JPH11169902A - Pressing method for edging hot slab - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the time necessary for a time of press in the case the amount of edging is small by changing the period of a reciprocating motion in accordance with the amount of edging when the stroke of the reciprocating motion and the amount of edging of a slab satisfy a specified relationship. SOLUTION: The stroke S of the reciprocating motion and the amount ΔW of edging of the slab satisfy the relationship of the formula I. The α means a die movement distance which is necessary to accelerate to a speed at which the edging is possible after a die is started to move from the top dead center position. In the case the reciprocating motion of a press die is executed using a crank mechanism, it is preferable to take the rotational speed ωof the crank as a value which is expressed by the formula II. Where, ω0 and θpmax: the reference rotational speed of the crank and reference screw-down crank angle when the formula I is not satisfied by the relationship between the stroke S and the amount ΔW of edging, R: the radius of the crank, θ0: the crank angle corresponding to a prescribed time which is necessary to acceralation and deceleration for transporting the slab. By high-speed rotation, the contact time of the slab and the die is shortened and the life of the press die is prolonged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot slab width reduction press method in which a predetermined amount of slab is conveyed and a width reduction press is repeatedly performed by a width reduction press equipment for periodically reciprocating a press die. More particularly, the present invention relates to a hot slab width reduction press method capable of shortening the time required for one press and improving productivity when the width reduction amount is small.

[0002]

2. Description of the Related Art For example, when a material such as a slab is reduced in width, a vertical rolling mill has conventionally been used. However, since the vertical rolling mill cannot increase the amount of reduction per operation, several passes are required to reduce the amount to a predetermined amount, and there is a problem that the working efficiency is poor.

In order to improve the working efficiency, various proposals have recently been made to reduce the width of a slab by a press capable of increasing the amount of reduction each time.
As shown in FIG. 11, for example, as shown in FIG. 11, the width reduction press equipment 20 includes a pressing roll 22 for pressing the slab 10 conveyed on the table roller 12 from above and below (in a direction perpendicular to the paper surface) during width reduction. A pair of left and right (up and down in the figure) molds 24 for rolling down the slab 10 sandwiched by the presser rolls 22 in the width direction (the direction of the arrow A in the figure), and cranks for driving the molds 24 respectively And a slab 10 in the width reduction press equipment 20.
Is carried by the pinch rolls 2 provided on the entrance side and the exit side.
It is controlled by 8 and 30.

More specifically, as shown in the upper part of FIG.
With the slab 10 stopped, the mold 24 is reduced by the crank mechanism 26 to reduce the width, and then, as shown in the lower part of FIG. The operation of transporting by the pinch rolls 28 and 30 by the transport amount L is repeated.

[0005] The slab transport amount L at this time is usually, for example, as described in JP-A-63-242410.
It is constant regardless of the width reduction amount. In addition,
In 71609, it is described that when an abnormality of the width reduction press equipment is determined, control is performed so that the crank rotation speed is automatically reduced or the slab conveyance amount is reduced to recover the abnormal state. ing. In addition,
70104, the feed amount Lp of each pass is set to the average plate width Wm, the press entry side plate width W, the press exit side plate width W1, and the inclination angle of the mold inclined portion with respect to the parallel portion so that the slab can be formed with the minimum pressure of the press. When θ is set to θ (see FIG. 12), it is described that molding is performed by setting according to the following equation.

Lp = (0.8-0.9) Wm− (W−W1) / (2 tan θ) (3)

[0007]

However, conventionally, the slab conveyance amount L has not been determined from the viewpoint of improving productivity, and the speed of the reciprocating movement of the mold, that is, the crank rotation speed has been increased. In particular, when the width reduction amount is small, there is a problem that the extra time for pressing becomes unnecessarily long, which hinders an improvement in productivity.

FIG. 13 is a view showing a state in which the width reduction of the slab 10 by the mold 24 and the conveyance of the slab by a predetermined amount L are alternately performed. Here, only one side in the slab width direction is shown.
The mold 24 reciprocates periodically by a crank mechanism 26 (not shown in FIG. 13) in the direction of arrow A 'at a stroke S determined by the diameter of the crank. FIG.
In (A), the mold 2 indicated by a broken line, a solid line, and a dashed line
Reference numeral 4 denotes a state at the bottom dead center, a press start point, and a top dead center, respectively, and the state in which the mold 24 is at the bottom dead center (the state indicated by the broken line) is the width reduction in one cycle of the reciprocating movement of the press mold. Is the end of the process. While the mold moves from the bottom dead center position to the press start point (solid line state) through the top dead center position (dotted line), the slab 10 is transported in the direction of arrow B by the transport amount L. Here, the mold moving amount α from the top dead center position to the press start point position is a predetermined mold moving distance required to accelerate the mold 24 to a pressable speed.
Then, the slab 10 is pressed while the mold 24 moves from the press start point to the bottom dead center by the maximum width reduction amount Wmax / 2 on one side again. At this time, the shaded area is Press 1
It is an area that is deformed at a time.

In the conventional width reduction press method, FIG.
As shown in FIG. 3 (B), even when the one-side width reduction amount ΔW / 2 is small and the following equation (1) is satisfied, the bottom dead center position to the top dead center position ( The slab 10 is transported by the transport amount L until the slab 10 moves from the top dead center position to the direction approaching the slab by a predetermined moving amount α (solid line state).

S-α> ΔW / 2 (1)

Therefore, in the case of FIG.
From the state of the solid line 4 until the contact with the slab 10 to start the width reduction, the slab was not conveyed and the press was not performed.

In Japanese Patent Publication No. 4-70104, the slab conveyance amount is changed according to the above equation (3). However, since the slab conveyance amount is determined in order to minimize the press load, the dead time is not always required. We did not consider what would happen.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems. In particular, when the width reduction is small, the crank rotation speed is increased to reduce the time required for one press, and the productivity is reduced. The task is to improve

[0014]

SUMMARY OF THE INVENTION The present invention provides a width reduction press for a hot slab which repeatedly carries a predetermined amount of slab and a width reduction press by a width reduction press equipment for periodically reciprocating a press die. In the method, when the relationship between the stroke S of the reciprocating motion and the width reduction amount ΔW of the slab satisfies the expression (1), the cycle of the reciprocation is changed according to the width reduction amount ΔW, thereby achieving the object. Is solved.

S-α> ΔW / 2 (1) where α is a predetermined amount of metal required for the mold to start moving from the top dead center position toward the slab and accelerate to a speed at which the width can be reduced. Mold moving distance

Further, the present invention relates to a width reduction press method using a width reduction press equipment for reciprocating the press die by using a crank mechanism.
When the relationship between the width reduction amount ΔW of the slab and the slab satisfies the above equation (1), the above problem is solved by setting the crank rotation speed ω to the value shown in the equation (2).

Ω = [360−cos ⁻¹ {1− (ΔW / 2R)}] / (θpmax + 2θ0) × ω0 (2) where ω0 is the reciprocating stroke S of the mold and the width reduction of the slab. Reference crank rotation speed when the relationship of the amount ΔW does not satisfy the formula (1) R: crank radius θpmax: The relationship between the reciprocating stroke S of the mold and the width reduction ΔW of the slab does not satisfy the formula (1) Reference lower pressure crank angle θ0: Crank angle corresponding to a predetermined time required for acceleration and deceleration for slab conveyance

As described above, in the width reduction press,
Width reduction and slab conveyance are repeated. At this time,
When the relationship between the width reduction amount and the slab conveyance amount is illustrated by the rotation angle of the crank mechanism, the width reduction amount ΔW and the reciprocating stroke S of the mold do not satisfy the above equation (1), and the maximum width reduction amount W
FIG. 1A shows the case of max. Also, the width reduction Δ
When W and the stroke S of the reciprocating motion of the mold satisfy the above formula (1), FIG. 1B shows a case of a moderate width reduction, and FIG. 1C shows a case of a small width reduction. Thus, it can be seen that the necessary reduction area is narrow, and the transport area can be widened accordingly. In this case, the width reduction time depends on the width reduction amount, but slabs having various width reduction amounts exist in actual operation.
Therefore, when the width reduction amount is small and the expression (1) is satisfied, the width reduction time is also small, so that a large slab transport area can be obtained. The present invention has been made by paying attention to this point. In consideration of the rolling conditions of individual slabs, FIG. 1 (B) is designed to minimize the time required for one press within the equipment capacity range. As shown in FIG. 1) and FIG. 1C, when the width reduction amount is smaller than the maximum width reduction amount, the crank rotation speed is increased by an amount corresponding to the extra convey area to shorten the cycle of the reciprocating motion of the press die. As a result, the required time per press is shortened while securing the slab conveyance amount, and the productivity is improved.

As shown in FIGS. 2 and 3, the crank angle of the slab transfer area is θ, the crank angle corresponding to a predetermined time required for acceleration and deceleration for slab transfer is θ 0, and the one-side width reduction ΔW / 2. The crank angle of the required reduction area is θ
p, the maximum width reduction Wmax where the relationship between the reciprocating stroke S of the mold and the width reduction ΔW of the slab does not satisfy the equation (1).
The crank angle at the time (see FIG. 4 (A)) and the crank angle under the reference pressure are represented by θmax and θpmax, respectively, and similarly S and ΔW.
When the relationship (1) does not satisfy the expression (1), the reference crank rotation (angular) speed is ω0, and the width reduction amount according to the present invention is small (FIG. 4).
(See (C)), the crank rotation (angular) speed is ω (> ω0).
When the width reduction is at its maximum,
The relationship shown in FIG. 4A is established, and the relationship shown in FIG. 4B is established when the conventional width reduction amount is small. In the present invention, when the width reduction ΔW is small and the above-mentioned expression (1) is satisfied, the crank angle θ in the slab conveyance region is increased as shown in FIG. 4C. Then, the crank rotation speed ω is set to be higher than the reference crank rotation speed ω0, and the time (slab transfer time) Tm required for the crank to rotate by the angle θ of the slab transfer region becomes equal to the maximum width reduction Wmax. To Also, the crank angle θ0 corresponding to the margin time so that the margin time T0 required for deceleration or acceleration of the pinch roll becomes equal to the maximum width reduction amount Wmax.
'. Therefore, the slab transport time Tm and the rolling time T
p, the spare time T0, and the crank rotation period T are represented by the following equations.

Tm = θmax / ω0 (4) Tp = θp / ω (5) T0 = θ0 / ω0 (6) T = 360 / ω (7)

Here, the following relationship holds between the crank rotation period T, the slab transfer time Tm, the rolling time Tp, and the allowance time T0.

T = Tm + Tp + 2T0 (8)

By substituting the equations (4) to (7) into the equation (8) and solving for the crank rotational speed ω, the following equation is established.

Ω = {(360−θp) / (θmax + 2θ0)} ω0 (9)

Assuming that the width reduction amount is ΔW (mm) and the crank radius is R (mm), the reduction crank angle θp is expressed by the following equation.

Θp = cos ⁻¹ {1- (ΔW / 2R)} (10)

After all, when the width reduction amount is small, the crank rotation speed ω to be set according to the present invention is obtained by equation (2) obtained by substituting θp obtained by equation (10) into equation (9). be able to.

Corresponding to FIG. 4, the time of the die position when the width reduction amount is maximum when the width reduction amount is maximum, when the width reduction amount in the conventional crank rotation speed setting is small, and when the width reduction amount is small in the crank rotation speed setting according to the present invention. FIG. 5 shows an example of a typical change state. As is apparent from FIG. 5C, according to the present invention, when the width reduction amount is small, the required slab transfer time Tm is secured, and the crank rotation period is longer than that of the conventional FIG. 5B. T is shortened.

Θ 0 = 0 (degrees), R = 150 (mm), Δ
FIG. 6 shows an example of the relationship when W = 0 to 300 (mm) and θmax = 270 (degrees). In FIG. 6, the horizontal axis represents the width reduction Δ
W indicates the crank rotation speed ratio (ω / ω0) on the vertical axis, and it can be seen that the crank rotation speed ratio increases as the width reduction decreases. Also, this relationship
As is clear from the equations (9) and (10), it depends only on the width reduction.

As is apparent from FIG. 6, when the crank rotation speed at the time of the maximum width reduction is set as a reference, the average (the reduction amount is 10%).
15% at 0mm), 33% at maximum (rolling down almost 0mm)
Can be rotated at a high speed, and the time required for one press can be reduced.

[0031]

Embodiments of the present invention will be described below in detail with reference to the drawings.

In this embodiment, as shown in FIG. 7, for example, a slab width meter 40 provided on the entry side of the width reduction press equipment 20 is used.
And equipment having a controller 44 for controlling each drive motor M of the input pinch roll 28 and the output pinch roll 30 in accordance with the slab width detected by the slab width meter 40 and a command from the host computer 42. Applied. In the figure, reference numeral 50 denotes a rolling mill for rolling down the slab width-downed by the width-down pressing machine 20 in the thickness direction.

FIG. 8 shows a flowchart of the processing procedure in the present embodiment.

In this embodiment, first, step 10
At 0, for example, it is determined whether or not the width reduction amount ΔW is greater than the maximum width reduction amount Wmax determined according to the die stroke during width reduction. If the result of the determination is positive, it is necessary to perform the reduction by the maximum width reduction amount, so the process proceeds to step 110, and as in the conventional case, as shown in FIG. The crank mechanism is operated at the rotation speed ω0. In this case, the rotation cycle of the crank cannot be shortened.

On the other hand, if the result of the determination in step 100 is negative, and if the rotation period of the crank according to the present invention can be shortened, the process proceeds to step 120, where the calculation of the rolling crank angle θp by the above equation (10) is performed. Do.

Next, at step 130, the crank rotational speed ω to be set is obtained from the rolling crank angle θp calculated at step 120 by the equation (8).

Next, at step 140, the crank rotation speed is changed to ω.

In the above-described embodiment, the present invention is applied to the width reduction press device in which the reciprocating motion of the press die is performed by the crank mechanism. However, the application of the present invention is not limited to this. The present invention can be similarly applied to a width reduction press device that periodically reciprocates a press die by using a device other than a crank mechanism such as a hydraulic cylinder.

[0039]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS When the maximum width reduction Wmax = 300 mm, the reference crank rotation speed .omega.0 = 52 rpm, and the crank angle .theta.0 = 0 corresponding to the pinch roll acceleration / deceleration time, the width reduction .DELTA. Crank rotation speed ω
FIG. 9 shows an example of the relationship. As is apparent from the figure, when the distribution of the width reduction amount is constant and the average value is 100 mm, the crank rotation speed can be increased from 52 rpm to 60 rpm, and the rotation period of the crank can be reduced by 15%. it can.

FIG. 10 shows an example of the relationship between the slab length and the press rolling time. When the present invention is applied (solid line B), compared to the conventional case where the paper is conveyed at a constant speed (broken line A),
It is clear that the rolling time has been reduced. Further, since the rolling time per unit length is reduced, the longer the slab length is, the greater the shortening effect is.

[0041]

According to the present invention, it is possible to reduce the time required for one press when performing a width reduction press in a hot rolling factory. Further, by performing the high-speed rotation, the contact time between the slab and the mold during pressing can be shortened, and the life of the pressing mold can be extended.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a comparison of examples of the relationship between a slab conveyance area and a reduction area when a width reduction amount is maximum, middle, and small when explaining the principle of the present invention.

FIG. 2 is a diagram for explaining a calculation method for determining a crank rotation speed in the present invention.

FIG. 3 is a diagram showing a definition of a crank angle.

FIG. 4 is a graph for explaining the principle of the present invention by comparing examples of the relationship between the slab conveyance region and the reduction region when the width reduction amount is maximum, when the conventional width reduction amount is small, and when the width reduction amount according to the present invention is small. Diagram

FIG. 5 is a diagram corresponding to FIG. 4, showing a comparison of an example of a time change of a mold position when the width reduction amount is maximum, when the conventional width reduction amount is small, and when the width reduction amount according to the present invention is small.

FIG. 6 is a diagram illustrating an example of a relationship between a width reduction amount and a ratio of a crank rotation speed to a reference crank rotation speed when the present invention is applied.

FIG. 7 is a side view showing a configuration example of equipment to which an embodiment of the present invention is applied;

FIG. 8 is a flowchart showing an example of a processing procedure in the embodiment of the present invention.

FIG. 9 is a diagram showing an example of a relationship between a width reduction amount and a crank rotation speed in the embodiment of the present invention.

FIG. 10 is a diagram showing a comparative example of a relationship between a slab length and a press rolling time in a conventional example and an example of the present invention.

FIG. 11 is a plan view showing a configuration example of a width reduction press equipment.

FIG. 12 is a plan view for explaining the operation.

FIG. 13 is a plan view for explaining the operation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Slab 20 ... Width reduction press equipment 24 ... Die 26 ... Crank mechanism 28, 30 ... Pinch roll 40 ... Slab width meter 42 ... Host computer 44 ... Controller

Claims (2)

[Claims] 1. A width reduction press method for a hot slab in which a predetermined amount of slab is conveyed and a width reduction press is repeatedly performed by a width reduction press equipment for periodically reciprocating a press die. When the relationship between S and the width reduction amount ΔW of the slab satisfies the expression (1), the cycle of the reciprocating motion is changed according to the width reduction amount ΔW. . S-α> ΔW / 2 (1) where α is a predetermined mold moving distance required for the mold to start moving from the top dead center position toward the slab and accelerate to a speed at which the width can be reduced. 2. The method according to claim 1, wherein when the reciprocating movement of the press die is performed by using a crank mechanism, the rotational speed ω of the crank is set to a value represented by the equation (2). Slab width pressing method. .omega. = [360-cos- ¹ {1-(. DELTA.W / 2R)}] / (. theta.pmax + 2.theta.0) .times..omega.0 (2) where .omega.0 is the reciprocating stroke S of the mold and the width reduction .DELTA.W of the slab. Reference crank rotation speed when relationship does not satisfy formula (1) R: crank radius θpmax: reference when relationship between stroke S of reciprocating motion of die and width reduction ΔW of slab does not satisfy formula (1) Rolling down crank angle θ0: Crank angle corresponding to a predetermined time required for acceleration and deceleration for slab conveyance