JPS61154740A - Continuous casting machine for thin ingot - Google Patents

Abstract

PURPOSE:To prevent the deformation of metallic belts and the formation of an irregular-shaped ingot by forming the metallic belts into such a form that the radius of curvature of said belts in the casting space increases gradually so as to cool slowly a molten metal in the upper part and to cool quickly the same in the lower part with the specific area part of the ingot width as a boundary. CONSTITUTION:The traveling route of the part where the metallic belts 1, 2 face each other to delineate the casting space is designed into the traveling route where the arc has the specified radius or the radius of cuvature increases gradually in the midway from the specified curvature arc. The upper part is made into the slow cooling construction and the lower part into the quick cooling construction with the position D of 110% width with respect to the width of a belt support end C as a boundary. The deformation of the belts and the formation of the irregular-shaped ingot arising therefrom are thus prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a continuous thin slab casting machine. In particular, it is a narrow type of what is called a ``belt caster'' that directly casts thin slabs (sheet bars, etc.) with a thickness of 50 mm or less from molten metal (the following is an example of ``molten steel''). We propose a continuous casting machine.

(Prior Art) There are various types of belt casters for directly and continuously casting steel slabs such as sheet bars from molten steel, and the example shown in the second figure is a typical one. This belt caster has a plurality of guide rollers 3a, 3'a, 3'b, 3', respectively, while maintaining an interval for holding casting materials such as molten steel and solidified shells over a certain area.
b, 3c, 3'c, 3d.

A metal belt 1.2 that supports a pair of long side surfaces arranged opposite to each other and rotates through the metal belt 1.3'd.
．． 2 and a side plate 4 which is located between them and supports a short side surface that is in close contact with each other near each side edge, and has a configuration in which four sides are confined to form a tapered casting space.

(Problems to be Solved by the Invention) The above-mentioned conventional belt caster has a metal belt 1.2 that is the part that holds the casting material (molten steel 5a, solidified shell 5b).
is a constant circular arc from the position ■ of the upper guide rolls 3a, 3'a to the lower guide rolls 3d, 3'd (belt support end) to the 0 point in the middle, or a constant circular arc while gradually increasing the radius of curvature from the constant circular arc. The configuration was arranged so that a vertical travel path leading to a straight line was obtained so as to obtain an interval t.

In such a belt caster configuration, the gold mud belt 1.2 is tensioned by a hydraulic cylinder 6.6', and this belt tension is maintained by a film of cooling water jetted from a cooling pad 7 behind the belt. The bridge is adjusted with external forces such as molten steel static pressure belt tension and slab straightening force. However, the pressure adjustment is limited to the arc portions ① to ②.

That is, between 0 and 0, the belt tension can be balanced by controlling the water pressure and amount of cooling water injected from the cooling pad 7. However, in the straight line between ■ and ◎, the belt tension is Since the cooling pad 7 does not work effectively in the thickness direction of the cooling pad 7, there is a drawback that the flowing water film cannot be controlled by the cooling pad 7.

An object of the present invention is to prevent deformation of slabs due to inability to control the membrane pressure of a flowing water film as described above.

(Means for Solving the Problems) The present invention provides, as an effective means for solving the above-mentioned problems, a metal belt that rotates while maintaining an interval for holding molten metal and slabs over a certain area. , in a continuous casting machine in which a tapered casting space is constituted by a pair of side plates located between the metal belts and in close contact with them, the above-mentioned metal is applied between the molten metal scene of the casting space and the belt support end. The belt is arranged in such a way that it takes a running path that is an arc of constant curvature or a radius of curvature that gradually increases along the way from an arc of constant curvature. We propose a continuous casting machine for thin slabs, which is characterized by having a 61J construction.

(Function) The feature of the present invention is that from the scene level to the generation of a predetermined n-shell solidified shell: that is, the lower guide roller 36.3
The purpose is to temporarily install a metal belt in such a form that it maintains a running path with a constant curvature up to the position of the belt support end corresponding to part d', or that the running path has a radius of curvature that gradually increases along the way.

The so-called conventional straight line section is eliminated, and a continuous gradual straightening force is applied to the solidified shell that is generated.In this way, the distance from the molten steel surface level L to the slab width T becomes equal. Until then, the constant belt tension by the hydraulic cylinder 6.6' acts uniformly on the entire metal belt 1.2, and as a result, the bad 7.
It is now possible to control the film pressure of the cooling water jetted out from the
Eliminates defects in slab shape due to belt deformation.

The belt tension (the force with which the metal belt is urged against the cooling pad) can be calculated from the thrust of the hydraulic cylinder 6,6', so the hydraulics of the cooling water injected from the cooling pad 7 according to this belt tension, Adjust water pressure.

In this regard, in the conventional case, the flowing water concentrates on the straight part, resulting in a so-called middle bulge shape, but in the case of the present invention, since the casting section is curved over the entire length, the static iron pressure of the casting material,
Enables pressure control sufficient to support external forces such as straightening force on slabs.

In addition, in the present invention, the upper part of the short side of the slab is lined with refractory or further provided with a heating means to achieve slow cooling, while the lower part has a quenching structure of water-cooled jacket structure made of copper or the like. shall be.

The boundary between the slow cooling section and the rapid cooling section is gradually narrowed down to a position where the interval is finally 110% of the slab thickness (1). The reason for setting the boundary between the two at such a position is that we conducted the above experiment in a pilot plant and found that even if short side solidification was started from a position of 110% of the slab thickness, the casting speed was high and , the shell thickness produced is very smooth due to the short passage distance, so it does not affect the slab shape.
It was confirmed that draw casting is possible.

(Example) Fig. 1 shows a preferred embodiment M of the present invention, in which 1°2 is a metal belt, 3a, . . . 3' d are guide rollers,
4 is a side plate, 5a is molten steel, 5b is its solidified shell, 6 is a hydraulic cylinder, and 7 is a cooling pad.

The illustrated example has a configuration in which an arc of constant curvature is adopted for the running path of the part where the metal belts 1 and 2 face each other to form a casting space, and the width at the belt support end is 30 nua.
On the other hand, the width of the refractory and CIJ cold plate at position 3 was 33+nm. The solidified shell at the position ◎ was mainly formed only on the long side surface, and the solidified shell at the belt support end ◎ was completely solidified.

As a result of the experiment, no belt deformation or generation of deformed slabs due to the deformation of the belt was observed.

(Effects of the Invention) As explained above, according to the present invention, the water film pressure on the back surface of the metal belt can be controlled over the entire casting area, thereby eliminating deformation of the metal belt and generation of irregularly shaped slabs.

[Brief explanation of drawings]

FIG. 1 is a route map illustrating the continuous casting machine of the present invention, and FIG. 2 is a route map of a conventional continuous casting machine. 1.2...Metal belt 3a, ~3' d...Guide roller 4...Side plate
5a... Molten steel 5b... Solidified shell "
6...Hydraulic cylinder 7...Cooling pad Patent applicant: Kawasaki Steel Corporation Same applicant: Hitachi, Ltd. Figure 1 Figure 2

Claims (1)

[Claims] 1. A metal belt that rotates while maintaining an interval for holding molten metal and slabs over a certain area;
In a continuous casting machine in which a tapered casting space is formed by a pair of side plates that are located between the metal belts and are in close contact with the metal belts, the above-mentioned metal is used between the molten metal surface of the casting space and the belt support end. The belt is arranged in such a way that it takes a running path that is an arc of constant curvature or a radius of curvature that gradually increases along the way from an arc of constant curvature. A thin slab continuous casting machine characterized by a rapid cooling structure.