KR890004775B1 - Shape controlling device in continuous rolling mill - Google Patents

Abstract

The shape of the material rolled in a rolling mill is controlled by a thickness reduction controller and a roll force transducer in each roll stand. Two or more consecutive roll stands including the last one, are chosen for the final shape control. The correction for the thickness reduction of these roll stands are determined as a function of the deviation of the shape provided the thickness at the run-out from the last roll stand is not changed.

Description

Shape control device of continuous rolling mill

1 shows a shape control body in a continuous rolling mill showing an embodiment of the present invention.

* Explanation of symbols for the main parts of the drawings

1: Rolling material (2a), (2b), (2c): Pushing position control device

(3a), (3b), (3c): upper rolling rolls (4a), (4b), (4c): lower rolling rolls

(5a), (5b), (5c): Rolling reaction force measurement window 6: Plate thickness detector

7: shape detection device 8: shape control device

The present invention relates to a technique for modifying the shape by changing the degree of pressing the thickness of the plate in each stand of the continuous mill, in particular in the plate shape and intermediate stand in the final stand without compromising the precision of the plate thickness of the rolled material The shape control apparatus of the continuous rolling mill which has a function of correct | amending the plate shape of within a short time.

As such a shape control method of the related art, as described in, for example, Japanese Patent Laid-Open No. 54-5384, the pressing position of a stand other than the final stand is changed in accordance with a signal from the shape detecting device, and the portion thereof is changed. The thickness of the board was changed, and the thickness of the board was controlled by modifying the push position of the final stand with respect to the variation in the plate thickness value of the resulting product. However, in the above method, there is a time delay according to the distance between the final stand and the outer one thickness and the speed of the outer plate, so that there is a thickness volume portion of the plate on the product, The shape defect occurred and it was a big obstacle in the stability of the passage of the plate during rolling operation.

SUMMARY OF THE INVENTION An object of the present invention has been made in view of the above drawbacks, and it is to provide a shape control apparatus for a continuous rolling mill capable of controlling an arbitrary short shape only without affecting the control function of the thickness of the plate.

According to the output of the outer plate shape detection device provided on the downstream side of the outer stand, which is the object of the present invention described above, the number of stages is determined so that the correction of the pressure is sequentially performed so that the plate shape defects at all stands are within the allowable range. The push position correction required for the correction is operated to execute the push position correction of the next stand at the timing when the position on the board which performs the push position correction of the most stand correcting the press position reaches the next stand, and the press on the downstream side sequentially. By performing the position correction correction according to the material traveling speed and the distance between the stands, the shape control is achieved while keeping the thickness of the plate completely constant.

Next, an embodiment of the present invention will be described with reference to the drawings.

1 shows only three stands at the most downstream side of the continuous mill for convenience of explanation. In the drawing, (1) is a rolled material, each stand (A) having upper rolling rolls (3a), (3b), and (3c) and lower rolling rolls (4a), (4b), and (4c), (B) and (C) include the push position control devices 2a, 2b, and 2c, wherein the plate thickness detection device 6 and the shape detection device 7 are provided downstream of the outer stand. It is installed. 5a, 5b, and 5c are rolling force detection devices, and 8 are shape control devices.

_c로 하고 (B) 및 (C)스탠드 에서의 압연반력값 P_b및 P_c를 다음의 계산으로 변경한다.Here, it is assumed that the thickness of the outer plate coincides with the target value by the thickness control function of the plate of the device (not shown). At this time, if any shape defect is recognized by the shape detector 7, the value is

with _c and change the (B) and (C) rolling reaction force value in the stand P _b and P _c by the following calculation.

here,

H _a , h _b and h _c are the thickness of each outer plate at each stand (A), (B) and (C), and q _a , q _b and q _c and each stand (A), It is each baking coefficient in (B) and (C).

In addition, when i is any stand number one ε _i is the shape (flatness), the display, and the ε _i by the ratio c ₁ / h ₁ and the plastic flow coefficient ξ _i of the thickness of the crown plate in each stand, For example, as described in the "Summary of the Lectures on the 106th Lecture of the Steel Association of Japan (II), page 69, September 1983, Japan Steel Association", expressed in the following formula (3). do.

In addition, the plate crown is Ci amount influence coefficient of the influence coefficients γ ₁ of the impact coefficient α _1, the input side plate crown effect on the coefficient C _1- 1 β _1, roll bending pressure F ₁ for the rolling force Pi at each stand It is represented by the following (4) Formula by (gamma) ₁ .

In addition, the relationship between the thickness h ₁ of the outer plate and the rolling reaction force P ₁ is as follows.

In the above (3), (4) and (5), the parts corresponding to the stands (B) and (C) are as shown in the following (6) time.

ε_c에 대해서도, (1)식을 (6)식에 대입하면,For this reason, when performing push position correction (rolling reaction value is corrected) in the stand B and (C) determined according to said Formula (1), arbitrary shape defect state

Also for ε _c , substituting equation (1) into equation (6),

In this equation (7), the thickness of the final stand outer plate does not change before and after the shape correction operation.

In addition, the rolling reaction value correction at each stand is easily realized by the following push position correction.

When the constant value of the bottom spring of each stand is set to mi, the above-described rolling reaction value correction (ΔP _b , ΔP _c ) is calculated according to the following formulas (8) and (9). This is possible.

First, the pressing position correction Δsb on the stand B is executed by the pressing position control device 2b, and the pressing position correction of the stand C is pressed at the timing when the position on the plate reaches the stand C. It will be performed by the position control device 2C, in which the thickness of the outer plate is constant for all parts, and only the plate shape is subjected to arbitrary modifications.

By the press position correction and the rolling load correction in the stands B and C, the shape in the stand B changes as shown in the following expression (10). By the formula (3), (4),

When the numerical value exceeds the allowable range or a plate shape defect is already observed in this part, the following rolling force change is necessary in the stands A and B.

As described above, the thickness of the stand B is not changed by the change of the rolling force according to the above (11) and (12) equations, and only the shape defect b1 is corrected.

The shape in the stand C is subject to the same change as the following (13) due to this rolling force change ΔP _a ² , ΔP _b ² ｝.

This iteration is an exponentially very fast decay process that can be done in a very small number of times.

Therefore, the actually required rolling force change amount in each stand is calculated | required by following (15) Formula.

After changing the pushing position change amount △ sa, △ sb, △ sc, measure the timing according to the plate running speed, and adjust the pressing position of stand (A), (B), (C) in that order. The shape defects in the stand B and the stand C are corrected in a very short time without changing the thickness of all the boards. Therefore, it is possible to suppress the defective portion at the shortest distance without generating the defective thickness portion of the plate on the outer plate.

In the above embodiment, the correction of the shape defect during the rolling of one rolling material in the rolling of the same material was explained. However, in accordance with the above principle, the actual thickness value of the rolling is sequentially rolled to the next material. The results can be used even after the next material.

As described above, according to the present invention, only the rolled plate shape can be controlled within a short time without any influence on the thickness control function of the plate.

Claims (1)

In a continuous rolling mill consisting of a plurality of stands (A, B, C) having a pressing position control device (2a, 2b, 2c) and rolling reaction force detection devices (5a, 5b, 5c), the outer end of the final stand (C). According to the plate shape detection result of the shape detection apparatus 7 provided, the amount of press position correction | amendment in two or more stands of the said continuous rolling mill is decided, and a press position correction is performed according to the timing which the same point of a rolling material passes through the said stand. The shape control apparatus of the continuous rolling mill, characterized in that to control the plate shape in the final stand and the intermediate stand to a predetermined range by maintaining a constant thickness of the final stand outer plate.

Images