is possible only at the thermocouple installation position, and in that the thermocouple is not installed. Was difficult to monitor.

That is, in the conventional flow sensing method, when the casting direction is the X direction and the direction perpendicular to the casting is the Y direction, the position (Xi, Yi) of the thermocouple 5 and the temperature Ti at that point are calculated as follows. The absolute value (scalar value) | U | of the flow velocity U was obtained from the equation (1).

(Equation 1)

More specifically, as can be easily obtained from the description of Itsuo Ohnaka, "Introduction to Computerized Heat Transfer and Solidification Analysis" (Maruzen 1985), pp. 336-337, the thermocouple temperature Ti
(° C.), absolute value of flow rate | U (Xi, Yi) | (meters per second), heat transfer coefficient h (watts per square meter per Kelvin), cooling water temperature Tw (° C.), heat removal q (watts per square meter), Representative length d (meter), kinematic viscosity coefficient ν
(Square meter per second), thermal conductivity λ (watts per meter per kelvin), Nusselt number Nu [−], Reynolds number Re [−], and prandle number Pr [−] have the following formula (2): Equation (1) is obtained by equation transformation.

(Equation 2)

In the conventional method using these equations, the absolute value of the flow velocity U cannot be obtained except at the thermocouple installation position 5, and the flow velocity vector indicating the direction of the flow velocity cannot be obtained even at the thermocouple installation position 5. . In addition, there is a problem that increasing the number of measurement points is costly and has an effect on uniform cooling, so that it is difficult to improve the accuracy. The present invention
In view of the above problems, in a continuous casting facility, inexpensive, a method capable of estimating the solidified shell thickness distribution and the diffusion distribution of bubbles and inclusions throughout the mold by using an existing thermocouple so as not to adversely affect uniform cooling and It is intended to provide a device.

[0007]

SUMMARY OF THE INVENTION The present inventor has proposed a method for estimating shell thickness and bubbles / inclusions in a continuous casting facility, which can estimate the time-series flow distribution over the entire area of a mold by using an inexpensive apparatus that does not adversely affect uniform cooling. As a result of intensive investigations, using time-series data obtained from temperature measuring instruments installed in the mold, the molten steel flow velocity near two or more temperature measuring instrument installation points was calculated at each measurement time, and then each The vortex that generates the flow velocity at each measurement point is determined, and then the flow velocity vector distribution that the vortex forms throughout the mold is calculated, and the solidified shell thickness distribution and air bubbles / air bubbles throughout the mold are calculated using the flow velocity vector distribution. It has been found that by estimating the inclusion distribution, it is possible to estimate the time-series flow distribution of the entire region in the mold at low cost without adversely affecting uniform cooling.

The present invention has been made on the basis of the above findings, and the gist of the invention is as follows: (1) Time series obtained from two or more temperature measuring instruments installed on a long side in a continuous casting mold. Using the data, calculate the flow velocity of the molten steel near the temperature measuring instrument installation point at each measurement time, then find the vortex that causes each flow velocity at each measurement point, and then form the vortex throughout the mold A method of calculating a flow velocity vector distribution and estimating a solidified shell thickness distribution throughout the continuous casting mold using the flow velocity vector distribution; and (2) using two or more temperature measuring instruments installed on a short side in the continuous casting mold. Using the obtained time-series data, calculate the molten steel flow velocity near the temperature measuring instrument installation point at each measurement time, then find the vortex that generates the relevant flow velocity at each measurement point, and then use that vortex as the mold Calculate the flow velocity vector distribution formed in the whole area How to estimate the solidified shell thickness distribution of the continuous casting mold in the entire region using a fast vector distribution also,
(3) Using time-series data obtained from two or more temperature measuring instruments installed on the long side in the continuous casting mold, calculate the molten steel flow velocity near the temperature measuring instrument installation point at each measurement time, and then perform each measurement The vortex that generates each of the flow rates at the point is determined, and then the flow velocity vector distribution formed by the vortex in the entire area within the mold is calculated.Using the flow velocity vector distribution, the molten steel discharge velocity from the immersion nozzle at each measurement time is calculated. And then estimating the descending flow velocity of the molten steel in the mold, a method for sensing the flow velocity of the molten steel in the entire continuous casting mold, and (4) the above (1) to (4).
(3) A method of calculating and visualizing the diffusion distribution of bubbles and / or inclusions using the flow velocity vector distribution in the entire mold obtained by the method according to any one of (3), (5) Continuous casting mold Two or more temperature measuring instruments installed in the inside, molten steel flow velocity calculating means for calculating the molten steel flow velocity near the temperature measuring instrument installation point using time-series data obtained from the temperature measuring instrument, and at each temperature measuring point Vortex calculating means for calculating a vortex that generates the molten steel flow velocity, flow velocity vector calculating means for calculating a flow velocity vector distribution formed by the vortex throughout the mold, and a solidified shell thickness distribution throughout the mold from the flow velocity vector distribution. A solidified shell thickness sensing device, comprising: a calculated solidified shell thickness calculating means; and an output means. (6) In addition to the temperature measuring device, the molten steel flow velocity computing means, the vortex computing means, the flow velocity vector computing means, and the output means according to the above (5), bubble interposition for calculating the diffusion distribution of bubbles and / or inclusions from the flow velocity vector distribution. A slab quality on-line visualization sensing device comprising material diffusion calculation means. (7) two or more temperature measuring instruments installed in the continuous casting mold, and molten steel flow velocity calculating means for calculating the molten steel flow velocity near the temperature measuring instrument installation point using time-series data obtained from the temperature measuring instruments; Vortex calculating means for calculating a vortex that generates the molten steel flow velocity at each temperature measurement point, flow velocity vector calculating means for calculating a flow velocity vector distribution formed by the vortex in the entire region of the mold, and a molten steel mold from the flow velocity vector distribution. A molten steel flow velocity sensing device comprising: a downward flow velocity calculating means for estimating an inward downward flow velocity; and an output means. It is in.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, in the invention according to the above (1), each measurement time is measured by using time series data obtained from two or more temperature measuring instruments installed on a long side in a mold in a continuous casting facility. Calculate the molten steel flow velocity near two or more temperature measuring instrument installation points, then find the vortex that generates each flow velocity at each measurement point, and then calculate the flow velocity vector distribution that the vortex forms throughout the mold. The calculation method will be described with reference to the drawings.
FIG. 1 is a flowchart of the method for sensing the thickness of a solidified shell in the entire region of a mold according to the present invention. FIG. 4 is an explanatory diagram of the method for sensing the thickness of the solidified shell over the entire area of the mold when a thermocouple is installed on the long side of the mold according to the present invention. In the present invention, i is a thermocouple number, the vortex model 9 having a radius R (meter) and a vorticity Ω (/ sec) is considered to be at the vortex center (Xv, Yv), and the thermocouple 5 of the vortex model 9 is considered. By making the absolute value of the flow velocity vector 10 induced at the installation position (Xi, Yi) equal to the converted flow velocity absolute value (scalar value) 8 from the thermocouple,
The vortex model 9 identifies the vortex center (Xv, Yv), and the obtained vortex model 9 can determine flow velocity vectors induced at all points in the mold 1.

[0010] Specifically, the installation position of each thermocouple 5 (X
The absolute value of the flow velocity U (meters / second) of (i, Yi) is expressed by Expression (1) as a function of the temperature Ti at each point. FIG.
(A) is an image of this distribution. FIG.
As shown in (a), in the conventional method, the flow velocity distribution is not displayed except at the installation position 5 of the thermocouple. Alternatively, the shell thickness distribution at each point is calculated from the thermocouple data according to FIG. 2, but also at this time, only the data of the thermocouple installation position alone is obtained. In the present invention, the vortex model 9 having a radius R (meters) and a vorticity Ω (/ sec) has a vortex center (Xv, Y
v), and the flow velocity vector 10 induced at the installation position (Xi, Yi) of the thermocouple 5 of the vortex model 9, that is, U
(Xi, Yi) = (ui, vi) is represented by the following equation (3).

(Equation 3) Specifically, using the equation described in Japanese Patent Application Laid-Open No. 7-323356, the following equation (4) is obtained by summing the sum of the numbers j of the mirror images of the vortex.
Equation (3) is obtained by rearranging

(Equation 4) In equation (4), j is the number of the mirror image of the vortex when the wall and the meniscus are symmetric axes, J = 1 is a real image, J = 2 to 4 are mirror images, and (X _vj , Y _vj ) is the j-th. Center coordinates (± X
v, ± Yv). The angle formed by the vector from the center of each vortex to the point for obtaining the flow velocity with the y-axis was θ _j , and the absolute value of the vector was r _j . Here, if the absolute value of the flow velocity U and the components ui and vi of the flow velocity vector 10 satisfy the following equation (5), the thermocouples 5 for the variables Xv, Yv, R, and Ω
One equation is established for the installation position (Xi, Yi) of the thermocouple 5. In principle, the installation position (Xi, Yi) of the thermocouple 5 is set to 4
By taking points, variables Xv, Yv, R, and Ω are obtained.

(Equation 5) Thereby, the vortex center (Xv, Yv) of the vortex model 9 can be identified.

Next, a flow velocity vector (u, v) induced at an arbitrary point (x, y) in the mold 1 by the obtained vortex model 9
Can be obtained by the following equation (6) using the equation (4).

(Equation 6) In this method, R and Ω may be separately obtained from geometrical assumptions in the mold. In this case, the installation positions (Xi, Yi) of the thermocouple 5 can be two. Thermocouple 5
When the installation position (Xi, Yi) is 5 or more, the vortex center (Xv, Yv) of the vortex model 9 is identified by solving the equation (3) at each point so that the error is minimized. Can be.

Next, in the invention according to the above (2), two points are measured at each measurement time using time-series data obtained from two or more temperature measuring instruments installed on the short side of the mold in the continuous casting facility. Calculate the molten steel flow velocity near the above temperature measuring instrument installation point,
Next, a method of obtaining a vortex that generates each flow velocity at each measurement point, and then calculating a flow velocity vector distribution formed by the vortex in the entire region in the mold will be described with reference to the drawings. FIG. 8 is an explanatory diagram of the method for sensing the thickness of the solidified shell over the entire area of the mold when a thermocouple is installed on the short side of the mold according to the present invention.

In the present invention, i is a thermocouple number,
When the vortex model 9 having a radius R (meters) and a vorticity Ω (/ sec) is considered to be at the center of the vortex (Xv, Yv), the width of the long side of the mold is set to W, and the origin of the coordinates is set at the center of the meniscus. The absolute value of the flow velocity vector 10 induced at the installation position (Xi, ± W / 2) of the thermocouple 5 of the vortex model 9 is made equal to the converted flow velocity absolute value (scalar value) 8 from the thermocouple. Then, the vortex model 9 identifies the vortex center (Xv, Yv),
The flow velocity vectors induced at all points in the mold 1 by the obtained vortex model 9 can be obtained. Specifically, the absolute value of the flow velocity U (meter / second) at the installation position (Xi, ± W / 2) of each thermocouple 5 is expressed by the equation (1) as a function of the temperature Ti at each point. In the conventional method, the flow velocity distribution is not displayed except at the installation position 5 of the thermocouple. Alternatively, the shell thickness distribution at each point is calculated from the thermocouple data according to FIG. 2, but also at this time, only the data of the thermocouple installation position alone is obtained. Alternatively, when a thermocouple was installed only on the short side, the flow velocity distribution on the long side could not be estimated. In the present invention, it is considered that the vortex model 9 having a radius R (meter) and vorticity Ω (/ sec) is located at the vortex center (X0, Y0), and the installation position (Xi, ±) of the thermocouple 5 of the vortex model 9 is considered. W / 2) induced flow velocity vector 10, ie, U (xi, ± W / 2) =
(Ui, vi) is expressed by the coordinates (xi, ± W / 2) in equation (4).
Is expressed by the following equation (12).

(Equation 12) Since this equation uses the vortex angular velocity Ω, the vortex radius R, and the vortex center coordinate components x0 and y0 as variables, a thermocouple is placed on one side of the short side.
It can be obtained by setting the number of points or more, formulating equation (12) for each of them, and simultaneously solving simultaneous equations. Next, the flow velocity vector (u, v) induced at the arbitrary point (x, y) in the mold 1 by the obtained vortex model 9 can be obtained by Expression (6) using Expression (4). .

Using the flow velocity vector distribution in the whole area of the mold obtained by any of the above methods, the molten steel discharge velocity from the immersion nozzle is calculated at each measurement time, and then the descending velocity of the molten steel in the mold is estimated. The method according to the invention (3) will be described with reference to FIG. By the above method, the flow velocity vector distribution above the molten steel discharge flow 11 from the immersion nozzle can be predicted, and the flow velocity U0 of the molten steel discharge flow 11 from the immersion nozzle and the flow velocity Ujet downstream thereof can be experimentally induced. It can be estimated using the following relational expression (13).

(Equation 13) Here, L is the distance (meter) along the discharge flow from the discharge hole, Ujet (L) is the absolute value of the flow velocity at the distance L (meters per second), U0 is the discharge flow velocity (meters per second), and d0 is the diameter of the nozzle (Meters), C1 and k, k2, k3, L0
Is a constant obtained experimentally (C1 = 6.0, k = −
1.0, k2 = 1.0, k3 = 1.0, L0 = 5 × d
0). The flow velocity Udown of the downflow 12 in the mold of molten steel
(Meters per second) can be estimated using the experimental relational expression (14).

(Equation 14) Here, L is the distance (meter) along the discharge flow from the discharge hole, Udown is the absolute value of the flow velocity (meter per second), and C2, m, and L1 are constants obtained experimentally (C2 = 5.
0, m = -0.5, L1 = 5 * d0). Further, the flow velocity distribution u (r) perpendicular to the discharge flow is expressed by Expression (15) using the half-value width b (L) at a position at a distance L (meter) from the discharge hole.

(Equation 15) In the range from the ejection hole to the collision with the wall surface, ujet obtained by Expression 13 is substituted into Expression 16 to obtain u (r).

(Equation 16) In the range after the collision with the wall surface, u (r) is obtained by substituting Udown obtained by Expression 14 into Expression 17.

(Equation 17) Here, r is a vertical distance (meter) from a position having a distance L along the discharge flow center from the discharge hole, u (r) is an absolute value of flow velocity (meters per second), and C3, C4, and C5 are experimentally These are the obtained constants (C3 = 0.05, C4 = 0.
7, C5 = 0.7).

From the above, it is possible to predict the flow velocity distribution not only in the mold but also in the whole area below the mold. That is, with respect to an arbitrary point (x, y) at the lower portion of the mold, there is a distance L from the discharge hole along the center of the discharge flow and a distance r from the position L in the vertical direction r, and , R can be uniquely determined so that L and r are minimized. From the obtained L, r, and Ω and R used to calculate the vortex, U0, Ujet, Ud
seek own, and finally any point (x,
The flow velocity u (r) at y) is obtained, and the flow velocity vector can be obtained by setting the unit vector of u (r) along the line of the distance L along the center of the discharge flow. After further obtaining the descending flow velocity, the flow velocity u (r) at an arbitrary point (x, y) at the lower part of the mold is substituted into the expression of the shell thickness distribution and the inclusion distribution.
Next, the paper “Yamada, Y. and Suzuki, N .: Numerical Simulation
and Visualization for Fluid Motion with Solidific
ation in Continuous Casting, WCCM-III, Makuhari, p
p. 1772-1773 (1994) "and the 6th Computational Mechanics Conference of the Japan Society of Mechanical Engineers," Yamada and Suzuki, "Simulation of Flow Solidification in Continuous Casting" pp. 360-361 (199
3) As described in "), by integrating the solidification growth rate which is a function of the absolute value of the flow velocity at each point from the meniscus which is the solidification start point, the invention according to the above (1) or (2) is achieved. The solidified shell thickness distribution throughout the mold can be calculated.

Specifically, at any point (x, y), the shell thickness heat dissipation q (watt / square meter), the molten metal temperature T∞ (° C.), the solidification temperature Tm (° C.) of the molten metal, Density ρ (kilogram / cubic meter), latent heat L of molten metal (joule / kilogram), solidification speed V (meter / second), casting speed Vc (meter / second), calculation interval Δx (meter) in casting direction, solidification start point The following equation (7) holds for the sum Σ (−) in the direction of the casting distance from. The heat removal amount q and the heat transfer coefficient h are estimated from the flow velocity at an arbitrary point (x, y) using the equation (2), and the solidification speed V
(M / s) is calculated, and the shell thickness distribution δ (x, y) at an arbitrary point (x, y) can be calculated.

Equation 7 In addition, since the flow velocity distribution in the entire region is given, inclusion advection can be estimated by Lagrangian integration of the position of the inclusion. Specifically, the inclusion velocity Vp (t) at time t is obtained by the following equation (8) obtained by modifying the equation described in “Mechanism of Multiphase Fluid” (Asakura Shoten 1991), p. M / sec), resistance coefficient Cd (= 24 / Re + 6 / (1 + √Re) +0.4)
Re is Reynolds number), relative velocity with fluid (u-Vp)
(T)) (meter / second), acceleration g (meter / square second) due to external force, and movement Xp (t) (meter) of the inclusion can be obtained with respect to time step Δt (second).
The movement Xp (t) of the bubble can be obtained by time integration of the inclusion velocity Vp (t) (meter / second).

(Equation 8)

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS.
An embodiment of the present invention will be specifically described. FIG. 5 is a molten steel flow velocity vector diagram estimated using the method for sensing the thickness of the solidified shell in the entire region of the mold according to the present invention. In a mold 1 having an inner width (long side) of 1 m, a thickness (short side) of 30 cm, and a distance from the meniscus to the lower end of the mold (depth) of 60 cm in a continuous casting facility, molten steel 2 is continuously cast from an immersion nozzle 4 having a diameter of 20 cm and 2 holes. It is supplied to the mold 1 and continuous casting is performed. The molten steel 2 is removed from the surface of the continuous casting mold 1 and solidifies to form a solidified shell 3. The solidified shell 3 is drawn from below the continuous casting mold 1 by a roll 6 at a drawing speed of 1 m / min. The distribution of the thickness, the distribution of inclusions, and the distribution of bubbles of the solidified shell 3 affect the quality of the cast slab. For this reason, conventionally, to monitor slab quality,
A thermocouple 5 is placed 5 cm from the casting surface inside the cooling copper plate of the mold 1.
At a depth of 10 cm and 30 cm from both ends and 10 cm and 30 cm from the upper end, respectively, and eight pieces were installed on each side, and the temperature was monitored in time series.

In the present invention, the radius R (meter),
It is assumed that the vortex model 9 having a vorticity of Ω (/ sec) is at the vortex center (Xv, Yv). Assuming that the installation numbers i of the thermocouples 5 are i = 1 to 4, the installation positions of the four points on the left side are determined as in the following equation (9).

[Equation 9] According to the procedure of the embodiment of the invention, the following equation (10) is obtained for i = 1 to 4.

(Equation 10) By transforming equation (10), the following equation (11) is obtained.

[Equation 11] The variables Xv, Yv, R, and Ω are calculated using the four equations of Expression (11).
Is determined, and the vortex center (Xv, Yv) of the vortex model 9 is identified.

Next, a flow velocity vector (u, v) induced at an arbitrary point (x, y) in the mold 1 by the obtained vortex model 9
Can be obtained by Expression (6). FIG. 5 shows a flow velocity vector molten steel flow velocity vector diagram obtained by this solution. The distance from the meniscus to the upper end of the discharge port of the immersion nozzle was 0.2 m. Next, the distribution of solidified shell thickness and inclusion advection throughout the mold were estimated by Lagrangian integration using the flow velocity vector distribution throughout the mold. FIG. 6 shows the thickness distribution of the solidified shell, and FIG. 7 shows the distribution of inclusions. In FIG. 6, the thickness of the solidified shell is shown by contour lines in millimeters. The values almost 10 mm were obtained near the position of the discharge port of the immersion nozzle and 14 mm at a depth of 0.4 m from the meniscus.

In FIG. 7, the inclusion distribution when the display range is the same as that in FIG. 6 (inclusion distribution is a relative number density ratio [−] when inclusions are given uniformly as inflow conditions) In Fig. 9, a portion where the number density is the largest is indicated by contour lines in increments of 0.2, and Fig. 9 shows an example of a prediction calculation of a flow velocity vector in the entire mold up to the lower portion of the mold. 9 (a) shows the flow velocity distribution at the center cross section of the short side of the mold, and FIG.9 (b) shows the flow velocity distribution at the solidified surface of the long side of the mold. Since a typical flow velocity distribution is obtained, the three-dimensional behavior of a wide range of inclusions and bubbles can be calculated.

[0021]

According to the present invention, two or more temperature measuring instrument installation points are used at each measurement time using time series data obtained from the temperature measuring instruments installed on the long side or the short side in the continuous casting mold. The flow velocity of the molten steel is calculated, then the vortex that generates the flow velocity at each measurement point is determined, and then the flow velocity vector distribution that the vortex forms throughout the mold is calculated. The solidification shell thickness and the distribution of inclusions or bubbles can be determined.

[Brief description of the drawings]

FIG. 1 is a flowchart illustrating a method for sensing the thickness of a solidified shell in the entire region of a mold according to the present invention.

FIG. 2 is a flowchart illustrating a conventional method for sensing a solidified shell thickness.

3A and 3B are explanatory diagrams of a method of measuring a mold temperature in a continuous casting mold. FIG.
(B) is a cross section taken along the line BB, and (b) is a cross section of a long side of the continuous casting mold (a cross section taken along the line AA in FIG. 3 (a)).

FIG. 4A is an explanatory diagram of a conventional method of calculating a flow velocity distribution at a thermocouple installation position. (B) It is explanatory drawing of the flow velocity vector distribution calculation method in the whole area | region in a casting_mold | template in case a thermocouple is installed in the long side of a casting_mold | template of this invention.

FIG. 5 is a molten steel flow velocity vector diagram estimated using the method for sensing the thickness of a solidified shell in the entire region of a mold according to the present invention.

FIG. 6 is an example of estimating a solidified shell thickness distribution according to the present invention.

FIG. 7 is an example of estimation of inclusion distribution according to the present invention.

FIG. 8 is an explanatory diagram of a method of calculating a flow velocity vector distribution over the entire region in a mold when a thermocouple is installed on the short side of the mold according to the present invention.

FIG. 9 (a) is an example showing the flow velocity distribution in the center cross section of the short side of the mold of the present invention. (B) Example of the present invention showing the flow velocity distribution on the solidification surface of the long side of the mold.

[Brief description of reference numerals]

 DESCRIPTION OF SYMBOLS 1 Continuous casting mold 2 Molten steel 3 Solidification shell 4 Immersion nozzle 5 Thermocouple 6 Drawing roll 7 Cooling box 8 Converted absolute value of flow velocity from thermocouple (scalar value) 9 Vortex model 10 Induced velocity vector of vortex model 11 Molten steel from immersion nozzle Discharge flow 12 Downflow of molten steel in mold

Claims (7)

[Claims] (1) using time-series data obtained from two or more temperature measuring instruments installed on a long side in a continuous casting mold, calculating a molten steel flow velocity near a temperature measuring instrument installation point at each measurement time; Find the vortex that generates each flow velocity at each measurement point, then calculate the flow velocity vector distribution that the vortex forms throughout the mold,
A method for sensing a thickness of a solidified shell in the entire continuous casting mold, comprising estimating a solidified shell thickness distribution in the entire casting mold using the flow velocity vector distribution. 2. Using the time series data obtained from two or more temperature measuring instruments installed on the short side in the continuous casting mold, calculate the molten steel flow velocity near the temperature measuring instrument installation point at each measurement time, Find the vortex that generates each flow velocity at each measurement point, then calculate the flow velocity vector distribution that the vortex forms throughout the mold,
A method for sensing a thickness of a solidified shell in the entire continuous casting mold, comprising estimating a solidified shell thickness distribution in the entire casting mold using the flow velocity vector distribution. 3. Using a time series data obtained from two or more temperature measuring instruments installed in a continuous casting mold, calculate a molten steel flow velocity near a temperature measuring instrument installation point at each measurement time, and then calculate each measurement time. The vortex that generates the flow velocity at the point is determined, and then the flow velocity vector distribution formed by the vortex in the entire area within the mold is calculated.Using the flow velocity vector distribution, the molten steel discharge velocity from the immersion nozzle at each measurement time is calculated. , And then estimating the descending flow velocity of the molten steel in the mold. 4. A method for calculating a diffusion distribution of bubbles and / or inclusions using a flow velocity vector distribution in the entire region of a mold obtained by the method according to any one of claims 1 to 3, and displaying the calculated distribution. A method for online visualization sensing of slab quality throughout the continuous mold. 5. A molten steel flow rate calculating means for calculating a molten steel flow rate near a temperature measuring instrument installation point using two or more temperature measuring instruments installed in a continuous casting mold and time series data obtained from the temperature measuring instruments. Vortex calculating means for calculating a vortex that generates the molten steel flow velocity at each temperature measurement point; flow velocity vector calculating means for calculating a flow velocity vector distribution formed by the vortex in the entire region of the mold; and a mold from the flow velocity vector distribution. A solidified shell thickness sensing device, comprising: a solidified shell thickness calculating means for calculating a solidified shell thickness distribution over the entire area; and an output means. 6. A bubble for calculating a diffusion distribution of bubbles and / or inclusions from a flow velocity vector distribution, in addition to the temperature measuring device, molten steel flow velocity calculation means, vortex calculation means, flow velocity vector calculation means and output means according to claim 5. A slab quality on-line visualization sensing device comprising inclusion diffusion calculation means. 7. A molten steel flow velocity calculating means for calculating a molten steel flow velocity near a temperature measuring instrument installation point using two or more temperature measuring instruments installed in a continuous casting mold and time-series data obtained from the temperature measuring instruments. Vortex calculation means for calculating a vortex that generates the molten steel flow velocity at each temperature measurement point; flow velocity vector calculation means for calculating a flow velocity vector distribution formed by the vortex in the entire area of the mold; and molten steel from the flow velocity vector distribution. A flow velocity sensing device for molten steel, comprising: a downward flow velocity calculating means for estimating the downward flow velocity in the mold.