JPH0760323A - Finish rolling method - Google Patents

Abstract

PURPOSE:To stably obtain a plate metal having a target plate crown with an excellent sectional profile. CONSTITUTION:At the time of finish rolling by using a tandem rolling mill having over than two actuators for controlling plate crown and shape, an objective value of the crown is set at two points, at least, of lateral direction of the plate metal, and the actuators are regulated so that the crowns of two points at the outlet side of the rolling mill are matched to the objective crown.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a finish rolling method, and in particular, it aims to secure a target plate crown after finish rolling and to stably obtain a plate material having a good plate shape and cross-sectional profile. It is a thing.

As a method of rolling so as to secure a target plate crown on the exit side of a finish rolling mill while taking into consideration the plate shape, the plate shape (elongation difference ratio) at each stand is set within an allowable value. It is disclosed in, for example, Japanese Patent Laid-Open No. 61-42409, in which the target crown is predetermined and the actuator is set and adjusted in each stand so that the target plate crown can be obtained in the final stand. It was common to have something like.

Here, the shape of the plate is defined by the following formula (1), and the plate crown is defined by the formula (2) (the defining point of the plate crown is as close to the plate end as possible by the sensor). It is a close position, and it is common to perform quality control of kurunou at this position).

Δε _i = ξ _i (CR _i −CR _i-1 ) CR _i = C _i / h _i --- (1) Δε: elongation difference ratio, ξ: shape change coefficient, CR: crown ratio, C: Plate crown h: Plate thickness, i: Stand number (i = 0 represents the seat bar) C = (h _C −he) / h _C --- (2) h _C : Plate thickness at the center of plate, he: Plate thickness at plate edge

[0005]

By the way, in the conventional rolling including the above-mentioned method, it is usual to give the target value of the plate crown of the final stand to only one point in the plate width direction. Since the plate crowns at other positions in the direction are not considered at all, there are problems as described below.

That is, there are roll benders, roll shifts (giving various initial crowns to rolls), roll cloths, etc. as actuators for controlling the plate crown and shape, but in the width direction of the plate to be rolled. When focusing on the whole area, the influence of these actuators on the plate crown may be different, and the thermal crown grows as the rolling cycle progresses, and further the wear of the roll gradually progresses. Therefore, even when the same actuator is used, it acts differently in the plate width direction.

Therefore, when the target value of the crown is given to only one point in the plate width direction and the set value is calculated to set and adjust the actuator, the desired plate crown is also set in other portions in the plate width direction. It was not always possible to obtain a good plate profile, and it was difficult to stably secure a good plate profile.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to secure a target plate crown on the exit side of a final stand and to obtain a good shape and profile in finish rolling of a plate material using a tandem rolling mill. The present invention proposes an advantageous method for obtaining a plate material having the same.

[0009]

According to the present invention, when a tandem rolling mill having two or more crown and shape control actuators is used for finish rolling, the target value of the plate crown is set at at least two points in the width direction of the plate. In the finish rolling method (first invention), the actuator is set so that the above two points of the plate crown match the target plate crown on the exit side of the tandem rolling mill. Yes, it is especially preferable to set each actuator according to the following procedure.
(Second invention). Note 1. Target plate crowns are given as C _m1 and C _m2 at positions X ₁ and X ₂ along the width direction from the end of the plate member, respectively. 2. The actuator with the smaller control capability is fixed to the maximum control amount A _1max , and X ₁ along the width direction from the edge of the plate
The setting values of the other actuators are calculated so that the plate crown at the position of becomes the target plate crown C _m1, and the plate crown C _m2max at the position of X ₂ along the width direction from the end of the plate material is calculated. 3. The actuator with the smaller control capability is fixed to the minimum control amount A _1min , and X ₁ along the width direction from the edge of the plate
The set values of other actuators are calculated so that the plate crown at the position of becomes the target plate crown C _m1, and the plate crown C _m2min at the position of X ₂ along the width direction from the end of the plate material is calculated. 4. The target plate crown C _m2 is C _{m2min ≤C m2 ≤C m2max}
If the following is satisfied, the control amount A ₁ of the actuator with the smaller control capability is set to A ₁ = A _1min + (A _1min −A
_1max ) ・ (C _m2 −C _m2min ) / (C _m2min −C _m2max ) Fixed to the value obtained and X along the width direction from the edge of the plate material
The set values of the other actuators are calculated so that the crown of ₁ becomes the target plate crown C _m1 . 5. Target strip crown C _{m @ 2} described above, in the case of _{C m2} ≦ C m2min is in the A ₁ = A _1min, also in the case of _{C m2} ≧ C m2max is in the A ₁ = A _{1 max,} the end of the plate The setting values of the other actuators are calculated so that the crown of X ₁ along the width direction from the portion becomes the target plate crown C _m1 .

Further, according to the present invention, when finishing rolling using a tandem rolling mill having a crown and a shape control actuator, the allowable range of the plate crown is set to at least one of the two points in the width direction of the plate material, Set the target value of the strip crown to the other point, and set the actuator so that the strip crown of one point is within the allowable range and the strip crown of the other point matches the target strip crown on the exit side of the tandem rolling mill. It is preferable that the setting of each actuator is performed according to the following procedure (the fourth invention). Note 1. Target value C _e of the plate crown near the width end of the plate material
In the range of C _{emin to} C _emax , and the target value of the plate crown of the quarter portion is given as C _q . 2. When the target value of the plate crown near the width end of the plate material is C _emin , the set value of each actuator is calculated, and the plate crown C _qmin in the quarter portion at that time is calculated. 3. When the target value of the plate crown near the width end of the plate material is C _emax , the set value of each actuator is calculated, and the plate crown C _qmax in the quarter part at that time is calculated. 4. The target value C _q of the plate crown in the quarter part is
When C _qmin ≦ C _q ≦ C _qmax is satisfied, the target value C _e of the plate crown in the vicinity of the width end of the plate is set to C _e = C
_emin + (C _emin −C _emax ) ・ (C _q −C _qmin ) / (C _qmin
-C _qmax ) and set value of each actuator is calculated. 5. The target value C _q of the plate crown in the quarter part is
When C _q ≤ C _qmin , C _e = C _emin , and C
_{When q} ≧ C _qmax , C _e = C _emax is set and the set value of each actuator is calculated.

[0011]

[Function] With a 7-stand tandem rolling mill equipped with a roll bender and roll cloth, which are actuators for controlling the plate crown and shape, the plate thickness is 4.5 mm and the plate width is 1550 mm.
The target plate crown at the final stand is 25mm from the plate edge.
If the roll bender control ability is set to the maximum and minimum in all stands and rolling is performed by adjusting only the roll cloth in each case in order to roll to 30 μm at the position of In either case, as shown in Fig. 1, from the plate edge
The target plate crown is 30 μm at the 25 mm position
Can be secured.

However, if the control ability of the roll bender is maximized in all the stands, the plate thickness of the quarter portion becomes thicker, and conversely, if the control ability of the roll bender is minimized, the quarter portion becomes thicker. The plate thickness becomes thinner, and the difference becomes about 20 μm, and it is clear that the influence of the roll bender and the roll cloth on the crown at each position in the plate width direction is different.

As described above, when there are two or more plate crown and shape control actuators, in the conventional method in which the target plate crown is one point, the combinations of actuators for obtaining the target plate crown are endless. Although present, it is inevitable that the combination will result in different plate crowns in other regions.

In the present invention, for example, target plate crowns are given to at least two points in the plate width direction, such as the end part of the plate and the quarter part, and the actuator is adjusted so as to match the target plate crown. The setting is performed, and according to this, a desired plate crown can be secured, and a plate material having a good profile can be finished.

The actuator can be set according to the following procedure.

First, the target plate crown at the position X ₁ along the width direction from the end of the plate member is C _m1, and the target plate crown at the position X ₂ along the width direction from the end of the plate member is C _m2 . To do. Then, for example, the actuator with the smaller control capability of the two actuators is
o.1, and when the actuator with the larger control capacity is No. 2, the maximum value (maximum control amount) of the control capacity of actuator No. ₁ is A _{1 max} , and the minimum value (minimum control amount) is A _{1 min} .

Actuator No. 1 A _{1 max} and A
For each _{1 min} , the set value of actuator No. 2 is determined so as to achieve the target plate crown C _m1 at the position X ₁ from the plate end. Then, at that time, the plate crown at the position X ₂ from the plate end portion is C _m2max , C
_m2min , the target plate crown C _m2 is C _m2max ≤ C _m2 ≤
Determine whether C _mmin is satisfied. When this condition is satisfied, the control capacity of actuator No. ₁ is fixed to the control amount A ₁ obtained by the following equation, and the crown of X ₁ along the width direction from the end of the plate is the target plate crown C _m1. It is necessary to find the set value of the actuator No.2 so that and adjust the actuator accordingly.

A ₁ = A _{1 min} + (A _1min -A _max ) (C _{m2
-C m2min) / (C m2min -C} m2ma x)

The target plate crown C _m2 is C _m2 ≤C
_In the case of _m2min , A ₁ = A _1min , and C _m2 is C _m2
When ≧ C _m2max , A ₁ = A _1max is set, and the crown of X ₁ along the width direction from the end of the plate material is the target plate crown C.
The set value of actuator No. 2 should be calculated so that it becomes _{m 1} .

The procedure for calculating the set value when setting the actuator is as shown in FIG.

Next, using a 7-stand tandem rolling mill having a crown and an actuator for shape control,
When the finished plate thickness is 3.0 mm, the plate width is 1250 mm, and the actuator is adjusted at the beginning and the latter half of the rolling cycle so that the plate crown on the exit side of the final stand is rolled to 30 μm at the position 25 mm from the plate edge. The cross-sectional profile of the plate material is shown in FIGS.

In any case, the target value of the plate crown of 30 μm can be achieved at the position 25 mm from the plate edge. However, in the case where the actuator was adjusted in the early stage of the rolling cycle, although the ideal plate profile was obtained, the adjustment in the latter half of the rolling cycle in which thermal crown and wear had grown resulted in the plate thickness of the quarter portion being It is so thin that a good plate profile cannot be obtained.

FIG. 5 shows a cross-sectional profile of the plate on the exit side of the final stand when the actuator is adjusted in the latter half of the rolling cycle with the target plate crown at a position 25 mm from the end of the plate being 10 μm.

In this case, it can be seen that the crown of the quarter portion is reduced and the cross-sectional profile is improved. Therefore, by giving the target value of the plate crown also to the quarter portion and setting the target of the plate crown in the vicinity of the plate end within the allowable range of quality control, it is possible to improve the sectional profile of the plate.

At least one of the two points in the width direction of the plate material is set with the allowable range of the plate crown, and the other point is set with the target value of the plate crown, and one point of the plate crown is set on the exit side of the tandem rolling mill. In order to adjust the actuator so that the plate crown is within the allowable range and the other plate crown matches the target plate crown, the following procedure may be followed.

The target value of the plate crown in the vicinity of the width end of the plate member is set to the range of C _{emin to} C _emax , and the target value of the plate crown of the quarter portion is set to C _q . Then, when the target values of the plate crown near the plate end portion are C _emin and C _emax , the set values of the actuators are calculated, and the plate crown in the quarter portion at that time is _defined as C _qmin and C _qmax, and C _qmin By adjusting the actuator so as to satisfy the condition of ≦ C _q ≦ C _qmax , the crown in the vicinity of the plate end portion is kept within the target range, and the plate crown of the quarter portion is set as the target value.

At this time, the concrete target value C _e of the plate crown near the width end of the plate material is C _e = C _emin + (C _emin −C
_emax) become _{(C q -C qmin) / (} C qmin -C qmax).

FIG. 6 shows the procedure for calculating the set value when adjusting the actuator.

When C _q ≤ C _qmin and C _q ≥ C _qmax , the plate crown of the quarter cannot be set as the target value, but C _e = C _emin and C _e = C _emax , respectively. The cross-sectional profile can be improved with.

[0030]

【Example】

Example 1 A target plate crown is set at two points in the plate width direction of the material to be rolled (the target plate crown is at a position 25 mm from the plate end).
30 μm, quarter (plate width x 0.15 from plate edge)
Tandem rolling mill with two actuators, a work roll bender and a roll cloth.
By applying roll cloth to the 1st to 7th stands), finish rolling is performed while adjusting each actuator so that the above target plate crown can be obtained in 85 rolling cycles.
The crown and shape of the obtained plate material were investigated.

The result is compared with the result when the target plate crown is set at one point in the plate width direction, the bender is fixed to a constant value, and rolling is performed by adjusting only the roll cloth (conventional method). 7 shows.

At a position 25 mm from the edge of the plate, the target plate crown can be obtained by any of the methods, but in the conventional method, the crown of the quarter part increases as the rolling cycle progresses, and the target value is set. I couldn't get it. On the other hand, according to the method of the present invention, the crown of the quarter portion can be set to the target value regardless of the progress of the rolling cycle, and it has been confirmed that a plate material having stable quality for a long period can be rolled.

Example 2 Target plate crowns are set at two points in the plate width direction of the material to be rolled (the target crown is 0 to 25 mm from the plate edge).
30 μm (allowable range in quality control), quarter (0 μm at plate width from plate edge × 0.15), and a 7-stand tandem rolling mill (work roll bender and roll cross actuator) The roll bender is applied to the 7th stand and the roll cloth is applied to the 1st to 7th stand), and the finish rolling is performed by adjusting the actuator so that the above target crown can be obtained in 85 rolling cycles. , Investigated the plate crown.

The results are shown in FIG. 8 and the results in the case of rolling (conventional method) in which the actuator is adjusted by giving only the target value of the plate crown in the vicinity of the plate end portion are shown in FIG.

In the conventional method, the crown of the quarter portion increases as the rolling cycle progresses, and it becomes difficult to obtain the target plate crown and the profile of the plate tends to deteriorate. It was confirmed that not only the plate crown at the end of the plate but also the plate crown of the quarter part can be set to the target value, and the cross-sectional profile of the plate can be made good.

[0036]

As described above, according to the present invention,
Plate crown, in finish rolling using a tandem rolling mill having two or more actuators for shape control, not only it is possible to secure a target plate crown, it is possible to improve the cross-sectional profile,
It can fully handle plate materials that require strict product quality.

[Brief description of drawings]

FIG. 1 is a diagram showing a width direction plate thickness distribution of a plate material after rolling.

FIG. 2 is a diagram showing a procedure for calculating a set value of an actuator.

FIG. 3 is a diagram showing a width-direction plate thickness distribution of a plate material after rolling.

FIG. 4 is a diagram showing a width direction plate thickness distribution of a plate material after rolling.

FIG. 5 is a diagram showing a width-direction plate thickness distribution of a plate material after rolling.

FIG. 6 is a diagram showing a procedure for calculating a set value of an actuator.

FIG. 7 is a diagram showing a result of examining a plate crown of a quarter portion of a plate material.

FIG. 8 is a diagram showing a result of examining a crown of a plate material after rolling.

FIG. 9 is a diagram showing a result of examining a crown of a plate material after rolling.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication location 8315-4E B21B 37/00 116 B 8315-4E 116 J 8315-4E 117 B (72) Inventor Isobe Kunio 1 Kawasaki-cho, Chuo-ku, Chiba, Chiba Pref., Technical Research Division, Kawasaki Steel Co., Ltd. (72) Inventor Junzo Nitta 1 Kawasaki-cho, Chuo-ku, Chiba, Chiba Kawasaki Steel Co., Ltd. Chiba Works

Claims (4)

[Claims] 1. When finishing rolling using a tandem rolling mill having two or more plate crowns and shape control actuators, target values of the plate crowns are set at at least two points in the width direction of the plate material, and tandem rolling is performed. A finish rolling method characterized in that each actuator is set so that the plate crowns of the two points match a target plate crown on the exit side of the rolling mill. 2. The method according to claim 1, wherein each actuator is set according to the following procedure. Note 1. Target plate crowns are given as C _m1 and C _m2 at positions X ₁ and X ₂ along the width direction from the end of the plate member, respectively. 2. The actuator with the smaller control capability is fixed to the maximum control amount A _1max , and X ₁ along the width direction from the edge of the plate
The setting values of the other actuators are calculated so that the plate crown at the position of becomes the target plate crown C _m1, and the plate crown C _m2max at the position of X ₂ along the width direction from the end of the plate material is calculated. 3. The actuator with the smaller control capability is fixed to the minimum control amount A _1min , and X ₁ along the width direction from the edge of the plate
The set values of other actuators are calculated so that the plate crown at the position of becomes the target plate crown C _m1, and the plate crown C _m2min at the position of X ₂ along the width direction from the end of the plate material is calculated. 4. The target plate crown C _m2 is C _{m2min ≤C m2 ≤C m2max}
If the following is satisfied, the control amount A ₁ of the actuator with the smaller control capability is set to A ₁ = A _1min + (A _1min −A
_1max ) ・ (C _m2 −C _m2min ) / (C _m2min −C _m2max ) Fixed to the value obtained and X along the width direction from the edge of the plate material
The set values of the other actuators are calculated so that the crown of ₁ becomes the target plate crown C _m1 . 5. Target strip crown C _{m @ 2} described above, in the case of _{C m2} ≦ C m2min is in the A ₁ = A _1min, also in the case of _{C m2} ≧ C m2max is in the A ₁ = A _{1 max,} the end of the plate The setting values of the other actuators are calculated so that the crown of X ₁ along the width direction from the portion becomes the target plate crown C _m1 . 3. When finishing rolling using a tandem rolling mill having a crown and an actuator for shape control, an allowable range of the plate crown is set at one of at least two points in the width direction of the plate material, and another point is set. Set the target value of the strip crown, and set the actuator so that the strip crown of one point is within the allowable range and the strip crown of the other point matches the target strip crown on the exit side of the tandem rolling mill. A finishing rolling method characterized by the above. 4. The method according to claim 3, wherein the setting of each actuator is performed according to the following procedure. Note 1. Target value C _e of the plate crown near the width end of the plate material
In the range of C _{emin to} C _emax , and the target value of the plate crown of the quarter portion is given as C _q . 2. When the target value of the plate crown near the width end of the plate material is C _emin , the set value of each actuator is calculated, and the plate crown C _qmin in the quarter portion at that time is calculated. 3. When the target value of the plate crown near the width end of the plate material is C _emax , the set value of each actuator is calculated, and the plate crown C _qmax in the quarter part at that time is calculated. 4. The target value C _q of the plate crown in the quarter part is
When C _qmin ≦ C _q ≦ C _qmax is satisfied, the target value C _e of the plate crown in the vicinity of the width end of the plate is set to C _e = C
_emin + (C _emin −C _emax ) ・ (C _q −C _qmin ) / (C _qmin
-C _qmax ) and set value of each actuator is calculated. 5. The target value C _q of the plate crown in the quarter part is
When C _q ≤ C _qmin , C _e = C _emin , and C
_{When q} ≧ C _qmax , C _e = C _emax is set and the set value of each actuator is calculated.