JPH0342153A - Continuous casting machine for cast strip - Google Patents

Abstract

PURPOSE:To easily develop solidified shell on long side mold and to smoothly draw a cast strip downward by making heat conductivity in the long side mold material at part adjacent to both side edge parts of short side mold equal or more to or than the heat conductivity the main material constituting both side edge parts of the short side mold. CONSTITUTION:The side edge parts 12 of short side mold 5 is made of copper and the material of belt 2 is made of copper showing the heat conductivity equal to the heat conductivity in the short side mold 5. By this method, the solidified shell on the sort side mold 5 is integrally developed with the solidified shell formed on the long side mold, and sticking or abnormal growth on the short side mold are eliminated and breakout is eliminated. The short side is made to smoothly draw downward and the cat strip having excellent quality can be stably obtd.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a continuous casting machine for thin plate slabs that forms while cooling 7 seconds of hot water, and is particularly suitable for stably obtaining slabs of excellent quality. Concerning a continuous thin plate slab casting machine.

[Conventional technology]

There is a continuous casting machine with a continuous rotation on the long side as a device that continuously forms thin plates, but a continuous casting machine with a narrowing type twin belt is
Since it is known to be economically superior to conventional slab continuous casting machines, the drawing type twin-belt continuous casting machine will be described here as a representative example of the prior art. However, the present invention applies not only to the continuous casting machine described here, but also to continuous casting machines in general as devices that continuously form all thin plates.

In this drawing-type twin-belt continuous casting machine, the surface area of the molten metal in the pouring section is wide, and it becomes narrower as it goes downward, and the plate thickness is determined by the gap at the narrowest part. The molten metal is cooled and shaped as the mutually opposing cooling bodies move or rotate. The cooling body faces the long side of the slab to be shaped, so it is called a long side mold. A side dam is provided between the ends of this long-side mold to prevent spillage of the molten metal, and this side dam is called a short-side mold because it faces the short side of the slab to be formed. Short side molds are usually fixed and do not move like long side molds. Therefore, the short side mold is made of a material that has little cooling effect.

Refractories are considered to be the most suitable material. The reason why the cooling effect is eliminated in this way is that once the slab is cooled, it cannot be pulled out downward. When the short-side mold is made of a refractory material, it is preferable to use a different material on the side edges of the short-side mold as a countermeasure against damage caused by contact with the long-side mold. As the belt material, iron-based materials are used for boat fishing.

Incidentally, a related continuous casting machine for thin plate slabs of this type is disclosed, for example, in Japanese Patent Application Publication No. 1988-9903.

[Problem to be solved by the invention]

The problem with such a configuration is whether or not the slab can be successfully pulled downward.

Since the short-side mold is fixed, the solidified shell formed on the short-side mold basically does not move. In other words, in such a continuous casting machine, the solidified shell formed in the short-side mold is integrated with the solidified shell formed in the long-side mold, so that the slab can be successfully drawn downward.

Since the short side mold is fixed, a solidified shell is easily formed. In contrast, long-sided molds are generally moving at high speeds. Therefore, it is usually difficult to form a solidified shell near the meniscus.

In other words, since a solidified shell is formed only on the short side mold in the vicinity of the meniscus, the solidified shell formed on the short side mold is not connected to the solidified shell formed on the moving long side mold. . Therefore, the solidified shell formed on the short side mold grows larger and larger while being fixed on the short side mold, and these shells are transferred to the long side mold that is moving in synchronization with the moving cooling body. It is left on the short side mold in a state separated from the formed solidified shell. As a result, the short side shell of the slab, which is moving in synchronization with the cooling body, is sent out of the mold without being formed.
There is a problem that a stable VI construction cannot be realized due to the problem of B-molten metal flowing out of the mold, and a desired slab cannot be obtained.

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, it is an object of the present invention to ensure that the solidified shell formed in the short side mold part is integrated with the solidified shell formed in the long side mold part so that the slab can be smoothly moved downward. It is an object of the present invention to provide a continuous casting device that stably obtains slabs of excellent quality by having a structure that allows the casting to be drawn.

[Means to solve the problem]

The above purpose is to make the thermal conductivity of the long side mold material of at least the portion adjacent to the twill portions on both sides of the short side Wi'12 of the long side mold to a value equal to or higher than the thermal conductivity of the main material constituting both side edges of the short side mold. This is achieved by

[Effect]

In this case, by making the thermal conductivity of the long side mold material adjacent to both side edges of the short side mold exhibit a value equal to or higher than the thermal conductivity of the main material constituting the both side edges of the short side mold, Cooling of the long-side mold is promoted, and a solidified shell is easily formed on the long-side mold. As a result, a solidified shell is quickly formed on the discarded long-side ladder mold adjacent to both side edges of the short-side mold, and the solidified shell is integrated with the solidified shell formed on the short-side mold. As a result, since the slab can be pulled out downward, it is possible to stably obtain slabs of excellent quality.

〔Example〕

Next, embodiments of the present invention will be described based on the drawings.

First, Fig. 1 shows the configuration of a narrowing double-belt continuous casting machine. The twin-belt continuous casting machine is equipped with a pair of two belts (long side molds) 2.2 facing each other, and a short side mold (side dam) made of high melting point refractory material 3 between the two ends.
5 are provided respectively. Belt 2 is roller 6.7
, 8, is floated and supported by a hydrostatic bearing type pad 1, and rotated in the casting direction (downward). Tension is applied to the belt 2 by pulling the roller 7 from the cylinder 10 via the bracket 9.

In this way, the slab 11 is continuously shaped while being cooled by the movement of the belt 2.

In order to examine the effects of the present invention, the side edge 12 of the short side mold (side dam) 5 was made of copper, and the material of the belt 2 was made of steel having a thermal conductivity lower than that of the short side mold. As an example of the invention, two types of copper molds having thermal conductivity equivalent to that of the short side mold were prepared, continuous casting was performed, and castability was examined.

In addition, in order to monitor the pro-solidification behavior of the mold, a temperature detection sensor was installed near the molten metal contact side of the short mold side edge.
The temperature near the short side of the mold in contact with the mold was detected to monitor the pro-solidification behavior of the mold.

Thereby, it is possible to grasp the solidified shell formation status in the short side mold portion. FIGS. 2A and 2B are schematic diagrams of the short-side mold portion of the twin-belt continuous casting machine shown in FIG. 1, viewed from the molten metal side. (a) is a plan view, and (b) is a side view. The temperature detection sensors 4 are provided in side edge portions 12 made of copper provided on both side edges of the short side mold (side dam) 5, at respective positions 0.5 mm+ from the hot water level. The locations where temperature detection sensors are installed are indicated by black dots. The circled number is the number of the temperature detection sensor 4. Here, in the case of normal casting, the temperature detection sensor 4
The smaller the number, the higher the temperature. Furthermore, in the case of stable casting, each temperature should have small changes.

In Fig. 1, the belt 2 is made of steel, the upper width of the molten metal holding area is 20Qmm, the narrowest part of the lower molten metal holding area is 30mm, and a steel thin plate with a width of 800nm is attached at 12m/mi.
As an example of the temperature distribution detected by the temperature detection sensor shown in Fig. 2 when continuously withdrawing at a speed of n,
, ■The results are shown in Figure 3. The temperature of each sensor consists of small peaks, and a detection temperature reversal phenomenon occurs.

Here, the presence of small peaks in the sensor temperature indicates that the solidified shell on the side edge of the short side mold (side dam) 5 does not move smoothly and is stuck. In other words, when the temperature is decreasing, the solidified shell is not moving but is solidifying and growing thickly. Furthermore, the area where the temperature is rising is because the solidified shell has fallen off and the molten metal has entered that area. in this way,
The sensed temperature inversion phenomenon occurs as a result of the solidified shell sticking and falling off in a disorderly manner. In part A of FIG. 3, the temperatures of both ■ and ■ suddenly drop, and then rise rapidly. This shows the result of the solidified solidified shell growing significantly and then breaking out. When the belt 2 is made of steel, the short side mold (
This is because the solidified shell on the side dam) 5 separates from the solidified shell formed on the long side mold, and sticks or grows abnormally large on the short side mold.

Next, according to the present invention, the belt 2 was made of copper and cast in the same manner as described above. In that case, ■,
Figure 4 shows the temperature distribution results detected by the temperature detection sensor (2). Unlike Figure 3.

Each temperature is stable, and no reversal phenomenon of detected temperatures occurs. Also, there are no more breakouts.

The reason why the temperature results are as shown in Figure 4 is that the solidified shell on the short side mold (side dam) 5 grows together with the solidified shell formed on the long side mold, and it sticks on the short side mold. Or this is because abnormal growth has disappeared. In addition, this is achieved by making the material of the long side mold in contact with both edges of the short side mold to a material that has a thermal conductivity equal to or higher than the thermal conductivity of the main material constituting the side part of the short side mold. , I on both sides of the short side mold
This is because a solidified shell was formed at an early stage on the waste long-side mold that was in contact with the mold, and that solidified shell was integrated with the solidified shell formed on the short-side mold. the result,
The slab was now able to pass through the bow successfully, and slabs of excellent quality could be stably obtained. The composition of the steel material is C: 0.04%, Mn: 0.30% in weight%.
, pro.

023%, S; 0.016%, AΩ; 0.042
% was used.

In the embodiment, the belt is made of copper, but only the portion adjacent to the short side mold may be made of the same material.

Plating, thermal spraying, cladding,
Materials subjected to surface treatments such as sputtering films, CVD films, and ion dynamic mixing also fall under the scope of the present invention. On the other hand, if only the surface portion is subjected to surface treatment to the extent that it does not contribute to the formation of a solidified shell, the main constituent material of the belt is subject to the present invention. In addition, the thermal conductivity of the short-side mold material is the value of the main component material, and it is not related even if the thermal conductivity of only the surface part is changed by surface treatment. It goes without saying that the thermal conductivity of the surface-treated portion is relevant to the present invention if it affects shell formation.

Although the short-side mold is arcuate in the embodiment, it does not necessarily have to be arcuate, and the effects of the present invention are not affected even if it is linear or quadratic curved.

In the embodiment, a belt-type continuous casting machine in which the long-side mold is a belt has been described, but the long-side mold is not limited to the belt type, and may be a twin roll type, a track plate, or the like.

The present invention is not only applicable to the downward drawing continuous casting machine described in the embodiments, but also to horizontal continuous casting machines and continuous casting machines of various angles located between the downward drawing method and the horizontal continuous casting machine. It is also applicable to

In the embodiment, the high melting point refractory material 3 is used for the short side mold 5, but a high melting point refractory material for heat retention may be applied to the relevant portion by thermal spraying or the like, overlaying or bonding. Alternatively, the high melting point refractory 3 may be omitted and the corresponding portion may be made of metal, organic or inorganic material, or amorphous material.

Although the embodiment uses a narrowing down method, it does not necessarily have to be a narrowing down method, and the effects of the present invention are not affected by a method that does not narrow down.

〔Effect of the invention〕

According to the present invention, a solidified shell is formed at an early stage on the movable long-side mold that is in contact with the traverse portions on both sides of the short-side mold, and
The solidified shell is integrated with the solidified shell formed on the short side mold, and as a result, the solidified shell is formed on the short side of the mold. This has the effect of making it possible to stably obtain slabs of excellent quality because the steel can be successfully pulled downward.

[Brief explanation of drawings]

Figure 1 shows the outline of the twin-belt continuous G+"l vI casting machine, and Figure 2 (a) and (b) are schematic views of the short side mold part of the twin-belt continuous casting machine as seen from the molten metal side. Figure 3 shows the temperature detection at 1℃ and ■ shown in Figure 2 when the belt material is cast separately in order to make the thermal conductivity of the long side mold material smaller than the thermal conductivity of the short side mold material. The graph shown in Fig. 4 shows the temperature distribution detected by the sensor, in which the belt material is cast as steel in order to make the thermal conductivity of the long-side mold material equal to the thermal conductivity of the short-side mold material according to the present invention. This is a graph showing the temperature distribution detected by the temperature detection sensor (■) shown in Figure 2.Top pad, 2...Belt (long side mold), 3...High melting point refractory, 4...Temperature Detection sensor, 5... Short side mold (side dam), 6, 7.8... Roll, 9...
Bracket, 10... Cylinder, 11... Cast side, 1
2...Short Figure 1 Figure 2 (A) Figure 3 C Time Figure 4 Time

Claims (1)

[Scope of Claims] 1. A pair of metal long-side molds that are arranged opposite to each other and move or rotate in synchronization with the slab to be formed, and a metal mold that is disposed between both ends of the pair of long-side molds. In the narrowing type long-side rotary continuous casting machine equipped with a short-side mold, the thermal conductivity of the main part of the long-side mold, at least in a portion adjacent to both side edges of the short-side mold, is calculated as the short-side mold. A continuous casting machine for thin plate cast slabs, characterized in that the machine exhibits a thermal conductivity equal to or higher than that of the main material constituting both side edges. 2. In the narrowing type long-side rotary moving continuous casting machine according to claim 1, the thermal conductivity of the long-side mold surface treatment material of at least the portion adjacent to the short-side mold of the long-side mold is determined by the short-side mold. A continuous casting machine for thin plate cast slabs, characterized in that the machine exhibits a thermal conductivity equal to or higher than that of the main material constituting both side edges. 3. In the continuous casting machine of the narrowing type long-side rotary moving type as set forth in claim 1, the thermal conductivity of the long-side mold gluing material at least in the portion adjacent to the short-side mold of the long-side mold is defined as the short side. A continuous casting machine for thin plate slabs, characterized in that the machine exhibits a thermal conductivity equal to or higher than that of the main material constituting both side edges of the mold. 4. In the narrowing type long-side rotary moving continuous casting machine according to claim 1, the thermal conductivity of the long-side mold composite material of at least a portion of the long-side mold adjacent to the short-side mold is determined as the thermal conductivity of the long-side mold composite material on both sides of the short-side mold. A continuous casting machine for thin plate slabs, characterized in that the machine exhibits a thermal conductivity equal to or higher than that of the main material forming the edge.