JPH01321007A - Rolling method including edge drop control means for sheet stock - Google Patents

Abstract

PURPOSE:To control edge drops in a required target range in spite of increase of rolling amounts by correcting a shift amount of optimum frustum shape work rolls by considering the taper part wear presumed from a rolled length after roll changing. CONSTITUTION:As for setting a shift amount of frustum shape work rolls 12, 14 in a rolling mill 10, a shift amount WSdelta1 of the rolls 12, 14 is calculated by a host computer 20 based on rolling information including rolling conditions, pass schedule, roll conditions, and a thickness deviation target value in the width direction. In that time, if the shift amount WSdelta1 is used as it is, roll wear increases as a rolling length (l) increases and a deviation of a taper starting point at which the rolls 12, 14 being in contact with a rolled sheet stock 8 from a sheet thickness target value in the sheet width direction is generated. Thus, the shift calculation amount WSdelta1 is corrected by a value according with a shifting amount of the taper starting point to return the starting point to the initial position.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a method for rolling a plate material including an edge drop control means, and in particular to a method for rolling a plate material, which is suitable for use in a continuous cold rolling mill for steel plates, and is suitable for use in a continuous cold rolling mill for steel plates. In order to improve the thickness deviation in the width direction,
The present invention relates to an improvement in a method of rolling a plate using a rolling mill in which a trapezoidal work roll having a tapered end portion as an edge drop control means is shiftable at least in the width direction of the plate.

[Conventional technology]

BACKGROUND ART Conventionally, equipment and methods for performing work roll bending and work roll shifting in order to improve the thickness deviation in the width direction of a steel plate are known from, for example, JP-A-59-133903 and JP-A-60-12213. According to the above-mentioned Japanese Patent Application Laid-Open No. 59-133903, the control amount for controlling the thickness deviation in the width direction of the sheet is two: the shift amount by shifting the work roll, and the bending amount by roll bending. ing. Also, according to JP-A-60-12213, the above-mentioned JP-A-59
Similar to the method described in 133903, the work roll shift amount and roll bending amount are controlled, and the measured value of the edge drop amount of the steel plate from the plate thickness gauge at the exit side of the final stand and the target edge drop value of the steel plate. are compared and calculated, and based on this comparison calculation value, the shift control of the trapezoidal work roll in the board width direction and the operation pressure control of the roll bender are performed. The above two methods are particularly effective for edge drop countermeasures, but in the former case, the thickness deviation in the width direction is greatly affected by the roll rolling load, so controlling only the shift amount and bender pressure will not be enough. There was a problem that the control effect was poor. On the other hand, the latter also has a problem in its control amount, and in any case, after cold rolling, it is difficult to avoid the tendency for the thickness of the rolled material to suddenly become thinner near the end of the rolled material. In this way, when there is a thickness deviation in the width direction of a cold rolled steel plate, it not only reduces the yield due to cutting off defective parts such as edge drops, but also hinders the automation of the processing process at the place where the steel plate is used. This method had the disadvantage of causing problems. In order to solve these problems, the applicant has already proposed in Japanese Patent Application Laid-Open No. 179804/1982, the rolling material conditions, pass schedule, roll conditions, and plate Using the target thickness deviation in the width direction,
This paper proposes a method to find the optimal work roll shift position that satisfies the target value. According to this method, the roll conditions are determined by the initial roll conditions.

[Problems to be solved by the invention]

However, the method proposed in JP-A-62-179804 is effective as a countermeasure against edge drop, which is described as an example of controlling the thickness distribution in the width direction of a steel plate, when the initial roll conditions do not change. However, the initial roll conditions had a problem in that as the rolling length became longer, the roll crown changed depending on the wear condition. That is, depending on the method proposed in JP-A No. 62-179804, as the amount of rolling increases, the thickness of the material to be rolled tends to decrease rapidly near the end of the material after cold rolling. On the other hand, Japanese Patent Application Laid-Open No. 60-240319 discloses that the shape of the rolled material is adjusted to the optimal sheet crown and edge drop regardless of the increase or decrease in roll flattening due to fluctuations in rolling force during rolling.
A rolling mill is disclosed, which is also disclosed in Japanese Unexamined Patent Application Publication No. 6
Similar to 2-179804, when the initial roll shape is worn out by rolling. There was a problem in that it could not be reflected when setting the shift position.

[Purpose of the invention]

The present invention has been made to solve the above-mentioned conventional problem 181, and provides an edge drop ilJ WJ means that can bring the edge drop within a desired target range regardless of the increase in rolling amount. An object of the present invention is to provide a method for rolling a plate material including the following.

[Means to solve the problem]

The present invention provides rolling material conditions, pass schedules, and roll conditions when rolling a plate using a rolling mill in which a trapezoidal work roll with a tapered roll end can be shifted at least in the width direction of the plate. In addition, the shift amount of the trapezoidal work roll is calculated based on the target thickness deviation in the width direction of the plate,
From the rolling length of the trapezoidal work roll after the roll change,
The above objective is achieved by estimating the amount of movement of the taper start point where the trapezoidal work roll contacts the plate material, correcting the calculated shift amount based on the estimated amount of movement, and setting the shift position of the trapezoidal work roll. It is something.

[Effect]

In the conventional sheet rolling method that performs edge drop control, the present invention provides an optimal trapezoidal work roll shift calculated based on the pass schedule, rolled material conditions, roll conditions, and the S value of the thickness distribution in the sheet width direction. The amount is further corrected by taking into consideration the wear of the tapered part estimated from the length rolled so far after the roll change of the trapezoidal work roll. Therefore, the edge drop can be controlled within a desired target range, regardless of changes in roll conditions from the initial conditions due to an increase in rolling amount.

【Example】

Embodiments of the present invention will be described in detail below with reference to the drawings. As shown in FIG. 1, for example, a first stand rolling mill 10 of a continuous rolling mill to which the present invention is applied includes upper and lower trapezoidal (tapered) work rolls 12 with tapered roll ends.
14, and the trapezoidal work rolls 12.14 can be shifted in the sheet width direction by, for example, a pair of hydraulic cylinders 16, and can be bent by a pair of roll benders 18. When setting the shift positions of the trapezoidal work rolls 12 and 14 of this rolling mill 110, first, in the host computer (process computer P/C) 20, for example, by the method disclosed by the applicant in Japanese Patent Application Laid-open No. 179804/1983, The shift amount WSδ1 of the trapezoidal work roll is calculated based on rolling information such as the rolled material conditions, pass schedule, roll conditions, and target thickness deviation in the width direction. On this occasion,
If the trapezoidal work roll shift amount calculation value WS6+ is used as is, roll wear progresses as the rolling length β increases, and as shown in FIG. It is not possible to prevent the taper start point that comes into contact with a certain plate material 8 from shifting from the target value of plate thickness deviation in the plate width direction due to movement from point A to point B. Therefore, in the present invention, the calculated shift amount WSδI of the trapezoidal work roll (12) is moved from the taper start point A to point B! The taper start point is returned from point B to point A by correcting the value according to IC. Specifically, according to the inventor's research, the rolling length that has been rolled so far from the initial state of the crown after changing the rolls,
The relationship between the amount of movement C of the taper starting point was as shown in FIG. According to the figure, approximately 0 per rolling length 1G, 0001
．． It can be seen that the starting point of the 8n server moves. Therefore,
For example, when rolling 60,000 ml, the taper starting point moves by about 5 mm, which is understood to have a large influence on control. Therefore, in the present invention, when setting the shift position of the trapezoidal work roll in the process computer 2o,
The trapezoidal work roll shift amount calculated value WSδ1 is corrected, for example, using the following equation. WSδ-WS5++0,8xi...(1) Here,
WSδ is the set position of the trapezoidal work roll, and a is the rolling length (in units of 10,000 liters) that has been rolled since the trapezoidal work roll was changed. In this way, the shift position WSδ determined by the process computer 20 and the set value of the bender pressure determined by a known method are controlled by the direct digital controller (D
DC) 22, and the hydraulic cylinder 16 and roll bender 18 are operated. The direct digital control device 22 also collects data on actual loads and bender pressures and outputs them to the process computer 2o. Figure 4 shows the rolling length β and edge drop when the present invention is applied to the first stand of a cold continuous rolling mill consisting of three rolling stands (-dashed line) and when it is not applied (solid line). It shows the relationship between deviations (deviations in plate thickness at points 5On and 10+n from the edge of the plate). As is clear from FIG. 4, it can be seen that the controllability of the present invention is improved compared to the conventional method. In addition, although in the said Example, this invention was applied to the cold rolling of a steel plate, the scope of application of this invention is not limited to this.

【Effect of the invention】

As explained above, according to the present invention, edge drop can be controlled within a desired target range regardless of an increase in rolling amount. Therefore, it has excellent effects such as preventing a decrease in yield due to cutting off defective parts such as edge drops, and also making it possible to automate the processing process at the place where the product is used.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the basic configuration of a rolling machine to which the present invention is applied, FIG. 2 is a diagram for explaining the present invention in detail, and FIG. Fig. 4 is a diagram showing an example of the relationship between rolling length and edge drop deviation to show the effect of the present invention. 8... Plate material (rolled material), 10... Rolling machine, 12.14... Trapezoidal work roll, 16... Hydraulic cylinder, 20... Process computer (P/C), WS6i
...Trapezoidal work roll shift amount calculation value, AlB...
Taper start point, C... Taper start point movement, B... Roll length, WSδ... Trapezoidal work roll shift amount setting value.

Claims (1)

[Claims] (1) When rolling a plate using a rolling mill in which a trapezoidal work roll with a tapered roll end can be shifted at least in the width direction of the plate, the conditions of the rolled material, pass schedule, roll conditions, and Calculate the shift amount of the trapezoidal work roll based on the target thickness deviation in the sheet width direction, and calculate the rolling length of the trapezoidal work roll after the roll change.
Edge drop control means for estimating the amount of movement of a taper start point where the trapezoidal work roll contacts the plate material, correcting the calculated shift amount based on the estimated amount of movement, and setting the shift position of the trapezoidal work roll. A method of rolling plate materials including