JPS6082255A - Device and method for adjusting transfer rate of molten metal - Google Patents

Abstract

PURPOSE:To control uniformly the transfer flow rate of a molten metal by disposing a superconductive electromagnet and a normal conductive electromagnet to a molten metal flow part so as to cross each other in the changed directions of the magnetic fields and adjusting the excitation current to the superconductive coils and normal conductive coils. CONSTITUTION:A superconductive electromagnet 5 provided with superconductive coils 5a, 5b and a normal conductive electromagnet 6 provided with normal conductive coils 6a, 6b and an iron core 6c are provided in the nozzle part 3 of a tundish 2 and are so constituted that the respective magnetic fields 7a, 7b intersect orthogonally with each other. Excitation current is then alternately supplied from power sources 8a, 8b to said electromagnets to generate the electromagnetic force in the direction opposite from the flow of the molten steel 1 flowing downward from the nozzle part 3 to a mold 4 to the molten steel, thereby controlling the downflow rate of the molten steel. The transfer rate of the molten steel 1 is controlled in this stage by combining ingeniously the large brake force by the electromagnet 5 and the high speed responsiveness by the electromagnet 6. The transfer rate of the molten steel is thus uniformly adjusted and the quality uniformity of the product is improved.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to a method for adjusting the flow of molten metal when it is fluidly transferred from one container to another, such as in continuous casting of molten steel. The present invention relates to an apparatus and a method for doing so.

[Technical background of the invention and its problems]

Recently, steelmaking automation has become popular for the purpose of saving energy in the steelmaking process. One of them is continuous casting equipment.

In this method, molten steel is temporarily stored in a tundish from a ladle, and then continuously supplied to a mold part from a nozzle provided at the bottom of the tundish, and then steel is manufactured continuously.

Although hot water is supplied relatively continuously from the ladle to the tundish, the amount of the molten metal transferred varies, and therefore the molten steel level in the tundish also fluctuates to some extent. Nevertheless, there is a need for an apparatus and method that can control the amount of steel poured from the tundish into the mold part at a constant level.

In continuous casting equipment, molten steel is slowly fed from a ladle into the tundish at the top of the equipment approximately every hour. On the other hand, pouring steel from the tundish to the mold part,
The pouring is carried out continuously through a nozzle at the bottom of the tundish, and the amount of steel poured varies depending on the level of the molten metal in the tundish. The disadvantage of changing the amount of steel poured is that it can cause problems such as slight variations in the quality of the steel being manufactured and damage to the cast product called breakout. For this reason, conventionally, a valve whose opening degree can be changed mechanically is provided in the nozzle section for adjustment, but this is not possible mechanically. This also applies to the flow rate adjustment of molten metal such as molten aluminum, solder, and zinc.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide an apparatus and a method for adjusting the amount of molten metal to be transferred uniformly when fluidly transferring the molten metal.

[Summary of the invention]

In the present invention, in a device that adjusts the transfer amount when a molten metal containing molten metal is fluidly transferred from one container to another, a superconducting magnet that generates a higher DC magnetic field than a normal conductive electromagnet (described later) in the molten metal flowing section is used. A device in which a superconducting electromagnet with a coil and a normal-conducting electromagnet with a normal-conducting coil that can control reactive excitation current faster than the superconducting electromagnet are interlinked by changing the direction of the magnetic field is used to melt metal. A method for adjusting the transfer amount when molten metal is fluidly transferred from one container to another, includes a superconducting electromagnet having a superconducting coil that generates a DC magnetic field higher than that of a normal-conducting electromagnet (described later) in a molten metal flowing part, and this superconducting electromagnet. A normal-conducting electromagnet with a normal-conducting coil that can control excitation current faster than an electromagnet is arranged so that the direction of the magnetic field is changed and interlinked, and the excitation current of the superconducting coil is used to control slow and large changes in the flowing molten metal. By adjusting the excitation current of the normally conducting coil to control sudden and small changes, the flow transfer of the molten metal is electromagnetically controlled to be uniform according to the speed and speed of the flow fluctuations. It is something.

[Embodiments of the invention]

Embodiment 1 Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 to 3. The casting (1a) is discharged from the nozzle (3) at the bottom of the tundish (2) that stores the molten steel (1).
When supplying hot water to the mold (4) to make hot water, a superconducting electromagnet (
5) are provided, and normally conducting coils (6a), (6b) and iron core (6c
) is provided. Both of these coils (5a), (5b), (6a), (6c) are powered by a power source (8a) that can be controlled so that the excitation current is variable.
), (8b). Figure 2 is the same as Figure 1...
The cross section taken along line -■ shows that superconducting coils (5a) and (5b) are arranged facing each other with nozzle part (3) inserted, and normal conducting coils (6a) and (5b) are disposed in a direction perpendicular to the nozzle part (3).
6b) and the iron core (6c) of its magnetic circuit. That is, the magnetic field (7a) created by the superconducting coils (5a), (5b) and the normal conducting coils (6a), (
The magnetic fields (7b) created by 6b) are configured to be orthogonal to each other.

Next, the effect will be explained.

The molten steel (1) is stored at a relatively high flow rate of 2 to 4 m/tec as it passes through the nozzle part (3) from one vessel (2), which is a container, to the other vessel. Hot water is supplied to the mold (4), which is a container.This force is due to the gravitational force of the difference ΔH between the tundish hot water level and the hot water level in the mold.A superconducting coil is installed in the nozzle part (3) at right angles to the flow direction. 4, when a high DC magnetic field of, for example, a few centimeters to several Tesla is applied, a velocity electromotive force is generated in the molten steel (1) in the nozzle, which is a magnetic fluid, but a short circuit is formed within the fluid as shown in Figure 3. Therefore, current (9a) flows.

This current (9a) flows through the molten metal (1) in the superconducting magnetic field (7a).
) is generated in the direction opposite to the flow direction. This force eventually slows down the flow rate of the molten metal within the nozzle (3). In other words, a braking action will work. The superconducting coils (5a) and (5b) generate a strong magnetic field of several Tesla and have a large braking force. On the other hand, the magnetic field (
7b) is relatively weak, with a strength of less than 1-2 Tesla. However, as with the superconducting coils (5a) and (5b), a brake is applied to the molten metal flowing speed.

A superconducting electromagnet (5) generates a strong magnetic field, but if the magnetic flux suddenly changes, a type of hysteresis loss occurs, and the heat generated breaks the superconductivity. , unable to make rapid magnetic field changes.

In order to keep the amount of poured steel constant through highly accurate flow rate adjustment of molten steel (1), a high degree of responsiveness to various small irregular disturbances is required. However, as mentioned above, the superconducting electromagnet (5) cannot handle this control. Therefore, a normally conducting electromagnet (6) capable of controlling excitation current with high speed response is combined. As shown in Figure 4, changes in the amount of steel poured in conventional equipment include two factors: one that changes sharply and gradually with a period of about 30 seconds per time, and the other that changes rapidly but with a small period of about a few seconds. be. The excitation current of the superconducting coil is adjusted to suppress the change in the amount of steel poured over time,
In case of drastic changes, the excitation current of the normal conducting coil is controlled and adjusted using a Silys-Cleonard device (there is also a Toshiba product name, ``Reovac'') to control the injection current. In Fig. 1, there is a superconducting coil (5a).

Magnetic field due to (5b) and normal current coils (6a), (6b)
Since the magnetic fields are orthogonal to each other, there is no influence or interference with changes in the excitation current of each coil, and control can be adjusted independently for each coil.

If the excitation current changes, the magnetic field strength will also change, and as mentioned above, the braking action will also change. Therefore, when trying to control a constant flow rate, it goes without saying that when the flow rate increases, the excitation current and therefore the magnetic field are strengthened to increase the braking force, and when the flow rate decreases, the excitation current is decreased. Nor.

The effects of this embodiment are as follows. In the case where superconducting coils (5a), (5b) and normal conducting coils (6a), (6b) are installed to control the pouring of a constant amount of steel without any change in the green weight, as shown in Fig. 4, the amount of steel poured is changed. By controlling these currents as described above, a constant amount of steel pouring can be maintained even if there is a disturbance. If a certain amount of steel can be poured, casting can always be performed under certain conditions, and there will be no variation in product quality, making it possible to manufacture steel products with stable quality.

Embodiment 2 FIG. 5 is a block diagram showing a second embodiment of the present invention. This is an embodiment in which the magnetic field generated by the superconducting coils (5 m) and (5b) and the magnetic field generated by the normal conducting miles (6a) and (6b) are provided at different positions in the flow direction of the nozzle.

Even in this case, the same effects as in the first embodiment can be obtained.

Embodiment 3 Figures 6 and 7 show a third embodiment, which shows a configuration example in which the cross-sectional shape of the flow path of the nozzle part (3) in the part where the superconducting magnetic field and the normal conductive magnetic field are applied is changed at the upper and lower portions of the flow path. show. In the case of FIG. 6, the cross-sectional shape of the upper flow path in the portion to which the superconducting magnetic field is applied is circular, and in the case of FIG. 7, the cross-sectional shape of the lower flow path in the portion to which the normal conducting magnetic field is applied is rectangular.

Even in this case, the same effects as in the first embodiment can be obtained.

In addition, the normal conducting coils may be DC excited or AC excited, and they do not necessarily have to be orthogonal to each other, and can be applied not only to continuous casters but also to other molten steel moving devices and transfer devices. It is also applicable to Furthermore, the application of the present invention is not limited to molten steel (1), as long as the molten metal is a magnetic fluid made by molten metal, such as molten aluminum, solder, or zinc.

〔Effect of the invention〕

As explained above, according to the present invention, by skillfully controlling the combination of the large braking force of the superconducting coil and the high-speed response of the normal-conducting coil, the molten metal is controlled by electromagnetic force without relying on a conventional mechanical adjustment mechanism. Since the transfer amount can be adjusted and controlled, problems such as wear and clogging of the adjustment mechanism, which have conventionally been a problem with mechanical adjustment mechanisms, can be solved. The responsiveness regarding transfer amount adjustment is also better compared to mechanical adjustment mechanisms.
Adjustment of excitation current dramatically improves coordination.

Therefore, the method can realize a molten metal transfer amount adjusting device with high reliability and excellent control performance, and it becomes possible to improve the uniformity of product quality and automate equipment.

In the case of a continuous casting machine, controlling the placement of these coils from the tundish to the mold pouring nozzle allows the flow velocity in the nozzle to be kept low due to the braking effect of the magnetic field, so that the components in the mold can be controlled. Control and impurity surfacing are no longer obstructed, and the continuous casting machine can be operated under stable conditions at all times.

Fig. 1 is a partially cutaway elevational view showing a first embodiment of the molten metal transfer rate adjusting device of the present invention, Fig. 2 is a sectional view taken along the line ■-■ in Fig. 1, and Fig. 3 is a Fig. 1 is an explanatory diagram showing the relationship between the magnetic field of the device and the current in the molten metal, Fig. 4 is a curve diagram showing the state of change in the amount of molten metal transferred in the conventional transfer device, and Fig. 5 shows the second embodiment. 6 and 7 are cross-sectional views showing the arrangement of electromagnets for different nozzle positions of the third embodiment.

l... Molten steel which is molten metal 2... Tundish 3 which is one container... Nozzle part 4... Mold 5 which is the other container... Superconducting electromagnets 5a, 5b... Superconducting coils 6. ...Normal conductive electromagnet 6a, 6t = Tokenhiro coil 8a
, 8b...Exciting power supply agent Patent attorney Inoue - Male No. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 1 direction No. 5 Fig. 61 7 order Fig. 7-6C /Otsu α /7A /3 11 1-X-64-6

Claims (4)

[Claims] (1) In a device that adjusts the transfer amount when molten metal is fluidly transferred from one container to another, a superconducting coil that generates a DC magnetic field higher than that of a normal-conducting electromagnet (described later) is installed in the molten metal flowing section. A superconducting electromagnet having a superconducting electromagnet and a normal conducting electromagnet having a normal conducting coil capable of controlling a reactive excitation current faster than the superconducting electromagnet are arranged so as to interlink by changing the direction of the magnetic field. Device. (2) The molten metal transfer rate adjusting device according to claim 1, wherein the direction of the magnetic field to be changed is perpendicular. (3) A normal conductor having a superconducting electromagnet with a superconducting coil that generates a higher DC magnetic field from one container of molten metal than the other, and a normal conductor coil that can control the reactive excitation current faster than this superconducting electromagnet. The electromagnets are arranged so as to interlink with each other by changing the direction of the magnetic field, and control for slow and large changes in the flowing molten metal is performed by adjusting the excitation current of the superconducting coil, and control for sudden and small changes is performed by excitation of the normal conducting coil. A method for adjusting the amount of molten metal transferred, characterized by adjusting the amount of electric current. (4) The method for adjusting the amount of molten metal transferred according to claim 3, characterized in that the direction of the magnetic field to be changed is at right angles.