JPH0822444B2 - Squeezing prevention device for hot finish rolling mill - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device capable of advantageously preventing narrowing due to meandering occurring in a rolled material passing through a hot finish rolling mill.

[0002]

2. Description of the Related Art On the inlet side of a hot finish rolling mill, meandering is usually large because no tension is applied to the trailing edge of the rolled material. Is also the same. The meandering thus generated sometimes causes double biting of the rolled material with respect to the rolling mill. That is, the side surface of the rolled material comes into strong contact with the side guides and buckles when the plate thickness is thin.
The sheets are overlapped and bitten by the rolls, causing a so-called squeezing phenomenon, which causes damage to the rolls.

As a method of preventing such a narrowing phenomenon, a meandering control by a load difference method disclosed in Japanese Patent Publication No. 59-16527 and a sensor method disclosed in Japanese Patent Publication No. 51-17465 is known. There is. Further, in JP-A-60-83704, when the front and rear end portions of the rolled material are asymmetrical in plan view, the meandering control is canceled and a control to give a convex plate crown to the rolled material is performed. It is disclosed to suppress meandering and prevent narrowing. In addition, Japanese Examined Japanese Patent Sho 59-16528
In the gazette, the force applied to the side guide between the stands of the rolling mill is measured on each of the operating side and the driving side, the in-plane bending moment of the rolled material is determined, and when this bending moment exceeds a certain limit. A method for controlling meandering by performing one-sided rolling control is disclosed.

[0004]

The meandering control based on the load difference method or the sensor method described above cannot accurately detect the meandering amount when the front and rear end portions of the rolled material are asymmetrical in plan view. Also, the method of giving a convex plate crown when the planar shape of the front and rear end portions of the rolled material is asymmetrical,
The planar shape cannot be recognized in a short time, and it is difficult to prevent narrowing down. Further, in the method of obtaining the in-plane bending moment of the rolled material, the contact position between the rolled material and the guide cannot be specified, so the limit of buckling occurrence of the rolled material cannot be easily known, and it is difficult to prevent narrowing. is there. Therefore, an object of the present invention is to provide a device that can easily prevent narrowing.

[0005]

According to the present invention, a vertical roller is provided on each of a pair of side guides disposed on the entry side of a stand of a hot finish rolling mill and on the operating side and drive side of the stand, and each vertical guide is provided. It is equipped with a measuring device that measures the force applied to the roller when passing the rolled material and an arithmetic controller that controls the release of the rolling of the latter stand when the measured value of at least one vertical roller exceeds a predetermined value. This is a narrowing prevention device for the hot finish rolling mill.

Further, it is advantageous in practice that the measuring instrument is equipped with a strain gauge on the rotary shaft of the vertical roller.

[0007]

Next, the reason why the narrowing can be prevented by measuring the force applied to the side guide when the rolled material exiting each stand of the rolling mill is passed will be described in detail. As shown in FIG. 1, when the meandering rolled material 2 is forcibly suppressed by the side guide 3 on the entrance side of the stand 1 of the hot finish rolling mill, the rolled material 2 is constrained by the vertical roller 4 of the side guide 3 by the binding force P. Receive. This restraining force P can be measured by, for example, a strain gauge attached to the vertical roller 4.

On the other hand, the maximum load that does not cause buckling of the rolled material 2, that is, the buckling occurrence limit load Pk, which is an index of narrowing, is given by the following equation (1).

[0009]

[Formula 1] Pk = K · π ² · E · h ₁ ³ / {12 (1-ν ² ) b} ------ (1) where E: Young's modulus ν: Poisson's ratio h ₁ : Inlet plate Thickness b: Board width L: Distance between roll center of stand and vertical roller

In the above equation (1), K is a function of the plate width b and the distance L, and can be obtained from FIG. 2, for example. Furthermore, in a rolling mill having vertical rollers incorporated in the side guides as shown in FIG. 1, since there is only one point of contact between the rolled material and the side guides, L in equation (1) is given by a constant, The value of K can be easily obtained by the plate width b.

Therefore, in the apparatus of the present invention, the load on the vertical roller, that is, the restraining force P is measured and compared with the above-mentioned buckling occurrence limit load Pk. That is, since narrowing occurs when P> Pk, it is possible to predict narrowing by actually measuring P and comparing it with Pk.

For example, as shown in FIG. 3 based on the measured data of P, it was found that P> Pk was satisfied at time A at the time of trailing edge of the rolled material. Therefore, at this time, the control for releasing the reduction in the rear stand is performed. Should be done. Although this is applicable to all rolling mills, it is suitable for rolling mills with a hydraulic reduction control system.

[0013]

FIG. 4 shows a narrowing device according to the present invention. That is, the operating side of the rolling mill stand 1 shown in FIG.
Loads P _OP and P _DR applied to the vertical rollers on the operating side and the driving side of each stand are measured with the strain gauges 5a and 5b connected to the vertical rollers 3 of the side guides of the OP and the driving side DR, and then each The measured value is sent via amplifiers 6a and 6b.
It is input to the diagnosis CPU 7, and here, P _OP and P _DR are compared with the buckling occurrence limit load Pk that has been input in advance for each rolled material. And P _OP > αPk and / or P _DR > αPk
At this time, the diagnosis CPU 7 outputs a command to release the pressure reduction to the hydraulic pressure reduction control panel 8 of the rear stand. Where α is
This is a safety factor to allow for errors due to differences in the steel type of the rolled material, plate width, plate thickness, or the rigidity of the rolling mill.

Further, as shown in FIG. 5, the strain gauge 5a (5b) was attached by being attached to the central shaft 9 of the vertical roller 4 and converted by the following equation (2) to obtain the load P. This makes it possible to measure the load applied to the vertical roller, which is a rotating body.

[0015]

[Equation 2] P = (2 · E · Z / a) · ε (2) where E: Young's modulus of the central axis Z: Sectional modulus of the strain gauge pasted part ε: Measured strain value

Although the apparatus according to the present invention releases the subsequent reduction based on the actual measurement of the load P, it performs meandering by performing subsequent lateral reduction load control of the rolling mill based on the actual measurement of the load P. It can also be used as a device for controlling.

[0017]

According to the present invention, the occurrence of narrowing can be predicted and prevented from occurring, so that the suspension of rolling due to the narrowing can be avoided, which greatly contributes to the stabilization of hot rolling.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a passing state of a rolling mill.

FIG. 2 is a graph for obtaining a constant K.

FIG. 3 is a graph showing measured data of load P.

FIG. 4 is a schematic view showing the device of the present invention.

FIG. 5 is a schematic diagram showing the mounting of a strain gauge.

[Explanation of symbols]

 1 Stand 2 Rolled material 3 Side guide 4 Vertical roller 5a Strain gauge 5b Strain gauge 6a Amplifier 6b Amplifier 7 Diagnostic CPU 8 Hydraulic reduction control panel

Claims (2)

[Claims] 1. A vertical roller is provided on each of a pair of side guides arranged on the operating side and the driving side of the stand of the hot finish rolling mill at the entrance side, and the force applied when each vertical roller passes through the rolled material. Of a hot finish rolling mill comprising a measuring device for measuring the temperature and a calculation controller for controlling the release of the reduction of the rear stand when the measured value of at least one of the vertical rollers exceeds a predetermined value. Squeezing prevention device. 2. The device according to claim 1, wherein the measuring device is equipped with a strain gauge on the rotary shaft of the vertical roller.