KR19980049983A - Plate width control method during hot thick plate rolling - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plate width control method for rolling to a target plate width during thick plate rolling. The present invention relates to an edge rolling process in an edge rolling process in which an edge roll and a horizontal roll are used to perform a breading roll. By setting the horizontal roll gap in consideration of the decrease in the slab length in the width direction and the spread amount due to the horizontal rolling, it is to provide a method for controlling the width of the plate during hot rolling, which can obtain a high plate width. There is a purpose.

According to the present invention, in the hot rolling method of steel slab subjected to the width rolling by the edge roll and the horizontal roll, the slab length variation coefficient in consideration of the amount of slab length reduction in the width direction by edge rolling and the spread amount due to the thickness rolling ( Obtaining C _L ); Using the slab length variation factor (C _L ) obtained as described above, the slab length variation amount ( Obtaining; Slab length change amount calculated as above ) To the target thickness Obtaining; Target thickness ) To open the horizontal roll Obtaining; And the horizontal roll opening obtained as described above ( After setting the opening degree of the horizontal roll according to), the hot plate rolling control method comprising the step of hot rolling the steel slab by a conventional method is the main point.

Description

Plate width control method during hot thick plate rolling

1 is a schematic diagram showing a thick plate rolling process

(A) of FIG. 2 is a schematic diagram showing the bread-making rolling process, (b) is sectional drawing along the line A-A of FIG. 1 (a), and (b) is sectional drawing along the line B-B of FIG.

3 is a schematic view showing a thick plate rolling process

* Explanation of symbols for the main parts of the drawings

1: slab, 2: edge roll, 3: horizontal roll

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plate width control method for rolling to a target plate width during thick plate rolling, and more particularly, to a breading machine for performing a breading roll using an edge roll and a horizontal roll 1. In the rolling process, the width of the slab in the width direction due to the edge rolling and the spreading amount due to the horizontal rolling are set so that the horizontal roll gap is set so that the width of the hot plate can be obtained during hot rolling. It is about.

In the conventional thick plate rolling process, as shown in FIG. 1, the slab 1 is subjected to even rolling in 1-2 passes, rotated by 90 °, and then rolled in 3-8 passes in a desired width. The final thick plate is manufactured by rotating it back to 90 ° and then passing the lengthwise rolling process of 6-16 passes. At this time, the width of the product is determined by the bread width rolling process.

However, when thick plate rolling is performed by the above-described conventional method, the slab 1 rotated by 90 ° has a phenomenon in which the slab length decreases in the width direction by edge rolling or the slab length increases due to thickness rolling. There is a problem that manufacturing is difficult due to the target plate width after the end of rolling.

The target thickness (Hr) for obtaining the target plate width during rolling is as shown in the following equation (1) from the volume constant condition.

Is expressed. Here, H _o , W _o , L _o represent the slab thickness, width, and length before the bake rolling, and H _r , W _r , L _r represent the target thickness, the target plate width, and the length after the bake rolling, respectively. . Assuming that there is no change in the slab length in the width direction before and after the spreading rolling in the formula (1), the target thickness Hr after rolling is expressed by the following formula (2).

Is expressed. When the target thickness is obtained in Equation (2), in consideration of the elastic recovery amount δi according to the thickness rolling pass schedule in the width-exposure rolling process, the horizontal roll opening degree S _{i for} each pass as shown in Equation (3) below. Will be set.

Where n is the number of bread roll rolling passes and βi is the i pass matching Is i pass thickness reduction rate.

The roll opening control method by calculating the target thickness of the conventional breading machine does not consider the influence of the decrease of the slab length in the width direction due to the edge rolling during the breading roll and the spreading amount due to the thickness rolling. There is no problem.

Accordingly, the present inventors conducted research and experiments to solve the problems of the conventional method described above, and based on the results, the present invention proposes the present invention. Hot rolled plate rolling that can obtain accurate target plate width by setting horizontal roll gap in consideration of reduction of slab length in the width direction by edge rolling and spreading by horizontal rolling It is to provide a width control method, which has a purpose.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated.

According to the present invention, in the hot rolling method of steel slab subjected to the width rolling by the edge roll and the horizontal roll, the slab length variation coefficient in consideration of the amount of slab length reduction in the width direction by the edge rolling and the spread amount due to the thickness rolling ( Obtaining C _L) by the following formula (4);

(Where A, B, m, n and r are regression coefficients for each influencer, which are values that change with the steel grade)

Using the slab length variation coefficient (C _L ) obtained as described above, the slab length variation ( Obtaining;

Slab length change amount calculated as above Using the following formula (5) exposing target thickness ( Obtaining;

Target thickness Using the following formula (6) the horizontal roll opening degree ( Obtaining; And

The horizontal roll opening degree obtained as described above ( And setting the opening degree of the horizontal roll according to the following), and then hot rolling the steel slab in a conventional manner.

Hereinafter, the present invention will be described in detail.

The present invention is applied to the hot rolling method of the steel slab 1 which performs breading rolling by the edge roll 2 and the horizontal roll 3 as shown in FIG. 2 and FIG.

In order to control the plate width according to the present invention, the slab length variation coefficient C _L must be obtained as shown in Equation (4).

here Is the amount of edging by edge rolling, C _L is the amount of change in slab length in the width direction after bread-rolling rolling, and A, B, m, n, and r are the regression coefficients for each of the influence factors. .

Next, using the slab length change coefficient C _L obtained above, the slab length change amount before and after the bake rolling is obtained by the following equation (4a).

Next, the amount of change in the slab length obtained as described above ( Using the following formula (5) exposing target thickness ( )

(W _O and L _O respectively represent the slab width and length before the bake rolling)

In the above, the target thickness Denotes the corrected target thickness in consideration of the amount of change in the slab length in the width direction before and after the rolling process.

The W _O , L _O can be measured from the width measuring sensor 4 as shown in FIG. 3.

Next, the breadth target thickness obtained as described above ( Using the following formula (6) the horizontal opening degree ( )

Next, the horizontal roll opening degree obtained as described above ( By setting the opening degree of the horizontal roll in correspondence with (), and then hot-rolling the steel slab in a conventional manner, a hot post-rolled sheet having a more accurate target plate width is produced.

Hereinafter, the present invention will be described in more detail with reference to Examples.

Example

Applying the plate width control method of the present invention to investigate the width-weight ratio, deviation between the width of the plate width, the results are shown in Table 1 below.

The material used was 566 sheets, and the width value was measured from the width measurement sensor.

TABLE 1

As shown in Table 1, it can be seen that the target plate width hit ratio and the plate-to-plate variation can be more effectively reduced when the present invention is applied.

As described above, the present invention has an effect of further improving the error rate of the thick plate product by more precisely controlling the plate width in consideration of the amount of change in the slab length in the width direction in the bread-making rolling process.

Claims (1)

In the hot rolling method of steel slab, which is rolled by edge roll and horizontal roll, slab length variation factor (C _L ) considering the amount of slab length reduction in the width direction by edge rolling and the amount of spread by thickness rolling To obtain the understanding in the following formula (4); (Where A, B, m, n and r are regression coefficients for each influencer, which are values that change with the steel grade) Using the slab length change coefficient (C _L ) obtained as described above, the slab length change amount ( Obtaining; Slab length change amount calculated as above Using the following formula (5) exposing target thickness ( Obtaining; Target thickness Using the following formula (6) the horizontal roll opening degree ( Obtaining; And The horizontal roll opening degree obtained as described above ( The method of controlling the width of a hot rolled plate according to the method comprising the steps of setting the opening degree of the horizontal roll and then hot rolling the steel slab in a conventional manner.