JPS6297751A - Continuous casting device for thin sheet - Google Patents

Abstract

PURPOSE:To continuously cast a thin sheet having an excellent surface characteristic and uniform thickness without generating breakout and rupture by determining the angle of inclination of an endless metallic belt which is inclined to rise in a casting direction with respect to the horizontal plate of the belt by a mathematical expression. CONSTITUTION:A molten steel is poured from a pouring device 6 into the space formed on the surface of the inclined metallic belt 1 by a stationary gate 5 and movable side gates 4 to form a molten metal pool 8. the rear surface of the belt 1 is cooled with water by a cooler 3 and a solidified layer develops in the molten metal pool 8. the solidified layer is ejected as the thin sheet to the upper part of the slope of the belt 1. The pouring flow 7 of the molten steel is positioned apart at least 100mm from the rear stationary gate 5 and the angle theta of inclination of the belt 1 with the horizontal plane is determined within the range of the mathematical expression. In the equation, (b) is the width of the ingot l is the length of the free surface of the molten steel pool of the metallic belt.

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 OF THE INVENTION 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 250 mm, and this slab is hot rolled in a hot strip mill, or molten steel is rolled. The process involves continuous casting to obtain a slab, which is then hot rolled.

However, since these conventional techniques require energy to heat a large-scale hot strip mill or slab, efforts have been made to develop techniques for directly obtaining thin plates by continuous casting of molten steel.

Conventionally, when continuously casting molten steel, a method has generally been used in which the molten steel is injected into a mold, solidified around the cross section, and then pulled out downward. However, with this method, it is difficult to obtain slabs with a thickness of less than 10,111 mm due to the relationship between the diameter of the nozzle that injects molten steel into the mold and the cross-sectional dimensions of the mold. ■ Between the slab and the inner wall of the mold Due to the friction of
It is difficult to raise it above m/a+in, and 2m/f
If it exceeds f1 inch, there is a risk that the solidified shell will break and a molten steel flow will blow out (breakout).

There was such a problem.

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 applicant previously filed a Japanese Patent Application No. 58-188.
In No. 882, a method and apparatus for manufacturing thin metal sheets by single-sided casting was proposed.

That is, this method and apparatus is a method of pouring molten steel onto a flat plate forming an inclined endless track to cast a thin steel plate, and in which the casting direction and the method of pouring molten steel flow are reversed, that is, the flat plate forming an endless track is cast on an inclined plane. The molten steel is poured onto a flat plate while moving upward, and the lower end of the molten steel (molten metal) flow on the inclined moving flat plate is self-held by the surface tension of the molten steel. a belt mechanism that is driven by wheels and forms an endless track and has an inclined surface;
A continuous flow of molten metal consisting of a means for supplying molten metal down onto an inclined peltomo surface, a device for extracting slabs above the slope, and a device for driving a belt upward on the slope via a drive wheel. It is a casting device.

With this technology, steel plates with a thickness of 2 to 20+ am, for example, can be produced by continuous casting. According to this technology, molten steel (molten metal) is solidified on a track plane that is inclined and moves upward, and the extraction speed of the solidified shell (9 pieces) is synchronized with the moving speed of the track plane (belt). If this is done, 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 during PI production is in contact with the belt surface, but the top surface is in contact with the molten steel or the atmosphere, and since there is no space constraint such as a mold, there is no need to There are no problems with the nozzle arrangement for supplying molten steel.

The present applicant has further improved this technique 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. The patent application No. 59-12 describes a process for forming a molten metal pool in the metal belt to solve the problem of wrinkle formation in the slab caused by the uneven planar shape of the tip of the molten metal injection flow on the metal belt.
It was proposed in No. 0588.

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

That is, in order to smoothly develop a solidified shell generated from the deepest part of the molten metal pool and to obtain a thin metal plate with excellent surface quality and a uniform desired thickness by continuous casting, the molten metal as shown in FIG. It must be ensured that there is no solidification shell attack (21) due to the injection flow (7).

In addition, in the continuous casting process using the single-sided solidification method mentioned above, in the molten metal pool area.

The molten metal in contact with the side art platform forms the "ear" part (1) shown in Figure 3.
5) may form gutter-like slabs.

Since parts other than the flat parts of the slab must be cut and removed, the yield of good slabs in the casting process is reduced.

From this point of view, in a single-sided solidification continuous casting device that uses an endless metal belt as a component, the depth of the molten metal pool formed on the metal belt, that is, the inclination angle of the endless metal belt, is an important requirement. .

Problems to be Solved by the Invention This invention has been described above. Gold FA with excellent surface quality and uniform thickness that solves the problems in conventional technology
The purpose of this invention is to provide a continuous casting device using a single-sided solidification method that can continuously cast thin plates at a high yield.

Means for Solving the Problems The gist of the present invention is to provide an endless metal belt that is inclined so that the casting direction is upward and a cooling device is attached to the back side, and a pool of molten metal that is placed on the metal belt. a rear fixed weir for forming the metal belt, and a side stage that moves in synchronization with the metal belt, the injection position of molten metal is positioned a predetermined distance from the rear fixed weir, and the horizontal surface of the metal belt The angle of inclination is 0 [degrees].

-1 o minus π (where b is the width of the slab (thin plate), inclusive is the free surface length of the molten metal puddle formed on the metal belt in the lengthwise direction of the metal belt, and b is the width of the slab) There is a thin plate continuous casting apparatus characterized by:

The present invention will be explained in detail below.

FIG. 1 shows an outline of the continuous thin plate casting apparatus according to the present invention.

In Figure 1, (1) is a metal belt and a pulley (
2) and forms an endless track.

(3) is a cooling device that cools the metal belt (1) from the back side during the casting process. (4) is side 1w! - It is composed of a chain of heat-resistant blocks wound around a sprocket wheel (not shown) to form an endless track, and moves in synchronization with a metal belt (1).

(5) is a rear fixed weir, which is provided so as to extend in the width direction of the metal belt, and at least a part of its 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. be done.

(6) is an injection device, from the rear fixed weir (5),
The injection stream (7) is arranged at a predetermined distance in the casting direction. (8) is a water reservoir, and an injection device (6) is installed in a space surrounded by a fixed rear weir (5) and a movable platform (4) on the side of the metal belt (1).
formed by molten metal supplied from

(9) is a solidified thin plate, that is, a slab, and a metal belt (
The hot water is extracted from the pool (8) above the slope formed by 1), rolled or surface-shaped by the rolling rolls (!0), wound up by the winding device (11), and made into a thin plate (strip) coil ( 12).

FIG. 2 shows the geometrical relationship of the device shown in FIG.

In the present invention, the endless fully bent belt (1) shown in FIG.
The angle 0 [degrees] formed by the surface of the water surface is determined as shown in equation (1).

The reason for this will be explained below.

First, 0.8<0 ・ meeting −(
2) is because if the depth of the molten metal (molten In) pool (8) is made smaller (shallower) than this, the molten metal injection flow (7) shown in Figure 1 will directly flow into the solidified shell. When the upper surface is remelted, the upper surface of the solidified shell becomes extremely uneven, making it impossible to obtain a cast thin plate with excellent surface properties and uniform thickness.

Next, to explain the reason for setting 10Q, π, the molten metal pool (
The depth h in 8) is h=Q, sin Om m m (4), where the inclusion represents the free surface length of the metal molten pool formed in the metal belt) in the length direction of the metal belt. Further, 0 represents the angle formed between the casting belt and the horizontal plane.

However, in order to suppress the yield loss due to cutting and removing the ear J (15) as shown in Fig. 3, it is necessary to
For one side, the relationship in equation (5) must be satisfied, that is, for one side it is 10% or less, so h≦b/
It becomes 10. However, b represents the width of the slab (strip).

Equation (5) is derived from equation (4).

5inOku□・IIφ (5) 10Q.

When θ is small, it is 51nO*θ [radians], so this is substituted into equation (5) and converted to frequency to obtain equation (3).

Therefore, in order to better solve the technical problems of the present invention, the angle θ between the endless metal belt (1) and the horizontal plane should be adjusted.
[degrees] must be 10i π.

Functions The functions of the thin plate continuous casting apparatus of the present invention will be explained below.

The metal belt (1) is moved by a pulley (2), e.g. It is driven at a speed of Om/win. At the same time, the side weir (4) is also driven by a sprocket wheel (not shown) in synchronization with the metal belt (1).

Molten metal, such as molten steel, is injected from an injection device (8) into the space formed on the inclined surface of the metal belt (1) by the fixed rear weir (5) and the movable side layer (4),
A hot water pool (8) is formed.

The metal belt (+) is water-cooled on the back side by a cooling device (3) during the casting process starting from the rear fixed weir (5).

At the bottom of the pool (8), solidification begins on the surface of the metal bell (1) that passed through the lower surface of the rear fixed weir (5), and a solidified layer develops in the pool, forming a thin plate ( pI piece) is extracted above the slope by the metal belt (1).

In this invention, in order to achieve high productivity by continuous casting of a thin plate with excellent surface properties (no wrinkles, double skin, etc.) and a uniform thickness, the position of the injection flow (7) is required. is important.

That is, as shown in FIG. 1, on the surface of the metal belt (1),
Solidification begins immediately after the rear fixed weir (5). Due to the presence of this rear fixed weir (5), the solidification start point on the surface of the metal belt (1) becomes uniform, which is caused by the non-uniformity of the solidification start point. The formation of hot water wrinkles, double skin, non-uniform coagulation layer thickness, etc. are 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 thickness is thin, the solidified shell once solidified will be remelted. This makes it difficult to extract thin plates (slabs) with excellent surface quality and uniform thickness.

In addition, after the solidified layer (Pj piece) is extracted from the /gj pool (8), or when the injection flow (7) is positioned at the end of the slab extraction side of the molten metal pool (8), , injection flow (
The heat and falling energy of 7) cover the solidified layer that has developed up to that point, impairing the surface quality of the tzl 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).
9 of the length of the metal belt in the moving direction of the hot water pool (8)
For the reasons mentioned above, it is important to keep the value within 0%.
is necessary.

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

It is a thin plate (strip) coil (12).

Effects of the Invention This invention can produce thin metal sheets with excellent surface properties and uniform thickness with high productivity without worrying about breakouts or ruptures; This greatly simplifies the process, resulting in significant energy savings and cost savings.

[Brief explanation of drawings]

FIG. 1 is an elevational view illustrating the thin plate continuous casting apparatus of the present invention;
Figure 2 is an elevational view showing the geometrical relationship of the apparatus shown in Figure 1, Figure 3 is an elevational view illustrating the "ears" that occur in the continuous casting process by single-sided solidification, and Figure 4 is an elevational view showing the geometric relationship of the apparatus shown in Figure 1. FIG. 2 is an elevational view illustrating a pattern of remelting of a solidified shell by a molten metal injection flow in a continuous casting process with one-sided solidification. l... Metal belt, 2... Pulley, 311... Cooling device, 4... (movable type) side weir, 5... (fixed type) rear layer, 6... Injection device, 7... ...Injection flow, 8.
・φ trough, 9... solidified thin plate, 10... rolling roll, 11φ... winding device. 12...Thin plate coil, 15...Ear portion, 21...Coagulation shell attack.

Claims (1)

[Scope of Claims] An endless metal belt that is inclined so that the casting direction is upward and that has a cooling device attached to the back side; a rear fixed weir for forming a pool of molten metal on the metal belt; It has a side weir that moves in synchronization with the metal belt, and positions the molten metal injection position a predetermined distance away from the rear fixed weir, and sets the metal belt at an inclination angle of 0 degrees with respect to the horizontal plane. 8≦0≦(b/10l)・(180/π) (where, b is the slab (thin plate) width, l is the free surface length of the molten metal pool formed on the metal belt in the lengthwise direction of the metal belt, (b represents the width of the slab.) A continuous thin plate casting apparatus.