JPH0284233A - Continuous casting apparatus for cast strip - Google Patents

Abstract

PURPOSE:To produce a cast strip without any casting fin by thermal-spraying or coating refractory having low wettability to molten metal on surface of a weir regulating width direction of pouring basin part and surface part of a metallic belt contacting with the weir. CONSTITUTION:The side weir 11 forms the refractory layer 14 at the bottom face contacting with the metallic belt 1 and neighborhood thereof. The refractory layer 17 is formed at the surface part of the metallic belt 1 contacting with the side weir 11, too. As material of the refractory, the refractory having low wettability to the molten metal, such as zirconia, is used. The molten metal poured into the pouring basin part 5 has large contacting angle to the refractory layers 14, 17, and invasion into gap 15 between the metallic belt 1 and the side weir 11, is restrained. By this method, penetration developing between the side weir and the metallic belt is restrained and the cast strip without any casting fin is produced and as the separatibility from continuous casting machine is good, the casting condition can be stabilized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a continuous casting apparatus that produces thin slabs by partitioning a pool with a metal belt, such as a single belt system or a twin belt system.

[Conventional technology]

BACKGROUND ART Recently, a continuous casting method has been attracting attention, in which a thin slab having a thickness close to the final shape is directly produced from molten metal such as molten steel. When this method is used, the hot rolling process can be simplified or omitted, and the rolling required to form the final shape can be light, so that the process and equipment can be simplified.

A single-belt method, which is one of such continuous casting methods for sake meat slabs, has been proposed in, for example, Japanese Patent Laid-Open No. 155247/1983. In this method, for example, as shown in Fig. 3, an endlessly running metal bell (1) is passed between an upstream pulley 2 and a downstream pulley 3, and the upstream pulley 2 is placed at a lower position than the downstream pulley 3. to be located. As a result, the upper side of the metal belt 1 runs obliquely upward as shown by the arrow. Therefore, the upper surface of the metal belt 1 is partitioned by a rear dam 4 in the width direction to form a pool 5.

Molten metal 7 is injected into this pool 5 from an intermediate container 6 such as a tundish through an injection nozzle 6a. Heat is removed from the injected molten metal 7 via the metal belt 1 by a cooling device 8 arranged on the back side of the metal belt 1. As a result, a solidified shell 9 is formed on the upper surface of the metal belt 1. This solidified shell 9 is transported in the direction of the arrow as the metal belt 10 runs, and during this transport stage it grows.
A thin slab 10 having a predetermined thickness is taken out from the sump 5.

[Problem to be solved by the invention]

When viewed from the running direction of the metal belt 1, the hot water reservoir portion 5 is
As shown in FIG. 4(a), both ends are side j! 11
It is separated by 1a and llb. This side weir 11
a.

11b, in order to withstand the surface pressure from the metal belt I,
At least the surface facing the metal belt 1 is made of metal. Therefore, the molten metal 7 is highly wetted, and the molten metal 7 easily enters between the side 1t111a, llb and the metal belt 1, causing a hot water pourer 12. Since the hot water jug 12 solidifies while being integrated with the solidification well 9, it remains as flash 13 at both ends of the obtained thin slab 10. This casting burr 13 deteriorates the shape of the thin slab 10 and also causes the metal belt 1 and the side I [
This prevents the thin slab 10 from detaching from the I 11. As a result, the casting operation becomes unstable and the quality of the product obtained also deteriorates.

This problem occurs not only in the single-belt type shown in FIG. 3 but also in a twin-belt type continuous casting apparatus in which the pool 5 is partitioned from both sides by metal belts.

Therefore, the present invention suppresses the occurrence of boiling water by coating or spraying at least the surface of the side weir on the side in contact with the metal belt or the surface portion of the metal belt in contact with the side weir with a material with low wettability. The purpose is to enable casting work under stable conditions and to produce thin slabs with excellent shape characteristics.

[Means to solve the problem]

In order to achieve the object, the thin-wall continuous cast slab casting apparatus of the present invention has a weir that regulates the width direction of the sump formed in contact with the metal belt in a single-belt type or twin-belt type continuous casting apparatus. It is characterized in that the surface and/or the surface portion of the metal belt in contact with the weir is coated or thermally sprayed with a refractory material that has low wettability with the molten metal poured into the sump.

[Function] Hereinafter, the features of the present invention will be specifically explained along with the function with reference to the drawings.

FIG. 1 shows a sump during the production of thin slabs using the side weir according to the invention.

In addition, in the same figure, parts corresponding to those shown in FIG. 3 are indicated by the same reference numbers.

Further, although FIG. 1 shows a single-belt type continuous casting apparatus, the present invention is similarly applicable to a twin-belt type continuous casting apparatus.

On this side I'll I, a refractory layer 14 is formed on the bottom surface in contact with the metal bell 1 and in the vicinity thereof. Also,
A refractory layer 17 is similarly formed on the surface portion of the metal belt 1 in contact with the side weir 11. The materials forming the refractory z14 or 17 include zirconia, alumina,
Refractories with low wettability to molten metal, such as concrete and magna, are used. The molten metal injected into the pool 5 has a large contact angle with the refractory layer 14 or 17, and is prevented from entering the gap 15 between the metal belt 1 and the side weir 11. On the other hand, when the refractory layer 14 or 17 is not applied, the gold of the steel etc. that constitutes the side weir 11, @
Due to the high wettability of the material 4, the molten metal flows onto the side i[1
It spreads along the surface of 11 and largely invades the gap 15,
This is the cause of the Paris 13 outbreak mentioned above.

Refractory layer 14. 17 is coated on the surface of side 111 and side II by appropriate means such as coating or thermal spraying.
Either one of the surface parts of the metal belt 1 in contact with 11,
Or it is formed on both sides. The thickness of the refractory layer 14.17 is preferably maintained at about 2 to 200 μm. If this film thickness is less than 2 μm, the side i[111 and the metal belt 1 are likely to be peeled off when they rub against each other, and the refractory layer 14
Or the effect of No. 17 cannot be sustained for a long time. Moreover, when the film thickness of the refractory layer 17 exceeds 200 μm, the metal belt 1 tends to peel off due to bending strain that occurs when it passes through the upstream pulley 2 and the downstream pulley 3.

Further, the inner surface of the side wall is lined with a heat insulating refractory 16. This heat-insulating refractory 16 suppresses heat removal from the molten metal through the side l[111] and prevents the formation of a[shell] along the inner surface of the side weir 11. However, if this heat-insulating refractory 16 comes into direct contact with the metal belt, the heat-insulating refractory 16 is likely to be damaged due to the surface pressure from the metal belt 1. It is in the upper position. Therefore, the inner surface of the side weir 11 located below the heat insulating refractory 16 comes into direct contact with the molten metal in the sump 5. Therefore, in order to avoid direct contact between the side weir 11 and the molten metal and to prevent a solidified shell from growing there, a refractory layer 14 can also be applied to the lower part of the inner surface of the side weir 11.

In this way, according to the present invention, since no hot water is generated in the gap 15 between the metal belt 1 and the side j [11, the solidified felt 9 or the thin slab 10 formed on the metal belt 1 is detached from the metal belt 1 without any trouble and is conveyed to the subsequent process. Moreover, the shape of the thin slab lO itself becomes good.

〔Example〕

Using a single-belt continuous casting machine, molten steel with a common steel composition and a temperature of 1590°C is injected into the pool, and a plate width of 3
A thin slab 10 having a thickness of 12 m and a thickness of 12 m was cast at a casting speed of 16 m/min. At this time, the side weirs 11 that partitioned both ends of the pool 5 were made of heat-resistant steel as a base material. An alumina-based heat-insulating refractory material 1G was formed on the inner surface of this side weir 11. In addition, the bottom surface and lower inner surface of the side weir 11 and the surface portion of the metal belt 1 facing the side weir 11 have exposed metal;
Refractory layers 14 and 17 formed of various ceramics were used.

These side weirs 11 are placed on the upper surface of the metal belt 1,
Casting was performed with an artificial gap of about 0.5 s provided between the metal belt 1 and the side weir 110, and the length of the casting flash 13 generated at both ends of the obtained thin slab lO was measured. FIG. 2 is a graph showing the measurement results.

As is clear from FIG. 2, when the side weir 11 and metal belt 1 without the refractory layer 14, 17 are used,
A big blowout occurred on March 3. This is gold 1 @ belt 1
This is considered to be due to the molten metal penetrating deeply into the gap 15 between the side j[111] and the side j[111. On the other hand, when using the side weir 11 and metal belt in which the refractory layer 14.17 is formed by thermally spraying ceramics such as zirconia, alumina, or silica to a thickness of 50 μm, the cast burr is approximately 1 + am. It was kept below.

In this way, the thin slab 10 with reduced casting burrs due to the refractory layers 14 and 17 could be easily separated from the metal belt 1 and transported to the subsequent process. Furthermore, since the number of both ends to be trimmed after rolling could be reduced, the yield improved by about 1%.

〔Effect of the invention〕

As explained above, in the present invention, at least the surface of the side weir in contact with the metal belt and/or the surface portion of the metal belt in contact with the side weir is thermally sprayed or coated with a refractory having low wettability to molten metal. ing. Therefore, the contact angle between the side weir and the molten metal is large, suppressing the formation of hot water between the side weir and the metal belt, and making it possible to produce thin slabs with small or no flash burrs. becomes. The thus obtained thin-walled slab has good removability from the continuous casting machine, so casting conditions are stabilized. Moreover, the yield when cutting out products by trimming after rolling a thin slab is also improved.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a state in which a thin slab is produced by a single belt method using the side weir of the present invention, and FIG. 2 is a graph specifically showing the effects of the present invention. On the other hand,
FIG. 3 is a schematic diagram showing a conventional single-belt type continuous casting apparatus, and FIG. 4 is a diagram for explaining the problems thereof. 1: Metal belt 2: Upstream pulley 3: Downstream pulley 4: Rear weir 5: Reservoir 6: Intermediate container 5a + injection nozzle 7: Molten metal 8: Cooling device
9゛ Solidified shell 10: Thin slab 11
．． lla, llb: Side weir 12: Boiler 13: Cast burr 14: Refractory layer 15: Gap 16: Heat insulating refractory 17: Refractory layer

Claims (1)

[Claims] 1. In a single-belt type or twin-belt type continuous casting device, the above-mentioned 1. An apparatus for continuous casting of thin-walled slabs, characterized by coating or thermal spraying with a refractory material that has low wettability with molten metal injected into a pool.