JPH07197135A - Temperature controller - Google Patents
Temperature controllerInfo
- Publication number
- JPH07197135A JPH07197135A JP6011351A JP1135194A JPH07197135A JP H07197135 A JPH07197135 A JP H07197135A JP 6011351 A JP6011351 A JP 6011351A JP 1135194 A JP1135194 A JP 1135194A JP H07197135 A JPH07197135 A JP H07197135A
- Authority
- JP
- Japan
- Prior art keywords
- heating
- temperature
- coil
- steel bar
- induction heating
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/25—Process efficiency
Landscapes
- Control Of Heat Treatment Processes (AREA)
Abstract
Description
【0001】[0001]
【産業上の利用分野】本発明は、棒鋼分析試料の圧延整
形を容易にするために前工程として誘導加熱するとき、
加熱温度を、キューリー温度を検出することにより予め
設定した上限値以下に精度良く制御しようとするもので
ある。BACKGROUND OF THE INVENTION The present invention relates to induction heating as a pre-process in order to facilitate the rolling and shaping of steel bar analysis samples,
The heating temperature is accurately controlled to be equal to or lower than a preset upper limit value by detecting the Curie temperature.
【0002】[0002]
【従来の技術】加熱方法には燃焼ガス方式と電力による
方式があり、抵抗加熱炉は電気炉のなかでも最も一般的
なものである。そして、加熱方式が燃焼ガスによると電
力によるとにかかわらず、加熱される物体の温度の測定
には、温度計が用いられる。この常識に従って、熱電対
や測温抵抗体などの接触式温度計と、非接触温度計であ
る放射温度計が従来から賞用されてきた。そして比較的
新しい加熱方式である高周波加熱炉においても、同様
に、温度計を別個に用意するのが通例とされてきたが、
高周波加熱炉に限って、熱電対や測温抵抗体などの電気
的接触式温度計は、その構成要素を成す電気的導体が高
周波加熱コイル内で強力な誘導電磁波の影響を受けるた
め、全く測温本来の目的を達し得ない。したがって、高
周波加熱炉には、放射温度計が採用される場合が多い。2. Description of the Related Art A heating method includes a combustion gas method and an electric power method, and a resistance heating furnace is the most general electric furnace. A thermometer is used to measure the temperature of the object to be heated, regardless of whether the heating method is combustion gas or electric power. In accordance with this common sense, contact thermometers such as thermocouples and resistance temperature detectors, and radiation thermometers that are non-contact thermometers have been used for a long time. In the case of a high frequency heating furnace, which is a relatively new heating method, it has been customary to prepare a thermometer separately as well.
Only in the high frequency heating furnace, the electrical contact type thermometer such as thermocouple and resistance thermometer is completely measured because the electric conductors forming its components are affected by strong induction electromagnetic waves in the high frequency heating coil. Wen cannot achieve his original purpose. Therefore, a radiation thermometer is often used in the high frequency heating furnace.
【0003】[0003]
【発明が解決しようとする課題】放射温度計には、被測
定物体の表面の光学的放射率が正確に知られていること
が、正確な測温の大前提となる。然るに、酸化膜が容易
に生成する棒鋼等の金属においては、光学的放射率が時
間と共に、また、温度と共に変化するため、予め想定し
た近似的な仮想放射率に頼って温度補正する場合がほと
んどであり、接触式温度計と同等な加熱上限温度管理精
度は到底得られない。In the radiation thermometer, it is a major premise of accurate temperature measurement that the optical emissivity of the surface of the object to be measured is accurately known. However, in metals such as steel bars where an oxide film is easily formed, the optical emissivity changes with time and with temperature, so in most cases temperature correction is performed by relying on an approximate virtual emissivity that is assumed in advance. Therefore, the heating upper limit temperature control accuracy equivalent to that of the contact type thermometer cannot be obtained at all.
【0004】[0004]
【課題を解決するための手段】本発明は従来技術につき
まとう上記の課題を有利に解決するものであって、強磁
性から常磁性に転換する所謂キューリー温度TCを検出
して高周波加熱物体の加熱状態を制御せんとするもので
ある。SUMMARY OF THE INVENTION The present invention advantageously solves the above problems associated with the prior art by detecting the so-called Curie temperature T C at which ferromagnetism is transformed into paramagnetism and detecting the high frequency heating object. It is intended to control the heating state.
【0005】[0005]
【実施例】以下、図面に基づいて本発明を説明する。図
1は本発明の実施例を示す図である。1は発振器で、商
用電源電力を入力とし、高周波電力を出力する。2はイ
ンピーダンス整合回路で、通常は常温において、誘導加
熱コイル3内に挿入された棒鋼4に印加される高周波エ
ネルギー出力を最大に設定するように、インピーダンス
を整合させる。4は棒鋼で、本発明の方法により高周波
誘導加熱温度が目的温度に制御される。5は出力電流計
で、誘導加熱コイル3に流れる高周波電流値を検出す
る。6は演算制御部で、出力電流計5が検出した高周波
電流の変化を演算し、かつ発振器1の発振動作を遮断も
しくは制御することにより棒鋼4の加熱上限温度を制御
する。DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an embodiment of the present invention. Reference numeral 1 is an oscillator, which receives commercial power source power and outputs high frequency power. Reference numeral 2 is an impedance matching circuit, which normally matches impedance so as to set the high frequency energy output applied to the steel bar 4 inserted in the induction heating coil 3 to the maximum at normal temperature. 4 is a steel bar, and the high frequency induction heating temperature is controlled to the target temperature by the method of the present invention. An output ammeter 5 detects a high frequency current value flowing in the induction heating coil 3. Reference numeral 6 denotes a calculation control unit which calculates the change in the high frequency current detected by the output ammeter 5 and cuts or controls the oscillation operation of the oscillator 1 to control the upper heating temperature of the steel bar 4.
【0006】図2は本発明の原理を説明する図である。
横座標軸の温度は、棒鋼4の温度である。縦座標軸は、
誘導加熱コイル3に流れ、出力電流計5が検出する高周
波電流値である。棒鋼4が常温において、強磁性(フェ
ロマグネティズム)であることを考慮して、予めインピ
ーダンス整合回路2の回路定数をコイル3に流れる電流
が最大となるように設定しておくならば、キューリー温
度TCにまで加熱された棒鋼4が常磁性(パラマグネテ
ィズム)に磁性転換したことによってコイル3のインピ
ーダンスが変化し、インピーダンス整合条件が破綻して
コイル3に流れる電流が低下する。FIG. 2 is a diagram for explaining the principle of the present invention.
The temperature on the abscissa axis is the temperature of the steel bar 4. The ordinate axis is
It is a high frequency current value that flows through the induction heating coil 3 and is detected by the output ammeter 5. Considering that the steel bar 4 is ferromagnetic (ferromagnetism) at room temperature, if the circuit constant of the impedance matching circuit 2 is set in advance so that the current flowing through the coil 3 becomes maximum, the Curie temperature is set. The steel bar 4 heated to T C changes its magnetism to paramagnetism, whereby the impedance of the coil 3 changes, the impedance matching condition is broken, and the current flowing through the coil 3 decreases.
【0007】[0007]
【本発明の特徴】本発明の特徴とするところは、出力電
流計5が検出する高周波電流の劇的な変化すなわち、棒
鋼4が常温における強磁性から常磁性に転換する所謂キ
ューリー温度TCの存在に由来することに着眼し、誘導
加熱エネルギー源であるコイル電流それ自体が変化した
ときを加熱温度基準点、即ちキューリー温度TCに達し
たときと判定し、表面状態や形状など外因的誤検出の危
険を包含するセンサを使用すること無しに確実に過剰加
熱を防止する方法を提供することにある。The feature of the present invention is that the high-frequency current detected by the output ammeter 5 changes dramatically, that is, the so-called Curie temperature T C at which the steel bar 4 is changed from ferromagnetic to paramagnetic at room temperature. Focusing on the origin, the time when the coil current, which is an induction heating energy source, changes is determined to have reached the heating temperature reference point, that is, the Curie temperature T C , and an external error such as a surface state or a shape is determined. It is to provide a method for reliably preventing overheating without the use of a sensor that involves the risk of detection.
【0008】ちなみに、純鉄のキューリー温度TCは7
68°Cであり、工業製品たる棒鋼は炭素をはじめ意図
的添加物元素たると不純物たるとを問わず、複数の他元
素が組成中に存在しても鉄鋼のキューリー温度TCは殆
ど変化しない。キューリー温度TCは一度組成が決定す
れば極めて安定し、外乱の少ない物理効果である。この
ことは、放射温度計による測温につきまとう高温におけ
る酸化膜の還元がもたらす放射率の急激な低下に対し、
これを補償して真の温度を推定するための放射率補正の
煩雑さを考えただけでも、本方法の優秀さを理解するに
十分な特徴のひとつといえる。Incidentally, the Curie temperature T C of pure iron is 7
The temperature is 68 ° C, and the Curie temperature T C of steel hardly changes even if a plurality of other elements are present in the composition, regardless of whether the steel bar, which is an industrial product, is an intentional additive element or an impurity such as carbon. The Curie temperature T C is a physical effect that is extremely stable once the composition is determined and has little disturbance. This means that the emissivity decreases sharply due to the reduction of the oxide film at high temperature, which is caused by the radiation thermometer.
Considering the complexity of the emissivity correction for compensating for this and estimating the true temperature is one of the features sufficient to understand the superiority of this method.
【0009】しかも、棒鋼中の含有成分、酸素、窒素、
硫黄、炭素等の元素濃度を分析するための棒鋼試料整形
を容易にするための高周波誘導加熱の温度上限は、通常
800°Cとされる。これは、鉄−炭素系の2元合金状
態図を見れば明らかなように、鉄が面心立方晶系から体
心立方晶系へと変態する温度、即ちα1変態点〔738
°C〕を境に酸素窒素、硫黄、炭素等の微量元素の移動
(マイグレーション)が起きて脱ガス現象を引き起こす
ことと密接に関わりがある。固相内拡散及び粒界移動に
よる脱ガスまでを考慮すれば、800°Cは、明らかに
成分分析に影響しないための前処理加熱温度の上限とな
る。また、α1変態点〔738°C〕を超過してキュー
リー温度〔768°C〕にまで加熱されても、高周波加
熱工程は数秒から数十秒間の短時間の加熱なので元素移
動速度が律速条件となり、棒鋼内部からの揮発性元素の
脱ガス量は僅少であることが、実験的に立証されてい
る。Moreover, the components contained in the steel bar, oxygen, nitrogen,
The upper limit of the temperature of the high frequency induction heating for facilitating the shaping of a steel bar sample for analyzing the concentration of elements such as sulfur and carbon is usually 800 ° C. As is clear from the iron-carbon binary alloy phase diagram, this is the temperature at which iron transforms from the face-centered cubic system to the body-centered cubic system, that is, the α1 transformation point [738
It is closely related to the movement of trace elements such as oxygen nitrogen, sulfur and carbon (migration) at the temperature of [° C] to cause the degassing phenomenon. Considering even diffusion in the solid phase and degassing due to grain boundary migration, 800 ° C is the upper limit of the pretreatment heating temperature, which obviously does not affect the component analysis. Also, even if the α1 transformation point [738 ° C] is exceeded and the Curie temperature [768 ° C] is exceeded, the high-frequency heating process is a heating for a short time of several seconds to several tens of seconds, so that the element transfer rate is a rate-determining condition. It has been experimentally proved that the degassing amount of volatile elements from the inside of a steel bar is small.
【0010】鋼材においては、キューリー温度TCを確
実に検出することによって、危険な過剰加熱を確実に回
避しつつ十分な軟化温度まで確実に加熱することが可能
となることが、以上の説明から容易に理解できよう。From the above description, it is possible to reliably heat the steel material to a sufficient softening temperature while surely avoiding dangerous overheating by surely detecting the Curie temperature T C. Easy to understand.
【0011】[0011]
【発明の効果】以上説明したとおり、本発明によれば、
接触式温度計と同等な加熱上限温度管理精度が、温度計
無しで達成できる。As described above, according to the present invention,
The heating upper limit temperature control accuracy equivalent to that of the contact type thermometer can be achieved without the thermometer.
【図1】本発明の実施例を示す図である。FIG. 1 is a diagram showing an embodiment of the present invention.
【図2】本発明の原理を説明する図である。FIG. 2 is a diagram illustrating the principle of the present invention.
1 発振器 2 インピーダンス整合回路 3 誘導加熱コイル 4 棒鋼 5 出力電流計 6 演算制御部 1 Oscillator 2 Impedance matching circuit 3 Induction heating coil 4 Steel bar 5 Output ammeter 6 Arithmetic control unit
Claims (2)
温度TCを検出して高周波加熱物体の加熱終点とする演
算制御部を設けたことを特徴とする温度制御装置。1. A temperature control device comprising a calculation control unit for detecting a Curie temperature T C at which a ferromagnetism is converted to a paramagnetism and setting the heating end point of a high-frequency heating object.
熱物体の加熱温度を目的温度に保持する演算制御部を設
けたことを特徴とする温度制御装置。2. A temperature control device comprising a calculation control unit for detecting the Curie temperature T C and maintaining the heating temperature of the high-frequency heating object at a target temperature.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP6011351A JPH07197135A (en) | 1994-01-07 | 1994-01-07 | Temperature controller |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP6011351A JPH07197135A (en) | 1994-01-07 | 1994-01-07 | Temperature controller |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH07197135A true JPH07197135A (en) | 1995-08-01 |
Family
ID=11775623
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP6011351A Withdrawn JPH07197135A (en) | 1994-01-07 | 1994-01-07 | Temperature controller |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH07197135A (en) |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2006206927A (en) * | 2005-01-25 | 2006-08-10 | Jfe Steel Kk | Heat treatment method for steel material |
JP2009125801A (en) * | 2007-11-28 | 2009-06-11 | Nissan Motor Co Ltd | Welding method |
US8481891B2 (en) | 2006-09-29 | 2013-07-09 | Koninklijke Philips Electronics N.V. | Induction ironing system |
JP2016110058A (en) * | 2014-11-27 | 2016-06-20 | 株式会社東芝 | Fixing device |
JP2017002372A (en) * | 2015-06-12 | 2017-01-05 | 富士電子工業株式会社 | Manufacturing method and heat treating method of cast, and high frequency quenching device |
JP2021042464A (en) * | 2020-05-08 | 2021-03-18 | 中外炉工業株式会社 | Control method of continuous heat treatment facility |
WO2021225078A1 (en) * | 2020-05-08 | 2021-11-11 | 中外炉工業株式会社 | Method for controlling continuous heat treatment equipment |
-
1994
- 1994-01-07 JP JP6011351A patent/JPH07197135A/en not_active Withdrawn
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2006206927A (en) * | 2005-01-25 | 2006-08-10 | Jfe Steel Kk | Heat treatment method for steel material |
US8481891B2 (en) | 2006-09-29 | 2013-07-09 | Koninklijke Philips Electronics N.V. | Induction ironing system |
JP2009125801A (en) * | 2007-11-28 | 2009-06-11 | Nissan Motor Co Ltd | Welding method |
JP2016110058A (en) * | 2014-11-27 | 2016-06-20 | 株式会社東芝 | Fixing device |
JP2017002372A (en) * | 2015-06-12 | 2017-01-05 | 富士電子工業株式会社 | Manufacturing method and heat treating method of cast, and high frequency quenching device |
JP2021042464A (en) * | 2020-05-08 | 2021-03-18 | 中外炉工業株式会社 | Control method of continuous heat treatment facility |
WO2021225078A1 (en) * | 2020-05-08 | 2021-11-11 | 中外炉工業株式会社 | Method for controlling continuous heat treatment equipment |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
A300 | Withdrawal of application because of no request for examination |
Free format text: JAPANESE INTERMEDIATE CODE: A300 Effective date: 20010403 |