JPH0332448A - Method and device for adjusting breaking position at the time of twin directional drawing type horizontal continuous casting - Google Patents

Abstract

PURPOSE:To adjust frictional resistance between a cast slab strand and an inner wall face of a horizontal mold and to correct shifting of breaking position by pushing the cast slab strand toward the width direction or the thickness direction in the end part of horizontal mold. CONSTITUTION:At first, the horizontal mold 10 is oscillated in sine wave in the horizontal direction at the prescribed stroke with the oscillation device. Molten steel from a tundish is poured from center part of this horizontal mold 10 and this poured molten steel is broken in the horizontal mold 10 and divided into right and left sides and cooled and solidified while shifting toward both end parts of the horizontal mold 10. In this result, the formed cast slab strands 11 are drawn out from both end parts of the horizontal mold 10. Successively, in both end parts of this horizontal mold 11, the frictional resistance device composed of two sets of roll groups is arranged to push each cast slab strand 11 toward the width direction and the thickness direction with this frictional resistance device. In this result, the frictional resistance between the cast slab strand 11 and the inner wall face of the horizontal mold 10 is adjusted to adjust the breaking position of molten steel.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method and device for adjusting the fracture position during bidirectional drawing type horizontal continuous casting. The present invention relates to a method and an adjustment device for adjusting the position of the fracture surface of distributed and supplied molten steel with respect to the inner wall surface of the horizontal mold, that is, when the fracture position deviates from a plane perpendicular to the direction in which the slab strand is pulled out.

Conventional technology In modern steelmaking operations, the continuous casting method dominates.
The continuous casting method has also shifted from a vertical type to a curved type, and recently, a horizontal type, that is, a horizontal continuous casting method has been proposed and transitioned.

To explain in more detail, in the vertical type of continuous casting method, in order to increase the static pressure of molten steel and improve the quality of the slab,
Because the height of the equipment needs to be about 30-401cm,
Buildings and other structures will be made taller and larger accordingly. As a result, these construction costs are extremely high;
Equipment becomes larger.

Also, with the curved type, the height of the building and equipment can be lowered to some extent than with the vertical type, but the height of the building and equipment can be lowered to some extent than with the vertical type. Since the cast slab strand is curved, it is necessary to separately provide a straightening device for straightening the curved portion of the slab, which complicates the equipment itself and its operation.

On the other hand, in the horizontal type, a supply container such as a tundish is connected to one end of the horizontal mold that is placed horizontally and is vibrated horizontally. During the transition to the other end, the molten steel is cooled and solidified, and the slab strand is continuously pulled out from the other end of the horizontal mold. With this horizontal type,
The height of the building and equipment is significantly lower, allowing the equipment to be significantly more compact and equipment costs to be extremely low.

However, since the slab strand can only be pulled out from the other end of the horizontal mold, that is, from only one direction, there is a problem in terms of production.

From this point, as shown in JP-A No. 58-138544, molten steel is supplied from the tundish to approximately the center of the horizontal mold, and this TJtJ4 is broken at the center and distributed to the left and right toward both ends. A bidirectional drawing die has been proposed in which the cast slab strand is cooled and solidified during the process, and the cast slab strand is simultaneously pulled out from both ends.

That is, in the bidirectional drawing die, as shown in Fig. 5, a tandem plate 2 is connected through a feed nozzle to approximately the center of a horizontal mold 1 that vibrates horizontally with a predetermined amplitude, and the molten steel 3 from the drawn steel is After being supplied to the dumpster 2, it is continuously injected into the center of the horizontal mold 1. In the center of the horizontal mold 1, the molten steel 3 collides with the bottom of the inner wall surface and breaks, and as a result, the molten steel 3 distributed to the left and right passes through the cold inside the horizontal mold 1 while moving to both ends of the horizontal mold 1. The cast slab strand 4 is cooled and solidified by the W water 1a, and continuously pulled out by upper and lower drawing pinch rolls 6 from both ends of the mold via dummy roses that are engaged with each tip of the slab strand 4. but,
When the slab strand is pulled out from both ends of the horizontal mold in this manner, it is necessary that the injected molten steel be broken approximately at the center of the mold. However, this fracture surface is
Initially, it is located approximately in the center of the mold, but during vI construction it moves and the fracture surface is displaced to either end of the horizontal mold. When the fracture surface moves and becomes displaced in this way, and its position becomes unstable, the molten steel supplied to the surface of the slab that has been solidified may be solidified, resulting in surface defects such as daspuru skin.

From this point of view, various fracture surface control mt methods have been proposed, one of which is a method of adjusting the drawing speed of the left and right slab strands. For example, as shown in FIG. 6, when the fracture surface indicated by the symbol A in the horizontal mold 1 is displaced toward the right side toward the plane of the paper, the drawing speed of the left slab strand 4a is increased (V+= Vo ten Δ
V), the drawing speed of the right slab strand 4b is reduced (V2-Vo-ΔV), and one cross section A is returned to the center of the horizontal mold 1.

However, the fracture surface 8 may not only be simply deviated in the direction of drawing the slab strand, but also be deviated from its vertical plane. In this case, as shown in FIG. 2, for example, the fracture positions (hereinafter simply referred to as fracture positions) B+ and B3 of the fracture surface with respect to the opposing inner wall surfaces 1a and lc of the horizontal mold 1 are displaced in opposite directions or If such a deviation occurs, it cannot be adjusted simply by adjusting the drawing speed of the slab strand, as described above.

In short, the positions of the fractured surfaces behave independently of each other, and when they behave independently, correction cannot be made by the conventional adjustment method using the drawing speed.

Problems to be Solved by the Invention The present invention aims to solve the above-mentioned drawbacks. Specifically, in a horizontal mold that vibrates with a predetermined stroke, even if the position of the fracture surface with respect to each surface of the horizontal mold behaves independently, We propose a control method and apparatus that can adjust the position of each surface of this fracture surface, obtain slabs with good surface properties, and perform high-speed casting of layers.

Means for Solving the Problems and Their Effects In other words, the method of the present invention involves injecting molten steel into a horizontal mold that vibrates horizontally with a predetermined stroke, and breaking the molten steel at a fracture surface approximately in the center of the horizontal mold. The distributed molten steel is distributed to the left and right, and while it is transferred to both ends of the horizontal mold, it solidifies horizontally to form slab strands, and these left and right slab strands are pulled out from both ends of the horizontal mold N times. When the fracture position of this fracture surface with respect to the inner wall surface of the horizontal mold deviates from a plane perpendicular to the drawing direction of the slab strand, the slab strand is pressed in the width direction or thickness direction at the end of the horizontal mold. This method is characterized by adjusting the rIJ friction resistance between the slab strand and the inner wall surface of the horizontal mold, and correcting the deviation of the fracture position.

In addition, in carrying out the method of the present invention, the molten steel is distributed to the left and right at approximately the center of the horizontal mold, which is vibrated horizontally with a predetermined stroke and into which 1 ml is injected from approximately the center.
In a bi-directional drawing type horizontal continuous casting machine, each molten steel is cooled and solidified to form a slab strand while being transferred toward both ends of a horizontal mold, and each slab strand is continuously pulled out. In addition to the pinch rolls used to continuously pull out the strands, the strands are pressed against each end of the horizontal mold from the width direction or the thickness direction to create a gap between each strand and the inner wall surface of the horizontal mold. It is preferable to have a *1m resistance adjustment 8i position for adjusting the frictional resistance.

Therefore, the structure of these means and their operation will be explained in more detail as follows.

Note that FIG. 1 is a perspective view showing a part of an example of an adjusting device for carrying out the method of the present invention, and FIGS. 2 and 3 are explanatory diagrams of modes of adjusting the fracture position according to the present invention.

In FIG. 1, the symbol @10 indicates a horizontal mold, and this horizontal mold 10, like the conventional horizontal mold 1 shown in FIG. Depending on the position, it vibrates sinusoidally in the horizontal direction with a predetermined stroke. Molten steel from Dandaitsu is injected from approximately the center of this horizontal mold 10, this injected molten steel is broken within the horizontal mold 10, distributed to the left and right, and cooled while the molten steel moves toward both ends of the horizontal mold 10. Solidified and thus formed slab strand 11
are pulled out from both ends of the horizontal mold 10.

Next, at both ends of the horizontal mold 10, the rIJ friction resistance device consisting of two sets of rolls presses each slab strand 11 in the width direction and thickness direction. By this, the *m resistance between the slab strand and the horizontal mold inner wall surface is adjusted, and the fracture position of the molten steel is adjusted.

That is, as shown in FIG.
2b, 12c, and 12d are each configured to be movable by a movable cylinder (the movable cylinders 13b and 13d shown in FIG. 1 move the rolls 12b and 12d, respectively; (omitted from illustration). In the case where the fracture positions B2 and B4 with respect to the inner wall surfaces 1a, lb, lc, and 1d of the horizontal mold 1, e.g., the inner wall surfaces 1b and ld of the molten steel, are shifted in opposite directions (see Fig. 2), Rolls 12b and 12d corresponding to those inner wall surfaces 1b and ld
The hydraulic or pneumatic moving cylinders 13b, 13d
It is activated by For example, at both ends of the horizontal mold 1, as shown in FIG. 2, the fracture position B2 on the inner wall surface 1b side is toward the right side of the slab strand 11, and the fracture position B4 on the inner wall surface 1d side is on the left slab strand. If it deviates to the 11L side, the fracture position B of the inner wall surface 1b? Slab strand 11L
To the side, the fracture position B4 of the inner wall surface 1d is connected to the slab strand 11.
Roll 12b on the side of slab strand 111II in order to deviate to the side of overlap.

12d to the inner wall surface 1b side, and the rolls 12b and 12d on the slab strand 11L side to the inner wall surface 1d side. When operated in this manner, the frictional resistance between the shell of the slab strand 111II and the inner wall surface 1b and the frictional resistance between the slab strand 11
The FJyA resistance between the L-side shell and the inner wall surface 1d increases, making it difficult for the drawing speed to propagate to the center of the slab strands 11L and 11^. In other words, as a result of the shell deforming elastically or plastically, the fracture position B2 moves toward the slab strand 11L side, and the fracture position 1184
moves to the 11-thick side of the slab strand and stabilizes the fracture position.

To explain in more detail, in a horizontal mold, if the fracture positions or break points of the opposing inner wall surfaces shift, the contact pressure or *II resistance between the mold and the shell of the slab strand on the side where the break points should be brought closer increases. , pressed by a roll. As a result, on each inner wall surface of the horizontal mold, if a zone with high contact pressure occurs on one side of the opposing surface, a zone with low contact pressure will be formed on the other side, and due to this change in contact pressure. The difference in frictional force causes a difference in the formation of solidified shells as follows, and the fracture positions or break points become closer to each other. In other words, in the zone where the contact pressure is high, the frictional force between the mold inner wall surface and the solidified shell is large, and in this region F
Compression restraint acts on the solidified shell due to the aIII resistance, and this V5 effect makes it difficult for the solidified shell to extend toward one of the slab strands, so it is placed on the other slab strand side. On the other hand, on the opposing inner wall surface, the *friction resistance is small, so the compressive load is lower than the previous *i low resistance lil region, and the new solidified shell generated at the fracture position or break point 1~ Since the frictional resistance is small in the state where it is in contact with the previously generated solidified shell, it remains as it is, moves away from the other slab strand, and shifts toward one slab strand.

Example: Pour the fJ steel from the tundish into a horizontal mold,
The cast slab strand was continuously pulled out from both ends of the cast piece to perform continuous casting.

In this casting, as shown in Fig. 1, the casting speed and breakpoint were stabilized in the case where the fracture position or breakpoint was adjusted by the roll according to the method of the present invention, and in the case where the drawing speed was simply adjusted as in the conventional method. The relationship between the properties and the properties of the slab was determined, and the results were as shown in FIG. 4. According to the method of the present invention, the break point stability was improved and the occurrence of flaws on the surface texture of the slab was reduced.

In FIG. 4, the * mark indicates the method of the present invention, and the circle mark indicates the conventional method.

<Effects of the Invention> As explained in detail above, the present invention injects molten steel into a horizontal mold that vibrates horizontally with a predetermined stroke.
The M is broken at the fracture surface of the horizontal mold approximately in the center and distributed to the left and right, and while the distributed molten steel is transferred toward both ends of the mold, it solidifies horizontally to form slab strands, and When a slab strand is continuously pulled out from both ends of a horizontal mold, if the fracture position of this fracture surface with respect to the mold inner wall surface deviates from a plane perpendicular to the direction in which the slab strand is pulled out, the slab strand is pulled out at the ends of the horizontal mold. Press the strand in the width direction or thickness direction to create a space between the slab strand and the horizontal mold inner wall surface. It is characterized by adjusting the friction resistance and correcting the deviation of the fracture position.

For this reason, the fractured surface can be maintained at approximately medium heat and can always be maintained perpendicular to the drawing direction, the stability of the break point is improved by nearly 100%, and slabs with irregular surface textures can be obtained.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a part of an example of an adjusting device for carrying out the method of the present invention, FIGS. 2 and 3 are explanatory diagrams of modes of adjusting the breaking position according to the present invention, and FIG. A graph showing the relationship between breakout stability and casting speed when casting using the conventional method and the conventional method. Figure 5 is a general explanatory diagram of bi-directional drawing type horizontal continuous #1I construction. Figure 6 is It is an explanatory view of a fracture surface adjustment method of a conventional example. Code 10... Horizontal mold 11... Slab strand

Claims (1)

[Claims] 1) Molten steel is press-fitted into a horizontal mold that vibrates horizontally with a predetermined stroke, the molten steel is broken at a fracture surface at approximately the center of the horizontal mold and distributed to the left and right, and the distributed molten steel is While moving toward both ends of the horizontal mold, the slab is horizontally solidified to form a slab strand, and when these left and right slab strands are continuously pulled out from both ends of the horizontal mold, the fracture surface When the fracture position with respect to the inner wall surface of the horizontal mold deviates from a plane perpendicular to the drawing direction of the slab strand, the slab strand is pressed in the width direction or thickness direction at the end of the horizontal mold to separate the slab strand and the slab strand. A method for adjusting a fracture position during bidirectional drawing type horizontal continuous casting, characterized by adjusting the frictional resistance between the inner wall surface of the horizontal mold and correcting the deviation of the fracture position. 2) The molten steel is horizontally vibrated with a predetermined stroke, and the molten steel is distributed to the left and right at approximately the center of the horizontal mold into which molten steel is injected from approximately the center, and each molten steel is transferred toward both ends of the horizontal mold. It is cooled and solidified to form slab strands.
In this bi-directional drawing type horizontal continuous casting machine that continuously pulls out each slab strand, in addition to the pinch rolls for pulling out each slab strand continuously, there are also A bidirectional drawing mold characterized by being provided with a frictional resistance adjustment device that presses one strand from the width direction or thickness direction and adjusts the frictional resistance between each of the slab strands and the inner wall surface of the horizontal mold. Fracture position adjustment device during horizontal continuous casting.