JP2001212653A - Liquid metal flow control apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid metal flow control apparatus which prevents liquid metal from staying and solidifying at three important points of a mold. SOLUTION: At four corners of the mold 13, linear motor coils 151-154 and liquid metal flow-speed detector 171-174 are installed. When liquid metal flow- speed decision devices 181-184 judge that liquid metal flow-speed is under a border level, determining that liquid metal is in risk of solidifying at four corners of the mold, liquid metal flow-speed decision devices 181-184 outputs signals for action to start electric resources 161-164 and energize linear motor coils, so that liquid metal at four corners acquires fluid power to restrain solidification, which prevents the inferiority of slab quality.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a molten metal flow control device, and more particularly to a molten metal flow control device applied to a rotary drum mold.

[0002]

2. Description of the Related Art In a continuous casting apparatus for manufacturing a slab from molten steel in a tundish, a reverse rotation is performed in a direction in which molten steel in a mold is mutually wound with a predetermined gap on the bottom surface.
A rotating drum mold in which two rotating drums are arranged may be used. FIG. 1 is a top view (A) and a cross-sectional view (XX) of a rotary drum mold, showing two rotary drums 11 and 12 arranged in parallel with a space d therebetween.
Rotate in opposite directions to each other to draw the molten steel in the mold.

A rectangular mold 13 for preventing molten steel from overflowing is installed on the two rotating drums 11 and 12, and the mold 13 is composed of two side weirs 131 and 13.
2 and two scum weirs 133 and 134. In addition, molten steel in a dandysh (not shown) is injected into the mold 13 through an immersion nozzle 14 arranged at the center of the mold.

The injected molten steel descends inside the nozzle 14 and collides with the bottom plate, flows out of the nozzle in the horizontal direction, collides with the scum weirs 133 and 134 and scums weirs 133 and 134
Flows along. And the molten steel in the mold 13 is 2
It is drawn in by the two rotating drums 11 and 12, and is drawn out downward. Since the rotating drum is cooled by an appropriate cooling device, it is solidified and formed into a slab shape.

[0005]

However, at the four corners of the mold 13 where the side weirs 131 and 132 and the scum weirs 133 and 134 intersect, the molten steel is liable to stagnate and solidify. Deterioration of quality cannot be avoided. The present invention has been made in view of the above problems, and has as its object to provide a molten metal flow control device that can prevent molten metal from stagnating and solidifying at a triple point of a mold.

[0006]

According to a first aspect of the present invention, there is provided a molten metal flow control device comprising: a rotating drum rotating in opposite directions to each other across a gap disposed on a bottom surface; Excitation power is applied to each of the scum weir and the mold composed of the side weir arranged at right angles to the rotation axis of the rotary drum, the linear motor coil arranged along the scum weir or the side weir, and the linear motor coil. And a power supply for supplying the power.

In the present invention, a flow force is applied to the molten metal by supplying electric power to the linear motor coil. A molten metal flow control device according to a second aspect of the present invention includes a rotating drum rotating in opposite directions to each other with a gap provided on a bottom surface, and a scum weir and a rotating drum arranged in parallel with a rotating shaft of the rotating drum. Exciting power is applied to each of the four linear motor coils, and a mold composed of side dams arranged at right angles to the rotation axis, four linear motor coils arranged at four corners of the mold along the scum dam or the side dam. And four power supply units for supplying.

In the present invention, a flow force is applied to the molten metal at the four corners of the mold by supplying electric power to the linear motor coil. A molten metal flow control device according to a third aspect of the present invention includes a rotating drum rotating in opposite directions to each other with a gap provided on a bottom surface, a scum weir and a rotating drum arranged in parallel with a rotating shaft of the rotating drum. Exciting power is applied to each of the four linear motor coils, and a mold composed of side dams arranged at right angles to the rotation axis, four linear motor coils arranged at four corners of the mold along the scum dam or the side dam. Four power supply devices to be supplied, four flow rate detectors arranged at the four corners of the mold to detect the flow rate of the molten metal injected into the mold, and the flow rates of the molten metal detected by the four flow rate detectors are predetermined. And four flow rate judging devices for outputting an operation command to the corresponding one of the four power supply devices when the threshold value is equal to or less than the set threshold value.

According to the present invention, when it is detected that the flow velocity of the molten metal at the corner of the mold has become smaller than the threshold value, electric power is supplied to the linear motor coil to apply a flowing force to the molten metal. According to a fourth aspect of the present invention, there is provided a flow controller for molten metal, wherein each of the four flow rate detectors captures an image of the molten metal at the four corners of the mold, and a self-image of the molten metal captured by the imaging device. An autocorrelation function operation unit that calculates a correlation function every predetermined time, and a flow velocity determination unit that determines the flow velocity of the molten metal based on the moving distance of the pattern calculated by the autocorrelation function operation unit Is done.

In the present invention, the flow rate of the molten metal is determined by processing images of the molten metal at the four corners of the mold. A molten metal flow control device according to a fifth aspect of the present invention includes a molten metal temperature detector that detects the temperature of the molten metal based on the amount of infrared radiation emitted by the molten metal at the four corners of the mold. A flow rate determining unit that determines the flow rate of the molten metal based on the temperature of the molten metal detected by the molten metal temperature detector.

In the present invention, the flow rate of the molten metal is determined based on the temperatures of the molten metal at the four corners of the mold. According to a sixth aspect of the present invention, there is provided a molten metal flow control device, wherein each of the four flow velocity detecting devices is a flow force detecting member inserted into the molten metal at the four corners of the mold, and a flow of the molten metal received by the flow force detecting member. It is composed of a fluid force detecting unit that detects a force, and a flow velocity determining unit that determines the flow velocity of the molten metal based on the flowing force of the molten metal detected by the fluid force detecting unit.

In the present invention, the flow velocity of the molten metal is determined based on the force received by the flow force detecting member inserted into the molten metal at the four corners of the mold.

[0013]

FIG. 2 is a block diagram of a molten metal flow control device according to the present invention, and FIGS. 3 and 4 are front and sectional views of a mold provided with a molten metal flow control device according to the present invention. It is. That is, at the four corners of the mold 13, linear motor coils 151 to 154 and linear motor coils 151 for applying fluid force to the molten steel along the scum weirs 131 and 132 are provided.
Power supplies 161 to 16 for supplying AC power to
4. Molten steel flow velocity detecting devices 171 to 174 for detecting the flow velocity of the molten steel at the four corners of the mold 13, and determining whether or not the flow velocity of the molten steel is equal to or less than a predetermined threshold value. Are provided with molten steel flow velocity judging devices 181 to 184 which output operation commands. The molten steel is injected from an immersion nozzle 14 arranged at the center of the mold 13.

Four linear motor coils 151 to 154
Has the same structure. For example, at least six divided coils 15b to 15g are wound around a comb-shaped iron core 15a arranged along the scum weir 131 or 132. FIG.
FIG. 5 is a connection diagram between two linear motor coils 15 and a power supply device 16, in which a winding end terminal (●) of a coil 15 b is in a U phase of the power supply device, a winding start terminal (○) of a coil 15 c is in a V phase of the power supply device, The winding end terminal (●) of the coil 15d is connected to the W phase of the power supply.

A winding start terminal (○) of the coil 15b
Indicates a winding start terminal (○) of the coil 15e and the coil 15c
Is the winding end terminal (●) of the coil 15f and the winding start terminal (ｆ) of the coil 15d.
Is connected to the winding start terminal (○) of the coil 15g. Further, the winding end terminal (●) of the coil 15e, the coil 1
The winding start terminal (○) of 5f and the winding end terminal (●) of the coil 15g are commonly connected.

The four power supplies 161 to 164 have the same configuration, and convert a three-phase AC supplied from a three-phase AC power supply 19 into DC, a converter 16a, and a converter 1
Voltage control section 16 for controlling the DC voltage output from 6a
b, a converter 16c for reconverting DC to three-phase AC, and a frequency controller 16d for three-phase AC output from the converter 16c.

When electric power is supplied from the power supply to the linear coil, a moving magnetic field is generated along the scum weir 131 or 132 to apply fluidity to molten steel in the mold. The four molten steel flow velocity detecting devices 171 to 174 have the same configuration, and are configured by, for example, a CCD camera. CC
As a method for detecting the flow velocity of the molten steel based on the image of the molten steel taken by the D camera, a known method can be applied. For example, an autocorrelation function of the image is calculated at regular time intervals to calculate the autocorrelation pattern. It is possible to determine the flow velocity of the molten steel from the moving distance of the steel.

Further, as another configuration of the molten steel flow velocity detecting device, it is possible to apply a method of detecting a force received by a molybdenum steel rod inserted into molten steel by a strain gauge.
Further, the four molten steel flow velocity determination devices 181 to 184 have the same configuration, and determine whether the flow velocity of the molten steel detected by the molten steel flow velocity detection device is equal to or less than a predetermined threshold. At some point, an operation command is output to the power supply assuming that the molten steel has started to solidify.

When any one of the molten steel flow velocity determining devices 181 to 184 outputs an operation command, the corresponding power supply device 171 to 184 is output.
174 supplies electric power to the linear motor coils 151 to 154, and applies fluidity to the molten steel at the triple point which is about to solidify to prevent further solidification. 6 and 7 are explanatory diagrams (1/2) and (2/2) of the effect of the present invention. FIG.
(A) is a flow pattern when the linear motor coil is not provided, and (B) is a flow pattern when the linear motor coil is provided. When the linear motor coil is not provided, the molten steel hardly flows in the corner. On the other hand, when the linear motor coil is provided, it can be seen that the molten steel flows even in the corners.

The horizontal axis of FIG. 7 represents the distance from the mold center along the scum weir, and the vertical axis represents the flow rate of molten steel along the scum weir. The solid line shows the case without the linear motor coil, and the broken line shows the case with the linear motor coil. From this graph, it was found that the linear motor coil was used for approx.
It can be seen that a flow rate of 1 m / s is provided.

In the above embodiment, the linear motor coil is arranged along the scum weir, but the same effect can be obtained even if it is arranged along the side weir.

[0022]

According to the molten metal flow control device of the present invention, when the flow velocity of the molten metal at the four corners of the mold becomes less than the threshold value, the linear motor coil is excited to promote the flow of the molten metal. This makes it possible to suppress slab quality deterioration caused by solidification of the molten metal.

[Brief description of the drawings]

FIG. 1 is a top view and a sectional view of a rotary drum mold.

FIG. 2 is a configuration diagram of a molten metal flow control device according to the present invention.

FIG. 3 is a front view of a mold provided with the molten metal flow control device according to the present invention.

FIG. 4 is a cross-sectional view of a mold provided with the molten metal flow control device according to the present invention.

FIG. 5 is a connection diagram of a linear motor coil and a power supply device.

FIG. 6 is an explanatory diagram (1/2) of an effect of the present invention.

FIG. 7 is an explanatory diagram (2/2) of the effect of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 13 ... Mould 131,132 ... Scum weir 133,134 ... Side weir 151-154 ... Linear motor coil 161-164 ... Power supply device 171-174 ... Molten steel flow velocity detecting device 181-184 ... Molten steel flow velocity judging device

Claims (6)

[Claims] 1. A rotating drum that rotates in opposite directions to each other across a gap disposed on a bottom surface, a scum weir arranged in parallel with a rotating shaft of the rotating drum, and a scum dam perpendicular to the rotating shaft of the rotating drum. A mold comprising a side weir arranged; a linear motor coil arranged along the scum weir or the side weir; and a power supply unit for supplying excitation power to each of the linear motor coils. Metal flow control device. 2. A rotating drum rotating in opposite directions to each other with a gap disposed on a bottom surface, a scum weir arranged in parallel with a rotating shaft of the rotating drum, and a scum dam perpendicular to the rotating shaft of the rotating drum. A mold composed of side dams arranged; four linear motor coils arranged along the scum dam or the side dams at four corners of the mold; and an excitation power supply to each of the four linear motor coils. And a power supply device for controlling the flow of molten metal. 3. A rotating drum rotating in opposite directions to each other with a gap therebetween, a scum weir arranged in parallel with a rotating shaft of the rotating drum, and a side weir arranged at right angles to the rotating shaft of the rotating drum. And four linear motor coils arranged at four corners of the mold along the scum dam or the side dam, and four power supply devices for supplying excitation power to each of the four linear motor coils And four flow rate detectors arranged at the four corners of the mold and detecting the flow rate of the molten metal injected into the mold; and the flow rates of the molten metal detected by the four flow rate detectors are predetermined. A flow rate judging device for outputting an operation command to a corresponding one of the four power supply devices when the flow rate becomes equal to or less than a threshold value. . 4. Each of the four flow velocity detecting devices is configured to determine a photographing device for photographing an image of molten metal at four corners of the mold, and an autocorrelation function of the image of the molten metal photographed by the photographing device. An autocorrelation function operation unit that calculates every predetermined time, a flow velocity determination unit that determines the flow rate of the molten metal based on the moving distance of the pattern calculated by the autocorrelation function operation unit,
The molten metal flow control device according to claim 3, wherein the flow control device comprises: 5. A molten metal temperature detector, wherein each of the four flow velocity detecting devices detects a temperature of the molten metal based on an amount of infrared rays emitted by the molten metal at the four corners of the mold, and the molten metal temperature detector. 4. The molten metal flow control device according to claim 3, further comprising: a flow rate determining unit configured to determine a flow rate of the molten metal based on the temperature of the molten metal detected in the step. 6. A fluid force detecting member inserted into the molten metal at each of the four corners of the mold, and a fluid force detecting the fluid force of the molten metal received by the fluid force detecting member. The molten metal flow control device according to claim 3, comprising: a detection unit; and a flow velocity determination unit that determines a flow velocity of the molten metal based on the flow force of the molten metal detected by the flow force detection unit.