KR19980048889A - Method of overlapping control of plate edge during hot thick plate rolling - Google Patents

Abstract

The present invention relates to a method for controlling the overlapping of the plate edge portion during hot plate rolling, and to control the abnormal deformation generated at the leading end and the rear end based on the rolling direction during the deburring rolling during the thick plate rolling process Overlap control of plate edge during hot plate rolling to control the amount of edge overlap of the final blade by changing the shape of slab edge by changing the roll gap of line and rear end as much as non-normal part in the first pass. The purpose is to provide a method.

The present invention relates to a method for rolling hot slab of steel slab subjected to a bake rolling, the method comprising: obtaining an amount of overhang occurrence (ΔW _p ) to occur at a line and a rear end under a given rolling condition; Obtaining a roll gap correction amount Δh _{c such that the} overhang generation amount ΔW _p obtained as described above satisfies the allowable overhang generation amount ΔW _p ^o ; Obtaining roll opening degrees (S _t , _b ) of the front end and the rear end to be applied during the first pass of the bake rolling by using the roll gap correction amount? H _c obtained as described above; And setting the roll opening degrees at the front end and the rear end corresponding to the roll opening degree (S _{t, b} ) values obtained as described above _, followed by hot-rolling in the usual manner from the two-pass roll-rolling process after hot-rolling in the usual manner. Edge overlap control method at the time of hot thick plate rolling comprising a.

Description

Method of overlapping control of plate edge during hot thick plate rolling

1 is a perspective view showing a thick plate rolling process

Figure 2 is a schematic diagram showing the process of overlapping plate edge portion occurrence phenomenon

3 is a schematic view of a roll opening correction pattern in accordance with the present invention;

Figure 4 is a schematic diagram of a model rolling test method for showing the effect of the present invention

* Description of the symbols for the main parts of the drawings *

1: slab 2: horizontal roll

[Purpose of invention]

[Technical Field to which the Invention belongs and Prior Art in the Field]

The present invention relates to a method of controlling the overlapping of the plate edge portion during hot plate rolling, and more particularly, to control the abnormal deformation generated at the leading end and the rear end based on the rolling direction during the deburring rolling during the thick plate rolling process. In the first pass of hot-rolling rolling, hot rolled plate for high precision plate width can be obtained by controlling the overlapping amount of edge part of final blade by changing the shape of slab edge by changing roll gap of line and rear end as much as non-normal part. An edge overlap control method.

In general, in the thick plate rolling process, as shown in FIG. 1, the slab 1 is manufactured by three stages of rolling, such as sizing, broadside rolling, and length-finishing. . In other words, the slab extracted from the heating furnace is subjected to even rolling in one or two passes, the slab is rotated by 90 °, and the width of the slab is rolled in three to eight passes to make the target plate width. After the rotary process, the final plate product is manufactured through a length rolling process of 6 to 16 passes.

However, as shown in FIG. 2, the top and bottom portions of the raw material during the rolling process during the thick plate rolling process, respectively, in the slab thickness direction, which is a contact portion between the roll and the raw material, Due to the difference in the metal flow, the abnormal deformation is present. Hereinafter, the abnormal deformation portion generated during the rolling process is called an overhang. Since the slab with the overhang is rotated by 90 ° again after the end of the roll width rolling, the slab remains on both edges of the plate width direction and overlaps with each other. To develop. The amount of overlap is increased as the thickness before rolling is increased and as the rolling ratio is increased. In the case of the disintegrating material, the shear amount of the plate is caused by causing side cropping of about 20 to 30 mm in the width direction of the plate. By increasing, there is a problem of lowering the real rate.

Accordingly, the present inventors conducted research and experiments to solve the above problems, and based on the results, the present invention proposes the present invention, and the present invention exposes the overhang portion of the line and the rear end generated during the bake rolling. In the first pass, hot rolled sheet rolling can reduce the edge side edges of the final blade state by changing the shape of the slab in advance by changing the roll gap in the corners of the slab based on the rolling direction. An object of the present invention is to provide a method of overlapping plate edge control.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated.

The present invention provides a method for rolling hot slab of steel slab subjected to breading and rolling, the method comprising: obtaining an amount of overhang occurrence (ΔW _p ) occurring at a line and a rear end under a given rolling condition by the following equation (1);

… … … … … (One)

[Where Δh _c is the line, the rear end roll gap correction amount, γ _w is the width of the roll width, H _o , W _o is the thickness and width of the width of the width, and L _d is the projection contact length between the roll and the material]

Obtaining a roll gap correction amount Δh _c at which the overhang generation amount ΔW _p obtained as described above satisfies the allowable overhang generation amount ΔW _p ^o using Equation (2);

… … … … … (2)

Using the slab roll gap correction amount (Δh _c ) obtained as described above, obtaining the roll opening degrees (S _t , _b ) of the front and rear ends to be applied during the first pass of the blasting rolling by the following equation (3); And

… … … … … (3)

Where x is the distance from the tip to an arbitrary position relative to the width of the slab, ΔW ₁ : roll gap correction length, Δh ₁ is the horizontal drop rate at the top of one pass, and δ ₁ : Elastic recovery amount), the roll opening degree of the front end part and the rear end part are set to correspond to the roll opening degree S _{t, b} calculated | required above, and the roll opening degree of the top part is set to the roll opening degree S ₁ calculated by following formula (4). Set it to match,

… … … … … (4)

After rolling one pass of the bake, the second pass of the bake roll relates to a method for controlling the overlapping of the edge portion at the time of hot thick plate rolling comprising the step of hot rolling under normal conditions.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

The present invention is a hot slab rolling method of steel slab subjected to the deburring rolling, in which the overhang occurring during the deburring rolling is predicted in advance, and the roll gap is set by calculating the line and rear end roll gap variation which minimizes the roll slag and minimizes the rollover. The present invention relates to a method of controlling the overlap of plate edges during hot rolling of steel slabs and hot thick plate rolling using a conventional roll gap setting method.

In order to control the overlapping of the sheet edge portion according to the present invention, given the thickness, width, width of the width rolling mill and the pass schedule before the width of rolling, it is necessary to obtain the amount of overhang (ΔW _p ) using the following formula (1).

… … … … … (One)

Where Δ h _c is the amount of roll gap correction at the front and rear ends, γ _w is the breadth rolling ratio, and is defined as the ratio of the target plate width and slab width, H _o , W _o are the thickness and width of the breading roll, and L _d is Projection contact length between roll and material.

An example of the above formula (1) may be expressed as the following formula (1a).

… … … … … (1a)

(In the formula (1a), K ₁ , K ₂ , K ₃ , K ₄ , K ₅ represents a regression coefficient.

Next, using the overhang amount (△ W _p) is permitted overhang amount (△ W _p ^o) roll gaepsu amount (△ h _c), the following from the formula (1) formula (2) satisfying the determined as described above Obtain it by

In the present invention, a more preferable allowable overhang generation amount ΔW _p ^o is 10 mm or less.

… … … … … (2)

Using the roll gap correction amount (Δh _c ) obtained as described above, the roll opening degree (S _t , _b ) of the leading end portion and the rear end portion to be applied during the first pass of the explosive rolling, in consideration of the elastic recovery amount of the roll (δ ₁ ) Obtained by (3).

… … … … … (3)

The △ △ h _c and W ₁ schematically it is shown in FIG. 3.

And a roll of the top opening (S ₁₎ can be calculated as shown in the following formula (4).

… … … (4)

In equations (3) and (4), Δh _c is the thickness reduction given in the first pass of the rolling _process , ΔW ₁ is the roll gap correction length, and the hydraulic cylinder reduction of the AGC (Automatic gauge control) facility and the cylinder It is the value automatically given by the following equation (5) from the functional relationship with the speed.

… … … … … (5)

Here, V _r represents the rotational speed of the roll, and V _c represents the hydraulic cylinder reduction amount of the horizontal roll, respectively.

Next, the roll opening degree obtained at the front end and the rear end was set to the roll opening degree value obtained in the above (3), and the roll opening degree at the top was set to the roll opening degree value obtained in the formula (4). From the post-exposure roll 2 pass, the steel slab can be hot rolled under normal conditions to eliminate edge overlap.

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

EXAMPLE

When the conventional rolling method and the line and rear end roll gap correction methods of the present invention were applied, simulation tests were performed in which the size was similar to that of 1/10 of the implementation to prove the effect. The material used in this embodiment is plasticine, which is useful for simulating the deformation behavior during rolling because the deformation property at room temperature is similar to the deformation property of hot soy at high temperature. In the simulation experiment, as shown in FIG. 4, chamfers were applied to the edges of the slab front end and the rear end, respectively, and the explosive rolling was performed according to the pass schedule as shown in Table 1. At this time, the mote amount was determined by calculating the minimum roll gap correction amount from the overhang generation amount prediction formula proposed in the present invention. In the example of the present invention, three model rolling experiments were performed under the conditions shown in Table 2 below.

That is, while the conventional example was rolled under the conditions of Table 1, the invention example was rolled under the conditions of Table 1, but when the first pass rolling, the roll gap was corrected after modifying the roll gap at the trailing end as shown in Table 2 below. .

As shown in Table 3 below, the results of a thick plate generation amount rolled as described above were measured and averaged.

TABLE 1

TABLE 2

TABLE 3

As shown in Table 3, it can be seen that the use of the present invention can significantly reduce the amount of plate overlapping when using the conventional rolling method.

As described above, the present invention has the effect of reducing the overlapping of the edge portion of the final blade state by improving the thickness plate error rate by giving a predetermined amount of roll gap variation to the front and rear ends in the first pass of the thick plate width rolling process. .

Claims (3)

In the hot thick plate rolling method of the steel slab subjected to the depoking rolling Obtaining an overhang generation amount ΔW _{p that} will occur at a line and a rear end under a given rolling condition by the following equation (1); … … … … … (One) [Where Δh _c is the line, the rear end roll gap correction amount, γ _w is the width of the roll width, H _o , W _o is the thickness and width of the width of the width, and L _d is the projection contact length between the roll and the material] Obtaining a roll gap correction amount Δh _c at which the overhang generation amount ΔW _p obtained as described above satisfies the allowable overhang generation amount ΔW _p ^o using Equation (2); … … … … … (2) Using the slab roll gap correction amount (Δh _c ) obtained as described above, calculating the roll opening degrees (S _t , _b ) of the front and rear ends to be applied during the first pass of the blasting rolling by the following equation (3); And … … … … … (3) (Where x is the distance from the tip to an arbitrary position in relation to the width direction of the slab, ΔW ₁ : roll cap modification length) Set the roll opening degree of the front end part and the rear end to correspond to the roll opening degree S _{t, b} obtained above, and set the roll opening degree of the top part to correspond to the roll opening degree S ₁ obtained by the following formula (4) , … … … … … (4) Method of overlapping plate edge overlap during hot thick plate rolling comprising the step of hot-rolled sheet rolling, after rolling one pass, the hot rolled rolling two passes. The method according to claim 1, wherein formula (1) is represented by the following formula (1a), … … … … … (1a) Control method of overlapping plate edge portion during hot thick plate rolling characterized in that it is displayed. 3. The method according to claim 1 or 2, wherein the allowable overhang occurrence amount (ΔW ^o ) is 10 mm or less.