JPH0555219B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a single-sided solidification continuous casting apparatus for producing sheet metal, such as steel strip.

BACKGROUND TECHNOLOGY Conventionally, in order to produce a thin metal plate, such as a thin steel plate, a steel ingot is bloomed to obtain a slab with a thickness of 200 to 2500 mm, and this slab is hot rolled in a hot strip mill, or The process involves continuous casting of molten steel to obtain a slab, which is then hot rolled.

However, when using these conventional techniques,
It is desired to develop a technique for directly obtaining thin plates by continuous casting of molten steel in large-scale hot strip mills and places that require energy to heat slabs.

Conventionally, when continuously casting molten steel, a method has generally been used in which the molten steel is poured into a mold, the periphery of the molten steel within the cross section of the mold is solidified, and then the molten steel is pulled downward. However, with this method, it is difficult to obtain slabs with a thickness of several tens of millimeters or less due to the relationship between the diameter of the nozzle through which molten steel is injected into the mold and the cross-sectional dimensions of the mold. Friction between the slab and the inner wall of the mold Therefore, it is difficult to increase the slab drawing speed to 2 m/min or more, and there is a risk that if it is increased to 2 m/min or more, there is a risk that the solidified shell will break and a flow of molten steel will blow out (breakout). Ta.

In order to solve these problems in the conventional continuous casting process and provide an efficient manufacturing method by continuous casting of thin plates and an apparatus therefor, the present inventors previously proposed a single-sided solidification method in Japanese Patent Application Laid-Open No. 58-90357. A method and apparatus for manufacturing thin metal sheets were proposed.

That is, it is a method of pouring molten steel onto a flat plate forming an inclined endless track and casting a thin plate, in which the casting direction and the direction of the flow of poured molten steel are reversed, that is, the flat plate forming an endless track moves upward on the slope. Continuous casting method in which molten steel is poured into a flat plate under conditions such that the lower end of the molten steel (molten metal) flow on an inclined moving flat plate is self-retained by the surface tension of the molten steel, and an infinite casting method driven by driving theory. A belt mechanism having a trajectory and an inclined plane, a means for supplying molten metal downward onto the inclined belt plane, a device for extracting slabs on the upper side of the inclined plane, and a belt mechanism that moves the belt onto the inclined plane through a driving mechanism. This is a continuous casting device for molten metal, which consists of a device that is driven in different directions.

With this technique, steel plates with a thickness of 2 to 20 mm, for example, can be manufactured by continuous casting. According to this technology, molten steel (molten steel metal) solidifies on a track plane that is inclined and moves upward, and the extraction speed of the solidified shell (slab) and the moving speed of the track plane (belt) are synchronized. If so, breakout due to friction between the belt surface and the slab will not occur, so the casting speed can be dramatically increased.

In addition, since solidification is performed on one side, the bottom surface of the slab is in contact with the belt surface during casting, but the top surface is in contact with the molten steel or the atmosphere, and there is no space constraint such as a mold, so there is no need for a tundish. There are no problems with the nozzle arrangement for supplying molten steel.

The present inventors further improved this technique, and provided a fixed weir extending in the width direction of the metal belt at the lower end of the molten metal injection flow so as to be in elastic contact with the metal belt. Japanese Unexamined Patent Application Publication No. 1454/1983 discloses a process for forming a molten metal pool on the top of the metal belt to solve the problem of the formation of molten metal wrinkles on the painted pieces due to the uneven planar shape of the tip of the molten metal injection flow on the metal belt. It was proposed in

However, even with these techniques, there were still technical problems to be solved.

That is, by disposing a fixed weir extending in the width direction of the metal belt at the lower end of the molten metal injection flow so as to be in elastic contact with the metal belt, a molten metal pool is formed on the metal belt. By doing so, the problem of deterioration of the surface quality of the slab due to the irregularity of the planar shape of the tip of the molten metal injection flow on the metal belt was solved, but on the surface in contact with the molten metal pool of the fixed weir, Solidification of the molten metal may occur, which may result in cracks called cold shots.

Problems to be Solved by the Invention This invention solves the problem of cold shunt occurring in the process of pouring molten metal onto the belt forming the inclined endless track described above and extracting slabs in an upward direction on the slope. It was made with the aim of solving the problem.

Means for Solving the Problems The gist of the present invention is that the casting direction is diagonally upward, a slope is formed that moves in that direction, and a cooling means is attached to the back of an endless metal belt. , the endless metal belt extends in the width direction, and all or part of the lower surface is elastically pressed against the upper surface of the endless metal belt, so that a puddle of molten metal supplied from the outside is placed on the endless metal belt. The continuous thin plate casting apparatus is provided with a fixed rear weir for forming thin plates, characterized in that the continuous thin plate casting apparatus is provided with means for heating the fixed rear weir.

This invention will be explained in detail below.

In the process of researching a thin plate casting process using single-sided solidification on an inclined metal belt, the present inventors discovered that the temperature of a fixed weir in contact with a pool formed on the metal belt was maintained at 1300 to 1700°C. It has been found that the problem of cold shunt due to solidification of molten metal on the sides of a fixed weir can be better solved by.

FIG. 1 shows an embodiment of the fixed weir of the continuous thin plate casting apparatus of the present invention, and FIG. 2 shows the overall profile of the embodiment of the apparatus.

In FIG. 2, reference numeral 1 denotes a metal belt that is wound around a pulley 2 to form an endless track. 3 is a cooling device which cools the metal belt 1 during the casting process.
is cooled from its back side. Reference numeral 4 denotes a side weir, which is constituted by a heat-resistant block chain wound around a sprocket wheel (not shown) to form an endless track, and is driven in synchronization with the metal belt 1.

Reference numeral 5 denotes a fixed rear weir whose lower surface is in contact with the upper surface of the metal belt and is elastically pressed against the upper surface of the metal belt by, for example, a spring. Reference numeral 6 denotes an injection device, which is disposed at a predetermined distance from the rear fixed weir 5 in the casting direction so that the injection stream 7 is positioned therein. Reference numeral 8 denotes a pool, which is formed by molten metal supplied from the injection device 6 into a space surrounded by the rear fixed weir 5 and the movable side weir 4 on the surface of the metal belt 1.

9 is a solidified thin plate, that is, a slab, which is extracted from the pool 8 above the slope formed by the metal belt 1, rolled or surface-shaped by a rolling roll 10, and sent to a winding device 11. It is then wound up into a thin plate (strip) coil 12.

In FIG. 1, 5 indicates the entire fixed weir.

13 is a frame, and 14 is a pressure spring, which functions to elastically press the lower end surface of the fixed weir 5 against the upper surface of the endless metal belt 1.

15 is a fulcrum, around which the fixed weir 5 is rotatably supported, and is rotated clockwise in FIG. 1 by a spring 14 and pressed against the upper surface of the endless metal belt 1.

Reference numeral 16 denotes an electrical heating heating element, which is made of, for example, alumina graphite, silicon carbide, etc., and is controlled by controlling the temperature of the fixed weir 5 by supplying electric power through a conductive wire 17 and a temperature control device (not shown). Maintain the temperature within the range of 1300-1700℃.

In this embodiment, from the viewpoint of ease of temperature control, electric power was used as the heat source for raising the temperature of the fixed weir 5, but other heat sources may be used.

For example, a gas combustion flame may be applied to the back surface of the fixed weir 5 to raise the temperature.

Function The function of the thin plate casting apparatus of the present invention described above will be described.

The metal belt 1 is moved by a pulley 2, for example.
It is driven at a speed of 70m/min. At the same time, the side weir 4 is also driven in synchronization with the metal belt 1 by a sprocket wheel (not shown).

Prior to the start of continuous casting, the rear fixed weir 5
It is heated to, for example, 1550° C. by electrical heating.

After the temperature of the fixed rear weir 5 is completed, the injection device 6 is inserted into the space formed on the inclined surface of the metal belt 1 by the fixed rear weir 5 and the movable side weir 4.
Molten metal, for example molten steel, is injected from the molten metal to form a sump 8.

The back surface of the metal belt 1 is water-cooled by a cooling device 3 during the casting process starting from the rear fixed weir 5 .

Then, solidification begins on the surface of the metal belt 1 that has passed the lower surface of the rear fixed weir 5 at the bottom of the pool 8.
A solidified layer develops below the surface of the molten metal, and is extracted upward on the slope by the metal belt 1 as a thin plate (slab).

In the present invention, the position of the injection stream 7 is adjusted in order to obtain a thin plate having an excellent surface quality without wrinkles or double skin and a uniform thickness by continuous casting with high productivity. is important.

That is, as shown in FIG. 2, solidification begins on the surface of the metal belt 1 immediately after the rear fixed weir 5. Due to the existence of this rear fixed weir 5, the solidification starting point on the metal belt surface becomes uniform, and the formation of hot water wrinkles and double skin due to non-uniform solidification starting point,
Non-uniformity in the thickness of the coagulated layer, etc. is prevented.

If the injection flow 7 is located at or near the rear fixed weir 5, the solidification start point will be disturbed, and since the solidified shell is thin, the solidified shell will be remelted, causing the surface texture to change. This makes it difficult to extract thin sheets (slabs) of good, uniform thickness.

In addition, after the solidified layer (slab) has been extracted from the molten metal pool 8, or if the injection stream 7 is located at the end of the molten metal pool 8 on the slab extraction side, the heat of the injection stream 7 is The falling energy rips away the solidified layer that had developed up to that point, damaging the surface quality of the thin plate (slab) and making the thickness uneven.

According to research by the present inventors, the injection flow 7 is at least 100 mm from the slab extraction side surface of the rear fixed weir 5.
away, and the length of the metal belt in the moving direction of the pool 8.
It is necessary to position it within 90% for the reasons stated above.

Now, the thin plate (slab) 9 extracted from the hot water pool 8
is further rolled or shaped by a pair of rolling rolls 10 and wound up by a winding device 11 to form a thin plate (strip) coil 12.

Effects of the Invention The present invention enables production of thin metal sheets with excellent surface quality and uniform thickness with high productivity without any fear of breakouts or fractures. This greatly simplifies the process, resulting in significant energy savings and cost savings.

[Brief explanation of the drawing]

FIG. 1 is an elevational view showing an embodiment of a fixed weir of a continuous casting apparatus of the present invention, and FIG. 2 is an elevational view showing the overall profile of the continuous casting apparatus of the invention. 1... Metal belt, 2... Pulley, 3... Cooling device, 4... Side weir, 5... Fixed weir, 6... Injection device, 7... Injection flow, 8... Water pool, 9... Solidified thin plate, 10... Rolling roll, 11... Winding device, 12... Thin plate coil, 13... Frame, 1
4... Pressing spring, 15... Fulcrum, 16... Electric heating heating element, 17... Conductive wire.

Claims (1)

[Claims] 1. On an endless metal belt with the casting direction diagonally upward, forming a slope that moves in that direction, and having a cooling means attached to the back side, the casting direction extends in the width direction of the endless metal belt, and the entire lower surface is Alternatively, a thin plate continuous casting device is provided with a rear fixed weir, a part of which is elastically pressed against the upper surface of the endless metal belt to form a puddle of molten metal supplied from the outside on the endless metal belt. A thin plate continuous casting apparatus characterized in that a means for heating a rear fixed weir is provided.