JPH0929301A - Method for sizing slab width by press - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the lowering of yield caused by the shape of a crop at the tip of a hot slab after edging, and the generation of a camber at the time of edging. SOLUTION: In this sizing method of slab width by a press in which the end faces in width of the hot slab are clamped with side guides and edging is executed on the upstream side of an edging press, the relation between the shape index S at the tip after pressing at the time of starting edging with the edging press used and the stop position L of the tip of the slab is preliminarily determined, the stop position of the tip of the slab is initialized in the control range of shape index S of the tip after pressing and edging is started. In this way, the lowering of yield of products and deterioration of threading performance in hot rolling are prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a slab width sizing method by a press for reducing the width of a hot slab by a width reduction press over the entire length and adjusting the width to a predetermined width.

[0002]

2. Description of the Related Art Width reduction of a hot slab extracted from a heating furnace by a width reduction press is a pair of press dies having a pressing surface in which the inlet side in the slab advancing direction is an inclined portion and the subsequent outlet side is a parallel portion. The mold is reciprocally moved in the direction perpendicular to the slab advancing direction, the slab is pressed over the entire length from the width end face, and compressed in the width direction to adjust to a predetermined width.

The width reduction of the hot slab by the width reduction press can obtain a large width reduction amount as compared with the roll width rolling, but a camber is formed on the hot slab while the width reduction of the hot slab is repeated. It may occur and bend.

Further, when the width of the hot slab is reduced by pressing, the slab is deformed into a fishtail shape or a tongue-shaped crop shape in which the widthwise central portion projects further in the longitudinal direction, which reduces the yield. Invite.

One of the causes of the camber caused by the width reduction press of the hot slab is that caused by the width reduction press itself, and as shown in FIG. 7, the press on both sides in the width direction of the hot slab 71 is performed. If the mounting position of the die 72 is displaced in the line direction (l ₁ > l ₂ ), the side of the slab 71 and the press die 72 that are closer to each other come into contact first, so that a rotational moment acts on the slab 71, causing the slab 71 to rotate. 71 becomes diagonal. The slanted slab 71 once slanted is the press die 7
Since the two surfaces are straightened so as to be parallel to the longitudinal direction of the line, a camber occurs because a bending force is applied in addition to the width reduction force.

The cause of the width reduction condition of the hot slab may be a difference in temperature conditions on both sides in the width direction of the hot slab. The hot slab is characterized by the characteristics of the heating furnace.
It is unavoidable that a temperature difference occurs in the width direction of the slab.
Particularly, in a commonly used walking beam type heating furnace, since an empty kiln is inevitably generated according to the rolling schedule, the temperature difference between both sides in the width direction of the hot slab becomes large.

When there is a temperature difference on both sides in the width direction of the hot slab, the compression amounts by the left and right press dies are different, the compression amount on the high temperature side is large, and the compression amount on the low temperature side is small. Therefore, if there is a temperature difference on both sides of the hot slab in the width direction, the compression range on the high temperature side will be lower than that on the low temperature side even if the left and right press dies are pressed down by eliminating the relative phase shift. Is expanded to the upstream side in the longitudinal direction and becomes asymmetrical, which causes a camber.

As a method of preventing the camber caused by the width reduction press of the hot slab, the feed force of the pinch roll provided on the downstream side of the width reduction press acts in the direction opposite to the camber bending direction. A method of correcting the camber that has occurred by changing the angle of the pinch rolls (Japanese Patent Laid-Open No. Sho-6
(Patent No. 1-222602), a width guide device having a guide roller is provided on at least one side before and after the line width direction of the width reduction press, and pressing is performed by the guide rollers on both sides so that the width center of the hot slab coincides with the press center. In order to prevent bending (Japanese Utility Model Laid-Open No. 62-96943, Japanese Patent Laid-Open No. 4-172101), the press dies arranged on both sides of the hot slab in the width direction are relatively moved in the line direction to heat the slab. The width of the hot slab is reduced by applying a bending force opposite to that of the camber to the hot slab and moving the side guides provided on the upstream side of the hot pressing to align with the center of the hot slab after width reduction. A method of correcting a camber caused by a temperature difference (Japanese Patent Laid-Open No. 3-254301) has been proposed.

Further, as a method of suppressing the yield decrease due to the crop shape of the front and rear ends caused by the width reduction press of the hot slab, the inclination angle of the inclined portion is 12 to 15 °.
While using the press die of No. 1, the molding of the end of the slab in the longitudinal direction is started at the inlet side inclined portion of the press die, and the feed amount of at least the first slab to the press die is set to 50.
A method of setting the thickness to 0 mm or less (Japanese Patent Laid-Open No. 64-22403) has been proposed.

[0010]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
The method disclosed in Japanese Patent No. 2602 is to provide a pinch roll on the downstream side of the width reduction press and correct the generated camber after that. When the camber is sandwiched between the upper and lower pinch rolls, it is very large. Since a force is required and a pinch roll is required on the downstream side of the width reduction press, the equipment becomes long and complicated, and there is a problem that workability is deteriorated by correcting the camber after width reduction.

Further, in the method disclosed in Japanese Utility Model Laid-Open No. 62-96943 and Japanese Patent Laid-Open No. 4-172101, when there is a difference in the temperature distribution in the width direction of the hot slab, the left and right press dies are used. Since the amount of compression is different, the center of the press and the center of the hot slab deviate, and this is constrained by the width guide device, which causes a new problem of bending due to this constraining force.

Further, the method disclosed in Japanese Patent Laid-Open No. 3-254301 solves the above-mentioned problems and can prevent the camber caused by the width reduction press of the hot slab, but the step resulting from the crop shape at the front and rear ends is not required. No consideration is given to the control of the drop in retention.

Furthermore, in the method disclosed in Japanese Patent Laid-Open No. 64-22403, the molding of the end portion in the longitudinal direction of the slab is started at the inlet side inclined portion of the press die in which the inclined angle of the inclined portion is 12 to 15 °. And, the feed amount of at least the first slab to the press die is 500 mm or less,
When the width reduction of the hot slab tip is started at the inclined part of the press die, the tip of the hot slab after wide reduction with a wide material exhibits a fishtail-like crop shape, and the reduction in yield due to the crop shape is suppressed. The effect is not enough. In addition, Japanese Unexamined Patent Publication
The method disclosed in Japanese Patent No. 4-22403 does not mention prevention of camber caused by a width reduction press.

An object of the present invention is to solve the above-mentioned drawbacks of the prior art, to suppress the yield reduction due to the crop shape of the tip of the hot slab after width reduction, and to suppress the occurrence of camber caused by the width reduction press. It is to provide a slab width sizing method by a press that can be performed.

[0015]

Means for Solving the Problems The present inventors have intensively studied and studied to achieve the above object. As a result, in the width reduction by the width reduction press of the hot slab extracted from the heating furnace, the tip shape after width reduction is influenced by the slab tip position at the start of width reduction, and the slab tip at the start of width reduction By setting the position within 100 mm before and after the intersection of the inclined part and the parallel part of the press die, preferably within 50 mm, it is possible to suppress the yield decrease due to the crop shape of the hot slab tip, and start the width reduction. When the slab tip position at this time is within 100 mm before and after the intersection of the inclined part and the parallel part of the press die, the camber caused by the width reduction press becomes a problem especially at the inclination part, but the side on the upstream side of the width reduction press has a problem. By installing a guide and pinching the hot slab at the start of width reduction, it is possible to suppress slab runout, suppress camber generation, and significantly reduce bending. To investigate the fact that you can, have reached to the present invention.

That is, the invention according to claim 1 of the present application is a slab width sizing method in which a width end face of a hot slab is sandwiched by side guides on the upstream side of the width reduction press to perform a width reduction, and the width reduction press is used in advance. Before starting the width reduction, the relationship between the tip shape index after pressing and the slab tip stop position at the start of the width reduction of the slab is obtained, and the slab tip stop position is initialized to the control range of the tip shape index after pressing. Is a slab width sizing method using a press.

Further, in the invention of claim 2 of the present application, in the slab width sizing method by a press in which the width end face of the hot slab is sandwiched by side guides on the upstream side of the width reduction press and the width is reduced, the slab tip stop position is set. The initial setting is ± 100 mm from the intersection of the inclined part and the parallel part of the press die, and
Set the upstream side guide width to the slab width ~ (slab width +
It is a slab width sizing method by a press, characterized in that the width reduction is started in a state of being clamped by 50 mm or less).

Further, in the invention of claim 3 of the present application, in the slab width sizing method by a press in which the width end face of the hot slab is clamped by side guides on the upstream side of the width reduction press, the width reduction is performed upstream of the width reduction press. A pinch roller equipped with a laser position detector and length measuring mechanism is installed on the side, and after detecting the slab tip by the laser position detector, the slab tip stop position is ± ± from the intersection of the inclined part and the parallel part of the press die.
Slab width sizing by a press, which is characterized in that it is conveyed by a table roller so as to be 100 mm, and the width reduction is started in a state where the upstream side guide set width is clamped by the slab width to (slab width + 50 mm or less). Is the way.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION In the invention of claim 1 of the present application,
The slab tip stop position at the start of width reduction was set as the control range of the tip shape index after pressing.The tip shape index after pressing and the slab tip stop depend on the press die conditions and reduction conditions of the width reduction press used. Because the relationship with the position is different,
The relationship between the tip shape index after pressing and the slab tip stop position is obtained in advance, and by setting the slab tip stop position within the control range of the tip shape index after pressing, the slab tip shape index S after width reduction is calculated. This is to keep it within the control range.

In the invention of claim 2 of the present application, the stop position of the slab tip is set to ± 100 mm from the intersection of the inclined portion and the parallel portion of the press die, because the press die condition and the roll reduction condition of the width reduction press to be used. Although the relationship between the tip shape index after pressing and the slab tip stop position differs depending on the situation, etc.
As shown in (a), in general, the larger the distance L from the intersection of the inclined portion 62 and the parallel portion 63 of the press die 61 to the slab 64 tip stop position, the more the penetration of deformation due to width reduction is in the slab 64 center. Since it reaches the part, the tongue-like shape of the slab tip is promoted. On the other hand, as shown in FIG.
As the distance L from the intersection of the inclined portion 62 and the parallel portion 63 of the press die 61 to the slab 64 tip stop position becomes smaller, the deformation cross-sectional area due to the width reduction becomes smaller.
The deformation is concentrated on both side surfaces, the ratio of metal flow to the tip side of the slab 64 which is the free end is increased, and the fishtail shape at the tip of the slab is promoted. From the above results, in order to suppress the slab tip shape index after width reduction within the control range,
The slab tip stop position was ± 100 mm from the intersection of the inclined part and the parallel part of the press die.

The distance L from the intersection of the inclined portion and the parallel portion of the press die where the slab tip stop position is -100 mm to +
Under the condition of 100 mm, the degree of deflection of the slab during width reduction is larger than that in the case of L> +100 mm. This has the function of suppressing the moment that the slab is about to rotate in the parallel portion of the press die when the slab tip stop position has a large distance L from the intersection of the inclined portion and the parallel portion of the press die. Therefore, the swing of the slab is not noticeable, but the distance L
When ≦ 100 mm, the contact length between the slab and the press die is short, and thus when the core is decentered, the rotation suppressing effect of the slab cannot be obtained, and as a result, the slab bending due to the occurrence of the camber after the width reduction is a problem. It is because

Further, in the present invention, the slab clamping condition by the side guide at the start of width reduction is set to slab width to (slab width + 50 mm or less) most when the set width of the side guide is the same as the slab width. Although it is effective, there is a high possibility that scratches will be generated on the slab side edge due to sliding, and practical centering is possible with a slab width of +50 mm or less.

In the present invention, the material of the side guide arranged on the upstream side of the width reduction press is not specified, but a general steel material such as machine structural steel is sufficient. Further, as a countermeasure against the scratches on the side surface of the slab by the side guide, it is sufficient to incorporate an embedded roll into the sliding surface of the side guide. The side guide can be driven by a hydraulic cylinder + servo mechanism or an electric cylinder. This side guide's automatic pressure control shaft requires two on one side in order to center the taper slab that occurs when changing the width during casting in continuous casting, but if the taper slab is not a target, one shaft is required. Is enough.

As the length measuring roll in the present invention, the upper and lower pinch rolls are arranged next to the side guide on the upstream side of the width reduction press, and automatic pressure control is performed hydraulically so as to follow the level fluctuation of the slab in the vertical direction. Is desirable. In this case, the length measurement may be performed on either the upper or lower roll.

A laser position detector is arranged between the length measuring roll and the press die. The laser position detector may be either a reflection type or a light emitting / receiving type, and the laser irradiation direction may be the vertical direction or the width direction with respect to the hot slab. It is desirable to irradiate the laser beam in the width direction from the side surface of the slab. From the time when the laser position detector detects the slab tip, the slab tip position is tracked by the length-measuring roll, and, for example, the distance L from the intersection of the inclined portion and the parallel portion of the press die to the slab tip stop position is L = The slab is transported so that it becomes zero.

According to the first aspect of the present invention, the relationship between the slab tip stop position and the tip shape index after pressing at the start of width reduction of the width reduction press to be used is obtained in advance, and the slab tip stop position is pressed. By initializing the subsequent control range of the tip shape index and starting the width reduction, it is possible to significantly suppress the yield decrease due to the crop shape of the slab tip.

According to the invention of claim 2 of the present application,
In the state where the slab tip stop position is initially set to ± 100 mm from the intersection of the inclined part and the parallel part of the press die, and the upstream side guide set width is clamped by the slab width ~ (slab width + 50 mm or less) By starting the width reduction,
The yield reduction due to the crop shape of the slab tip can be significantly suppressed, and the slab runout during width reduction can be suppressed to significantly reduce the occurrence of camber.

Further, in the invention of claim 3 of the present application, a pinch roller equipped with a laser position detector and a length measuring mechanism is provided on the upstream side of the width reduction press, and after detecting the slab tip by the laser position detector, The slab tip stop position is ± 100m from the intersection of the inclined part and the parallel part of the press die
It is conveyed by the table roller so as to be m, and the upstream side guide set width is from slab width to (slab width + 50
By starting the width reduction in a state of being clamped at (mm or less), it is possible to significantly suppress the yield decrease due to the crop shape of the slab tip, and suppress the slab runout during width reduction to prevent the occurrence of camber. It can be significantly reduced.

[0029]

【Example】

Example 1 Details of the method of the present invention will be described below with reference to FIG. FIG. 1 is an explanatory view of equipment arrangement for explaining a slab width sizing method by a press according to the present invention. In FIG. 1, 1 is a hot slab to be subjected to width reduction, 2
Is a pair of press dies having an inclined portion 3 and a parallel portion 4 for reducing the width of the hot slab 1. The hot slab 1 is brought into contact with and separated from the hot slab 1 by a crankshaft 5, and the hot slab 1 has a predetermined width dimension. Width reduction. Reference numeral 6 denotes a side guide for pressing the hot slab 1 arranged on the upstream side of the press die 2 for centering, and a pressing width by the hydraulic cylinder 7, that is, a setting width of the side guide 6 is adjustable. Has been done.

Numeral 8 is a pinch roll having a length measuring function, which is arranged between the side guide 6 and the press die 2, and is a hot slab 1
Is configured to be measured and output to the tip position control unit 9. Further, the pinch roll 8 is provided with an automatic pressure control mechanism (not shown) by a hydraulic mechanism so as to follow the vertical level fluctuation of the hot slab 1. Reference numeral 10 denotes a laser position detector arranged on the lateral side of the hot slab 1 between the pinch roll 8 and the press die 2. When the tip of the hot slab 1 is detected, it is output to the tip position controller 9. It is configured. The tip position control unit 9 determines the tip position of the hot slab 1 from the time when the tip detection signal of the hot slab 1 is input from the laser position detector 10 by the transport distance of the hot slab 1 input from the pinch roll 8. The hot slab 1 is conveyed so that the stop position L at the tip of the hot slab 1 is tracked and the intersection point of the inclined portion 3 and the parallel portion 4 of the press die 2, that is, L = 0.

By virtue of the configuration as described above, before the width reduction of the hot slab 1 is started, the hydraulic cylinder 7
Is operated to set the set width of the side guide 6 to the width of the hot slab 1 +25 mm, and then the hot slab 1 is conveyed by driving a table roller to center the hot slab 1. Next, the tip of the hot slab 1 is the laser position detector 1
When the tip detection signal of the hot slab 1 detected by 0 is input to the tip position control unit 9, the tip position control unit 9 receives the tip detection signal of the hot slab 1 from the laser position detector 10. From the above, the tip position of the hot slab 1 is tracked by the transport distance of the hot slab 1 input from the pinch roll 8, and the tip of the hot slab 1 reaches the intersection of the inclined portion 3 and the parallel portion 4 of the press die 2. Then, the table roller is stopped and stopped at the stop position L = 0 of the tip of the hot slab 1.

Thereafter, the crankshaft 5 is driven to start the width reduction of the hot slab 1 by the press die 2, and the width dimension is sequentially reduced to a predetermined width over the entire length of the hot slab 1. In this case, since the rear end portion of the hot slab 1 is pinched by the side guide 6, the runout of the hot slab 1 is suppressed even if there is a temperature deviation in the width direction of the hot slab 1. It is possible to prevent the occurrence of camber and suppress the bending after the width reduction. Further, by setting the tip stop position L of the hot slab 1 to L = ± 100 mm, preferably ± 50 mm or less, the hot slab 1 tip shape index S after width reduction can be suppressed to S = ± 10 mm or less. In the hot rolling, the tip shape index S before finish rolling can be suppressed to 50 mm or less, and the yield reduction due to the tip crop shape can be significantly reduced.

Example 2 Thickness 227 mm and width 1000 mm extracted from a heating furnace,
C: 1180 ° C. made of 0.05% general low carbon material
The hot slab of the slant angle 13 °, slant part length 800m
m, using a press die having a parallel portion length of 500 mm, the distance L from the intersection of the inclined portion of the press die and the parallel portion to the slab tip stop position is changed in the range of −100 mm to 230 mm, and 350 mm is applied by the width reduction press. Width reduction was performed, and the relationship between the tip shape index S after width reduction and the slab tip stop position L was determined. The result is shown in FIG. The tip shape index S after width reduction refers to the tongue-like or fishtail-like length of the slab tip after width reduction, as shown in FIG. 3 (a). The slab tip stop position L means the distance from the intersection of the inclined portion and the parallel portion of the press die to the slab tip stop position, as shown in FIG. 3 (b).

As shown in FIG. 2, the shape of the slab tip after width reduction varies depending on the slab tip stop position with respect to the press die position at the start of width reduction, and the slab crosses from the intersection of the inclined portion and the parallel portion of the press die. As the distance L to the tip stop position increases, the penetration of deformation reaches the slab center,
The tongue shape is promoted. On the other hand, the distance L from the intersection of the inclined part and the parallel part of the press die to the slab tip stop position
When the value is small, that is, when the value becomes negative, the deformation cross-sectional area is small, so deformation is concentrated on both sides of the slab, and the ratio of metal flow to the free end of the slab is increased, which promotes the fishtail-like shape. Tend to Therefore, in order to suppress the tip shape index S after width reduction within the control range, the distance L from the intersection of the inclined portion and the parallel portion of the press die to the slab tip stop position is ± 100.
It should be within mm, preferably within ± 50 mm.

Example 3 Thickness 227 mm and width 1000 mm extracted from a heating furnace,
C: 1180 ° C. made of 0.05% general low carbon material
In the hot slab of No. 2, the distance L from the intersection of the inclined part and the parallel part of the press die to the slab tip stop position is -90 mm to 2
It is changed in the range of 50 mm and 350 is applied by the width reduction press.
The effect on the amount of bending of the slab after width reduction depending on the presence or absence of the sandwiching pressure (sandwiching width 1025 mm) of the hot slab by the side guide in the case of the width reduction of mm was investigated. FIG. 4 shows the results.

As shown in FIG. 4, in the case of A in which the hot slab is not clamped by the side guide, when the slab tip stop position is L = 0 ± 100 mm, a large slab bend occurs and L is small. The bending amount tends to increase as much as possible. On the other hand, in the case of B in which the hot slab was pressed by the side guide, the slab bending amount after the width reduction pressing was stable at 10 mm or less regardless of the value of L. The slab tip shape after width reduction pressing is a fishtail shape when L <0, a tongue shape when L ≧ 0, and a tip shape index S after pressing of ± 10 mm indicates L = −50 mm to 50 mm.
Was between. By the way, when the hot slab is pinched by the side guide, the tip crop shape before the finishing stand of hot rolling has a tongue shape of S = + 5 mm when L = 0, and the tip shape control level. Of S ≦ 10 mm or less was a good level.

Example 4 Thickness 227 mm, width 1000 mm extracted from heating furnace,
C: 1180 ° C. made of 0.05% general low carbon material
In the hot slab, the distance L from the intersection of the inclined part and the parallel part of the press die to the slab tip stop position is fixed at 25 mm, and the side guide set width is set to the hot slab width to (hot slab width + 120 mm). The width was reduced by 350 mm by a width reduction press, and the influence on the amount of slab bending after width reduction was investigated. The result is shown in FIG.

As shown in FIG. 5, if the side guide set width is within the hot slab width to (hot slab width + 50 mm), the amount of slab bending after width reduction can be suppressed to a control level of 20 mm or less. It was

[0039]

As described above, according to the method of the present invention, it is possible to reduce the yield decrease due to the tip crop shape at the time of width reduction of the hot slab, and it is possible to suppress the slab bending after the width reduction and to suppress the slab bending. It is possible to prevent the decrease in yield due to the product camber and the deterioration of stripability in hot rolling.

[Brief description of drawings]

FIG. 1 is an explanatory view of equipment arrangement for explaining a slab width sizing method by a press according to the present invention.

FIG. 2 is a graph showing a relationship between a slab tip stop position L and a tip shape index S after width reduction in Example 2.

FIG. 3 is an explanatory diagram of a slab tip stop position L and a tip shape index S after width reduction, and FIG. 3A is a tip shape index S after width reduction.
And (b) are explanatory views of the slab front end stop position L.

FIG. 4 is a graph showing a relationship between a slab tip stop position L and a slab bending amount after pressing in Example 3.

FIG. 5 is a graph showing the relationship between (side guide set width-slab width) and the amount of slab bending after pressing in Example 4.

6A and 6B show changes in the tip shape depending on the slab tip stop position L at the start of width reduction. FIG. 6A shows a case where L is large and FIG. 6B shows a case where L is small.

FIG. 7 is an explanatory diagram of a slab bending mechanism after width reduction when the center position of the slab tip is displaced.

[Explanation of symbols]

 1 Hot Slab 2, 61, 72 Press Die 3, 62 Inclined Part 4, 63 Parallel Part 5 Crank Shaft 6 Side Guide 7 Hydraulic Cylinder 8 Pinch Roll 9 Tip Position Control Unit 10 Laser Position Detector 64, 71 Slab

Claims (3)

[Claims] 1. A slab width sizing method using a press in which the width end face of a hot slab is sandwiched by side guides on the upstream side of the width reduction press to perform width reduction, and after the width reduction of the width reduction press to be used in advance is started. The relationship between the tip shape index of the slab and the slab tip stop position is obtained in advance, and the slab tip stop position is initialized to the control range of the tip shape index after pressing, and the width reduction is started. Sizing method. 2. In a slab width sizing method by a press in which the width end face of a hot slab is sandwiched by side guides on the upstream side of the width reduction press and the width is reduced, the slab tip stop position is parallel to the inclined portion of the press die. ± 100m from the intersection with
A slab width sizing method by a press, characterized in that the width reduction is started in a state where the side guide setting width on the upstream side is clamped between the slab width and (slab width + 50 mm or less) by initial setting with m. 3. A slab width sizing method by a press in which the width end face of a hot slab is sandwiched by side guides on the upstream side of the width reduction press to perform the width reduction, and a laser position detector and length measurement are provided on the upstream side of the width reduction press. A pinch roller equipped with a mechanism is provided, and after detecting the slab tip by the laser position detector, the slab tip stop position is conveyed by the pinch roller so that the slab tip stop position is ± 100 mm from the intersection of the inclined part and the parallel part of the press die, Further, a slab width sizing method by a press, characterized in that the width reduction is started in a state where the upstream side guide set width is clamped by the slab width to (slab width + 50 mm or less).