JPS6340630B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a molten metal supply device for manufacturing amorphous metal, and particularly to a device for supplying molten metal to a tundish.

(Prior Art) In recent years, amorphous metals having good magnetic properties have attracted attention. This amorphous metal is produced, for example, by continuously jetting and supplying molten metal stored in a tundish through a microgap slit in a nozzle tip onto the circumferential surface of a cooling roll rotating at high speed, and rapidly solidifying the metal. The amorphous metal (product) manufactured by this method has a thickness of 25 μm.
It is a very thin band. Therefore, the amount of molten metal supplied to the circumferential surface of the cooling roll is much smaller than the amount of molten metal supplied from the tundish to the mold in the case of normal continuous casting. It is necessary to stabilize the amount of ejection from the small gap slit of the nozzle by adjusting the height of the surface. Therefore, there is a strong demand for a device that can finely adjust and supply molten metal from a ladle or the like to a tundish.

Conventionally, an apparatus as shown in FIG. 1 has been known as a molten metal supply apparatus for manufacturing this amorphous metal. That is, the molten metal M is supplied from the ladle 1 to the tundish 4 through the sliding nozzle 2 and the long nozzle 3, and the stopper 5 is operated while keeping the height of the molten metal level in the tundish 4 constant to melt the metal at a constant flow rate. Metal M through nozzle 6
In this device, the liquid is ejected from a slit 7 onto the surrounding surface of a cooling roll 8 that rotates at high speed.

(Problems to be Solved by the Invention) However, in this device, the molten metal M is supplied from the ladle 1 to the tundish 4 by operating the sliding nozzle 2. In order to supplement the molten metal ejected from the nozzle slit 7 from the ladle 1 to the tundish 4, it is necessary to make the hole diameter of the sliding nozzle 2 considerably small.
As a result, the hole of the sliding nozzle 2 becomes clogged, and there is a very high possibility that the supply of molten metal to the tundish 4 becomes impossible in a short period of time.

For example, the height of the hot water level in ladle 1 at the start of pouring H ₁
= 20 cm, the height H ₂ from the hot water surface of the tundish 4 to the bottom of the ladle 1 = 60 cm, the length of the nozzle slit 7 is 15 cm, the width is 0.06 cm, and the molten metal discharge rate from the nozzle slit 7 is 150 cm/sec. At this time, in order to supplement the molten metal M from the ladle 1 by the amount discharged from the nozzle slit 7, the plate hole diameter of the sliding nozzle 2 must be approximately 7 mm. Compared to the plate hole diameter of a normal sliding nozzle 2, which is about 70 mm, this is a much smaller value, and is inappropriate for feeding from the ladle 1 to the tundish 4 due to blockage. There is a very high possibility that the supply of molten metal M will become impossible in a short period of time, and it is not suitable for supplying a small amount of molten metal.

In addition, as other devices, for example, Japanese Patent Application Laid-open No.
As shown in No. 10448, the ladle and mold are connected with a fire-resistant U-shaped tube, the ladle is placed in a sealed container, and the surface of the molten metal in the ladle is pressurized with gas, allowing the molten metal to pass through the U-shaped tube and into the tundish. The ladle is connected to the tundish with a fire-resistant U-shaped tube equipped with a vacuum device or a vacuum device, and the molten metal in the ladle is pumped through the U-shaped tube by the vacuum device. There is also known a device that suctions the liquid through a tube and transfers it to a tandice.

However, these devices require a large-capacity airtight container that allows the ladle to be taken in and out, a vacuum device,
It requires a highly airtight, fire-resistant U-shaped pipe, etc., which places a heavy burden on the equipment, and while supplying molten metal,
For example, in the event of a sudden accident such as a hot water leak, it is difficult to respond quickly.

Still other devices include those using electromagnetic pumps, but these are quite expensive and require large equipment costs, making them impractical.

An object of the present invention is to provide a molten metal feeding device for manufacturing amorphous metal, which does not have the drawbacks of the conventional feeding devices, is low cost, and allows for the feeding and fine adjustment of a small amount of molten metal. It is something.

(Means for Solving the Problems) The molten metal supply device of the present invention includes an intermediate container adjacent to a tundish, a bubble pump for feeding molten metal from the intermediate container to the tundish, and a flow rate adjustment valve provided in a bubble gas supply pipe. It is made up of.

In the bubble pump, the pump body is suspended between an intermediate container and a tundish, and bubbles are supplied into the pump body from a bubble gas supply pipe.

(Function) Molten metal is poured into the intermediate container from a ladle, and the poured molten metal is supplied to the tundish by a bubble pump. The amount of bubble gas supplied to the pump body is adjusted by a bubble gas flow rate adjustment valve provided in the bubble gas supply pipe, thereby adjusting the amount of molten metal supplied from the intermediate container to the tundish. As a result, the head of the molten metal in the tundish, that is, the height of the liquid level, is finely adjusted and the amount of molten metal supplied from the nozzle to the surface of the cooling body is stabilized.

(Examples) Example 1 FIGS. 2 and 3 show an example of an apparatus for implementing the present invention.

In this drawing, the ladle 1, tundish 4, stopper 5, nozzle 6, and cooling roll 8 are the same as in FIG. Reference numerals are given and explanations are omitted.

A box-shaped intermediate container 11 made of refractory material is arranged adjacent to the tundish. Molten metal M is supplied to the intermediate container 11 from the ladle 1.

A pump body 22 of a bubble pump 21 is stretched between the tundish 4 and the intermediate container 11. The pump body 22 is made of a refractory material, and includes a liquid lift pipe 23 that vertically enters the intermediate container 11, a discharge pipe 25 that vertically enters the tundish 4, and connects the top of the liquid lift pipe 23 and the top of the discharge pipe 25. It consists of a connecting pipe 27 and has a U-shape as a whole. The communication pipe 27 is provided with an exhaust hole 29 that opens upward.

The material of the pump body 22 is
If the entire structure cannot be preheated sufficiently, a material with high thermal shock resistance is required. That is, in this case, a sharp temperature gradient is formed on the tube wall at the initial stage of operation, and a large thermal stress is generated. If this thermal stress exceeds the material strength of the pump body 22, cracks will occur in the pump body 22, resulting in a water leakage accident. In order to alleviate thermal stress, it is necessary to use a material with low thermal expansion, low elastic modulus, and high thermal conductivity. Typical examples of materials with low thermal expansion are fused silica and aluminum titanate, and examples of materials with low elastic modulus and high thermal conductivity are Al ₂ O ₃
-C quality can be mentioned. Therefore, by forming the pump body 22 with these materials, the occurrence of cracks due to thermal stress can be reduced.

A bubble inlet 31 of the bubble pump 21 is provided at the bottom of the intermediate container 11 at a position directly below the liquid lift pipe 23 that vertically enters the intermediate container 11 of the pump body 22 . A gas bubbling porous plug 32 is embedded in the bubble inlet 31, and a gas supply pipe 35 is connected to the bubble inlet 31 via a metal fitting 34. The compressed gas reservoir 3 is connected to the gas supply pipe 35 via a flow rate control valve 37.
9 is connected.

The pump main body 21 is supported by a lifting device 41 as shown in FIG. A support 42 is erected adjacent to the intermediate container 11, and an arm 43 is slidably fitted inside the support 42. The pump body 21 is held at the tip of the arm 43 via a holding fitting 44, and the winch 4 is held at the rear end.
The end of the wire 46 wound around the drum 46 of No. 5 is fixed. When the amorphous metal manufacturing apparatus is to be stopped, the pump main body 21 is lifted out of the intermediate container 11 and the tundish 4 by the lifting device 41.

In the apparatus configured as described above, argon gas is supplied from the compressed gas reservoir 39 to the bubble blowing port 31 through the gas supply pipe 35 . The molten metal M around the exit side of the bubble blowing port 31 and the argon gas mix to form a gas-liquid mixture. Since the specific gravity of this gas-liquid mixture is smaller than that of the molten metal alone, it is pushed up by the molten metal M outside the liquid lift pipe 23 and rises inside the liquid lift pipe 23 to be lower than the liquid level in the intermediate container 11. reach upwards.

This can be expressed in the following formula.

γ _n (H _s + H + Δh) = γ H _s (1) γ _n : Average specific weight of the gas-liquid mixture in the liquid lift pipe 23 (Kg/m ² sec ² ) H _s : Intermediate container 11 in the liquid lift pipe 23 Immersion depth (m) in the pump body 22 H: Lifting head (m) Δh: Flow resistance such as friction loss and exit loss within the pump body 22 (m) γ: Specific weight of molten metal (Kg/m ² sec ² ) Intermediate container The gas-liquid mixture of molten metal and gas that has reached above the liquid level in No. 11 is separated into gas and molten metal due to the difference in specific gravity, and the gas is discharged outside the system through the exhaust hole 29, and the molten metal is 4
Flow inside. As a result, the molten metal M in the intermediate container 11 decreases, but this decreased amount is replenished from the ladle 1, and the level of the molten metal M in the intermediate container 11 can be maintained within a certain range. There is.

When the hot water level in the tundish 4 reaches a predetermined level, the stopper 5 is operated to supply the molten metal in the tundish 4 to the nozzle 6. Nozzle 6
Molten metal is ejected from the molten metal onto the circumferential surface of the cooling roll 8 rotating at high speed, and is rapidly cooled to obtain an amorphous metal ribbon.

In the production of amorphous metal ribbon, the amount of molten metal supplied per unit time is very small, and the amount of molten metal supplied per unit time is very small.
Since it is difficult to constantly supply the molten metal M in the ladle 1 from the ladle 1 to compensate for the decrease in the molten metal M in the intermediate container 1.
When the height of the hot water in the ladle 1 falls to a predetermined position, it is preferable to supply the molten metal M from the ladle 1 to the original hot water level. Note that even if the height of the molten metal in the intermediate vessel 11 changes, the flow rate control valve 37 is adjusted so that the amount of molten metal supplied to the tundish 4 is kept as constant as possible to control the amount of gas supplied. Control.

Example 2 FIG. 4 shows another embodiment of the invention.

As shown in this drawing, the intermediate container 51 is
It consists of a hot water pan 52 into which the molten metal M is poured, and a hot water delivery portion 53 which is deeper than the hot water pan 52 and whose cross section is narrower than the hot water pan 52.

Lifting pipe 57 of the pump body 56 of the bubble pump 55
The inlet extends to near the bottom of the hot water delivery section 53.

Other configurations of this embodiment (tandice,
The elevating device for the pump body, etc.) is substantially the same as in the first embodiment, and the operation of the device is also the same in both embodiments.

Here, the lifting height Hm and the immersion depth H _s of the lifting liquid pipe 57
The relationship between H and m (the maximum is when the intermediate container is filled with molten metal, and the minimum is when the liquid level has fallen to the bottom of the water pan 52) is that even when H _s is the minimum, the efficiency of the bubble pump is such that H It is desirable that _s /H=1.5 to 2.3.

In this embodiment, the hot water pan 5 of the intermediate container 51
If the internal volume of the hot water supply section 2 is made larger than that of the hot water delivery section 53, the amount of remaining hot water can be reduced accordingly. Second
When the intermediate container 11 is arranged in one stage as shown in the figure, when the supply of molten metal M from the ladle 1 is finished, the intermediate container 11
As long as the supply of hot water from the hot water to the tundish 4 continues, the level of hot water in the intermediate container 11 will continue to fall. And H _s /H
When the value falls below a certain value, even if the gas flow rate is increased, almost no molten metal will be supplied from the intermediate container 11 to the tundish 4, and a considerable amount of residual metal will be generated in the intermediate container. Therefore, in terms of yield, it can be said that it is better to form the intermediate container with a two-tiered bottom as in this embodiment.

Embodiment 3 FIG. 5 shows still another embodiment of the present invention.

In this embodiment, the hot water delivery section 63 of the intermediate container 61
is divided into an upper part 64 and a lower part 65 near the hot water pan 62. The part where both parts 64 and 65 touch is a flange-like joint part 66, and the hot water delivery part 6
3. Leakage of molten metal M from 3 is prevented. Also,
A heating device 69, such as an electric heater, is disposed in the lower part 65 of the hot water delivery section 63, which heats the molten metal M to increase its fluidity, and also solidifies and solidifies the molten metal M in the hot water delivery section 63. prevent.

When the amorphous metal manufacturing work is finished and the apparatus is stopped, the lower part 65 of the hot water delivery part 63 is removed from the upper part 64. The molten metal M remaining in the lower part 65 of the hot water delivery section 63 is transferred to a mold or the like, recovered, remelted, and supplied to the tundish 4 again from the ladle 1 via the intermediate container 61. If the hot water delivery section 63 is made separable into upper and lower parts, it becomes easier to dispose of the remaining hot water.

Embodiment 4 FIG. 6 shows still another embodiment of the present invention.

The bottom surface of the hot water receiving portion 72 of the intermediate container 71 is connected to the hot water sending portion 7.
3, the lower end of the hot water delivery portion 73 opens downward and is provided with a flange 74.

A sliding plate 76 is slidably in contact with the lower surface of the flange 74 of the hot water delivery portion 73, and the gas bubbling porous plug 32 is provided in the center of the sliding plate 76, and a through hole 77 is provided near the end. . Also, a rod 7 of a hydraulic cylinder 78 is attached to one end of the sliding plate 76.
9 are connected.

During amorphous metal manufacturing work, porous plug 3
The sliding plate 76 is positioned such that the liquid pump 2 is directly below the liquid lift pipe 83 of the bubble pump 81. When the amorphous metal manufacturing work is finished and the equipment is stopped, the hydraulic cylinder 78 is driven to open the through hole 7.
The sliding plate 76 is displaced in the horizontal direction so that the liquid pump 7 is located directly below the liquid lift pipe 83. The molten metal M remaining in the intermediate container 71 flows into the hot water delivery part 73 from the lifting receiving part 72 with an inclined bottom surface, and flows into the through hole 7.
7 and is recovered by a mold 90 set just below this.

A communication pipe 87 in the pump body 82 of the bubble pump 81 is inclined toward the tundish 4 side. Then, an exhaust hole 84 is provided directly above the liquid pumping pipe 83.
Gas blowing holes 88 are provided directly above the discharge pipes 85, respectively.

In the communication pipe 87, the molten metal M flows so as to create a space between it and the pipe wall. An inert gas such as argon is supplied to this space from the gas blowing hole 88 to prevent oxidation of the molten metal.

When blowing inert gas into the liquid lift pipe through a porous plug, it is desirable for efficiency that fine bubbles be distributed as uniformly as possible in the cross section of the liquid lift pipe, and fluctuations in the flow rate of molten metal can be further reduced. .

Generally, in a porous plug, the smaller the gas flow rate per unit area of the gas discharge surface, the finer the bubbles are formed. This is because when the gas flow rate is small, gas is preferentially released from the pores that are scattered on the gas discharge surface and are separated from each other and are easy for gas to exit, so that coalescence of bubbles can be avoided. Therefore, for the same gas flow rate, the larger the area of the gas discharge surface, the more fine bubbles will be formed.

In order to obtain such fine bubbles, as shown in FIG. It is preferable that the gas discharge surface is completely contained within. At this time, in order to ensure a passage for the molten metal M, it is necessary that the porous plug 32 does not block the liquid lift pipe 58.

In general, porous refractories have high porosity due to the need to ensure a predetermined amount of ventilation, and therefore have low strength and corrosion resistance. Therefore, when forming the porous plug 32, it is desirable to reinforce the periphery of the porous refractory with a refractory 33 that has higher strength than the refractory and is less susceptible to attack by molten metal.

In addition to the method of blowing gas from the bottom through a porous plug, it is also possible to blow gas by providing a bubble blowing port near the inlet of the liquid pumping pipe.

As mentioned above, it is better for the intermediate container to have a larger internal volume of the hot water receiving part than the internal volume of the hot water delivery part.
A more specific shape is determined by the amount of molten metal, the relationship with surrounding equipment, etc. From the point of view of reducing the amount of remaining hot water, if the shortest distance between the liquid lift pipe and the inner wall of the hot water delivery part in both the horizontal and vertical directions and the immersion depth of the liquid lift pipe are the same, then the horizontal direction of the space in the hot water delivery part A circular cross section is more advantageous than a rectangular one. This is clear from FIG. 8, which shows a horizontal cross section of the hot water delivery section into which the liquid lifting pipe is inserted. For example, assume that the outer diameter of the liquid lift pipe 58 is 12 cm. It is also assumed that the diameter of the inner wall 53 of the hot water delivery section with a circular cross section is 16 cm, and that the inner wall 54 of the hot water delivery section with a rectangular cross section is circumscribed by that of the circular cross section. At this time, the liquid lift pipe 58
The horizontal cross-sectional area between the outer periphery and the inner walls 53 and 54 of the hot water delivery portion is 88.0 cm ² in the case of a circular cross-section, respectively.
In the case of a rectangular cross section, it is 142.9 cm ² , and the former is only about 60% of the latter.

Non-metallic inclusions in the molten metal are adsorbed by air bubbles in the lift tube of the pump body and rise to the surface of the liquid at a location where the air bubbles and the molten metal are separated, together with the air bubbles. This so-called bubble separation effect reduces the amount of nonmetallic inclusions that enter the tundish together with the molten metal, thereby reducing product defects caused by nonmetallic inclusions. Refractory materials that easily attract inclusions to the inner wall of the bubble pump, such as
For Al ₂ O ₃ inclusions, CaO-based refractories and
If SiO ₂ -based inclusions are coated with a CaO-based or MgO-based refractory, the amount of inclusions in the product can be further reduced.

Example of Production of Amorphous Metal The present invention was carried out for supplying molten metal M from the intermediate container 51 to the tundish 4 in the facility for producing an amorphous metal ribbon shown in FIG. In this example, the specific gravity of the molten metal is 7.2, the temperature is 1400°C, the length of the slit 7 of the nozzle 6 is 15 cm, and the width of the slit 7 is 15 cm.
0.06 cm, and the speed of the molten metal ejected from this nozzle slit 7 is 150 cm/sec. In this case, the replenishment amount of molten metal M is 135 cm ³ /sec. The conditions for securing this replenishment amount are that the inner diameter of the liquid lift pipe 57 of the bubble pump 55 is 81 mm, and that the hot water level of the intermediate container 51 is approaching the hot water delivery section 53, H _s = 310.
When the tundish was full of molten metal, argon gas was blown in from the bubble blowing port 31 and casting was started under the conditions that mm and H = 150 mm. At this time, the maximum gas flow rate was about 20 Nl/min, and a predetermined amount of molten metal M could be supplied very smoothly and continuously to the tundish 4 without clogging.

This invention is not limited to the above embodiments. For example, the cooling body may be an endless belt instead of a cooling roll. In addition, the hot water receiving portion 5 of the intermediate containers 51, 61 shown in FIGS. 4 and 5
The bottom surfaces of 2 and 62 may be inclined as shown in FIG. Furthermore, a heater may be provided in the water pan shown in FIGS. 4 and 6, and the pump body 56 shown in FIGS. 4 and 5 may be replaced with that shown in FIG. 6.

(Effects of the Invention) According to the present invention configured as described above, there is no need to provide a nozzle stopper or a sliding plate between the ladle and the tundish, and since the inside of the pump body is a gas-liquid mixture, only liquid can be used. The inner diameter of the tube is larger than in the case of . Therefore, the device for supplying molten metal has a simple structure, and the flow path is less likely to be clogged.

The amount of molten metal supplied can be adjusted by adjusting the amount of bubble gas sent to the bubble pump. Therefore, it becomes easy to supply and adjust the minute amount of molten metal, which is particularly required in the production of amorphous metals, and also facilitates continuous operation.

[Brief explanation of the drawing]

Figure 1 is a vertical cross-sectional view showing a conventional device for supplying molten metal from a ladle to a tundish through a sliding plate in the production of amorphous metal ribbon, and Figures 2 and 3 use a bubble pump. Fig. 2 is a longitudinal sectional view, Fig. 3 is a perspective view, Fig. 4 is a longitudinal sectional view showing another example of the apparatus of the invention, and Fig. 5 is a cross-sectional view of the present invention. Fig. 6 shows still another example of the present invention, and is a vertical sectional view of a device in which a part of the intermediate container can be divided into upper and lower parts. A longitudinal cross-sectional view of a device equipped with a riding plate that separates bubbles and molten metal directly above the intermediate container. Figure 7 shows a liquid pump and a porous plug for distributing fine bubbles as uniformly as possible over the cross section of the bubble pump. FIG. 8 is an explanatory view showing the structure, and FIG. 8 is an explanatory view showing a horizontal cross section of the hot water delivery portion of the intermediate container having circular and rectangular cross sections. 1...Ladle, 4...Tundesh, 6...Nozzle, 8...Cooling body, 11, 51, 61, 71...
Intermediate container, 21, 55, 81...bubble pump, 2
2, 57, 82...Bubble pump main body, 31...Bubble gas inlet, 32...Bubble gas flow rate adjustment valve,
M... Molten metal.

Claims (1)

[Claims] 1. In an amorphous metal manufacturing apparatus consisting of a cooling body and a tundish equipped with a nozzle for injecting molten metal onto the surface of the cooling body moving at high speed, an intermediate container adjacent to the tundish and a pump body are connected between the intermediate container and the tundish. A molten metal supply device comprising: a bubble pump that is spanned between the intermediate container and the tundish for feeding the molten metal from the intermediate container to the tundish; and a bubble gas flow rate adjustment valve provided on a pipe that supplies bubble gas to the pump body. .