JPH10211554A - Metal strip coasting device, refractory nozzle for supplying molten metal to casting pool, and metal strip continuous casting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely prevent skull formation at a casting pool by providing a side part opening from which a molten metal is allowed to flow outward in a metal supply nozzle and providing an opening through which a nozzle lower side is communicated directly with a nozzle trough inside in a nozzle bottom part. SOLUTION: The molten metal is allowed to flow out near the casting pool 68 whole surface as two injection flows directing sideward/outward through side part openings 64 so as to be allowed to collide with a casting roll 16 cooling surface immediately near a casting pool 68 surface. The opening 101 can be an additional source to allow metal flow to flow to the casting pool 68 near an underside of a nozzle, a relatively large gas bubble is prevented from stagnating/accumulating overall at an underside of the nozzle. In particular, it is important the side pat openings 64 are arranged at inner ends of two metal supply nozzle 19 half parts. By this method, the molten metal is sufficiently supplied near a center region, skull formation is surely prevented in this region of the pool.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to casting of metal strip. In particular, the present invention is applied to the casting of an iron-based metal strip, but is not limited thereto.

[0002]

BACKGROUND OF THE INVENTION It is known to cast metal strip by continuous casting in a twin roll casting machine. The molten metal is introduced between a pair of horizontal casting rolls that are cooled and rotate in opposite directions, the metal shells are solidified on the moving roll surface, and the metal shells are united at the roll gap to form a solidified strip product. It is fed downward from the roll gap. As used herein, the term "roll gap" is intended to refer to the entire area where the rolls are closest. The molten metal is poured from the ladle into one or a series of small containers, from which it flows to a metal feed nozzle located above the roll gap and into the roll gap, and consequently roll casting just above the roll gap A casting pool of molten metal supported on the surface can be formed. The end of the casting pool may be a side dam or side plate held in sliding engagement with the roll end surface.

[0003]

While twin roll casting has met with some success for non-ferrous metals which solidify rapidly upon cooling, the high solidification temperatures and uneven uniformity on the cooled roll casting surface. There are various problems in applying it to the casting technology of iron-based metal, which is liable to cause defects due to solidification.

Accordingly, much attention has been paid to the design of metal feed nozzles to flow metal into and out of the casting sump smoothly and uniformly.

The apparatus disclosed in US Pat. Nos. 5,178,205 and 5,238,050 each has a metal feed nozzle extending below the surface of the casting pool and immersed in the casting pool. It incorporates means to reduce the kinetic energy of the molten metal flowing down to the bottom end slot outlet. In the device disclosed in US Pat. No. 5,178,205, it is the flow diffuser that reduces the kinetic energy. The flow diffuser has a plurality of flow paths and a baffle located above the diffuser, below which the molten metal flows slowly and uniformly through the elongate exit hole into the casting reservoir to minimize turbulence. In the apparatus disclosed in U.S. Pat. No. 5,238,050, the molten metal stream is allowed to fall and collide with the nozzle inclined side wall surface at an acute collision angle, so that the metal adheres to the side wall surface and exits. Form a flow sheet towards the channel. even here,
The goal is to have a gentle and uniform outflow of metal flow from the bottom of the metal feed nozzle to minimize turbulence in the casting pool.

[0006] Tokuho 5-7053 of Nippon Steel Corporation
No. 7 also discloses a metal supply nozzle adapted to allow a gentle and uniform metal flow to flow down into a casting pool. The metal supply nozzle is provided with a perforated baffle / diffuser to remove kinetic energy from the flowing molten metal, and the kinetic energy-depleted metal stream flows through a series of openings in the nozzle sidewall into the casting pool. The openings are angled such that the metal stream flows along the roll casting surface in the longitudinal direction of the roll gap. That is, the opening on one side of the metal supply nozzle allows the metal flow to flow in one direction in the longitudinal direction of the roll gap, and the opening on the other side allows the metal flow to flow in the other direction in the longitudinal direction of the roll gap, so that the metal flows smoothly along the casting surface. The aim is to minimize the disturbance of the casting pool surface by creating a uniform flow in the casting.

As a result of extensive studies and studies, the present inventors have found that a major cause of defects is that the molten metal prematurely solidifies in the so-called "meniscus" or "meniscus area" where the casting pool surface meets the roll casting surface. I noticed something. The molten metal in each of these zones flows toward the adjacent casting surface, and if solidification of the molten metal occurs before even contact with the roll surface, an irregular initial heat transfer between the metal shell and the roll occurs. This is likely to occur, and as a result, surface defects such as pits, ripple marks, hot water boundaries, and cracks will be formed.

[0008] Prior attempts to make the molten metal flow into the casting pool very uniformly have been made in the area where the metal first solidifies due to shell surface formation, ie, the area that eventually becomes the outer surface of the formed strip. The premature solidification is inevitably intensified to some extent due to the inflow of the metal stream out of the way, so the molten metal temperature in the casting pool surface area between the rolls is much higher than the temperature of the incoming molten metal. Low. If the temperature of the casting pool molten metal in the meniscus area is too low, cracks and "meniscus marks" (marks on the strip caused by the meniscus that solidify with non-uniform casting pool levels) are very likely to occur.

Conventionally, one way to address this problem is to apply a high level of superheating to the incoming molten metal so that the molten metal is allowed to cool down in the casting pool without reaching the solidification temperature before reaching the roll surface. There was a way to do it. However, in recent years, molten metal prematurely solidifies prior to contact with the casting roll surface by taking the measure of inserting the metal supply nozzle directly into the meniscus area of the casting pool to ensure relatively rapid inflow of the molten metal. It has been recognized that minimizing this tendency can effectively address the problem of premature coagulation. This method is much more effective at avoiding surface defects than providing an absolutely steady metal flow to the casting pool, and the casting pool does not solidify until the metal contacts the roll surface. It has been found that some surface variations are acceptable. Examples of such an approach can be found in Japanese Patent Application Laid-Open No. 1-5650 of Nippon Steel Corporation and Australian Patent Application No. 60773/96 of the present applicant.

In order to ensure that the inflowing molten metal is relatively quickly supplied to the meniscus area, a metal supply nozzle having side openings is used, and a laterally outward from the bottom of the metal supply nozzle to the casting roll. It is necessary to supply molten metal. Conventionally, this type of nozzle is completely closed at the bottom end below the side feed outlet, but when this type of nozzle is used, carbon and free oxygen in the refractory nozzle immersion part or in the molten metal in the casting pool molten metal. Large turbulence occurs in the casting pool due to carbon monoxide bubbles generated by a chemical reaction with oxygen contained in the compound. Due to the nozzle design with side openings and closed bottom, the casting pool is stagnant near the bottom of the nozzle, and large bubbles are formed over the bottom of the nozzle,
Accumulation was detected. As the bubbles are formed, they flow up the nozzle side into the casting pool meniscus area, overturning the steady state required for this area. This problem is particularly acute in the casting of silicon / manganese killed steels that contain much more free oxygen and oxygen containing compounds that can be reduced with carbon than aluminum killed steels. It is currently believed that most of the meniscus marks are due to this phenomenon.

The present invention addresses this problem by modifying the bottom design of the metal feed nozzle.

[0012]

According to the present invention, there is provided a metal strip casting apparatus comprising a metal supply nozzle and a distributor disposed above the metal supply nozzle and supplying molten metal to the metal supply nozzle. In the above, the metal supply nozzle is constituted by an elongated upwardly open nozzle trough extending in the longitudinal direction of the roll gap and receiving the molten metal from the distributor, and the metal supply nozzle is configured to flow the molten metal outward from the metal supply nozzle. The metal strip casting apparatus is provided, wherein the nozzle bottom has an opening for directly communicating the lower side of the nozzle and the inside of the nozzle trough.

The present invention also provides a method for introducing molten metal between casting rolls through an elongated metal supply nozzle disposed along the roll gap between the pair of cooled casting rolls and supporting the molten metal above the roll gap. In a continuous metal strip casting method in which a casting roll is rotated to form a solidified strip fed downward from a roll gap by forming a molten metal casting pool, a metal feed nozzle is extended in a longitudinal direction of the roll gap and melted. It consists of an elongated nozzle trough that opens upward to receive the metal, the metal supply nozzle is provided with a side outlet through which the molten metal flows outward from the metal supply nozzle, and the nozzle bottom is directly connected to the lower side of the nozzle and the inside of the nozzle trough. Provided is a method for continuously casting a metal strip, comprising a communicating opening.

The present invention further provides a refractory made of a refractory material made of carbon forming an elongated nozzle trough that opens upward to receive the molten metal, and a side through which the molten metal flows laterally outward from a metal supply nozzle. The present invention provides a refractory nozzle for supplying molten metal to a casting pool, comprising: an opening at the bottom of the nozzle; and an opening at the bottom of the nozzle for directly communicating the lower side of the nozzle with the inside of the nozzle trough.

[0015] The direct communication between the lower side of the nozzle and the inside of the nozzle trough may be for controlling the release of bubbles from the lower side of the nozzle.

The metal flow can descend through the opening at the bottom of the nozzle and the stagnation of the casting pool below the nozzle can be prevented. The opening at the bottom of the nozzle may be to prevent excess carbon in the casting pool near the underside of the nozzle from causing melting of the metal supply nozzle.

Alternatively or additionally, the opening at the bottom of the nozzle may be used to prevent the opening at the bottom of the nozzle from venting upward from below the nozzle to form bubbles in the upper region of the casting pool. Things.

Preferably, the opening at the bottom of the nozzle is spaced apart along the longitudinal direction of the nozzle.

Preferably, the lower side of the nozzle is recessed upward, and the opening is arranged in a line along the highest portion of the lower side recessed above the nozzle. The lower end of the nozzle which is concave upward may be closed to form an upper trough-shaped lower nozzle.

The opening at the bottom of the nozzle may be a round hole formed in the floor of the nozzle trough. Alternatively, these openings may be formed as holes tapered downward and outward to promote upward ventilation in preference to metal flow fall.

[0021]

BRIEF DESCRIPTION OF THE DRAWINGS In order to more fully describe the present invention, certain methods and apparatus will be described in more detail with reference to the accompanying drawings.

FIGS. 1 to 12 show an embodiment of the present invention. The illustrated casting apparatus has a main machine frame 11 rising from a factory floor 12. A casting roll cart 13 supported by the main machine frame 11 is horizontally movable between an assembly station 14 and a casting station 15. A pair of parallel casting rolls 16 carried by the casting roll carriage 13 are supplied from the ladle 17 to the distributor 1 during casting.
Molten metal is supplied through 8 and a metal supply nozzle 19. Since the casting roll 16 is water-cooled, a metal shell is formed on the surface of the moving roll and is joined together at the roll gap to produce a solidified strip product 20 at the roll exit. This coagulated strip product 20 may be sent to a main coiler 21 and then to a second coiler 22. Since the container 23 is mounted on the main machine frame 11 adjacent to the casting station 15, molten metal can escape to the container 23 via the overflow port 24 of the distributor 18.

The bogie frame 31 constituting the casting roll bogie 13 is mounted on the rails 33 by the wheels 32, and the rails 33 extend along a part of the main machine frame 11, so that the entire casting roll bogie 13 moves to the rails 33. It will be listed as possible. The casting roll 16 is rotatably mounted on a pair of roll cradle 34 carried by the carriage frame 31. A double-acting hydraulic piston cylinder device 39 that can move the casting roll truck 13 along the rail 33 is connected between the drive bracket 40 of the casting roll truck 13 and the main machine frame 11 to assemble the casting roll truck 13. It can be moved from station 14 to casting station 15 and vice versa.

The casting roll 16 is rotated in opposite directions via a roll drive shaft 41 of an electric motor and a transmission on the bogie frame 31. A series of water cooling passages formed in the copper peripheral wall of the casting roll 16 and extending in the longitudinal direction and separated in the circumferential direction are connected with a roll end from a water cooling conduit in a roll drive shaft 41 connected to a water cooling hose 42 via a rotating gland 43. Cooling water is supplied via the The typical size of the casting roll 16 is about 500 mm in diameter and can be up to 2 m long to produce a solidified strip product up to 2 m wide.

The ladle 17 is entirely conventional and is supported from the overhead crane via a yoke 45 and can be moved from the hot metal receiving station to a fixed position.
By moving a stopper rod 46 attached to the ladle 17 with a servo cylinder, the molten metal is removed from the ladle 17.
Through the outlet nozzle 47 and the refractory shroud 48 to the distributor 18.

The distributor 18 is a wide dish made of a refractory material such as a high-alumina castable having a corrosion-proof lining. One side of the distributor 18 receives the molten metal from the ladle 17 and is provided with the overflow port 24 described above. On the other side of the distributor 18 are a series of vertically spaced outlet openings 52.
Is provided. A mounting bracket 53 for supporting the lower portion of the distributor 18 is for mounting the distributor 18 to the bogie frame 31, and receives the positioning pegs 54 of the bogie frame 31 to accurately position the distributor 18. I have.

The metal supply nozzle 19 is formed of two identical halves made of a refractory material such as alumina graphite and is held end-to-end to form a complete nozzle. FIGS. 5 to 12 show the configuration of the metal supply nozzle 19 half supported by the bogie frame 31 by the mounting bracket 60. FIG. An outwardly protruding side flange 55 is formed on the upper part of the metal supply nozzle 19 and is located on the mounting bracket 60.

The half of each metal supply nozzle 19 is substantially trough-shaped, the metal supply nozzle 19 forming an upwardly open nozzle trough 61 for receiving a molten metal flow 65 flowing down from the outlet opening 52 of the distributor 18. The nozzle trough 61 is formed between a longitudinal side wall 62 and an end wall 70 and can be considered to be laterally partitioned between two ends by two flat end walls 80 of the metal supply nozzle 19 half. The walls 80 together form a complete nozzle. The horizontal floor 63 closing the bottom of the nozzle trough 61 is fitted with the side wall 62 at the chamfered bottom corner 81. The bottom corner 81 of the metal supply nozzle 19 is provided with a long and narrow elongated side opening 64 that is arranged at a constant interval in the longitudinal direction of the nozzle and is spaced apart in the longitudinal direction. The side openings 64 allow the molten metal to pass substantially through the floor 63 of the nozzle trough 61.
It is arranged so that it comes out at the height.

A pair of upstanding flow barrier walls 84 rise from the floor 63 of the nozzle trough 61 adjacent the side openings 64. The flow barrier wall 84 extends continuously over the entire length of the nozzle trough 61, and receives the incoming molten metal stream 6 as described below.
5 constitute an inner trough groove 85.

At the outer end of the metal supply nozzle 19 half, the end wall 7 is provided.
0, a separate molten metal stream 65 is applied to the "triple point" area of the casting sump 68, i.e., the two casting rolls 16
An end formation 87 is provided which faces the area of the casting pool 68 where the and the side weir 56 meet. The purpose of directing the molten metal to the triple point zones is to prevent the formation of "skulls" in these zones due to premature solidification of the molten metal, as described in our Australian Patent Application 3521.
No. 8/97 is described in more detail.

Each end forming portion 87 forms a small upwardly opening reservoir 88 for receiving the molten metal from the distributor 18, and this reservoir 88 extends from the nozzle trough 61 to the end wall 70.
Are separated by The upper end 89 of the end wall 70 is lower than the upper end of the nozzle trough 61 and the upper end of the reservoir 88, and as will be described in detail below, the nozzle trough 6 when the reservoir 88 overflows.
It can act as a weir allowing backflow to one.

The reservoir 88 is formed as a shallow dish having a flat floor portion 91, an inclined inner surface 92 and side surfaces 93, and a curved upright outer surface 94. A pair of triple point injection passages 95 extend from the lateral outside of the reservoir 88 just above the height of the floor portion 91 and connect to a triple point injection port 96 below the end forming portion 87. The triple junction spout 96 inclines downward and inward to supply molten metal to the triple junction area of the casting pool 68.

The molten metal falls from the outlet opening 52 of the distributor 18 to the bottom of the nozzle trough 61 as a series of vertically free falling molten metal streams 65. Molten metal flows out of the nozzle trough 61 through the side opening 64 and the casting roll 1
A casting pool 68 supported above the roll gap 69 between the six is formed. Surrounding the casting pool 68 by the ends of the casting roll 16 are a pair of side dams 56 which are
Is held in contact with the end 57. The side dam plate 56 is made of a strong refractory material such as boron nitride and is attached to the plate holder 82. The plate holder 82 includes a pair of hydraulic cylinder devices 83
The side dams 56 are engaged with the ends of the casting roll 16 to form an end closure for the casting pool 68 of molten metal.

In the casting operation, by controlling the metal flow, the casting pool 68 is held at a height at which the lower end of the metal supply nozzle 19 is immersed in the casting pool 68, and
Two horizontally spaced side openings 64 are formed in the casting reservoir 68.
Placed just below the surface of the The molten metal is supplied to the casting pool 68
It exits through the side openings 64 as two jets directed laterally outward, generally adjacent to the surface of the casting sump 68, so as to impinge on the cooling surface of the casting roll 16 very close to the surface. It has been found that this maximizes the temperature of the molten metal stream 65 supplied to the meniscus area of the casting pool 68 and significantly reduces cracking and meniscus mark formation on the strip surface.

The molten metal stream 65 falls into the inner trough groove 85, and between the two upstanding flow barrier walls 84, the nozzle trough 6
It collides with the first floor 63. Thus, the impinging metal flow strikes the flow barrier wall 84 and flows outward, so that the side openings 64
To prevent direct flow to Since the kinetic energy of the molten metal is significantly reduced by secondary collisions with the flow barrier wall 84, the molten metal initially falls within the inner trough groove 85 and then crosses the flow barrier wall 84 in a substantially steady continuous flow condition. To the side opening 64. To ensure that kinetic energy is reduced, it is important to construct the inner trough groove 85 by meeting the flat floor and the upright side wall 62 at sharply defined corners to create a double impact effect. .

The outlet opening 52 and the side opening 64 of the distributor 18
Is shifted in the longitudinal direction of the nozzle, so that the molten metal stream 65 collides with the floor 63 of the nozzle trough 61 at a position between the pair of side openings 64 arranged side by side. The casting pool 68 is raised slightly above the bottom of the metal supply nozzle 19 so that the surface of the casting pool 68 is slightly above the floor of the nozzle trough 61 and is flush with the molten metal in the nozzle trough 61. It has been found that the device can be operated. In this manner, a very stable casting pool 68 state can be obtained, and if the triple point spout 96 is inclined downward at a sufficient angle, the stationary casting pool 68 can be obtained.
A surface can be obtained.

According to the illustrated example, the lower surface 100 of the nozzle trough 61 is recessed upward with the lower side of the floor 63 at a middle height, and a series of longitudinally spaced openings 101 are formed on the floor 63 along the highest part of the lower surface 100. And line them up. In nozzle operation, the reservoir generally stagnates on the lower surface 100, at which surface carbon monoxide bubbles are formed by a chemical reaction between the carbon in the nozzle refractory material and free oxygen or oxygen-containing compounds in the molten metal of the casting reservoir 68. It has been found to be very prominent. This bubble is surrounded by a depression in the lower surface 100 and has an opening 10.
1 and into the nozzle trough 61. In the nozzle trough 61, bubbles of carbon monoxide cannot be harmful.
If not vented in this manner or by any other control method, the bubbles will escape the nozzle sides and disturb the meniscus area of the casting sump 68.

The opening 101 is located near the lower side of the nozzle.
8 can also be an additional source of metal flow to prevent relatively large bubbles from stagnating and accumulating in the lower part of the nozzle. The openings 101 can be sized to allow sufficient flow of the metal stream to create a cleaning action that removes air bubbles from the surface before they form and grow to a significant size. The metal flow has the effect of removing excess carbon from the casting pool 68 near the lower side of the nozzle and actively suppressing the chemical reaction between carbon and free oxygen in the pool. According to calculations, there must be at least 4% carbon for the chemical reaction with free oxygen to proceed. Thus, if the carbon content can be kept below this level by the scavenging action, chemical reactions with carbon from the refractory material will be reduced.

The opening 101 must be small enough that the metal flow does not flow in preference to the main metal flow from the side opening 64, but must be large enough not to cause blockage. Round holes of 2 mm to 7 mm can achieve this result, with holes of 5 mm diameter being particularly preferred. A hole of this size seems to be able to perform a great deal of ventilation and metal flow down the nozzle. However, it should be understood that the size of the pores is selected primarily for bubble ventilation and, additionally, for metal flow down.

The openings 101 may be uniformly spaced along the nozzle, or may be concentrated at the nozzle end. Preferably, it is arranged so as not to be aligned with the molten metal flow 65. Thus, the molten metal stream 65 can be staggered adjacent to the nozzle outlet so as to be staggered. Opening 10
The size of 1 can be different along the nozzle,
For example, the opening 101 at the center of the nozzle where there is evidence of more air bubble formation than the nozzle end area can be made larger.

The opening 101 may be formed in a cylindrical shape having a uniform diameter. However, the opening 101 may be tapered downward and outward to generate a bubble funnel effect to promote bubble flow in preference to metal flow down. it can.

The side opening 64 has two metal supply nozzles 19.
It is important that it is provided at the inner end of the half, which ensures that the molten metal is sufficiently supplied in the vicinity of the central area of the nozzle and that skull formation in this area of the reservoir is reliably prevented.

The two outermost molten metal streams 65 flowing down from the distributor 18, ie, the molten metal streams 65 flowing down from the distributor 18.
The reservoir 88 receives the two molten metal flows 65 at both ends of the distributor 18 in the longitudinal direction. The two outermost outlet openings 52 of the distributor 18, i.e., the two outlet openings 52 at the longitudinal ends of the distributor 18, are a single outlet where each reservoir 88 impinges on the floor 91 just outside the inclined inner surface 92. Matched to receive metal flow. Molten metal floor 91
And diverges fan-like outward on the floor portion 91 to the triple junction outlet 96 via the triple junction injection passage 95, and the inward and downward inclined jet flow of the high-temperature molten metal is spread over the surface of the side weir and It is produced along the end of the casting roll 16 on the side of the roll gap 69. The triple point pouring is performed only by the shallow and wide molten metal reservoir of each reservoir 88, and the reservoir height of the reservoir 88 is limited by the height of the upper end 89 of the end wall 70. Reservoir 8
When 8 is full, the molten metal is at the upper end 89 of the end wall 70.
Can overflow into the nozzle trough 61 over the end wall 7
0 serves as a weir for controlling the depth of the reservoir 88 of the end forming portion 87. The depth of this reservoir is
5 is more than sufficient to provide a constant flow of molten metal to achieve a very uniform molten metal flow 65. This control flow is very important for properly forming the strip end. Excessive flow through the triple point injection passage 95 will cause bulges at the end of the strip, and too little will cause skulls and "snake egg" defects in the strip.

The bottom surface 98 of the end forming portion 87 is raised above the reservoir surface so as to prevent cooling of the reservoir surface at the triple point region. The bottom surface 98 is inclined outward and upward. This is preferable in order to prevent foreign matter such as slag from accumulating and clogging below the end of the metal supply nozzle 19. When such clogging occurs, the escape of gas and fumes from the reservoir is blocked and there is a risk of explosion.

The apparatus described above is for illustration only and, of course, the invention is not limited to these details. In particular, providing the triple point injection end forming portion in the metal supply nozzle 19 is a currently preferred nozzle shape, but is not essential to the present invention. Nozzle trough 6
Although it is preferred to provide a flow barrier wall 84 in 1 to reduce the kinetic energy of the molten metal flowing to the side openings 64, these barriers may be eliminated and another steady flow generating means may be provided in the nozzle. An upwardly trough-shaped nozzle lower surface is configured by closing the upper concave nozzle lower surface at both ends of the nozzle,
The ability to collect air bubbles vented through the bottom opening 101 can also be increased. Such modifications are possible within the scope of the invention which cover all novel features and combinations thereof described herein.

[0046]

As described above, according to the metal strip casting apparatus, the refractory nozzle for supplying molten metal to the casting pool and the continuous metal strip casting method of the present invention, the following excellent effects can be obtained.

The molten metal can be sufficiently supplied from the side opening to reliably prevent skull formation in the casting pool.

Air bubbles from the lower side of the nozzle can be discharged into the nozzle trough through the opening, and the air bubbles can be prevented from disturbing the meniscus area of the casting pool.

The opening at the bottom of the nozzle can be an additional source of metal flow to the casting pool near the underside of the nozzle and can prevent relatively large bubbles from stagnating and accumulating throughout the underside of the nozzle. In addition, by removing excess carbon from the casting pool near the lower side of the nozzle, the chemical reaction between carbon and free oxygen in the casting pool can be positively suppressed, and the chemical reaction of carbon derived from refractory materials can be reduced. Dissolution of the metal supply nozzle can be prevented.

[Brief description of the drawings]

FIG. 1 is an overall view showing a twin roll continuous strip casting apparatus constructed and operated according to the present invention.

FIG. 2 is a longitudinal sectional view of a main part of the twin-roll continuous strip casting apparatus shown in FIG. 1 including a metal supply nozzle configured according to the present invention.

FIG. 3 is a further longitudinal sectional view in a direction perpendicular to the section of FIG. 2;

FIG. 4 is an enlarged widthwise longitudinal sectional view of a portion adjacent to a metal supply nozzle and a casting roll.

FIG. 5 is a side view of a metal supply nozzle half.

FIG. 6 is a plan view of a metal supply nozzle half shown in FIG. 5;

7 is a longitudinal vertical sectional view of a half of the metal supply nozzle shown in FIG. 5;

FIG. 8 is a perspective view of a metal supply nozzle half shown in FIG. 5;

FIG. 9 is a perspective view in which the metal supply nozzle shown in FIG. 5 is turned upside down.

FIG. 10 is a view taken in the direction of arrows XX in FIG. 5;

11 is a view in the direction of arrows XI-XI in FIG. 7;

FIG. 12 is a view taken in the direction of the arrows XII-XII in FIG. 7;

[Explanation of symbols]

 Reference Signs List 16 casting roll 18 distributor 19 metal supply nozzle 61 nozzle trough 63 floor 64 side opening 68 casting pool 69 roll gap 101 opening

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor William John Folder Australia 2533 New South Wales Kiama Downs Kialama Avenue 34 (72) Inventor Paul Casar Australia 2519 New South Wales Borgouney Farrell Treat 24 (72) Inventor Keith Frederick Pitch Ford Australia 2527 New South Wales Albion Park Church Street 46

Claims (30)

[Claims] 1. A pair of parallel casting rolls forming a roll gap between each other, and formed of a refractory material of carbon extending along the roll gap above the roll gap and supplying molten metal to the roll gap. In a metal strip casting apparatus comprising an elongated metal supply nozzle and a distributor arranged above the metal supply nozzle and supplying molten metal to the metal supply nozzle, the metal supply nozzle extends in a roll gap longitudinal direction. The metal supply nozzle is provided with a side opening for flowing molten metal outward from the metal supply nozzle, and the nozzle bottom is provided with a nozzle under the nozzle at the bottom of the nozzle. A metal strip casting apparatus, comprising: an opening for directly communicating a side with the inside of a nozzle trough. 2. The metal strip casting apparatus according to claim 1, wherein the direct communication between the lower side of the nozzle and the inside of the nozzle trough is for controlling the release of bubbles from the lower side of the nozzle. 3. The method according to claim 1, wherein the metal flow is allowed to descend through an opening at the bottom of the nozzle, thereby preventing a stagnation of the casting pool below the nozzle.
Or the metal strip casting apparatus according to 2. 4. The metal strip casting apparatus according to claim 3, wherein the opening at the bottom of the nozzle is for preventing excess carbon in the casting pool near the lower side of the nozzle from causing melting of the metal supply nozzle. 5. The metal strip according to claim 1, wherein the opening at the bottom of the nozzle is for venting upward from below the nozzle to prevent bubbles from being generated in the upper region of the casting pool. Casting equipment. 6. The metal strip casting apparatus according to claim 1, wherein the openings at the bottom of the nozzle are spaced apart along the longitudinal direction of the nozzle. 7. The metal strip casting apparatus according to claim 5, wherein the lower side of the nozzle is recessed upward, and the opening at the bottom of the nozzle is arranged in a line along the highest portion of the lower side recessed above the nozzle. 8. The metal strip casting apparatus according to claim 7, wherein both ends on the lower side of the upwardly concave nozzle are closed to form a lower side of the nozzle having a trough shape upward. 9. The metal strip casting apparatus according to claim 1, wherein the opening at the bottom of the nozzle is a round hole formed in the floor of the nozzle trough. 10. The metal strip casting apparatus according to claim 5, wherein the opening at the bottom of the nozzle is a hole tapered downward and outward to promote upward ventilation prior to metal flow down. . 11. A refractory body made of a refractory material made of carbon forming an upwardly open elongated nozzle trough for receiving the molten metal, a side opening for flowing the molten metal from a metal supply nozzle to a side outward, A refractory nozzle for supplying molten metal to a casting pool, comprising: an opening at the bottom of the nozzle for directly communicating the lower side of the nozzle with the inside of the nozzle trough. 12. A refractory nozzle for supplying molten metal to a casting pool according to claim 11, wherein the direct communication between the lower side of the nozzle and the inside of the nozzle trough is for controlling the release of bubbles from the lower side of the nozzle. . 13. A refractory for supplying molten metal to a casting pool according to claim 11, wherein the opening at the bottom of the nozzle allows the metal stream to descend through the opening and prevents stagnation of the casting pool below the nozzle. nozzle. 14. A descent of metal flow through the opening at the bottom of the nozzle to prevent excess carbon in the casting pool near the underside of the nozzle from causing melting of the refractory nozzle.
A refractory nozzle for supplying molten metal to the casting reservoir according to claim 13. 15. The casting pool according to claim 11, wherein an opening at the bottom of the nozzle provides ventilation from below the nozzle into the nozzle trough to prevent the formation of bubbles in the upper region of the casting pool. Refractory nozzle for supplying molten metal. 16. A refractory nozzle for supplying molten metal to a casting pool according to claim 11, wherein the openings at the bottom of the nozzle are spaced apart along the longitudinal direction of the nozzle. 17. The method according to claim 15, wherein the lower side of the nozzle is recessed upward and the opening at the bottom of the nozzle is arranged along the uppermost portion of the upper side of the nozzle recessed upward. Refractory nozzle to supply. 18. An upwardly trough-shaped lower nozzle is formed by closing both ends of a lower side of a nozzle which is recessed upward.
A refractory nozzle for supplying molten metal to the casting reservoir according to claim 7. 19. The refractory nozzle according to claim 11, wherein the opening at the bottom of the nozzle is a round hole formed in the floor of the nozzle trough. 20. The nozzle according to claim 15, 17 or 18, wherein an opening at the bottom of the nozzle is formed as a hole tapered downward and outward, and an upward ventilation is promoted prior to a metal flow drop through the hole.
A refractory nozzle for supplying a molten metal to the casting reservoir according to claim 1. 21. A molten metal is introduced between casting rolls through an elongated metal supply nozzle disposed above and along the roll gap between a pair of cooled casting rolls, and the molten metal is supported above the roll gap. In a continuous metal strip casting method in which a metal casting pool is formed and a casting roll is rotated to cast a solidified strip fed downward from a roll gap, a metal feed nozzle extends in a longitudinal direction of the roll gap to receive molten metal. Consisting of an elongated nozzle trough that opens upward, the metal supply nozzle has a side outlet that allows molten metal to flow outward from the metal supply nozzle, and an opening at the bottom of the nozzle that directly communicates the lower side of the nozzle with the inside of the nozzle trough. A continuous casting method of a metal strip, comprising: 22. The continuous metal strip casting method according to claim 21, wherein the direct communication between the lower side of the nozzle and the inside of the nozzle trough is for controlling the release of bubbles from the lower side of the nozzle. 23. The continuous metal stop casting method according to claim 21 or 22, wherein the metal flow can descend through an opening at the bottom of the nozzle to prevent stagnation of the casting pool below the nozzle. 24. The method of claim 23, wherein the opening at the bottom of the nozzle is for preventing excess carbon in the casting pool near the underside of the nozzle from causing melting of the metal supply nozzle. . 25. The metal strip according to claim 21, wherein the opening at the bottom of the nozzle is for venting upward from below the nozzle to prevent bubbles from being generated in the upper region of the casting pool. Continuous casting method. 26. The metal strip continuous casting method according to claim 21, wherein the openings at the bottom of the nozzle are spaced apart along the longitudinal direction of the nozzle. 27. The continuous metal strip casting method according to claim 25, wherein the lower side of the nozzle is recessed upward, and the opening at the bottom of the nozzle is arranged along the highest portion of the lower side recessed above the nozzle. . 28. The continuous metal strip casting method according to claim 27, wherein the lower end of the nozzle, which is formed into an upper trough, is formed by closing both ends of the lower side of the nozzle which is concave upward. 29. The continuous metal strip casting method according to claim 21, wherein the opening at the bottom of the nozzle is a round hole formed in the floor of the nozzle trough. 30. The continuous casting of a metal strip according to claim 21, 27 or 28, wherein the opening at the bottom of the nozzle is a downwardly tapered hole to promote upward ventilation prior to metal flow down. Method.