JPH0341260B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tundish device used in a continuous metal strip casting device. The tundish according to the invention allows the orifice of the tundish to be heated before and during the strip casting operation. In particular, in the present invention, a heat conductive layer is attached to the portion where the reaction gas impinges on the tundish material.

With the development of strip casting equipment, it has become clear that the orifice passageway that supplies molten metal to the casting surface has an important effect. In particular, the slot forming the orifice passage must have a width that is approximately uniform over the entire length in the longitudinal direction. The clearance between the lip of the orifice and the casting surface between casting operations is also important. As strip widths and similar orifice passage widths increase, maintaining slot dimensions between casts and minimizing the possibility of orifice passage solidification between casts is an important issue.

Applicant's application ``Heating Orifice for Strip Casting Apparatus'' of the same date describes an apparatus for heating the orifice of the tundish of a strip casting apparatus. Generally speaking, the tip of at least one blowpipe attached to the tundish opens into a space within the tundish. Supplying reactive gas into the space via the blowpipe transfers heat to the lip forming the orifice passageway, keeping the lip at a high temperature before and during casting operations.

However, such reactive gases have an adverse effect on the tundish material, especially when used for long periods of time. For example, continuously impinging hot gases cause flame erosion and chemical corrosion to the tundish material, particularly in the areas of flame impingement.

Therefore, a new metal strip casting device was developed that allows for heating of the orifice passage, and that the tundish material suffers from flame erosion as a result of heating.
It is desired to prevent chemical corrosion etc. from occurring.

The new continuous strip casting apparatus of the present invention includes a tundish for receiving and holding molten metal, and supplies the molten metal to a casting surface through an orifice passage formed between two spaced apart lips of the tundish. From the orifice aisle
Linear speed 200~ as interval within 0.120in (3mm)
Pass at 10,000ft/min (60 to 3,000m/min).
According to the invention, a blowpipe is provided which extends through the tundish with its tip opening into a space formed in the tundish adjacent to at least a portion of the material forming the lip of at least one of the orifice passages. A device is provided for conveying the reaction gas into the space through the blowpipe and an opening for exhausting the combustion products from the reaction gas from the space of the tundish. One lip forming the orifice passage is made of a plate resistant to molten metal. According to the invention, a thermally conductive layer is provided within the space within the tundish where the reactant gas from the blowpipe impinges on the tundish material.

An advantage of the present invention is that the orifice passage of a strip casting machine can be heated without adversely affecting the tundish material during heating.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a new strip casting apparatus in which at least one of the surfaces forming the orifice passage of the tundish can be continuously coated before the casting operation without adversely affecting the tundish material.
It is possible to heat the inside and the back.

It is another object of the present invention to provide a thermally conductive layer where the reactant gases impinge on the tundish material to protect the tundish material from flame action and chemical attack, and to further promote heat transfer to provide a heating condition for the orifice passageway. It is important to keep it.

Another advantage of the invention is that the dimensions of the slot forming the orifice passage of the strip casting apparatus remain constant even when casting relatively wide strips.

The present invention will be described with reference to illustrative embodiments and drawings.

The figures show various embodiments of the tundish according to the invention. As shown in FIGS. 1-4, this apparatus has a tundish 10. The cavity 12 of the tundish 10 is called a molten metal injection passage. Cavity 12 receives and holds molten metal. Molten metal within the tundish 10 is supplied onto the casting surface 16 via a nozzle or orifice passageway 14 of the tundish 10.

In the present invention, the orifice passage 14 is
upper lip 18 and lower lip 19
to form between. As shown in Figure 2, Lip 1
The gaps 8 and 19 are approximately equal over the entire length of the orifice passageway 14 and are at least 0.010 inches (0.25 mm) apart.

In the preferred embodiment, molten metal is supplied from an orifice passageway 14 to a casting surface 16 of a casting wheel. The cast ring may be, for example, a water-cooled deposit-hardened copper alloy and may be 99% copper. Although copper and copper alloys were selected for their high thermal conductivity and wear resistance, other materials may be used for the casting surface 16. In operation of the device of the present invention, the casting surface 1
6 is circular, flat, or elliptical, the linear velocity in front of the orifice passage is 200 to 10,000 ft/min (60 to
3000m/min).

In the illustrated example, the tundish is at least one
It has at least one upper block 20 and at least one lower block 30. In this specification, upper and lower, front and back refer to the casting surface 16, and upper and rear refer to the casting surface 16.
refers to a location far away from The upper and lower blocks 20, 30 of the tundish 10 are secured to each other in a vertical arrangement. The vertical arrangement is detailed in the same application. The secured block prevents molten metal within passageway 12 from leaking through the joint.
Although the orifice passage 14 is at the interface shown in FIG. 2, the orifice passage 14 is different.

The required number of intermediate blocks, e.g. block 22,
24 are placed between the upper and lower blocks 20 and 30 and aligned vertically to form a tundish. They can be of various constructions, and can be made of molten metal resistant materials that are horizontally aligned and bonded to each other, and can be of monolithic construction.

The block used in the apparatus of the present invention is made of a material that is not susceptible to erosion by molten metal. A fire-resistant board, for example an insulating board made of fiberized kaolin, is suitable in this respect. Other materials include graphite, alumina graphite, clay graphite, refractory clay, quartz, boron nitride, silicon nitride, silicon carbide,
Blocks may be made of boron carbide, alumina, zirconia, stabilized zircon silicates, silica, magnesia, chromium magnesite, combinations thereof, and the like.

As a suitable example, a 1.5 inch (38 inch)
Depending on the strip casting conditions, thicker or thinner blocks can be used. A 1.5in (38mm) thick block was used because it is easily available on the market. Fiberized kaolin blocks are relatively inexpensive and easily drilled and cut into the desired shape. Other materials are also suitable, such as those mentioned above. It is also possible to cast without cutting.

Cavity 12 of the illustrated tundish 10
has at least one injection passage section 32.
The introduction passage section 32 extends substantially vertically within the tundish 10 and communicates with a base passage section 34 formed as a hollow section in the lower part of the tundish. , the opening of the introduction passage section 32 is as shown in FIGS.
Form at the top of the tundish. Other positions are also possible. As shown in the figure, the upper end of the opening is curved into a funnel shape to facilitate the injection of molten metal.

Base passageway 34 and orifice passageway 14 represent important features of the strip casting apparatus according to the present invention. The base passageway 34 is carved or cast into the bottom of the tundish 10. In the illustrated example, most of the bottom surface 38 of the base passageway 34 is below the vertical height of the orifice passageway 14. As a preferred example, at least a portion of the bottom surface 38 of the base passage 34 is located at least below the orifice passage 14.
Located at 0.3in (7.6mm). Furthermore, the bottom surface 38 of the base passage 34 faces upwardly toward the orifice passage at an angle of at least 30 degrees from horizontal.

Orifice passage 1 for supplying molten metal to the casting surface
4 has a substantially uniform width dimension over the entire length direction. This width dimension W is at least 0.010 in (0.25
mm) and less than 0.120in (3mm), in a preferred example
It should be 0.080in (2mm) or less. More suitable width dimension W
is 0.020~0.060in (0.5~1.5mm), furthermore 0.030~
A range of 0.050 in (0.76-1.3 mm) is preferred.

Orifice passage 14 can have various configurations. In accordance with a preferred embodiment of the invention, at least one lip forming the orifice passageway 14 is comprised of a plate that is resistant to molten metal. For example, in the example shown in FIG.
0 and a portion of the front wall of the tundish 10 forming the lower lip 19 of the orifice passage. As another method, orifice passage 1
4 can be formed between the lower plate and the tundish, or between the two opposing plates. Regardless of the method of forming the orifice passage 14, it is necessary to maintain the above-mentioned dimensional range.

In accordance with the invention, at least one space is formed within the tundish 10, which space is formed in contact with at least a portion of the material forming at least one lip of the orifice passage. This space communicates with the bottom of a chimney 46, which will be described later. Furthermore, this space extends between the chimneys as shown in FIGS. 2 and 4. Alternatively, it can be formed across substantially the entire length of the tundish 10, as shown in FIG. 5, on the entire length of the plate forming one of the lips of the orifice passage. The illustrated example includes plates 40, 70 forming the lip of the orifice passage. In this case, a portion of the tundish material near the outside of the plate is removed to create the required space. As discussed below, a reactant gas is introduced into the space and the heat generated from the gas heats the orifice passage through the tundish material. Therefore, the space should be placed close enough to the orifice passage to increase the heating effect. The extent to which it is heated is necessarily a function of the heating temperature and the thermal conductivity of the tundish material.

As mentioned above, at least one surface forming the orifice passageway is formed by the bottom surface of the plate 40 which is resistant to separate molten metal. This plate 40 is integrally attached to or otherwise supported by the tundish 10. As shown, the upper lip 18 of the orifice passageway 14 includes a plate 40 of material resistant to molten metal.
The lower surface of During strip casting, the upper lip 18 of the orifice passage 14 is of greater importance than the lower lip 19, and for this reason a plate 40 having a significantly greater resistance to molten metal is used as the upper lip. However, only the lower lip 19 or the upper and lower lips 18, 19 forming the orifice passage 14 can be used.
can be formed by plates 40 and 70 as shown in FIGS. Boards 40 and 70 are tandaishi 1
The material should be more resistant to molten metal than the other parts of 0. As shown in FIG. 2, the plate 40 fits into a slot cut into the bottom of the intermediate block 24 of the tundish 10. The plate 40 can also be a block or part of a block of the tundish 10. The plate 40 is larger than the longitudinal dimension of the orifice passage. Thus, the outer edge of plate 40 is
When assembled as shown in Figures 1 and 2, the block 24,
It is caught between 30 and 30 minutes.

In a preferred example, the tundish 10 is made primarily of fiberized kaolin, and the orifice passage 14
is formed of a plate 40 of boron nitride. Examples of suitable materials for forming the tandate and plate include silicon nitride, silicon carbide, boron carbide, silica, alumina, zirconia, stabilized zircon silicate, graphite, alumina graphite, quartz, magnesia, chromium magnesite, and the like. There is a mixture.

As shown, one or more blowpipes pass through the tundish 10 with the tips 44 entering the space near the orifice passage. As shown in FIGS. 1, 2 and 5, the blowpipe 42 is located within the orifice passageway 14 within the space.
The plate 40 forming the upper lip 18 of the plate is heated.
In the preferred embodiment, a plurality of blowpipes 42 are mounted on the tundish, with tips 44 facing the outer surface of plate 40 within the space. Further, as shown in FIGS. 1 and 2, a chimney 46 formed in the tundish 10 discharges the combustion products of the fuel supplied by the blowpipe 42 from the space of the tundish 10.

In the example shown in Figures 3 and 4, the orifice passage 1
Plates 40, 7 forming upper and lower lips 18, 19 of 4
heating the space formed within the tundish near zero. In addition to the blowpipe 42 described above for heating the upper lip 18 of the orifice, a blowpipe 72 is mounted on the tundish 10, the tip 74 of which is directed into the space adjacent the lower plate 70 to heat the lower lip of the orifice passageway 14. chimney 76
An opening is formed in the tundish 10 to open the blowpipe 72.
The combustion products of the reaction gases directed into the space towards the plate 70 are discharged from the space.

As shown in FIG. 5, the number of blowpipes and the number of tips to be attached to each blowpipe are arbitrarily determined, and are usually determined according to the width of the strip to be cast from the tundish 10. By using the required oxygen blowpipe,
Generates and retains sufficient heat within the space
It is transmitted through the tundish material to the lip of the orifice passage to maintain the required high temperature in the orifice passage before and during strip casting. Plate 40,7
When using 0, the entire plate is brought to the required temperature before strip casting. In a preferred embodiment, there is one blowpipe tip every 2 to 3 inches (50 to 70 mm) of orifice passage. When the heating temperature is set close to the melting point of the alloy to be cast, that is, within 10% of the melting point, solidification of the metal in the orifice passage 14, particularly at the start of the casting operation, can be prevented. Additionally, by preheating the plates 40, 70 to near or above metal casting temperatures, thermal expansion or contraction may occur prior to the start of casting and appropriate compensation may be initially provided. Therefore, by preheating, the orifice dimensions and the gap between the casting surface and the orifice are maintained at set values throughout the casting operation.

In a preferred embodiment, the hot reactant gas is routed to a blowpipe. This gas passes through the tip of the blowpipe and a flame forms within the space and is directed toward the material forming the lip of the orifice passage. Examples of reactive gases include mixtures of acetylene and air, acetylene and oxygen, and natural gas and oxygen.

As shown, in order to prevent the corrosive effects of flames on the plate 40 or the plates 40, 70, according to the invention a thermally conductive layer 48, 78, which is more resistant than the material of the plates 40, 70, is applied to the top plate. At least a portion of the upper surface of the upper surface of the lower plate 40 and the lower surface of the lower plate 70, the flame is
It sticks to the part that collides with 0. This layer 48, 78
prevents flame erosion and local chemical corrosion, and also prevents plate 4
Transfers heat within 0.70. In a preferred example, layer 4
8 and 78 are graphite having a thickness of 3/16 to 1/4 inch (5 to 6 mm), but other materials are also possible.
To install one or more protective layers on the boron nitride board, it is secured using graphite support cement or other refractory coating material. A thermally conductive layer according to the present invention shall include a material that prevents thermal and chemical attack and is functionally capable of transmitting heat.

As shown in FIGS. 1 and 3, a drain plug 62 is provided in the lower portion of the tundish. The drain plug is vertically below the orifice passageway 14 in relation to gravity. The purpose of the drain plug 62 is to stop the supply of molten metal from the orifice passageway 14 and stop the casting operation. It is important to stop the casting operation within as short a time as possible. Nozzle 1 at the end of the casting operation
The flow of molten metal from 4 results in an uneven or intermittent metal flow. This intermittent flow flows over a rapidly moving casting surface, at which time the control for producing the strip has already stopped. If this uncontrolled intermittent leakage of molten metal drips through the orifice passageway at the end of the casting operation, it will scatter over the legitimate casting product, rendering the strip defective and damaging parts of the casting equipment. There are things to do. In addition, to ensure reuse of the tandem tray, the cavity 12
The molten metal within must be drained from the tundish at the end of the casting operation. When the plug 62 is removed, almost all of the molten metal is discharged from the tundish, and the plates 40 and 7 forming the orifice passage 14 are removed.
0 can be reused for the next casting operation. The molten metal flowing out from the tundish through the plug is received in a required container.

Although the present invention has been described with reference to preferred embodiments, the present invention can be modified in various ways, and the embodiments and drawings are illustrative and do not limit the invention.

[Brief explanation of drawings]

1 is a partially sectional side view of a tundish having a heating device for a plate forming a part of an orifice passage according to the present invention; FIG. 2 is a front view of the tundish of FIG. 1; and FIG. FIG. 4 is a front view of the tundish of FIG. 3, and FIG. 5 is a front view of the tundish of another embodiment. 10... Tunnel, 12... Cavity, 14... Orifice passage, 16... Casting surface,
18, 19...lip, 20, 22, 24, 30
...Block, 40,70...Board, 42,72...
...Blowpipe, 44,74...Tip, 46,76...Chimney, 48,78...Heat conductive layer.

Claims (1)

[Scope of Claims] 1. A strip casting device is provided with a tundish for receiving and holding molten metal;
Molten metal is supplied to the casting surface through orifice passages formed between spaced apart lips, and the casting surface is spaced within 0.120 in (3 mm) of the orifice passages at a linear velocity of 200 to 10,000 ft/min (60 to 3000
m/min); through at least one space formed in the tundish adjacent to at least a portion of the material forming the lip of at least one of the orifice passages; at least one blowpipe opening into the orifice passage; supplying a reactant gas through the blowpipe into the space to generate the required heat in the space and transferring the heat through the lip to at least a portion of the orifice passage; and at least one opening communicating with said space for discharging the combustion products of the reaction gases from said space of the tundish; in said space in said tundish, the reaction gases from the blowpipe enter the tundish. A strip casting machine with a heated orifice, characterized in that it is provided with a heat-conducting layer at the point where it impinges on the material. 2. The device of claim 1, further comprising a thermally conductive layer on the outer surface of the plate forming at least one lip of the orifice passage. 3 The tandate is made of boron nitride, quartz, graphite, clay graphite, refractory clay, silicon nitride, silicon carbide, boron silica carbide, alumina,
2. The device of claim 1, wherein the device is made of a molten metal resistant material selected from the group consisting of zirconia, stabilized zircon silicates, magnesia, chromium magnesite and mixtures thereof. 4. The plate is made of boron nitride, quartz, graphite, clay graphite, refractory clay, silicon nitride, silicon carbide, boron carbide, silica, alumina, zirconia, stabilized zircon silicate, magnesia, chromium magnesite, and mixtures thereof. 3. The device of claim 2, wherein the device is made of a molten metal resistant material selected from: 5. The device according to claim 2, wherein the plate is made of boron nitride. 6. The device according to claim 1 or 2, wherein the thermally conductive layer is made of graphite.