JP5217542B2 - Continuous annealing method and continuous annealing equipment for steel strip with Curie point - Google Patents

Continuous annealing method and continuous annealing equipment for steel strip with Curie point Download PDF

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JP5217542B2
JP5217542B2 JP2008070241A JP2008070241A JP5217542B2 JP 5217542 B2 JP5217542 B2 JP 5217542B2 JP 2008070241 A JP2008070241 A JP 2008070241A JP 2008070241 A JP2008070241 A JP 2008070241A JP 5217542 B2 JP5217542 B2 JP 5217542B2
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heating
steel strip
frequency induction
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curie point
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重信 古賀
大照 持永
誠 安宅
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Nippon Steel Corp
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Nippon Steel and Sumitomo Metal Corp
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Priority to KR1020097018319A priority patent/KR101185597B1/en
Priority to CN2008800111153A priority patent/CN101652485B/en
Priority to BRPI0811253-3A2A priority patent/BRPI0811253A2/en
Priority to RU2009140785/02A priority patent/RU2414513C1/en
Priority to US12/450,650 priority patent/US20100101690A1/en
Priority to EP08740220.2A priority patent/EP2133436B1/en
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Description

本発明は、キュリー点（Curie Temperature：Ｔｃとも表記する。）を有する鋼帯の連続焼鈍方法及び連続焼鈍設備に関し、特に、キュリー点近傍で昇温速度を一定に制御するために用いて好適な技術に関するものである。なお、本発明の連続焼鈍方法及び連続焼鈍設備が処理対象とするキュリー点を有する鋼帯としては、Ｓｉ≦４．５質量％を含有する方向性電磁鋼板等が例示できる。   The present invention relates to a continuous annealing method and a continuous annealing facility for a steel strip having a Curie temperature (also referred to as Curie Temperature: Tc), and is particularly suitable for use in controlling the temperature rising rate in the vicinity of the Curie temperature. It is about technology. In addition, as the steel strip having the Curie point to be processed by the continuous annealing method and the continuous annealing equipment of the present invention, a grain-oriented electrical steel sheet containing Si ≦ 4.5 mass% can be exemplified.

鋼帯などの金属帯の連続焼鈍では、一般に、加熱温度、加熱時間、加熱速度等が厳密に管理されている。その中でも、例えば、変圧器その他の電気機器の鉄心としての用途に好適な低鉄損方向性電磁鋼板の製造過程における脱炭焼鈍工程のように、厳格な昇温速度管理が求められる場合がある。   In continuous annealing of a metal strip such as a steel strip, the heating temperature, the heating time, the heating rate, etc. are generally strictly controlled. Among them, for example, strict heating rate control may be required as in the decarburization annealing process in the manufacturing process of the low iron loss directional electrical steel sheet suitable for use as an iron core of a transformer or other electrical equipment. .

方向性電磁鋼板の製造では、（ａ）脱炭焼鈍する際の昇温過程において、鋼板が歪回復・再結晶を迎える鋼板温度が５５０℃からキュリー点近傍に存在する間、とりわけ、キュリー点近傍に存在する間、に一定の昇温速度で加熱することが重要である。この領域を外れると、脱炭焼鈍後の粒組織は｛１１１｝面の比率が大きくなり、結果として、磁性の低下を招くという問題が発生する。また、（ｂ）加熱速度のばらつきによる皮膜の劣化を招くという問題等が発生する。   In the manufacture of grain-oriented electrical steel sheets, (a) in the temperature rising process during decarburization annealing, the steel sheet temperature at which the steel sheet undergoes strain recovery and recrystallization is present in the vicinity of the Curie point from 550 ° C. It is important to heat at a constant rate of heating while it is present. Outside this region, the grain structure after decarburization annealing has a large ratio of {111} planes, and as a result, there arises a problem of causing a decrease in magnetism. In addition, (b) a problem that the film is deteriorated due to variations in the heating rate occurs.

このような焼鈍昇温速度の管理の範囲に関する発明として、特許文献１には、方向性電磁鋼板の脱炭焼鈍に際し、冷間圧延された鋼帯を２３０℃／秒以上の加熱速度で７０５℃以上の温度へ急速加熱することにより鉄損を改善できる発明が開示されており、その実施例２、３では、キュリー点７４６℃へ１１００ないし１２００℃／秒の加熱速度で加熱する特別の電磁誘導加熱コイル（基本周波数：４５０ｋＨｚ）の使用が開示されている。   As an invention relating to the management range of such annealing temperature increase rate, Patent Document 1 discloses that a steel strip that has been cold-rolled is 705 ° C. at a heating rate of 230 ° C./second or more during decarburization annealing of a grain-oriented electrical steel sheet. Inventions that can improve iron loss by rapid heating to the above temperature are disclosed. In Examples 2 and 3, a special electromagnetic induction for heating to a Curie point of 746 ° C. at a heating rate of 1100 to 1200 ° C./sec. The use of a heating coil (fundamental frequency: 450 kHz) is disclosed.

また、鋼板の連続焼鈍方法に関し、先行材から焼鈍条件の異なる後行材への焼鈍条件の変更を円滑に行えるようにするために、条件変更部の板温を変更するために誘導加熱装置を活用する発明が特許文献２で開示されている。   In addition, regarding the continuous annealing method for steel sheets, an induction heating device is used to change the plate temperature of the condition change part in order to smoothly change the annealing conditions from the preceding material to the subsequent material having different annealing conditions. The invention to be utilized is disclosed in Patent Document 2.

また、特許文献３には、鋼板の複数の誘導加熱装置を用いた焼戻しに関し、装置の入側の鋼材の先頭部分の温度を実測し、加熱に必要な電力を決定して電力設定する発明、あるいは、誘導加熱装置の間に温度計を設置し、鋼材温度を実測し、実測した鋼材温度に基いて電力設定値を補正することにより鋼板の長手方向の材質均一性を図るようにする発明が開示されている。   In addition, Patent Document 3 relates to tempering using a plurality of induction heating devices for a steel sheet, actually measuring the temperature of the leading portion of the steel material on the entry side of the device, determining the power required for heating, and setting the power, Alternatively, an invention is provided in which a thermometer is installed between the induction heating devices, the steel material temperature is measured, and the power uniformity is corrected based on the measured steel temperature to achieve material uniformity in the longitudinal direction of the steel plate. It is disclosed.

また、特許文献４には、厚鋼板製造プロセスにおいて加速冷却を採用する場合に、その高冷却性のために発生し易い温度むらが引き起こす鋼板の機械的特性のばらつきや形状不良、さらには残留応力による条切りキャンバー等の問題を、加速冷却後の鋼板の加熱目標温度を鋼材の磁気変態温度（キュリー点）、または７００℃〜７６０℃とする誘導加熱装置を用いた熱処理を施し、鋼板内の温度均一性を高めてから熱間矯正することにより、解決する発明が開示されている。   Further, in Patent Document 4, when accelerated cooling is employed in a thick steel plate manufacturing process, variations in the mechanical properties and shape defects of the steel plate caused by temperature irregularities that are likely to occur due to its high cooling property, and further residual stress. In the steel plate, the heat treatment using an induction heating device in which the target heating temperature of the steel plate after accelerated cooling is set to the magnetic transformation temperature (Curie point) of the steel material or 700 ° C. to 760 ° C. An invention to be solved by hot correction after increasing temperature uniformity is disclosed.

特公平０６−０５１８８７号公報Japanese Patent Publication No. 06-051887 特開２００３−３２８０３９号公報JP 2003-328039 A 特開２００５−１２０４０９号公報JP 2005-120409 A 特開２００６−２０６９２７号公報JP 2006-206927 A

しかしながら、上記特許文献１に記載の発明では、電磁誘導加熱による急速加熱を電磁鋼板の脱炭焼鈍のキュリー点までの加熱に適用することで、電磁鋼板の鉄損を改善できることが開示されているが、誘導加熱装置による鋼材の温度制御方案、あるいは、鋼材の昇温速度の制御方案については何ら開示されていない。   However, the invention described in Patent Document 1 discloses that the iron loss of the electrical steel sheet can be improved by applying rapid heating by electromagnetic induction heating to heating up to the Curie point of decarburization annealing of the electrical steel sheet. However, there is no disclosure of a steel material temperature control method using an induction heating device or a steel material temperature increase rate control method.

また、上記特許文献２に記載の発明は、先行材から焼鈍条件の異なる後行材への焼鈍条件の変更を円滑に行うことを目的とするものであって、鋼材の温度制御方案については何ら具体的に記載されていない、あるいは、鋼材の昇温速度の制御方案については何ら開示されていない。   In addition, the invention described in Patent Document 2 is intended to smoothly change the annealing condition from the preceding material to the succeeding material having different annealing conditions, and there is nothing about the temperature control method of the steel material. It is not specifically described, or nothing is disclosed about a method for controlling the rate of temperature rise of the steel material.

また、上記特許文献３に記載の発明では、誘導加熱装置の入口、及び、誘導加熱装置の間に設置された温度計により鋼材の温度を測定し、必要な昇熱温度を得るための電力設定を行うものであって、キュリー点近傍の昇温速度を制御することに関しては、なんら開示されていない。   Further, in the invention described in Patent Document 3, the power setting for obtaining the necessary heat-up temperature by measuring the temperature of the steel material with the thermometer installed between the inlet of the induction heating device and the induction heating device. Nothing is disclosed regarding controlling the temperature rise rate near the Curie point.

また、上記特許文献４に記載の発明では、誘導加熱装置の加熱目標温度を、鋼材の磁気変態温度（キュリー点）または７００℃〜７６０℃とする熱処理を施せば、鋼板内の温度均一性を高めることができることが開示されているが、鋼材の温度制御方案については何ら開示されていない。   Further, in the invention described in Patent Document 4, if the heat target temperature of the induction heating device is set to a magnetic transformation temperature (Curie point) of steel material or 700 ° C. to 760 ° C., the temperature uniformity in the steel plate is increased. Although it is disclosed that the temperature can be increased, there is no disclosure about a temperature control method of the steel material.

本発明は前述の問題点に鑑み、キュリー点を有する鋼帯を、キュリー点近傍の昇温速度を長手方向に極めて均一に加熱できるようにすることを目的としている。   The present invention has been made in view of the above-described problems, and an object of the present invention is to make it possible to heat a steel strip having a Curie point extremely uniformly in the longitudinal direction at a temperature rising rate in the vicinity of the Curie point.

本発明のキュリー点を有する鋼帯の連続焼鈍方法は、加熱帯、均熱帯及び冷却帯、または加熱帯、均熱帯、窒化帯及び冷却帯からなり、前記加熱帯が第１加熱帯、第２加熱帯及び第３加熱帯に区分されている連続焼鈍設備での、キュリー点を有する鋼帯の連続焼鈍方法であって、
前記第１加熱帯において、前記鋼帯を５００℃以上、キュリー点Ｔｃ（℃）−５０℃未満まで加熱する第１加熱工程と、
前記第２加熱帯において、前記第１加熱帯で加熱された鋼帯をキュリー点Ｔｃ−３０℃ないしキュリー点Ｔｃ−５℃の温度領域まで、上流のソレノイドコイル式高周波誘導加熱装置及び下流のソレノイドコイル式高周波誘導加熱装置により加熱する第２加熱工程と、
前記第３加熱帯において、前記第２加熱帯で加熱された鋼帯をキュリー点を超える処理目標温度まで加熱する第３加熱工程と、
前記第２加熱工程の加熱動作を制御する昇温速度制御工程とを有し、
前記昇温速度制御工程は、前記上流のソレノイドコイル式高周波誘導加熱装置に電力を出力する電力出力部と、前記下流のソレノイドコイル式高周波誘導加熱装置に電流を出力する電流出力部とを制御し、
前記下流のソレノイドコイル式高周波誘導加熱装置での実績出力電力値に基いて前記上流のソレノイドコイル式高周波誘導加熱装置の出力電力値を制御するようにしたことを特徴とする。 The method for continuously annealing a steel strip having a Curie point according to the present invention comprises a heating zone, a soaking zone and a cooling zone, or a heating zone, a soaking zone, a nitriding zone and a cooling zone, wherein the heating zone is a first heating zone, a second soaking zone. A continuous annealing method for a steel strip having a Curie point in a continuous annealing facility divided into a heating zone and a third heating zone,
In the first heating zone, a first heating step of heating the steel strip to 500 ° C. or higher and a Curie point Tc (° C.) to less than −50 ° C .;
In the second heating zone, an upstream solenoid coil type high-frequency induction heating device and a downstream solenoid are heated up to a temperature range of Curie point Tc-30 ° C to Curie point Tc-5 ° C. A second heating step of heating by a coil type high frequency induction heating device;
In the third heating zone, a third heating step of heating the steel strip heated in the second heating zone to a processing target temperature exceeding the Curie point;
A heating rate control step for controlling the heating operation of the second heating step,
The heating rate control step controls a power output unit that outputs power to the upstream solenoid coil type high frequency induction heating device and a current output unit that outputs current to the downstream solenoid coil type high frequency induction heating device. ,
The output power value of the upstream solenoid coil type high frequency induction heating device is controlled based on the actual output power value of the downstream solenoid coil type high frequency induction heating device.

本発明のキュリー点を有する鋼帯の連続焼鈍設備は、加熱帯、均熱帯及び冷却帯、または加熱帯、均熱帯、窒化帯及び冷却帯からなり、前記加熱帯が第１加熱帯、第２加熱帯及び第３加熱帯に区分されているキュリー点を有する鋼帯の連続焼鈍設備であって、
前記第１加熱帯において、前記鋼帯を５００℃以上、キュリー点Ｔｃ（℃）−５０℃未満まで加熱する第１加熱手段と、
前記第２加熱帯において、前記第１加熱帯で加熱された鋼帯をキュリー点Ｔｃ−３０℃ないしキュリー点Ｔｃ−５℃の温度領域まで、上流のソレノイドコイル式高周波誘導加熱装置及び下流のソレノイドコイル式高周波誘導加熱装置により加熱する第２加熱手段と、
前記第３加熱帯において、前記第２加熱帯で加熱された鋼帯をキュリー点を超える処理目標温度まで加熱する第３加熱手段と、
前記第２加熱手段の加熱動作を制御する昇温速度制御装置とを有し、
前記昇温速度制御装置は、前記上流のソレノイドコイル式高周波誘導加熱装置に電力を出力する電力出力部と、前記下流のソレノイドコイル式高周波誘導加熱装置に電流を出力する電流出力部とを有し、
前記下流のソレノイドコイル式高周波誘導加熱装置での実績出力電力値に基いて前記上流のソレノイドコイル式高周波誘導加熱装置の出力電力値を制御するようにしたことを特徴とする。 The continuous annealing equipment for a steel strip having a Curie point according to the present invention comprises a heating zone, a soaking zone and a cooling zone, or a heating zone, a soaking zone, a nitriding zone and a cooling zone, wherein the heating zone is a first heating zone, a second soaking zone. A steel strip continuous annealing facility having a Curie point divided into a heating zone and a third heating zone,
In the first heating zone, a first heating means for heating the steel strip to 500 ° C. or higher and a Curie point Tc (° C.) to less than −50 ° C .;
In the second heating zone, an upstream solenoid coil type high-frequency induction heating device and a downstream solenoid are heated up to a temperature range of Curie point Tc-30 ° C to Curie point Tc-5 ° C. A second heating means for heating by a coil type high frequency induction heating device;
In the third heating zone, a third heating means for heating the steel strip heated in the second heating zone to a processing target temperature exceeding the Curie point;
A heating rate control device for controlling the heating operation of the second heating means,
The temperature increase rate control device includes a power output unit that outputs power to the upstream solenoid coil type high frequency induction heating device, and a current output unit that outputs current to the downstream solenoid coil type high frequency induction heating device. ,
The output power value of the upstream solenoid coil type high frequency induction heating device is controlled based on the actual output power value of the downstream solenoid coil type high frequency induction heating device.

本発明によれば、キュリー点を有する鋼帯のキュリー点近傍での鋼帯の昇温速度を長手方向に極めて均一に行うことができるようにすることができる。これにより、特に、鋼板の昇温速度に厳格な制御及び均一性が求められる方向性珪素鋼板の冷間圧延された鋼帯の連続脱炭焼焼鈍では、その昇温速度の厳格な範囲での達成や均一化による品質改善効果が大きく、安定した製品を製造できるようにすることができる。   ADVANTAGE OF THE INVENTION According to this invention, the temperature increase rate of the steel strip in the vicinity of the Curie point of the steel strip which has a Curie point can be performed very uniformly in a longitudinal direction. As a result, particularly in continuous decarburization annealing of cold-rolled steel strips of directional silicon steel sheets that require strict control and uniformity in the temperature increase rate of the steel sheet, the temperature increase rate is achieved in a strict range. It is possible to produce a stable product with a large quality improvement effect due to uniformization.

以下、本発明を実施するための最良の形態を、本発明の効果が特に大きい方向性珪素鋼板の製造を例にして説明する。なお、本発明が方向性珪素鋼板に限定されないことは言うまでもない。   Hereinafter, the best mode for carrying out the present invention will be described by taking as an example the production of a grain-oriented silicon steel sheet in which the effects of the present invention are particularly significant. In addition, it cannot be overemphasized that this invention is not limited to a grain-oriented silicon steel plate.

図１は、方向性珪素鋼の仕上冷延板を脱炭焼鈍（焼鈍分離剤の塗布を含む）するための代表的な連続熱処理設備の概略的な構成例を説明する等角投影図である。
連続熱処理設備ラインの主な要素は、仕上冷間圧延加工された方向性珪素鋼のコイル状の鋼帯６０を装荷して、そこから巻出していくためのペイオフリール１を有する。 FIG. 1 is an isometric view illustrating a schematic configuration example of a typical continuous heat treatment facility for decarburizing annealing (including application of an annealing separator) on a finish cold-rolled sheet of directional silicon steel. .
The main elements of the continuous heat treatment equipment line have a payoff reel 1 for loading and unwinding a coiled steel strip 60 of directional silicon steel that has been finish cold rolled.

また、鋼帯６０の先尾端部を切断して溶接のための準備をするための入側剪断機２、鋼帯６０の端部を連続的に結合するための溶接機３、鋼帯６０を溶接する準備、及び溶接中に入側洗浄装置１１、炉部１２を減速・停止することなく通板可能とするために鋼帯６０を貯留する入側ストレージルーパー４を有する。   Moreover, the entrance side shearing machine 2 for cutting the tail end part of the steel strip 60 and preparing for welding, the welding machine 3 for continuously joining the end parts of the steel strip 60, and the steel strip 60 , And the inlet side storage looper 4 for storing the steel strip 60 so that the inlet side cleaning device 11 and the furnace part 12 can be passed without decelerating and stopping during welding.

さらに、鋼帯６０の表面を洗浄し、圧延油や鉄分等の汚れを除去するための入側洗浄装置１１、鋼帯６０を脱炭焼鈍するために用いられる加熱・均熱・冷却領域からなる炉部１２、コイルの再巻きつけが完了して出側剪断機６が作動している時に、鋼帯６０が入側洗浄装置１１、炉部１２を減速停止することなく通板可能とするために、鋼帯６０を貯留する出側ストレージルーパー５を有する。   Furthermore, it comprises an inlet side cleaning device 11 for cleaning the surface of the steel strip 60 and removing dirt such as rolling oil and iron, and a heating / soaking / cooling region used for decarburizing and annealing the steel strip 60. To allow the steel strip 60 to pass through the entrance side cleaning device 11 and the furnace section 12 without decelerating and stopping when the furnace section 12 and the coil rewinding are completed and the exit side shearing machine 6 is operating. The outlet storage looper 5 that stores the steel strip 60 is provided.

また、焼鈍された鋼帯６０の表面を洗浄し、炉内汚れを除去するための出側洗浄装置１３、焼鈍分離剤塗布装置１４、焼鈍分離剤乾燥装置１５、出側剪断機６、及び鋼帯６０をコイル状に再巻き付けするためのテンションリール７等を有している。また、炉部１２の動作を制御する昇温速度制御装置１００を有している。   Moreover, the exit side washing | cleaning apparatus 13, the annealing separator application | coating apparatus 14, the annealing separator drying apparatus 15, the exit side shearing machine 6, and steel for washing | cleaning the surface of the annealed steel strip 60 and removing a dirt in a furnace are performed. A tension reel 7 or the like for re-wrapping the belt 60 in a coil shape is provided. Moreover, it has the temperature increase rate control apparatus 100 which controls operation | movement of the furnace part 12. As shown in FIG.

このような装置によって構成された連続熱処理設備ラインにおいて、焼鈍分離剤乾燥装置１５は、熱慣性の低い炉材と直火バーナーから構成される高応答性の炉構成となっており、出側剪断機６が作動中におけるやむを得ない場合に発生する鋼帯６０の停止・減速に迅速に対応できる構造となっている。   In the continuous heat treatment equipment line constituted by such an apparatus, the annealing separator drying apparatus 15 has a highly responsive furnace structure composed of a furnace material with low thermal inertia and an open flame burner, The structure is such that the steel strip 60 can be stopped and decelerated quickly when the machine 6 is inevitable during operation.

また、炉部１２の前後での鋼帯６０の張力は、テンションメータ４１、４２で測定される。また、焼鈍分離剤乾燥装置１５での鋼帯６０の張力は、テンションメータ４３で測定される。各テンションメータ４１、４２及び４３の測定結果は、通過するブライドルロール２３〜２６にフィードバックされ、ブライドルロール前後の鋼帯６０の張力が確保されている。なお、出側洗浄装置１３は、炉部１２における鋼帯６０の汚れが僅少であるときは、必ずしも設置する必要はない。方向性珪素鋼の仕上冷延板は、上記のラインで脱炭焼鈍（焼鈍分離剤の塗布を含む）された後、高温焼鈍され、さらに、平滑化焼鈍が施され、最終製品となる。   Further, the tension of the steel strip 60 before and after the furnace section 12 is measured by tension meters 41 and 42. Further, the tension of the steel strip 60 in the annealing separator drying device 15 is measured by a tension meter 43. The measurement results of the tension meters 41, 42 and 43 are fed back to the passing bridle rolls 23 to 26, and the tension of the steel strip 60 before and after the bridle roll is ensured. The outlet side cleaning device 13 is not necessarily installed when the steel strip 60 in the furnace section 12 is very dirty. The finished cold-rolled sheet of directional silicon steel is decarburized and annealed (including application of an annealing separator) in the above-mentioned line, then is subjected to high-temperature annealing, and is further subjected to smooth annealing and becomes a final product.

図２は、炉部１２の基本的な構成例を模式的に示す図である。
基本的な構成の炉部１２Ａは、一般的に、ラジアントチューブ加熱方式による加熱領域３１、電気ヒータ加熱による均熱領域３２、電気ヒータ加熱による窒化領域３３及び冷却領域３４から構成されている。加熱領域３１には、加熱途中の板温を監視するための板温計３６、３７、３８が設置されている。 FIG. 2 is a diagram schematically illustrating a basic configuration example of the furnace unit 12.
The furnace section 12A having a basic configuration generally includes a heating area 31 by a radiant tube heating method, a soaking area 32 by electric heater heating, a nitriding area 33 by electric heater heating, and a cooling area 34. In the heating region 31, plate thermometers 36, 37, and 38 are installed for monitoring the plate temperature during heating.

入側洗浄装置１１で表面洗浄された鋼帯６０は、ラジアントチューブ方式による加熱領域３１で加熱され、脱炭温度約８２０℃まで加熱され、電気ヒータ加熱による均熱帯３２で脱炭焼鈍される。   The steel strip 60 whose surface has been cleaned by the inlet side cleaning device 11 is heated in the heating region 31 by the radiant tube method, heated to a decarburization temperature of about 820 ° C., and decarburized and annealed in the soaking zone 32 by the electric heater heating.

ラジアントチューブ方式による加熱領域３１では、鋼帯６０は脱炭障害とならないように加熱されており、加熱領域途中に設置された板温計３６、３７、及び加熱領域の出側の板温計３８を監視しながら炉の温度を制御している。また、最近、この板温計３６、３７、３８の測定値を自動監視しながら、加熱領域の炉を自動制御する方式もとられている。   In the heating area 31 by the radiant tube method, the steel strip 60 is heated so as not to obstruct decarburization, and plate thermometers 36 and 37 installed in the middle of the heating area, and a plate thermometer 38 on the exit side of the heating area. The furnace temperature is controlled while monitoring. Recently, a method of automatically controlling the furnace in the heating region while automatically monitoring the measured values of the plate thermometers 36, 37, and 38 has been adopted.

図３（ａ）及び（ｂ）に、前述した基本的な構成の炉部１２Ａを図１に示した連続熱処理設備ラインに設けて、方向性電磁鋼板の脱炭焼鈍における、板温計３６、３７の位置での鋼帯コイル１本分の長手方向の温度分布の一例を示す。   3 (a) and 3 (b), the thermometer 36A in the decarburization annealing of the grain-oriented electrical steel sheet is provided in the continuous heat treatment equipment line shown in FIG. An example of the temperature distribution of the longitudinal direction for one steel strip coil in the position of 37 is shown.

前述した基本的な構成の炉部１２Ａでは、板温計３６、３７の測定値を自動監視しながら、加熱領域の炉を自動制御する方式が採られているにもかかわらず、図３（ａ）に示すように加熱領域入側の板温計３６の長手方向の板温は変動している。また、図３（ｂ）に示すように、途中部の板温計３７での鋼帯６０の長手方向の板温は変動している、特に、コイルの両端は大きく長期にわたり変動している。それに伴い、鋼帯６０の昇温速度も大きく変動している。   In the furnace section 12A having the above-described basic configuration, the method of automatically controlling the furnace in the heating region while automatically monitoring the measured values of the plate thermometers 36 and 37 is adopted. ), The plate temperature in the longitudinal direction of the plate thermometer 36 on the heating region entry side fluctuates. Further, as shown in FIG. 3B, the plate temperature in the longitudinal direction of the steel strip 60 at the plate thermometer 37 in the middle part varies, and particularly, both ends of the coil vary greatly over a long period of time. Along with this, the rate of temperature increase of the steel strip 60 also varies greatly.

コイルの両端の変動は、基本的な構成の炉部１２Ａの熱慣性が大きく、この変動を抑制することは困難であったと考えられる。このような変動は、結果として、この後の一次再結晶組織に影響し、結果として２次再結晶組織での組織の配向性が低下するとともに、鋼帯６０の脱炭反応を含む表面の反応に大きく影響し、鋼帯６０長手方向の品質変動、例えば、磁性不良や皮膜欠陥等の品質障害を招いていた。   It is considered that the fluctuation at both ends of the coil has a large thermal inertia of the furnace section 12A having the basic configuration, and it has been difficult to suppress this fluctuation. Such fluctuations affect the subsequent primary recrystallized structure as a result, and as a result, the orientation of the structure in the secondary recrystallized structure decreases, and the reaction of the surface including the decarburization reaction of the steel strip 60 occurs. The quality fluctuation in the longitudinal direction of the steel strip 60, for example, quality failure such as magnetic failure and film defect, has been caused.

本願発明の発明者らは、この鋼帯６０の長手方向の昇温過程での板温を詳細に調査解析し、１本の鋼板コイル内の鋼帯６０長手方向の中央部でも昇温速度が少なからず変動することを見出した。この変動の原因をさらに解析した。鋼帯６０の連続加熱設備に用いられているラジアントチューブ炉においては、ラジアントチューブと鋼帯６０の間の輻射伝熱により鋼板が加熱されている。   The inventors of the present invention investigate and analyze the plate temperature in the temperature rising process in the longitudinal direction of the steel strip 60 in detail, and the temperature rising rate is also at the central portion in the longitudinal direction of the steel strip 60 in one steel plate coil. I found that it fluctuated. The cause of this variation was further analyzed. In the radiant tube furnace used in the continuous heating facility for the steel strip 60, the steel plate is heated by radiant heat transfer between the radiant tube and the steel strip 60.

鋼板の昇温量を決める伝熱量はラジアントチューブ、鋼板の放射率と幾何学的位置関係によって決まるが、ラジアントチューブの放射率及び幾何学的位置関係は短期的には不変であることから、鋼帯６０の温度は、鋼帯６０の放射率の変動で変化することを解明した。鋼板の放射率が長手方向に変化する要因としては、不明な点も多いが、冷延鋼板の製造の前工程である熱間圧延が連続でなく、スラブ単位（鋼帯６０コイルに相当）に行われ、熱間圧延中の板温度の長手方向変動及び冷却過程の不均一により表面性状が変化すること等によると推察した。   The amount of heat transfer that determines the temperature rise of the steel sheet is determined by the emissivity and geometric position of the radiant tube and steel sheet, but the emissivity and geometric position of the radiant tube are unchanged in the short term. It has been clarified that the temperature of the strip 60 changes due to the change in the emissivity of the steel strip 60. There are many unclear points as factors causing the emissivity of the steel sheet to change in the longitudinal direction, but the hot rolling, which is the pre-process of manufacturing a cold-rolled steel sheet, is not continuous and is in slab units (corresponding to 60 coils of steel strip) It was assumed that the surface properties changed due to longitudinal fluctuations in the plate temperature during hot rolling and non-uniform cooling processes.

また、鋼板の温度測定には鋼板の放射率が利用されていることから、放射率が変われば、板温の測定値の精度が悪くなることになる。複数の波長を用いた板温計も精度は若干改善されるもののこの問題から逃れることはできない。   Moreover, since the emissivity of a steel plate is used for the temperature measurement of a steel plate, if the emissivity changes, the accuracy of the measured value of the plate temperature will deteriorate. A plate thermometer using a plurality of wavelengths cannot be avoided from this problem, although the accuracy is slightly improved.

本願発明の発明者らは、鋭意、研究を重ねた結果、ソレノイドコイル式高周波誘導加熱では、キュリー点近傍で、鋼帯６０の透磁率が急速に低下し、それに伴い、浸透深さも大きくなるとともに、鋼帯６０の加熱能力が急速に減少することに着目した。   The inventors of the present invention have intensively studied, and as a result, in the solenoid coil type high frequency induction heating, the permeability of the steel strip 60 rapidly decreases near the Curie point, and the penetration depth increases accordingly. Focused on the rapid decrease in the heating capacity of the steel strip 60.

このことから、キュリー点近傍を含む鋼帯６０の加熱領域では、一定のコイル電流を通電中のソレノイドコイル式高周波誘導加熱装置の実績出力電力値は、鋼帯６０のコイル部入口の温度で変動することを見出すとともに、ソレノイドコイル式高周波誘導熱装置の制御応答性は極めて速いことにも着目した。   From this, in the heating region of the steel strip 60 including the vicinity of the Curie point, the actual output power value of the solenoid coil type high frequency induction heating device that is energized with a constant coil current varies depending on the temperature of the coil portion inlet of the steel strip 60. We have also noticed that the control response of the solenoid coil type high frequency induction heat apparatus is extremely fast.

図６に、高周波誘導装置を用いた基本的な構成例を示す。
図６は、冷間圧延された方向性珪素鋼を焼鈍するための連続熱処理設備ライン（図１）の炉部１２の構成を模式的に示す図である。図２で説明した基本的な構成の熱処理ラインに比べ、本実施形態の炉部１２Ｂにおいては加熱帯３１の中央に２個のソレノイドコイル式高周波誘導加熱装置３５Ａ、３５Ｂが配設されている。また、上流のソレノイドコイル式高周波誘導加熱装置３５Ａの前部に板温計３６が配置され、下流のソレノイドコイル式高周波誘導加熱装置３５Ｂの後に板温計３７が設置されている。これにより、加熱帯３１は、前段の加熱領域３１Ａと後段の加熱領域３１Ｂとに区分されている。 FIG. 6 shows a basic configuration example using a high-frequency induction device.
FIG. 6 is a diagram schematically showing the configuration of the furnace section 12 of the continuous heat treatment equipment line (FIG. 1) for annealing cold-rolled directional silicon steel. Compared to the heat treatment line having the basic configuration described with reference to FIG. 2, two solenoid coil high frequency induction heating devices 35 </ b> A and 35 </ b> B are disposed in the center of the heating zone 31 in the furnace section 12 </ b> B of the present embodiment. Further, a plate thermometer 36 is disposed in front of the upstream solenoid coil type high frequency induction heating device 35A, and a plate thermometer 37 is disposed after the downstream solenoid coil type high frequency induction heating device 35B. Thereby, the heating zone 31 is divided into a heating area 31A at the front stage and a heating area 31B at the rear stage.

図４に、高周波誘導装置を用いた基本的な構成例の制御方案を示す。
上流のソレノイドコイル式高周波誘導加熱装置３５Ａの入側の板温計３６の温度ＴAを監視する。 FIG. 4 shows a control method of a basic configuration example using a high-frequency induction device.
Monitoring the temperature T A of the upstream solenoid coil type of the incoming side of the high-frequency induction heating device 35A sheet temperature gauge 36.

そして、ラジアントチューブ方式による前段の加熱領域３１Ａの状態監視を行うとともに、下流のソレノイドコイル式高周波誘導加熱装置３５Ｂの入側の鋼板の板温が目標値となるように加熱するのに必要な加熱熱量を演算する。   Then, while monitoring the state of the preceding heating region 31A by the radiant tube method, heating necessary for heating the steel plate on the inlet side of the downstream solenoid coil type high frequency induction heating device 35B to a target value. Calculate the amount of heat.

そして、上流のソレノイドコイル式高周波誘導加熱装置３５Ａに設定出力電力値ＷAを与え、実績出力電力値が設定電力値になるよう制御するとともに、下流のソレノイドコイル式高周波誘導加熱装置３５Ｂには、目標値の電流値ＩBになるようにコイルに通電する電流値を制御して鋼帯を通板する。尚、出側の板温計３７の温度ＴBを監視し、下流のソレノイドコイル式高周波誘導加熱装置３５Ｂの出側の板温が一定であることを確認し、鋼帯６０を通板する。 Then, given a set output power value W A upstream of the solenoid coil type high frequency induction heating device 35A, and controls so that actual output power value becomes the set power value, downstream of the solenoid coil type high frequency induction heating device 35B is controls the current value to be supplied to the coil so that the current value I B of the target value Tsuban steel band. Incidentally, it monitors the exit side of the sheet temperature meter 37 the temperature T B of, verify that the delivery side of the sheet temperature of the downstream solenoid coil type high frequency induction heating device 35B is constant and Tsuban the steel strip 60.

図５（ａ）〜（ｄ）に、このときの炉部１２における、加熱領域３１Ａ、３５Ｂの各領域出側の板温計３６、３７の位置で測定された鋼帯コイル１本分の長手方向の温度分布、及びソレノイドコイル式高周波誘導加熱装置３５Ａ、３５Ｂの実績出力電力値の一例を示す。   5 (a) to 5 (d), the length of one steel strip coil measured at the position of the plate thermometers 36, 37 on the exit side of each heating region 31A, 35B in the furnace section 12 at this time. An example of the temperature distribution of a direction and the actual output electric power value of solenoid coil type high frequency induction heating apparatus 35A, 35B is shown.

この方法では、ラジアントチューブ方式による前段の加熱領域３１Ａの出側（上流のソレノイドコイル式高周波誘導加熱装置３５Ａの入側）では、図５（ａ）に示すように、板温計３６の測定データのように鋼帯の温度むらが存在するにもかかわらず、下流のソレノイドコイル式高周波誘導加熱装置３５Ｂでの出側では、図５（ｂ）に示すように、板温計３７の測定データのように温度はほぼ均一なる。   In this method, as shown in FIG. 5 (a), the measurement data of the plate thermometer 36 on the exit side of the upstream heating area 31A by the radiant tube method (on the entrance side of the upstream solenoid coil type high frequency induction heating device 35A). As shown in FIG. 5 (b), the measurement data of the plate thermometer 37 is shown on the exit side of the downstream solenoid coil type high frequency induction heating device 35B, despite the presence of uneven temperature in the steel strip. Thus, the temperature becomes almost uniform.

しかしながら、図５（ｃ）及び（ｄ）に示すように、上流のソレノイドコイル式高周波誘導加熱装置３５Ａ及び下流のソレノイドコイル式高周波誘導加熱装置３５Ｂの実績出力電力値は大きく変動しており、より昇温速度の管理が必要な領域において、鋼帯の昇温度速度は大きく変動している。   However, as shown in FIGS. 5C and 5D, the actual output power values of the upstream solenoid coil type high frequency induction heating device 35A and the downstream solenoid coil type high frequency induction heating device 35B vary greatly. In the region where the temperature increase rate needs to be managed, the temperature increase rate of the steel strip varies greatly.

これは、上流のソレノイドコイル式高周波誘導加熱装置３５Ａの入側の板温計３６が板温５００〜６００℃領域では、鋼板の放射率の変動が大きく、例え、測定精度の比較的良い２波長計測方式の板温計を使用しても、測定精度があまりよくないことに起因すると推察される。   This is because, when the plate thermometer 36 on the inlet side of the upstream solenoid coil type high frequency induction heating device 35A has a plate temperature in the range of 500 to 600 ° C., the fluctuation of the emissivity of the steel plate is large. Even if a measurement-type thermometer is used, it is assumed that the measurement accuracy is not so good.

図７に、高周波誘導装置を用いた本発明の制御方案を示す。
鋼帯６０は、前段の加熱領域３１Ａで加熱され、板温が５００℃以上で、キュリー点Ｔｃ（℃）から５０℃を超えて低い所定の温度（Ｔｃ−５０℃未満の温度）に到達する。その後、上流のソレノイドコイル式高周波誘導加熱装置３５Ａ、及び下流のソレノイドコイル式高周波誘導加熱装置３５Ｂにおいて、Ｔｃ−３０℃ないしＴｃ−５℃の温度領域まで加熱される。次いで、ラジアントチューブ方式による加熱領域（後半）３１Ｂでおよそ８２５℃まで加熱され、電気ヒータ加熱による均熱帯３２で脱炭焼鈍される。 FIG. 7 shows a control method of the present invention using a high frequency induction device.
The steel strip 60 is heated in the preceding heating region 31A, has a plate temperature of 500 ° C. or higher, and reaches a predetermined temperature lower than 50 ° C. (temperature less than Tc−50 ° C.) from the Curie point Tc (° C.). . Thereafter, in the upstream solenoid coil type high frequency induction heating device 35A and the downstream solenoid coil type high frequency induction heating device 35B, heating is performed to a temperature range of Tc-30 ° C to Tc-5 ° C. Subsequently, it is heated to about 825 ° C. in the heating region (second half) 31B by the radiant tube method, and decarburized and annealed in the soaking zone 32 by the electric heater heating.

鋼帯６０の通板方向の上流のソレノイドコイル式高周波誘導加熱装置３５Ａの入側の鋼帯６０の板温は、５００℃未満では、上流のソレノイドコイル式高周波誘導加熱装置３５Ａによる所要昇温代が大きくなり、そのためのソレノイドコイル式高周波誘導加熱装置３５の設備能力を過大にしなければならない。したがって、現実的でないばかりでなく、熱処理炉雰囲気に水素を含有する場合には、水素爆発の危険を回避できる雰囲気温度７５０℃以上を確保できなくなるため、板温５００℃以上とする必要がある。一方、当該板温がＴｃ−５０℃以上では、ラジアント方式の加熱での加熱ばらつきを誘導加熱装置での到達板温で吸収できないから、Ｔｃ−５０℃未満とする必要がある。   If the plate temperature of the steel strip 60 on the upstream side of the solenoid coil type high frequency induction heating device 35A in the upstream direction of the steel strip 60 is less than 500 ° C., the required heating allowance by the upstream solenoid coil type high frequency induction heating device 35A is required. Therefore, the facility capacity of the solenoid coil type high frequency induction heating device 35 for that purpose must be excessive. Therefore, not only is it not practical, but when hydrogen is contained in the heat treatment furnace atmosphere, it is not possible to secure an atmosphere temperature of 750 ° C. or higher that can avoid the danger of hydrogen explosion, and thus it is necessary to set the plate temperature to 500 ° C. or higher. On the other hand, when the plate temperature is Tc-50 ° C. or higher, it is necessary to make the temperature less than Tc-50 ° C. because the heating variation in the radiant heating cannot be absorbed by the ultimate plate temperature in the induction heating device.

また、鋼帯６０の通板方向の下流のソレノイドコイル式高周波誘導加熱装置３５Ｂの出側の鋼帯６０の板温は、Ｔｃ−５℃超では、出側での鋼帯６０の透磁率が小さ過ぎる。そのために、高周波誘導加熱装置に必要な磁界が大きくなって所要設備が巨大となり現実的でない。また、Ｔｃ−３０℃未満では、出側での鋼帯６０の透磁率が小さくなく、ラジアント方式の加熱での加熱ばらつきを高周波誘導加熱で抑制できない。したがって、下流のソレノイドコイル式高周波誘導加熱装置３５Ｂの出側の鋼帯６０の板温は、Ｔｃ−３０℃ないしＴｃ−５℃の温度領域とする必要がある。   Further, when the sheet temperature of the steel strip 60 on the outlet side of the solenoid coil type high frequency induction heating device 35B downstream in the plate passing direction of the steel strip 60 exceeds Tc-5 ° C., the permeability of the steel strip 60 on the outlet side is high. Too small. For this reason, the magnetic field required for the high frequency induction heating apparatus becomes large and the required equipment becomes huge, which is not realistic. Moreover, if it is less than Tc-30 degreeC, the magnetic permeability of the steel strip 60 on an exit side is not small, and the heating dispersion | variation by the heating of a radiant system cannot be suppressed by high frequency induction heating. Therefore, the sheet temperature of the steel strip 60 on the outlet side of the downstream solenoid coil type high frequency induction heating device 35B needs to be in the temperature range of Tc-30 ° C to Tc-5 ° C.

また、厳格な昇温速度管理を必要とする鋼帯６０の温度領域が、鋼帯６０の通板方向の下流にあるソレノイドコイル式高周波誘導加熱装置３５Ｂの制御領域になるように制御することが重要である。   Moreover, it is possible to control the temperature region of the steel strip 60 that requires strict temperature rise rate management to be the control region of the solenoid coil type high frequency induction heating device 35B that is downstream in the sheet passing direction of the steel strip 60. is important.

前述のように、ソレノイドコイル式高周波誘導加熱装置に一定値(目標値)の電流を通電し、鋼帯６０の昇温速度を一定にすること、及びソレノイドコイル式高周波誘導加熱装置の入側の鋼帯６０の温度が一定になるように制御するためには、少なくとも１個以上の別(上流)のソレノイドコイル式高周波誘導加熱装置を設けるのが好ましい。   As described above, the solenoid coil type high frequency induction heating device is energized with a constant value (target value) to make the heating rate of the steel strip 60 constant, and the solenoid coil type high frequency induction heating device is connected to the inlet side of the solenoid coil type high frequency induction heating device. In order to control the temperature of the steel strip 60 to be constant, it is preferable to provide at least one other (upstream) solenoid coil type high frequency induction heating device.

図７に、本実施形態による高周波誘導装置の制御方案を示す。
本実施形態の制御方式では、下流のソレノイドコイル式高周波誘導加熱装置３５Ｂには、目標値の電流値になるようにコイルに通電する電流ＩBを設定して鋼帯６０を通板し、下流のソレノイドコイル式高周波誘導加熱装置３５Ｂの実績出力電力値を検出する。 FIG. 7 shows a control method for the high-frequency induction device according to the present embodiment.
In the control system of the present embodiment, the downstream solenoid coil type high frequency induction heating device 35B, by setting the current I B to be supplied to the coil so that the current value of the target value Tsuban the steel strip 60, downstream The actual output power value of the solenoid coil type high frequency induction heating device 35B is detected.

そして、前記実績出力電力値と目標出力電力値との差ΔＷBを演算し、実績出力電力値が一定値になるように、下流のソレノイドコイル式高周波誘導加熱装置３５Ｂの上流のソレノイドコイル式高周波誘導加熱装置３５Ａの設定出力電力値ＷAOを補正し、上流のソレノイドコイル式高周波誘導加熱装置３５Ａの加熱動作を、下流のソレノイドコイル式高周波誘導加熱装置３５Ｂの実績出力電力値ＷBで制御する。尚、入側の板温計３６により板温ＴAを監視し、ラジアントチューブ方式による前段の加熱領域３１Ａの状態監視を行うとともに、出側の板温計３７を監視し、下流のソレノイドコイル式高周波誘導加熱装置３５Ｂの出側の板温ＴBが一定であることを確認し、鋼帯６０を通板する。 Then, it calculates a difference [Delta] W B between the actual output power value and the target output power value, so that actual output power value becomes a constant value, upstream of the solenoid coil type high frequency downstream solenoid coil type high frequency induction heating device 35B corrects the set output power value W AO of the induction heating device 35A, the heating operation of the upstream solenoid coil type high frequency induction heating device 35A, controlled by actual output power value W B of the downstream solenoid coil type high frequency induction heating device 35B . Incidentally, the sheet temperature T A was monitored by sheet temperature gauge 36 of the entry side, performs state monitoring of the preceding heating region 31A by radiant tube system, monitors the exit side of the sheet temperature meter 37, downstream of the solenoid coil type delivery side of the sheet temperature T B of the high-frequency induction heating device 35B is confirmed to be constant, Tsuban the steel strip 60.

図８（ａ）〜（ｄ）に、そのときの炉部１２における、前段の加熱領域３１Ａ、下流のソレノイドコイル式高周波誘導加熱装置３５Ｂの各領域出側の板温計３６、３７の位置で測定された鋼帯６０コイル１本分の長手方向の温度分布、及び下流のソレノイドコイル式高周波誘導加熱装置３５Ｂ、上流のソレノイドコイル式高周波誘導加熱装置３５Ａの実績出力電力値の一例を示す。   8 (a) to 8 (d), at the position of the plate thermometers 36 and 37 on the exit side of each region of the upstream heating region 31A and the downstream solenoid coil type high frequency induction heating device 35B in the furnace section 12 at that time. An example of the measured temperature distribution in the longitudinal direction of one steel strip 60 coil and the actual output power value of the downstream solenoid coil type high frequency induction heating device 35B and the upstream solenoid coil type high frequency induction heating device 35A is shown.

この時のソレノイドコイル式高周波誘導加熱装置３５Ａ、３５Ｂの境界での鋼帯６０の目標板温は６８０℃であった。尚、下流のソレノイドコイル式高周波誘導加熱装置３５Ｂの出側の鋼帯６０の板温は、Ｔｃ−３０℃未満では、下流のソレノイドコイル式高周波誘導加熱装置３５Ｂでの実績出力電力値の変動からその内部の鋼帯６０の温度バラツキを推定し、図８（ｃ）に示すように、ソレノイドコイル式高周波誘導加熱装置３５Ａの出力電力値を一定にする制御を有効に行うことができない。   At this time, the target plate temperature of the steel strip 60 at the boundary between the solenoid coil type high frequency induction heating devices 35A and 35B was 680 ° C. In addition, if the plate | board temperature of the steel strip 60 of the outgoing side of downstream solenoid coil type | mold high frequency induction heating apparatus 35B is less than Tc-30 degreeC, from the fluctuation | variation of the actual output electric power value in downstream solenoid coil type high frequency induction heating apparatus 35B. The temperature variation of the steel strip 60 inside is estimated, and as shown in FIG. 8 (c), the control to make the output power value of the solenoid coil type high frequency induction heating device 35A constant cannot be performed effectively.

本実施形態によれば、図８（ａ）に示すように、ラジアントチューブ方式による加熱領域３１Ａの出側では、板温計３６の測定データのように鋼帯６０の温度むらが存在するにもかかわらず、図８（ｂ）に示すように、下流のソレノイドコイル式高周波誘導加熱装置３５Ｂでの出側では、温度をほぼ均一にすることができる。 According to the present embodiment, as shown in FIG. 8A, on the exit side of the heating region 31A by the radiant tube method, the temperature unevenness of the steel strip 60 exists as in the measurement data of the plate thermometer 36. Regardless, as shown in FIG. 8B, the temperature can be made substantially uniform on the outlet side of the downstream solenoid coil type high frequency induction heating device 35B.

さらに、図８（ｄ）に示すように、下流のソレノイドコイル式高周波誘導加熱装置３５Ｂの実績出力電力値は殆ど変動することがなく非常に安定している。したがって、下流のソレノイドコイル式高周波誘導加熱装置３５Ｂにおける鋼帯６０の昇温速度は、一定で殆ど変動なく非常に安定させることができる。   Further, as shown in FIG. 8 (d), the actual output power value of the downstream solenoid coil type high frequency induction heating device 35B hardly fluctuates and is very stable. Therefore, the temperature increase rate of the steel strip 60 in the downstream solenoid coil type high frequency induction heating device 35B can be kept very constant with little fluctuation.

本実施形態による鋼帯６０の連続焼鈍設備により、方向性珪素鋼板の鋼帯６０を長手方向に、昇温速度を含めて、極めて均一に焼鈍処理できるようになったことから、得られた方向性珪素鋼板の品質も、再結晶組織や脱炭が均一となり、磁性が極めて高位に安定し、皮膜欠陥もほとんど解消した。   Since the steel strip 60 of the steel strip 60 according to the present embodiment can be annealed extremely uniformly, including the rate of temperature rise, in the longitudinal direction, the steel strip 60 of the directional silicon steel sheet can be obtained in the direction obtained. As for the quality of the heat-resistant silicon steel sheet, the recrystallized structure and decarburization became uniform, the magnetism was extremely stable, and the film defects were almost eliminated.

また、誘導加熱装置は２個に限定されるものでなく、複数であればよい。さらに、極めて厳格な鋼帯６０の昇温速度を要求される温度領域に応じて、出力電力値が一定となるようにされた誘導加熱装置が配置される。   Further, the number of induction heating devices is not limited to two, and may be plural. Furthermore, an induction heating device is provided in which the output power value is made constant in accordance with a temperature range in which a very strict heating rate of the steel strip 60 is required.

なお、図６では、窒化領域３３を有する例を示したが、本実施形態は、窒化領域を有する冷間圧延された方向性電磁鋼板の脱炭焼鈍設備に限定されるものではなく、窒化領域を有しない脱炭焼鈍設備にも有効である。   In addition, although the example which has the nitriding area | region 33 was shown in FIG. 6, this embodiment is not limited to the decarburization annealing equipment of the cold-rolled grain-oriented electrical steel sheet which has a nitriding area | region, A nitriding area | region It is also effective for decarburization annealing equipment that does not have any.

なお、本発明が処理対象とするキュリー点を有する鋼帯としては、ここで例示した方向性電磁鋼板の冷間圧延鋼帯に限定されることなく、無方向性電磁鋼板やフェライト系ステンレス鋼板の冷間圧延鋼帯等、キュリー点を有する鋼帯について全て有効である。   The steel strip having a Curie point to be treated by the present invention is not limited to the cold-rolled steel strip of the directional electromagnetic steel plate exemplified here, but of the non-oriented electrical steel plate or the ferritic stainless steel plate. All steel strips having a Curie point such as cold rolled steel strip are effective.

また、本発明が処理対象とするＳｉ≦４．５質量％を含有する方向性電磁鋼板としては、例えば、特開２００２−０６０８４２号公報や特開２００２−１７３７１５号公報等で開示されている方向性電磁鋼板のような成分系のものであればよく、本発明でその成分系を特に限定するものではない。   Moreover, as the grain-oriented electrical steel sheet containing Si ≦ 4.5 mass% to be processed by the present invention, for example, the directions disclosed in JP 2002-060842 A, JP 2002-173715 A, and the like. Any component system such as a heat-resistant electrical steel sheet may be used, and the component system is not particularly limited in the present invention.

なお、鋼帯６０をＴｃ−５０℃未満に加熱する装置としては、ラジアントチューブ方式の装置に限定されることなく、全ての間接ガス加熱もしくは直接ガス加熱による輻射加熱装置及び／または電気ヒータによる輻射加熱装置、及び／または誘導加熱方式による加熱装置において有効である。   The apparatus for heating the steel strip 60 to less than Tc-50 ° C. is not limited to a radiant tube type apparatus, but all indirect gas heating or radiation by a direct gas heating and / or radiation by an electric heater. It is effective in a heating device and / or a heating device using an induction heating method.

また、キュリー点近傍のＴｃ−３０℃ないしＴｃ−５℃の温度領域から処理目標温度まで加熱する方式も、電気ヒータ加熱方式に限定されることなく、全ての間接ガス加熱もしくは直接ガス加熱による輻射加熱装置及び／または電気ヒータによる輻射加熱装置で有効である。   Further, the method of heating from the temperature range of Tc-30 ° C. to Tc-5 ° C. near the Curie point to the processing target temperature is not limited to the electric heater heating method, and radiation by all indirect gas heating or direct gas heating is used. It is effective in a radiant heating device using a heating device and / or an electric heater.

また、一般的に、Ｔｃ−３０℃は、７００℃を超えており、この領域では鋼板の放射率は、絶対値が大きくなるとともに、比較的板表面の状況に左右されにくくなることから、鋼板の温度は制御しやすくなるので、Ｔｃ−３０℃以上では加熱方式をあまり問わない。   In general, Tc-30 ° C exceeds 700 ° C, and in this region, the emissivity of the steel plate increases in absolute value and is relatively less affected by the state of the plate surface. Since it becomes easy to control the temperature, the heating method is not particularly limited at Tc-30 ° C. or higher.

次に、本願発明の実施例を説明する。
質量％で、Ｃ：０．０５％、Ｓｉ：３．２％、Ｍｎ：０．１％、Ｐ：０．０３％、Ｓ：０．００６％、酸可溶性Ａｌ：０．０２７％、Ｎ：０．００８％、Ｃｒ：０．１％を含有する鋼スラブを１１５０℃の温度で加熱した後、板厚２．８ｍｍに熱間圧延して鋼帯６０（コイル）とし、その後、焼鈍温度１１２０℃及び９２０℃の二段焼鈍を施した。 Next, examples of the present invention will be described.
In mass%, C: 0.05%, Si: 3.2%, Mn: 0.1%, P: 0.03%, S: 0.006%, acid-soluble Al: 0.027%, N: A steel slab containing 0.008% and Cr: 0.1% is heated at a temperature of 1150 ° C. and then hot-rolled to a thickness of 2.8 mm to form a steel strip 60 (coil). C. and 920.degree. C. two-stage annealing was performed.

さらに、板厚０．２８５ｍｍまでリバース圧延機で冷間圧延した後、従来技術の脱炭焼鈍設備（図１、図２）、及び本実施形態の脱炭焼鈍設備（図１、図６）にて脱炭焼鈍した。また、本実施形態の脱炭焼鈍設備では、本実施形態の誘導加熱装置制御方案（図７で説明したα案）、及び基本的な制御方案（図４で説明したβ案）の両方で運転した。   Further, after cold rolling with a reverse rolling mill to a sheet thickness of 0.285 mm, the conventional decarburization annealing equipment (FIGS. 1 and 2) and the decarburization annealing equipment of this embodiment (FIGS. 1 and 6) are used. And decarburized and annealed. Moreover, in the decarburization annealing equipment of this embodiment, it operates by both the induction heating apparatus control plan (alpha plan demonstrated in FIG. 7) and the basic control plan (beta plan demonstrated in FIG. 4) of this embodiment. did.

この後、高温焼鈍を行ったあと、最後に平滑化焼鈍を行った。その際、脱炭焼鈍設備での加熱途中の鋼板温度を板温計３７で板温を測定した。また、高周波誘導加熱装置３５Ｂの実績電力出力値のバラツキを測定するとともに、平滑化焼鈍後の方向性電磁鋼板の磁性ならびに皮膜欠陥率を測定した。   Then, after performing high temperature annealing, finally smoothing annealing was performed. At that time, the plate temperature was measured with a plate thermometer 37 in the middle of heating in the decarburization annealing facility. Moreover, while measuring the dispersion | variation in the performance electric power output value of the high frequency induction heating apparatus 35B, the magnetism and film defect rate of the grain-oriented electrical steel sheet after smoothing annealing were measured.

図９に、試験条件と試験結果を示す。なお、誘導加熱の開始温度をＴｃ−Ａ（℃）、終了温度をＴｃ−Ｂ（℃）、高周波誘導加熱装置３５Ａ、３５Ｂの境界での鋼帯６０の目標板温をＴｃ−Ｂ−２０（℃）とし、図９では、ＡとＢの値で示した。また、コイル長手方向の品質の安定性の評価項目としては、連続測定が可能なものとして、磁性（鉄損値）と皮膜欠陥率（欠陥部の面積比率）を測定した（注：脱炭性は連続測定が困難）。   FIG. 9 shows test conditions and test results. The starting temperature of induction heating is Tc-A (° C.), the end temperature is Tc-B (° C.), and the target plate temperature of the steel strip 60 at the boundary between the high frequency induction heating devices 35A and 35B is Tc-B-20 ( In FIG. 9, the values are A and B. In addition, as an evaluation item of the stability of the quality in the longitudinal direction of the coil, magnetism (iron loss value) and film defect rate (defect area ratio) were measured as being capable of continuous measurement (Note: Decarburization) Is difficult to measure continuously).

本実施形態の例１、例２では、下流の誘導加熱装置出側の鋼帯６０の板温のバラツキは殆どない。且つ、下流の高周波誘導加熱装置の出力電力値のバラツキも殆どなく、高周波誘導加熱装置内の鋼板の昇温速度のバラツキがほとんどないことがわかる。また、結果として鋼板の磁気特性の絶対値が良好であるとともに、バラツキも小さく、皮膜欠陥率も非常に小さいことが分かる。   In Example 1 and Example 2 of this embodiment, there is almost no variation in the plate temperature of the steel strip 60 on the downstream side of the induction heating device. In addition, it can be seen that there is almost no variation in the output power value of the downstream high-frequency induction heating device, and there is almost no variation in the heating rate of the steel plates in the high-frequency induction heating device. As a result, it can be seen that the absolute value of the magnetic properties of the steel sheet is good, the variation is small, and the film defect rate is very small.

一方、誘導加熱終了温度の高すぎる比較例１１では、鋼板は目標温度に達せず、試験条件を満たすことができなかった。   On the other hand, in Comparative Example 11 where the induction heating end temperature was too high, the steel sheet did not reach the target temperature, and the test conditions could not be satisfied.

また、誘導加熱開始温度の高い比較例１３、１４では、依然として、下流の誘導加熱装置出側の鋼帯６０の板温のバラツキは比較的小さいが、下流の高周波誘導加熱装置の出力電力値のバラツキは小さくなく、高周波誘導加熱装置内の鋼板の昇温速度のバラツキも小さくないことがわかる。結果として鋼板の磁気特性の絶対値が低位であるとともに、バラツキも大きく、皮膜欠陥率も高かった。 Further, the induction heating start temperatures high Comparative Examples 13 and 14, still although sheet temperature variation of the steel strip 60 downstream of the induction heating device exit side is relatively small, the output power value of the downstream high frequency induction heating device It can be seen that the variation in the temperature is not small, and the variation in the heating rate of the steel plates in the high frequency induction heating apparatus is not small. As a result, the absolute value of the magnetic properties of the steel sheet was low, the variation was large, and the film defect rate was high.

また、制御方案の比較例２１、２２の場合の何れも、下流の誘導加熱装置出側の鋼帯６０の板温のバラツキは小さくなく、且つ、下流の高周波誘導加熱装置の出力電力値のバラツキは大きく、高周波誘導加熱装置内の鋼板の昇温速度のバラツキが大きいことが分かる。結果として鋼板の磁気特性の絶対値がやや低位であるとともに、バラツキも大きく、皮膜欠陥率も高かった。   Further, in any of Comparative Examples 21 and 22 of the control method, the variation in the plate temperature of the steel strip 60 on the downstream side of the induction heating device is not small, and the variation in the output power value of the downstream high-frequency induction heating device is small. It can be seen that there is a large variation in the heating rate of the steel plates in the high-frequency induction heating apparatus. As a result, the absolute value of the magnetic properties of the steel sheet was slightly low, the variation was large, and the film defect rate was high.

なお、誘導加熱を使用していない比較例３１は、加熱帯途中の鋼帯６０の板温のバラツキは非常に大きく、鋼板の昇温速度のバラツキは非常に大きいことがわかる。当然の結果として、鋼板の磁気特性の絶対値が更に低位であるとともに、バラツキも大きく、鋼板の皮膜欠陥率は非常に大きかった。   In addition, it can be seen that in Comparative Example 31 in which induction heating is not used, the variation in the plate temperature of the steel strip 60 in the middle of the heating zone is very large, and the variation in the rate of temperature rise of the steel plate is very large. As a natural result, the absolute value of the magnetic properties of the steel sheet was even lower, the variation was large, and the film defect rate of the steel sheet was very large.

次に、図１０を参照しながら、炉部１２の動作を制御する昇温速度制御装置１００の構成例を説明する。
図１０に示すように、本実施形態の昇温速度制御装置１００は、電力出力部１０１、電流出力部１０２、電力検出部１０３、演算部１０４、補正部１０５、第１の制御部１０６ａ、第２の制御部１０６ｂ、出力電力値設定部１０７、出力電流値設定部１０８等を有している。 Next, a configuration example of the temperature increase rate control apparatus 100 that controls the operation of the furnace unit 12 will be described with reference to FIG.
As illustrated in FIG. 10, the temperature increase rate control apparatus 100 according to the present embodiment includes a power output unit 101, a current output unit 102, a power detection unit 103, a calculation unit 104, a correction unit 105, a first control unit 106 a, 2 control unit 106b, output power value setting unit 107, output current value setting unit 108, and the like.

昇温速度制御装置１００は、前段の加熱領域３１Ａ、第２加熱帯３５、後段の加熱領域３１Ｂに区分されている炉部１２の加熱動作を制御するものであり、第２加熱帯３５の第１加熱部に設けられている上流のソレノイドコイル式高周波誘導加熱装置３５Ａ、及び第２加熱部に設けられている下流のソレノイドコイル式高周波誘導加熱装置３５Ｂの加熱動作を制御するための装置である。   The temperature increase rate control device 100 controls the heating operation of the furnace section 12 divided into the heating area 31A in the front stage, the second heating zone 35, and the heating area 31B in the subsequent stage. This is a device for controlling the heating operation of the upstream solenoid coil type high frequency induction heating device 35A provided in the one heating unit and the downstream solenoid coil type high frequency induction heating device 35B provided in the second heating unit. .

次に、前述のように構成された昇温速度制御装置１００の動作を、図１１のフローチャートを参照しながら説明する。
まず、ステップＳ１１０１において、第１加熱帯（前段の加熱領域３１Ａ）で鋼帯６０を５００℃以上、キュリー点Ｔｃ（℃）−５０℃未満の温度領域まで加熱する、第１加熱工程を行う。次に、ステップＳ１１０２において、鋼帯６０を目標温度まで加熱したか否かを判断する。この判断の結果、目標温度まで加熱していない場合にはステップＳ１１０１に戻って第１加熱工程における加熱を続行する。また、ステップＳ１１０２の判断の結果、目標温度まで加熱した場合にはステップＳ１１０３に進む。 Next, the operation of the temperature increase rate control apparatus 100 configured as described above will be described with reference to the flowchart of FIG.
First, in step S1101, a first heating step is performed in which the steel strip 60 is heated to a temperature range of 500 ° C. or higher and less than the Curie point Tc (° C.) − 50 ° C. in the first heating zone (previous heating region 31A). Next, in step S1102, it is determined whether or not the steel strip 60 has been heated to the target temperature. If the result of this determination is that the target temperature has not been reached, the process returns to step S1101 to continue heating in the first heating step. If the result of determination in step S1102 is that the target temperature has been reached, processing proceeds to step S1103.

ステップＳ１１０３においては、第１加熱工程で加熱された鋼帯６０をキュリー点Ｔｃ−３０℃ないしキュリー点Ｔｃ−５℃の温度領域まで、複数の制御領域で構成されたソレノイドコイル式高周波誘導により加熱する第２加熱工程を行う。その後、ステップＳ１１０４に進み、鋼帯６０を目標温度まで加熱したか否かを判断する。この判断の結果、目標温度まで加熱していない場合にはステップＳ１１０３に戻って第２加熱工程における加熱を続行する。また、ステップＳ１１０４の判断の結果、目標温度まで加熱した場合にはステップＳ１１０５に進む。   In step S1103, the steel strip 60 heated in the first heating step is heated to a temperature range from the Curie point Tc-30 ° C. to the Curie point Tc-5 ° C. by a solenoid coil type high-frequency induction composed of a plurality of control regions. A second heating step is performed. Then, it progresses to step S1104 and it is judged whether the steel strip 60 was heated to target temperature. If the result of this determination is that the target temperature has not been reached, the process returns to step S1103 to continue heating in the second heating step. If the result of determination in step S1104 is that the target temperature has been reached, processing proceeds to step S1105.

ステップＳ１１０５においては、第２加熱工程で加熱された鋼帯６０を、第３加熱帯（後段の加熱領域３１Ｂ）において前記キュリー点Ｔｃを超える処理目標温度領域まで加熱する第３加熱工程を行う。次に、ステップＳ１１０６において、鋼帯６０を目標温度まで加熱したか否かを判断する。この判断の結果、目標温度まで加熱していない場合にはステップＳ１１０５に戻って第３加熱工程における加熱を続行する。また、ステップＳ１１０６の判断の結果、目標温度まで加熱した場合には処理を終了する。   In step S1105, a third heating step is performed in which the steel strip 60 heated in the second heating step is heated to a processing target temperature region that exceeds the Curie point Tc in the third heating zone (the subsequent heating region 31B). Next, in step S1106, it is determined whether or not the steel strip 60 has been heated to the target temperature. If the result of this determination is that the target temperature has not been reached, processing returns to step S1105 and heating in the third heating step is continued. If the result of determination in step S1106 is that the target temperature has been reached, processing is terminated.

次に、図１２のフローチャートを参照しながら、ステップＳ１１０３で行う第２加熱工程の詳細を説明する。
まず、ステップＳ１２０１において、下流のソレノイドコイル式高周波誘導加熱装置３５Ｂに出力する電流値を目標出力電流値として設定する出力電流値設定処理を出力電流値設定部１０８で行う。そして、出力電流値設定部１０８で設定された目標出力電流値が下流のソレノイドコイル式高周波誘導加熱装置３５Ｂに供給されるように、第２の制御部１０６ｂで制御する。 Next, the details of the second heating step performed in step S1103 will be described with reference to the flowchart of FIG.
First, in step S1201, the output current value setting unit 108 performs an output current value setting process for setting a current value output to the downstream solenoid coil type high frequency induction heating device 35B as a target output current value. And it controls by the 2nd control part 106b so that the target output current value set by the output current value setting part 108 may be supplied to the downstream solenoid coil type high frequency induction heating apparatus 35B.

次に、ステップＳ１２０２において、前述した下流のソレノイドコイル式高周波誘導加熱装置３５Ｂの実績出力電力値を、電力検出部１０３により検出する検出処理を行う。
次に、ステップＳ１２０３において、前述した検出処理により検出した実績出力電力値を基に、前述した目標出力電力値と実績出力電力値の差を演算部１０４で演算する演算処理を行う。 Next, in step S1202, a detection process is performed in which the power detection unit 103 detects the actual output power value of the downstream solenoid coil type high frequency induction heating device 35B described above.
Next, in step S1203, based on the actual output power value detected by the above-described detection process, a calculation process is performed in which the calculation unit 104 calculates the difference between the target output power value and the actual output power value.

次に、ステップＳ１２０４において、前述した演算処理により求めた出力電力値の差を基にして、出力電力値設定部１０７に設定されている目標出力電力値を補正する補正処理を行う。出力電力値設定部１０７に設定されている目標出力電力値の補正処理は補正部１０５により行う。   Next, in step S1204, correction processing for correcting the target output power value set in the output power value setting unit 107 is performed based on the difference between the output power values obtained by the arithmetic processing described above. Correction processing of the target output power value set in the output power value setting unit 107 is performed by the correction unit 105.

次に、ステップＳ１２０５において、電力出力部１０１から上流のソレノイドコイル式高周波誘導加熱装置３５Ａに出力する電力を、出力電力値設定部１０７に設定された目標出力電力値とする制御を第１の制御部１０６ａで行う。また、電流出力部１０２から下流のソレノイドコイル式高周波誘導加熱装置３５Ｂに出力する電流値を、出力電流値設定部１０８に設定された目標出力電流値とする制御を第２の制御部１０６ｂで行う。前述したステップＳ１２０１〜ステップＳ１２０５の処理を実行することにより、第２加熱工程における昇温速度制御が実行される。   Next, in step S1205, the first control is performed so that the power output from the power output unit 101 to the upstream solenoid coil type high frequency induction heating device 35A is the target output power value set in the output power value setting unit 107. This is performed by the unit 106a. Further, the second control unit 106b performs control so that the current value output from the current output unit 102 to the downstream solenoid coil type high frequency induction heating device 35B is the target output current value set in the output current value setting unit 108. . By executing the processes of steps S1201 to S1205 described above, the temperature increase rate control in the second heating step is executed.

方向性珪素鋼の冷延板を脱炭焼鈍（焼鈍分離剤の塗布を含む）するための代表的な連続熱処理設備の一例を示すブロック図である。It is a block diagram which shows an example of the typical continuous heat processing equipment for carrying out the decarburization annealing (including application | coating of an annealing separator) of the cold-rolled sheet | seat of directionality silicon steel. 図１における炉部の基本的な構成例を模式的に示す図である。It is a figure which shows typically the example of a fundamental structure of the furnace part in FIG. 基本的な構成の炉部の加熱領域内の代表的な２箇所で測定された鋼帯の板温の長手方向推移の例を示す特性図である。It is a characteristic view which shows the example of the longitudinal direction transition of the plate | board temperature of the steel strip measured in two typical places in the heating area | region of the furnace part of a basic composition. 本発明の基本的な制御方案を模式的に示す図である。It is a figure which shows typically the basic control method of this invention. 本発明の基本的な制御方案による運転時に各領域出側で測定された鋼帯の板温、及び誘導加熱装置の実績出力電力値の長手方向推移の例を示す特性図である。It is a characteristic view which shows the example of the longitudinal direction transition of the sheet | seat temperature of the steel strip measured by each area | region exit side at the time of the driving | operation by the basic control method of this invention, and the actual output power value of an induction heating apparatus. 本発明の実施形態を示し、冷間圧延された方向性珪素鋼を焼鈍するための連続熱処理設備ラインの炉部の構成を模式的に示す図である。It is a figure which shows embodiment of this invention and shows the structure of the furnace part of the continuous heat processing equipment line for annealing the directional silicon steel which carried out cold rolling. 本実施形態による高周波誘導装置の制御方案を模式的に示す図である。It is a figure which shows typically the control method of the high frequency induction device by this embodiment. 本実施形態の制御方案による運転時に各領域出側で測定された鋼帯の板温、及び誘導加熱装置の実績出力電力値の長手方向推移の例を示す特性図である。It is a characteristic view which shows the example of the longitudinal direction transition of the sheet | seat temperature of the steel strip measured by each area | region exit side at the time of the driving | operation by the control method of this embodiment, and the actual output power value of an induction heating apparatus. 本発明の実施形態を示し、試験条件と試験結果を示す図である。It is a figure which shows embodiment of this invention and shows a test condition and a test result. 本発明の実施形態を示し、炉部の動作を制御する制御装置の構成例を説明する図である。It is a figure which shows embodiment of this invention and demonstrates the structural example of the control apparatus which controls operation | movement of a furnace part. 本発明の実施形態を示し、昇温速度制御装置の動作を説明するフローチャートである。It is a flowchart which shows embodiment of this invention and demonstrates operation | movement of a temperature increase rate control apparatus. 本発明の実施形態を示し、第２加熱工程の詳細を説明するフローチャートである。It is a flowchart which shows embodiment of this invention and demonstrates the detail of a 2nd heating process.

符号の説明Explanation of symbols

１ ペイオフリール
２ 入側剪断機
３ 溶接機
４ 入側ストレージルーパー
５ 出側ストレージルーパー
６ 出側剪断機
７ テンションリール
１１ 入側洗浄装置
１２ 炉部
１３ 出側洗浄装置
１４ 焼鈍分離剤塗布装置
１５ 焼鈍分離剤乾燥装置
２１〜２６ ブライドルロール
３１ ラジアントチューブ方式による加熱領域
３１Ａ ラジアントチューブ方式による加熱領域（前段）
３１Ｂ ラジアントチューブ方式による加熱領域（後段）
３２ 均熱領域
３３ 窒化領域
３４ 冷却領域
３５Ａ 上流のソレノイドコイル式高周波誘導加熱装置
３５Ｂ 下流のソレノイドコイル式高周波誘導加熱装置
３６、３７、３８ 板温計
４１、４２、４３ テンションメータ
６０ 鋼帯
１００ 昇温速度制御装置
１０１ 電力出力部
１０２ 電流出力部
１０３ 電力検出部
１０４ 演算部
１０５ 補正部
１０６ａ 第１の制御部
１０６ｂ 第２の制御部
１０７ 出力電力値設定部
１０８ 出力電流値設定部
ＴA 上流のソレノイドコイル式高周波誘導加熱装置入側の鋼帯の板温
ＴB 下流のソレノイドコイル式高周波誘導加熱装置出側の鋼帯の板温 DESCRIPTION OF SYMBOLS 1 Payoff reel 2 Entry side shear machine 3 Welding machine 4 Entry side storage looper 5 Entry side storage looper 6 Entry side shear machine 7 Tension reel 11 Entry side cleaning device 12 Furnace part 13 Entry side cleaning device 14 Annealing separator coating device 15 Annealing Separating agent drying devices 21 to 26 Bridle roll 31 Heating area 31A by radiant tube system Heating area by radiant tube system (previous stage)
31B Radiant tube heating area (second stage)
32 Soaking area 33 Nitriding area 34 Cooling area 35A Solenoid coil type high frequency induction heating device 35B upstream Solenoid coil type high frequency induction heating device 36, 37, 38 Plate thermometers 41, 42, 43 Tension meter 60 Steel strip 100 Ascending Temperature speed control device 101 Power output unit 102 Current output unit 103 Power detection unit 104 Operation unit 105 Correction unit 106a First control unit 106b Second control unit 107 Output power value setting unit 108 Output current value setting unit T A Upstream solenoid coil type high frequency induction heating device entry side of the plate of the steel strip temperature T B downstream of the solenoid coil type high frequency induction heating device outlet side of the plate of the steel strip temperature

Claims (8)

加熱帯、均熱帯及び冷却帯、または加熱帯、均熱帯、窒化帯及び冷却帯からなり、前記加熱帯が第１加熱帯、第２加熱帯及び第３加熱帯に区分されている連続焼鈍設備での、キュリー点を有する鋼帯の連続焼鈍方法であって、
前記第１加熱帯において、前記鋼帯を５００℃以上、キュリー点Ｔｃ（℃）−５０℃未満まで加熱する第１加熱工程と、
前記第２加熱帯において、前記第１加熱帯で加熱された鋼帯をキュリー点Ｔｃ−３０℃ないしキュリー点Ｔｃ−５℃の温度領域まで、上流のソレノイドコイル式高周波誘導加熱装置及び下流のソレノイドコイル式高周波誘導加熱装置により加熱する第２加熱工程と、
前記第３加熱帯において、前記第２加熱帯で加熱された鋼帯をキュリー点を超える処理目標温度まで加熱する第３加熱工程と、
前記第２加熱工程の加熱動作を制御する昇温速度制御工程とを有し、
前記昇温速度制御工程は、前記上流のソレノイドコイル式高周波誘導加熱装置に電力を出力する電力出力部と、前記下流のソレノイドコイル式高周波誘導加熱装置に電流を出力する電流出力部とを制御し、
前記下流のソレノイドコイル式高周波誘導加熱装置での実績出力電力値に基いて前記上流のソレノイドコイル式高周波誘導加熱装置の出力電力値を制御するようにしたことを特徴とするキュリー点を有する鋼帯の連続焼鈍方法。 Continuous annealing equipment comprising a heating zone, a soaking zone and a cooling zone, or a heating zone, a soaking zone, a nitriding zone and a cooling zone, wherein the heating zone is divided into a first heating zone, a second heating zone and a third heating zone A continuous annealing method of a steel strip having a Curie point,
In the first heating zone, a first heating step of heating the steel strip to 500 ° C. or higher and a Curie point Tc (° C.) to less than −50 ° C .;
In the second heating zone, an upstream solenoid coil type high-frequency induction heating device and a downstream solenoid are heated up to a temperature range of Curie point Tc-30 ° C to Curie point Tc-5 ° C. A second heating step of heating by a coil type high frequency induction heating device;
In the third heating zone, a third heating step of heating the steel strip heated in the second heating zone to a processing target temperature exceeding the Curie point;
A heating rate control step for controlling the heating operation of the second heating step,
The heating rate control step controls a power output unit that outputs power to the upstream solenoid coil type high frequency induction heating device and a current output unit that outputs current to the downstream solenoid coil type high frequency induction heating device. ,
A steel strip having a Curie point, wherein the output power value of the upstream solenoid coil type high frequency induction heating device is controlled based on the actual output power value of the downstream solenoid coil type high frequency induction heating device. Continuous annealing method. 前記昇温速度制御工程は、前記電流出力部から前記下流のソレノイドコイル式高周波誘導加熱装置に出力する目標出力電流値を出力電流値設定部に設定する出力電流値設定処理と、前記電力出力部から前記上流のソレノイドコイル式高周波誘導加熱装置に出力する目標出力電力値を出力電力値設定部に設定する出力電力値設定処理と、下流のソレノイドコイル式高周波誘導加熱装置での実績出力電力値を検出する電力検出処理と、前記出力電力値設定部に設定されている目標出力電力値を補正する出力電力値補正工程とを有し、
前記キュリー点近傍の鋼帯の昇温速度を一定にすることを特徴とする請求項１に記載のキュリー点を有する鋼帯の連続焼鈍方法。 The heating rate control step includes an output current value setting process for setting a target output current value to be output from the current output unit to the downstream solenoid coil type high frequency induction heating device in an output current value setting unit, and the power output unit. Output power value setting processing for setting the target output power value to be output to the upstream solenoid coil type high frequency induction heating device from the output power value setting unit, and the actual output power value in the downstream solenoid coil type high frequency induction heating device. A power detection process to detect, and an output power value correction step of correcting the target output power value set in the output power value setting unit,
The method for continuously annealing a steel strip having a Curie point according to claim 1, wherein a temperature rising rate of the steel strip near the Curie point is made constant. 前記第１加熱工程及び第３加熱工程においては、間接ガス加熱もしくは直接ガス加熱による輻射加熱及び／または電気ヒータによる輻射加熱により前記鋼帯を加熱することを特徴とする請求項１または２に記載のキュリー点を有する鋼帯の連続焼鈍方法。   The steel strip is heated by radiation heating by indirect gas heating or direct gas heating and / or radiation heating by an electric heater in the first heating step and the third heating step. A method for continuous annealing of steel strips having a Curie point. 前記キュリー点を有する鋼帯が、Ｓｉ≦４．５質量％を含有する冷間圧延された方向性電磁鋼板であることを特徴とする請求項１または２に記載のキュリー点を有する鋼帯の連続焼鈍方法。   The steel strip having a Curie point according to claim 1 or 2, wherein the steel strip having a Curie point is a cold-rolled grain-oriented electrical steel sheet containing Si ≤ 4.5 mass%. Continuous annealing method. 加熱帯、均熱帯及び冷却帯、または加熱帯、均熱帯、窒化帯及び冷却帯からなり、前記加熱帯が第１加熱帯、第２加熱帯及び第３加熱帯に区分されているキュリー点を有する鋼帯の連続焼鈍設備であって、
前記第１加熱帯において、前記鋼帯を５００℃以上、キュリー点Ｔｃ（℃）−５０℃未満まで加熱する第１加熱手段と、
前記第２加熱帯において、前記第１加熱帯で加熱された鋼帯をキュリー点Ｔｃ−３０℃ないしキュリー点Ｔｃ−５℃の温度領域まで、上流のソレノイドコイル式高周波誘導加熱装置及び下流のソレノイドコイル式高周波誘導加熱装置により加熱する第２加熱手段と、
前記第３加熱帯において、前記第２加熱帯で加熱された鋼帯をキュリー点を超える処理目標温度まで加熱する第３加熱手段と、
前記第２加熱手段の加熱動作を制御する昇温速度制御装置とを有し、
前記昇温速度制御装置は、前記上流のソレノイドコイル式高周波誘導加熱装置に電力を出力する電力出力部と、前記下流のソレノイドコイル式高周波誘導加熱装置に電流を出力する電流出力部とを有し、
前記下流のソレノイドコイル式高周波誘導加熱装置での実績出力電力値に基いて前記上流のソレノイドコイル式高周波誘導加熱装置の出力電力値を制御するようにしたことを特徴とするキュリー点を有する鋼帯の連続焼鈍設備。 A Curie point consisting of a heating zone, a soaking zone and a cooling zone, or a heating zone, a soaking zone, a nitriding zone and a cooling zone, wherein the heating zone is divided into a first heating zone, a second heating zone and a third heating zone. A continuous annealing facility for steel strips,
In the first heating zone, a first heating means for heating the steel strip to 500 ° C. or higher and a Curie point Tc (° C.) to less than −50 ° C .;
In the second heating zone, an upstream solenoid coil type high-frequency induction heating device and a downstream solenoid are heated up to a temperature range of Curie point Tc-30 ° C to Curie point Tc-5 ° C. A second heating means for heating by a coil type high frequency induction heating device;
In the third heating zone, a third heating means for heating the steel strip heated in the second heating zone to a processing target temperature exceeding the Curie point;
A heating rate control device for controlling the heating operation of the second heating means,
The temperature increase rate control device includes a power output unit that outputs power to the upstream solenoid coil type high frequency induction heating device, and a current output unit that outputs current to the downstream solenoid coil type high frequency induction heating device. ,
A steel strip having a Curie point, wherein the output power value of the upstream solenoid coil type high frequency induction heating device is controlled based on the actual output power value of the downstream solenoid coil type high frequency induction heating device. Continuous annealing equipment. 前記昇温速度制御装置は、前記電流出力部から前記下流のソレノイドコイル式高周波誘導加熱装置に出力する目標出力電流値を設定する出力電流値設定部と、前記電力出力部から前記上流のソレノイドコイル式高周波誘導加熱装置に出力する目標出力電力値を設定する出力電力値設定部と、下流のソレノイドコイル式高周波誘導加熱装置での実績出力電力値を検出する電力検出部と、前記出力電力値設定部に設定されている目標出力電力値を補正する出力電力値補正手段とを有し、
前記キュリー点近傍の鋼帯の昇温速度を一定にすることを特徴とする請求項５に記載のキュリー点を有する鋼帯の連続焼鈍設備。 The temperature increase rate control device includes: an output current value setting unit that sets a target output current value to be output from the current output unit to the downstream solenoid coil type high frequency induction heating device; and an upstream solenoid coil from the power output unit Output power value setting unit for setting the target output power value to be output to the high frequency induction heating device, the power detection unit for detecting the actual output power value in the downstream solenoid coil type high frequency induction heating device, and the output power value setting Output power value correction means for correcting the target output power value set in the unit,
6. The continuous annealing equipment for steel strips having a Curie point according to claim 5, wherein a temperature rising rate of the steel strip near the Curie point is made constant. 前記第１加熱手段及び第３加熱手段においては、間接ガス加熱もしくは直接ガス加熱による輻射加熱及び／または電気ヒータによる輻射加熱により前記鋼帯を加熱することを特徴とする請求項５または６に記載のキュリー点を有する鋼帯の連続焼鈍設備。   The said 1st heating means and 3rd heating means heat the said steel strip by the radiation heating by indirect gas heating or direct gas heating, and / or the radiation heating by an electric heater, It is characterized by the above-mentioned. Continuous annealing equipment for steel strips with a Curie point. 前記キュリー点を有する鋼帯が、Ｓｉ≦４．５質量％を含有する冷間圧延された方向性電磁鋼板であることを特徴とする請求項５または６に記載のキュリー点を有する鋼帯の連続焼鈍設備。   The steel strip having a Curie point according to claim 5 or 6, wherein the steel strip having a Curie point is a cold-rolled grain-oriented electrical steel sheet containing Si ≦ 4.5% by mass. Continuous annealing equipment.
JP2008070241A 2007-04-05 2008-03-18 Continuous annealing method and continuous annealing equipment for steel strip with Curie point Expired - Fee Related JP5217542B2 (en)

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CN2008800111153A CN101652485B (en) 2007-04-05 2008-04-04 Method of continuous annealing for steel strip with curie point and continuous annealing apparatus therefor
BRPI0811253-3A2A BRPI0811253A2 (en) 2007-04-05 2008-04-04 STEEL STRIP RECOGNITION METHOD WITH A CURIE POINT AND CONTINUOUS RECOGNITION FACILITY
PL08740220T PL2133436T3 (en) 2007-04-05 2008-04-04 Method of continuous annealing for steel strip with curie point and continuous annealing apparatus therefor
RU2009140785/02A RU2414513C1 (en) 2007-04-05 2008-04-04 Procedure for continuous annealing strip steel with curie peak and installation for continuous annealing such steel
US12/450,650 US20100101690A1 (en) 2007-04-05 2008-04-04 Method for continously annealing steel strip having a curie point and continous annealing facility of the same
EP08740220.2A EP2133436B1 (en) 2007-04-05 2008-04-04 Method of continuous annealing for steel strip with curie point and continuous annealing apparatus therefor
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