JPS6390310A - Width control method for hot strip mill - Google Patents

Abstract

PURPOSE:To reduce width variations of both a width spreading and a width reducing part and to improve the quality by correcting the opening changing pattern amount of the previously set roll opening of a vertical rolling mill based on a rolled stock on the outlet side of a horizontal rolling mill. CONSTITUTION:The top unsteady part of a rolled stock 2 is divided into a region I (0<=x<=lT) and a region II (lT<=x<=LT). Where, (x) is a distance from the top of the stock 2 and lengths lT, LT determining respective regions are determined as a function of a width and a thickness of the stock 2 on the vertical rolling mill 1 and a preset opening and a roll diameter of the mill 1. As for correction of a roll opening changing pattern value, width variation of the unsteady part is reduced by correcting the roll opening changing pattern value of the mill 1 by equations I and II. In the equations, x(i) is a pattern length and DELTAW3 is a width deviation on the outlet side of a horizontal rolling mill 3. Also, the pattern correction method for the rear end of the stock 2 is the same method as that for the top end.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application> The present invention relates to a method for controlling strip width in a hot strip mill.

<Prior art> The schematic configuration of a rough rolling mill is shown in Fig. 1. In the figure, 1 is a rolled material 2
3 is a horizontal rolling mill that rolls down the rolled material 2 in the width direction; 4 and 5 are the board width measuring machine 1 that detects the width of the rolled material 2; and the horizontal rolling mill 3. Then, at the front and rear ends of the rolled material 2, the width reduction due to width rolling and the width widening due to horizontal rolling are superimposed, resulting in sheet width variation as shown in FIG. 2. This area of plate width fluctuation is called the unsteady part. Conventionally, in order to suppress the fluctuation range of the unsteady part, the amount of change in the vertical rolling mill roll opening was determined using the following formula.

ΔW (xl = G (xl...(1)
- This is a value obtained by interpolating the amount of negative energy (see Fig. 3). The amount of the opening change pattern is set in advance for stratification based on the steel type, width reduction amount, and the like.

<Problems to be Solved by the Invention> However, even if the plate width of the rolled material is controlled using the above-mentioned equation (1), variations in the plate width remain due to errors in the opening degree change pattern.

The present invention has been made in view of the above-mentioned circumstances, and provides a strip width control method for a hot strip mill that can reduce strip width fluctuations in unsteady parts of rolled materials, thereby improving the quality of rolled materials. The purpose is to

Means for Solving the Problems> The method of the present invention for achieving the above object is to provide a rough rolling mill of a photo strip mill consisting of a vertical rolling mill and a horizontal rolling mill, in which rolling on the exit side of the horizontal rolling mill is carried out. To reduce strip width fluctuations at the width widening portion and the width dropping portion by correcting the amount of the opening degree change pattern of the vertical rolling roll set in advance based on the plate width detection values at the width widening portion and the width dropping portion of the material. It is characterized by

Examples> The present invention will be described in detail. As shown in Figure 2, due to the difference in deformation mechanism, the unsteady part at the leading and trailing ends of the rolled material 2 is
(0≦X≦1), region II (jTSx≦Lr), region ■ (--4≦X≦--1,), region V (L4)-j'
, ≦X≦−). However, X is the distance from the tip of the rolled material 2, and the length l□71-'T#j that determines each area
, L, and L are values determined as functions of the plate width and plate thickness of the filter-rolled material 2 on the entrance side of the vertical rolling mill 1, the preset opening degree of the vertical rolling mill 1, and the roll diameter.

Next, a method of correcting the opening degree change pattern value will be explained.

However, since the pattern correction method for the rear end of the rolled material 2 is the same as that for the front end, it will be omitted.

Pattern value GP'''(i)(l:
1 to 4) are the values CP'(i) used this time (see Figure 3)
It is given by the following formula using G P''' (i) → calculated from the current rolling results.

GP”'fi) = (I K11I) GP'!il
+, ·G P''' (il... (2) Ko is an exponential smoothing gain and is a value given as appropriate based on the rolling results. Also, G P''' (il is given by the following formula.

GP'''[1)=GP'(i)-ΔW, --(310
When ≦X (i)≦lT, Δw, = Ding 2 Ding △W, (xi d x / j ,
--(4) I, <x (ΔV/ when il≦LT, = guess ΔW3(x)dx/(LT-j,) −
・−・−(5) However, x (i) If the pattern length is 3rd
(see figure), ΔW3 is the exit side plate width deviation of horizontal rolling Ia3.

Based on the above calculation formula, the amount of the opening change pattern of the rolls of the vertical rolling mill 1 is corrected to reduce strip width fluctuations in the unsteady portion.

In this embodiment, five pattern values are set, but by increasing the number, the precision of the pattern can be further improved.

<Effects of the Invention> The hot strip mill strip width control method of the present invention can reduce the error in the roll opening change amount of the vertical rolling mill with respect to the target strip width, so that strip width fluctuations at the leading and trailing ends of the rolled material can be reduced. can be made smaller. As a result, it becomes possible to improve the quality of the rolled material.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a rough rolling mill, FIG. 2 is a plan view of a rolled material in which strip width variation has occurred, and FIG. 3 is a graph showing the amount of opening change patterns. In the drawing, 1 is a vertical rolling mill, 2 is a rolled material, 3 is a horizontal rolling mill, and 4.5 is a strip width gauge.

Claims (1)

[Claims] In the rough rolling mill of a photo strip mill consisting of a vertical rolling mill and a horizontal rolling mill, vertical rolling is preset based on the plate width detection values of the width widening part and the width dropping part of the rolled material at the exit side of the horizontal rolling mill. A method for controlling strip width in a hot strip mill, characterized by reducing variations in strip width at width widening portions and width dropping portions by modifying the opening degree change pattern amount of machine rolls.