JPH09137233A - Method for heat treating band-shaped metallic sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reform the detect in the shape without needing a separate shape reforming device at the time of subjecting a band-shaped metallic sheet to continuous heat treatment in the combination of a heating furnace, a soaking furnace or the like and an electric heater and furthermore to prevent the generation of the detect in the shape following electric heater. SOLUTION: This continuous heat treating method is the one in which the tension of a band-shaped steel sheet 20 is held to certain one by a tension applying means provided on the inlet side and outlet side of a continuous heat treating furnace, which is continuously fed to a heating zone, and furthermore, the sheet is continuously passed through an electric heater 30 provided before and/or behind the heating zone. The tension UT (kg/mm<2> ) of the steel sheet 20 between conductive rolls 31 and 33 on the low temp. side and high temp. side is regulated to the limit of the slip between the conductive rolls 31 and 33 or below and is also regulated to the one satisfying 0.5σy (T)<=UT<=2.5σy(T), i.e., the relational inequality with the yield stress σy (kg/mm<2> ) of the steel sheet 20 at the heating temp. T ( deg.C) to draw the steel sheet 20, and furthermore, its tension (UT)' in the place other than the electric heater 30 is regulated to <=50σy.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【発明の属する技術分野】本発明は、例えば帯状鋼板等
に焼入や焼鈍等を施すための連続熱処理方法に係り、特
に加熱炉や均熱炉等と通電加熱装置とを組み合わせた際
の帯状金属板の連続熱処理方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous heat treatment method for, for example, quenching or annealing a strip-shaped steel sheet or the like, and particularly when a heating furnace or a soaking furnace is combined with an electric heating device. The present invention relates to a continuous heat treatment method for a metal plate.

【０００２】[0002]

【従来の技術】従来の連続熱処理炉、例えば連続焼鈍炉
の一例を図５に示す。１はアンコイラー、２は溶接機、
３は前面ルーパー、４は予熱炉、５は加熱炉で、加熱装
置としてラジアントチューブや直火バーナー、電気ヒー
ター等が一般的に設けられている。６は均熱炉、７は冷
却帯である。９はメッキポット、１０はワイピングノズ
ルであり、１１は気体冷却装置、１２は水冷装置、１３
は後面ルーパー、１４は調質圧延機、１５は後処理装
置、１６はドライヤー、１７はコイラーである。2. Description of the Related Art FIG. 5 shows an example of a conventional continuous heat treatment furnace, for example, a continuous annealing furnace. 1 is an uncoiler, 2 is a welder,
Reference numeral 3 is a front looper, 4 is a preheating furnace, 5 is a heating furnace, and a radiant tube, an open flame burner, an electric heater or the like is generally provided as a heating device. 6 is a soaking furnace, and 7 is a cooling zone. 9 is a plating pot, 10 is a wiping nozzle, 11 is a gas cooling device, 12 is a water cooling device, 13
Is a rear surface looper, 14 is a temper rolling mill, 15 is a post-treatment device, 16 is a dryer, and 17 is a coiler.

【０００３】上記のような構成においては、連続焼鈍炉
の入側及び出側に設けられたブライドル１８やダンサー
ロール１９等の張力付与装置により、炉部内を連続送給
される帯状鋼板２０の張力が設定されている。この場合
の炉部における鋼板２０の張力の値は、板破断、ヒート
バックル等を防止するため、単位断面積当たり約１ｋｇ
／ｍｍ² 以下の低い値に設定するのが一般的である。In the above-mentioned structure, the tension of the strip-shaped steel plate 20 continuously fed in the furnace portion is controlled by the tension applying devices such as the bridle 18 and the dancer roll 19 provided on the inlet side and the outlet side of the continuous annealing furnace. Is set. The value of the tension of the steel plate 20 in the furnace part in this case is about 1 kg per unit cross-sectional area in order to prevent plate breakage, heat buckle, etc.
Generally, it is set to a low value of / mm ² or less.

【０００４】一方、冷延鋼板等の帯状鋼板を連続熱処理
するための加熱方法としては、特公昭６０−２６８１８
号公報に記載されているように、鋼板に通電ロールを介
して直接通電し、鋼板自体のジュール熱により加熱する
方法がある。また、特開平１−１４２０３２号公報、特
開平１−１８７７８９号公報に記載されているように、
環状トランスを貫通する鋼板通路の前後に通電ロールを
設け、両通電ロールを導電性部材で接続して鋼板、通電
ロール及び導電性部材により閉回路を構成し、環状トラ
ンスに外部電源から交流電流を通電することにより上記
閉回路を二次コイルとして誘導電流を発生させ、この誘
導電流によるジュール熱で鋼板を加熱する方法がある。On the other hand, as a heating method for continuously heat treating a strip-shaped steel sheet such as a cold-rolled steel sheet, Japanese Patent Publication No. 60-26818.
As described in the publication, there is a method of directly energizing a steel sheet through an energizing roll and heating it by Joule heat of the steel sheet itself. Further, as described in JP-A Nos. 1-142032 and 1-187789,
An energizing roll is provided before and after the steel plate passage that penetrates the annular transformer, and both energizing rolls are connected by a conductive member to form a closed circuit with the steel plate, the energizing roll and the conductive member, and an alternating current is supplied to the annular transformer from an external power source. There is a method in which an electric current is generated by using the closed circuit as a secondary coil by applying an electric current, and the steel sheet is heated by Joule heat generated by the electric current.

【０００５】これら鋼板に直接電流を通し、ジュール熱
で加熱する方法は、直火型無酸化加熱、輻射管加熱、間
接電気加熱等の伝熱による加熱に比べて単位時間当たり
の加熱能力が高く、設備をコンパクトにすることがで
き、また熱応答性が非常に良いことから加熱制御が容易
である等の点で優れている。The method of directly applying an electric current to these steel sheets and heating them by Joule heat has a higher heating capacity per unit time than heating by heat transfer such as direct fire type non-oxidizing heating, radiant tube heating and indirect electric heating. Further, the equipment can be made compact, and the heat response is very good, so that it is excellent in that heating control is easy.

【０００６】そこで、このような通電加熱装置を上述し
たような連続熱処理炉の途中に組み込んだものが、特開
平７−１０９５２９号公報に開示されている。即ち、図
６に示すような構成であり、（ａ）は加熱炉５の前に通
電加熱装置３０を設けた例、（ｂ）は加熱炉５の間に通
電加熱装置３０を設けた例、（ｃ）は加熱炉５の前後に
通電加熱装置３０を設けた例、（ｄ）は加熱炉５の後に
通電加熱装置３０を設けた例である。なお、（ｃ）では
通電加熱装置３０の後にさらに均熱炉６を設け、（ｄ）
では通電加熱装置３０の後に徐冷帯７を設けている。Therefore, Japanese Patent Application Laid-Open No. 7-109529 discloses a device in which such an electric heating device is incorporated in the middle of the above continuous heat treatment furnace. That is, the structure is as shown in FIG. 6, (a) is an example in which the electric heating device 30 is provided in front of the heating furnace 5, (b) is an example in which the electric heating device 30 is provided between the heating furnaces 5, (C) is an example in which the electric heating device 30 is provided before and after the heating furnace 5, and (d) is an example in which the electric heating device 30 is provided after the heating furnace 5. In addition, in (c), a soaking furnace 6 is further provided after the electric heating device 30, and (d)
Then, the slow cooling zone 7 is provided after the electric heating device 30.

【０００７】このような連続熱処理炉によれば、通電加
熱装置３０の加熱能力が極めて大きく、加熱量の迅速な
調整も容易である点を活かして、種々の条件の変動に対
して迅速に加熱量を増減して対応できるだけでなく、加
熱炉５や均熱炉６等と通電加熱装置３０との組み合わせ
により、種々の加熱パターンによる加熱が可能となる。According to such a continuous heat treatment furnace, taking advantage of the fact that the heating capacity of the electric heating device 30 is extremely large and the amount of heating can be adjusted quickly, the rapid heating can be performed with respect to changes in various conditions. Not only can the amount be increased / decreased, but also the combination of the heating furnace 5, the soaking furnace 6 and the electric heating device 30 enables heating with various heating patterns.

【０００８】[0008]

【発明が解決しようとする課題】しかしながら、上述し
たような連続熱処理炉において、従来のような一定の低
張力にて帯状鋼板を連続送給して操業を行うと、次のよ
うな問題が生じる。即ち、通電加熱装置において、通電
ロールは鋼板の加熱開始側の端と終了側の端とで鋼板に
接触し通電する必要があるが、スパーク発生を防止する
ために鋼板を通電ロールと押えロールとで挟持し、一定
の圧下をかけざるを得ない。そのため、通電ロール近傍
での鋼板の蛇行、加熱終了側の端での高温の鋼板と通電
ロールとの接触による急冷等に起因する形状不良が発生
するという問題がある。特に鋼板として板厚０．５ｍｍ
以下の薄鋼板を焼鈍温度６００〜９００℃で連続焼鈍す
る場合など形状不良の発生が著しい。However, in the continuous heat treatment furnace as described above, when the strip-shaped steel sheet is continuously fed at a constant low tension as in the prior art to carry out the operation, the following problems occur. . That is, in the electric heating device, the electric current roll needs to contact the steel plate at the end of the heating start side and the end of the heating side of the steel plate to energize, but to prevent the occurrence of sparks, the steel plate is divided into the electric current roll and the pressing roll. There is no choice but to sandwich it and apply a certain amount of reduction. Therefore, there is a problem that a shape defect occurs due to meandering of the steel sheet in the vicinity of the energizing roll and rapid cooling due to contact between the high temperature steel sheet at the end on the heating end side and the energizing roll. Especially as a steel plate 0.5 mm thick
When the following thin steel sheets are continuously annealed at an annealing temperature of 600 to 900 ° C, the occurrence of shape defects is remarkable.

【０００９】ところで、焼鈍のため熱処理する鋼板は、
それ以前の工程で耳波や中伸びといった形状不良を有す
ることがある。そして、形状不良の鋼板を通電ロールと
押えロールとで挟持して通板すると、鋼板が蛇行して形
状不良が一層激しくなったり、鋼板の破断につながる危
険がある。By the way, the steel sheet to be heat treated for annealing is
There may be a shape defect such as an ear wave or a middle stretch in the process before that. When a steel sheet having a poor shape is sandwiched between a current-carrying roll and a pressing roll and passed through, the steel sheet meanders, resulting in a more severe shape defect and a risk of breaking the steel sheet.

【００１０】この鋼板の蛇行を防止するため、例えば特
開昭６２−６７１２２号公報には、竪型連続焼鈍炉の入
側で鋼板を予め平坦に形状矯正した後焼鈍する方法が記
載されている。また、特願平４−３０４４５１号明細書
には、鋼板を０．１〜２％圧下した後、前述の通電加熱
を行う方法が記載されている。In order to prevent the meandering of the steel sheet, for example, Japanese Patent Application Laid-Open No. 62-67122 discloses a method in which the steel sheet is preliminarily flattened on the inlet side of a vertical continuous annealing furnace and then annealed. . In addition, Japanese Patent Application No. 4-304451 describes a method in which a steel plate is pressed down by 0.1 to 2% and then the above-mentioned electric heating is performed.

【００１１】しかし、前述の方法はいずれも形状矯正後
に焼鈍する方法であり、焼鈍装置とは別個に形状矯正装
置が必要となる。However, all of the above-mentioned methods are methods of annealing after shape correction, and a shape correction apparatus is required separately from the annealing apparatus.

【００１２】また、通電加熱に伴って鋼板進行方向に矩
形状の縦筋が発生する形状不良について、特願平５−１
０１８０８号明細書においては、通電ロールとの接触伝
熱による鋼板の温度降下量を規定することによって形状
不良を防止できるとされている。Further, regarding a shape defect in which a rectangular vertical streak is generated in the traveling direction of the steel sheet due to heating by energization, Japanese Patent Application No. 5-1
In the specification of No. 01808, it is said that the shape defect can be prevented by defining the amount of temperature drop of the steel sheet due to heat transfer by contact with the energizing roll.

【００１３】しかし、薄鋼板の連続焼鈍では板幅が広が
るほど、鋼板の急冷防止だけでは形状不良を防止できな
いことが明らかになってきた。形状不良の発生原因が、
鋼板急冷ばかりでなく、加熱装置内で鋼板の両端を挟持
されたまま急速加熱されることにより、鋼板の熱膨張が
拘束されることに伴う圧縮応力が鋼板にかかり、それが
高温側通電ロール部を通過する際残留応力となり、高温
側通電ロール部を通過後開放されるためと推定される。However, it has become clear that in continuous annealing of thin steel sheets, as the sheet width increases, it is not possible to prevent defective shapes only by preventing rapid cooling of the steel sheet. The cause of defective shape is
Not only the steel plate is rapidly cooled, but also the steel plate is rapidly heated while holding both ends of the steel plate in the heating device, so that a compressive stress is applied to the steel plate due to the restraint of the thermal expansion of the steel plate. It is presumed that the residual stress is generated when passing through the high temperature side and is released after passing through the high temperature side energizing roll part.

【００１４】以上のように、これまでの方法は、炉部に
おける帯状鋼板の張力が一般的に約１ｋｇ／ｍｍ² 以下
に設定されていた連続熱処理炉では、鋼板の通電加熱に
伴って発生する形状不良にすべて対応することはできな
い。As described above, according to the conventional methods, in the continuous heat treatment furnace in which the tension of the strip-shaped steel sheet in the furnace portion is generally set to about 1 kg / mm ² or less, it occurs with the electric heating of the steel sheet. Not all shape defects can be dealt with.

【００１５】そこで本発明は、加熱炉や均熱炉等と通電
加熱装置とを組み合わせて帯状金属板を連続熱処理する
際に、別個の形状矯正装置を必要とせず、形状不良を矯
正でき、通電加熱に伴う形状不良の発生も防止可能な連
続熱処理方法を提供することを目的とする。Therefore, according to the present invention, when a heating furnace, a soaking furnace or the like is combined with an electric heating apparatus to continuously heat-treat a strip-shaped metal plate, a separate shape correcting apparatus is not required, and a shape defect can be corrected and an electric current can be supplied. It is an object of the present invention to provide a continuous heat treatment method capable of preventing the occurrence of defective shapes due to heating.

【００１６】[0016]

【課題を解決するための手段】上記目的を達成するため
に、本発明は、連続熱処理炉の入側及び出側に設けた張
力付与手段により帯状金属板を一定張力に保持して加熱
帯に連続送給すると共に、その加熱帯の前及び／又は後
に設けた通電加熱装置に連続通板するようにした帯状金
属板の連続熱処理方法であって、前記通電加熱装置にお
ける低温側と高温側の通電ロール部間の帯状金属板の張
力ＵＴ（ｋｇ／ｍｍ² ）を通電ロール部のスリップ限界
以下とし、且つ、加熱温度Ｔ（℃）における帯状金属板
の降伏応力σ_y （ｋｇ／ｍｍ² ）との下記の関係式
（１）を満足する張力にすることにより帯状金属板を延
伸させ、さらに、通電加熱装置以外での帯状金属板の張
力（ＵＴ）′を０．５σ_y 以下にすることを特徴とす
る。 ０．５σ_y （Ｔ）≦ＵＴ≦２．５σ_y （Ｔ） …（１）In order to achieve the above object, the present invention provides a heating zone in which a belt-shaped metal plate is kept at a constant tension by tension applying means provided on the inlet side and the outlet side of a continuous heat treatment furnace. A continuous heat treatment method for a strip-shaped metal plate, which is continuously fed and is continuously passed through an electric heating device provided before and / or after the heating zone, wherein a low temperature side and a high temperature side of the electric heating device are provided. The tensile stress UT (kg / mm ² ) of the strip metal plate between the energizing roll parts is set to be equal to or less than the slip limit of the energizing roll part, and the yield stress σ _y (kg / mm ² ) of the strip metal plate at the heating temperature T (° C) And stretching the strip-shaped metal plate by adjusting the tension satisfying the following relational expression (1), and further setting the tension (UT) ′ of the strip-shaped metal plate other than the electric heating device to 0.5σ _y or less. Is characterized by. 0.5σ _y (T) ≦ UT ≦ 2.5σ _y (T) (1)

【００１７】また、前記の方法において、前記通電加熱
装置における低温側と高温側の通電ロール部間の帯状金
属板の張力を、溶接部通過等の非定常時に通電ロール部
の圧下力と連動させて変更することを特徴とする。In the above method, the tension of the strip-shaped metal plate between the low-temperature side and high-temperature side current-carrying roll portions of the current-carrying heating device is interlocked with the rolling-down force of the current-carrying roll portions during unsteady conditions such as when passing through a weld. It is characterized by changing it.

【００１８】[0018]

【発明の実施の形態】以下、本発明の実施の形態につい
て図面を参照して説明する。Embodiments of the present invention will be described below with reference to the drawings.

【００１９】まず、図１（ａ）において、帯状鋼板２０
を通電加熱する通電加熱装置３０は、低温側を金属製の
通電ロール３１と少なくとも外周にゴム層を有する径方
向に弾性変形可能な押えロール３２、高温側を金属製の
通電ロール３３と外周に耐熱性の薄肉金属シェルを有し
ゴム層または金属層等の弾性体を内蔵した径方向に弾性
変形可能な押えロール３４で構成する。そして、両押え
ロール３２及び３４に圧下力を付与し、両通電ロール３
１及び３３により通電する。なお、加熱方法としては、
前述したように、両通電ロール３１及び３３により鋼板
２０に直接通電する方法、或いは、環状トランスにより
鋼板２０に誘導電流を生じさせる方法を用いることがで
きる。また、両通電ロール３１及び３３をそれぞれモー
タ３５及び３６により駆動するが、これは両押えロール
３２及び３４の駆動または上下両方の駆動としてもよ
い。First, in FIG. 1A, the strip steel plate 20
An energization heating device 30 for energizing and heating the energization heating device 30 includes a metal energization roll 31 on the low temperature side and a radially elastically deformable pressing roll 32 having at least an outer periphery rubber layer, and a high temperature side on the metal energization roll 33 and the outer periphery The pressing roll 34 has a heat-resistant thin metal shell and has an elastic body such as a rubber layer or a metal layer and is elastically deformable in the radial direction. Then, a pressing force is applied to both presser rolls 32 and 34, and both energizing rolls 3
Energize with 1 and 33. As a heating method,
As described above, a method of directly energizing the steel sheet 20 with the both energizing rolls 31 and 33, or a method of generating an induced current in the steel sheet 20 with an annular transformer can be used. Further, both energizing rolls 31 and 33 are driven by motors 35 and 36, respectively, but this may be driving of both pressing rolls 32 and 34 or both upper and lower drives.

【００２０】このような通電加熱装置３０において通電
加熱を行うと、例えば図１（ｂ）に示すように、帯状鋼
板２０の低温側と高温側との間で温度差に基づく幅方向
の膨張差が生じ、それにより、降伏応力の低い高温側の
鋼板２０が座屈して幅方向に波を発生させ、張力が低い
とその波が高温側通電ロール３３の通過後に筋となって
鋼板２０に残る。When electric heating is performed in the electric heating device 30 as described above, for example, as shown in FIG. 1B, the expansion difference in the width direction between the low temperature side and the high temperature side of the strip-shaped steel sheet 20 based on the temperature difference. As a result, the steel plate 20 on the high temperature side having a low yield stress buckles to generate a wave in the width direction, and when the tension is low, the wave remains on the steel plate 20 as a streak after passing through the high temperature side energizing roll 33. .

【００２１】そこで、通電加熱の加熱終了側の高温側通
電ロール３３部で鋼板２０を延伸させながら通電加熱す
ることにより、鋼板２０の形状不良を矯正すると同時
に、通電加熱に伴う形状不良の発生も防止する。熱処理
以前で発生した耳波、中伸び等の形状不良は、鋼板２０
を一様に引き延ばすことにより容易に矯正される。その
上、通電加熱に伴う形状不良も、原因となる鋼板２０内
の残留応力が、鋼板２０を通電ロール３３と押えロール
３４とで挟持され拘束されたまま一方向に引き延ばすこ
とによって解放されるために、発生防止が可能となるの
である。Therefore, by electrically energizing the steel sheet 20 while stretching it at the high temperature side energizing roll 33 portion on the heating end side of the energizing heating, the shape defect of the steel sheet 20 is corrected and at the same time, the shape defect associated with the energizing heating occurs. To prevent. Shape defects such as selvages and medium elongation that occurred before heat treatment were
Is easily straightened by uniformly stretching. In addition, the residual stress in the steel plate 20, which causes the defective shape due to the electric current heating, is released by stretching the steel plate 20 in one direction while being clamped and constrained by the electric current roll 33 and the pressing roll 34. In addition, the occurrence can be prevented.

【００２２】この通電加熱装置における張力制御方法に
ついて図２を用いて説明する。加熱入側においては、通
電加熱部張力に基づいてトルク基準演算を行い、通電ロ
ール３１の駆動モータ３５を電流制御する。加熱出側に
おいては、テンションメータ３７による検出張力と炉張
力基準とに基づいて張力制御の値を求め、この結果と炉
部速度基準とに基づいて通電ロール３３の駆動モータ３
６を回転制御する。A tension control method in this electric heating apparatus will be described with reference to FIG. On the heating entry side, torque reference calculation is performed based on the energizing heating unit tension, and the drive motor 35 of the energizing roll 31 is current-controlled. On the heating outlet side, the tension control value is obtained based on the tension detected by the tension meter 37 and the furnace tension reference, and the drive motor 3 for the energizing roll 33 is obtained based on this result and the furnace speed reference.
6 is rotationally controlled.

【００２３】本実施形態では、ロール対を通電ロール３
１及び３３と押えロール３２及び３４との対で構成し、
鋼板２０を圧下する力と連動させて、低温側ロール３１
及び３２の対では鋼板２０の進行方向とは逆向きの張力
を与え、高温側ロール３３及び３４の対では鋼板２０の
進行方向と同方向の張力を与えることにより、図１
（ｃ）に示すように、ロール対間の張力だけをその前後
の張力に影響されることなく高く設定可能とした。In the present embodiment, the roll pair is the energizing roll 3
1 and 33 and presser rolls 32 and 34 are paired,
In conjunction with the force for rolling down the steel plate 20, the low temperature side roll 31
1 and 32 by applying a tension in the direction opposite to the traveling direction of the steel plate 20, and by applying a tension in the same direction as the traveling direction of the steel plate 20 in the pair of high temperature side rolls 33 and 34.
As shown in (c), only the tension between the roll pairs can be set high without being affected by the tension before and after the roll pair.

【００２４】ここで、物性値の異なるアルミキルド鋼板
と極低炭素鋼板とを図１と同様な装置で張力を変えて通
電加熱し、鋼板形状を観察した結果を、図３に示した。
この図から、良好な鋼板形状を得るための張力範囲を求
めることができる。即ち、張力によって鋼板の延伸され
る量は、鋼板の降伏応力に依存し、鋼板の降伏応力は鋼
板の温度と組成に大きく依存することから、加熱温度Ｔ
（℃）における鋼板の降伏応力をσ_y （Ｔ）（ｋｇ／ｍ
ｍ² ）とすると、鋼板の張力を０．５×σ_y （Ｔ）以上
にすれば、特に板厚０．５ｍｍ以下の薄鋼板を６００〜
９００℃に加熱しても、形状良好な鋼板が得られる。一
方、鋼板の張力を２．５×σ_y （Ｔ）以上にすると、過
大伸びが発生し、幅縮みが大きくなるばかりでなく、極
端な場合には板破断につながる。以上から、下記の関係
式（１）で示した形状良好な鋼板を得るための張力ＵＴ
の範囲が得られた。 ０．５σ_y （Ｔ）≦ＵＴ≦２．５σ_y （Ｔ） …（１）FIG. 3 shows the results of observing the shapes of the aluminum-killed steel sheet and the ultra-low carbon steel sheet having different physical properties by using the same apparatus as in FIG.
From this figure, the tension range for obtaining a good steel plate shape can be obtained. That is, the amount by which the steel sheet is stretched by the tension depends on the yield stress of the steel sheet, and the yield stress of the steel sheet greatly depends on the temperature and composition of the steel sheet.
Yield stress of steel sheet at (℃) σ _y (T) (kg / m
m ² ), if the tension of the steel sheet is set to 0.5 × σ _y (T) or more, a thin steel sheet with a sheet thickness of 0.5 mm or less is 600 to
A steel plate having a good shape can be obtained even when heated to 900 ° C. On the other hand, when the tension of the steel sheet is set to 2.5 × σ _y (T) or more, excessive elongation occurs, not only the width shrinkage increases but also the sheet breaks in an extreme case. From the above, the tension UT for obtaining a steel sheet having a good shape shown by the following relational expression (1)
A range of is obtained. 0.5σ _y (T) ≦ UT ≦ 2.5σ _y (T) (1)

【００２５】ここで、鋼板をピンチする力（圧下力）と
連動させて張力を変化させるのは、圧下力と無関係に張
力だけを高くすると、鋼板とロール間でスリップが発生
するようになり、また、逆に充分に圧下した状態で張力
だけを下げると、鋼板に絞りや筋が発生するからであ
る。Here, the tension is changed by interlocking with the force (rolling down force) for pinching the steel sheet. If only the tension is increased irrespective of the rolling down force, slip occurs between the steel sheet and the roll. On the contrary, if only the tension is lowered in a sufficiently reduced state, the steel sheet will be drawn or streaked.

【００２６】このため、ロール対間での鋼板の張力ＵＴ
を、通電ロール部でのスリップ限界以下として、上記の
関係式（１）満足するような条件、好ましくは最低でも
単位断面積当たり２ｋｇ／ｍｍ² 以上に高め、通電加熱
装置以外での張力（ＵＴ）′を０．５σ_y 以下として、
形状不良材の常温付近での通板時には、見かけの形状を
ほぼフラットにすると共に、加熱時には、鋼板に微少な
塑性変形を与えて座屈により発生する幅方向の波を低減
させることが必要である。Therefore, the tension UT of the steel sheet between the pair of rolls
Is set to be equal to or less than the slip limit in the energizing roll portion, the condition satisfying the above relational expression (1), preferably at least 2 kg / mm ² or more per unit cross-sectional area, and the tension (UT ) ′ Is 0.5σ _y or less,
It is necessary to make the apparent shape almost flat when passing a poorly shaped material near room temperature at the same time, and to reduce the waves in the width direction caused by buckling by giving a slight plastic deformation to the steel sheet when heating. is there.

【００２７】ところで、帯状鋼板の溶接部で通電を切っ
たような常温に近い状態でも、鋼板が耳波材、中伸び材
等の形状不良材の場合には、高温側通電ロールの通過後
に前述と同様な筋を発生したり、酷い場合には、鋼板に
絞りが発生する。By the way, even if the steel plate is a shape-defective material such as a corrugated material or a mid-stretch material even if the current is close to room temperature when the current is cut off at the welded portion of the strip-shaped steel sheet, the above-mentioned operation is performed after passing through the high-temperature side energizing roll. The same streaks are generated, and in severe cases, the steel sheet is drawn.

【００２８】そこで、非定常時の張力と圧下力の変更方
法について図４を用いて説明する。溶接点通過の際に
は、溶接点がロール部を通過する前に、通電を停止し、
圧下力を開放すると共に張力を炉部と同じ値にする。そ
して、溶接点がロール部を通過した後に、圧下力を付与
すると共に張力を所定値に戻し、通電を再開する。これ
により、鋼板とロール間でのスリップの発生を防止し、
鋼板にスリ疵が入ることを防止することができる。Therefore, a method of changing the tension and the rolling force in the non-steady state will be described with reference to FIG. When passing the welding point, stop the energization before the welding point passes through the roll part,
The rolling force is released and the tension is set to the same value as the furnace section. Then, after the welding point passes through the roll portion, the rolling force is applied, the tension is returned to a predetermined value, and the energization is restarted. This prevents the occurrence of slip between the steel plate and the roll,
It is possible to prevent scratches from entering the steel plate.

【００２９】[0029]

【実施例】図１と同様な通電加熱装置において、圧下力
３ｋｇ／ｍｍ、張力１ｋｇ／ｍｍ² として、板厚０．２
ｍｍ、板幅９００ｍｍの鋼板を７５０℃に加熱したとこ
ろ、高温側ロール入側の板幅方向に座屈による波が発生
し、高温側ロール出側の鋼板の幅方向に筋が発生した。EXAMPLE An electric heating apparatus similar to that shown in FIG. 1 was used, with a rolling force of 3 kg / mm and a tension of 1 kg / mm ² , and a plate thickness of 0.2.
When a steel plate having a width of 900 mm and a plate width of 900 mm was heated to 750 ° C., a wave due to buckling was generated in the plate width direction on the high temperature side roll entrance side, and streaks were generated in the width direction of the steel plate on the high temperature side roll exit side.

【００３０】これに対して、通電ロールのトルクを増加
させ、張力を４ｋｇ／ｍｍ² に増加したところ、ロール
でのスリップもなく、高温側ロール出側の筋の発生もな
くなり、良好な板形状が得られた。On the other hand, when the torque of the energizing roll was increased and the tension was increased to 4 kg / mm ² , there was no slip on the roll and no streak on the high temperature side of the roll disappeared, resulting in a good plate shape. was gotten.

【００３１】また、溶接部の通過の際に一旦押えロール
を開放し、再度圧下する場合に、圧下力の増加と共に張
力を所定の４ｋｇ／ｍｍ² まで増加したところ、急峻度
１％程度の耳波材であったが、冷間における絞りや筋の
発生もなく、安定した通板ができた。Further, when the pressing roll is once opened at the time of passing through the welded part and then repressed, the tension is increased to a predetermined value of 4 kg / mm ² with an increase in the pressing force, and the steepness is about 1%. Although it was a corrugated material, stable passage was possible without cold drawing or streaking.

【００３２】なお、通電加熱装置の後方の炉部の張力は
約０．５ｋｇ／ｍｍ² で安定しており、板破断、ヒート
バックル等は発生しなかった。The tension of the furnace portion behind the electric heating device was stable at about 0.5 kg / mm ² , and no plate breakage or heat buckle occurred.

【００３３】[0033]

【発明の効果】以上説明したように、本発明によれば、
張力を高く設定できない加熱炉や均熱炉等と通電加熱装
置との組み合わせにおいて、通電加熱装置の低温側と高
温側の通電ロール部間における帯状金属板の張力だけを
高く設定することにより、別個の形状矯正装置を必要と
せず、帯状金属板を加熱すると同時に形状矯正すること
が可能となり、加熱後の板形状として筋のない良好なも
のが得られる。また、耳波材、中伸び材等の形状不良材
の常温付近での通板性も良好となる。As described above, according to the present invention,
In a combination of a heating furnace or soaking furnace that cannot set a high tension with an electric heating device, by setting only the tension of the strip-shaped metal plate between the low-temperature side and high-temperature side of the electric heating device to be high, It is possible to heat the strip-shaped metal plate and straighten the shape at the same time without requiring the shape-correcting device, and a good plate shape without heating can be obtained after heating. In addition, the passability of poorly shaped materials such as selvages and mid-stretch materials at around room temperature is also improved.

【図面の簡単な説明】[Brief description of the drawings]

【図１】本発明の実施の形態による方法において、
（ａ）は通電加熱装置の例を示す図、（ｂ）は帯状鋼板
の板幅の膨張を示す図、（ｃ）は張力パターンを示す図
である。FIG. 1 shows a method according to an embodiment of the present invention,
(A) is a figure which shows the example of an electric heating apparatus, (b) is a figure which shows expansion of the board width of a strip | belt-shaped steel plate, (c) is a figure which shows a tension pattern.

【図２】実施形態における通電加熱装置の張力制御方法
を説明する図であるFIG. 2 is a diagram illustrating a tension control method of an electric heating device according to an embodiment.

【図３】実施形態における帯状鋼板の張力と降伏応力と
の関係を示す図である。FIG. 3 is a diagram showing a relationship between tension and yield stress of the strip steel sheet in the embodiment.

【図４】実施形態における非定常時の張力と圧下力の変
更方法を説明する図である。FIG. 4 is a diagram illustrating a method of changing tension and rolling force at a non-steady state in the embodiment.

【図５】連続焼鈍炉の従来例を示す図である。FIG. 5 is a diagram showing a conventional example of a continuous annealing furnace.

【図６】通電加熱装置を連続熱処理炉の途中に組み込ん
だ従来例を示す図である。FIG. 6 is a view showing a conventional example in which an electric heating device is incorporated in the middle of a continuous heat treatment furnace.

【符号の説明】[Explanation of symbols]

４ 予熱炉 ５ 加熱炉 ６ 均熱炉 ７ 徐冷帯 １８ 炉入側の張力付与用ブライドル １９ 炉出側の張力付与用ダンサーロール ２０ 帯状鋼板 ３０ 通電加熱装置 ３１ 加熱入側の通電ロール ３２ 加熱入側の押えロール ３３ 加熱出側の通電ロール ３４ 加熱出側の押えロール 4 preheating furnace 5 heating furnace 6 soaking furnace 7 slow cooling zone 18 bridle for tension application on the furnace entry side 19 dancer roll for tension application on the exit side of furnace 20 strip steel plate 30 energization heating device 31 energization roll on the heating entry side 32 heating entry Side holding roll 33 Heating outlet side energizing roll 34 Heating outlet side holding roll

Claims (2)

【特許請求の範囲】[Claims] 【請求項１】 連続熱処理炉の入側及び出側に設けた張
力付与手段により帯状金属板を一定張力に保持して加熱
帯に連続送給すると共に、その加熱帯の前及び／又は後
に設けた通電加熱装置に連続通板するようにした帯状金
属板の連続熱処理方法であって、 前記通電加熱装置における低温側と高温側の通電ロール
部間の帯状金属板の張力ＵＴ（ｋｇ／ｍｍ² ）を通電ロ
ール部のスリップ限界以下とし、且つ、加熱温度Ｔ
（℃）における帯状金属板の降伏応力σ_y （ｋｇ／ｍｍ
² ）との下記の関係式（１）を満足する張力にすること
により帯状金属板を延伸させ、さらに、通電加熱装置以
外での帯状金属板の張力（ＵＴ）′を０．５σ_y 以下に
することを特徴とする帯状金属板の連続熱処理方法。 ０．５σ_y （Ｔ）≦ＵＴ≦２．５σ_y （Ｔ） …（１）1. A belt-shaped metal plate is continuously fed to a heating zone while being kept at a constant tension by tension applying means provided on the inlet side and the outlet side of a continuous heat treatment furnace, and is provided before and / or after the heating zone. A continuous heat treatment method for a strip-shaped metal plate, which is adapted to be continuously passed through an energization heating device, wherein the tension UT (kg / mm ²⁾ of the strip-shaped metal plate between the low-temperature side and the high-temperature side energizing rolls in the energization heating device. ) Is less than or equal to the slip limit of the energizing roll portion, and the heating temperature T
Yield stress σ _y (kg / mm) of strip metal plate at (℃)
² ) With the tension that satisfies the following relational expression (1) with (1), the strip-shaped metal plate is stretched, and the tension (UT) ′ of the strip-shaped metal plate other than the electric heating device is set to 0.5σ _y or less. A continuous heat treatment method for a strip-shaped metal plate, which comprises: 0.5σ _y (T) ≦ UT ≦ 2.5σ _y (T) (1) 【請求項２】 前記通電加熱装置における低温側と高温
側の通電ロール部間の帯状金属板の張力を、溶接部通過
等の非定常時に通電ロール部の圧下力と連動させて変更
することを特徴とする請求項１記載の帯状金属板の連続
熱処理方法。2. The tension of the strip-shaped metal plate between the low-temperature side and high-temperature side energizing roll parts of the energizing heating device is changed in conjunction with the rolling force of the energizing roll part during non-steady state such as passing through a welding part. The continuous heat treatment method for a strip-shaped metal plate according to claim 1.