JPH0952108A - Method for transporting thin band-shaped cast slab - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably execute rolling by preventing meandering of a thin band- shaped cast slab which is continuously cast and sent to a coiler. SOLUTION: In the manufacture of the thin band-shaped cast slab in which the thin band-shaped cast slab S which is continuously cast using cooling drums 1, 1 is transported on a transporting line and coiled into a coil shape with a coiler 6, at least pinch rolls 4, tension adjusting device 7 and rolling mill 5 are arranged in order on the rear side of the cooling drums 1, 1, the tension of the cast slab on the outlet side of the pinch rolls 4 is maintained at <=0.05N/mm<2> and the tension of the cast slab on the inlet side of the rolling mill 5 is maintained at 0.05-0.15N/mm<2> .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a manufacturing technique for a thin strip-shaped slab that is continuously cast by using a cooling drum and is then wound into a coil by a winder while being conveyed on a conveyor line. In particular, it relates to a method for preventing the meandering of thin strip-shaped slabs sent from a cooling drum to a winder.

[0002]

2. Description of the Related Art FIG. 1 shows an outline of an apparatus for conveying a strip-shaped slab continuously cast by a cooling drum to a winder. A pair of cooling drums 1, 1 rotating in the direction of the arrow, and a pair of side dams 2 pressed against both end surfaces of the cooling drums 1, 1.
The molten metal M is supplied to the molten metal pool 3 formed by 2 and. The molten metal M is solidified on the peripheral surfaces of the cooling drums 1 and 1 to form a thin strip slab S having a plate thickness of 1 to 10 mm and a width of 700 to 1400 mm. The thin strip-shaped slab S is sent out downward and is sent to the rolling mill 5 by the pinch rolls 4 and 4 which are rotationally driven to be rolled and then wound up by the winder 6. A cooling device or the like may be installed between the pinch rolls 4 and 4 and the winder 5.

By the way, the strip-shaped cast slab S passing through the pinch roll 4 and the rolling mill 5 has a non-uniform shape, thickness or temperature in the width direction, and further reduction in the slab width direction in the pinch roll 4 and the rolling mill 5. It may meander due to uneven force. The meandering thin strip-shaped slab S strongly collides with a guide or the like (not shown) to cause flaws, and when the meandering is severe, it may be impossible to convey. Further, the edge of the thin strip-shaped cast slab S wound around the winder 5 becomes uneven, which hinders the work in the next step.

Conventionally, as a meandering correction method for a plate material such as a strip-shaped cast piece, a meandering correction method in cold rolling is known, for example, from Japanese Patent Laid-Open No. 59-191510. This method is a method in which a meandering detector is installed on the entrance side of the rolling mill to detect the meandering amount of the rolled material, and the roll gaps on the working side and the driving side are adjusted according to the detected meandering amount.

[0005] A meandering correction method for the passing of a strip is known, for example, from Japanese Patent Application Laid-Open No. 52-120942. In this method, a meandering detector is installed in the band passing line of the band plate to detect the meandering amount of the band plate, and the meandering adjustment roll is inclined in a plane substantially parallel to the output side band plate according to the detected meandering amount. Or, it is a method of inclining three-dimensionally.

However, as a result of applying such a method to the pinch rolls 4 and 4 shown in FIG. 1, not only the meandering cannot be corrected sufficiently, but also the meandering correction delay occurs due to the poor response of the meandering correction. Moreover, since it is not a method for preventing the meandering, the problem caused by the meandering cannot be sufficiently solved.

On the other hand, as a method for preventing the occurrence of meandering,
In the cold rolling, the strength of the rolled material and the rolling mill entry, the method of determining the meandering occurrence limit curve in the relationship between the tension difference of the plate on the exit side, the method of setting the tension difference so as to be less than this meandering occurrence limit curve, for example, It is known from JP-A-64-48617.

[0008]

In this method, the tension difference between the rolling mill input and output sides in cold rolling is about 0.1 to 0.5 N.
/ Mm ^2, and if such a large tension is applied between the pinch roll and the rolling mill, a large meandering will occur on the pinch roll exit side, and the high temperature strip-shaped slab will be stretched and deformed and the width Warpage and width reduction occurred. Then, this invention makes it a subject to prevent the meandering of the thin strip-shaped cast piece continuously cast and conveyed to a winder, and to perform rolling etc. stably.

[0009]

In order to solve the above-mentioned problems, a method of transporting a strip-shaped slab according to the present invention is a winding machine that transports a strip-shaped slab continuously cast using a cooling drum on a transport line. In the production of the strip-shaped slab that is wound into a coil by means of the above, the i-th facility Si with the cooling drum as the starting point S ₀ is installed in the transport line where the n-group facility S that applies a rolling force to the strip-shaped slab is installed. A tension adjusting device Bi is installed between the equipment and the equipment Si-1, and the balance between the output side tension Ti of the equipment Si-1 and the entrance side tension Tii of the equipment Si is adjusted to convey the thin strip slab. Is characterized by.

[0010]

FIG. 2 shows the gripping point Gp (casting) of the strip-shaped cast piece S in the pinch roll 4 when the strip-shaped cast piece S continuously cast by using the cooling drum is fed in the direction of the arrow L by the pinch roll 4. The center of the load between the strip and the roll) and the center of tension in the width direction of the thin strip-shaped cast slab S are shown.

If there is unevenness in the shape, thickness or temperature in the width direction of the strip slab S that passes through the pinch roll 4, and if the rolling force in the width of the slab in the pinch roll 4 is uneven, the thin strip slab will be thin. Stripping slab S gripping point G
A deviation V (hereinafter, turning arm length v) occurs between p and the tension center Tp in the width direction of the thin strip slab S.

As a result, in the thin strip-shaped slab S, the swing arm length v shown in the equation (1) and the line tension difference (T _i -T) between the inlet side and the outlet side are shown.
_The turning force M (in the plane of the slab) obtained by the product of ( ₀ ) causes the skid to slip about the gripping point Gp as a broken line. As a result, the direction L ₀ of feeding the strip-shaped slab S of the pinch roll 4 and the longitudinal direction L ₁ of the strip-shaped slab S after turning do not coincide with each other, so that L ₁ and L ₀ of the strip-shaped slab S are different from each other. Shift to the WS side (working side) so that they match.
At this time, the lateral slip of the thin strip-shaped cast slab S due to the turning arm length v causes the tension T on the outlet side to be greater than the tension T ₀ on the inlet side of the pinch roll.
_The larger _i is, the more likely it is to occur. M = (T _i −T ₀ ) / v (1) where T _{0 is the} tension on the pinch roll entrance side, T _{i is the} tension on the pinch roll exit side, and T ₀ <T _i .

Therefore, in order to prevent the strip-shaped slab from meandering in the pinch roll, it is necessary to suppress the outlet line tension T _i according to the inlet line tension T ₀ of the pinch roll.

FIG. 3 uses the continuous casting apparatus shown in FIG.
Thickness of 1.0-10 mm, width 700 and 1
A 400 mm thin strip slab is conveyed by the pinch roll 4.
As the pinch roll 4 and tension adjusting device 7
Bridle roll 7₁, 7 ₂Between, i.e. pinch low
Slab tension Ui (N / mm²) And pinch low
The relationship between the slab meandering amount (mm) in Rule 4 is shown. What
The slab tension between the pinch roll 4 and the cooling drum 1
U₀(N / mm²) Exceeds 0.01, the slab will cool
Since it fractures immediately after the slab, tension is applied to the slab.
Not.

In FIG. 3, when the slab tension Ui at the pinch roll exit side exceeds 0.05 N / mm ² , the slab meandering amount is 20.
When the rolling is performed on the pinch roll exit side, the thickness of the slab is severely damaged by a sharp increase of more than mm, and the rolling accuracy becomes unstable, for example, the accuracy of the plate thickness deteriorates. Therefore, in order to suppress the meandering amount of the slab to 20 mm or less and to perform the rolling stably, the slab tension Ui on the exit side of the pinch roll is 0.0
It should be 5 N / mm ² or less.

FIG. 5 shows a state in which, when the strip-shaped slab S continuously cast using the cooling drum is rolled by the rolling mill 5, the strip-shaped slab S meanders to the WS side. The line tension Tii on the rolling mill entrance side is decomposed into a force (Tii · cos θ) parallel to the line direction L and a force (Tii · sin θ) perpendicular to the line direction L. The force (Tii · sin θ) in the direction perpendicular to the line direction L is
It acts as a force for returning the thin strip slab S to the DS side (driving side), that is, a meandering restoring force (self-centering force). This meandering restoring force (Tii · sin θ) is the line tension Ti.
It increases as i increases.

Since the actual line tension Tii has a certain fluctuation range, it may momentarily become extremely low. At that time, slack, flapping, twisting, etc. occur in the thin strip slab S, which causes meandering. Will be promoted.
Therefore, in order to prevent the meandering of the strip slab S in the rolling mill 5, it is necessary to increase the line tension Tii on the rolling mill entrance side to a certain value or more.

FIG. 6 shows a plate thickness of 1.0 to 10 mm and a width of 700 and 1 cast by using the continuous casting apparatus shown in FIG.
When a 400 mm thin strip slab is conveyed to the rolling mill 5 by the pinch roll 4 and the tension adjusting device 7, the slab tension Uii (N / mm ² ) between the tension adjusting device 7 and the rolling mill 5, that is, on the rolling mill entrance side. And the relationship between the meandering amount of the slab in the rolling mill 5 are shown.

In the drawing, the slab tension Uii on the inlet side of the rolling mill is shown.
Is less than 0.05 N / mm ² , the slab meandering amount is 20 mm
And the end of the slab is severely damaged, and the strip-shaped slab loosens, flaps, and twists on the inlet side of the rolling mill, which makes the rolling unstable. On the other hand, the slab tension Ui
When i is 0.05 N / mm ² or more, the meandering amount of the slab can be 20 mm or less, which is not a problem in rolling, winding, and the next step after winding.

The slab tension Uii on the rolling mill entrance side is set to 0.15N.
The meandering prevention effect is saturated even if it exceeds / mm ^2, and the thin strip slab may cause width reduction or width warp due to plastic deformation, and the equipment cost for applying large tension is high. There is a problem that it is bulky and that the thin strip slab is cooled and cannot be heat-treated at a required temperature. Therefore, the upper limit is 0.
15 N / mm ² .

[0021]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 4 shows an example of a device for carrying out the present invention. The thin strip slab S cast by the cooling drum 1 (corresponding to S ₀ ) is driven to rotate by the pinch roll 4 (Si-1).
And the rolling mill 5 (corresponding to Si) in the direction of the arrow. The pinch roll 4 applies a hydraulic pressure to the strip-shaped slab S and suppresses the current value of a motor (not shown) directly connected to the shaft of the pinch roll 4 to generate a predetermined braking force, and the pinch roll 4
The line tension between the tension adjusting device 7 (corresponding to Bi) can be adjusted. Bridle rolls 7-1, 7-
Disc type brake devices 8-1, 8-2 are provided on the second shaft.
In the brake devices 8-1 and 8-2, the air pressure supplied from the compressor (not shown) can be adjusted by the adjusting valve 9. The line tension Ti of the pinch roll 4 and the tension adjusting device 7 is adjusted to a predetermined value by the electric current value of the motor, and the line tension Tii between the tension adjusting device 7 and the rolling mill 5 is the bridle roll 7-
It is adjusted to a predetermined value by the braking force of 1, 7-2.
In the arithmetic and control unit 10, the line tension Ti on the exit side of the pinch roll and the line tension Tii on the entrance side of the rolling mill are calculated by the equation (2). T = U × W × G (2) where T: line tension Ti or Tii (N / mm ² ) U: slab tension Ui or Uii (N / mm ² ) W: slab width ( mm) G: Cast piece thickness (drum gap) (mm)

Further, the motor current of the pinch roll is adjusted so that the line tension Ti calculated by the equation (2) becomes a predetermined value, and the air pressure to the brake device 8 is adjusted so that the line tension Tii becomes a predetermined value. To be done. The air pressure P supplied to the brake device 8 is calculated by the equation (3). P = (T−b) / a = (U × W × G−b) / a (3) where P: air pressure (N / mm ² ) T: line tension Ti or Tii (N / mm ² ) U: Slab tension Ui or Uii (N / mm ² ) W: Slab width (mm) G: Slab thickness (drum gap) (mm) a: Equipment-specific constant b: Equipment-specific constant

The tension Tii and the air pressure in the above equation (2) and the constants a and b peculiar to the equipment in the above equation (3) are determined as follows, for example. In FIG. 4, the strip-shaped slab S is sandwiched between the pinch rolls 4 and 4 by the pressing force when the strip-shaped slab S is conveyed, and the bridle rolls 7-1 and 7-2 are inserted.
Air is supplied to the air cylinders (not shown) of the brake devices 8-1 and 8-2 in a state where the bridle rolls 7-1 and 7-2 are braked, and the tip of the thin strip-shaped slab S is passed. Is pulled in the transport direction via a load cell (not shown). At this time, the load when the strip-shaped slab starts to move is measured for each size of the strip-shaped slab. The measured values are plotted to determine the relationship between the air pressure P and the value of the load meter, that is, the line tension Tii on the rolling mill entrance side as shown in FIG. From the slope a and the intercept b in this figure, the constants a and b peculiar to the equipment are obtained. The constants a and b in the examples were 214 and 572, respectively. Similarly, the line tension Ti on the pinch roll exit side is obtained in the same manner as above, and the relationship between the current value of the pinch roll drive motor and the value measured by the load cell, that is, the line tension Ti on the pinch roll exit side is determined, and the air pressure and the line are determined. Tension Ti
It is stored in the arithmetic and control unit 10 together with the relationship with i.

Between the cooling drum 1 and the pinch roll 4,
A loop guide 12 and a dansential roll 11 for preventing flapping of the thin strip slab S are installed. Further, in front of the pinch rolls 4 and 4 and the rolling mill 5, a support roll 13 and a pressing roll 14 for suppressing the meandering of the thin strip-shaped slab S due to slack, flapping, and twisting are installed. In order to tightly wind the strip-shaped cast slab S around the winder 6, a looper device 15 and a deflector roll 16 for controlling the slab tension in front of the winder are installed in the rear of the.

Next, the conveyance of the strip-shaped cast piece by this apparatus will be described. During casting, a tail end (upper end) of a dummy sheet (not shown) is sandwiched between the cooling drums 1 and 1, and the tip end of the dummy sheet is wound around the winder 6. The slab tension after the start of casting is reduced until the joint between the dummy sheet and the thin strip slab S reaches the pinch roll 4 to prevent the slab from breaking. Next is the looper 15
After reaching the temperature, the joint is wound to a medium degree, and after being wound on the winder 6, it is increased to prevent loosening, flapping, twisting, etc. of the thin strip slab S during rolling.

In the arithmetic and control unit 10 shown in FIG. 4, the outlet slab tension Ui of the pinch roll 4 and the inlet slab tension Ui of the rolling mill 5 are set.
i and the slab size, the line tension T is calculated by the equation (2).
i and Tii are calculated, and the motor current of the pinch roll 4 is adjusted based on the relationship between the line tension Ti and the motor current value of the pinch roll 4. Further, the air pressure P is calculated by the equation (3) using the constants a and b peculiar to the equipment. The air pressure adjusting valve 9 is adjusted by the calculated control signal of the air pressure P, so that the braking device 8-1,
The air pressure supplied to the air cylinder 8-2 is adjusted, the braking force of the brake device 8 is adjusted, and the slab tension Ui on the outlet side of the pinch roll 4 and the inlet side of the rolling mill 5 is adjusted.
Uii is adjusted.

In the above embodiment, when changing the thickness of the slab during casting, the position detector 18 is provided close to the drum driving cylinder 17 connected to the shaft of the cooling drum 1.
The signal of the drum gap from the position detector 18 is input to the arithmetic and control unit 10 as a slab thickness to calculate the equations (2) and (3) to correct the line tension T and the air pressure P.

The strip-shaped slab to which the present invention is applied is
Also applicable to other steels such as stainless steel and plain steel.
Further, the example of the bridle roll is shown as the tension adjusting device 7, but instead of this, a pinch roll or a dancer roll with a weight that can apply a braking force may be used.

An example in which SUS304 stainless steel is continuously cast into a strip-shaped slab by using the apparatus shown in FIG. 4 and hot rolling is performed subsequent to the casting will be described. Table 1 shows the dimensions, tension and meandering amount of the strip-shaped cast piece. In the example of the present invention, the meandering amount of the slab on the pinch roll exit side and the rolling mill entrance side was 20 mm or less, and there was no flaw on the end of the slab due to meandering, and stable conveyance and rolling could be performed.

On the other hand, in Comparative Example No. 9-11,1
In Nos. 3 and 15, since the slab tension on the pinch roll exit side was excessive, meandering on the pinch roll was likely to occur, and the slab collided with the guide and cracked on both end faces of the slab. In addition, No. of the comparative example. In Nos. 10 and 12 to 14, since the slab tension on the inlet side of the rolling mill was small, meandering in the rolling mill was likely to occur, and similarly cracks occurred on both end faces of the slab. Comparative Example N
o. In No. 16, the slab tension on the inlet side of the rolling mill was too large, so that the width of the slab decreased and warpage occurred.

[0031]

[Table 1]

[0032]

According to the present invention, when the thin strip-shaped slab continuously cast using the cooling drum is conveyed, the slab tension on the outlet side of the pinch roll and the inlet side of the rolling mill is adjusted to an appropriate range. As a result, it is possible to prevent the thin strip-shaped slab from meandering. As a result, it is possible to prevent flaws and cracks at both ends of the slab due to meandering, and to prevent the plate from passing, and to stably roll the strip-shaped slab and wind it in an orderly manner.

[Brief description of drawings]

FIG. 1 is a perspective view showing an outline of a twin-drum type continuous casting device.

FIG. 2 is a plan view showing a meandering state of a thin strip-shaped cast piece in a pinch roll.

FIG. 3 is a diagram showing the relationship between the tension and the amount of meandering of a thin strip in a pinch roll.

FIG. 4 is a front view showing the outline of an apparatus for carrying out the present invention.

FIG. 5 is a plan view showing a meandering state of a thin strip-shaped cast piece in a rolling mill.

FIG. 6 is a diagram showing the relationship between the tension and the amount of meandering of a thin strip slab in a rolling mill.

FIG. 7 is a diagram showing a relationship between an air pressure supplied to a brake device and a slab tension generated by the air pressure.

[Explanation of symbols]

 1 ... Cooling drum 2 ... Side weir 3 ... Hot water pool part 4 ... Pinch roll 5 ... Rolling machine 6 ... Winding machine 7 ... Tension adjusting device (bridle roll) 8 ... Bridle roll brake 9 ... Air pressure adjusting valve 10 ... Calculation Control device 11 ... Tangent roll 12 ... Loop guide 13 ... Support roll 14 ... Press roll 15 ... Looper device 16 ... Deflector roll 17 ... Drum drive cylinder 18 ... Position detector S ... Thin cast piece

Claims (3)

[Claims] 1. In the production of a thin strip-shaped cast piece, which is continuously cast using a cooling drum, is conveyed on a conveying line and is wound into a coil by a winding machine, the strip-shaped strip is rolled down. The i-th facility Si with the cooling drum as the starting point S0 is installed in the transfer line where the n facilities S that apply force are installed.
A tension adjusting device Bi is installed between the equipment Si-1 and the equipment Si, and the output side tension Ti of the equipment Si-1 and the equipment Si are installed.
The method for transporting a thin strip-shaped slab, wherein the thin strip-shaped slab is transported by adjusting the balance of the inlet side tension Tii. 2. A cooling drum in the production of a thin strip-shaped slab that is continuously cast using a pair of rotating cooling drums, is transported on a transport line, and is wound into a coil by a winder. At least a pinch roll, a tension adjusting device and a rolling mill are sequentially arranged on the rear surface side, and a braking force according to the cross-sectional dimension of the thin strip slab is applied to the shaft of the pinch roll and the tension adjusting device. A method for conveying thin strip slabs. 3. A cooling drum in the production of a thin strip-shaped slab that is continuously cast using a pair of rotating cooling drums, is transported on a transport line, and is wound into a coil by a winder. At least a pinch roll, a tension adjusting device and a rolling mill are arranged in this order on the rear surface side, and the slab tension on the outlet side of the pinch roll is maintained at 0.05 (N / mm ² ) or less, Side slab tension is 0.05
A method for transporting thin strip-shaped slabs, characterized in that the thickness is maintained at 0.15 (N / mm ² ).