JPH084810B2 - Slab width reduction method, mold and width reduction press machine - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for rolling a hot slab in a width direction in a rough rolling line for slabs (steel slabs). Width reduction without exception , as well as this method
It relates to a mold suitable for use and a width reduction press device .

[0002]

2. Description of the Related Art In recent years, slabs are often manufactured by a continuous casting method, and in order to increase production capacity, the width of the slabs can be adjusted to match the product width before rough rolling in a rolling line. It is being appreciated. For this width reduction, a forging press having a pair of molds 1 as shown in FIG. 4 is used. However, when the heavy reduction is performed, the slab S buckles and the slab S is buckled.
Twisting as shown in (b) may occur.

As a measure for preventing the above-mentioned buckling, it is general to dispose a pressing roll or the like on the upper and lower surfaces of the slab to be pressed (for example, JP-A-62-124044 and 63-2424).
02, JP-A-2-52105. However, it is difficult to completely prevent the buckling of the slab by taking such measures, and it is not preferable from the viewpoint of equipment and operation to install and drive a large number of pressing rolls.

[0004]

The object of the present invention is to prevent the buckling of the slab even when subjected to a large width reduction of, for example, 200 mm, and to eliminate the need for a large number of pressing rolls. Reduction method and this person
It is an object of the present invention to provide a mold and a width reduction press device suitable for use in a method .

[0005]

[Means for Solving the Problems] The present invention provides the following hot work (1):
Slab width reduction method, (2) width reduction mold (Fig. 1,
Fig. 2) and (3) width reduction press (see Fig. 3)
Is the gist.

(1) As a die for a forging press, 2 in the upper opening
Has a pressing surface that is inclined by ~ 10 degrees and has a rough surface pattern
Perform pressing by using a die and holding the top of the slab down
A method for reducing the width of a hot slab, which is characterized in that

(2) A surface that contacts the end surface of the slab (press
The parallel part (M1) whose surface is parallel to the transport path line,
Opened in a taper shape from the parallel part toward the entrance side of the slab
With a mold that performs width reduction of a slab consisting of an inclined part (M2)
Therefore, the parallel portion (M1) and the inclined portion (M2) are
The top opening is inclined 2 to 10 degrees, and the surface is rough
A mold characterized by having a pattern.

(3) Arranged on both sides of the slab to be transported
A pair of dies described in (2) above and this slab
Between the press that reduces in the width direction and the mold, and the top surface of the slab
A buckling prevention pressing member provided on the
Characteristic width reduction press machine.

The mold of the present invention is preferably operated with a friction coefficient μ between the surface (press surface) and the slab pressing surface of 0.3 to 0.5. For this reason, the press surface of the mold is roughened. . That is, the surface is roughened
Of.

FIG. 1 is a perspective view showing the shape of a mold 1 used in the present invention . FIG. 2 (a) is a plan view of the same mold,
2B is a vertical sectional view taken along the line AA of FIG. The surface (press surface) of the die that contacts the slab is composed of a parallel portion M1 and an inclined portion M2. The angle (α) formed by M1 and M2 may be about 10 to 15 degrees as in the conventional mold. As shown in the figure, the feature of this mold is that the pressing surface is inclined at an angle of θ (= 2 to 10 °) with respect to the vertical surface and is opened upward. In addition, in order to adjust the coefficient of friction as described above, in this example, the press surface is subjected to a large number of grooving processes.

FIG. 3 shows an embodiment of a slab width reduction method according to the present invention using the above-mentioned mold and a width reduction press device.
It shows a schematic configuration . In the figure, 2 is a roller table for slab transportation, 3 is a press for driving the mold 1, and 4 is a portion for holding the upper surface of the slab S for preventing buckling.
A material, for example, a roll. Two or more rolls 4 may be arranged in the slab traveling direction.

With the apparatus as shown in FIG. 3, the slab S is fed by a predetermined length and the press is driven to reduce the width by the die.

[0013]

The press surface of the normal width reduction die is perpendicular to the slab running surface. In this case, when pressed by the die's own weight, it tends to be pressed from top to bottom. Therefore,
Both ends of the pressed slab are lowered and the central part becomes higher, and buckling is likely to occur when the slab is strongly pressed.

As shown in FIG. 1, the mold of the present invention has an M
The press surfaces of 1 and M2 are inclined upward. When pressed with such a mold, a force from the bottom to the top is applied to both ends of the slab, the above-mentioned phenomenon does not occur, and buckling of the slab and accompanying twisting are reduced.

If the inclination angle θ of the mold is set to 2 to 10 degrees, the effect of preventing twist of the slab is insufficient if it is less than 2 degrees, and if it exceeds 10 degrees, the slab is pressed when pressed. The upward component force acting on the slab becomes too large, and the roll for pressing the upper surface of the slab must be made large.

As shown in FIG. 1, the pressing surface of the die is roughened by forming grooves or the like. This is to increase the coefficient of friction during width reduction described later. The coefficient of friction between the press surface and the end surface of the slab depends on the properties of the slab (material, scale adhesion state, etc.) and the usage conditions of the lubricant, but the state of the die surface has the greatest effect. The use of a lubricant is indispensable to prevent seizure under the width reduction of the hot slab, and the friction coefficient between the press surface and the slab end surface under normal general conditions is μ = 0.3 to 0.5. In order to achieve the above range, the pressing surface of the die must be processed to be rough. As a method thereof, in addition to the method of forming a groove on the press surface as shown in FIG. 1, there is a method of forming a net-like striped pattern by pressing.

When width reduction is performed using the above-mentioned mold, the coefficient of friction μ between the press surface of the mold and the slab end surface (abutting surface of the mold) is set in the range of 0.3 to 0.5. It is desirable to adjust. When the friction coefficient μ is less than 0.3, slip occurs between the slab and the pressing surface of the mold, the slab easily escapes upward, and an excessive force is applied to the pressing member on the upper surface of the slab. On the other hand, when the friction coefficient μ exceeds 0.5, seizure occurs between the die pressing surface and the slab end surface, resulting in severe die damage.

When the width reduction is performed, it is necessary to adjust the friction coefficient as described above and press the upper surface of the slab. As described above, the pressing surface of the mold is inclined upward so that the upward force acts on the slab pressed by this. Therefore, it is necessary to press the upper surface of the slab between at least the two molds with a pressing member such as a roll or a pressing plate. However, unlike the conventional method, a roll or the like for pressing the lower surface of the slab is not always necessary.
In this respect, the apparatus for carrying out the method according to the invention is simple.

According to the invention described above, the mold M1 and
The upward opening slope and rough surface pattern applied to the press surface of M2
Due to the action of the buckling prevention pressing member , buckling does not occur in the slab even if a large width reduction is performed, and a normal slab product as shown in FIG. 5A is obtained.

[0020]

EXAMPLE A slab width reduction test was conducted using the apparatus shown in FIG. Table 1 shows the test conditions, and Table 2 shows the test results.

As shown in Table 1, the slab under pressure is 270 mm
Has a constant thickness and various widths, and the width reduction amount is 1
It was changed from 50mm to 350mm. A mold having a shape satisfying the conditions of the present invention was used, and the coefficient of friction μ between the pressing surface of the mold and the slab end surface during rolling was adjusted to be 0.5. The pressing of the upper surface of the slab during rolling was performed by the roll 4 shown in FIG . 1 slab for each size
It is 00.

The numerical values shown in Table 2 are the number of slabs having a twist amount (h) shown in FIG. The numerical value in parentheses in Table 2 is the number of twist-generating slabs produced by the conventional width reduction method in which the die press surfaces are parallel and pressed.

From the results shown in Table 2, the twist-generating slab is remarkably small in any slab width and any width reduction amount according to the method of the present invention. For example, 3 slabs with a width of 1501 to 1600 mm
Even if it was rolled down with a width reduction of 50 mm, only 5 twists occurred. The remaining 95 were normal with h less than 200 mm. In the conventional width reduction method, such width reduction with a large reduction rate is almost impossible.

[0024]

[Table 1]

[0025]

[Table 2]

[0026]

As is clear from Table 2 of the embodiment, according to the width reduction of the slab according to the present invention, it is possible to obtain a sound slab with little twist even at a large reduction rate. Therefore, a wide range of width reduction can be selected, so that slabs of various widths can be manufactured from the original slab of the same width. The equipment for carrying out this method is relatively simple, and the practical value of the present invention is great in that respect as well.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of a mold of the present invention .

2 (a) is a plan view of the mold of FIG. 1, and FIG. 2 (b) is (a).
FIG. 5 is a vertical sectional view taken along line AA of FIG.

FIG. 3 shows a width reduction method and a width reduction press device of the present invention .
It is a perspective view shown.

FIG. 4 is a conceptual diagram of width reduction of a slab.

5A and 5B are diagrams showing a slab shape after width reduction, where FIG. 5A is a normal slab without twist, and FIG. 5B is a slab with twist.

Claims (3)

[Claims] 1. A die for a forging press, which has an opening of 2 to 10
And degree tilt, and using a mold having a pressing surface rough pattern is applied, hot width reduction method slab characterized by performing the press further suppressed slab top surface. 2. A conveying path line is a surface contacting the end surface of the slab.
Parallel part to the inlet side of the slab from this parallel part
The width of the slab consisting of a sloped part that opens in a taper toward
A die for rolling down, wherein the parallel portion and the inclined portion are
The top opening is inclined 2 to 10 degrees, and the surface is rough
A mold characterized by having a pattern. 3. One disposed on both sides of the slab to be transported.
A pair of the mold according to claim 2 and a width direction of the slab.
Installed between the press and the die, and on the upper surface of the slab.
And a buckling prevention presser member
Width reduction press device.