JP2003039108A - Meandering control method for thin slab - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a meandering control method for controlling meandering of a strip slab in a process of rolling and winding a strip slab manufactured by a twin-drum continuous casting machine by a hot rolling mill. I do. SOLUTION: In a meandering control method for controlling meandering of a strip cast manufactured by a twin-drum type continuous casting machine, a meandering amount of the strip cast is detected at at least two points on an entrance side of a hot rolling mill. The difference between the left and right gaps in the hot rolling mill is adjusted based on the difference in the meandering amount to correct the meandering of the strip slab.
It is preferable that the meandering amount is detected at least at two positions sandwiching a pinch roll (preferably the nearest neighbor) on the hot rolling mill entry side. Further, it is preferable that the speed of the pinch roll is detected, and the left and right reduction amount of the pinch roll and / or the gap difference between the left and right of the hot rolling mill are adjusted based on the difference between the detected speed and the meandering amount.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin strip cast produced by a twin-drum type continuous casting machine by a hot rolling mill so that the strip strip does not meander during rolling. The present invention relates to a meandering control method for controlling traveling of one piece.

[0002]

2. Description of the Related Art A strip cast produced by a twin-drum type continuous casting machine is hot-rolled by a required reduction amount (for example, about 25 to 50%), and then wound by a winding machine. However, in this process, the strip slab may meander.

The cause of meandering of the thin strip slab is (a)
Difference in plate thickness between the left and right of the thin strip, temperature difference, and (b)
Disturbances due to thermal deformation of pinch rolls and other rolls are possible. Further, the meandering in the hot rolling mill causes a secondary meandering in the upstream pinch roll.

That is, the strip cast product that has left the twin-drum type continuous casting machine is provided to the hot rolling machine while being sandwiched by pinch rollers. If there is a difference in thickness, or if the amount of reduction on the left and right is unmatched with respect to the difference in strip thickness or the difference in temperature during hot rolling,
The strip slab begins to meander, and in some cases after hot rolling,
It also meanders until the strip slab is wound up by the winder.

Since the thin strip slab is in a high temperature state and is easily deformed, a guide roller, a
Since a device such as a guide that restricts the movement in the width direction is not attached, once the thin strip slab starts to meander, even if the reduction amount of the pinch roller is adjusted, the thin strip slab will not move.
The reality is that it cannot be resolved easily.

If the strip slab meanders even after hot rolling, winding work will be hindered and the slab will suffer from ear bending, and in extreme cases, plate rupture will occur. There is a strong demand for the development of a technology for controlling the meandering of the.

In the twin drum type continuous casting, a dancer roll or a free loop may be provided behind the pinch roll in order to suppress the meandering of the strip slab. However, in this case, there are problems that (a) the line length becomes long, (b) the equipment cost is high, or (c) the temperature before the mill is high so that the dancer roll cannot be used.

Usually, even when continuous casting materials such as slabs and blooms are hot-rolled by a continuous rolling mill train, the left and right bends of the continuous casting material itself and the uneven left and right rolling amount of the rolling mill itself are the causes. In some cases, the hot-rolled material meanders. For the meandering of the hot-rolled material, various techniques for controlling the meandering have been developed.

For example, in Japanese Unexamined Patent Publication No. 2-20608, the meandering amount of the rolled material is detected on the inlet side and the outlet side of the rolling mill in a continuous rolling mill train, and the meandering on the inlet and outlet sides of each rolling mill is detected. The difference between the amounts is calculated as a meandering amount deviation, and among the abnormal rolling mills in which the meandering amount deviation exceeds a predetermined value, the meandering amount deviation is zero for the abnormal rolling mill on the most upstream side. There is disclosed a meandering control method for a rolled material in a continuous rolling mill, which comprises performing a reduction adjustment by operating a reduction amount difference between a driving side and an operating side of the rolling mill.

In this meandering control method, (1) the meandering amount of the rolled material in the upstream stand influences the meandering amount of the downstream stand, and (2) the meandering amount of the rolled material in the downstream stand is equal to that of the upstream stand. It is based on the knowledge that it does not affect the meandering amount, and in the continuous rolling mill train, when the continuous cast material is hot-rolled under the required tension,
It is effective.

However, in reality, the meandering amount of the rolled material in the downstream stand affects the meandering amount of the upstream stand, and the meandering control method does not track the meandering of the rolled material. It is not possible to specify the equipment that is causing the cause of the above, and after all, the above meandering control method is not necessarily an optimum meandering control method.

Even if the difference in the meandering amount between the stands is simply (without tracking), when the strip strips meander independently in the upstream and the downstream, the meandering amount component in the actual rolling mill is If you do not correctly grasp and suppress the meandering, the meandering will expand.

Therefore, in the meandering control of the thin strip slab, it is required to elucidate the peculiar cause of the meandering of the thin strip slab and to develop an optimum meandering control technique.

[0014]

SUMMARY OF THE INVENTION In view of the above development demand, the present invention does not meander the strip slab in the process of hot rolling and winding the strip slab cast by a twin drum type continuous casting machine. Thus, it is an object of the present invention to provide a meandering control method for controlling the traveling of a strip cast.

[0015]

Means for Solving the Problems As a result of an in-depth analysis of the meandering phenomenon of a strip slab, the present inventor has found that the amount of strip slab meandering in a downstream rolling mill is determined by the meandering in an upstream rolling mill or a pinch roll. It has been found to affect quantity.

The meandering control method described in Japanese Patent Laid-Open No. 20608/1990 is based on the knowledge that the meandering amount of the rolled material in the downstream stand has almost no effect on the meandering amount in the upstream stand. However, as a result of the above-mentioned analysis, the present inventor found out the opposite findings.

The present invention is based on the above new findings, and the gist thereof is as follows.

(1) In a meandering control method for controlling the meandering of a strip slab produced by a twin-drum type continuous casting machine, the meandering amount of the strip slab is adjusted at least at two points on the inlet side of the hot rolling mill. A meandering control method for a thin strip slab, which comprises detecting and correcting the meandering of the strip slab by adjusting the left-right gap difference in the hot rolling mill based on the difference in the meandering amount.

(2) In a meandering control method for controlling the meandering of a strip slab produced by a twin-drum type continuous casting machine, the meandering amount of the strip slab is adjusted at least at two points on the inlet side of the hot rolling mill. Detecting, based on the difference in the meandering amount, by adjusting the difference between the left and right rolling force or the load difference in the hot rolling mill, the meandering of the thin strip slab is corrected. Control method.

(3) In the method for controlling the meandering of the strip slab according to the above (1) or (2), the strip slab meandering is performed at least at two positions sandwiching the pinch roll on the inlet side of the hot rolling mill. A method for controlling the meandering of a thin strip slab, which is characterized by detecting the amount.

(4) In the method for controlling the meandering of the strip cast as described in (3) above, the speed of the pinch roll is detected,
A meandering control method for thin strip castings, which comprises adjusting a left-right gap difference in a pinch roll and / or a left-right gap difference in a hot rolling mill based on the difference between the detected speed and the meandering amount. .

(5) In the meandering control method for a strip cast as described in (3) or (4) above, the speed of the pinch roll is detected, and the pinch roll is detected based on the difference between the detected speed and the meandering amount. The method for controlling the meandering of the strip slab is characterized in that the meandering of the strip slab is corrected by adjusting the gap difference between the left and right in the above, and the pressure difference or the load difference between the left and right in the hot rolling mill.

(6) In the meandering control method for a thin strip casting according to any one of (3) to (5), the speed of the pinch roll is detected, and the difference between the detected speed and the meandering amount is detected. Based on the above, the meandering amount component by the pinch roll adjusts the left and right gap difference in the pinch roll, and the meandering amount component by the hot rolling mill is characterized by adjusting the left and right gap difference in the hot rolling mill. A meandering control method for thin strip slabs.

(7) In the meandering control method for a strip cast as set forth in any one of (3) to (6), the position of the pinch roll is closest to the hot rolling mill. A method for controlling meandering of a thin strip slab, comprising:

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described with reference to FIG. FIG. 1 is a diagram illustrating an aspect of the present invention.

The thin strip slab 1 is sandwiched between pinch rolls 2a and 2b, conveyed, hot-rolled by a hot rolling mill 3, and wound by a winder (not shown). This hot rolling-
In the winding line, pinch rollers 2a and 2b are installed on the inlet side of the hot rolling mill 3, and meandering sensors 4p and 4q are arranged before and after the pinch rollers 2a and 2b.

In the present invention, the meandering sensors 4p and 4
Each of q is composed of a pair of left and right sensors, and detects the "amount of deviation from the center of the hot rolling-winding line" in the width direction of the strip slab 1, that is, the meandering amounts Mp and Mq.

According to the present invention, the meandering amount of the strip slab is thus detected at at least two points on the inlet side of the hot rolling mill, so that the strip slab meanders on the running line. You can specify the position.

That is, the meandering amount Mq detected by the meandering sensor 4q is tracked to the meandering sensor 4p. Then, the difference from Mp detected by the meandering sensor 4p is calculated. The difference "Mp-Mq" is the meandering amount corresponding to the meandering generated in the strip slab that is running in the hot rolling mill. On the other hand, Mp = Mq when the meandering is not generated in the strip slab in the hot rolling mill.

Further, if the gap difference between the left and right in the hot rolling mill is adjusted only by the meandering amount Mp detected by the meandering sensor 4p, the meandering of the strip slab may be promoted. This is because the pinch rollers 2a and / or 2b cannot completely correct the meandering, and the meandering amount corresponding to the remaining meandering is
This is because it is included in the meandering amount Mp.

The above meandering amounts Mp and Mq are inputted to the meandering control device 7, and the value of "Mp-Mq", the sheet thickness t and the sheet width w of the thin strip cast which have been inputted in advance, and the thin strip casting. Actual temperature T of one piece
Based on the actual speed V and the actual speed V, the difference "Rm" between the left and right gaps in the hot rolling mill necessary to eliminate the meandering of the strip slab on the inlet side of the hot rolling mill according to a predetermined calculation formula.
To calculate.

Then, the reduction controller 5 is controlled on the basis of the gap difference "Rm" to adjust the left and right reduction amounts of the hot rolling mill to meander the strip slab on the inlet side of the hot rolling mill. To eliminate.

As shown in FIG. 2, the amount of reduction on the left and right sides of the hot rolling mill is adjusted by adjusting the gap (Gc) at the center of the roll.
Work side of upper work roll 9 (WS)
The gaps Gw and Gd on the drive side (DS) side and the drive side (DS) side are changed by the same amount in opposite directions.

When the gap (Gc) at the center of the roll is changed, the strip thickness of the strip is changed. Therefore, only one of the reduction amounts is changed, or the left and right reduction amounts are different in the opposite directions. Basically, no adjustments are made.

As described above, in the present invention, the meandering amount of the strip slab is detected at at least two points on the entrance side of the hot rolling mill, and the entrance side of the hot rolling mill is detected based on the meandering amount. The location of the meandering of the strip slab and the equipment that causes the meandering (whether it is a pinch roll or a hot rolling mill) are specified, and heat is applied until the location of the meandering reaches the hot rolling mill. It is possible to eliminate the meandering of the strip slab on the inlet side of the hot rolling mill by appropriately adjusting the left and right reduction amounts in the hot rolling mill. This is a feature of the present invention.

When the meandering of the strip slab is eliminated on the inlet side of the hot rolling mill, the strip slab does not meander even on the outlet side of the hot rolling mill, and the winding is smooth. Since it can be carried out, it is possible to maintain good surface properties and quality of the strip cast.

Here, the arithmetic expression for calculating the left-right gap difference "Rm" is obtained by statistically analyzing the relationship with the meandering amount difference "Mp-Mq".

For example, the above arithmetic expression can be expressed by a linear function of "Mp-Mq" as in the following expression (1), but can also be expressed by other functional forms.

Rm = a * (Mp-Mq) + b * meandering speed (1) where a and b are the thickness t of the thin strip slab.
Is a constant determined by the strip width w, the temperature T of the thin strip slab, and the speed V, and the meandering speed is the amount of meandering per unit time.

That is, the above equation is used to calculate the meandering of the thin strip slab,
Any form of function may be used in terms of faster and more accurate control.

Further, in the present invention, in order to make the speed and accuracy of the meandering control more reliable, the above statistical analysis is performed including the speed V of the pinch roll 2a detected by the speed detecting device 8. May be performed to obtain an arithmetic expression, and the meandering control of the thin strip slab may be performed according to the arithmetic expression.

In this case, in order to make the meandering control by the gap difference "Rm" in the hot rolling mill quick and appropriate, the left and right reduction amounts of the pinch roll 2a are adjusted.

According to a preset arithmetic expression, the above "R
m "and the gap difference" Ra "to be adjusted in the pinch roll 2a is calculated, and the" Ra "is input to the reduction control device 6a to adjust the left and right reduction amounts in the hot rolling mill by the reduction control device 5. And pinch roll 2
Adjust the left and right reduction amounts at a.

Furthermore, when the amount of meandering is large, the amount of reduction on the left and right of the pinch roll 2b may be adjusted in order to control the amount of meandering more quickly.

The gap difference "Rb" calculated by the above equation
Is input to the reduction control device 6b, and the left and right reduction amounts of the hot rolling mill 3 are adjusted by the reduction control device 5 as well as the left and right reduction amounts of the pinch rolls 2b.

At this time, the left and right rolling reduction amounts of the pinch roll 2a may be adjusted appropriately and as needed.

In FIG. 1, the meandering sensors 4p and 4q are
Although the embodiment provided before and after the pinch roll 2a closest to the hot rolling mill has been illustrated, the pinch roll is not limited to the one closest to the hot rolling mill, and the meandering sensor includes a plurality of pinch rolls. It may be sandwiched between. Further, the meandering sensor may be provided at three or more places, if necessary.

[0048]

(Embodiment 1) In a thin strip slab traveling on a pinch roll, an upstream meandering amount Mq and a downstream meandering amount M.
It was detected that each of them was 10 mm. in this case,
Since Mq = Mp, there is no meandering in this limit, but the center of the thin strip slab is deviated from the line center, which causes the meandering in the hot rolling mill, so the deviation amount is Mq = 0.
In the pinch roll on the downstream side, the amount of reduction on the left and right was changed in the opposite direction by the same amount to adjust the gap difference.

(Example 2) In the strip slab being rolled by the hot rolling mill, the inlet side meandering amount Mq is 0 and the outlet side meandering amount Mp is 1.
Since it was detected that it was 0 mm, Mp-Mq = 10 was 0.
In the hot rolling mill, the gap difference was adjusted by changing the left and right reduction amounts by the same amount in opposite directions. Also, Mq
The pinch roll was adjusted so that = 0.

[0050]

According to the present invention, a strip cast produced by a twin-drum type continuous casting machine is rolled by a hot rolling mill and wound in a winding process so that the strip cast does not meander. Since the traveling of the strip can be controlled, the thin strip slab can be stably wound up without occurrence of ear bending or the like. It can be hot-rolled without impairing its uniform shape and then wound. And if this thin strip slab is cold rolled,
It is possible to obtain an excellent product thin plate having a uniform shape and quality.

[Brief description of drawings]

FIG. 1 is a diagram schematically illustrating an embodiment of the present invention.

FIG. 2 is a diagram schematically showing an aspect of adjusting a gap difference in a hot rolling mill.

[Explanation of symbols]

1 ... Thin strip cast 2a, 2b ... Pinch roll 3 ... Hot rolling mill 4p, 4q ... meandering sensor 5, 6a, 6b ... Rolling-down control device 7. Meandering control device 8 ... Speed detection device 9 ... Top work roll 10 ... Lower work roll t ... Plate thickness (preset value) w ... Board width (preset value) T ... Temperature (actual value) V: Speed (actual value) Mp, Mq ... meandering amount Rm, Ra, Rb ... Gap difference

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B22D 11/06 330 B21B 37/00 135 11/12 BBH 11/16 104 142A 144 (72) Inventor Ryuta Tsukamoto 3434 Shimada, Hikari City, Yamaguchi Prefecture Shin-Nippon Steel Co., Ltd. Hikari Steel Co., Ltd. F-term (reference) 4E004 DA13 NB01 SE01 4E024 BB18 CC01 CC02 FF10

Claims (7)

[Claims] 1. A meandering control method for controlling the meandering of a strip slab produced by a twin-drum type continuous casting machine, wherein the meandering amount of the strip slab is detected at at least two points on the inlet side of the hot rolling mill. Then, the meandering control method of the strip slab is characterized in that the meandering of the strip slab is corrected by adjusting the left-right gap difference in the hot rolling mill based on the difference in the amount of the slab. 2. A meandering control method for controlling the meandering of a strip slab produced by a twin-drum type continuous casting machine, wherein the meandering amount of the strip slab is detected at at least two points on the inlet side of the hot rolling mill. Then, based on the difference in the amount of meandering, the meandering control of the thin strip slab is characterized in that the meandering of the thin strip slab is corrected by adjusting the left-right rolling force difference or the load difference in the hot rolling mill. Method. 3. The meandering control method for a strip strip according to claim 1, wherein the meandering amount of the strip strip is detected at at least two positions sandwiching the pinch roll on the inlet side of the hot rolling mill. A method for controlling meandering of a thin strip slab, comprising: 4. The method for controlling the meandering of a strip cast product according to claim 3, wherein the speed of the pinch roll is detected, and based on the difference between the detected speed and the amount of meandering, the gap difference between the left and right of the pinch roll, Also, a meandering control method of a strip slab is characterized in that the meandering of the strip slab is corrected by adjusting a left-right gap difference in the hot rolling mill. 5. The method for controlling meandering of a strip cast according to claim 3 or 4, wherein the speed of the pinch roll is detected,
Based on the difference between the detected speed and the amount of meandering, the left and right gap difference in the pinch roll and the left and right pressure difference or load difference in the hot rolling mill are adjusted to correct the meandering of the strip slab. A method for controlling meandering of a thin strip slab, comprising: 6. The meandering control method for a thin strip cast product according to claim 3, wherein the speed of the pinch roll is detected, and based on the difference between the detected speed and the meandering amount.
The meandering amount component by the pinch roll adjusts the left and right gap difference in the pinch roll, and the meandering amount component by the hot rolling mill adjusts the left and right gap difference in the hot rolling mill. Meandering control method. 7. The method for controlling the meandering of a strip cast according to claim 3, wherein the pinch roll is located closest to the hot rolling mill. Method for controlling meandering of thin strip slab.