JP3366106B2 - Continuous annealing device for steel strip and its tension control device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention prevents the production of heat buckles, scratches and walks on steel strips in a continuous process line for producing soft steel strips for drawing work, etc. to improve productivity and quality. The present invention relates to a continuous annealing device and a tension control device used for the continuous annealing device.

[0002]

2. Description of the Related Art A steel strip such as a thin steel plate is passed through a continuous process line for various treatments. There are various treatments such as annealing, pickling, and plating. These treatments are performed by a continuous annealing line, a continuous pickling line, a continuous plating line, or the like. At the time of threading, the steel strip wound on the coil is unwound at the entrance side of the line with a pay-off reel and welded to the rear end of the preceding steel strip, and at the exit side is wound into a coil with a tension reel to form the welded part. The work of cutting and winding the trailing steel strip around the tension reel is performed.

In such a continuous process line,
Even when welding at the entrance side and cutting at the exit side,
Since it is necessary to pass processing equipment such as annealing equipment at a predetermined constant speed for the steel strip, a looper is provided between the processing equipment and the entrance equipment and between the exit equipment to adjust the speed. In addition, when the plate thickness or width of the steel strip coil to be processed changes, or when the metal composition such as steel type changes, it is necessary to change the strip running speed in the processing equipment, including the equipment on the input and output sides. The speed is adjusted.

Particularly, a soft steel strip for drawing or for a soft tin plate is manufactured by cold rolling and then annealing and overaging in a continuous annealing furnace. This continuous annealing furnace is a heating zone for heating a steel strip to a predetermined temperature, a soaking zone for annealing, a primary cooling zone for performing overaging treatment,
It is a long facility with an overaging zone and a secondary cooling zone.
Generally, in a process line such as a steel strip, bridle rolls are provided on the inlet side and the outlet side of the line to apply an appropriate tension to the steel strip and the like to perform stable striping. At this time, if the tension is insufficient, the steel strip will meander and come into contact with equipment such as the furnace wall, causing scratches on the steel strip.If the tension is excessive, squeezing in the lengthwise direction of the steel strip called a heat buckle will occur. I have a problem.

Since the continuous annealing furnace for steel strips is long, it is difficult to apply proper tension to the steel strips over the entire length of the furnace only by the bridle rolls before and after the furnace, and the bridle rolls are also provided in the furnace. It is known from Japanese Utility Model Application Laid-Open No. 139707/1975 that the tension is controlled by the method. That is, as shown in FIG. 11, the steel strip S includes the entrance side bridle roll 1 and the exit side bridle roll 2 provided before and after the continuous annealing furnace F, as well as between the heating zone 4 and the retention zone 5 and the retention zone 5. And cooling zone 6 (it is stated that an overaging zone may be provided)
An in-furnace bridle roll 3 is provided between them to adjust the tension of the steel strip S.

In Japanese Patent Publication No. 60-7693, bridle rolls are provided on the outlet side of the heating zone and the outlet side of the soaking zone,
To increase the tension in the heating zone where the steel strip thermally expands, and to reduce the tension in the heating zone exit side and the soaking zone after the steel strip softens,
It is also disclosed that bridle rolls are provided on the inlet side and the outlet side of the primary cooling zone to reduce the tension in the primary cooling zone which is likely to cause shape deformation such as a cooling buckle due to rapid cooling.

In JP-A-1-162727, as shown in FIG. 12, a plurality of bridle rolls are divided into two groups (7A and 7B and 8A and 8B), and a dancer roll 10 is provided between them. A tension control device has been proposed which absorbs tension fluctuations that fluctuate instantaneously at a high frequency, which cannot be absorbed only by a bridle roll, by the vertical movement of the dancer roll 10, and the control method is disclosed in JP-A-1-165726. Proposed. In the technique of both publications, the dancer roll 10 lifts the steel strip S upward between the deflector roll 9C and the second bridle roll 8A,
It is balanced by a rope 11 with a weight 12 via a drum 13. Reference numeral 14 is a motor for rotating the drum 13 with a constant torque.

Further, in Japanese Patent Laid-Open No. 5-43099, a strip is passed between a transport roll and a movable transport roll,
In a device that controls the tension of the strip by moving the movable transport roll, it is directly connected to the support shaft and an arm that pivots around the support shaft and has a movable transport roll at the end opposite to the support shaft, and is supported by the arm. An electric motor for generating a torque around the shaft to apply tension to the strip, an angle detector for detecting the angle of pivotal movement of the arm, a tensiometer for detecting the tension of the strip, a detection angle and a detected tension. Describes a tension control device that corrects the torque generated in the arm to control the strip tension to a target tension.

The main part of the apparatus disclosed in the above-mentioned Japanese Patent Laid-Open No. 5-43099 is shown in FIG. 13. In FIG. 13, what is referred to as a transport roll in the above publication is a deflector roll 9 and also a movable transport roll. There are dancer rolls 10 which are adjacent to the bridle rolls 8. The dancer rolls 10 are rotatably supported by the arms 16 and the arms 16 are pivoted about the support shafts 15 so that the dancers The roll 10 is moved up and down. Dancer roll 10
By moving up and down with such a mechanism, mechanical resistance is smaller than that of a dancer roll as shown in FIG. 12, and movement with low inertia is possible, and high responsiveness to a sudden tension change from the outside. It is described that highly accurate tension control is possible.

In FIG. 13, reference numeral 18 is a torque motor for turning the support shaft 15, and 19 is an angle detector for detecting the turning angle of the arm 16. Also, 17 is a support shaft 15 on the arm 16.
A counterweight provided on the arm 16 to generate a torque centering on the
, 21 is a counterweight position detector, and these are installed as necessary. It is said that by adjusting the position of the counter weight 17, the torque generated in the arm 16 can be controlled, and the torque motor 18 can be downsized.

However, when passing a thin steel strip at a high speed, there is a high-frequency tension fluctuation, and the dancer roll 10 as shown in FIG. 12 can absorb it due to the large inertia of its mechanical system. could not. Further, in the dancer roll of the arm rotation type as shown in FIG. 13, the mechanical system has a low inertia, and it is possible to absorb high-frequency tension fluctuations up to a certain degree, but to install the dancer roll, a considerable space is required in terms of equipment. In particular, when the existing line is modified, there is a problem that it cannot be installed at the most suitable position.

In particular, in a continuous annealing furnace for steel strips having a heating zone, a soaking zone, a primary cooling zone, an overaging zone and a secondary cooling zone,
When the gas jet cooler cools the steel strip in the secondary cooling zone, scratches may occur on the surface of the steel strip, and rolling of the steel strip called a walk may occur in the subsequent water cooling tank. there were. Problems such as scratches and walks,
Although it was resolved by increasing the tension in the furnace by the bridle rolls on the inlet and outlet sides of the continuous annealing furnace, heat buckles occurred in the overaging zone. Even if the bridle roll is provided in the furnace, no effect is obtained at the positions specifically disclosed in the above-mentioned publications. Therefore, in the conventional apparatus, the operation of suppressing the strip running speed of the steel strip was forced.

[0013]

SUMMARY OF THE INVENTION According to the present invention, in a continuous process line for steel strips, when a thin steel strip is passed at high speed, even if there is a high-frequency tension fluctuation on the inlet side and the outlet side. It is possible to control the tension so that it will not be transmitted to processing equipment such as annealing equipment, and it is possible to perform stable striping under appropriate tension, and buckling of steel strips, width shrinkage, and scratches due to meandering and loosening It is an object of the present invention to provide a compact tension control device capable of reliably preventing such problems and easily installed in an existing line.

Further, according to the present invention, in a continuous annealing furnace for a steel strip having a heating zone, a soaking zone, a primary cooling zone, an overaging zone and a secondary cooling zone, heat buckles, scratches and walks of the steel strip are generated. The purpose is to reliably prevent and improve quality under high productivity.

[0015]

The present invention is intended to solve the above-mentioned problems, and its gist is as follows. (1) In a continuous annealing furnace for a steel strip having a heating zone, a soaking zone, a primary cooling zone, an overaging zone, and a secondary cooling zone, the continuous annealing furnace
Outside the furnace bridle rolls are installed on the inlet and / or outlet side of the
At the same time, the in-furnace bridle roll is provided between the overaging zone and the secondary cooling zone, and
Steel strip back in heating zone, soaking zone, primary cooling zone, overaging zone
Reduce the tension of the steel strip to a range that avoids ring and width shrinkage, and use the secondary cooling zone on the exit side of the bridle roll in the furnace to make the steel strip snake
A continuous annealing device for steel strips, which is characterized by increasing the tension of steel strips in a range that avoids rolling and loosening .

[0016] (2) In the tension controller of the steel strip placed immediately entry side and / or immediate delivery side of your Keru <br/> processing equipment in a continuous process line of the steel strip, a first bridle roll, a The inclination angle θ in the traveling direction of the steel strip between the two bridle rolls is 0 ° <θ <90 °.
And a buffer roll that abuts the steel strip in a range, the buffer roll being capable of turning in a direction intersecting a path line connecting the rolls before and after the buffer roll in accordance with a change in tension of the steel strip, and A tension control device for a steel strip, characterized in that the tension α of the steel strip is adjusted by controlling an angle α formed between an arm of the buffer roll and a pass line.

(3) The angle α formed by the arm of the buffer roll and the pass line is 0 ° <α ≦ α ₀ or α with the boundary α ₀ at which F has the maximum value as expressed by the following equation (1). ₀ ≤ α <
The tension control device for a steel strip according to (2), wherein the tension of the steel strip is adjusted with an angle of 90 ° as a control range.

[0018]

[Equation 2] A: Buffer roll fulcrum b: Distance between pass line and fulcrum c: Distance between fulcrum and second bridle roll entry side roll α: Angle between buffer roll arm and pass line R: Buffer roll arm length a: No. Distance between the first bridle roll exit side roll (or deflector roll) and the second bridle roll entrance side roll (or deflector roll) T _M : plate tension F: force with which the buffer roll is pressed by the plate tension T _M

[0019]

(4) The shaft of the buffer roll is rotatably supported by an arm fixed to a support shaft, and a torque motor for rotating the support shaft is provided. (2) or (3) Tension control device. (5) The steel strip tension control device according to (4), wherein a counterweight is provided on the support shaft. (6) The bridle roll outside the furnace is the same as in (2) to (5).
Characterized by being a tension control device for steel strips according to any one of
The continuous annealing apparatus for a steel strip according to (1).

The present invention will be described in detail below with reference to the accompanying drawings. The first technical feature of the present invention is, as shown in FIG. 1, a heating zone 22, a soaking zone 23, a primary cooling zone 24, an overaging zone 2
5. In the continuous annealing furnace F for the steel strip having the secondary cooling zone 26, the bridle roll 3 in the furnace is provided between the overaging zone 25 and the secondary cooling zone 26. Further, a second technical feature is, in a continuous process line for steel strips, as shown in FIG. 2, a first bridle roll, a second bridle roll, and a buffer roll that is in contact with the steel strip between the two bridle rolls. And the buffer roll is capable of swiveling in a direction intersecting with a pass line connecting the rolls before and after the buffer roll according to the tension variation of the steel strip, and the angle α formed by the arm of the buffer roll and the pass line is as follows. F as expressed by equation (1)
With α ₀ indicating the maximum value as a boundary, 0 ° <α ≦ α ₀ or α
A tension control device for a steel strip is characterized in that the tension of the steel strip is adjusted with an angle of ₀ ≦ α <90 ° as a control range.

[0022]

[Equation 3] A: Buffer roll fulcrum b: Distance between pass line and fulcrum c: Distance between fulcrum and second bridle roll entry side roll α: Angle between buffer roll arm and pass line R: Buffer roll arm length a: No. Distance between the first bridle roll exit side roll (or deflector roll) and the second bridle roll entrance side roll (or deflector roll) T _M : plate tension F: force with which the buffer roll is pressed by the plate tension T _M First feature The points will be described below.

In FIG. 1, the cold rolled steel strip S is
From a pay-off reel (not shown), a cleaning device, an entrance looper, etc., an entrance bridle roll 1, and a continuous annealing furnace F.
to go into. In the continuous annealing furnace F, it is heated to a predetermined temperature in the heating zone 22, is annealed by being soaked to the annealing temperature for a predetermined time in the soaking zone 23, is cooled in the primary cooling zone 24, and is then overaged in the overaging zone 25. It is treated and then cooled in the secondary cooling zone 26 and the water cooling tank 28 to obtain a steel strip having desired workability such as drawability. In the secondary cooling zone 26, the steel strip is a gas jet cooler 27.
Is cooled at an appropriate cooling rate. After that, it is dried by a dryer 29 and cooled by a final cooling zone 30 to a temperature at which temper rolling can be performed. Then, the bridle roll 2 on the delivery side, a temper rolling mill (not shown) and the like are taken up and wound on a tension reel. In some lines, the temper rolling mill is not installed inline, in which case the final cooling zone 30 does not necessarily have to be installed.

Each of the bridle rolls 1, 2 and 3 is constructed by arranging a plurality of rolls so that the friction coefficient of the surface is large and the contact area with the steel strip S is large. In the apparatus of the present invention, the steel strip S in the heating zone 22, the soaking zone 23, the primary cooling zone 24 and the overaging zone 25 is first adjusted by adjusting the peripheral speed difference between the inlet side bridle roll 1 and the in-furnace bridle roll 3.
Adjust the tension of. Then, the peripheral speed difference between the bridle roll 3 in the furnace and the bridle roll 2 on the outlet side is adjusted to adjust the secondary cooling zone.
Adjust the tension in 26 and the water cooling tank 28.

In order to manufacture a thin steel sheet having excellent workability such as drawability, it is necessary to gradually cool the steel strip after overaging treatment at an appropriate cooling rate, and a defective shape such as a cooling buckle occurs. To prevent this, the gas jet cooler 27 performs relatively gentle cooling in the secondary cooling zone 26, and then rapidly cools it in the water cooling tank 28 which is an economical cooling facility.
In the conventional apparatus, when the steel strip S is thin and wide, in the secondary cooling zone 26, the strong wind of the gas jet cooler 27 causes the steel strip S to vibrate greatly and contact the cooler 27 as described above. Scratches were generated, and a walk of the steel strip S was easily generated in the water cooling tank 28 due to the hydroplaning phenomenon. If the tension in the continuous annealing furnace F is increased as a countermeasure against these, there is a problem that a heat buckle is likely to occur in the steel strip S in the overaging zone 25 where the steel strip temperature is relatively high.

In the device of the present invention, the overaging zone 25 and the secondary cooling zone
Since the in-furnace bridle roll 3 is provided between 26, tensions before and after the bridle roll 3 can be adjusted independently.
That is, as shown in the tension distribution of FIG. 1, the tension in the secondary cooling zone 26 and the water cooling tank 28 can be increased to an appropriate value without increasing the tension in the overaging zone 25.
Therefore, it is possible to reliably prevent the occurrence of scratches in the secondary cooling zone 26 and the walk in the water cooling tank 28 without generating a heat buckle in the overaging zone 25.

In the apparatus of the present invention shown in FIG. 1, the heating zone is
When the tension of the steel strip S in 22, the soaking zone 23, the primary cooling zone 24 and the overaging zone 25 fluctuates, the tension can be adjusted by moving the entrance side dancer roll 31 up and down. Fluctuations in tension are due to the inlet bridle roll 1 and the furnace bridle roll 3
A roll between them, for example, 32 is detected as a tension detection roll, and this is fed back to the torque command of the drive motor of the entrance dancer roll 31. After the entrance-side dancer roll 31 is moved up and down, the entrance-side dancer roll 31 is returned to its original position while adjusting the peripheral speed of the entrance-side bridle roll 1 so as not to change the tension in the furnace.

When the tension of the steel strip S in the secondary cooling zone 26 and the water cooling tank 28 changes, the tension can be adjusted by moving the exit dancer roll 34 in front of the exit bridle roll 2 up and down. . Tension fluctuation is detected by the tension detection roll.
It can be detected by 33 etc., and after the exit dancer roll 34 is moved up and down, the exit dancer roll 34 is adjusted while adjusting the peripheral speed of the exit bridle roll 2 so as not to change the tension.
To the original position.

Further, tension detectors 35 and 36 are provided in the overaging zone 25 and the secondary cooling zone 26, respectively, to measure the tension, and these are fed back to drive the bridle roll 3 in the furnace and the bridle roll 2 on the outlet side. It is also effective to do. Next, the tension control device for the steel strip, which is the second technical feature of the present invention, will be described below.

As shown in the example of FIG. 2, the apparatus of the present invention is provided with first bridle rolls 7A and 7B, second bridle rolls 8A and 8B, and a buffer roll 37. The buffer roll 37 abuts on the steel strip S between the first bridle rolls 7A and 7B and the second bridle rolls 8A and 8B, and rolls before and after the buffer roll 37 (according to the tension variation of the steel strip S). In FIG. 2, the second roll 7B of the first bridle roll and the first roll 8A of the second bridle roll can be swiveled in a direction intersecting with a pass line L (direction of an arrow) and a buffer roll. As an angle α formed between the arm and the pass line of 0 ° <α ≦ α ₀ or α ₀ ≦ with respect to α ₀ at which F has a maximum value as expressed by the following equation (1) from the relationship of FIG. The tension of the steel strip is adjusted with an angle of α <90 ° as a control range.

[0031]

[Equation 4] A: Buffer roll fulcrum b: Distance between pass line and fulcrum c: Distance between fulcrum and second bridle roll entry side roll α: Angle between buffer roll arm and pass line R: Buffer roll arm length a: No. Distance between the first bridle roll exit side roll (or deflector roll) and the second bridle roll entrance side roll (or deflector roll) T _M : plate tension F: force with which the buffer roll is pressed by the plate tension T _M α and F in FIG. Shows the relationship. T _M , a, b, c, and R are determined by the installation conditions, and F is α ₀ showing the maximum value F _max.
Have.

The above equation (1) is an upwardly convex graph having α ₀ as the maximum point. Since F increases / decreases around α _0, it is desirable that the control be performed within a range of 0 ° <α ≦ α ₀ or α ₀ ≦ α <90 °. Furthermore, considering mechanical equipment conditions, it is more desirable that α be 0 ° <α ≦ α ₀ . However, in reality, as will be described later, F = T _M cos
Since the correction is performed by the expression α (sin θ ₁ + sin θ ₂ ), there is no problem even if it is used in the range of 0 ° <α <90 °. The inclination angle θ differs depending on the moving position of the buffer roll 37 on the inlet side and the outlet side. As shown, the inlet side is θ ₁ and the outlet side is θ ₂ .

The moving range of the buffer roll 37 in the apparatus of the present invention is designed in this way, and the hollow lightweight roll is used to achieve extremely low inertia, and the conventional dancer roll as shown in FIGS. It can move more sensitively to tension fluctuations than 10. Therefore, the steel strip S on the inlet side or the outlet side of the device of the present invention is
Even if the tension of the abruptly changes in a high frequency, the buffer roll 37 can absorb it.

The example of FIG. 2 illustrates a preferred embodiment of the present invention in which the buffer roll 37 is a hollow roll and the arm 16
Is rotatably supported by the arm 16, and the arm 16 is fixed to the support shaft 15. The support shaft 15 is rotatably supported by a pedestal or the like (not shown), and by rotating the support shaft 15 with a torque motor 18, the buffer roll 37 can be swung in a direction intersecting the pass line L.

In the present invention, the turning movement of the buffer roll 37 can be performed not only by the torque motor 18 as shown in FIG. 2 but also by hydraulic pressure or pneumatic pressure. In FIG. 2, each bridle roll 7A, 7B, 8A, 8B has a surface with a large friction coefficient and is arranged so as to increase the contact area with the steel strip S, and the drive motors 38A, 38B,
It is rotated by 39A and 39B. The buffer roll 37 is a non-driving arm so that it can rotate freely when the steel strip S passes through.
It is pivotally supported by 16.

The steel strip S is composed of the bridle rolls 7A, 7
B, 8A and 8B are rotated to pass through in the direction of the arrow, and the frictional resistance with each roll causes the tension T ₁ on the inlet side and the tension T on the outlet side.
₂ is separated. The device of the present invention comprises a first bridle roll 7A and 7B and a second bridle roll 8A and 8B.
The buffer roll 37 is brought into contact with the strip S between B,
In the example of FIG. 2, the steel strip S is pushed up above the pass line L,
Intermediate tension T _M is applied.

In this state, for example, when the entrance tension T ₁ changes to T ₁ + ΔT including the high frequency tension fluctuation ΔT, the intermediate tension T _M also tries to change to T _M + ΔT, but the buffer roll 37 uses the torque motor. Since the steel strip S is pushed up by a constant torque due to 18, and this torque is balanced with the intermediate tension T _M , the low inertia buffer roll 37 is mechanically moved by the turning movement according to the tension variation ΔT. And the intermediate tension is maintained at T _M. That is, the buffer roll 37 is
If is positive, it moves downward, and if ΔT is negative, it moves upward. Even if the inlet tension T ₁ fluctuates, the fluctuation is absorbed and the outlet tension T ₂ is not affected. Then, when the entrance side tension returns to T ₁ , the buffer roll 37 also returns to the original position. Similarly, even if the outlet tension T ₂ fluctuates, it does not affect the inlet tension T ₁ .

When the entrance tension T ₁ fluctuates to T ₁ + ΔT, the intermediate tension also fluctuates to T _M + ΔT, which is detected and the driving force of the torque motor 18 is controlled to change the angle α. It is also possible to move the buffer roll up and down electrically for absorption. Even if there is a high-frequency tension change that cannot be followed by this control, the buffer roll 37 pushing up the steel strip with a torque balanced with T _M mechanically moves up and down to absorb the change. You can

In the apparatus of the present invention, the buffer roll 37 is provided with
An upward torque is applied by the constant driving force of the torque motor 18 to push up the steel strip S, and the pushing force is controlled by the inclination angle α. Mechanically, 0 ≦ α ≦ 90
Although it is possible to control in the range of °, in the control at a certain α position, the tension set value is input, the driving force is applied to the torque motor 18, the tension at that time is detected, and the target tension value is set. I'm giving you feedback. Also, the buffer roll 37
Even if the intermediate tension T _{M is} constant, the force applied to is changed by the inclination angle α, the inclination angles θ ₁ and θ ₂ , and therefore the tension is corrected by the equation (2). Enter this F, torque motor
Set the torque of 18.

F = T _M cos α (sin θ ₁ + sin θ ₂ ) (2) F: Force pressing buffer roll 37 T _M : Tension of buffer roll 37 (intermediate tension) In the device of the present invention, the tension fluctuation of steel strip S If the speed is slow, adjust the torque of the torque motor 18 or adjust the rotational peripheral speed of the first bridle rolls 7A and 7B or the second bridle rolls 8A and 8B to the drive motor 38A.
And 38B or 39A and 39B can be used for control. In addition, the above-mentioned tension fluctuation ΔT
When the buffer roll 37 is returned to its original position after being absorbed by the buffer roll 37, the peripheral speed of the first bridle roll or the torque of the torque motor 18 is adjusted.

By installing such an apparatus of the present invention on the inlet side and / or the outlet side of the treatment equipment such as the annealing equipment in the continuous process line for steel strip, the rapid operation of the looper on the inlet side and the outlet side of the line can be increased. It is possible to always pass the strip in the processing equipment at a proper constant tension without propagating the tension fluctuations generated during deceleration or the like to the processing equipment, and it is possible to reliably prevent the occurrence of buckling or abrasion. Further, it is possible to absorb the fluctuation in tension when the sheet passing speed of the processing equipment is changed, and it is also possible to reliably prevent the occurrence of buckling or abrasion.

Next, in the present invention, the support shaft 15 of the buffer roll 37 is provided with a counterweight as shown in the example of FIG.
It is preferable to provide 17. In the example of FIG. 3, the counterweight 17 causes upward torque on the buffer roll 37,
If this is adopted in the example of FIG. 2, the driving force of the torque motor 18 can be reduced. In addition to the example of FIG. 3, the counterweight 17 can be adjusted in position and weight depending on the direction of contact of the buffer roll 37 with the strip S and the magnitude of torque.

When the apparatus of the present invention is applied to a continuous process line, it can be easily installed at the most suitable position even in a new line or an existing line. An example of its application is shown in FIGS. 4 (a) to 4 (f). Figure 4 (a)
Is provided with a deflector roll 9 between the buffer roll 37 and the first bridle roll 7B and between the second bridle roll 8A, and the winding angle of the strip S in each bridle roll is determined by the swiveling movement of the buffer roll 37. It is constant regardless of position and the bridle roll is unaffected.

However, even if the wrap angle of the bridle rolls 7B and 8A changes depending on the turning movement position of the buffer roll 37 in the case of FIG. 2 or as shown in FIG. , If the winding angle required for the bridle roll is maintained, there is no problem. Further, the buffer roll 37 presses the strip S downward as shown in FIGS. 4 (b) and 4 (c), or FIG.
As shown in FIG. 4 (d), which is suspended upward, and further as shown in FIG.
It may be pressed laterally as shown in (e) and FIG. 4 (f). It should be noted that the bridle roll is made up of two sets, and the bridle roll may be the same as the first bridle roll shown in FIG.
A, 7B, 7C may be a set of three, or may be one.

Next, the third technical feature of the present invention will be described. An example of this embodiment is shown in FIG. This is a combination of the first feature point and the second feature point described above. That is, the bridle roll 3 is provided between the overaging zone 25 and the secondary cooling zone 26 in the continuous annealing part, and the bridle roll 7 is provided on the inlet side and / or the outlet side adjacent to the outside of the furnace.
At least one set of A, 7B, 8A, and 8B are provided so as to face each other, and the buffer roll 37 described above is provided at least at one position therebetween. By doing so, since the in-furnace bridle roll 3 is provided between the overaging zone 25 and the secondary cooling zone 26, the tensions before and after that can be adjusted independently. In addition, the bridle rolls 7A, 7B, 8A, 8B and the buffer roll 37 on the inlet side and / or the outlet side can be used to control tension fluctuations that occur during rapid acceleration / deceleration during the operation of the looper on the line inlet / outlet side in the continuous annealing equipment. It is possible to pass the steel strip with an appropriate constant tension without propagating it to the steel strip.

Further description will be given below on the basis of examples of the present invention. [Example] Example 1: The apparatus of the present invention shown in FIG.
Continuous annealing was performed by passing a mild steel strip with a width of 0.26 mm and a width of 1024 mm. In the secondary cooling zone 26, the distance between the gas jet cooler 27 and the steel strip S is 150 mm, the wind speed from the gas jet cooler 27 is 30 m / sec, and the strip running speed is 500 m / min when the strip thickness is 0.24 mm, In the case of 0.26 mm, it was 430 m / min. With the bridle roll 3 in the furnace and the bridle roll 2 on the outlet side,
When changing the tension T _b of the steel strip S in the secondary cooling zone 26, the result of measuring the deflection of the steel strip S, in the larger than the tension T _a in the heating zone 22 to the overaging zone 25, FIG. 6 As shown in (a), when the difference ΔT (= T _b −T _a ) is set to 4 N / mm ² or more, the runout amount W of the steel strip S is stabilized within 100 mm and no scratches occur. Became. The heating zone 22
The tension T _a in the overaging zone 25 was 6 N / mm ² . As shown in FIG. 6B, the shake amount W is the shake amount on one side from the pass line of the steel strip S shown by the broken line.

Further, by setting ΔT to be 4 N / mm ² or more, the problem of the walk of the steel strip S was solved. This walk was generated when water entered between the steel strip S and the roll in the water cooling tank 28 and the steel strip rocked in the axial direction of the roll due to the hydroplaning phenomenon. The problem was solved because the invasion of water was suppressed by increasing it.

As described above, the steel strip S in the secondary cooling zone 26 is
Even if the tension of No. 2 was adjusted, the tension in the overaging zone 25 and in the furnace before it was kept constant, and no heat buckle was observed.

Comparative Example: In the continuous annealing furnace F shown in FIG. 1, the bridle roll 3 in the furnace was not provided, and as shown in FIG.
Two places between the upper and lower rolls for each pass of the secondary cooling zone 26,
Support rolls 40 that come into contact with the steel strip S are installed between the gas jet coolers 27 to suppress the vibration of the steel strip S. ΔT = 0
Other than that, as a result of passing the plate under the same conditions as the above-mentioned example of the present invention,
It was possible to suppress the occurrence of scratches due to contact with the gas jet cooler 27, but in that case, it was necessary to drive the support roll 40. Further, since the gas jet cooler 27 cannot be installed at the installation location of the support roll 40 and the effective cooling length is reduced as a whole, it is necessary to increase the number of passes of the secondary cooling zone 26. Therefore, the cost for mechanical equipment and electrical equipment was about three times that of the example of the present invention.

Example 2 In a continuous annealing line for cold-rolled steel strips, the apparatus of the present invention was provided on the inlet and outlet sides of the annealing equipment to control the tension. The tension control on the entrance side of the annealing equipment will be described with reference to FIG. The steel strip S passes through the first bridle rolls 7A and 7B, the deflector roll 9, the buffer roll 37, the deflector roll 9, the second bridle rolls 8A and 8B, and the deflector roll 9,
It is introduced into an annealing facility (not shown).

Each bridle roll 7A, 7B, 8A, 8
B are drive motors 38A, 38B, 39A, 39, respectively.
The steel sheet is driven by B and the buffer roll 37 is driven by the drive motor 18 to apply an appropriate tension to the steel strip. The tension detector 41 detects the intermediate tension T _M of the steel strip S and is installed near the 7B roll. In addition, the tension detector 42
Is for detecting the tension T ₂ in the annealing equipment of the steel strip S,
It is installed after the second bridle roll 8B.

The detected tension of the tension detector 42 is fed back to the target tension 56 (T ₂ ) to be applied to the steel strip S, and the tension deviation is input to the tension controller 52 and converted into a speed command to be adjusted. To be done. This converted speed command is added to the in-furnace speed reference value 57 and input to the speed controller 50 as a speed command. The speed command controls the speed of the drive motors 39A and 39B for the second bridle rolls 8A and 8B to control the tension in the annealing equipment to the target tension T ₂ .

The detected tension of the tension detector 41 is fed back to the target tension 55 ( _TM ) to be applied to the steel strip S, and the tension deviation is input to the tension controller 51 and converted into a torque command to be adjusted. To be done. This converted torque command is input to the current controller 47 as a torque command (current command). By this torque command, the drive motor 18 for the buffer roll 37 is current-controlled to control the intermediate tension of the steel strip S to the target tension T _M.

An upward torque is applied to the buffer roll 37 by the constant driving force of the torque motor 18 to push up the steel strip S, and the inclination angles θ ₁ and θ ₂ with the pass line are both about 1.
The reference position of the buffer roll 37 is set at 1 ° and the angle α formed by the path line and the arm at about 30 °. Further, the force F applied to the buffer roll 37 changes depending on the inclination angle α and the inclination angles θ ₁ and θ ₂ even if the intermediate tension T _M is constant.
Tension correction is applied according to equation (2). This F is a tension setting device
The tension controller 51 is input from 55 to set the torque of the torque motor 18.

F = T _M cos α (sin θ ₁ + sin θ ₂ ) (2) F: Force of pressing the buffer roll 37 T _M : Tension of the buffer roll 37 (intermediate tension) The inlet side tension T ₁ fluctuates to T ₁ + ΔT In this case, the intermediate tension also fluctuates to T _M + ΔT, which is detected by the tension detector 41, the driving force of the torque motor 18 is controlled, and the buffer roll is moved up and down to be absorbed. Even if high frequency tension variation as the control can not follow, that buffer roll 37 is a steel strip pushed by T _M balanced torque moves up and down,
I was able to absorb the fluctuation.

The torque motor 18 is provided with an angle detector 19, and as described above, the buffer roll is changed by the fluctuation of the entrance tension T _1.
When 37 moves up and down, the rotation angle of the torque motor 18 is detected, the rotational peripheral speeds of the first bridle rolls 7A and 7B are adjusted, and the position of the buffer roll 37 is returned to the original state. That is, the arm angle α detected using the angle detector 19 is fed back to the target position set value (target angle) 54 to obtain a deviation to be adjusted, and the position controller 53 converts the deviation into a speed command value. . The speed command value is added to the in-core speed reference 57 and input to the speed controller 49 as a speed command. The speed command controls the speed of the drive motors 38A, 38B for the first bridle rolls 7A, 7B to control the arm angle α to the target angle.

Reference numeral 57 is a furnace speed reference value, and a predetermined furnace speed is input to the speed controller 49 of the first bridle rolls 7A and 7B and the speed controller 50 of the second bridle rolls 8A and 8B. There is. In such a control method of the present invention,
The buffer roll 37 and the second roll using the tension detectors 41 and 42 against tension fluctuations from the entrance side of the first bridle roll.
A two-stage tension control system using bridle rolls 8A and 8B is constructed, and a position control system using an angle detector 19 is constructed for vertical movement of the buffer roll 37. The tension of the steel strip S can be controlled with high responsiveness and high accuracy.

The buffer roll has a low inertia,
For tension fluctuations that cannot be absorbed by the tension control system, the buffer roll mechanically moves up and down to absorb the tension fluctuations. By the way, when the effects of the tension control by the present invention and the conventional control method were compared by simulation, the following results were obtained. The condition before the analysis is the actual tension (that is, the value of the tension detector 42) at the rear bridle roll exit side when a tension fluctuation of 880 N (= 90 kgf) is applied from the front bridle roll entrance side.

[0059]

[Table 1]

From Table 1, it can be seen that the method of the present invention is the most superior to the conventional method.

[0061]

As described above, the tension control device of the present invention employs a buffer roll having an extremely low inertia, and the buffer roll may be used in a continuous process line of a steel strip such as a continuous annealing line of thin steel sheets. Therefore, even when a thin steel strip is passed at high speed, even if there is a high-frequency tension fluctuation in the equipment on the input side and the equipment on the output side, it will not be propagated to the processing equipment such as annealing, It is possible to pass the plate stably, and it is possible to reliably prevent buckling of the steel strip and occurrence of scratches and the like. Furthermore, the installation space is small, and it can be easily installed in the optimal position on the existing line.

Further, according to the apparatus of the present invention, in the continuous annealing furnace for steel strips having the heating zone, the soaking zone, the primary cooling zone, the overaging zone and the secondary cooling zone, between the overaging zone and the secondary cooling zone. By installing the bridle roll in the furnace, the tension of the steel strip before the overaging zone and after the secondary cooling zone can be adjusted independently. Therefore, heat buckle due to too high tension in the overaging zone is prevented, and scratches on the steel strip due to contact with the gas jet cooler and walks due to water intrusion in the water cooling layer are reliably prevented.

Therefore, unlike the conventional case, there is no need to reduce the strip running speed of the steel strip due to the fear of heat buckles, scratches and walks, and it is possible to improve quality while maintaining high productivity. In addition, the added bridle roll in the furnace has a simple device structure, and construction cost and maintenance cost are low.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an example of a device of the present invention.

FIG. 2 is a perspective view showing an example of the device of the present invention.

FIG. 3 is a perspective view showing another example of a buffer roll in the device of the present invention.

FIG. 4A to FIG. 4F are explanatory views showing another example of the tension control device according to the present invention.

FIG. 5 is a vertical sectional view showing an example of the device of the present invention.

FIG. 6A is a graph showing an embodiment of the device of the present invention in the tension control device according to the present invention, and FIG. 6B is an explanatory diagram of the deflection amount W of the steel strip in the embodiment of the present invention. Is.

FIG. 7 is a vertical cross-sectional view showing a device of a comparative example.

FIG. 8 is a control system diagram in the embodiment of the present invention.

FIG. 9 is an explanatory diagram of tension control of the buffer roll of the present invention.

FIG. 10 is a diagram showing the relationship between the arm angle and the tension of the buffer roll of the present invention.

FIG. 11 is a vertical cross-sectional view showing an example of a conventional device.

FIG. 12 is an explanatory diagram showing an example of a conventional device.

FIG. 13 is an explanatory diagram showing an example of another conventional device.

[Explanation of symbols]

1 ... Inlet bridle roll 2 ... Outgoing bridle roll 3 ... Furnace bridle roll 4 ... Heating zone 5 ... Restoration zone 6 ... Cooling zones 7A, 7B, 7C ... 1st bridle roll 8A, 8B, 8C ... 2nd bridle roll 9 ... Deflector roll 10 ... Dancer roll 11 ... Rope 12 ... Weight 13 ... Drum 14 ... Motor 15 ... Support shaft 16 ... Arm 17 ... Counterweight 18 ... Torque motor 19 ... Angle detector 20 ... Counterweight driving motor 21 ... Counterweight position detector 22 ... Heating zone 23 ... Soaking zone 24 ... Primary cooling zone 25 ... Overaging zone 26 ... Secondary cooling zone 27 ... Gas jet cooler 28 ... Water cooling tank 29 ... Dryer 30 ... Final cooling zone 31 ... Entry side Dancer rolls 32, 33 ... Tension detection roll 34 ... Outgoing dancer rolls 35, 36 ... Tension detector 37 ... Impact roll 38A, 38B, 39A, 39B ... Drive motor 40 ... Support roll 41, 42 ... Tension detector 43A, 43B, 44, 45A, 45B ... Inverter 46, 47, 48 ... Current controller 49, 50 ... Speed controller 51, 52 ... Tension controller 53 ... Position controller 54 ... Position setting value 55, 56 ... Tension setting value 57 ... Furnace speed reference value F ... Continuous annealing furnace S ... Steel strip W ... Deflection amount L ... Pass line Q ₁ , Q ₂ ... Inclination angle α ... Angles between the arm and the pass line T ₁ , T ₂ , T _M ... Steel strip tension

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshimitsu Honda 1-1 Tobata-cho, Tobata-ku, Kitakyushu, Fukuoka Prefecture Nippon Steel Corporation Yawata Works (72) Inventor Yasuo Kitawaki Tobata, Tobata-ku, Kitakyushu, Fukuoka Machi 1-1 Nippon Steel Co., Ltd. Yawata Works (72) Inventor Masao Ono 5-3 Tokai-cho, Tokai-shi, Aichi Prefecture Nippon Steel Co., Ltd. Nagoya Works (72) Inventor Yoshitaka Hattori Futtsu, Chiba Prefecture 20-1 Shintomi-shi, Nippon Steel Co., Ltd. (72) Inventor Hiroo Goshi 5-3 Tokai-cho, Tokai-shi, Aichi Prefecture Nippon Steel Co., Ltd. Nagoya Steel Works (72) Inventor Harumi Kato 46-59, Nakahara, Tobata-ku, Kitakyushu, Fukuoka Prefecture (56) References by Nippon Steel Plant Design Co., Ltd. (56) References JP-A-6-41648 (JP, A) JP-A-56-65938 (JP, A) (58) Survey Areas (Int.Cl. ⁷ , DB name) C21D 9/56 101 C21D 11/00 105

Claims (6)

(57) [Claims] 1. A heating zone, soaking zone, a primary cooling zone, overaging zone, in a continuous annealing furnace of a steel strip having a secondary cooling zone, the
Outside bridle on the inlet side and / or the outlet side of the continuous annealing furnace
In addition to the rolls, an in-furnace bridle roll is provided between the overaging zone and the secondary cooling zone, and the steel is used in the heating zone on the inlet side of the in-furnace bridle roll, the soaking zone, the primary cooling zone and the overaging zone.
The secondary cooling zone on the outlet side of the in-furnace bridle roll is reduced by lowering the tension of the steel strip to a range that avoids buckling and width shrinkage of the strip.
A continuous annealing device for steel strips, which increases the tension of the steel strips in a range that avoids meandering and loosening of the steel strips. 2. A steel that has been installed in the immediate entry side and / or immediately out side of your Keru processing equipment in a continuous process line of the steel strip
In the belt tension control device , the first bridle roll,
Between the second bridle roll and the two bridle rolls
The inclination angle θ of the traveling direction of the steel strip is in the range of 0 ° <θ <90 °.
A buffer roll that is in contact with the steel strip is provided in the surroundings , and the buffer roll is capable of swivel movement in a direction intersecting a path line that connects the rolls before and after the buffer roll according to the tension variation of the steel strip, and A tension control device for a steel strip, characterized by controlling an angle α formed between an arm of a buffer roll and a pass line to adjust the tension of the steel strip. 3. The angle α between the arm of the buffer roll and the pass line is defined as 0 ° <α ≦ α ₀ or α ₀ with a boundary of α ₀ where F has a maximum value as expressed by the following formula (1). ≤ α <90
3. The tension control device for a steel strip according to claim 2, wherein the tension of the steel strip is adjusted with an angle of 0 being a control range. [Equation 1] A: Buffer roll fulcrum b: Distance between pass line and fulcrum c: Distance between fulcrum and second bridle roll entry side roll α: Angle between buffer roll arm and pass line R: Buffer roll arm length a: No. Distance between the first bridle roll exit side roll (or deflector roll) and the second bridle roll entrance side roll (or deflector roll) T _M : plate tension F: force with which the buffer roll is pressed by the plate tension T _M 4. A buffer roll axis, is rotatably supported on the fixed to the support shaft arm, tension controller of the steel strip according to claim 2 or 3, wherein providing a torque motor for rotating the support shaft . 5. The tension control device for a steel strip according to claim 4, wherein a counterweight is provided on the support shaft. 6. The out-of-furnace bridle roll comprises:
It is a tension control device for a steel strip according to any one of 1 to 5.
The continuous annealing apparatus for a steel strip according to claim 1, wherein