JPS6115784B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for guiding continuously cast slabs.

An outline of conventional continuous casting equipment will be explained based on FIG. 1. Reference numeral 1 denotes a mold, and reference numeral 2 denotes a vertical bending mold conveyance path for the slab 3 which extends vertically downward from the mold 1, curves with a radius _R1 , and then extends horizontally, and includes a large number of rolls 2 ₁ , 2 ₂ , . . . It is composed of.

In the above configuration, the slab 3 pulled vertically downward from the mold 1 is mechanically bent at one point toward the bending center P side in the slab bending area α, and then
The cast slab is guided by R ₁ and then mechanically bent back to the side opposite to the bending center P in the slab straightening area β, and straightened straight at one point. Therefore, each roll 2 ₃ to _{2 8} , 2 ₂₁ to 2 in both the above ranges α and β
₂₆ , in particular, excessive reaction force due to bending and straightening will act on the roll pairs 2 ₅ , 2 ₆ and the roll pairs 2 ₂₃ , 2 ₂₄ corresponding to the bending and straightening points,
These rolls 2 ₃ - 2 ₈ , 2 ₂₁ - 2 ₂₆ and the segments that support each roll 2 ₃ - 2 ₈ , 2 ₂₁ - 2 ₂₆ need to be made strong, which increases the size of the structure and increases the cost of equipment. It's getting old.

Therefore, the present invention proposes a method for guiding continuously cast slabs that solves these problems.

Hereinafter, a first embodiment of the present invention will be described based on FIG. 2. Slab guide path 5 in this embodiment
is a vertical bending type, with bending area α and straightening area β
Inside, each roll 5 ₄ , 5 ₆ , 5 ₈ , 5 ₂₁ , 5 ₂₃ , which supports the surface A on the forced bending center side of the slab 3
5 ₂₅ as a driving roll, and each roll 5 ₃ , 5 ₅ , which supports the surface B of the slab 3 on the opposite side from the center of forced bending.
5 ₇ , 5 ₂₂ , 5 ₂₄ , 5 ₂₆ as driven rolls, and each of the driving rolls 5 ₄ , 5 ₆ , 5 ₈ , 5 ₂₁ , 5
₂₃ , 5 ₂₅ , the two upstream drive rolls 5 ₄ ,
5 ₆ , 5 ₂₁ , 5 ₂₃ to roll 5 ₄ to roll 5
The rotation speed of roll ₅ 23 is slowed down relative to roll 5 ₂₁ , and the rotation speed of roll 5 ₂₃ on the downstream side is slowed down.
₈ and 5 ₂₅ are used as braking rolls.

In the above configuration, the slab 3 pulled vertically downward from the mold 1 is bent by the pair of rolls 5 ₅ , 5 ₆ in the bending area α, and is compressed and guided in the direction of arrow C ₁ , so that the above two driving roll 5
_4,5 Brake roll 5 rotating even more slowly than _6
8 applies braking to the slab 3. In other words, the roll 5 ₄ is placed on the surface A on the forced bending center side.
The driving force F _1-1 caused by the rotation speed F 1-1 and the braking force E _1-1 caused by the rolls 5 ₆ having a slower rotation speed act in opposition to each other, and then the driving force F _1-2 caused by the rolls 5 ₆ acts in opposition to each other.
and the braking force E _1-2 from the braking rolls 5 _{and 8} act in opposition to each other, and as a result, the slab 3 is given a compressive force in the tangential direction on its one side surface A, and is naturally forced. It curves toward the bending center side (that is, toward the bending center P side). Next, this slab 3 is guided downward with a radius R ₁ , and the straightening area β
Inside, the slab is straightened by the pair of rolls 5 ₂₃ and 5 ₂₄ and compressed and guided in the direction of arrow C ₂ by a brake roll 5 ₂₅ that rotates more slowly than the two driving rolls 5 ₂₁ and 5 ₂₃ . Braking is added to 3. That is, the driving force F _2-1 by the roll 5 ₂₁ and the braking force E _2-1 by the roll 5 ₂₃ whose rotation speed is slower than this act on the surface A on the forced bending center side, and then the roll 5 The driving force F _2-2 due to ₂₃ and the braking force E _2-2 due to the brake roll 5 ₂₅ act in opposition to each other, and due to these, the slab 3 is given a contracting force in the tangential direction on its one side surface A. As a result, it naturally curves toward the center of forced bending (that is, the side opposite to the bending center P) and is guided in a straight line in the horizontal direction.

Next, the theoretical basis for the above embodiment will be explained by taking the rolls 5 ₅ to 5 ₈ in the bending region α as an example. Figure 3b shows the temperature distribution in the thickness direction at point B in Figure 3a;
At Hopoint, the temperature is 1500℃. Figures c and d show the stress distribution and strain distribution in the thickness direction at points A, B, and C in figure a, respectively, and large compressive stress and strain occur on surface A on the forced bending center side. . Therefore, even the outer surface of the slab 3 is in a high temperature state of 900 to 1000°C, and is in a state where it can be easily bent. Significant creep deformation occurs and shrinks, and the slab 3 bends by itself as shown by the imaginary line a in the same figure. In other words, by appropriately changing the torque of the rolls ₅₆ and brake rolls ₅₈ , the compressive stress can be increased or decreased, thereby making it possible to appropriately adjust the amount of bending of the slab 3. Further, by adjusting the torque, the state of strain change in the slab 3 can be adjusted, and the strain progression state for bending (or straightening) can be made optimal from the viewpoint of preventing crack generation.

A second embodiment of the present invention will be described based on FIG. The slab guide path 6 in this embodiment is a curved type using a circular arc mold with a radius of R ₁ , and each roll 6 ₁₅ supports the surface A of the slab 3 on the forced bending center side within the straightening zone β. , 6 ₁₇ , 6 ₁₉ are drive rolls, each roll 6 ₁₆ , 6 ₁₈ , 6 ₂₀ supporting the surface B of the slab 3 opposite to the forced bending center is a driven roll, and each of the drive rolls 6 ₁₅ is a driven roll. ，
Among 6 ₁₇ and 6 ₁₉ , the two drive rolls 6 on the upstream side
₁₅ and 6 ₁₇ , the rotational speed of the roll 6 ₁₇ is made slower than that of the roll 6 ₁₅ , and the downstream roll 6 ₁₉ is used as a braking roll.

According to the above configuration, as in the case of the first embodiment, within the correction area β, the roll pair 6 at the correction point
₁₇ and 6 ₁₈ , and is compressed and guided in the direction of arrow _C2 , the driving force F _2-1 by roll 6 ₁₅ and the roll 6 whose rotation speed is slower than this are applied to the surface A on the forced bending center side. The braking force E _2-1 caused by the roll _{6 17} acts in opposition to each other, and then the driving force F _2-2 caused by the roll 6 ₁₇ acts in opposition to each other.
and the braking force E _2-2 by the braking roll 6 ₁₉ act in opposition to each other, and as a result, the slab 3 is given a compressive force in the tangential direction on its one side surface A, and is naturally forced. It is curved toward the bending center side (that is, the side opposite to the bending center P) and is guided in a straight line in the horizontal direction.

A third embodiment of the present invention will be described based on FIG. The slab guide path 7 in this embodiment has a curved shape with multi-point straightening R ₁ , R ₂ , R ₃ , and the slab 3 cast in an arcuate mold with a radius R ₀ has a constant radius R ₀ .
After being guided downward in the correction area β,
Each roll 7 ₁₃ , 7 ₁₅ , 7 17 , 7 ₁₉ , 7 ₂₁ , 7 ₂₃ , _{7 25 ,} 7 ₂₇ supporting the surface A of the slab 3 on the forced bending center side
is the drive roll, and each roll 7 ₁₄ , 7 ₁₆ , 7 ₁₈ , which supports the surface of the slab 3 on the opposite side from the center of forced bending,
7 ₂₀ , 7 ₂₂ , 7 ₂₄ , 7 ₂₆ , 7 ₂₈ as driven rolls,
Furthermore, among the drive rolls 7 ₁₃ , 7 ₁₅ , etc., the seven upstream rolls 7 ₁₃ , 7 ₁₅ , 7 ₁₇ , 7 ₁₉ , 7
Slow down the rotation speed of ₂₁ , 7 ₂₃ , and 7 ₂₅ in this order,
The downstream roll ₇₂₇ is used as a brake roll.

According to the above configuration, as in the case of the first and second embodiments, the roll pair 7 ₁₅ of the correction points corresponding to the gradually increasing radius R ₀ <R ₁ <R ₂ <R ₃ within the correction region β , 7 ₁₆ , 7 ₂₁ , 7 ₂₂ , 7 ₂₅ , 7 ₂₆ and is compressed and guided in _{the two} directions of arrow C.
Rolls 7 ₁₃ , 7 ₁₅ , 7 are placed on the surface A on the forced bending center side.
Driving force F _2-1 , F due to ₁₇ , 7 ₁₉ , 7 ₂₁ , 7 ₂₃ , 7 _25
2-2 ,..., F _2-7 and opposing braking force E _2-1 ,
E _2-2 , ..., E _2-6 and the braking force E _2-7 by the brake roll 7 ₂₇ act on each other, and due to these, the slab 3 is given a compressive force in the tangential direction on its one side surface A. As a result, it naturally curves toward the center of forced bending (that is, the side opposite to the bending center P) and is guided in a straight line in the horizontal direction.

As described above, according to the method for guiding continuously cast slabs of the present invention, the driving force and the braking force are applied opposite to each other on the surface of the slab on the forced bending center side. By applying a compressive force in the tangential direction to the surface on the center side, the slab can be forced to bend naturally toward the center. That is, the deformation (bending straightening) of the slab can be promoted. Therefore, the bending or straightening force applied to each roll in the slab bending area and/or slab straightening area needs to be set extremely low, resulting in a reduction in power supply. In addition, since the reaction force is reduced, there is no need for a strong roll as in the past, and the structure can be downsized and the cost of equipment can be reduced.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of a conventional continuous casting equipment, Figs. 2 and 3 show a first embodiment of the present invention, Fig. 2 is a schematic diagram of a continuous casting equipment, and Figs. 3 a to d are FIG. 2 is a schematic diagram showing the relationship between bending of a slab, temperature, stress, and strain. FIG. 4 is a schematic diagram of continuous casting equipment showing a second embodiment of the present invention. FIG. 5 is a schematic diagram of continuous casting equipment showing a third embodiment of the present invention. 1...Mold, 3...Slab, 5, 6, 7...
Slab guide path, 5 ₄ , 5 ₆ , 5 ₂₁ , 5 ₂₃ , 6 ₁₅ ,
6 ₁₇ , 7 ₁₃ , 7 ₁₅ , 7 ₁₇ , 7 ₁₉ , 7 ₂₁ , 7 ₂₃ , 7 ₂₅ ...
... Drive roll, 5 ₈ , 5 ₂₅ , 6 ₁₉ , 7 ₂₇ ... Brake roll, α ... Bending region, β ... Straightening region, A ... Forced bending center side surface.

Claims (1)

[Claims] 1. Supporting the forced bending center side of the slab in the slab bending area and/or slab straightening area of the above-mentioned route in continuous casting equipment where the slab guide path is a vertical bending type or a curved type. Each roll is a driving roll, and each roll that supports the surface opposite to the forced bending center of the slab is a driven roll, and among the above driving rolls, the rotation speed of the rolls other than the most downstream one is from upstream to downstream. by slowing down the
A continuously cast slab characterized by compressing and guiding the slab to the downstream side, applying braking to the slab by using the most downstream drive roll as a brake roll, and naturally bending the slab toward the center of forced bending. guidance method.