JP5379643B2 - Continuous casting method and nozzle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a continuous casting method with which a stirring flow is generated at a solidification part in which an ingot is solidified for solving production of segregation in the ingot upon continuous casting, and to provide a nozzle. <P>SOLUTION: In the continuous casting method, a molten metal 3 discharged from a nozzle 4 to a molten metal pool 6 is rolled by a pair of cooling rolls 5, 5 arranged via prescribed intervals so as to produce a planar ingot 7, the flow of the molten metal 3 in the nozzle 4 is made into a forced flow by a stirring flow generation means 40, thus the molten metal 3 is made to flow into the solidification part in which the ingot is solidified in the state of the forced flow. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a continuous casting method and nozzle for continuously casting a metal plate material, and particularly to a continuous casting method and nozzle suitable for casting a thin plate made of a eutectic alloy such as an aluminum alloy having a wide solid-liquid coexistence temperature range. About.

  Conventionally, as a method for producing a thin plate by continuously casting a molten metal such as an aluminum alloy, there is a continuous casting method in which the molten metal is supplied between a pair of cooling rollers via a nozzle and solidified by the cooling roller and rolled. It is known (see, for example, Patent Document 1).

  FIG. 8 is a schematic sectional view showing a continuous casting apparatus using a conventional nozzle. FIG. 9 is a view showing an ingot of an eutectic alloy continuously cast by a conventional twin roll type continuous casting apparatus, where (a) is a perspective view of an ingot having a width of 300 mm and a thickness of 4 mm, and (b) of FIG. It is an enlarged view of the B section of (a). FIG. 10 is a view showing an ingot of an eutectic alloy continuously cast by a conventional twin roll type continuous casting apparatus. FIG. 10 (a) shows a width of 300 mm and thickness continuously cast at a casting speed of 0.6 m / min. The perspective view of a 4 mm ingot, (b) is an enlarged view of the C part of (a), (c) is an enlarged view when the D part of (a) is seen by X-rays.

  As shown in FIG. 8, conventionally, for example, a thin ingot 700 made of an aluminum alloy (hereinafter referred to as “high Mg alloy”) having a thickness of 2 to 10 mm and containing 8 to 14% by mass of magnesium is continuously formed. The continuous casting apparatus 100 for casting includes a dundish 200 that stores a molten metal 300 melted in a melting furnace, a nozzle 400 that discharges the molten metal 300 in the dundish 200, and a nozzle 400 that rotates in opposite directions. Is mainly composed of a pair of cooling rolls 500 and 500 that are rolled while being cooled and solidified.

  When an aluminum alloy thin plate having a wide solid-liquid coexistence temperature range is continuously cast with such a continuous casting apparatus 100, linear segregation 710 is formed on the ingot 700 as shown in FIGS. 9 (a) and 9 (b). Occurs.

  Normally, segregation 710 is likely to occur when the casting speed for continuous casting is high, and is difficult to occur when the casting speed is set to a low speed of about 1 m / min. However, as shown in FIGS. 10 (a) and 10 (b), in the case of a high Mg alloy, the melt concentrated in magnesium is difficult to solidify, and therefore segregation 710 occurs with the magnesium compound as the core.

  Further, as shown in FIG. 10 (c), in the high Mg alloy, the molten metal is solidified in a rectified state, so that a slight concentration fluctuation in the width direction, temperature, and cooling are not uniform. The timing of clotting changes. The small segregation part generated thereby creates a high-concentration low-melting point part, causes a larger change in solidification timing, and generates greater segregation. Therefore, it becomes a solid-liquid interface formed in a mountain range (a state in which mountains and valleys are continuously formed) as indicated by a thin line a in front view.

Japanese Unexamined Patent Publication No. 2000-52000 (FIG. 1)

In the continuous casting apparatus 100 as shown in Patent Document 1 and FIG. 8, in particular, when casting a thin plate made of an alloy or the like having a wide solid-liquid coexistence temperature range such as a high Mg alloy (solid-liquid coexistence temperature range is 40K or more) There was a problem that segregation 710 was generated in the ingot 700 (cast slab) due to a magnesium-enriched melt that hardly solidified.
The ingot 700 in which the segregation 710 was made was inferior in strength and elongation, and had a problem that it could not be used as various materials.

  Therefore, the present invention has been made in view of the above problems, and in order to eliminate the occurrence of segregation in the ingot during continuous casting, a stirring flow is generated in the solidified portion where the ingot is solidified. It is an object of the present invention to provide a continuous casting method and a nozzle that are generated.

In order to solve the above-mentioned problem, the continuous casting method according to claim 1 is a method in which the molten metal discharged from the nozzle to the molten metal pool is rolled by a pair of cooling rolls arranged at a predetermined interval. In the continuous casting method for producing an ingot, an electromagnetic force is generated in the molten metal in the nozzle by using a permanent magnet of a stirring flow generating means , and a forced flow is generated using the electromagnetic force, and the inside of the nozzle is generated. Discharging the molten metal from the nozzle outlet arranged to be inserted between the pair of cooling rolls into the molten metal pool, and solidifying while stirring the unsolidified molten portion between the pair of cooling rolls. Features.

According to such a configuration, the continuous casting method generates a forced flow by the stirring flow generation means and changes the flow of the molten metal in the nozzle to a stirring flow, whereby the molten metal discharged from the nozzle is cooled as a stirring flow. It flows into the molten metal pool between rolls. The molten metal is cooled and solidified by a cooling roll in a state where a metal component that is difficult to solidify is stirred and dispersed in an unsolidified molten portion in the molten metal pool.
Further, according to such a configuration, the stirring flow generating means becomes a stirring flow because the flow of the molten metal in the nozzle is disturbed by the forced flow by the electromagnetic force.

The continuous casting method according to claim 2 is the continuous casting method according to claim 1, wherein the stirring flow generation means is provided with electrodes on the left and right side walls of the flow path in the nozzle, respectively, An electromagnetic force is generated by causing a current to flow between the electrodes through the molten metal, which is a conductor, between the magnetic fields of the permanent magnets provided on the upper and lower sides, thereby generating a forced flow in the nozzle. Features.

According to this configuration, the stirring flow generating means generates a forced flow by an electromagnetic force generated by the permanent magnet , thereby causing the flow of the molten metal in the nozzle to be a stirring flow.

A continuous casting method according to a third aspect is the continuous casting method according to the first or second aspect , wherein the Reynolds number of the molten metal flowing in the nozzle is 2500 or more .

According to this configuration, when the Reynolds number Re of the molten metal flowing in the nozzle is 2500 or more, the flow of the molten metal becomes a more disturbed stirring flow.

The continuous casting method according to claim 4 is the continuous casting method according to claim 1 , wherein the stirring flow generating means is vertically moved into the nozzle by magnets provided alternately in the width direction outside the nozzle. A flow path divided by a plurality of partition walls arranged in parallel at predetermined intervals in the width direction in the nozzle by flowing a current in the width direction of the nozzle through a molten metal flowing in the nozzle By generating a force in the opposite direction to the molten metal, it is possible to prevent segregation from occurring in the ingot .

According to such a configuration, in the continuous casting method, a current is passed in the nozzle width direction through the molten metal in the nozzle, a magnetic field is generated in the vertical direction by the magnet, and a plurality of them are arranged in parallel in the nozzle at predetermined intervals in the width direction. Force in the opposite direction is generated for each flow path divided by the partition walls. In the molten metal flowing through each flow path of the nozzle, a force in the opposite direction to the molten metal for each flow path is generated, so that a force in the same direction and a force in the opposite direction flow with respect to the molten metal flow direction. It occurs alternately on each road. For this reason, in a flow path in which a force in the same direction as the forward flow direction (casting direction) of the molten metal is generated, the force becomes a suction force of the forward flow, and forced flow is generated to increase the flow of the molten metal. . In the flow path in which a force in the direction opposite to the flow direction of the forward flow of the molten metal is generated, the force becomes a repulsive force of the flow, and the reverse flow (forced flow) is generated by sucking the forward flow from the forward flow side. The fast-flowing forward melt flows into the melt pool from the nozzle in a stirring flow state. The reverse flow molten metal is blown into the nozzle. In the molten metal in a state of stirring flow in the molten metal pool, a metal component that is difficult to solidify is stirred and dispersed, and in this state, it is cooled and solidified by a cooling roll, thereby causing segregation in the ingot. Can be prevented.

The continuous casting method according to claim 5 is the continuous casting method according to claim 4 , wherein the molten metal contains magnesium, and the stirring prevents the occurrence of segregation of magnesium. Features.

According to such a configuration, in the continuous casting method , the molten metal in a state of stirring flow in the molten metal pool is stirred and dispersed with the metal component that is difficult to solidify, and in that state, the molten metal is cooled and solidified by the cooling roll. Therefore, it is possible to prevent segregation of magnesium from occurring in the ingot.

The nozzle according to claim 6 is a nozzle used in a continuous casting apparatus for producing a plate-shaped ingot by rolling molten metal from a dundish with a pair of cooling rolls arranged at a predetermined interval. The nozzle supplies the molten metal from the dandish between the cooling rolls, and allows current to flow between the electrodes provided on the left and right side walls of the flow path in the nozzle via the molten metal, and is divided by a partition wall. Further, the present invention is characterized in that a stirring flow generating means for forcibly flowing the molten metal by generating a force in the opposite direction to the molten metal for each flow path is provided .

  According to such a configuration, when the nozzle that supplies the molten metal between the cooling rolls passes an electric current between the electrodes on the left and right side walls in the nozzle via the molten metal, the nozzle is supplied to the molten metal for each flow path divided by the partition wall. A force in the opposite direction is generated. The force becomes a suction force (pressing force) or a repulsive force with respect to the flow of the molten metal in each flow path, forcibly flowing the molten metal, disturbing the flow of the molten metal and making it a stirring flow. For this reason, the molten metal discharged from the nozzle flows into the molten metal pool in a stirring flow state. The molten metal in a stirring flow state is cooled and solidified by a cooling roll in a state where a metal component that is difficult to solidify is stirred and dispersed in the molten metal pool. For this reason, even if the metal has a wide temperature range for solid-liquid coexistence, when solidifying, the solid component that is difficult to solidify and has a low melting point is stirred, so that the solid phase metal and the liquid phase component are uniformly dispersed. It becomes a state of coexistence. As a result, it is possible to prevent segregation from occurring in the ingot.

  The nozzle of Claim 7 is a nozzle of Claim 6, Comprising: The said partition wall is provided in the flow path in the said nozzle along the direction in which the said molten metal is discharged, and the said flow path A plurality of the nozzles are arranged in parallel in the width direction at a predetermined interval, and the nozzles are arranged along the width direction of the flow path, with stirring flow generating means for disturbing the flow of the molten metal before the molten metal flows from the nozzle into the molten metal pool. And a communication port formed at each partition wall position on a straight line.

  According to this configuration, the flow path in the nozzle is divided into a plurality of flow paths by the partition wall provided along the casting direction of the molten metal (forward flow direction). The partition walls of the plurality of flow paths are formed with communication ports that communicate with the respective flow paths, so that the leftmost inner wall and the rightmost inner wall of the nozzle flow path communicate with each other. It is possible to conduct current between the inner walls at the left and right ends of the path by interposing a conductive molten metal in the communication port. When current flows between the left and right outer walls of the flow path through the molten metal in the flow path, the stirring flow generating means is driven. For this reason, before the molten metal exits from the flow path in the nozzle into the molten metal pool, the flow is agitated by the generation of forced flow by the agitating flow generating means in the nozzle. Then, the molten metal in the flow path in the nozzle through which the forward flow flows becomes a stirring flow whose flow is disturbed by being sucked into the adjacent flow path side through the communication port, and flows into the molten metal pool in the state of the stirring flow. . The molten metal in a stirring flow state is cooled and solidified by a cooling roll in a state where a metal component that is difficult to solidify in the molten metal pool is stirred and dispersed.

  The nozzle according to claim 8 is the nozzle according to claim 7, wherein the stirring flow generating means is provided on the left and right side walls in the flow path at a position on a straight line where the communication port is formed. And a plurality of magnets provided on the upper and lower outer sides of the nozzle so as to generate a magnetic field in the vertical direction.

  According to such a configuration, before the molten metal comes out of the flow path in the nozzle into the molten metal pool, the nozzle places the molten metal that is a conductor between the electrodes of the stirring flow generating means provided on the left and right side walls of the flow path through which the molten metal flows. When a current is passed through, a force in the opposite direction is generated with respect to the molten metal for each flow path divided by the partition wall. The force is generated in a direction perpendicular to both the upper and lower magnetic field directions and the width direction of the current flow as a current flows through the molten metal in each flow path in the magnetic field generated by the magnet. The force is forward flow (casting direction) with respect to the flow direction of the molten metal flowing in each flow path of the nozzle by arranging a plurality of magnets in which different magnetic poles are alternately arranged on the upper and lower sides of the nozzle. The force in the same direction and the force in the opposite direction are alternately generated for each flow path. For this reason, in the flow path in which a force in the same direction as the flow direction of the molten metal is generated, the force becomes a suction force (pressing force) of the forward flow, and forced flow is generated, so that the flow of the molten metal is accelerated. In the flow path in which a force in the direction opposite to the flow direction of the molten metal is generated, the force becomes a repulsive force of the flow, sucking forward molten metal flowing in the adjacent flow path, and generating a reverse flow (forced flow). For this reason, only the fast-flowing forward molten metal flows into the molten metal pool in a stirred flow state by the reverse flow. The molten metal in the state of stirring flow can be prevented from being segregated in the ingot because the metal component that is difficult to solidify in the molten metal pool is cooled and solidified in a state of being stirred and dispersed. .

  The nozzle according to claim 9 is the nozzle according to claim 8, wherein the plurality of magnets are permanent magnets in which different magnetic poles are alternately arranged along a straight line on which the communication port is formed. It is characterized by becoming.

  According to this configuration, the plurality of magnets are made of permanent magnets, so that the magnets can be reduced in size and installed on the nozzles disposed between the cooling rolls.

  The nozzle according to claim 10 is the nozzle according to claim 8 or 9, wherein a cutout groove extending in the width direction is formed on each of upper and lower outer surfaces of the nozzle, and the cutout groove is provided in the cutout groove. And a magnet unit that houses the plurality of magnets.

  According to such a configuration, the nozzle is installed in the vicinity of the flow path in the nozzle by separating the magnet from the cooling roll by providing a magnet unit containing a plurality of magnets in the cutout grooves formed on the upper and lower outer surfaces of the nozzle. It becomes possible to do.

  A nozzle according to an eleventh aspect is the nozzle according to the eighth or ninth aspect, further comprising a magnet cooling device that cools the plurality of magnets.

  According to such a configuration, the nozzle can cool the magnet to a temperature within the use limit range by the magnet cooling device.

  The nozzle according to claim 12 is the nozzle according to claim 11, wherein the magnet cooling device is provided in the magnet unit, and includes a ventilation path through which air is supplied to air-cool the magnet unit. It is characterized by that.

  According to this configuration, the magnet can be air-cooled to a temperature within the use limit range by providing the air passage for air-cooling the magnet unit in the magnet unit.

  The nozzle of Claim 13 is a nozzle of Claim 10, Comprising: The said magnet unit is each interposed between the said notch groove and each said magnet, and is provided with the spacer between nozzles which consists of heat insulating materials. It is characterized by being.

  According to such a configuration, the magnet unit suppresses the radiant heat from the nozzle due to the heat of the molten metal from being transmitted to the magnet by interposing the inter-nozzle spacer of the heat insulating material between the notch groove and each magnet. Can do.

  The nozzle according to claim 14 is the nozzle according to claim 10 or claim 13, wherein the magnet unit includes an inter-magnet spacer interposed between the magnets, the inter-magnet spacer, and the plurality of the inter-magnet spacers. And a case made of a non-magnetic metal that houses a magnet.

  According to such a configuration, the magnet unit has a non-magnetic metal case containing a spacer between magnets and a plurality of magnets, and by fixing the case to the nozzle, each magnet is set in advance for each nozzle. It can be easily arranged at a predetermined position.

  A nozzle according to a fifteenth aspect is the nozzle according to any one of the eighth to fourteenth aspects, wherein each of the magnets is made of a rare earth magnet or an alnico magnet.

  According to this configuration, each magnet is made of a rare earth magnet or an alnico magnet, so that it has strong magnetism and excellent heat resistance.

According to the continuous casting method of the first aspect of the present invention, the forced flow is generated by the stirring flow generating means, and the flow of the molten metal in the nozzle is changed to the stirring flow, thereby the inside of the molten pool between the nozzle and the cooling roll. The molten metal sent to the flow into the stirring flow. For this reason, the molten metal in the molten metal pool is agitated, uniformly dispersed and mixed, and cooled and solidified by the cooling roll, so that segregation occurs in the ingot. Can be prevented. As a result, a high quality high alloy material plate can be obtained.
Moreover, according to the continuous casting method which concerns on Claim 1 of this invention, the stirring flow generation | occurrence | production means can make the flow of the molten metal in a nozzle into a stirring flow with an electromagnetic force.

According to the continuous casting method according to claim 2 of the present invention, the stirring flow generating means can generate a forced flow by the electromagnetic force of the permanent magnet, so that the flow of the molten metal in the nozzle can be a stirring flow. The structure of the stirring flow generating means can be simplified and the overall size can be reduced.

According to the continuous casting method according to claim 3 of the present invention, when the Reynolds number Re of the molten metal flowing in the nozzle is 2500 or more, segregation occurs in the ingot by using the molten metal flow as a stirring flow. Can be eliminated.

According to the continuous casting method of claim 4 of the present invention, a force is generated by flowing an electric current through the molten metal in the width direction in the nozzle in which the magnetic field is generated in the vertical direction, and the molten metal in the nozzle is By making the flow a turbulent stirring flow, components that are difficult to solidify in the molten metal can be stirred and solidified in a uniformly dispersed state. For this reason, it is possible to eliminate the occurrence of segregation in the ingot. As a result, even when a thin metal plate such as a high Mg alloy with a wide solid-liquid coexisting temperature range is cast, the thin plate can be used as various materials by preventing segregation and cracking in the ingot. The ingot can be produced in a stable state.

According to the continuous casting method according to claim 5 of the present invention, to prevent the occurrence of segregation and cracking due to magnesium in the ingot to produce a stable state of sheet ingot can be used as various materials be able to.

  According to the nozzle according to claim 6 of the present invention, the forced flow is generated by flowing a current between the electrodes on the left and right side walls in the nozzle to generate a forced flow for each flow path divided by the partition wall. The stirring flow can be generated by changing the flow of the molten metal. For this reason, the molten metal discharged from the nozzle can be cooled and solidified by the cooling roll in a state where the metal component which is difficult to solidify is stirred and dispersed by flowing into the molten metal pool in a stirring flow state. As a result, even when the solid-liquid coexistence temperature range is wide, when solidifying, the solid component that is difficult to solidify and has a low melting point is agitated to uniformly disperse the solid phase metal and the liquid phase component. It becomes a state of coexistence. As a result, it is possible to prevent segregation from occurring in the ingot.

  According to the nozzle of claim 7 of the present invention, the flow path in the nozzle is divided into a plurality of flow paths by the partition wall, and the communication port is formed in the partition wall, so that the stirring flow When the forcible flow is generated by the generating means, the molten metal in each flow channel freely flows to the adjacent flow channel through the communication port, and the flow of the molten metal in the entire nozzle can be agitated. For this reason, the molten metal discharged from a nozzle can be poured in the molten metal pool in the state of the stirring flow in which the metal component which is hard to solidify is stirred.

  According to the nozzle of claim 8 of the present invention, by flowing a current between the electrodes in each flow path in the magnetic field by the magnet, both the direction of the upper and lower magnetic field and the width direction of the current flow. Force can be generated in a perpendicular direction. The force is the same as the forward flow of the molten metal (casting direction) and the force in the opposite direction is generated alternately for each flow path to make the molten metal flow forward (forced flow) faster or adjacent flow paths. The reverse flow (forced flow) can be generated by sucking the forward flow of molten metal flowing through. For this reason, the molten metal in the nozzle flows into the molten metal pool as a stirring flow disturbed by the forward flow and the reverse flow generated by the forced flow. Since the molten metal in the molten metal pool is cooled and solidified by the cooling roll in a state where the metal components that are difficult to solidify are stirred and dispersed, segregation can be prevented from occurring in the ingot.

  According to the nozzle of the ninth aspect of the present invention, the magnet disposed in the nozzle is composed of a permanent magnet having a simple structure and capable of reducing the overall size. Even if it is a small space in the outer peripheral portion of the nozzle arranged in such a manner, it can be installed.

  According to the nozzle of claim 10 of the present invention, the magnet can be cooled to about 350 ° C. or less, which is the use limit temperature, by the magnet cooling device.

  According to the nozzle of claim 11 of the present invention, the magnet unit can be installed in the vicinity of the flow path of the molten metal by being provided in the notch grooves formed on the upper and lower outer surfaces of the nozzle. In addition, since the magnet is unitized by installing a large number of magnets in the magnet unit, if the magnet unit is fixed to the nozzle, a large number of magnets can be attached to the nozzle at one time. Can be reduced.

  According to the nozzle of claim 12 of the present invention, since the magnet unit can be air-cooled to a temperature within the use limit range by providing the air passage in the magnet unit, the magnet is installed at a high temperature location. Enable.

  According to the nozzle of the thirteenth aspect of the present invention, by interposing the inter-nozzle spacer of the heat insulating material between the notch groove and each magnet, the radiant heat of the nozzle due to the molten metal is suppressed from being transmitted to the magnet. Therefore, it is possible to install a magnet having a low use limit temperature.

  According to the nozzle of the fourteenth aspect of the present invention, the magnet unit fixes the plurality of magnets at predetermined positions of the nozzle by fixing the non-magnetic metal case containing the inter-magnet spacer and the plurality of magnets to the nozzle. Since each can be easily attached in the positioned state, the number of assembling steps can be reduced and the structure can be simplified.

  According to the nozzle of the fifteenth aspect of the present invention, since each magnet is made of a rare earth magnet or an alnico magnet, the magnet unit can be miniaturized because it has strong magnetism and excellent heat resistance. As a result, the magnet unit can be installed in a nozzle disposed in a narrow place near the molten metal pool between the cooling nozzles.

It is a schematic sectional drawing which shows the continuous casting apparatus using the nozzle which concerns on embodiment of this invention. It is a principal part schematic expanded sectional view which shows the continuous casting apparatus using the nozzle which concerns on embodiment of this invention. It is a principal part schematic expanded sectional view which shows the continuous casting apparatus using the nozzle which concerns on embodiment of this invention. It is the enlarged view which looked at the E section of FIG. 2 from the top. It is FF sectional drawing of FIG. It is a block diagram of the continuous casting apparatus using the nozzle which concerns on embodiment of this invention. It is a figure which shows an example of the ingot of the metal continuously cast with the continuous casting apparatus using the nozzle which concerns on embodiment of this invention, (a) is a perspective view of the high Mg alloy of width 300mm and thickness 4mm, (b) ) Is an enlarged view of a G portion in (a). It is a schematic sectional drawing which shows the continuous casting apparatus using the conventional nozzle. It is a figure which shows the ingot of the eutectic-type alloy continuously cast with the conventional twin roll type continuous casting apparatus, (a) is a perspective view of the ingot of width 300mm and thickness 4mm, (b) is a figure of (a). It is an enlarged view of the B section. It is a figure which shows the ingot of the eutectic type alloy continuously cast with the conventional twin roll type continuous casting apparatus, (a) is a casting of width 300mm and thickness 4mm continuously cast at a casting speed of 0.6m / min. The perspective view of a lump, (b) is an enlarged view of the C part of (a), (c) is an enlarged view when the D part of (a) is seen with X-rays.

  Hereinafter, an embodiment for carrying out the invention will be described with reference to FIGS.

≪Construction of continuous casting equipment≫
As shown in FIG. 1, the continuous casting apparatus 1 is an apparatus which continuously casts the plate-shaped ingot 7 from the molten metal 3 toward the horizontal direction. More specifically, the continuous casting apparatus 1 is configured such that the molten metal 3 from the dundish 2 is placed in a molten pool 6 formed between a pair of cooling rolls 5 and 5 that are arranged at predetermined intervals and rotate in opposite directions. This is a twin-roll continuous casting apparatus for producing a plate-shaped ingot 7 by injecting molten metal 3 discharged from a nozzle 4 and solidifying it while rolling. The continuous casting apparatus 1 includes a dundish 2 in which the molten metal 3 is stored, a nozzle 4 to which the molten metal 3 in the dundish 2 is supplied, and before the molten metal 3 comes out of the nozzle 4 into the molten metal pool 6. A stirring flow generating means 40 forcibly flowing the molten metal 3 to disturb the flow, a pair of cooling rolls 5 and 5 rotating in opposite directions, and a molten pool 6 formed between the cooling rolls 5 and 5. It is prepared for. This continuous casting apparatus 1 is an apparatus that uses a nozzle 4 and is particularly optimal for continuously casting an ingot 7 made of a eutectic alloy thin plate such as an aluminum alloy.

≪Dandish composition≫
The dundish 2 is a furnace for temporarily storing the molten metal 3 melted in a melting furnace (not shown) in a heated state, and the molten metal 3 is placed on the lower side wall via the supply pipe 21 in the nozzle 4. A supply port 2a for supplying is formed.

<Composition of molten metal and ingot>
The molten metal 3 is a metal melted in the melting furnace (not shown), and is made of a eutectic alloy such as a high Mg alloy having a wide solid-liquid coexistence temperature range (for example, 40 K or more). In the case of pure aluminum, the melting point is about 660 ° C. The molten metal 3 may be a high-concentration eutectic alloy, and may be an Fe alloy, Si alloy, Mn alloy, Cu alloy, Zn alloy, or the like in addition to an Al alloy or an Mg alloy.
The ingot 7 is a slab cast by the continuous casting apparatus 1 and solidified by the molten metal 3, and is cast into a long thin plate having a width of 300 mm and a thickness of 2 to 10 mm, for example.

≪Nozzle configuration≫
As shown in FIG. 1, the nozzle 4 is a nozzle tip that discharges the molten metal 3 of the dundish 2 to the molten metal pool 6 between the cooling rolls 5 and 5, and the flow path 4 b that communicates with the supply port 2 a of the dundish 2. It consists of a substantially rectangular tube shape to be formed. As shown in FIG. 2, the nozzle 4 is formed at notches 4a and 4a formed on the upper and lower outer surfaces 4e and 4e of the nozzle 4, a channel 4b through which the molten metal 3 flows, and a tip of the channel 4b. A discharge port 4c, curved surfaces 4d and 4d formed around the discharge port 4c, a plurality of partition walls 4f arranged in parallel in the width direction in the flow channel 4b at predetermined intervals, and a width direction of the flow channel 4b The left and right side walls 4h and 4i (see FIG. 4) having the communication ports 4g formed in the partition walls 4f that are straight along the lines and the electrodes 41 and 42 (see FIG. 4) formed in the width direction of the communication ports 4g. And the stirring flow generating means 40. In other words, the nozzle 4 has a plurality of flow paths 4b provided with a plurality of partition walls 4f along the direction in which the molten metal 3 is discharged.

As shown in FIGS. 2 and 3, the cutout grooves 4 a and 4 a are grooves for installing the magnet unit 8, and are formed on the upper and lower outer surfaces 4 e and 4 e near the tip of the nozzle 4 in the width direction. It consists of a groove having a concave cross section.
As for the flow path 4b, the front-end | tip part side is formed in the substantially funnel shape, and the height of the up-down direction of a front-end | tip part is formed narrowly. A plurality of partition walls 4f and communication ports 4g are formed in the narrowed portion in the flow path 4b.
As shown in FIG. 2, the discharge port 4 c is a part from which the molten metal 3 is discharged, and is disposed so as to be inserted in the vicinity of the roll kiss point between the cooling rolls 5 and 5.
The curved surfaces 4d and 4d are arc-shaped surfaces as viewed from the side formed along the outer peripheral surfaces of the cooling rolls 5 and 5, and are formed on the outer upper and lower surfaces of the front end portion of the flow path 4b. The curved surfaces 4d and 4d are disposed between the cooling rolls 5 and 5 via a slight gap. The notched grooves 4a and 4a are formed in the curved surfaces 4d and 4d along the axes of the cooling rolls 5 and 5, respectively.

<Configuration of partition wall>
As shown in FIGS. 4 and 5, the partition wall 4 f is a partition wall that extends and partitions the flow path 4 b in the nozzle 4 in the direction (arrow e direction) in which the molten metal 3 is discharged. A plurality of the partition walls 4 f are arranged in parallel in the width direction of the nozzle 4 at a pitch interval of the magnets 81 of the magnet unit 8 (interval greater than the width of the magnet 81 in the left-right direction). Each partition wall 4f is formed of a plurality of thick plate-like members in a state where a communication port 4g is formed at the center and is divided in half in the direction of the flow path 4b. By this partition wall 4f, the flow path 4b in the nozzle 4 is temporarily divided into a plurality. Hereinafter, a case where the flow path 4b in the nozzle 4 is divided into six by the partition walls 4f arranged in parallel in the width direction (left-right direction) will be described as an example.

<Composition of communication port>
As shown in FIG. 4, the communication port 4g is connected to each flow path 4b from the electrode 41 side of one side wall 4h with respect to the flow path 4b in the nozzle 4 divided into six by forming five partition walls 4f. By connecting to the electrode 42 side of the other side wall 4i across, the current is conducted between the electrodes 41 and 42 between the magnetic fields of the upper and lower magnets 81 and 81 via the molten metal 3 as a conductor. The through hole is formed so as to generate an electromagnetic force. The communication port 4g is located on a straight line along the width direction of the flow path 4b to each partition wall 4f between the electrodes 41 and 42 so that the flow paths 4b in the nozzle 4 divided into six communicate with each other. Is formed.

<Configuration of side wall>
As shown in FIGS. 4 and 5, the left and right side walls 4h and 4i of the nozzle 4 are formed by thick plates formed vertically, and electrodes 41 and 42 are integrally provided in the left and right width directions of the communication port 4g. ing. The side walls 4h and 4i are formed in a tapered shape when viewed from the side as the nozzle 4 is inserted and disposed between the adjacent cooling rolls 5 and 5 (see FIG. 2).

≪Configuration of stirring flow generation means≫
The stirring flow generating means 40 is a stirring flow generating device for making the flow of the molten metal 3 flowing in the upstream nozzle 4 into a stirring flow (high-speed flow) in order to make the solidification part of the molten metal pool 6 a stirring flow. . The stirring flow generating means 40 is disposed on the upper and lower outer sides of the nozzles 4 and the electrodes 41 and 42 provided on the left and right side walls 4h and 4i of the flow path 4b at the straight position where the communication ports 4g and 4g are formed. A magnet unit 8 having a plurality of magnets 81, a magnet cooling device 9 for cooling the magnet unit 8 (see FIG. 6), and a power supply drive control device 10 for supplying current to the electrodes 41 and 42 and the magnet cooling device 9 ( 6). The stirring flow generating means 40 is provided for each flow path 4b divided by the partition wall 4f by causing a current to flow in the width direction of the nozzle 4 through the molten metal 3 between the electrodes 41 and 42 in which a magnetic field is generated by the magnets 81 and 81. A force in the opposite direction (a direction different from the discharge direction of the nozzle 4) is generated with respect to the molten metal 3 to disturb the flow of the molten metal 3 flowing through the flow path 4b in the nozzle 4, and segregation occurs in the ingot 7. It is a device that prevents it from being generated.

<Configuration of electrode>
The electrodes 41 and 42 are positive and negative electrode conductors for supplying electricity to the molten metal 3 in each flow path 4b in the nozzle 4, and are made of graphite or the like integrally provided on the left and right side walls 4h and 4i. Become. The electrodes 41 and 42 are electrically connected to each other when the molten metal 3 is interposed between the left and right electrodes 41 and 42. As shown in FIG. 6, the electrodes 41 and 42 are electrically connected to the electrode control device 11 of the power supply drive control device 10.

≪Configuration of magnet unit≫
The magnet unit 8 is a single unit containing a plurality of magnets 81 and is formed in a thick plate shape. The magnet unit 8 is arranged in a pair of upper and lower N poles and S poles on the upper and lower outer sides of the nozzle 4, and different magnetic poles N and S are alternately arranged in the left and right direction along the straight line on which the communication port 4g is formed. A plurality of magnets 81 provided so as to generate a magnetic field in the vertical direction from the N pole to the S pole, inter-nozzle spacers 83 interposed between the magnets 81 on the cutout grooves 4a and 4a, and the magnets 81, respectively. , 81, an intermagnet spacer 84, a case 82 made of a nonmagnetic metal that accommodates the intermagnet spacer 84 and the plurality of magnets 81, and an air passage 85 for air-cooling the magnet 81. .

<Composition of magnet>
The magnet 81 shown in FIGS. 5 and 6 is made of a rare earth magnet such as a samarium cobalt magnet having a strong magnetic force, or a permanent magnet such as an alnico magnet, and has a magnetic flux density of about 0.1 (T) or more. For example, the magnet 81 having a length of 20 mm, a width of 10 mm, and a thickness of 5 mm is formed on a straight line in which the communication ports 4 g and 4 g are formed at a pitch interval of 20 mm on the upper and lower sides of the nozzle 4. Along the direction, the magnetic poles of the S pole and the N pole are alternately changed to be arranged in a row in the width direction on the bottom surface of the notch groove 4a on the upper and lower sides of the nozzle 4 (see FIG. 3). As shown in FIG. 4, the magnet 81 is a nozzle on an intermediate position between the communication ports 4g, 4g arranged in a horizontal row on each partition wall 4f (the center portion of each flow path 4b divided into six). 4 are arranged with the S pole and N pole in the vertical direction. In addition, since the melting point of the aluminum alloy which is the molten metal 3 is as low as about 660 ° C., the magnet 81 is further insulated by the inter-nozzle spacer 83 and cooled by the magnet cooling device 9. Since the magnet 81 can be within the use limit temperature range in which a desired magnetic force is generated, it can be installed in the nozzle 4. The dimensions may be changed as appropriate according to the sizes of the nozzle 4, the molten metal 3 and the ingot 7.

<Configuration of spacer between nozzles>
As shown in FIG. 5, the inter-nozzle spacer 83 is a thick plate-like member interposed between each magnet 81 and the nozzle 4, and suppresses the magnet 81 from being heated by the heat of the molten metal 3. In addition, it is formed of a heat insulating material. The vertical and horizontal lengths of the inter-nozzle spacer 83 are, for example, formed in dimensions that match the magnet 81.

<Configuration of spacer between magnets>
As shown in FIG. 5 and FIG. 6, the inter-magnet spacer 84 is a member that is interposed between the magnets 81 and supports the magnets 81, and is arranged side by side in a state where two magnets stand between the magnets 81. . The inter-magnet spacer 84 is formed of a metal such as aluminum, for example.

<Case configuration>
As shown in FIGS. 5 and 6, the case 82 accommodates the magnets 81, the inter-nozzle spacers 83, and the inter-magnet spacers 84 so that these members can be attached to the nozzle 4 at a time. Is the body. The case 82 is formed of a non-magnetized nonmagnetic metal such as nonmagnetic stainless steel.

<Configuration of air passage>
The ventilation path 85 constitutes a part of the magnet cooling device 9 described later, and is a flow path for cooling the magnet unit 8 through the inside of the case 82 with air as a refrigerant sent by the fan 91. The ventilation path 85 includes a space (flow path) formed between the inner wall of the substantially square cylindrical case 82 and the magnet 81 and the inter-magnet spacer 84 installed inside the case 82. The air passage 85 is formed from the right end to the left end of the magnet unit 8.

≪Configuration of magnet cooling device≫
As shown in FIG. 6, the magnet cooling device 9 is a cooling device for cooling the magnet 81 to a usable temperature. For example, a fan 91 that sends air to a plurality of magnets 81 and the fan 91 are rotated. A fan motor 92, an air passage 85 provided in the magnet unit 8 for flowing air for air-cooling the magnet unit 8, an air supply passage 93 connecting the air passage 85 and the fan 91, and the fan motor 92 The fan control device 13 that controls the driving of the motor and the power source 12 that supplies power for rotating the fan motor 92 are provided. The magnet cooling device 9 used as the magnet 81 is a rare earth magnet samarium-cobalt magnet, which is cooled to a use limit temperature of about 350 ° C. or less, and an alnico magnet is cooled to a use limit temperature of about 400 ° C. or less. To do.

≪Configuration of power supply drive control device≫
The power supply drive control device 10 is a device that supplies current to the electrodes 41 and 42 and the fan motor 92, and includes, for example, the electrode control device 11 and the power supply 12. The power supply drive control device 10 supplies, for example, a 50 A direct current to the electrodes 41 and 42. Note that the configurations of the power supply drive control device 10 and the magnet cooling device 9 shown in FIG. 6 are merely examples, and the configuration is not limited thereto, and the configurations may be changed as appropriate.

≪Cooling roll configuration≫
As shown in FIG. 2, the cooling rolls 5 and 5 are rolls that form an ingot 7 having a predetermined thickness by rolling the molten metal 3 discharged from the discharge port 4 c of the nozzle 4 while removing heat. The cooling rolls 5 and 5 are formed by disposing a horizontal cylindrical upper roll 5a and a lower roll 5b facing each other through a gap (melt pool 6). The cooling rolls 5 and 5 are each provided with a roll cooling device 51 and a rotation drive motor device (not shown) that rotates the cooling rolls 5 and 5 at a low speed.

<Configuration of roll cooling device>
As shown in FIG. 1, the roll cooling device 51 is a device that cools the molten metal 3 to an appropriate temperature for continuously casting the cooling rolls 5 and 5 that are in contact with the molten metal 3 in order to cool and solidify the molten metal 3. For example, it consists of a water jacket. The roll cooling device 51 includes, for example, water passages 51a and 51a through which cooling water supplied from a cooling water circulation supply device (not shown) circulates, and the water passage 51a, The cooling water sent to 51a circulates through the water passages 51a and 51a, thereby exchanging heat and cooling the cooling rolls 5 and 5.

≪Composition of molten metal pool≫
The molten metal pool 6 is a place where the molten metal 3 discharged from the nozzle 4 is poured to temporarily store the molten metal 3, and the molten metal 3 is rolled while being cooled by the upper and lower cooling rolls 5, 5. The molten pool 6 has a pair of cooling rolls 5, 5 disposed in the vicinity of a roll kiss point between the discharge port 4 c of the nozzle 4 and the upper and lower cooling rolls 5, 5 with a thickness interval of the ingot 7. It consists of a gap formed by the outer peripheral surface. For this reason, the molten metal 3 that has been forced to flow in the nozzle 4 in front of the molten metal pool 6 by the electromagnetic force generated between the electrodes 41 and 42 and the magnetic force of the magnet 81 becomes a stirring flow. 6 is cooled by the cooling rolls 5 and 5 while flowing in a stirring flow state.

≪Action≫
Next, the operation of the continuous casting method and the nozzle according to the embodiment of the present invention will be described.
As shown in FIG. 1, when casting the ingot 7 with the continuous casting apparatus 1, first, the molten metal 3 in the dundish 2 is slowly poured into the nozzle 4 from the supply port 2a. As shown in FIG. 2, the molten metal 3 sent into the nozzle 4 has a narrow flow passage 4b, so that the flow velocity is increased and the discharge port 4c passes between the partition walls 4f and between the electrodes 41 and 42. Is discharged into the molten metal pool 6.

  As shown in FIG. 4, at this time, in each of the flow paths 4b divided into six by the five partition walls 4f, they are different from each other in the vertical direction along the straight line on which the communication ports 4g and 4g are formed. The magnets 81 of the magnetic poles N and S are alternately arranged with the N pole and the S pole at a pitch interval (predetermined interval) of the partition wall 4f, and a magnetic field in the opposite direction is generated for each flow path 4b. That is, a magnetic field that alternately rises and falls is generated in the adjacent flow path 4b, such as from the bottom to the top in the leftmost flow path 4b and from the top to the bottom in the adjacent flow path 4b. A current is supplied from the power supply drive control device 10 to the electrodes 41 and 42 in the width direction of the flow path 4b. Since the molten metal 3 flows and is filled between the electrodes 41 and 42, the electrodes 41 and 42 are in a state of being conducted with a conductor. For this reason, when an electric current flows from one electrode 41 to the other electrode 42 side through the molten metal 3 in the nozzle 4, the respective flow paths 4 b in the nozzle 4 separated by the partition wall 4 f are opposite to each other. A force in a direction (different from the discharge direction of the nozzle 4) is generated.

That is, in each flow path 4b of the nozzle 4, a force in the same direction and a force in the opposite direction with respect to the casting direction (arrow e direction) through which the molten metal 3 flows are applied to the molten metal 3 for each flow path 4b. It occurs alternately. For this reason, in the flow path 4b in which a force in the same direction as the flow direction (arrow e direction) of the forward flow f of the molten metal 3 is generated, the force becomes a suction force (pressing force) of the flow of the forward flow f. It generates forced flow of high-speed flow that is fast. In the flow path 4b in which a force in the direction opposite to the flow direction of the forward flow f of the molten metal 3 is generated, the forward flow f flows adjacent to the direction perpendicular to the casting direction (arrow b direction) by the force in the opposite direction. It is sucked into the flow path 4b side, and the forced flow of the backflow g is generated. The reverse flow g flows in the direction opposite to the casting direction, and then flows in the left-right direction (arrow h direction) and flows into the flow path 4b where the adjacent forward flow f flows.
For this reason, the molten metal 3 is discharged from the discharge port 4 c into the molten metal pool 6 between the cooling rolls 5, 5 as a stirring flow greatly disturbed by the fast flow f and the reverse flow g generated by forced flow. When the molten metal 3 is solidified in the unsolidified melted part between the cooling rolls 5 and 5, the flow of the molten metal 3 flows as a stirring flow, so even if the temperature of the solid-liquid coexistence temperature is wide, Then, a metal component such as magnesium that is difficult to solidify is stirred, and a solid-liquid coexistence state in which the solid phase metal and the liquid phase component are uniformly dispersed is obtained. In this state, the molten metal 3 is cooled by the cooling rolls 5 and 5 and solidified to prevent segregation in the ingot 7.

The molten metal 3 is rolled while being solidified by being heat-exchanged and cooled by being in surface contact with the cooling rolls 5 and 5 cooled by the roll cooling devices 51 and 51 between the cooling rolls 5 and 5. It is sent out in the casting direction in a state where it is formed in a shaped ingot 7.
In this case, as described above, the thin plate-shaped ingot 7 can produce a high-quality cast product because the molten metal 3 is solidified without segregation.
In addition, even when a eutectic alloy having a wide solid-liquid coexistence temperature range such as a high Mg alloy is continuously cast into a thin plate shape, segregation and cracks are prevented from occurring in the ingot 7, and various materials can be prevented. Can be cast in a stable state. For this reason, it is possible to manufacture a plate material of a high quality alloy material with no segregation and stable quality.

Next, examples will be described with reference mainly to Table 1 and FIG. In addition, the already demonstrated structure attaches | subjects the same code | symbol and abbreviate | omits the description.
Table 1 shows experimental data with a Ga-16 mass% In alloy whose flow was evaluated at room temperature using a nozzle according to an embodiment of the present invention, experimental data when an aluminum alloy molten metal was passed through an actual nozzle, and the like. It is a table | surface which shows. FIG. 7 is a view showing a high Mg alloy ingot continuously cast using a nozzle according to an embodiment of the present invention, wherein (a) is a perspective view of an ingot having a width of 300 mm and a thickness of 4 mm, and (b). FIG. 4 is an enlarged view of a G portion in (a).

In Example, in order to confirm whether the turbulent flow that is a stirring flow is generated in the molten metal 3, the continuous casting apparatus 1 using the nozzle 4 shown in FIG. Is a liquid metal having a specific gravity of 6.1 (g / cm ³ ) and a Ga-16 mass% In alloy (indium-gallium alloy melting point) Is melted at a flow rate (calculated value) of 19 (m / min) through the flow path 4b in the nozzle 4, and a current of 50 (A) is passed between the electrodes 41 and 42 to counter flow. A low temperature test in which a long ingot 7 having a width of 80 (mm) was continuously cast was actually conducted to confirm the occurrence of turbulent flow.

In this case, A: current 50 (A), S _s : cross-sectional area 20 × 10 ⁻⁶ (m ² ) of the flow path 4 b, T: magnetic flux density of the magnet 81 0.1 (T), W: width of the magnet 81 Is 10 (mm), P: the pitch of the magnet 81 is 20 (mm), and F: force (N / m ³ ), the force (magnetic force distribution) F generated in the flow path 4b is
(A / S _S ) × T × (W / P) = F
(50 (A) / 20 × 10 ⁻⁶ (m ² )) × 0.1 (T) × 10 (mm) / 20 (mm) = 1.25 × 10 ⁵ (N / m ³ )
It becomes.

Further, when L: length of the magnet 81 is 20 × 10 ⁻³ (m), F: force 1.25 × 10 ⁵ (N / m ³ ), ρ: density of the molten metal 2 is 2350 (kg / m ³ ), The speed v (m / s) at which the molten metal 3 moves only by magnetic force is
2L × (F / ρ) = v ²
= 2 × (20 × 10 ⁻³ (m)) × ((1.25 × 10 ⁵ (N / m ³ )) / 2350 (kg / m ³ ))
= (1.46 (m / s)) ²
It becomes.

Re: Reynolds number, t: flow path thickness in the nozzle 4 of 0.004 (m), v: speed of the molten metal 3 moving only by magnetic force 1.46 (m / s), ρ: density of the molten metal 2350 ( kg / m ³ ), μ: When the viscosity of the molten metal 3 is 0.0011 (Pa · s), the Reynolds number Re of the molten metal 3 flowing in the flow path 4b of the nozzle 4 is
Re = t × v × ρ / μ
= 0.004 (m) x 1.46 (m / s) x 2350 (kg / m ³ ) /0.0011 (Pa · s)
= 12500> 2500 (turbulent flow region)
It becomes. That is, since the Reynolds number Re is 12500 that is 2500 or more, which is a numerical value of the turbulent flow region where the fluid flow is turbulent, the molten metal 3 flowing in the nozzle 4 also becomes turbulent in terms of the calculated value.

Also, a magnet 81 having a magnetic flux density of 0.1 (T) is used, and a high-Mg alloy melt 3 with a specific gravity of 2.3 (g / cm ³ ) is supplied at a flow rate (calculated value) of 31 (m / min). Then, a flow of 50 (A) is sent between the electrodes 41 and 42 to flow in the flow path 4b of the nozzle 4 to generate a reverse flow, and the width of 300 (mm) as shown in FIG. The ingot 7 was continuously cast.
When the ingot 7 obtained in the test was photographed with X-rays from the upward direction of the arrow c, image data as shown in FIG. 7B was obtained. That is, the ingot 7 flows as a stirring flow from the inside of the nozzle 4 to the molten metal pool 6 by the stirring flow generating means 40, so that magnesium which has a low melting point and is difficult to solidify is stirred in a solid-liquid coexistence state. Since it was solidified, no segregation was generated as shown in FIG. The ingot 7 cast by the continuous casting apparatus 1 is solidified in the state of being stirred and flown so that the aluminum metal structure and the magnesium metal structure are mixed in a uniform state in the casting direction. Has been.

When the high-Mg alloy molten metal 3 is continuously cast with the continuous casting apparatus 100 using the conventional nozzle 400, it is uneven as a mountain range as shown by the thin line a in FIG. Compared with the metal structure, when continuous casting was performed with the continuous casting apparatus 1 using the nozzle 4 of the present invention, it was continuously formed in a gentle state as shown by a thin line d in FIG. 7B.
Thus, even when a thin plate such as a high Mg alloy having a wide solid-liquid coexisting temperature range is continuously cast in the continuous casting apparatus 1, segregation and cracks do not occur in the ingot 7, and a high quality cast product is obtained. Can be manufactured.

  The present invention is not limited to the above-described embodiment, and various modifications and changes can be made within the scope of the technical idea. The present invention extends to these modifications and changes. Of course.

  For example, in the above-described embodiment, the case where the aluminum alloy is cast by the continuous casting apparatus 1 using the nozzle 4 is described as an example. However, the temperature transmitted from the molten metal 3 to the magnet 81 is within the use limit temperature range of the magnet 81. If the molten metal 3 can be maintained and is a conductive metal, it can be similarly applied to other metals or alloys thereof. For this reason, the molten metal 3 may be other than an aluminum alloy.

As shown in FIG. 4, the stirring flow generating means 40 has been described in the case where the number of the magnets 81 of the magnet unit 8 is six and the number of the partition walls 4f is five in the width direction. is not. For example, the numbers of the magnets 81 and the partition walls 4f may be appropriately changed according to the width of the ingot 7 to be continuously cast.
The stirring flow generation means 40 may be provided with at least one set of magnets 81 and 81 of the N pole and the S pole above and below the nozzle 4 in the upper and lower magnet units 8 and 8. The number of sets of the magnets 81 may be appropriately changed according to the nozzle 4, the flow path 4b, the partition wall 4f, and the like.

That is, the stirring flow generating means 40 is arranged so that force is generated at least in the direction different for each adjacent flow path 4b, and with respect to the flow of the molten metal 3d that flows in the nozzle 4 toward the molten metal pool 6d. The flow may be disturbed by making the flow slow, stopping the flow, making it flow backward, generating a vortex, or changing the flow direction.
In this way, when the molten metal 3d is solidified, the flow of the molten metal 3d is disturbed, so that the solid phase metal having a high melting point and the liquid phase component having a lower melting point are mixed and solidified. It is possible to prevent segregation from occurring in the ingot 7.

It should be noted that a current that reverses the direction of current flow is supplied from the power supply drive control device 10 to the electrodes 41 and 42 in the width direction of the flow path 4b so that the upper and lower magnetic fields in the width direction of the nozzle 4 The force generated in the direction orthogonal to both the direction and the width direction in which the current flows may be alternately changed periodically.
Further, the inter-nozzle spacer 83 may be provided with a metal fin or the like for heat dissipation to improve heat dissipation.

DESCRIPTION OF SYMBOLS 1 Continuous casting apparatus 2 Dundish 3 Molten metal 4 Nozzle 4a Notch groove 4b Flow path 4e Outer surface 4f Partition wall 4g Communication port 4h, 4i Side wall 5 Cooling roll 6 Molten pool 7 Ingot 8 Magnet unit 9 Magnet cooling apparatus 10 Power supply drive control apparatus 40 Stirring flow generating means 41, 42 Electrode 81 Magnet 82 Case 83 Inter-nozzle spacer 84 Inter-magnet spacer 85 Air passage 91 Fan 92 Fan motor

Claims (15)

In the continuous casting method for producing a plate-shaped ingot by rolling the molten metal discharged from the nozzle to the molten metal pool with a pair of cooling rolls arranged at a predetermined interval,
An electromagnetic force is generated in the molten metal in the nozzle by using a permanent magnet of a stirring flow generating means , a forced flow is generated using the electromagnetic force, and the molten metal flowing in the nozzle is converted into the pair of cooling rolls. A continuous casting method characterized by discharging from the discharge port of the nozzle disposed so as to be inserted between the molten metal pool and solidifying while stirring the unsolidified molten portion between the pair of cooling rolls. The stirring flow generating means is provided with electrodes on the left and right side walls of the flow path in the nozzle, and between the magnetic fields of the permanent magnets provided on the upper and lower sides of the nozzle , via the molten metal that is a conductor. The continuous casting method according to claim 1, wherein an electromagnetic force is generated by passing a current between them to generate a forced flow in the nozzle. The Reynolds number of the molten metal flowing in the nozzle, the continuous casting method according to claim 1 or claim 2, characterized in that at 2500 or higher. The stirring flow generating means generates a magnetic field in the vertical direction in the nozzle by magnets provided alternately in the width direction outside the nozzle,
A current flows in the width direction of the nozzle through the melt flowing in the nozzle, and the opposite direction to the melt for each flow path divided by a plurality of partition walls arranged in parallel in the width direction at a predetermined interval in the nozzle 2. The continuous casting method according to claim 1, wherein segregation is prevented from occurring in the ingot by generating the force. 5. The continuous casting method according to claim 4 , wherein magnesium is contained in the molten metal component and the occurrence of segregation of magnesium is prevented by the stirring . In a nozzle used in a continuous casting apparatus for producing a plate-shaped ingot by rolling a molten metal from a dundish with a pair of cooling rolls arranged at a predetermined interval,
The nozzle supplies the molten metal from the dandish between the cooling rolls, and allows current to flow between the electrodes provided on the left and right side walls of the flow path in the nozzle via the molten metal, and is divided by a partition wall. And a stirring flow generating means for forcibly flowing the molten metal by generating a force in the opposite direction to the molten metal for each flow path. The partition wall is provided in the flow path in the nozzle along the direction in which the molten metal is discharged, and a plurality of the partition walls are arranged in parallel in the width direction of the flow path at predetermined intervals.
The nozzle comprises stirring flow generating means for disturbing the flow of the molten metal before the molten metal comes out of the nozzle into the molten metal pool,
A communication port formed at each partition wall position on a straight line along the width direction of the flow path,
The nozzle according to claim 6, comprising: The stirring flow generating means includes electrodes provided on left and right side walls in the flow channel at a position on a straight line where the communication port is formed;
A plurality of magnets provided on the upper and lower outer sides of the nozzle so as to generate a magnetic field in the vertical direction;
The nozzle according to claim 7, comprising:   The nozzle according to claim 8, wherein the plurality of magnets are permanent magnets in which different magnetic poles are alternately arranged along a straight line on which the communication port is formed. On the upper and lower outer surfaces of the nozzle, notch grooves respectively extending in the width direction,
A magnet unit disposed in the cutout groove and containing the plurality of magnets;
The nozzle according to claim 8, wherein the nozzle is provided.   The nozzle according to claim 8 or 9, further comprising a magnet cooling device that cools the plurality of magnets.   The nozzle according to claim 11, wherein the magnet cooling device includes an air passage that is provided in the magnet unit and flows air for air-cooling the magnet unit.   The nozzle according to claim 10, wherein the magnet unit includes an inter-nozzle spacer made of a heat insulating material and interposed between the notch groove and each magnet. The magnet unit includes an inter-magnet spacer interposed between the magnets,
A case made of a nonmagnetic metal that houses the inter-magnet spacer and the plurality of magnets;
The nozzle according to claim 10, wherein the nozzle is provided.   The nozzle according to any one of claims 8 to 14, wherein each magnet is made of a rare earth magnet or an alnico magnet.

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