JPS5916528B2 - Meandering correction device for rolling mill - Google Patents

Description

[Detailed Description of the Invention] The present invention is directed to (i) enabling rolled materials such as IJ tubes to be automatically rolled straight through the center of the roll without shifting from side to side toward the operation side or drive side during rolling; This invention relates to a meandering correction device for a rolling mill.

If the rolled material shifts to the left or right (operation side or drive side) and is rolled with a bend, it becomes difficult for tandem rolling mills to insert it into the next stand or wind it onto the reel, and for reversible rolling mills. Then, there is a problem that rolling in the next pass becomes difficult.

The reason why the rolled material comes out of the rolling mill bent is that the distribution of the rolling reduction in the width direction of the rolled material is relative to the center of the width of the material.
This is due to the fact that it is not symmetrical.

Therefore, normally, workers manually adjust the opening degrees of the rolls on the left and right sides (operating side or drive side) of the rolled material while observing the bending of the rolled material on the exit side of the rolling machine. I'm trying to balance the rates.

As described above, manually correcting the meandering of the rolled material passing through the rolling mill has the disadvantage that the workability is poor and it cannot be corrected accurately.

Therefore, methods have been devised to automatically detect and correct meandering in rolled materials.

FIG. 1 shows one example of this method, in which a meandering detector 3 is provided on the exit side of the rolling mill, and the opening degree of the roll 1 is adjusted based on a signal from the meandering detector 3, thereby correcting the meandering of the rolled material 1.

In this method, it is generally difficult to install a detector in the immediate vicinity of the rolls, so there is a drawback that there is a difference between the amount of meandering at the roll gap position during actual rolling and the amount of meandering at the detection position. Ta.

Another drawback is that a time delay from the occurrence of meandering to the detection of meandering cannot be avoided.

In order to eliminate time delays, a load detector is installed at each lowering device on the operation side and drive side to detect the difference between the two and adjust the left and right roll opening degrees based on the difference to correct meandering. A method has also been devised.

However, this method has the disadvantage that the load must be detected with high precision because the load difference is very small, less than a factor of 1, compared to the detected load.

An object of the present invention is to control the left-right asymmetry of the elongation rate of the rolled material based on the bending moment that acts on the rolled material due to contact with the entrance guide of the rolling mill, so that meandering can be corrected with high precision and without time delay. The object of the present invention is to provide a meandering correction device for a rolling mill.

That is, in a rolling mill having side guides, when the rolled material starts meandering, the rolled material receives a restraining force from the side guides, and an in-plane bending moment is generated in the rolled material.

The magnitude of this in-plane bending moment differs depending on the position of the rolled material in the rolling direction, but the present invention focuses on a certain predetermined position, detects the in-plane bending moment at that position, and according to this detected value, It is designed to operate a meandering correction control system.

The present invention will be explained below with reference to the drawings.

In general rolling, the backward rate is larger than the forward rate, so instead of shaking the head as shown in Figure 1, there is a tendency to shake the tail as shown in Figure 2, and the operation of the rolled material 2 The speed difference between the side W and the drive side is noticeable on the entry side.

For example, if the rolling reduction ratio on the operating side is slightly larger than that on the driving side, the tail will swing toward the driving side.

That is, meandering can be detected more accurately on the entry side than on the exit side.

FIG. 3 shows a state in which the rolled material 2 is meandering toward the drive side and is in contact with the drive contact plate 4 of the side guide.

At this time, the rolled material receives a restraining force from the backing plate 4, and Q (
X) is subjected to in-plane pressure.

This in-plane pressure causes an in-plane bending moment to occur in the rolled material.

This in-plane bending moment varies depending on the position of the rolled material, but if the roll position A-A is adopted as the predetermined position, the in-plane bending moment MA at the roll position A-A
is expressed by the following equation.

MA=f: q(x) Therefore, there is a permissible limit moment MO.

This critical moment MO can be given in advance by work.

In the end, it is sufficient to detect the in-plane bending moment MA and operate the meandering correction control system so that IMAI≦MO (2).

MO in equation (2) corresponds to the width of a kind of dead zone.

Next, a method for detecting the in-plane bending moment MA will be explained.

Although it is difficult to measure the bending moment MA directly on the rolled material, it is possible to measure the restraining force of the side guide by measuring P and Ml in a or Pl and P2 in b, as shown in Figure 4. It is.

In the case of Figure 4a, M A = M + P 4 -----
--(3) In the case of Figure 4, MA-pH1+P212...
(4).

Of course, MA can also be determined by measuring Pl, P2...Pn as shown in FIG. 4C.

MA2, Σ Pi li...
・(5) l21 In other words, P is applied at two or more places on one side of the side guide.
It is possible to detect MA by finding .

The detection method shown in Figure 4 is the simplest.

FIG. 5 shows an embodiment of the present invention relating to a meandering detection method.

In a rolling mill having a side guide on the entry side, the backing plate 4
, 4' respectively, two load detectors 5, 6 and 5',
6' mounted through these load detectors 5, 6.5
', 6' are attached 11 and 12 away from the roll position, respectively.

If the loads in the load detectors 5 and 6 are P1tP2,
The moment MA is obtained from equation (4).

However, when there is almost no gap between the rolled material and the side guide, the rolled material comes into contact not only with the driving side backing plate 4 but also with the operating side backing plate 4', causing the load detectors 5' and 6
'The load P '1 t P '2 is also detected.

In that case, MA can be calculated using the following equation.

FIG. 6 is an embodiment of the present invention relating to a meandering correction method.

The detected values of the load detectors 5, 6, 5', and 6' are input to the calculator 7, and MA is calculated using equation (6) and output to the calculator 8.

The calculator 8 compares MQ (moment given in advance) with M, and if (1) l MA I≧MO and MA>O, tighten the drive-side reduction system (or tighten the operation-side reduction system). operate the control system 9 to open the system (2)
l MA If l≧MQ and MA <0, the elongation rate of the rolled material can be controlled by operating the control system 9' to tighten the rolling system on the operating side (or open the rolling system on the driving side). Correct asymmetry.

FIG. 7 shows the experimental results according to the present invention.

The rolling mill has a work roll diameter of 100mm and a body length of 400mm, and the rolled material is 0.8mm thick and 200mm wide.
It's a whelk.

In the figure, point ■ is the rolling start point, but in this state,
Without balancing the left and right roll opening degrees, between the opening instruction value Sw on the operating side and the opening instruction value sD on the driving side, BD-8w=
An unbalance of 15μ is provided.

As a result, meandering occurred on the drive side, and the moment MA gradually increased and settled at a certain value.

As a result of turning on the meander correction device at point [F], the set value MO
I was able to keep the MA below 9m.

Furthermore, at point [F], the meandering correction device is turned OFF, and conversely, S
When D-8w--15μ, MA showed a negative value.

This point is 0. [F], moment MA at [F],
The relationship between the bending of the rolled material obtained by rolling (difference in elongation rate Δλ between the operating side and the driving side) is shown in FIG.

It can be seen that there is a linear relationship between the moment MA and the elongation rate difference Δλ, and if the moment MA is controlled to O, the elongation rate difference Δλ=O, and rolling without bending is possible.

FIG. 9 shows an embodiment in which a load detector is incorporated into the side guide.

Load detectors 5 and 6 are incorporated between the base 10 of the side guide and the backing plate 4, and are tightened with an elastic body such as a bolt 11 that is relatively softer than the load detector and has a small spring constant. There is.

As described above, according to the present invention, the rolling system on the operation side or the drive side of the rolling mill is controlled based on the bending moment of the rolled material that acts upon contact with the entrance guide provided on the entrance side of the rolling mill. Therefore, it is possible to easily correct meandering with high precision and without time delay.

[Brief explanation of the drawing]

Figure 1 is an example of a conventional meandering correction method, Figure 2 is an illustration of the occurrence of meandering, Figure 3 is an illustration of in-plane pressure generated in the side guide, and Figure 4 is a method for detecting in-plane bending moment. Fig. 5 is a diagram showing an embodiment of the present invention, Fig. 6 is a diagram showing an embodiment of a control system to which the present invention is applied, and Fig. 7 is an experiment obtained by implementing the present invention. FIG. 8 is a diagram showing the results, and FIG. 9 is a diagram summarizing the experimental results, and FIG. 9 is an example of a method for detecting the load on the side guide. Explanation of symbols, 1...Roll, 2...Rolled material, 4゜4'...Packing plate, 5, 5', 6, 6
'... Load detector, 7.8... Arithmetic unit, 9,9'... Lowering control device.

Claims (1)

[Claims] 1. In a rolling mill, inlet guides are located on the entrance side of the rolling mill, near both ends of the width of the rolled material and along the running direction of the rolled material, and each of the two roller guides has a plurality of inlet guides. Load detectors are installed spaced apart along the running direction of the rolled material, and the detected values from each load detector provided on the double log guide as well as the values from the rolling roll position of the rolling mill to the load detector are measured. From each distance, calculate the bending moment of the rolled material due to contact with each inlet guide, and control the rolling system on the operation side or drive side of the rolling mill based on the calculated values of both bending moments. A meandering correction device for a rolling mill, characterized in that it is equipped with an arithmetic and control device that outputs a control signal to correct left-right asymmetry in the elongation rate of a material.