KR20030053606A - Compensation Method Of Width Margin After Replacement Of Rolling Roll - Google Patents

Abstract

PURPOSE: A method for compensating width margin after replacement of rolling roll is provided to prevent defects of width margin and realize constant width quality of strip irrespective of conditions of the rolling roll calculating opening setup of width rolling mill considering conditions of the rolling roll. CONSTITUTION: In a method for compensating width margin after replacement of rolling roll comprising the processes of calculating target width of width rolling control from rolling instruction data, calculating width rolling amount from a difference between width information of slab and target width and calculating width rolling amount per pass from the width rolling amount and load distribution per pass so that opening of width rolling mill is set up, the method further comprises the process of compensating width margin by adding width margin compensation value to the target width in case that rolling sequence count of rolling workpiece is less than critical value after calculation of the target width, wherein the width margin compensation value is obtained from actual deviation values of width margin according to rolling sequence and prediction result values of regression analysis.

Description

Compensation Method Of Width Margin After Replacement Of Rolling Roll}

The present invention relates to a width margin compensation method after rolling roll replacement, and more particularly, to a width rolling machine in consideration of a variation in width margin due to a roll crown immediately after replacement of a rough rolling roll in a hot rolling process in which a width rolling equipment (Edger) is installed. It relates to a width margin compensation method after rolling roll replacement to compensate for the margin.

The width rolling setting in the rough milling process of the general hot rolling process is to calculate the target width by a predetermined mathematical model, and then the rolling reduction and opening degree of the width rolling mill, This is done by calculating the rolling speed and the like.

That is, referring to the conventional width rolling schedule calculation method applied in the conventional hot rolling mill with reference to FIG. Calculate the target width W _{t of} .

W _t = coil width × (1 + coefficient of linear expansion × target temperature) + target width margin

Next, the difference between the width information of the slab and the target width is calculated by a mathematical model that sets the width rolling amount.

Then, the width rolling amount between each stand is calculated according to the load distribution of the rolling mill for each pass (width rolling amount for each pass = width rolling amount x load distribution for each pass), and then each opening of the width rolling machine is calculated and set (width Opening degree of the mill = width rolling width / width spreading rate per pass).

In this setting, the stretching (width spreading) occurs in the width direction due to the rolling amount appearing when rolling is performed using a horizontal rolling roll, which is calculated and applied to the expected spreading amount according to the conditions of the material.

After completing the calculation setting as described above, the operator completes the width rolling setting by adjusting the opening degree by additionally setting an arbitrary width margin value or determined by a formula.

On the other hand, the material in the hot rolling is a high temperature, especially during rough rolling, as the temperature of the material reaches 950 ℃ to 1100 ℃, thermal expansion in the part where the material contacts the rolling mill roll during rolling, which is a thermal crown ( thermal crown).

Particularly, when the rolling work is performed by replacing the rolling rolls, the thermal crown is rolled in the unformed state for about 10 initial materials, and the width spreading becomes smaller due to the smaller width direction deformation of the edge portion. .

Figure 2 is a roll profile (roll profile) of the rough rolling roll, comparing the roll profile before cooling and the roll profile after cooling after the roll replacement, it can be seen that the difference in the crown appear before and after cooling is very large.

On the other hand, the width margin value is a margin value that is arbitrarily added so that it can be rolled to a larger width at the time of rolling in order to solve this problem, since it is not generally able to exactly match the coil width required by the hot rolling operation alone. If the width required by the family is 1,000mm, if the value after rolling is 999mm, the product will be defective.To prevent this, roll the target width by adding 1,000mm to about + 1mm so that the remaining amount can be cut off so that the width can be cut off. To prevent.

However, in the conventional rolling method, in setting the opening degree of the width rolling amount, the target width is calculated and the width margin is given only in consideration of the conditions such as the dimensions and the components of the raw material, so that the crown generated in the horizontal rolling roll as described above. Due to the unpredictable change in the width direction due to the change of, the width margin hit ratio after rolling has been greatly reduced in the first 10 sheets.

In particular, the crude rolling rolls should be replaced at least once a day. At this time, the initial crowns given by the polishing machine and the thermal crowns appearing after prolonged rolling are not considered at all, and thus, between the rolled material working immediately after the roll change and the conventional rolled material The width margin hit ratio of has been very low, and thus there has been a problem that a large load on the post-processing work due to the width margin failure.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and its object is to calculate the width of the rolling mill in consideration of the conditions of the rolling rolls, so that a constant width quality of the rolling material can be achieved regardless of the conditions of the rolling rolls. The present invention provides a method of compensating for a width margin after rolling roll replacement.

1 is a flow chart showing a conventional width margin setting method,

2 is a view showing a roll profile of a conventional rough rolling roll,

3 is a graph obtained by calculating the margin margin deviation according to the rolling order to derive a width margin compensation method according to the present invention;

4 is a flowchart showing a width margin compensation method according to the present invention;

Figure 5a is a figure showing the rolling width margin performance before applying the width margin compensation method according to the present invention,

Figure 5b is a figure showing the rolling width margin results as a result of applying the width margin compensation method according to the present invention.

Width margin compensation method after rolling roll replacement according to the present invention for achieving the above object, calculates the target width of the width rolling control from the rolling instruction data, the width rolling amount from the difference between the width information of the slab and the target width Calculate the width rolling amount for each pass from the width rolling amount and the load distribution for each pass, and in setting the opening degree of the width rolling mill, after the target width calculation, when the rolling order count of the rolled material is smaller than the threshold value. The method may further include compensating for the width margin by adding the width margin compensation value to the target width.

Here, the width margin compensation value may be obtained from the width margin performance deviation value and the regression analysis prediction result value according to the rolling order.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

First, as shown in FIG. 2, the thermal profile generated during rolling was quantitatively estimated based on the large difference between the profiles before and after cooling after the replacement of the rough rolling rolls. The compensation needs were estimated and the most appropriate compensation table (see Table 1) was obtained as empirical values.

Rolling order One 2 3 4 5 6 7 8 9 10 Width margin performance deviation value (mm) -4.3 -4.0 -3.2 -3 -2.6 -2.5 -2.1 -1.6 -0.6 -0.6 Regression analysis -4.3 -3.9 -3.5 -3.1 -2.7 -2.3 -1.9 -1.4 -1.0 -0.6 Width margin compensation value (mm) -4 -4 -4 -3 -3 -2 -2 -One -One -One

In Table 1, the performance deviation is the average value of the width margin deviation performance according to the rolling order (see FIG. 3), and the regression prediction value is a prediction value derived from the following equation in which the rolling order is substituted for the width margin deviation according to the rolling order of FIG. For example, the compensation table value is the width margin compensation value determined in the order of decay, taking into account the average performance deviation and the regression prediction results.

Width margin deviation (mm) = (-4.73) + 0.411 × rolling order ⇒

inclination :

Intercept:

Looking at the width margin compensation method in consideration of the rolling roll conditions using the compensation table with reference to Figure 4, from the roll information of the rolling mill to compare the roll number (old roll number) of the material rolled immediately before the current material By determining whether the roll was replaced before the current material rolling, if the roll number and the old roll number of the current rolled material are the same, the sequence number count is increased by +1 so that the number of times the current material is rolled after the roll replacement is determined. It is possible to continuously calculate the material application, and if the rolling order count of the current rolled material is less than a threshold value, for example, 10, the compensation value is extracted from the width margin compensation value table in Table 1 to compensate for this in calculating the target width.

Accordingly, the target width value is shown in Equation 1 below.

Target Width = Coil Width × (1 + α × T) + Target Width Margin Value + (Width Margin Compensation Value) --- Equation 1

In Equation 1, α is a linear expansion coefficient and T is a rolling temperature.

5A and 5B compare the roll width margin performance, and in the figure, the horizontal axis (target width margin input value) is a target width margin value input by the rolling operator. Here, if the "target width margin input value" is 50 and the width margin value is usually 10 mm, the target margin is also decremented by ± 1 mm whenever the value to be added is added or decreased by ± 1.

Figure 5a is a result before applying the width margin compensation method according to the present invention, it can be seen that the center line is very different in the results of the rolled material and the ordinary material immediately after the roll replacement. That is, it can be seen that the width margin performance is relatively smaller than the "target width margin input value" input by the operator.

5B is a result of applying the width margin compensation method according to the present invention, showing that the performance of the rolled material immediately after the roll replacement and the width quality performance of the ordinary material are almost the same.

As described above, the width margin compensation method after the rolling roll replacement according to the present invention is calculated in consideration of the conditions of the rolling roll in setting the opening degree of the width rolling mill, thereby preventing the width margin defect regardless of the rolling roll conditions. It has the effect of realizing the constant width quality of a rolled material.

Claims (2)

The target width of the width rolling control is calculated from the rolling instruction data, the width rolling amount is calculated from the difference between the slab width information and the target width, and the width rolling amount for each pass is calculated from the width rolling amount and the load distribution for each pass. In setting the opening degree of the width rolling mill, After the target width calculation, if the rolling order count of the rolled material is less than the threshold value, the width margin compensation after the rolling roll replacement, characterized in that further comprising the step of compensating the width margin by adding a width margin compensation value to the target width Way. The method of claim 1, And the width margin compensation value is obtained from a width margin performance deviation value according to rolling order and a regression analysis prediction result value.