JPH0822445B2 - Method of detecting the degree of meandering of a stand in a hot finishing 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 stand of a rolling mill, which is capable of knowing which stand of the rolling mill causes the meandering occurring in a rolled material passing through a hot finish rolling mill. Regarding detection method.

[0002]

2. Description of the Related Art On the entry side of hot finish rolling, 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 when the plate thickness is thin, it buckles and becomes an overlap of two sheets, and is caught in the roll, causing a so-called squeezing phenomenon and causing damage to the roll.

As a method for preventing such meandering and further narrowing-down phenomenon, meandering control by a load difference method disclosed in Japanese Patent Publication No. 59-16527 and a sensor method disclosed in Japanese Patent Laid-Open No. 51-17465. It has been known. In addition, JP 60
In JP-83704A, when the front and rear end portions of the rolled material are asymmetrical in plan view, the meandering control is released and the rolled material is controlled to have a convex plate crown, thereby preventing the narrowing. It is disclosed. Furthermore, Japanese Examined Japanese Patent Sho
In the −16528 publication, the force applied to the side guides between the stands of the rolling mill is measured, the in-plane bending moment of the rolled material is determined, and when this bending moment exceeds a certain limit, one-sided rolling control is performed to meander. A method of controlling the is disclosed.

[0004]

The above-mentioned methods detect various tendencies of meandering caused mainly by a rolled material in a stand of a rolling mill, and apply this to a meandering control system by rolling the same rolled material. However, since it is not possible to know the degree to which each stand induces and promotes meandering, that is, the degree of influence on meandering, in other words, control to suppress the occurrence of meandering is most effective. It is difficult to perform efficient meandering control because it is not possible to specify a specific stand. Therefore, an object of the present invention is to propose a detection method capable of knowing the degree of influence of meandering in each stand of a rolling mill.

[0005]

According to the present invention, a force applied to a side guide provided on an entrance side of each stand of a hot finish rolling mill when a rolled material is passed is measured for each stand, and based on the measured value. By comparing the meandering influence coefficient calculated in each stand between each stand, and specifying the magnitude of the influence on the meandering of the rolled material in each stand, a method of detecting the meandering influence degree of the stand in the hot finish rolling mill. is there.

[0006] Here, it is advantageous to measure the force applied to the side guide by a vertical roller provided inside the side guide for guiding the rolled material.

[0007]

Next, it will be described in detail that the stand having the greatest influence of the meandering can be specified by measuring the force applied to the side guide when the rolled material exiting each stand of the rolling mill passes. 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 binding force P by the vertical roller 4 installed on the side guide 3 is , Given by the following equation (1).

[0008]

[Equation 1] P = (h ₁ · b ² · σ ₀ ) / 6L ------ (1) where h _{1 is the} plate thickness on the input side b is the plate width L is the distance between the roll center of the stand and the vertical roller σ ₀ : constant

In the above equation (1), the constant σ ₀ is determined by the reduction ratio and the change in the wedge ratio. Further, in the actual finishing mill, the strip width b and the distance L are the same constant at any stand. Shall be given as.

The load P _n (n is the stand number) detected by the vertical rollers of the side guides on the entrance side of each stand.
Is

[Formula 2] P _n = (h _n · b ² · σ _n ) / 6L ------ (2) where h _n : thickness of the n-stand stand-in side plate σ _n : a constant at the n-stand. 2) From

[0011]

## EQU3 ## σ _n = α (P _n / h _n ) ------ (3) However, α = 6 L / b ² can be obtained.

This constant σ _n is σ ₀ in n stands.
Is a value determined by the rolling reduction of the n-stand and the change of the wedge ratio. Here, the wedge ratio change is a numerical value that is generally used as an index for quantitatively handling the amount of meandering, and one that controls the wedge ratio change is the rolling mill factor (difference in mill rigidity, The difference between the left and right levels), and the other factor is the base material factor (such as the entry side wedge). Here, the base material factor is created by the meandering factor up to the (n−1) th stand. Therefore, in order to obtain the meandering effect degree at the stand, σ
It is necessary to subtract the degree of influence due to the base material factor from _n. The constant at each stand is obtained from the following equation (4), and this is defined as the meandering influence degree A _n at each stand.

[0013]

The Equation 4] _{A n = σ n -σ n-} 1 ------ (4) The meandering influence A _n by comparing at each stand, identify the stand that the most impact on the meandering can do.

[0014]

EXAMPLES The detection system shown in FIG. 2 was used to evaluate the degree of meandering influence in each stand of the hot finish rolling mill. That is, with the strain gauges 5a and 5b mounted on the vertical rollers 4 of the side guides on the operating and driving sides of each stand, the load P applied to the vertical rollers on the operating and driving sides of each stand is set.
_nOP and P _nDR are measured respectively, and then the respective measured values are input to the diagnostic CPU 7 via the amplifiers 6a and 6b, where the load P _n applied to the vertical roller on the stand-in side of each stand is calculated from the following equation (5). Then, the constant σ _n at each stand is calculated from the above equation (3).

[0015]

Equation 5] _{P n = P nOP -P nDR ------} (5) where P _nOP: n side guide force measurements at stand operating side P _NDR: side guides force measurements at n stand drive side

The meandering influence degree A _n at each stand is obtained using the constant σ _n at each stand obtained through the above measurement and calculation and the above equation (4), and the meandering influence degree A _n is obtained.
_By comparing _n between each stand, the stand having the largest influence on the meandering is identified. In the figure, 8 is a monitor.

Then, with respect to the stand specified as described above according to the present invention, the leveling correction and the reduction ratio are adjusted, and the operation is performed while suppressing the meandering.
The suspension rate of operation due to the narrowing of rolled material was 0.2%. As a comparison, when the same hot finish rolling was performed on the same rolled material without the above-mentioned meandering control, the suspension rate of the operation due to the narrowing of the rolled material was 3.3%. The rest rate was defined as the ratio of the rest time by narrowing down to the total operation time excluding the planned rest time.

[0018]

According to the present invention, it is possible to identify the stand that has the greatest influence on the meandering. Therefore, the leveling correction for suppressing the meandering and the adjustment of the rolling reduction can be performed for the most effective stand. Can be carried out as a result, and contributes greatly to stabilization of hot rolling.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing the outline of the method of the present invention.

FIG. 2 is a schematic diagram showing a detection system used in the present invention.

[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

Claims (1)

[Claims] 1. A force applied to a side guide provided on the entrance side of each stand of a hot finish rolling mill when passing a rolled material is measured for each stand, and a meandering influence coefficient calculated based on the measured value is calculated. A method of detecting the degree of meandering of a stand in a hot finish rolling mill, which comprises comparing the stands and specifying the magnitude of the influence on the meandering of the rolled material at each stand.