JPH06122055A - Rolling reduction device for continuously cast billet - Google Patents

Abstract

PURPOSE:To provide a rolling reduction device for a continuously cast billet in which the deformation of rolling reduction rolls is reduced even when the thickness of a solidified shell is thicker than a specified thickness and the cost for equipment is made minimum. CONSTITUTION:The rigidity of rolling reduction rolls R5, R6, R7, R12, R13 and R14 arranged in the vicinity of the connecting part between connecting rods 24a, 24b, 24c and 24d, connecting arms 25a and 25b and rolling reduction frames 14a, 14b, 14c and 14d is set to be 70kg/mm<2> (offset yield stress 0.2% at 400 deg.C) and the rigidity of other rolling reduction rolls is set to be 28kg/mm<2> (offset yield stress 0.2% at 400 deg.C).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is a slab having a non-solidified layer at the center in the thickness direction (hereinafter referred to as "non-solidified slab").
The present invention relates to a continuous cast slab reduction device for processing thin slabs by continuously reducing a plurality of pairs of reduction rolls.

[0002]

2. Description of the Related Art In recent years, against the backdrop of an increase in the idea of labor saving and energy saving, an attempt has been made to omit the hot rolling process and directly and continuously produce a thin slab from a molten metal. As this method, there is a method of casting an unsolidified slab while continuously pressing it with a plurality of pairs of pressing rolls whose roll gaps gradually decrease from the mold to the downstream (hereinafter referred to as an unsolidified down-casting method). Are known.
As a reduction device for performing this unsolidified reduction casting method, a device provided with a reduction frame in which a plurality of pairs of reduction rolls with a gradually decreasing roll gap are arranged, and a reduction jack that supports the reduction frame and moves. Is known (see Japanese Patent Laid-Open No. 62-270257).

[0003] In the unsolidified rolling method, the unreacted layer is rolled down, so that the rolling reaction force acting on the rolling roll is smaller than that in the method in which the cast slab is rolled down. Therefore, the design withstand load of the rolling roll and the rolling frame can be reduced, which is advantageous in terms of equipment cost.

[0004]

The conventional rolling-down device described above does not pose a problem because the rolling reaction force is small when the solidified shell having a predetermined thickness and the non-solidified layer are stably present in the cast slab to be rolled down. A reduction can be achieved. However, if for some reason, the ability to cool the slab and other casting conditions change, and the thickness of the solidified shell also changes to become thicker than the planned thickness, the reduction roll An excessive rolling reaction force exceeding the design withstand load acts on. As a result, there is a problem that the pressing roll is deformed, which hinders subsequent casting.

In view of the above circumstances, it is an object of the present invention to provide a continuous cast slab reduction apparatus in which the deformation of the reduction roll is reduced and the equipment cost is kept to a minimum.

[0006]

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present inventors conducted various experiments and researches, and as a result of examining the deformation of the reduction roll, that is, the deflection amount of the reduction roll, Only the connecting means for connecting the reduction frame on which the roll is arranged and the reduction jack and the reduction roll arranged in the vicinity of the connecting portion with this reduction frame are largely deformed, and the deformation of the other reduction rolls is small. The present invention has been completed and the present invention has been completed.

[0007] Specifically, the continuous cast slab reduction device of the present invention is provided with a reduction frame in which a plurality of pairs of reduction rolls whose roll gaps are gradually reduced are arranged, and a connecting means connected to the reduction frame. In the continuous casting slab pressure reducing device supporting a pressure reduction frame and a moving pressure reduction frame moving device, the reduction roll arranged near the connecting portion between the reduction frame and the connecting means is the other reduction roll. It is characterized by having a higher rigidity than the rigidity.

[0008]

When the continuous casting slab reduction device of the present invention is used to reduce the continuous casting slab, when the thickness of the solidified shell of the continuous casting slab becomes thicker than expected, the rolling load for each reduction roll is equal to or more than the designed load capacity. Excessive rolling down reaction force acts. The reduction roll arranged near the connecting portion between the reduction frame and the connecting means has no escape area for the reduction stroke because the reduction frame is firmly supported by the reduction frame moving means via the connecting means. As a result, an excessive reduction reaction force acts on this reduction roll, but the rigidity of this reduction roll is higher than the rigidity of the other reduction rolls, so there is little deformation. On the other hand, in the other rolls for reduction, the reduction reaction force is alleviated by the elastic deformation of the reduction frame, and therefore the deformation is small.

Although it is possible to reduce the deformation of the reduction roll by increasing the rigidity of all the reduction rolls, it is not preferable to increase the rigidity of the reduction roll more than necessary because it increases the equipment cost.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the continuous casting slab reduction device of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory view showing an outline of a state in which an unsolidified slab is being pressed by the continuous casting slab pressing device of the present embodiment, and FIG. 2 is a partially enlarged view of the pressing device shown in FIG.

The continuous casting slab rolling down device 10 includes rolling down frames 14a, 1 in which a plurality of pairs of rolling down rolls 12 are arranged.
4b, 14c, 14d and the reduction frames 14a, 1
4b, 14c, and 14d, which can support and move the jacks 16a, 16b, 16c, and 1 for reduction.
6d and the reduction jacks 16a, 16b, 16c,
Fixed frames 18a and 18b to which 16d is fixed are provided, and the reduction frames 14a and 14d are also supported by support brackets 20a and 20b, respectively.

The reduction roll 12 comprises a plurality of pairs of 14 rolls R _{1 to} R ₁₄ , and the roll gaps of the reduction roll 12 are configured to gradually decrease. Also,
The reduction jacks 16a, 16b, 16c, 16d are reduction drive motors 22a, 22b, 22c, 22d, respectively.
Driven by. The reduction jacks 16a and 16d are portions near the _sixth roll R6, and the connecting rods 24a and 24d
and the reduction jacks 16b and 16c are connected to the reduction frames 14a and 14d, respectively.
In the third part close to the roll R _13, connecting rod 24b, 24
They are connected to the reduction frames 14b and 14c via c, respectively. Further, the connecting arms 25a and 25b connected to the connecting rods 24a and 24d are connected to the reduction frames 14b and 14c, respectively. Roll 12 for reduction
5th roll R ₅ , 6th roll R ₆ , 7th roll R
_{The materials of the 7th} , 12th roll R ₁₂ , the 13th roll R ₁₃ , and the 14th roll R ₁₄ are higher in rigidity than the other rolling rolls. Table 1 shows the material and characteristics of each rolling roll.

[0013]

[Table 1]

In this continuous casting slab reduction device 10, a slab in which a solidified shell 26 is formed in the surface layer by a mold (not shown) and an unsolidified layer 28 remains in the center in the thickness direction,
It is continuously rolled down by the rolling roll 12 and pulled out in the direction of arrow A, and a thin cast piece having a predetermined thickness is manufactured. next,
The results of performing unsolidified reduction casting using the continuous casting slab reduction apparatus 10 of the present example and a conventional continuous casting slab reduction apparatus as comparative examples will be described.

The structure of the conventional continuous casting slab reduction device is basically the same as the structure of the continuous casting slab reduction device 10 of this embodiment shown in FIG. The difference is that, as shown in Table 1, the No. 5 roll R ₅ of the continuous casting cast strip rolling device 10 of the present embodiment has higher rigidity than other rolling rolls, while the conventional rolling reduction is performed. All of the rolling rolls of the apparatus have the same rigidity, and the materials and characteristics are the same as the "other rolling rolls" shown in Table 1.

The unsolidified reduction casting conditions are steel type: medium carbon steel,
The casting speed was 1.2 m / min, the rolling reduction was 2 mm / roll pair, and the initial slab thickness was 110 mm. The rolling roll of the comparative example has rigidity enough to withstand the rolling reaction force when the slab has a predetermined unsolidified layer thickness. In each of the Examples and Comparative Examples, unsolidified pressure-reducing casting was performed four times, and the amount of deflection at the center of each reduction roll was examined after each end. The results are shown in Table 2. In addition, the rolling amount of the rolling for rolling before unsolidified rolling is 0.03 m for all rolling for rolling.
It was within m.

[0017]

[Table 2]

As shown in Table 2, in the case of this example, roll runout of 1 mm or more was not recognized in the four times of unsolidified pressure casting, and large roll deformation did not occur in the subsequent casting. On the other hand, in the case of the comparative example, the connecting rod 24
a, 24b, 24c, 24d, connecting arms 25a, 25
b and rolls for reduction R ₆ , R ₁₂ , R arranged in the vicinity of the connecting portions of the reduction frames 14a, 14b, 14c, 14d.
_{At 13} and R ₁₄ , as shown in Table 2, there was a case where roll runout of 1 mm or more occurred and a case where it did not occur. Casting No. In the case of No. 6, roll runout of 2 mm or more was observed in No. 13 roll R ₁₃ .

In the continuous cast slab reduction apparatus of this embodiment, since the reduction is carried out in a state where an unsolidified layer remains in the thickness direction central portion of the slab, the reduction reaction force acting on the reduction roll is It is smaller than the rolling method. Therefore, the design withstand load of the rolling roll and the rolling frame can be reduced, which is advantageous in terms of equipment cost. Also, when the thickness of the solidified shell becomes thicker than expected, it receives an excessive rolling reaction force.
Since the rigidity of only the pressing roll arranged near the connecting portion between the pressing frame and the pressing jack is increased, the roll deformation can be reduced without increasing the equipment cost.

In the present embodiment, the rigidity of the reduction roll is increased by changing the material, but the reduction roll can be formed by a method such as an internal water cooling structure or a split type roll. Increasing the rigidity of the roll is also included in the present invention. Further, in the present embodiment, the device for supporting and moving the reduction frame by the jack has been described, but the present invention is not limited to the jack, and includes, for example, a device for moving by a hydraulic cylinder or the like.

[0021]

As described above, in the continuous cast slab reduction device of the present invention, the connection portion between the reduction frame and the connecting means which receives an excessive reduction reaction force when the thickness of the solidified shell becomes thicker than expected. Since the rigidity of only the rolling roll arranged in the vicinity is increased, roll deformation can be reduced without incurring an extra increase in equipment cost, and the life of the rolling device can be extended. In addition, since the number of times the pressure reducing rolls are replaced and maintained can be reduced, casting efficiency is improved and stable operation can be achieved.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an outline of a state in which unsolidified slabs are rolled down by a continuously cast slab rolling down apparatus according to an embodiment of the present invention.

FIG. 2 is a partially enlarged view of the reduction device shown in FIG.

[Explanation of symbols]

 10 Continuous casting slab reduction device 12 Plural pairs of reduction rolls 14a, 14b, 14c, 14d Reduction frames 16a, 16b, 16c, 16d Reduction jacks 18a, 18b Fixed frame 20a, 20b Support brackets 22a, 22b, 22c, 22d Reduction drive motor 24a, 24b, 24c, 24d Connection rod 25a, 25b Connection arm 26 Solidified shell 28 Unsolidified layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shoji Itoyama 1 Kawasaki-cho, Chuo-ku, Chiba City Technical Research Division, Kawasaki Steel Co., Ltd. Industry Co., Ltd.

Claims (1)

[Claims] 1. A reduction frame moving device that supports and moves the reduction frame via a reduction frame in which a plurality of pairs of reduction rolls whose roll gaps are gradually reduced are arranged, and a coupling means connected to the reduction frame. In a continuous casting slab reduction device including and, the reduction roll disposed in the vicinity of the connection portion between the reduction frame and the connecting means has a higher rigidity than the rigidity of the other reduction rolls. A continuous casting slab reduction device characterized by: