JPH02166234A - Method for continuously annealing steel sheet - Google Patents
Method for continuously annealing steel sheetInfo
- Publication number
- JPH02166234A JPH02166234A JP63320849A JP32084988A JPH02166234A JP H02166234 A JPH02166234 A JP H02166234A JP 63320849 A JP63320849 A JP 63320849A JP 32084988 A JP32084988 A JP 32084988A JP H02166234 A JPH02166234 A JP H02166234A
- Authority
- JP
- Japan
- Prior art keywords
- temp
- induction heating
- heating zone
- steel sheet
- 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.)
- Pending
Links
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 23
- 239000010959 steel Substances 0.000 title claims abstract description 23
- 238000000137 annealing Methods 0.000 title claims abstract description 19
- 238000000034 method Methods 0.000 title claims description 18
- 238000010438 heat treatment Methods 0.000 claims abstract description 46
- 230000006698 induction Effects 0.000 claims abstract description 14
- 239000000446 fuel Substances 0.000 abstract description 4
- 238000001816 cooling Methods 0.000 description 7
- 238000007716 flux method Methods 0.000 description 3
- 230000003647 oxidation Effects 0.000 description 3
- 238000007254 oxidation reaction Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 239000002436 steel type Substances 0.000 description 2
- 229910001209 Low-carbon steel Inorganic materials 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 239000000295 fuel oil Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
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
- Heat Treatment Of Strip Materials And Filament Materials (AREA)
- Control Of Heat Treatment Processes (AREA)
Abstract
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、鋼板の連続焼鈍方法に関する。[Detailed description of the invention] [Industrial application field] The present invention relates to a continuous annealing method for steel plates.
連続焼鈍方法では、一般に加熱装置としてラジアントチ
ューブを用いることが多く、通常１０数パス掛けて鋼板
を７００〜８５０℃に加熱・均熱し、その後冷却すると
いうヒートパターンを用いて熱処理を行っている。そし
て、この方法により焼鈍を行うと、従来パッチ式焼鈍で
数十時間要していた処理を僅か十数分間で行うことがで
きる。しかし、特性面や品質面から見ると、バッチ式レ
ベルに十分達しておらず、このレベルに達することが重
要な課題となっている。そして、この解決策としては高
温焼鈍することが有望視されている。In the continuous annealing method, a radiant tube is generally used as a heating device, and heat treatment is performed using a heat pattern in which the steel plate is heated and soaked to 700 to 850° C. over 10 passes, and then cooled. When annealing is performed using this method, a process that conventionally required several tens of hours in patch annealing can be performed in just ten minutes. However, in terms of characteristics and quality, it has not fully reached the batch-type level, and reaching this level is an important issue. As a solution to this problem, high-temperature annealing is considered to be a promising solution.
しかし、従来用いていたラジアントチューブにより高温
焼鈍を行おうとすると、ラジアントチューブでは加熱速
度が８〜ｂ
ス長を長くする必要もあるため、設備が大型化し、設備
費が高くつく。また、ラジアントチューブには、従来よ
りチューブの孔空ざやメンテナンス上の問題もあったの
で、更に高温にすると、その傾向が一層酷くなる。そこ
で、最近においては、問題の多いラジアントチューブに
替えて熱効率に優れた直火還元加熱が用いられつつある
。However, if high-temperature annealing is to be performed using a conventionally used radiant tube, the heating rate of the radiant tube must be increased by 8 to 100 m. Since the length of the radiant tube must be increased, the equipment becomes larger and the equipment cost increases. In addition, radiant tubes have traditionally had problems with tube porosity and maintenance, and this tendency becomes even more severe when the temperature is raised further. Therefore, recently, direct flame reduction heating, which has excellent thermal efficiency, is being used instead of radiant tubes, which have many problems.
直火還元加熱は鋼板を直接加熱する方法であり、同じ温
度に加熱するならばラジアントチューブの１／ｌＯ以下
の時間で済む。したがって、設備もコンパクトになるが
、７５０°Ｃ以上の高温域では遊離０２によらずともＣ
Ｏ２やＨ２０による酸化が予想されるため、その調整が
難しい。Direct flame reduction heating is a method of directly heating a steel plate, and if heated to the same temperature, it takes less than 1/1O of the time required for a radiant tube. Therefore, the equipment becomes compact, but in the high temperature range of 750°C or higher, C
Since oxidation by O2 and H20 is expected, its adjustment is difficult.
そこで、本発明の目的は、上記課題を解決した鋼板の連
続焼鈍方法を提供することにある。SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a continuous annealing method for steel plates that solves the above problems.
上記目的を達成するため、本発明は、鋼板の連続焼鈍方
法において、鋼板温度が６００〜７００℃に達する低温
域と８００〜９００°Ｃに達する高温域とに分け、低温
域で直火還元加熱、高温域で誘導加熱を行い、低温域を
出た鋼板温度を測定して高温域で目標加熱温度に成るよ
う加熱制御することを特徴とする。In order to achieve the above object, the present invention provides a method for continuous annealing of steel plates, in which the steel plate temperature is divided into a low temperature range reaching 600 to 700°C and a high temperature range reaching 800 to 900°C, and direct flame reduction heating is performed in the low temperature range. The method is characterized in that induction heating is performed in a high temperature range, the temperature of the steel plate is measured after it leaves the low temperature range, and heating is controlled so that the target heating temperature is achieved in the high temperature range.
本発明においては、電流制御をすればよいので高温域で
の調整がし易く、しかも無酸化で鋼板を８００〜９００
℃に加熱することができるため、バッチ式に匹敵した焼
鈍を行うことができる。また、加熱速度も直火還元加熱
と変わらないので、高温域を誘導加熱に替えたとしても
炉長が長くなることもない。In the present invention, since it is only necessary to control the current, it is easy to adjust in the high temperature range, and furthermore, the steel plate can be heated to 800~900 without oxidation.
Since it can be heated to ℃, it is possible to perform annealing comparable to batch-type annealing. Furthermore, since the heating rate is the same as direct-fire reduction heating, even if the high-temperature region is replaced with induction heating, the furnace length will not become longer.
以下、本発明について更に詳しく説明する。 The present invention will be explained in more detail below.
本発明は、第１図に示すように、加熱帯１を低温域２と
高温域３とに分け、低温域２で直火還元加熱、高温域３
で誘導加熱を行うようにしたものである。直火還元加熱
は、一般に知られているように他の加熱法に比べ、設備
費用、ランニングコストが安く又加熱速度も従来一般に
用いられているラジアントチューブよりも１０倍速い。As shown in FIG. 1, the present invention divides a heating zone 1 into a low-temperature zone 2 and a high-temperature zone 3.
It is designed to perform induction heating. As is generally known, direct flame reduction heating has lower equipment costs and running costs than other heating methods, and the heating rate is 10 times faster than the conventionally commonly used radiant tube.
したがって、炉長を１／１０にすることができるが、こ
の方法により７５０℃以上に加熱すると、遊離０２がな
くてもＣ０２やＨ２０により鋼板表面が酸化する。そこ
で本発明においては、低温域２の加熱を６００〜７００
°Ｃに限るようにしている。そして、直火加熱は炉壁に
沿って配した多数のバーナ２ａ・により行われるが、こ
の場合バーナ先端より延びる火炎が酸化炎とならないよ
うに空燃比が１．０以下にされる。そして、燃焼に用い
る燃料には可燃ガスか重油を用い、空気との混合方式に
は予混合方式かバーナ先端混合方式が用いられる。Therefore, the furnace length can be reduced to 1/10, but when heated to 750° C. or higher using this method, the surface of the steel sheet is oxidized by CO2 and H20 even in the absence of free O2. Therefore, in the present invention, heating in low temperature range 2 is performed at 600 to 700
I try to limit it to °C. Direct flame heating is performed by a large number of burners 2a disposed along the furnace wall, but in this case the air-fuel ratio is set to 1.0 or less so that the flame extending from the tip of the burner does not turn into an oxidizing flame. Combustible gas or heavy oil is used as the fuel for combustion, and a premixing method or a burner tip mixing method is used for mixing with air.
一方、誘導加熱は、設備費やランニングコストが直火還
元加熱に比べて高くつくが、無酸化で直火並みの加熱速
度が得られるため、炉長を長くすることなく８００℃以
上の加熱が可能である。そこで、高温域３では、直火還
元加熱に替えて誘導加熱が用いられる。誘導加熱は主と
して焼入に用いられており、例えば平板を連続焼入する
場合には、一般に横軸磁束方式と縦軸磁束方式の二通り
が行われているが、本発明においてはどちらでもよいが
、鋼板Ｓを８００〜９００℃に加熱する必要があるため
、できれば縦軸磁束方式の方が有利である。On the other hand, although induction heating has higher equipment costs and running costs than direct flame reduction heating, it does not oxidize and can achieve heating speeds comparable to direct flame, so it can heat over 800℃ without increasing the furnace length. It is possible. Therefore, in the high temperature region 3, induction heating is used instead of direct flame reduction heating. Induction heating is mainly used for hardening, and for example, when continuously hardening a flat plate, two methods are generally used: horizontal magnetic flux method and vertical magnetic flux method, but in the present invention, either method may be used. However, since it is necessary to heat the steel plate S to 800 to 900°C, the vertical axis magnetic flux method is more advantageous if possible.
そして、連続焼鈍においては鋼板３がハースロール４に
より折り返し走行するので誘導子３ａ、・・・も鋼板３
の走行路に沿って配置される。この場合、種々のヒート
パターンに対応できるように誘導子３ａ、・・・を分散
させて配置することが望ましい。During continuous annealing, the steel plate 3 is turned around by the hearth roll 4, so that the inductors 3a, . . .
located along the driving route. In this case, it is desirable to arrange the inductors 3a, . . . in a distributed manner so as to correspond to various heat patterns.
また、電源装置３ｂにはサイリスクインバータが用いら
れ、板厚にあった周波数が選定される。Further, a silice inverter is used for the power supply device 3b, and a frequency suitable for the board thickness is selected.
また、この方法による場合には、電流制御もしくは周波
数制御により鋼板Ｓに発生する熱量を自由にコントロー
ルでき、炉の時定数も低く抑えることができる。したが
って、直火還元加熱で温度制御するよりも制御がし易い
。本発明においては、この利点を生かして、高温域３の
入側と出側にそれぞれ、鋼板Ｓの温度を計測する板温計
３ｃ、３ｄを配し、その計測値に基づいて高温域３の温
度を制御するようにしている。制御は電流制御ないし周
波数制御であってもよい。そして、画板温計３ｃ、３ｄ
により計測された温度は温度制御装置３ｅに入力され、
予め入力されたヒートパターンと比較される。例えばヒ
ートパターンの一例を示すと、高温焼鈍においては、鋼
種により第２図のような態様が考えられる。図中、６５
０°Ｃ以下の加熱は直火還元加熱、６５０°Ｃ以上の加
熱は誘導加熱である。ここで制御量が決定されると、そ
の制御量に基づいて各誘導子３ａ、 ・・に流す電流
ないし周波数が制御される。Moreover, in the case of this method, the amount of heat generated in the steel plate S can be freely controlled by current control or frequency control, and the time constant of the furnace can also be kept low. Therefore, it is easier to control the temperature than by direct flame reduction heating. In the present invention, taking advantage of this advantage, plate thermometers 3c and 3d for measuring the temperature of the steel plate S are arranged on the inlet and outlet sides of the high temperature zone 3, respectively, and based on the measured values, the temperature of the high temperature zone 3 is I try to control the temperature. The control may be current control or frequency control. And drawing board thermometers 3c, 3d
The temperature measured by is input to the temperature control device 3e,
It is compared with a heat pattern input in advance. For example, as an example of the heat pattern, in high-temperature annealing, the mode shown in FIG. 2 can be considered depending on the steel type. In the figure, 65
Heating below 0°C is direct flame reduction heating, and heating above 650°C is induction heating. Once the control amount is determined here, the current or frequency flowing through each inductor 3a, . . . is controlled based on the control amount.
加熱後の冷却は、−射的に液体冷却、ガスジェット冷却
、ロール冷却、気水冷却のいずれかにより行われる。ま
た、冷却速度は５０〜ｂ行い、冷却終点温度は鋼種によ
り過時効処理するもであれば４５０°Ｃ１又極低炭素鋼
で過時効処理の必要でないものであれば常温まで冷却す
る。Cooling after heating is carried out by any one of liquid cooling, gas jet cooling, roll cooling, and air/water cooling. In addition, the cooling rate is 50 - b, and the cooling end point temperature is 450°C1 depending on the steel type if overaging treatment is to be performed, or to room temperature if the steel is an extremely low carbon steel and does not require overaging treatment.
以上説明したように、本発明によれば設備のコンパクト
が図れると同時に無酸化でバッチ式に匹敵した焼鈍を行
うことができる。As explained above, according to the present invention, the equipment can be made more compact, and at the same time, it is possible to perform annealing comparable to batch type annealing without oxidation.
第１図は本発明の実施に用いられる装置のブロック図、
第２図は本発明で実施されるヒートパターンの一例を示
したパターン図である。
１・・・加熱帯、２・・低温域、２ａ・・・バーナ、３
高温域、３ａ・・・誘導子、３ｂ・・・電源装置、３ｃ
。
３ｄ・・・板温計、３ｅ・・・温度制御装置。FIG. 1 is a block diagram of an apparatus used to implement the present invention;
FIG. 2 is a pattern diagram showing an example of a heat pattern implemented in the present invention. 1...Heating zone, 2...Low temperature range, 2a...Burner, 3
High temperature range, 3a...inductor, 3b...power supply device, 3c
. 3d...Plate thermometer, 3e...Temperature control device.
Claims (1)
〜７００℃に達する低温域と８００〜９００℃に達する
高温域とに分け、低温域で直火還元加熱、高温域で誘導
加熱を行い、低温域を出た鋼板温度を測定して高温域で
目標加熱温度に成るよう加熱制御することを特徴とする
鋼板の連続焼鈍方法(1) In the continuous annealing method for steel plates, the steel plate temperature is 600
Divided into a low temperature range reaching ~700°C and a high temperature range reaching 800-900°C, direct fire reduction heating is performed in the low temperature range, induction heating is performed in the high temperature range, and the temperature of the steel plate when it exits the low temperature range is measured. Continuous annealing method for steel plate characterized by controlling heating to reach a target heating temperature
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63320849A JPH02166234A (en) | 1988-12-20 | 1988-12-20 | Method for continuously annealing steel sheet |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63320849A JPH02166234A (en) | 1988-12-20 | 1988-12-20 | Method for continuously annealing steel sheet |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH02166234A true JPH02166234A (en) | 1990-06-26 |
Family
ID=18125932
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63320849A Pending JPH02166234A (en) | 1988-12-20 | 1988-12-20 | Method for continuously annealing steel sheet |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH02166234A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1997000975A1 (en) * | 1995-06-23 | 1997-01-09 | Nippon Steel Corporation | Method of continuous annealing of cold rolled steel plate and equipment therefor |
| CN107964643A (en) * | 2017-12-27 | 2018-04-27 | 安德里茨（中国）有限公司 | Hot-strip continuous hot galvanizing device and method |
-
1988
- 1988-12-20 JP JP63320849A patent/JPH02166234A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1997000975A1 (en) * | 1995-06-23 | 1997-01-09 | Nippon Steel Corporation | Method of continuous annealing of cold rolled steel plate and equipment therefor |
| CN107964643A (en) * | 2017-12-27 | 2018-04-27 | 安德里茨（中国）有限公司 | Hot-strip continuous hot galvanizing device and method |
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