JP2000079451A - Tundish and production of rare earth element-containing alloy using this tundish - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tundish, in which the tapping quantity of melt onto a cooling roll is easily kept constant and a casting apparatus does not come to break even the case of clogging of the melt and the maintenance is easily executed. SOLUTION: The tundish 4A is constituted by forming as a box shape with a bottom plate 41 integrally forming a weir 52 and a melt tapping plate 53 at the downstream end side, side plates 42 at both sides, a front plate 43 forming a cover 59 for the melt tapping plate 53 at the lower half part so as to form a nozzle-state molten metal tapping passage 51 and a rear plate 44, and supporting an inclined receiving plate 46 with a supporting plate 45 arranged so as to be in contact with the inside of the side plates 42. The molten metal tapped onto the upper end part of the inclined receiving plate 46, is made to flow down on the inclined receiving plate 46 and dropped to the rear end part of the bottom plate 41 and formed as the constant depth with the weir 52 and made to flow to almost the whole length of the bottom plate 41 to rectify the molten metal stream and tapped onto the cooling roll 5 from the molten metal tapping passage 51 while thermally insulated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tundish for pouring molten metal melted in a metal melting furnace onto the surface of a cooling roll, and more particularly, to a uniform and safe pouring of molten metal. In addition, it relates to a tundish that is easy to maintain.

[0002]

2. Description of the Related Art Various methods have been proposed for tundishes in order to uniformly pour molten metal melted in a metal melting furnace onto the surface of a cooling roll.

(Conventional Example 1) FIG. 9 is Japanese Patent Application Laid-Open No. Hei 8-22964.
1 is a schematic diagram showing a tundish 103, a quenching roll 105, and others disclosed in Japanese Patent Publication No. A high-frequency melting furnace 102 and a tundish 103 having a nozzle 104 at the tip in a closed vessel 101 in a vacuum or inert gas atmosphere, a quenching roll 105 adjacent thereto, and a scraper 106 in contact with the surface of the quenching roll 105 ,
And a slab recovery container 107. And
The nozzle 104 at the tip of the tundish 103 is disposed so as to face an angle range of θ = 30 ° to 90 ° with respect to a line connecting the uppermost portion 105a of the quenching roll 105 and the center point 105b. Tip and quenching roll 1
The gap length with the surface of No. 05 is 0.01 mm to 3.0 mm.
Is set to

[0004] The molten metal 1 in the tundish 103
08 is poured from the nozzle 104 to the quenching roll 105, if the angle θ of the nozzle 104 is less than 30 °, the slab is insufficiently cooled.
Nozzle clogging is likely to occur due to solidification of the molten metal at the nozzle portion by sliding on the surface of the nozzle 05. The gap length between the tip of the nozzle 104 and the surface of the quenching roll 105 is 0.01 mm.
If the diameter is less than 3.0 mm, the nozzle 104 comes into contact with the surface of the quenching roll 105 to easily generate a flaw.
It is described that hot water leaks from between the surface 4 and the surface of the quenching roll 105.

(Conventional Example 2) FIG.
13 is a perspective view of a tundish 110 disclosed in Japanese Patent Publication No. 13; This tundish 110 has been proposed as a conventional tundish having a nozzle at the tip end because the nozzle is easily clogged. However, a gently inclined bottom surface 111 through which an alloy melt flows in the direction of the arrow, and a side surface thereof 112 to keep alloy melt from flowing out
a, 112b, and a dam plate 113 provided with two flow paths 113a, 113b of an alloy melt provided separately.

That is, the flowing alloy melt 114
The hot water is temporarily stored on the bottom surface 111 side of the weir plate 113, the flow velocity is delayed, and the hot water is divided and flows out from the flow channels 113a and 113b.
Are supplied at a substantially uniform flow rate within the width of the rotating roll.

[0007]

In general, a tundish having a weir or a pouring nozzle at the tip end can easily maintain a constant amount of pouring into a cooling roll, but clogging occurs due to a decrease in the temperature of the molten metal. There is a problem that high-temperature molten metal overflows easily from the tundish, and in an extreme case, the casting apparatus may be damaged. On the other hand, in a tundish without a weir or nozzle, clogging does not occur, but the amount of molten metal poured into the cooling roll tends to fluctuate. In addition, conventional tundishes are manufactured as an integrally molded product of ceramics.For example, if the tundish is partially damaged due to thermal shock, it is repaired in a process of applying a cement and heating and curing, so it takes a long time to repair Essentially, it lowers the operation rate of the device. In addition, the tip of the tundish is installed close to the cooling roll in order to reduce the thickness of the molten metal on the cooling roll as much as possible in order to obtain the quenching effect. It is easy to replace the cooling roll, and it takes a long time to reduce the operating rate of the casting apparatus.

The present invention has been made in view of the above-mentioned problems, and is a tundish capable of maintaining a uniform amount of molten metal poured into a cooling roll. Even if clogging occurs, the tundish does not cause damage to a casting apparatus. Is to provide a tundish that can be repaired in a short time.

[0009]

The above object is achieved by the features of claim 1 and the dependent claims. To explain the solution, the tundish of the present invention is supplied from a crucible. The molten metal is received by the inclined receiving plate to stop the momentum of the molten metal, and the molten metal is supplied not only near the center but also to both ends. Further, the flow of the molten metal is made to have a shape that can be as long as possible, and the shape of the molten metal is made to be as small as possible to achieve rectification of the molten metal. Further, the shape is such that the temperature decrease due to radiation can be prevented as much as possible.

Further, the tundish of the present invention is constituted by combining a plurality of types of plate members made of ceramics having a simple shape, thereby facilitating disassembly and assembly, and enabling partial replacement of each plate member.

In the tundish of the present invention, the amount of molten metal in the tundish is constantly monitored. When the amount exceeds a predetermined amount, the tapping of the metal from the metal melting furnace to the tundish is forcibly stopped. An overflow molten metal receiver is provided in case a weir or pouring channel for controlling the amount of hot water is blocked and the tundish overflows with molten metal. Further, the tundish is movably installed in order to facilitate the work, for example, when replacing the cooling roll.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The tundish of the present invention receives molten metal supplied from a crucible by an inclined receiving plate, thereby stopping the momentum of the molten metal and supplying the molten metal not only near the center but also to both ends. Furthermore, a weir is provided at the front end of the bottom surface, and the shape of the flow path of the molten metal is made as long as possible, and when the molten metal is dropped, the shape of the molten metal is made as small as possible. Rectification. Further, the thickness of the tundish is increased to enhance the heat retaining property, or a cover is provided in the flow path of the molten metal so as to prevent the temperature of the molten metal from being lowered by radiation as much as possible. The shape of the tundish is not particularly limited as long as it is such a tundish.

The tundish of the present invention is manufactured by assembling a plurality of types of ceramic plates having a simple shape so that the tundish can be easily assembled and disassembled. It is set according to the shape.

Further, in the tundish of the present invention, an overflow molten metal receiver is provided in case a molten metal overflows from the tundish due to a blockage of a pouring path to a weir or a cooling roll for controlling a constant amount of molten metal. At the same time, the amount of the molten metal in the tundish is constantly monitored, and when the amount exceeds a predetermined amount, the tapping of the molten metal from the melting furnace to the tundish is forcibly stopped, but the shape and location of the overflow molten metal receiver are not particularly limited, Further, the amount of molten metal in the tundish may be monitored by weight, or the height of the molten metal surface may be monitored, for example, by the time required for reflection of ultrasonic waves.

Further, when replacing the cooling roll, etc.,
To facilitate the work, the tundish is installed so that it can be separated from the chill roll. In order to separate them, they may be moved sideways or upward.

Hereinafter, the tundish of the present invention will be described in detail with reference to the drawings.

[0017]

FIG. 1 is a partially cutaway side view showing a tundish 4A of an embodiment installed in a metal casting apparatus, together with a metal induction heating type melting furnace 2 and a cooling roll 5.
FIG. 2 is a plan view corresponding to FIG. That is, the molten metal in the induction heating type melting furnace 2 is discharged to the tundish 4A, and the molten metal is poured from the tundish 4A to the surface of the cooling roll 5 rotating forward, and cooled to form a strip-shaped quenched slab. A scraper 6 is attached to a surface on the downstream side of the cooling roll 5, and the quenched slab is separated from the cooling roll 5.

The induction heating type melting furnace 2 has a rotating shaft 31 of the column 3.
And is rotatable from a position shown by a solid line to a position shown by a two-dot chain line by a hydraulic cylinder not shown. Then, the molten metal of the metal melted in the melting furnace 2 is quantitatively supplied from the tap hole 22 to the tundish 4A.

FIG. 3 is a plan view of the tundish 4A, FIG. 4 is a sectional view taken along the line [4]-[4] in FIG. 3, and FIG. 5 is a sectional view taken along the line [5]-[5] in FIG. It is an arrow view. At this time, the inclined receiving plate is arranged so that the included angle α is 90 ° or less (preferably 20 to 80 °) so that the molten metal does not fly out of the tundish and leak. The included angle in this case was the angle at which the molten metal collides with the receiving plate. That is, α
Is the angle at which the molten metal supplied from the crucible collides with the receiving plate. Referring to FIGS. 3 to 5, tundish 4 </ b> A has bottom plate 41 integrally formed with pouring plate 53 on the downstream end side, side plates 42 on both sides, and lower half portion serves as cover 59 of pouring plate 53. Plate 4 as a front wall forming a nozzle-like pouring channel 51
3, and a rear plate 44 as a rear wall is formed in a box shape, and is constituted by supporting the inclined receiving plate 46 on both side support plates 45 provided in contact with the inside of the side plate 42. A reinforcing plate 47 is attached below the bottom plate 41, and a reinforcing plate 48 is attached behind the rear plate 44. These can be removed and replaced independently. The whole of the tundish 4A assembling them is fixed in a steel outer frame 49 shown in FIG.

Referring to FIGS. 4 and 5, pouring plate 53 integrally formed on the downstream end side of bottom plate 41 has a lower surface from bottom plate 41 so as to maintain a constant pouring amount. Four flow guide plates 54 are formed as portions that exceed the slightly raised weirs 52 and further protrude from the surface of the pouring plate 53 by dividing the width of the pouring plate 53 into approximately four parts. Dividing channel 55
Is formed, and the pouring path 5 is formed together with the cover 59 described above.
1 is formed. 4 and 5, three flow guide plates 54 are shown, but up to seven flow guide plates 54 may be provided.
The book is formed.

With the above-described configuration, the molten metal poured from the melting furnace 2 to the upper part of the inclined receiving plate 46 flows down the inclined receiving plate 46 and drops to a rear end portion of the bottom plate 41 to form a turbulent flow. Is suppressed as much as possible, then the thickness of the molten metal is maintained by the weir 52 and flows along substantially the entire length of the bottom plate 41, and further flows along the flow guide plate 54 in the pouring plate 53. The stream is rectified and poured into the cooling roll 5. In addition, in the pouring path 51, the flow path guide plate 54
As a result, the molten metal flows through the branch channel 55 while maintaining its thickness, so that even when the molten metal reaches the cooling roll 5, the molten metal is poured without narrowing. The inclined receiving plate 46 having a high temperature is provided above the molten metal flowing on the surface of the bottom plate 41.
Therefore, a decrease in temperature due to radiation of the molten metal is prevented. The temperature of the molten metal flowing through the pouring plate 53 is prevented from lowering by the cover 59.

As described above, the clogging of the molten metal in the tundish 4A is prevented. However, since the clogging of the molten metal tends to easily occur in a weir or a nozzle provided in the tundish, the tundish 4A of the embodiment is generally used. Also, a mechanism is provided to prevent clogging near the pouring plate 53, particularly near the weir 52. That is, referring to FIG. 2, the load cells housed in the covers 64 on both sides of the tundish 4A cause the tundish 4A.
The total weight of the molten metal and the molten metal is constantly monitored, and when the weight exceeds a predetermined value, the tapping of the molten metal from the furnace 2 to the tundish 4A is forcibly stopped. Also,
When clogging occurs in the tundish 4A, the molten metal overflowing from the tundish 4A is guided to the molten metal receiver 63 from the discharge port 62 through the grooves 61 on both sides, and is prevented from scattering to other locations.

The tundish 4A is mounted on the base 71
Above, it is supported by a height-adjustable column 72, so that the height from the surface of the cooling roll 5 to the tip of the pouring channel 51 can be adjusted. A pair of wheels 73 pivotally supported on both sides of the lower end of the support column 72,
The tundish 4A can be moved to the side by the traveling rail 74 fixed to 1.

The tundish 4A of the embodiment is configured as described above, and its operation will now be described.

That is, referring to FIGS. 3 to 5, the molten metal from the melting furnace 2 is poured into the front end of the inclined receiving plate 46, flows down, and falls to the upstream portion of the bottom plate 41 at a low drop. By changing the direction and flowing along the substantially entire length of the bottom plate 41, and then flowing along the pouring path 51 along the flow path guide plate 54,
The flow is rectified to the cooling roll 5 and poured into the cooling roll 5. The molten metal flowing on the bottom plate 41 is prevented from lowering in temperature due to radiation by the upper inclined plate 46 having a high temperature,
The temperature of the molten metal flowing through the pouring channel 51 is also prevented from lowering by the cover 59.

The tundish 4A is filled with a pouring plate 53.
Plate 41, side plates 42 on both sides, pouring plate 5 provided integrally with
A front plate 43, a rear plate 44 integrally provided with a third cover 59,
The plate material such as the support plate 45, the inclined receiving plate 46, and the reinforcing plates 47 and 48 is assembled as an element, and it is easy to disassemble the tundish 4A into those plate materials. Even if it is damaged by thermal shock, it is possible to replace only that part, and repair is extremely easy as compared with the case where the conventional integrally molded tundish is partially damaged.

Further, referring to FIG. 2, even if the molten metal is clogged in tundish 4A, the load cells contained in covers 64 on both sides constantly monitor the total weight of tundish 4A and molten metal. When the weight exceeds a predetermined value, the tapping from the metal melting furnace 2 to the tundish 4A is forcibly stopped. Also, even if the molten metal overflows from the tundish 4A, it is guided to the molten metal receiver 63 from the outlet 62 through the grooves 61 on both sides of the tundish 4A and is accommodated. An accident such as damage to the casting device is prevented.

In addition, the column 72 for supporting the tundish 4A can be moved laterally by two pairs of wheels 73 supported on both sides of the lower end thereof and a traveling rail 74 fixed to the gantry 71. Therefore, the tundish 4A can be moved to the side when the cooling roll 5 is replaced or when the tundish 4A is preheated, for example. Therefore, the replacement work of the cooling roll 5 and the like are completed in a short time.

(Specific Example) Using the tundish of the present invention, Nd, Dy, electrolytic iron, Co, ferroboron, Al and Cu are used as starting materials, and the weight ratio is 30Nd-1D.
y-BAL. Fe-4Co-1.1B-0.3Al-
After compounding with a composition of 0.2Cu, an alloy ribbon was produced by a strip casting method. Table 1 shows the relationship between the angle between the receiving plate and the molten metal and the weight% of the scattered amount of molten metal with respect to the amount of molten metal and the uniformity of distribution of molten metal to the slits.

[Table 1]

The tundish 4A according to the embodiment of the present invention is constructed and operates as described above. Of course, the present invention is not limited to this, and various modifications are possible based on the technical idea of the present invention. It is.

For example, in the present embodiment, the inclined receiving plate 46 in the tundish 4 is formed in a flat plate shape, but it may be formed as a curved plate having a gentle downward convexity. Further, in the present embodiment, a device for heating the tundish 4A is not provided, but a device for heating the pouring path 51, which is likely to cause clogging of the molten metal, from outside, for example, a device for irradiating infrared rays. May be added.

In the present embodiment, the inclined receiving plate 4
Although the tundish 4A having the pouring path 51 with the cover 6 and the cover 59 has been described, it is also possible to use a tundish of a shape other than this. For example, FIG. 6 is a cutaway side view of a tundish 4B according to a first modification of the present invention, and is a view corresponding to FIG. 4 of the tundish 4A. The tundish 4B is formed by assembling a thick bottom plate 81, both side plates 82, a front plate 83, and a rear plate 84 so that the temperature is not easily lowered by heat radiation. At the front end of the bottom plate 81, the surface thereof is inclined upward to form a weir 85 for the molten metal, and the front end surface of the bottom plate 81 is inclined downward to form a flow path 86.
And The lower end of the front plate 83 is a weir 85 of the bottom plate 81.
And a tap hole 87 is provided between the lower end thereof and the surface of the bottom plate 81, and a front plate 83 is provided.
A discharge port 88 is formed above the tap hole 87 when the tap port 87 is clogged.
This prevents the temperature drop due to the radiation of the molten metal near the tap 87. The molten metal poured into the tundish 4B from the metal melting furnace 2 is made to have a constant thickness by a weir 85, and is poured from the outlet 87 into the cooling roll 5 through the pouring path 86 as rectification.

FIG. 7 shows a tundish 4 of the second modification.
It is a fracture | rupture side view of C. Since the shape is the same as that of the tundish 4B of the first modification in FIG. 6, the same reference numerals are given to the same components, and the description thereof will be omitted. The difference from the tundish 4B of the first modification is that the front plate 8
3 is provided with a downwardly downwardly inclined portion slightly downward from the eaves portion immediately before the outlet 88 to serve as a heat insulating cover 89 b for the flow path 86 on the front end surface of the bottom plate 81. The temperature of the molten metal poured from the tap hole 87 to the cooling roll 5 is prevented from dropping by the heat retaining cover 89b, and clogging due to the drop in the temperature of the molten metal in the tap hole 87 and the flow path 86 is prevented.

FIG. 8 shows a tundish 4 of the third modification.
It is a fracture | rupture side view of D. The tundish 4D is formed by assembling a bottom plate 91, both side plates 92, and a rear plate 94. At the front end of the bottom plate 91, a weir 98 of the molten metal is provided,
The front end face has a flow path inclined forward and downward, and a flow path guide plate 99 is provided similarly to the flow path guide plate 54 in the tundish 4A of the embodiment. The front plate does not exist, but as an alternative, the tundish 4D extends from the upper end of the front end to a position close to the bottom surface of the rear end.
The inclined receiving plate 96 having a downwardly inclined width is provided, and a heat retaining plate 97 is provided from the lower end of the inclined receiving plate 96 to a position in front of the weir 98 in parallel with the bottom plate 91. Although not shown, the inclined receiving plate 96 and the heat retaining plate 97 are supported by a supporting plate provided in contact with the inside of the both side plates 92.

The molten metal poured from the metal melting furnace 2 to the front end of the inclined receiving plate 96 flows down the inclined receiving plate 96 and flows from the rear end to the bottom plate 9.
1 falls at a low drop to the rear end, changes direction and flows.
The molten metal has a constant thickness by the weir 98, flows almost the entire length of the bottom surface 91, is rectified, flows over the weir 98, is guided to the flow path guide plate 99, and is poured into the cooling roll 5. At this time, the molten metal flowing on the bottom surface 91 is
The temperature of the molten metal poured over the weir 98 is prevented by the front end of the heat retaining plate 97.

In this embodiment, the total weight of the tundish 4 and the molten metal inside the tundish 4A is measured by the load cell in order to monitor the amount of the molten metal in the tundish 4A. The amount of molten metal may be monitored. For example, transmitting ultrasonic waves toward the molten metal surface,
The liquid level of the molten metal may be monitored according to the time until the reflected wave is received. By irradiating the surface of the molten metal with light, the height of the liquid level of the molten metal can be similarly monitored from the magnitude of the reflection intensity.

In the present embodiment, the tundish 4A is installed so as to be movable laterally in order to facilitate the work such as replacement of the cooling roll 5, but for example, the tundish 4A is raised by a hydraulic cylinder. Is also good.

[0038]

The present invention is embodied in the form described above, and has the following effects.

By providing an inclined receiving plate, lengthening the flow path of the molten metal and providing a weir, and making the necessary head as small as possible, the molten metal is poured into the cooling roll in a state where the molten metal is rectified from the tundish. As a result, the width and thickness of the molten metal on the cooling roll can be easily maintained at a constant value, and thus the molten metal can be easily cooled uniformly. Further, the thickness of the tundish may be increased as a whole to enhance the heat retention, or, for example,
As in the upper inclined receiving plate 46, a high-temperature cover is provided above the flow path of the molten metal to prevent the temperature from being lowered due to the radiation of the molten metal. Clogging of the molten metal in the dish hardly occurs.

Further, since the tundish is formed by assembling a plurality of types of plate materials having relatively simple shapes, even if the tundish is partially damaged by, for example, a thermal shock, only the plate material at the corresponding portion is damaged. Can be restored in a short time by replacing the cooling roll with eaves, and when replacing the cooling roll with eaves, the tundish can be separated from the cooling roll. A reduction in the operating rate of the casting device is avoided.

The amount of the molten metal in the tundish is constantly monitored, and when the amount of the molten metal exceeds a predetermined amount, the tapping of the metal from the melting furnace to the tundish is stopped. Since the overflow molten metal receiver is provided in preparation for dispensing, it is possible to prevent an accident that high-temperature molten metal overflows and damages the casting apparatus.

[Brief description of the drawings]

FIG. 1 is a partially broken side view showing a tundish installed in a metal casting apparatus together with a heating melting furnace and a cooling roll.

FIG. 2 is a plan view corresponding to FIG.

FIG. 3 is a plan view of the tundish of the embodiment.

FIG. 4 is a sectional view taken along the line [4]-[4] in FIG.

FIG. 5 is a view in the direction of arrows [5]-[5] in FIG. 4;

FIG. 6 is a cutaway side view of a tundish of Modification 1.

FIG. 7 is a cutaway side view of a tundish of Modification 2.

FIG. 8 is a cutaway side view of a tundish of Modification Example 3.

FIG. 9 is a partially broken side view of the tundish of Conventional Example 1.

FIG. 10 is a perspective view of a tundish of Conventional Example 2.

[Explanation of symbols]

 2 Induction Heating Melting Furnace 3 Support 4A Tundish 4B Tundish 4C Tundish 4D Tundish 5 Cooling Roll 6 Scraper 41 Bottom Plate 42 Side Plate 43 Front Plate 44 Rear Plate 45 Support Plate 46 Inclined Plate 47 Reinforcement Plate 48 Reinforcement Plate 49 Outside Frame 51 Pouring channel 52 Weir 53 Pouring plate 54 Flow guide plate 55 Dividing channel 61 Groove 62 Discharge port 63 Overflow molten metal receiver 64 Cover 72 Post 73 Wheel 74 Traveling rail

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Koji Sato, Inventor 2-5-1-5 Kitafu, Takefu-shi, Fukui Shin-Etsu Kagaku Kogyo Co., Ltd. Magnetic Materials Research Laboratory (72) Inventor Takahiro Hashimoto 2-1-1 Kitafu, Takefu-shi, Fukui No.5 Shin-Etsu Kagaku Kogyo Co., Ltd. Magnetic Materials Research Laboratory (72) Inventor Masaki Kasashima 2-5-1 Kitafu, Takefu-shi, Fukui Prefecture Shin-Etsu Kagaku Kogyo Co., Ltd. Magnetic Materials Research Laboratory

Claims (15)

[Claims] 1. A tundish for pouring a molten metal melted in a melting furnace to a cooling roll, wherein an inclined receiving plate for receiving the molten metal supplied from a crucible to the tundish, and a horizontally elongated slit-shaped bottom surface in the tundish. Characterized in that a tap hole or a nozzle-like pouring channel is provided. 2. The tundish according to claim 1, wherein the angle between the molten metal flowing out of the crucible and the inclined receiving plate receiving the molten metal is set to be 90 ° or less. 3. A tundish in which a weir for molten metal is provided integrally with the tap hole or the pouring channel, and the molten metal is rectified by a relatively long flow path on the bottom surface of the tundish,
3. The tundish according to claim 1, which is poured into a cooling roll. 4. The weir is formed so that the surface of the front end of the bottom surface is slightly inclined upward toward the downstream side, the front end surface of the bottom surface is formed as a downwardly inclined flow path, and the tundish is a box. The lower end of the front wall having a shape and a box shape is located in the middle of the inclination, and the tap hole is formed between the lower end and the bottom surface. In addition, when the tap port is closed, 4. The tundish according to claim 1, wherein a discharge port of the molten metal is formed on the front wall above the tap hole. 5. 5. The flow passage according to claim 1, wherein a drooping portion of the front wall is formed so as to be inclined forward from above the discharge port to serve as a cover for the flow path on the front end face. Tundish. 6. A tundish having a box shape, and an inclined receiving plate having a box-shaped width inclined downward from an upper end portion on a front end side of the box shape toward a rear end side thereof is provided to a height close to the bottom surface. The head between the flow path on the bottom surface and the flow path on the bottom surface is reduced, and the weir is provided at a front end of the bottom surface, and the front end surface of the weir is a flow path inclined downward. 4. The tundish according to claim 3, wherein a cover for the flow path on the bottom surface is provided from a lower end of the inclined receiving plate to a position parallel to the bottom surface and beyond the weir. 7. The tundish according to claim 3, wherein the weir is divided by a plurality of flow guide plates equally dividing its width. 8. A tundish having a box shape, and an inclined receiving plate having a box-shaped width inclined downward from an upper end portion on a front end side of the box shape toward a rear end side thereof is provided to a height close to the bottom surface. The head between the flow channel on the bottom surface and the flow path on the bottom surface is reduced, and the weir is provided at the front end of the bottom surface, and a pouring channel inclined downward and forward is provided following the weir. 4. The tundish according to claim 3, wherein an extension is formed so as to be inclined downward and forward from a lower end of the box-shaped front wall to serve as a cover for the pouring channel. 9. The tundish according to claim 8, wherein the weir and the pouring channel are divided by a plurality of flow path guide plates equally dividing their width. 10. The tundish according to claim 1, wherein the entire tundish is constructed by assembling plate members having a relatively simple shape. 11. The amount of the molten metal in the tundish is constantly monitored, and when the amount of the molten metal exceeds a predetermined amount, supply of the molten metal from the metal melting furnace to the tundish is stopped. A tundish according to any one of claims 1 to 12. 12. The tundish according to claim 1, wherein the monitoring of the amount of the molten metal is performed by measuring a total weight of the tundish and the molten metal. 13. The tundish according to claim 1, wherein an overflow molten metal receiver is provided around the tundish in case the molten metal overflows from the tundish. 14. The tundish according to claim 1, wherein the tundish is installed so as to be separated from the cooling roll when the cooling roll is replaced or the like. 15. A method for producing a rare earth element-containing alloy using the tundish according to claim 1. Description: