JPS6261710A - Detection of meandering of steel strip - Google Patents

Abstract

PURPOSE:To preliminary detect the meandering of a steel strip and to prevent the meandering by detecting the tension distribution in the transverse direction of the strip, calculating the difference between the right and left moments with regard to the center of the strip width and detecting the meandering from the difference in the moments. CONSTITUTION:The product of the tension up to the center in the transverse direction of the steel strip 1 with regard to the central axis 2 thereof, i.e., moment is calculated and the calculation is executed respectively on the left side and right side of the central axis 2. The quantity and direction of the meandering are estimated from the difference in the moments between the right and the left. The generation of the meandering of the steel strip to be passed in a long surface treatment installation in which the meandering is liable to arise is thereby detected.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for detecting meandering of a steel strip in a continuous processing facility for steel strips.

(Conventional technology) Continuous processing equipment in the cold rolling sector of the steel industry includes equipment for pickling, cold rolling, continuous annealing, continuous plating, etc. During operation, if the line is stopped midway through, quality problems may occur. Therefore, a steel strip storage device is installed, and the coil receiver is structured so that continuous surface treatment of the steel strip can be performed even if the line is stopped at the inlet and outlet sides of the equipment during unloading. In these facilities, the length of the lines has increased, causing problems such as meandering.

Basically, the causes of meandering can be divided into those caused by the equipment and those caused by the original plate. Equipment-related causes include roll alignment errors (levelness, parallelism).
Possible causes include wear on one side of the roll, and roll pressure on one side of the roll. These occurrences can be completely eliminated by adjusting or repairing the equipment. -10,000, The cause of meandering due to the original plate is poor flatness of the steel plate (medium elongation, edge elongation).

This problem of poor steel strip shape cannot be completely eliminated at the current level of rolling technology. Therefore, in continuous processing equipment, meandering correction devices are used to correct meandering to some extent.

Current meandering prevention technology, for example,
As stated in Japanese Patent No. 31, meandering can be prevented by varying the crown of the no-roll.

Other known meandering prevention techniques include a method in which the position of the steel strip is directly detected using a steel strip position detector, and a meandering correction roll is applied to correct the meandering. Therefore, at the installation location a where the roll span is long and the roll span is likely to meander, measures such as newly installing a meandering correction tcd at that location are taken.

(Problem to be solved by the invention) In a continuous annealing furnace, etc., it is difficult to install a band position detector, and in the past, the position of the steel strip was detected with a television camera, etc., and the meandering correction roll was manually moved to correct the meandering. It was also against. Some steel strips enter the furnace and meander rapidly, and manual correction is not enough to correct such rapid meandering, which often results in rough edges or cracks. 'r and other troubles. Therefore, the object of the present invention is to detect the meandering of the 3i4 scale in advance and to prevent the meandering.

(Another means to solve the problem) The meandering caused by the original plate is related to the non-uniformity of its tension distribution. Therefore, the present invention uses a steel strip tension distribution detector to measure the tension distribution in the width direction of the steel strip, calculates the degree of unevenness of the tension distribution (moment) Th with respect to the central axis of the steel strip in the width direction, and
The magnitude of the meandering is determined according to the left and right balance of moments with respect to the central axis, and meandering is detected based on the difference in moments.

Here, the tension distribution detector may be of any type as long as it can detect the tension distribution in the width direction of the steel strip.For example, a strain gauge or piezoelectric element may be installed inside the roll to detect the force with which the surface of the roll is pushed. Examples include things to do.

(Function) The present invention will be explained with reference to FIGS. 1a and 1b and FIG. 2.

FIGS. 1(a) and 1(b) illustrate the relationship between uneven tension distribution in a steel strip and meandering. The meandering influence of non-uniform tension distribution can be divided into the following two cases. 1
One is due to the camber shown in FIG. 1 (al).

In a rolling mill, the winding tension is high, and small camber becomes latent due to the influence of the tension.

At this time, the tension distribution becomes uneven because the bent object is straightened. When this comes to equipment with low tension, camber becomes obvious and causes meandering. Therefore, if the In of the non-uniform tension distribution is known, the size of the camber can be estimated, and the magnitude of the meandering can be determined.

The other case is when a local shape defect such as an elongated edge occurs as shown in FIG. 1(b). The tension in the part where the defective shape is obvious is O. Therefore, when the steel strip is rolled around the rolls in this condition, the frictional force between the rolls and the steel strip acts unevenly in the strip width direction, causing a moment to act on the steel strip, which changes the incident angle of the steel strip with respect to the rolls, causing meandering. occurs.

Furthermore, since the throttle in the continuous annealing furnace has a crown, the centering action of the crown may move as a disturbance, causing rapid meandering.

In all of the above cases, meandering occurs due to uneven tension distribution in the steel strip. Therefore, for example, meandering can be estimated by calculating the moment imbalance with respect to the center of the tension distribution in the plate width direction.

The calculation method is calculated using the following formula based on the tension on the work side and drive side of the steel strip shown in Fig. 2.

M, -(axW1+bxW2+...)-(axD1+
bxD2+-・-)Wl, W2: Work side tension (
Sensor output) DI, D2 Ni drive side tension (sensor output) a, b: Distance from the widthwise center of the steel strip to the sensor Mo Balance of moment with respect to the center of the second plate (
Example) As shown in Fig. 2, the product of the tension and the center, that is, the moment tra, is calculated with respect to the central axis 2 in the width direction of the steel strip 1, and this is performed on the left and right sides of the central axis, respectively. The amount of meandering and the direction of meandering can be estimated based on the difference in moment with the left side. Passé: In other words, the present invention uses a tension distribution detector to detect the tension distribution in the width direction of the plate, calculates the lateral unbalance of the moment of tension with respect to the center of the plate width, and detects the magnitude of meandering. be.

(Effects of the Invention) The present invention makes it possible to detect the occurrence of meandering in a steel strip that is threaded in a long surface treatment facility where meandering is likely to occur. In particular, in a continuous annealing furnace, information on meandering can be obtained before the sheet passes through the furnace, so it is possible to suppress meandering and eliminate troubles caused by meandering by adjusting the tension in the furnace and line speed.

[Brief explanation of the drawing]

FIGS. 1(a) and 1(b) are explanatory diagrams showing the relationship between uneven tension distribution of a steel strip and meandering, and FIG. 2 is an explanatory diagram showing a method for evaluating uneven tension distribution. 1 is the steel strip, 2 is the central shaft. Patent applicant Nippon Steel Corporation Y/Nagi ((2-) λ/m(I)

Claims (1)

[Claims] A steel characterized by detecting the tension distribution in the width direction of the steel strip in continuous steel strip processing equipment, calculating the moment difference between left and right sides with respect to the center of the strip width based on the tension distribution, and detecting meandering based on the moment difference. Band meandering detection method.