JPS611454A - Preventive method of metal penetration - Google Patents

Abstract

PURPOSE:To prevent the rippled surface owing to the penetration of a molten metal and to obtain a thin metallic sheet having an excellent surface characteristic by supporting a gate provided to the front end of the downstream of the molten metal poured onto the slope of a moving metallic sheet in such a manner as to repulse with the moving metallic sheet. CONSTITUTION:The gate constituted of gas members 1, 2 and a frame 3 is made turnable around a flucrum 5 and a spring 4 having such a spring constant at which the space between a belt 11 and the gate is maintained at <=0.1mm. is used. At least the corner parts of the members 1, 2 in contact with the surface of the belt 11 are contituted of an elastic member. The gate is therefore kept always in tight contact with the surface of the belt 11 without generating a clearance even if the belt oscillates sharply vertically.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Application in the pJi Industry) The present invention relates to a method for producing a thin metal plate having excellent properties in Table 1, for example, 2.about.20IIIV-, by continuous ribbing.

(Prior art) In order to produce garden trees, thin metal plates, such as thin steel plates, [L is bloomed and rolled to obtain a slab of 200-250 mm and 1 g;
Hot rolling this slab in pound strip mill or
ij2. 'v' is based on the l' process, in which molten steel is continuously cast to obtain a slab, and this is subjected to hot pressure i.

However, when there are 2 + tributary rains, 1,
There is a need for the development of a technology to directly obtain thin plates by continuous casting of molten steel, since the energy required to heat a large-scale hot strip mill or slab is safe.

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 several tens of meters or less 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.■ Slab slabs and mold inner wall surface Due to the friction between
It is difficult to raise it above ω/1 Ilin, and 2 m
/ If the value exceeds nin, the solidified shell will break and a flow of molten steel will gush out (
There was a problem that there was a risk of a breakout.

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 for the same, the present inventors first established
In No. 188882, a method and apparatus for manufacturing thin metal sheets by single-sided casting was proposed.

That is, it is a method of pouring molten steel onto a flat plate forming an inclined endless track and casting a thin steel plate, in which the forming direction and the direction of the poured molten steel flow are reversed, and *9 the flat plate forming an endless track is cast upward on the slope. A method in which molten steel is poured onto a flat plate while moving toward , and the lower end of the molten steel (molten metal) flow on the inclined moving flat plate is self-retained by the surface tension of the molten steel. A belt mechanism that is driven and has an endless track and an inclined plane, a means for supplying molten metal downward onto the inclined belt plane, a device for extracting slabs above the inclined plane, and a belt mechanism that drives the belt. This is a continuous casting device for molten metal, which consists of a device that drives the new surface upward.

This device is shown in FIG.

In FIG. 3, 11 is a casting belt or endless track, which is driven in the direction of arrow A. 12 is a belt drive wheel, 13 is a tundish, 14 is molten steel, and 15 is a solidified thin plate, that is, a slab.

When molten steel is continuously cast into a thin plate using this device, the molten steel 14 is supplied flowing down from the tundish 13 onto the surface of the belt 11, and flows down a certain distance on the surface of the belt 11 which is inclined by gravity. Go. Since the belt 11 is moving upward on the slope (in the direction of arrow A), in a steady state, the front end 17 and rear end 18 of the molten steel flow are at approximately constant relative positions from the point 19 where the molten steel flows from the tundish 13.

The solidified shell moves from the tip 17 of the molten steel flow on the belt 11 in the direction of arrow A.
It develops as it advances in the direction of , and eventually passes through the molten steel and becomes a completely solidified thin plate, which is wound up by a winding device.

With this technique, steel plates with a thickness of 2 to 20 mm can be manufactured by continuous casting. According to this technology, molten steel (
When the molten metal (molten metal) solidifies and the extraction speed of the solidified shell (slab) is synchronized with the moving speed of the track plane (belt), breakouts due to friction between the belt surface and the slab will not occur. Therefore, the casting speed can be dramatically increased.6 Also, since it is single-sided solidification, 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. Since there is no space constraint, there is no problem with the nozzle arrangement for supplying molten steel from the tundish.

However, even in the above-mentioned process for manufacturing thin metal sheets by casting, there are technical problems that need to be solved.

That is, the position of the molten steel flow tip 17 on the belt plane shown in FIG. 5 must be stable, and the molten steel flow tip must have a uniform planar shape in the belt width direction. Otherwise, a pattern due to hot water wrinkles will be formed on the lower surface of the thin sheet obtained by casting, which will seriously damage the surface quality of the thin sheet.

4 and 5 show the planar shape of the molten steel wave light if7 on the belt plane 6 The molten steel flow tip 17 on the belt plane has a tip shape as shown in FIG. 2, and its position in the belt movement direction is also stable. This is necessary for the quality of cast products.

From this point of view, even with the technique previously proposed by the present inventors in Japanese Patent Application No. 188862/1986, there still remained technical problems to be solved. The present inventors further changed the planar shape of the molten steel wave light j1i117 on the belt plane into a fourth shape.
Japanese Patent Application No. 58-80363 proposed a method for making the belt uniform in the width direction as shown in the figure and for stabilizing the position of the molten steel flow tip 17 in the belt movement direction.

That is, while stably maintaining the molten steel flow tip 17 on the belt plane at a desired position and desired planar shape on the belt plane by providing a weir on the belt plane,
This led to continuous casting.

The weir is formed by an adiabatic solid or a high temperature heated solid or sublimable U1 body, d21j gas jet. FIG. 2 shows one aspect of this.

In the actual mam shown in FIG. 2, a solid weir 214 is provided to hold the molten steel pool 7 above the solidified shell 6. It goes without saying that the solid spheres 21 have a required extent in the width direction of the belt 11.

The solid sphere 21 has a support rod 22 fitted in a tube 23 having an inner diameter larger than the outer diameter of the support rod 22, and is therefore freely displaceable in the vertical direction, and the movement of the belt 11 in the 1-downward direction is It is configured to follow.

Since the solid sphere 21 shown in FIG. 2 is constructed as described above, the bottom surface of the solid sphere 21 is in contact with the surface of the belt 11 with a force equal to the weight of the solid layer 21 itself and its support rod 22. There is.

For this reason, a gap is generated between the surface of the belt 11 and the bottom surface of the solid sphere 21, which allows the solid sphere 21 to follow sudden fluctuations in the vertical direction of the belt 11.

Also, as the solid sphere 21 moves, the belt 1
The solid ball 2 is pulled in the moving direction of the belt 11 due to friction between the surface of the solid ball 21 and the bottom surface of the solid ball 21, and there is a gap between the solid layer support rod 22 and the tube 23 in which it is fitted.
1 vibrated, and this also caused a number of gaps to be generated between the surface of the belt 11 and the bottom surface of the solid sphere 21.

In this way, molten steel is inserted into the FAFII generated between the surface of the belt 11 and the bottom surface of the solid sphere 21, and due to the insertion of the molten steel, a wrinkly pattern is formed on the side of the cast thin plate in contact with the belt 11. There was a problem in that the surface quality of the cast product (thin plate) was seriously damaged.

(Problems to be Solved by the Invention) This invention solves the above-mentioned flat plate (
This is caused by a gap that occurs between the belt and the bottom of a weir installed at the tip of the molten steel flowing down on the belt surface in a process in which molten steel is poured onto the belt and the slab is extracted upward from the inclined flat plate. The purpose of this invention is to provide a method that does not create a gap between the bottom of the weir and the belt surface in order to suppress the deterioration of the surface quality of the cast product (thin plate).

(Measures Pi to Solve the Problems) The gist of the present invention is to pour molten metal onto a metal plate that moves upward on an inclined surface, and cast the metal onto the inclined surface of the moving metal plate that forms the inclined surface. In a method for continuous casting of a thin plate in which a thin plate is extracted, a weir is provided at the leading end of the flow of molten metal poured onto the slope of the moving metal plate so that at least a part of the lower surface thereof is in contact with the surface of the moving metal, and A hot water boil prevention method characterized in that the layer is elastically supported on the movable metal plate and cast, and the elastic support of the weir to the movable metal plate is achieved by forming the lower part of the weir with a material rich in elasticity. The above-mentioned hot water boiling prevention method is performed by configuring the weir and pressing the lower surface of the weir against the surface of the moving metal plate with a spring, and the elastic support of the weir against the moving metal plate, the fulcrum of the weir support is set to a surface other than the surface of the weir. According to any of the above-mentioned methods of preventing hot water from forming, the weir is placed in a fixed position and is supported by a spring against a moving metal plate so as to rotate about the fulcrum.

The present invention will be explained in detail below.

In the weir structure at the tip of the molten steel flow on the belt surface, which the present inventors previously proposed in Japanese Patent Application No. 30363, when the belt 11 is suddenly displaced in a direction perpendicular to its surface, the weir is A gap is created between the belt surface and the stratified surface due to the inability to follow the displacement of the belt in the direction perpendicular to that surface at a speed that does not create a gap between the bottom surface and the belt surface. Ta.

Therefore, in the present invention, the weir is elastically supported and pressed against the belt surface. An example of an apparatus for implementing the present invention is shown in FIG.

In FIG. 1, 11 is a belt, 1.2 is a weir member, and 3 is 7 frames. A spring 4 presses and supports a part of the corner formed by the weir member 1.2 against the surface of the belt 11.

5 is a literal meaning, and P! by the weir member 1.2 and the frame 3! The weir is displaced as if rotating around this fulcrum 5.

6 is a shell of several yen, and 7 is a pool of melt.

When the grain is elastically supported by pressure against the surface of the belt 11, the displacement of the belt 11 in the direction perpendicular to the surface of the belt 11 is suppressed. It must be capable of displacing 7".111 By the way, if the relationship between the belt 11, weir, and spring is modeled and considered as shown in FIG. 6, the equation of motion is m'x++c(x+xz)+k( x+XI)=
Given by 0 - (1). Here, m is the mass % of the weir, xi is the displacement amount of the weir, x2 is the displacement amount of the belt, C is the damping coefficient, and k is the spring constant.

As1nω, t (A: amplitude, ω0
: Angular velocity, t: time) and solve equation (1) (and x
, -XI = exp(-ζωnt)X (c+5i
nqt+c2cosqt)...(2) ω. = 5, m = W 7g, m = tar+” L(2ζωD/ωn)/(1-ω.

'/ωn2)]).

Since the term ttS1 on the right side of equation (2) is O, in a steady state...(3) To prevent hot water from pouring in, the gap between the belt and weir (XI
A spring must be selected with a spring constant k such that XI) is 0.1 mm or less.

In one embodiment of the present invention, XI x2=O, LX
lo-'m, A = 2X 10-''m, ζ = 0.
01, m = 1.02kg52/m, ω.

= Casting was performed at 20.9 rad/s.

Substituting these values into equation (3), the spring constant becomes =
It becomes 9.4 kg/+am. Therefore, in order to perform continuous casting with a gap between the weir and the belt of 0.1 fflI11 or less, a spring 4 having a spring constant of 9.4 kg/mm or more is required.

On the other hand, the upper limit of the spring constant is limited by the belt driving force and the frictional force between the belt and the base surface. From this point of view, in this example, a spring having a spring constant IC of 15 kg/me was used.

By the way, in the weir structure at the tip of the molten steel flow on the belt surface that was previously proposed by the present inventors in Japanese Patent Application No. 58-30363, the solid weir Z1 connects the belt 11 surface and the solid weir 21 as the belt 11 moves. The solid layer support rod 22 is pulled in the moving direction of the belt 11 by the friction between the bottom surfaces.
Since there is a gap between the belt 11 and the tube 23 in which it is fitted, the solid body [21] vibrates, and this also creates a gap between the surface of the belt 11 and the bottom surface of the solid body 121.

Therefore, in the present invention, as described above, the weir member 1
．． 2 and the frame 3, the weir is configured to rotate around the husbandry 5. By configuring in this way, in this system, the mechanical wave is eliminated, and the stratification plane and belt 1 caused by the mechanical system are eliminated.
The occurrence of gaps between surfaces was better suppressed.

Further, in the present invention, at least the corner portion of the weir member 1.2 in contact with the surface of the belt 11 is made of an elastic member such as Cefmic 7 fiber, alumina fiber, glass fiber, or asbestos tube.

Since the present invention is constructed as described above, the weir is always in close contact with the belt surface even when the belt 11 undergoes sudden vertical vibrations, and no gaps are formed.

Although the above explanation has been made regarding continuous casting of Y# steel plate from molten steel, this invention is not limited to continuous casting of molten steel, but can also be applied to continuous casting of metals other than steel. Of course.

(Example) Molten steel was cast into a 10 mm thick copper strip using the apparatus shown in FIG. 1 having the spring 4 with a spring constant of 151 H/mm as described above.

A partial sketch of the belt contact surface side of the hook piece (copper band) at this time is shown in Figure 7.6 The surface of the cast piece had good surface properties with no creases! A pi band was obtained.

For comparison, FIG. 8 shows a partial sketch of the belt contact surface side of the tR band when molten steel is cast into a copper band using the conventional apparatus shown in FIG. 2. Wrinkles caused by the penetration of molten steel into the layered surface and belt surface have occurred over a wide area of the slab (copper strip).

(Effects of the Invention) Since the present invention is configured and operated as described above, when continuously casting a thin plate from molten metal, the casting process due to the insertion of molten metal between the solid ball and the belt can be avoided. To prevent deterioration of the surface quality of a thin plate and to enable production of a thin metal plate with excellent surface quality.

[Brief explanation of the drawing]

Figure #1 is an elevational view illustrating an example of a device for carrying out the method of the present invention, Figure 2 is an elevational view illustrating an example of holding the tip of molten steel using a conventional device, and Figure 3 is a continuous casting process. 4 and 5 are plan views showing the planar shape of the lower end of the injection flow in the process shown in Fig. 3. Fig. 6 is a spring system model showing the relationship between the belt, weir, and spring. FIG. 7 is a partial sketch showing the surface texture when molten steel is cast into a steel plate by the method according to the present invention, and FIG. 8 is a partial sketch showing the surface texture when molten steel is cast into a steel plate by the conventional technique. It is a sketch diagram. 1.2... Weir member, 3... Frame, 4... Spring, 5... Branch 6... Solidified shell, 7... 8 pools of molten steel, 1! ... Casting belt or endless track, 12
...Mold [driving wheel, 1t... tan tissue, 14...
・Unsolidified molten steel, 15... Solidified thin plate, 17.17'...
- Molten steel tip, 18... Molten steel rear end, 19... Gakucho falling point, 21... Solid ball, 22... Solid layer support rod, 23
···tube.

Claims (3)

[Claims] (1) In a method for continuous casting of a thin plate, in which molten metal is poured onto a metal plate that moves upward on a slope, and a cast thin plate is extracted in an upward direction of the slope of the moving metal plate forming the slope, the moving metal plate A weir is provided at the tip of the molten metal poured onto the slope so that at least a part of its lower surface is in contact with the surface of the moving metal, and the weir is elastically supported on the moving metal plate for casting. A hot water prevention method characterized by: (2) The elastic support of the weir to the moving metal plate is achieved by constructing the lower part of the weir with a highly elastic material and pressing the lower surface of the weir against the surface of the moving metal plate using a spring. Method for preventing hot water boiling described in section. (3) Elastic support for the moving metal plate of the weir is achieved by placing the fulcrum of the weir support at a position other than the surface of the weir, and pressing and supporting the weir against the moving metal plate using a spring so as to rotate around the fulcrum. A method for preventing boiling water according to claim 1 or 2.