JP2005232495A - Facility and method for heat-treating metal strip - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat treatment facility and a heat treatment method with which a metal strip having desired characteristic can be produced without lowering the productivity and the quality. <P>SOLUTION: A shape-flattening device 7 composed of pinch rolls etc., is disposed to the inlet side and the outlet side of the induction-heating device 6. In this way, the stable passing-through of the strip can be performed into the induction-heating device 6 for metal strip. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a heat treatment facility and a heat treatment method for a metal strip for performing reheating treatment for material adjustment after, for example, continuous annealing and rapid cooling.

  In the continuous annealing of the metal strip, it is important to control the heat treatment conditions of heating and cooling in order to impart desired mechanical properties to the metal strip to be treated. In particular, in recent years, the demand for high-tensile materials has increased, and the importance of rapid cooling technology advantageous for the production of high-tensile materials has increased. Examples of the rapid cooling method include a water quenching method, a roll cooling method, an air / water mixing (mist) cooling method, and a gas jet cooling method, which are appropriately selected in order to obtain a necessary material.

  Further, in the reheating zone performed after the rapid cooling, an appropriate mechanical crown is provided to the in-furnace roll so that the continuous feeding of the metal strip that is continuously conveyed is performed. However, a thermal crown is generated in the in-furnace roll due to the influence of the metal strip plate temperature and the ambient temperature around the in-furnace roll. If the difference between the mechanical crown amount of the in-furnace roll in the initial state and the thermal crown amount of the in-furnace roll generated during operation is within an appropriate range, and if automatic alignment is to be provided, the plate will be stable. Done. However, when the difference in the crown amount is remarkably large, a compressive force is applied in the width direction of the metal band, which causes the metal band to buckle in the width direction and cause a throttling, or the passage plate becomes unstable and meandering occurs. There is a risk that the operation may become impossible.

As a means for solving this problem, there is a technique described in Patent Document 1. In the technique disclosed in this document, an induction heating device is arranged as a rapid heating device between the cooling zone and the reheating zone, and the temperature of the metal zone by the induction heating device is controlled to obtain an appropriate thermal crown amount. It adjusts and aims at a stable threading plate.
Japanese Patent Publication No. 7-13271 (Patent No. 1984298)

The technique described in Patent Document 1 uses the induction heating device having excellent temperature controllability and responsiveness, and is therefore the best method for adjusting the thermal crown amount.
However, if the shape of the metal band is disturbed when entering the induction heating device, the compressive stress due to the increase in the temperature gradient dT / dx in the metal band longitudinal direction due to rapid heating acts in the metal band width direction. As a result, the shape of the metal band is further disturbed, and in some cases, the metal band comes into contact with the induction heating coil, causing damage to the induction heating device or damage to the metal band. Alternatively, meandering may occur in the furnace due to a defective shape of the metal band, and the metal band passing plate may become unstable, and accordingly, the line speed cannot be increased and the efficiency may be reduced.
For this reason, when performing rapid heating by the induction heating device, it is preferable to pass the plate while keeping the plate shape as flat as possible when passing through the induction heating device.
The present invention has been made paying attention to such points, and provides a heat treatment facility and a heat treatment method capable of producing a metal strip having desired characteristics without lowering productivity and quality. Let it be an issue.

In order to solve the above problems, the present invention keeps the metal band pass line constant when the metal band after quenching or rapid cooling passes through the induction heating device, and the shape of the metal band in the width direction. It has been invented that it has been found that the flat plate can secure a stable plate in the furnace.
That is, the invention described in claim 1 is a heat treatment facility for a metal strip that is continuously reheated by an induction heating device after sequentially cooling the metal strip that is being conveyed,
A shape flattening device for flattening the shape of the metal strip conveyed is disposed on at least one of the inlet side and the outlet side of the induction heating device.

  Next, in the invention described in claim 2, in contrast to the configuration described in claim 1, the induction heating device is configured by a row of a plurality of induction heating devices arranged along a pass line, and the plurality of induction heating devices. At least one location between the plurality of induction heating furnaces arranged on at least one of the entry side and the exit side of the row of devices or without being placed on the entry side and the exit side of the row of the plurality of induction heating devices Further, the above-described shape flattening device is arranged.

Next, the invention described in claim 3 is the configuration described in claim 1 or claim 2, wherein the shape flattening device is configured to restrain the metal band by a roll disposed with the metal band interposed therebetween, and The metal band is flattened by at least one of the restraints of the metal band by the gas jetted from the gas jet nozzle arranged with the metal band interposed therebetween.
Next, in the invention described in claim 4, the shape of the induction heating device arranged adjacent to the shape flattening device from the restraint position by the shape flattening device is compared with the configuration described in claim 3. The distance from the flattening device to the exit or entry side at the distal position is set to 1.5 times or less the plate width of the metal band, or the distance between the restraining positions by the shape flattening device is set to the metal band plate It is characterized by being set to 3 times or less of the width.

Next, the invention described in claim 5 is flat with respect to the configuration described in any one of claims 1 to 3, wherein the shape is flat on the entry side of the induction heating device, including a pair of deflection rolls. It is characterized by having arranged the conversion apparatus.
Next, the invention described in claim 6 is a heat treatment method for a metal strip, in which the metal strips that are continuously conveyed are sequentially cooled and then reheated by an induction heating device.
In the shape flattening device for flattening the shape of the metal band, the flattening of the metal band portion passing through the induction heating device is improved.

Next, in the invention described in claim 7, in contrast to the configuration described in claim 6, the induction heating device includes a row of a plurality of induction heating devices arranged along a pass line, and the plurality of induction heating devices. The metal band portion that passes through the induction heating device of at least one furnace of the device is flattened by the shape flattening device.
Next, according to an eighth aspect of the present invention, in the configuration described in the sixth or seventh aspect, the shape flattening device includes a metal band constrained by a roll arranged with the metal band interposed therebetween, and The metal band is flattened by at least one of the restraints of the metal band by the gas jetted from the gas jet nozzle arranged with the metal band interposed therebetween.

  Next, the invention described in claim 9 is based on the configuration described in claim 8 from the restraint position in the induction heating device disposed adjacent to the restraint position from the restraint position by the shape flattening device. The distance to the exit side or entry side at the distal position is set to 1.5 times or less of the plate width of the metal band, or the distance between adjacent restraint positions is set to 3 times or less of the plate width of the metal band. It is characterized by that.

Next, the invention described in claim 10 is directed to the structure described in any one of claims 6 to 8 by using a pair of deflection rolls arranged on the entrance side of the induction heating device. It is characterized by flattening.
Here, the shape flattening device, for example, flattens the metal band by restraining the metal band from both sides in the plate thickness direction, and suppresses vibration of the metal band being conveyed by restraining the metal band. .
The metal band is restrained by this shape flattening device by, for example, a pair of pinch rolls, or at least three gasses arranged at positions that are alternately opposed to the metal band at positions shifted in the longitudinal direction of the metal band. It is restrained by the jet gas from the jet nozzle. Further, the shape flattening device may be configured by a shape correction device such as a deflection roll.

The reasons for the limitation to 1.5 times or less or 3 times or less the plate width will be described.
The metal band once flattened by the shape flattening device is gradually restored to the original shape as it leaves the restraining position by the shape flattening device. As a result of various studies by the inventors, the distance at which the metal band is restored to the original shape from the restraint position is proportional to the plate width of the metal band, and within 1.5 times the plate width of the metal band from the restraint position. It was found that the shape of the metal band does not collapse greatly and can be stably passed if the distance is.

From this, the distance from the restraint position by the shape flattening device to the exit side or the entry side at the distal position from the shape flattening device in the induction heating device arranged adjacent to the shape flattening device is determined. It is limited to not more than 1.5 times the plate width of the metal strip.
In addition, as described above, the effect of flattening by each shape flattening device is up to 1.5 times the plate width of the metal strip toward the upstream side and the downstream side centering on the restraint position. If the distance between the two restraining positions by the flattening device is set to be not more than three times the plate width of the metal strip, stable plate passing becomes possible. From this point, it is limited to 3 times or less.

According to the present invention, the flattening of the metal band passing through the induction heating device is improved, and as a result, a stable pass line can be secured. As a result, the line speed can be increased, which can contribute to efficiency improvement.
In addition, because the risk of damage to the induction heating device due to the metal band and the damage to the metal band can be avoided, the distance between the metal band and the induction heating coil can be reduced, resulting in improved heating efficiency of the induction heating device. This also has the effect of reducing the power consumption rate.

Next, a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram showing an example in which the present invention is applied to a continuous annealing equipment for a metal strip.
In the continuous annealing facility according to the present embodiment, as shown in FIG. 1, a heating zone 2, a soaking zone 3, a gas jet cooling zone 4, a rapid cooling for continuously heating the metal zone 1 that is continuously conveyed from the upstream side. A band 5, an induction heating device 6, a reheating zone 8, and a final cooling zone 9 are arranged. And the shape planarization apparatus 7 is arrange | positioned at the entrance side and exit side of the said induction heating apparatus 6, respectively, and is comprised. Reference numerals 23 and 24 denote front and rear loopers, reference numeral 20 denotes a payoff reel, and reference numeral 21 denotes a coiler.

Each shape flattening device 7 of the present embodiment includes a pinch roll 10 as shown in FIG. The pinch roll 10 sandwiches the metal band 1 from both the front and back sides and restrains the metal band 1, thereby flattening the shape of the metal band 1 and reducing the vibration of the metal band 1 by the restraint.
The distance between the pinch rolls 10 arranged across the induction heating device 6 (the distance between the two restraint positions) is set to be a distance within three times the minimum plate width of the target metal strip 1, The induction heating device 6 disposed between the two sets of pinch rolls 10 also uses a plate passage that fits within less than three times the minimum plate width of the metal strip 1 as the object.

Next, the operation and effect of the equipment with the above configuration will be described.
The continuously unwound metal strip 1 is continuously transported and annealed in the heating zone 2, the soaking zone 3, and the gas jet cooling zone 4, and after the rapid cooling in the rapid cooling zone 5, The material is adjusted by performing reheating in the induction heating device 6 and the reheating zone 8, and further cooled in the final cooling zone 9 and wound around the coiler 21.

  Here, as the rapid cooling zone 5, for example, when the water quenching method capable of performing the fastest cooling is used, the metal strip 1 is likely to warp due to the rapid cooling. Since the warp of the metal band 1 generated in the rapid cooling zone 5 remains even after passing through the rapid cooling zone 5, if the shape flattening device 7 is not provided, it enters the induction heating device 6 with a bad shape. . And the shape of the metal strip 1 is further deteriorated by the thermal stress at the time of rapid heating in the induction heating device 6. For example, when the metal strip 1 having a thickness of 1.0 mm has a poor plate shape when entering the induction heating device 6 and the amount of warpage is about 30 mm, induction heating is performed at a heating rate of 60 ° C./s. Warpage increases as the opening width 110 mm of the device 6 is contacted. As a means for preventing the metal strip 1 from coming into contact with the induction heating device 6, it is conceivable to increase the width of the entrance of the induction heating device 6, but if the opening width is increased, the heating efficiency decreases.

On the other hand, in the present embodiment, the shape flattening device 7 is disposed on the entry side and the exit side of the induction heating device 6 to flatten the shape such as the warp of the metal band 1 in the portion that passes through the induction heating device 6. As a result, the distance between the metal strip 1 and the induction heating coil when passing through the induction heating device 6 can be kept constant, and stable plate passing is possible.
Here, the metal strip 1 once flattened on the entry side of the induction heating device 6 gradually recovers to its original shape as it leaves the restraining position. If the distance from which the metal band 1 is restored to its original shape from the restraining position is distances L1 and L2 within 1.5 times the plate width of the metal band 1, the shape of the metal band 1 is not greatly collapsed. Can pass through, stable. In this embodiment, since the metal band 1 shape is flattened from both the entrance side and the exit side of the induction heating device 6, the distance L3 between the two shape flattening devices 7 is set to the plate of the metal band 1. By suppressing the width to 3 times or less of the width, the distance from the induction heating coil can be kept constant in the portion of the metal band 1 that passes through the induction heating device 6, and stable plate passing is possible.

  In the present embodiment, by providing the shape flattening device 7 on both the entrance side and the exit side of the induction heating device 6, a restraint position is provided on both sides of the induction heating device 6, as described above. Longer distances can be kept flat. However, if the length of the metal band 1 in the induction heating device 6 in the traveling direction of the metal band is sufficiently shorter than the distance at which the shape of the metal band 1 is restored, that is, the plate passing distance of the metal band 1 in the induction heating device 6 If the sum L1, L2 of the distance between the heating device 6 and one shape flattening device 7 is not more than 1.5 times the plate width of the minimum dimension of the target metal strip 1, for example, the induction heating device 6 The shape flattening device 7 may be disposed only on the entrance side of the. The shape of the metal band 1 gradually recovers to the initial shape as the distance from the contact position between the pinch roll 10 and the metal band 1 is increased. However, if the induction heating device 6 is short, sufficient flattening is achieved as described above. can get. In addition, although the effect is acquired even if it installs the pinch roll 10 in the exit side of the induction heating apparatus 6, the entrance side is desirable. Furthermore, if the pinch rolls 10 are installed on both the front and rear sides of the induction heating device 6 as described above, a larger shape suppression effect can be obtained.

  The same can be said for the vibration reduction effect of the metal strip 1 by the shape flattening device 7. That is, the amplitude of the vibration of the metal band 1 becomes smaller as the support point interval of the metal band 1 is shorter. Therefore, when the pinch roll 10 exists between the upstream and downstream conveying rolls of the induction heating device 6, the amplitude of the metal strip 1 becomes small. Even if the position of the pinch roll 10 is arranged on one of the entrance side and the exit side of the induction heating device 6, the same effect can be obtained. As the distance from the restraint position of the metal band 1 by the pinch roll 10 increases, the vibration amplitude of the metal band 1 increases. However, if the pinch roll 10 is installed both before and after the induction heating device 6, the distance between the support points is increased accordingly. Becomes shorter and a higher damping effect can be obtained.

Two or more induction heating devices 6 may be disposed between the two pinch rolls 10. In short, there is no problem if the distance between the two pinch rolls 10 can be set to 3 times or less the plate width of the metal strip 1.
Further, as a result of limiting the size of the induction heating device 6 as described above, when the target reheating is not ensured in the induction heating device 6 of one furnace, a plurality of induction heating devices are used as shown in FIG. 6 constitutes a row of induction heating devices, and a shape flattening device 7 may be arranged on the entry side of each induction heating device 6. In the example shown in FIG. 3, in the upstream induction heating device 6, the shape flattening device 7 is arranged on both the inlet side and the outlet side, which is longer than the plate passing distance in the downstream induction heating device 6. The plate distance of the metal strip 1 can be increased.

  Further, the distance from the inlet side of the induction heating device 6 on the upstream side to the shape flattening device 7 arranged between the induction heating devices 6 in FIG. 3 and the exit of the induction heating device 6 on the downstream side from the shape flattening device 7. When both the distances to the side are within 1.5 times the plate width of the metal strip 1, the shape flattening device 7 disposed on the inlet side of the upstream induction heating device 6 may be omitted. I do not care. Moreover, the row | line | column of the induction heating apparatus 6 is not necessarily limited to 2 furnaces, You may be comprised from 3 or more furnaces. Even in that case, the shape flattening device 7 may be disposed between the induction heating devices 6 as appropriate.

Even when the length of each induction heating device 6 is sufficiently short, by providing the induction heating device 6 on the entry / exit side, the pass line can be further stabilized, the induction heating coil can be brought closer to the metal strip 1, and the heating efficiency can be improved. It is more preferable because it becomes possible to improve.
The shape flattening device 7 is not limited to the contact type using the pinch roll 10 or the like as long as the metal band 1 can be flattened. For example, a non-contact type using fluid pressure or magnetic force as in the second embodiment may be used. In short, any device that can flatten the metal strip 1 may be used. In some cases, the shape flattening device 7 may be disposed in the induction heating device 6.
The metal strip 1 to which the present invention can be applied is not particularly limited, such as a steel plate or aluminum.

Next, a second embodiment will be described with reference to the drawings. In addition, about the apparatus similar to the said embodiment, the same code | symbol is attached | subjected and demonstrated.
This embodiment is the same as the first embodiment except that the shape flattening device 7 to be used is different.
As shown in FIG. 4, the shape flattening device 7 of the present embodiment is composed of three gas injection nozzles 11 a and 11 b arranged in a staggered manner with the metal band 1 interposed therebetween.
Each gas injection nozzle 11 is provided with a slit-like opening that is long in the width direction of the metal strip 1, and a gas is injected from the opening to the entire width direction of the metal strip 1 to apply a predetermined injection pressure. In the gas injection nozzle, the nozzle 11 a facing the front surface side of the metal band 1 and the nozzle 11 b facing the back surface side of the metal band 1 alternately face each other at a position shifted in the longitudinal direction of the metal band 1. Are arranged in a staggered manner.

Thus, by jetting a jet stream from the position shifted on the front and back of the metal band 1 to the metal band 1, it is possible to impart a minute warp (L warp) in the longitudinal direction (L direction) of the metal band 1, The width direction component (C warpage component) of the residual stress in the metal band 1 is converted into an L warpage component, and thus the C warpage is corrected. Further, it is considered that the metal band 1 is bent in the L direction, so that rigidity is imparted to the metal band 1 and vibration is also suppressed. It should be noted that the displacement of the nozzle 11a and the nozzle 11b in the metal band longitudinal direction at the position where the nozzle 11a faces the metal band 1 is preferably a position shifted by about 1/2 pitch on the front and back of the metal band 1. Further, the number of nozzles 11a and 11b is at least three, and the effect increases as the number increases, but may be selected as appropriate. Similarly to the pinch roll 10, the shape flattening device using the gas injection nozzle may be installed on either the entry side or the exit side of the induction heating device 6, but the entry side is preferable, and both sides are preferable. If installed, the shape correction and damping effect will be enhanced.
Other configurations, operations, and effects are the same as those in the first embodiment.
Here, in each embodiment, although the same kind is used as the shape flattening device 7 used in one line, it may be used in appropriate combination.

Next, a third embodiment will be described with reference to the drawings. In addition, about the apparatus similar to the said embodiment, the same code | symbol is attached | subjected and demonstrated.
As shown in FIG. 5, the present embodiment is the same as the first embodiment except that the shape flattening device 7 to be used is different.
The shape flattening device 7 of this embodiment is composed of a pair of deflection rolls 12 that are shape correction devices. The pair of deflection rolls 12 are arranged with the metal band 1 in between, and by optimizing the pushing amount of the deflection roll 12, the shape correction of the metal band 1 can be more effectively performed. 1 can be flattened.

  Compared with the case where the pair of pinch rolls 10 is used, it is preferable to use a shape correction device such as the deflection roll 12 as the shape flattening device 7 because flattening can be realized more reliably. In addition, when flattening the shape with a shape correction device such as the deflection roll 12, the metal band 1 does not restore to the original shape, so the size of the induction heating device 6 is set to be large accordingly. it can.

In addition, when the shape straightening device including the deflection roll 12 is arranged as the shape flattening device 7 on the inlet side of the induction heating device 6, the shape flattening device 7 is not necessarily required on the outlet side. Even when the shape flattening device 7 is arranged on the side, the pair of pinch rolls 10 and the shape flattening device 7 by gas injection may be arranged.
Other configurations, operations and effects are the same as those in the above embodiment.
Note that, in either the pinch roll 10 or the deflection roll 12, a rolling force that sufficiently suppresses the deformation of the metal band 1 and a rotation that follows the conveyance of the metal band 1 so as not to scratch the metal band 1. It is preferable to use a drive roll with force.

Examples of the present invention will be described below in comparison with examples of the conventional method.
(Example 1)
Using the continuous annealing line shown in FIG. 1, a cold-rolled steel sheet having a sheet thickness of 0.8 mm and a sheet width of 1800 mm was manufactured. A water quenching apparatus was used for the rapid cooling zone, and the steel sheet was heated from 200 ° C. to 400 ° C. by the induction heating device 6 at a heating rate of 90 ° C./s.
The shape flattening device 7 of the steel strip was installed only on the entry side of the induction heating device 6 using the pinch roll 10 shown in FIG. The said pinch roll 10 was installed in the position where the distance from the steel strip restraint position by the pinch roll 10 to the exit side of the induction heating apparatus 6 will be 1600 mm. The roll diameter of the pinch roll 10 is 350 mm, which is the same diameter on both the front and back surfaces.

As a conventional method, even when there was no shape flattening device 7 such as the pinch roll 10 before and after the induction heating device 6, the comparison was performed under the same conditions.
The index for flattening the shape of the steel strip was the amount of meandering by the end detector of the steel strip installed in the reheating zone. This is because if the induction heating device 6 can perform uniform heating in the width direction of the steel strip, the crown amount of the roll in the reheating zone 8 maintains an appropriate value and can be regarded as a stable plate with less meandering. .

  In the case of the method of the present invention, by using the pinch roll 10, the distance between the induction heating coil and the steel strip can be kept constant, and the temperature unevenness in the width direction of the steel strip has been reduced. The amount of meandering of the threading plate was 17 mm. On the other hand, in the conventional method, due to the disturbance in the shape of the steel strip generated by the water quenching device, the induction heating device 6 causes non-uniform heating in the width direction of the steel strip, the amount of thermal crown in the reheating zone is not stable, and meandering The amount was 100 mm or more, and it was impossible to continuously operate unless the line speed was reduced.

(Example 2)
As in Example 1, using the continuous annealing line shown in FIG. 1, when manufacturing a cold-rolled steel sheet having a plate thickness of 0.8 mm and a plate width of 1800 mm, it was shown in FIG. The gas injection nozzle was used and installed only on the entry side of the induction heating device 6.
The slit width of the gas injection nozzles 11a and 11b is 2000 mm, and the gap in the transport direction of each gas injection nozzle is 2 mm. The gas injection nozzles 11a and 11b are configured by arranging a total of three, one on the front and two on the back. Further, the distance between the nozzle and the steel strip was adjusted in advance to be 30 mm, and the injection pressure from each nozzle was set to 15 kPa.
Other implementation conditions are the same as in the first embodiment. And when based on this invention, the amount of meandering of the threading board in a reheating zone was 23 mm.

(Example 3)
The deflection shown in FIG. 5 as a steel strip shape straightening device when manufacturing a cold rolled steel sheet having a thickness of 0.8 mm and a width of 1800 mm using the continuous annealing line shown in FIG. 1 as in Example 1. The roll 12 was used and installed only on the entry side of the induction heating device 6. Other implementation conditions are the same as in the first embodiment.
By appropriately adjusting the pushing amount of the deflection roll 12, the meandering amount of the passing plate in the reheating zone 8 was 11 mm. That is, it can be seen that the meandering amount can be suppressed most in the three embodiments.

It is a schematic block diagram which shows an example of the continuous annealing equipment of the metal strip which concerns on 1st Embodiment based on this invention. It is the schematic which shows an example of the shape planarization apparatus which concerns on 1st Embodiment based on this invention. It is a schematic block diagram which shows another example of the continuous annealing equipment of the metal strip which concerns on embodiment based on this invention. It is the schematic which shows an example of the shape planarization apparatus which concerns on 2nd Embodiment based on this invention. It is the schematic which shows an example of the shape planarization apparatus which concerns on 3rd Embodiment based on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Metal zone 2 Heating zone 3 Soaking zone 4 Gas jet cooling zone 5 Rapid cooling zone 6 Induction heating device 7 Shape flattening device 8 Reheating zone 9 Final cooling zone 10 Pinch roll 11a, 11b, 11c Gas injection nozzle 12 Deflection roll (Shape correction device)
L1 Distance from the restraint position to the induction heating device exit side L2 Distance from the restraint position to the induction heating device entry side L3 Distance between adjacent restraint positions

Claims (10)

In the heat treatment equipment for the metal strip that is continuously reheated by the induction heating device after cooling the metal strip that is continuously conveyed,
A heat treatment facility for a metal band, wherein a shape flattening device for flattening the shape of the metal band being conveyed is disposed on at least one of an inlet side and an outlet side of the induction heating device.   The induction heating device includes a plurality of rows of induction heating devices arranged along a pass line, and is arranged on at least one of an entry side and an exit side of the row of the plurality of induction heating devices, or the plurality of induction heating devices. 2. The shape flattening device according to claim 1, wherein the shape flattening device is disposed at least at one position between the plurality of induction heating furnaces without being arranged on an entry side and an exit side of a row of heating devices. Heat treatment equipment for metal strips.   The shape flattening device has at least one of restraint of the metal band by a roll arranged with the metal band interposed therebetween and restraint of the metal band by a gas jetted from a gas injection nozzle arranged with the metal band sandwiched therebetween. The heat treatment equipment for a metal band according to claim 1 or 2, wherein the metal band is flattened by restraint.   The distance from the constrained position by the shape flattening device to the exit side or the entry side at the distal position from the shape flattening device in the induction heating device arranged adjacent to the shape flattening device is defined as a metal band. The metal strip according to claim 3, wherein the plate width is set to 1.5 times or less, or the distance between the restraining positions by the shape flattening device is set to 3 times or less the plate width of the metal strip. Heat treatment equipment.   The metal band heat treatment facility according to any one of claims 1 to 3, wherein the shape flattening device including a pair of deflection rolls is disposed on an inlet side of the induction heating device. In the metal band heat treatment method in which the metal band continuously conveyed is sequentially cooled and then reheated by an induction heating device.
A shape flattening device for flattening a shape of a metal band, wherein the flattening of the metal band portion passing through the induction heating device is improved.   The induction heating device includes a plurality of rows of induction heating devices arranged along a pass line, and a metal band portion that passes through the induction heating device of at least one furnace of the plurality of induction heating devices is formed by the shape flattening device. The metal band heat treatment method according to claim 6, wherein the metal band is flattened.   The shape flattening device has at least one of restraint of the metal band by a roll arranged with the metal band interposed therebetween and restraint of the metal band by a gas jetted from a gas injection nozzle arranged with the metal band sandwiched therebetween. The metal band heat treatment method according to claim 6 or 7, wherein the metal band is flattened by restraint.   The distance from the restraint position by the shape flattening device to the exit side or the entry side at the distal position from the restraint position in the induction heating device arranged adjacent to the restraint position is the plate width of the metal strip. The metal band heat treatment method according to claim 8, wherein the metal band heat treatment method is set to 1.5 times or less, or a distance between adjacent constraining positions is set to 3 times or less of a plate width of the metal band.   The metal band heat treatment method according to any one of claims 6 to 8, wherein the metal band is flattened by a pair of deflection rolls arranged on the entry side of the induction heating device.

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