JPH0763812B2 - Belt Deformation Prevention Method in Metal Strip Continuous Casting Machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to the production of a metal ribbon by cooling and solidifying a molten metal on a running belt or between a pair of belts. It relates to a method of preventing deformation.

[Conventional technology]

Recently, from molten metal such as molten steel, several mm to several tens, which is close to the final shape
Attention has been paid to a continuous casting method for directly producing a ribbon having a thickness of about mm. According to this method, a hot rolling process as in the past is not required or can be greatly simplified, so that the process and equipment can be simplified.

A belt method is one of the continuous casting methods. In this method, for example, a molten metal pool formed on an endless running belt is cooled and solidified by removing heat from the molten metal poured through the belt, and the generated shell is accompanied by the running of the belt. The metal ribbon is manufactured by sending it out from the pool. In this belt method, the molten metal is cooled from one direction and the surface opposite to the belt is open. Therefore, there are less restrictions on the arrangement of the nozzles that supply the molten metal from the container such as a tundish to the molten metal pool on the belt.

The present inventors have developed a casting device in which a weir that partitions the side surface of the molten metal pool can be moved in this belt system, and filed as Japanese Patent Application No. 60-155247.

FIG. 3 shows the single belt type apparatus proposed in this prior application.

In this device, a metal belt 1 is provided with a pair of pulleys 2
It is hung on a and 2b and runs on an endless track. By holding one pulley 2a high, the endless track of the belt 1 rises toward the pulley 2a. Around the belt 1, a plurality of heat resistant blocks 3 connected by a chain or the like are arranged,
These heat resistant blocks 3 move in synchronization with the running of the belt 1.

The heat-resistant block 3 serves as a side weir 5 that partitions the side of the pool 4 at the upper portion where the belt 1 travels in a straight line. On the other hand, a fixed weir 6 is provided behind the hot water pool 4. As a result, the basin 4 is formed in which only the traveling direction of the belt 1 is open. Molten metal 8 is poured into the pool 4 from a pouring device 7.

The molten metal 8 poured is removed from heat by a cooling device 9 arranged on the back surface of the belt 1, cooled and solidified into a solidified shell 10. The solidified shell 10 is conveyed rightward in FIG. 3 as the belt 1 moves. Since the heat removal is continued in the course of this transportation, the solidified shell 10 grows into a thin strip 11 having a predetermined thickness and is sent out from the molten metal pool 4.

This thin strip 11 is then rolled by a pressure roll 12 to a target plate thickness, and is wound up as a thin plate coil 14 by a winding device 13.

[Problems to be solved by the invention]

In this way, when the molten metal poured into the pool 4 is formed on the surface of the belt 1 and the solidified shell 10 is generated and grown from the molten metal, as shown in the plan view of FIG. The surface of the belt 1 in contact with the reservoir 4 is 300 to 400 ° C., and the average temperature in the thickness direction of the belt 1 is as high as 180 to 250 ° C. On the other hand, the coolant sprayed from the cooling device 9 toward the back surface of the belt 1 is in contact with the pool 1 of the belt 1.
Not only on the back side of, but also on the entire back side. Therefore, the back surface of the belt 1 excluding the portion in contact with the basin 4 is kept at a low temperature of 70 to 100 ° C. by the refrigerant. as a result,
A large temperature fluctuation occurs in the width direction of the belt 1, and in particular, the temperature difference between the basin 4 and the side dam 5 in the thickness direction average temperature of the belt 1 becomes large. This temperature fluctuation causes abnormal deformation and buckling of the belt 1. Therefore, the flatness of the belt 1 is impaired, and the shape of the obtained ribbon 11 is not stable.

Further, problems such as abnormal deformation and buckling of the belt are not limited to the single-belt type continuous casting machine shown in FIG. 3, but also occur in the twin-belt type continuous casting machine.

Therefore, it is an object of the present invention to prevent abnormal deformation and buckling of the belt due to such temperature fluctuations, and to produce a metal ribbon having excellent surface properties and shape characteristics.

[Means for solving problems]

In order to achieve the object, a belt deformation preventing method of the present invention is to cool and solidify a molten metal poured into a hot water pool portion provided on a running belt or between a pair of belts. In a metal thin strip continuous casting machine for continuously casting a strip, in order to prevent the deformation of the belt, a side dam or a short side mold partitioning both sides of the molten metal pool is run in the same direction as the belt, and the surface of the belt. The surface of the side weir or the short-side mold that comes into contact with is heated before reaching the hot water pool.

〔Example〕

Hereinafter, the features of the present invention will be specifically described by way of examples with reference to the drawings.

FIG. 1 shows an embodiment in which the present invention is applied to a single belt type continuous casting machine. In FIG. 1, components corresponding to the members shown in FIG. 3 are designated by the same reference numerals. Also, since this continuous casting apparatus is an improved version of the apparatus shown in FIG. 3, except for the portion shown in FIG.
Basically, it has the members shown in FIG.

In this continuous casting apparatus, the belt 1 is run from the lower pulley 2b toward the upper pulley 2a, and the molten metal pool 4 is provided on the belt 1. The solidified shell 10 produced by cooling and solidifying the molten metal supplied to the basin 4 is conveyed rightward in FIG.

Around the belt 1, as in the case of FIG. 3, a plurality of connected heat-resistant blocks 3 serving as side dams 5 are running. The running speed of the heat resistant block 3 is preferably synchronized with the running speed of the belt 1 so that the side weir 5 is left stationary on the running belt 1.

A heater 15 is provided in the middle of the transport path of the heat resistant block 3. The heater 15 is directed to the lower surface of the side dam 5 that comes into contact with the belt 1 in the basin 4. The heat-resistant block 3 is preheated to 300 to 400 ° C. by the heater 15. In this state, when it is sent to the basin 4,
The temperature fluctuation in the width direction of the belt 1 caused by the heat received by the molten metal in the molten metal pool 4 becomes small. That is, the central portion of the belt 1 is heated by the heat retained by the molten metal, but both end portions are heated by the heat resistant block 3, so that the temperature difference between the central portion and the both end portions can be suppressed within 50 ° C.

As the heater 15, various means such as electric heating, gas heating, and induction heating can be adopted. This heater 15 is on the front side where the belt 1 and the side weir 5 are in contact with each other,
It is desirable to install it as close as possible to. This is because if the belt 1 and the side dam 5 are heated after they come into contact with each other, the belt 1 is likely to be excessively heated, and if the distance from the pool 4 is increased, the heat dissipation from the heat resistant block 3 to the atmosphere and the heat resistant block 3 are caused. This is a result of considering that the temperature of the surface of the heat-resistant block 3 in contact with the belt 1 is lowered due to the thermal diffusion inside.

Since the lower surface of the side dam 5 that contacts the belt 1 can be heated by the heater 15, the belt temperature can be stabilized as compared with the method of directly heating the belt 1. That is, since the heat capacity of the belt 1 is smaller than that of the heat resistant block 3, the temperature of the belt 1 immediately decreases when the belt 1 and the heat resistant block 3 contact each other when the belt 1 alone is heated and the heat resistant block 3 is not heated. . Also,
If the belt 1 and the heat-resistant block 3 are heated at the same time, the temperature of the belt 1 may rise excessively because the heat capacity of the belt 1 is small.

The following table shows how the deformation of the belt 1 was suppressed by heating the heat resistant block 3 by the heater 15. The amount of deformation of the belt 1 is an average value of the maximum height and the minimum height along the width direction. Further, as the belt 1, a steel strip having a width of 500 mm and a thickness of 1 mm was used, and a molten metal having a normal steel composition and a temperature of 1570 ° C. was poured into the basin 4 having a width of 300 mm.

As is apparent from Table 1, the preheating of the heat resistant block 3 suppresses the belt 1 from being deformed in the direction perpendicular to the surface of the belt 1. Therefore, the solidified shell 10 generated and grown in the pool 4 formed on the belt 1 became flat. As a result, the obtained ribbon 11 had excellent surface properties without vertical wrinkles or irregularities.

FIG. 2 shows an embodiment in which the present invention is applied to a twin belt type continuous casting machine.

In this example, the pair of belts 21a, 21b are running in opposite directions, and a plurality of connected heat-resistant blocks 23 to be short-side molds 22 in the gaps in which these belts 21a, 21b face each other.
Is being sent. This short side mold 22 and belts 21a, 21b
A casting space partitioned by is formed between the belts 21a and 21b. Then, molten metal is injected into the casting space from above and is generated by cooling through the belts 21a and 21b.
The solidified shell that has grown is carried out as a ribbon from below.

Then, in the middle of the conveyance path of the heat resistant block 23, the belt 21
A pair of heaters 24 are arranged on both sides of the heat resistant block 23 so as to preheat the surface of the short-side mold 22 that contacts the a and 21b. By preheating the heat-resistant block 23 with this heater 24, the belt in the casting part is sewn similarly to the example of FIG.
It was possible to suppress temperature fluctuations along the width direction of 21a, 21b.

〔The invention's effect〕

As described above, in the present invention, the surface of the side dam or the short side mold that is fed into the basin is contacted with the belt in advance, so that the belt is made of molten metal in the basin. It suppresses that the central part is heated and the temperature difference between the both ends becomes large. Therefore, the thermal stress applied to the belt is relaxed, and abnormal deformation and buckling of the belt are prevented. Therefore, the belt can be used for a long period of time, and the shape characteristics of the cast metal ribbon can be improved.

[Brief description of drawings]

FIG. 1 shows an embodiment in which the present invention is applied to a single belt type continuous casting machine, and FIG. 2 shows an embodiment in which the present invention is also applied to a twin belt type continuous casting machine. On the other hand, FIG. 3 shows a single belt type continuous casting machine previously proposed by the present inventors,
FIG. 4 is a diagram for explaining a problem that occurs in the belt in the continuous casting machine.

Claims (1)

[Claims] 1. A metal strip continuous casting machine for continuously casting a metal strip by cooling and solidifying a molten metal poured in a pool of water provided on a running belt or between a pair of belts, In preventing the deformation of the belt, the side dam or the short side mold that partitions the both sides of the hot water pool is run in the same direction as the belt, and the surface of the side dam or the short side mold that contacts the surface of the belt. A method for preventing deformation of a belt in a continuous metal ribbon casting machine, characterized in that heating is performed before reaching the pool.