JPH07258740A - Method and apparatus for continuous heating steel slab - Google Patents
Method and apparatus for continuous heating steel slabInfo
- Publication number
- JPH07258740A JPH07258740A JP6052313A JP5231394A JPH07258740A JP H07258740 A JPH07258740 A JP H07258740A JP 6052313 A JP6052313 A JP 6052313A JP 5231394 A JP5231394 A JP 5231394A JP H07258740 A JPH07258740 A JP H07258740A
- Authority
- JP
- Japan
- Prior art keywords
- furnace
- heating
- steel slab
- steel
- oxide scale
- 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
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
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E20/00—Combustion technologies with mitigation potential
- Y02E20/34—Indirect CO2mitigation, i.e. by acting on non CO2directly related matters of the process, e.g. pre-heating or heat recovery
Landscapes
- Gas Burners (AREA)
- Pre-Mixing And Non-Premixing Gas Burner (AREA)
- Control Of Heat Treatment Processes (AREA)
- Tunnel Furnaces (AREA)
- Furnace Details (AREA)
Abstract
Description
【0001】[0001]
【産業上の利用分野】本発明は、スラブやビレット等の
鋼片を連続的に加熱する方法および装置に関するもので
ある。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for continuously heating steel slabs such as slabs and billets.
【0002】[0002]
【従来の技術】スラブやビレット等の鋼片に熱間圧延等
の加工を行う際の加熱には、鋼片を連続的に通過させ、
燃焼バーナにより所定温度に加熱する連続加熱炉が一般
に使用される。従来、鋼片の連続加熱炉においては、鋼
片を所定温度に均一に加熱するために在炉時間を長くし
ており、鋼片の表面には厚い酸化スケールが生じてい
た。厚い酸化スケールは、一部が炉内やその周辺に堆積
して環境を悪化したり、鋼材の製造歩留まり低下といっ
た問題を生じていたが、加熱前に存在した表面欠陥が酸
化により除去されるという利点も有しており、スケール
生成対策についてはあまり考慮されていなかった。2. Description of the Related Art When heating a steel slab such as a slab or billet during hot rolling, the steel slab is continuously passed through
A continuous heating furnace that heats to a predetermined temperature by a combustion burner is generally used. Conventionally, in a continuous heating furnace for billet, the in-furnace time is lengthened in order to uniformly heat the billet to a predetermined temperature, and a thick oxide scale is generated on the surface of the billet. Thick oxide scale had some problems such as being deposited in the furnace and its surroundings, deteriorating the environment and reducing the production yield of steel materials, but surface defects that existed before heating were removed by oxidation. It also has an advantage, and little attention was paid to measures against scale generation.
【0003】このような連続加熱炉の雰囲気に関する公
知文献としては、たとえば特開昭63−109118号
公報があり、バーナの燃焼用空気に酸素を富化させるこ
とで燃焼排ガス中の窒素酸化物を抑制することが記載さ
れているが、鋼片酸化スケールの生成については考慮さ
れていない。一方、連続加熱炉と連続鋳造設備をローラ
ーテーブル等で直結することにより、連続鋳造された高
温の鋼片を加熱炉に装入することが可能となった。また
加熱炉においても、燃焼バーナの改善等により加熱効率
が向上している。さらに、燃焼雰囲気を無酸素あるいは
低酸素雰囲気に調整することも可能である。したがっ
て、鋼片の加熱時間短縮や、加熱雰囲気の調整により、
酸化スケール生成の抑制が可能になっている。As a known document concerning the atmosphere of such a continuous heating furnace, there is, for example, Japanese Patent Laid-Open No. 63-109118, in which nitrogen oxide in combustion exhaust gas is removed by enriching combustion air of a burner with oxygen. Although it is described to suppress, the formation of billet oxide scale is not considered. On the other hand, by directly connecting the continuous heating furnace and the continuous casting equipment with a roller table or the like, it becomes possible to load the continuously cast high temperature steel slab into the heating furnace. Also in the heating furnace, the heating efficiency has been improved by improving the combustion burner. Furthermore, the combustion atmosphere can be adjusted to be oxygen-free or low-oxygen atmosphere. Therefore, by shortening the heating time of the billet and adjusting the heating atmosphere,
It is possible to suppress the generation of oxide scale.
【0004】加熱炉用の高効率燃焼バーナとして、蓄熱
式切換え燃焼バーナが実開平3−46742号公報等に
より知られている。このバーナは、図4の例に示すよう
に、一対のバーナ11,21および蓄熱器12,22が
空気切換弁15で連結されて構成されており、一方のバ
ーナ21が点火している間は、他方のバーナ11は炉内
の排ガスを吸引し蓄熱器12に熱を蓄えている。この
間、排ガスは連結管13を通り空気切換弁15を経て排
ガス管19から排気され、空気は空気管17から空気切
換弁15および連結管23を経て蓄熱器22に入り予熱
されてバーナ21に送られる。そして、所定のタイミン
グで空気切換弁15を矢印のように回動させ、バーナ1
1とバーナ21を交互に切換えて燃焼させる。燃料ガス
は、ガス導入管14および24から交互に導入される。As a high-efficiency combustion burner for a heating furnace, a heat storage type switching combustion burner is known from Japanese Utility Model Publication No. 3-46742. As shown in the example of FIG. 4, this burner is configured by connecting a pair of burners 11 and 21 and heat accumulators 12 and 22 with an air switching valve 15, and while one burner 21 is igniting. The other burner 11 sucks the exhaust gas in the furnace and stores heat in the regenerator 12. During this time, the exhaust gas passes through the connecting pipe 13 and is exhausted from the exhaust gas pipe 19 through the air switching valve 15, and the air enters the regenerator 22 through the air switching valve 15 and the connecting pipe 23 and is preheated and sent to the burner 21. To be Then, at a predetermined timing, the air switching valve 15 is rotated as shown by the arrow, and the burner 1
1 and the burner 21 are alternately switched to burn. Fuel gas is introduced alternately from the gas introduction pipes 14 and 24.
【0005】[0005]
【発明が解決しようとする課題】鋼片の連続加熱炉にお
いて、上記のように連続鋳造後の熱片を装入したり、あ
るいは高効率バーナを採用することで、短時間の加熱が
可能となり、また、炉内の雰囲気を調整して酸化スケー
ルの生成を抑制することも可能になっている。しかし、
連続鋳造技術が進歩したとはいえ、鋼片の表面欠陥を皆
無にすることは困難であるため、従来は連続加熱炉内で
酸化スケールを生成させるような加熱条件で操業を行
い、表面疵を酸化により除去していた。このため炉内に
スケールが堆積し、そのスケールにより鋼片に疵が発生
するという問題も生じた。本発明は、スラブやビレット
等の鋼片を燃焼バーナにより連続的に加熱する工程にお
いて、加熱時の酸化スケール生成を抑え、加熱後に鋼片
を酸化させて剥離性のよいスケールを生成し表面欠陥を
除去するとともに、加熱炉内へのスケール堆積の問題も
解決した方法および装置の提供を目的とする。In the continuous heating furnace for steel slabs, it is possible to heat in a short time by charging the hot slabs after continuous casting as described above or by using a high efficiency burner. Moreover, it is possible to suppress the production of oxide scale by adjusting the atmosphere in the furnace. But,
Although continuous casting technology has progressed, it is difficult to eliminate surface defects on steel slabs.Therefore, in the past, operation was carried out in a continuous heating furnace under heating conditions that generated oxide scale, and surface defects were It was removed by oxidation. For this reason, there is a problem in that scale is deposited in the furnace, and the scale causes flaws in the steel slab. The present invention, in the step of continuously heating steel slabs such as slabs and billets with a combustion burner, suppresses the formation of oxidized scale during heating, and oxidizes the steel slabs after heating to produce scale with good peelability and surface defects. It is an object of the present invention to provide a method and an apparatus which eliminates the above and solves the problem of scale deposition in a heating furnace.
【0006】[0006]
【課題を解決するための手段】上記目的を達成するため
の本発明法は、連続加熱炉内に鋼片をつぎつぎと通過さ
せ、燃焼バーナにより所定温度に加熱する方法におい
て、鋼片の酸化スケール生成を抑えた条件で鋼片を加熱
するとともに、加熱後の鋼片に炉内の出口近傍にて酸化
性ガスを吹き付けることを特徴とする鋼片の連続加熱方
法である。Means for Solving the Problems The method of the present invention for achieving the above-mentioned object is a method of passing steel pieces one after another in a continuous heating furnace and heating them to a predetermined temperature by a combustion burner, in which an oxide scale of the steel pieces is obtained. It is a continuous heating method for a steel slab, characterized in that the steel slab is heated under the condition that the generation is suppressed, and an oxidizing gas is blown to the heated steel slab near the outlet in the furnace.
【0007】また本発明装置は、鋼片をつぎつぎと通過
させ、燃焼バーナにより所定温度に加熱する連続加熱炉
において、酸化スケール生成を抑えた加熱手段を設ける
とともに、酸化性ガスを鋼片に吹き付けるノズルを炉内
の出口近傍に設け、かつ炉外の燃焼排ガス経路に熱交換
器を付設し、該熱交換器で加熱された酸化性ガスを前記
ノズルに導く配管を設けたことを特徴とする鋼片の連続
加熱装置である。そして、加熱手段が蓄熱式切換え燃焼
バーナであることが好ましい。Further, the apparatus of the present invention is provided with a heating means for suppressing the formation of oxide scale in a continuous heating furnace in which steel pieces are passed through one after another and heated to a predetermined temperature by a combustion burner, and an oxidizing gas is sprayed on the steel pieces. A nozzle is provided in the vicinity of the outlet in the furnace, a heat exchanger is attached to the combustion exhaust gas path outside the furnace, and a pipe for guiding the oxidizing gas heated by the heat exchanger to the nozzle is provided. It is a continuous heating device for billets. Further, it is preferable that the heating means is a heat storage type switching combustion burner.
【0008】[0008]
【作用】以下、図面により本発明を説明する。図1は本
発明の装置例を示すものであり、スラブ等の鋼片Sが、
連続加熱炉1内を矢印の方向すなわち図の右から左へ、
ウォーキングビーム(図示せず)等によりつぎつぎと搬
送され、燃焼バーナ2で所定温度に加熱される。炉内の
燃焼排ガスは、連続加熱炉1の出口に設けられたダクト
3から排出される。本発明法は、このような連続加熱炉
での鋼片の加熱方法において、鋼片の酸化スケール生成
を抑えた条件で加熱する。酸化スケール生成を抑えた条
件としては、前記図3のような公知の蓄熱式切り換え燃
焼バーナを使用して短時間加熱を行うこと、各種燃焼バ
ーナにおいて、空気比を下げ無酸素あるいは低酸素雰囲
気に調整すること、あるいは燃焼バーナの還元炎を鋼片
に直接当てること等を採用することができる。The present invention will be described below with reference to the drawings. FIG. 1 shows an example of an apparatus of the present invention, in which a steel slab S such as a slab is
In the continuous heating furnace 1, in the direction of the arrow, that is, from right to left in the figure,
It is conveyed one after another by a walking beam (not shown) or the like, and heated to a predetermined temperature by the combustion burner 2. The combustion exhaust gas in the furnace is discharged from a duct 3 provided at the outlet of the continuous heating furnace 1. According to the method of the present invention, in such a method for heating a steel slab in a continuous heating furnace, the steel slab is heated under the condition that generation of oxide scale is suppressed. As conditions for suppressing the generation of oxide scale, heating is performed for a short time by using a known regenerative combustion burner as shown in FIG. 3, and in various combustion burners, the air ratio is reduced to anoxic or low oxygen atmosphere. Adjustment or direct application of the reducing flame of the combustion burner to the billet can be adopted.
【0009】そして、本発明法はさらに、加熱された鋼
片Sに炉内の出口近傍にて酸化性ガスを吹き付ける。吹
き付けるノズル6は、鋼片Sの上面および下面に向け炉
の幅方向に複数個配置する。各ノズル6には、排ガスの
ダクト3に付設された熱交換器4から、配管5により高
温の酸化性ガスを供給している。酸化性ガスとしては、
水蒸気、高温の空気や酸素等を採用することができる。
このような本発明法によれば、加熱時の酸化スケール生
成が抑えられ、かつ所定温度に加熱された後の鋼片に
は、高温の酸化性ガスを吹き付けることにより酸化スケ
ールが生成する。その酸化スケールは、高温の酸化性ガ
ス雰囲気で生成を制御するため、均一で剥離性がよい。
そして、加熱前の鋼片に存在したヘゲやスリバー等の表
面疵の種類や深さに応じて吹き付け量を調整し、酸化ス
ケールの厚さをコントロールすることができる。酸化ス
ケールを生成させた鋼片は、炉外に抽出した後、熱間加
工前のスケールブレーカーによりスケールを剥離して表
面疵が除去される。Further, according to the method of the present invention, an oxidizing gas is blown onto the heated steel slab S in the vicinity of the outlet in the furnace. A plurality of nozzles 6 for spraying are arranged toward the upper surface and the lower surface of the steel slab S in the width direction of the furnace. A high temperature oxidizing gas is supplied to each nozzle 6 from a heat exchanger 4 attached to the exhaust gas duct 3 through a pipe 5. As oxidizing gas,
Steam, high temperature air, oxygen or the like can be used.
According to such a method of the present invention, generation of oxide scale during heating is suppressed, and oxide scale is generated by blowing a high-temperature oxidizing gas to the steel slab after being heated to a predetermined temperature. Since the generation of the oxide scale is controlled in a high temperature oxidizing gas atmosphere, it is uniform and has good peeling property.
The thickness of the oxide scale can be controlled by adjusting the spraying amount according to the type and depth of the surface flaws such as the beard and sliver existing in the steel piece before heating. The steel slab that has generated the oxide scale is extracted outside the furnace, and then the scale is peeled off by a scale breaker before hot working to remove surface flaws.
【0010】炉内の出口近傍で酸化スケールを生成させ
た鋼片は、炉外に抽出した後の搬送過程でスケールの一
部が脱落することがあっても、炉内でのスケール脱落は
殆ど生じないので、従来のように炉内にスケールが堆積
することはない。また、炉内の出口近傍において、燃焼
排ガスはダクト2に向けて鋼片Sの進行方向に流れるの
で、吹き付けた酸化性ガスは、炉内の加熱雰囲気には影
響を及ぼさず、加熱後の鋼片Sの表面にのみ作用する。With respect to the steel slab that has produced oxide scale near the outlet in the furnace, even if a part of the scale may fall off during the transportation process after extraction to the outside of the furnace, the scale will almost always fall off in the furnace. Since it does not occur, scale does not accumulate in the furnace as in the conventional case. Further, since the combustion exhaust gas flows toward the duct 2 in the traveling direction of the steel slab S near the outlet in the furnace, the sprayed oxidizing gas does not affect the heating atmosphere in the furnace, and the steel after heating is heated. It acts only on the surface of the piece S.
【0011】さらに本発明法は、図2のように排気用の
ダクト3を炉の入側に設置し、燃焼排ガスを鋼片Sの移
動方向(矢印の方向)と反対方向に流すことで熱効率を
向上させた加熱炉に適用することもできる。ただし、こ
の場合、吹き付けた酸化性ガスが炉の入側方向に拡散し
て炉内雰囲気が酸化性になるのを防ぐため、図2に示す
ような仕切り壁26を、ノズル6と炉尻にある燃焼バー
ナ2との間に設けるとともに、出口扉27を設け、酸化
性ガスの吹き付け方向を出口方向に傾斜させ、吹き付け
と同時に出口扉27を開け、吹き付け終了時に鋼片Sを
炉外に搬送するシステムを採用する。仕切り壁26およ
び開閉扉27には、耐火レンガやプラスチック耐火物を
採用することができる。また仕切り壁26には、この
他、ジルコニア系またはアルミナ系のセラミックファイ
バーによるスカート状の構造物も採用できる。Further, in the method of the present invention, as shown in FIG. 2, the exhaust duct 3 is installed on the inlet side of the furnace, and the combustion exhaust gas is caused to flow in the direction opposite to the moving direction (the direction of the arrow) of the steel slab S, thereby increasing the thermal efficiency. It can also be applied to a heating furnace with improved temperature. However, in this case, in order to prevent the sprayed oxidizing gas from diffusing in the inlet side direction of the furnace and oxidizing the atmosphere inside the furnace, a partition wall 26 as shown in FIG. The outlet door 27 is provided in addition to the one provided with the combustion burner 2, the oxidizing gas blowing direction is inclined to the outlet direction, the outlet door 27 is opened at the same time as the blowing, and the steel slab S is transported to the outside of the furnace at the end of the blowing. Adopt a system that does. For the partition wall 26 and the opening / closing door 27, refractory brick or plastic refractory can be adopted. Further, for the partition wall 26, a skirt-shaped structure made of zirconia-based or alumina-based ceramic fiber can also be used.
【0012】なお、本発明法において、酸化性ガス吹き
付け用のノズル6を鋼片の搬送方向と交差する方向に分
布させて設け、加熱炉装入前あるいは加熱炉内で鋼片の
表面疵の位置および種類を検出し、その検出結果に応じ
て、各ノズルからの酸化性ガス吹き付け量を制御するこ
とにより、酸化スケールの生成量を必要最小限にして表
面疵の除去を行うことができる。In the method of the present invention, the nozzles 6 for blowing an oxidizing gas are provided in a distributed manner in a direction intersecting with the conveying direction of the steel slab to remove surface flaws on the steel slab before charging in the heating furnace or in the heating furnace. By detecting the position and type and controlling the amount of oxidizing gas sprayed from each nozzle according to the detection result, it is possible to minimize the amount of oxide scale produced and remove surface defects.
【0013】つぎに、本発明装置は図1および図2の例
に示すような連続加熱炉1において、酸化スケール生成
を抑えた加熱手段を設けてある。酸化スケール生成を抑
えた加熱手段としては、燃焼バーナ2に、前記図4のよ
うな公知の蓄熱式切り換え燃焼バーナを採用するほか、
各種燃焼バーナにおいて、空気比を下げ無酸素あるいは
低酸素雰囲気に調整したもの、あるいは燃焼バーナの還
元炎が鋼片に直接当たるように配設したもの等を採用す
ることができる。Next, the apparatus of the present invention is provided with a heating means for suppressing the production of oxide scale in the continuous heating furnace 1 as shown in the examples of FIGS. 1 and 2. As a heating means that suppresses the generation of oxide scale, a known heat storage type switching combustion burner as shown in FIG. 4 is adopted as the combustion burner 2.
Among various combustion burners, those having a reduced air ratio and adjusted to an oxygen-free or low-oxygen atmosphere, or those arranged so that the reducing flame of the combustion burner directly hits the steel billet may be employed.
【0014】そして、本発明装置はさらに、図1および
図2のダクト3のような炉外の燃焼排ガス経路に熱交換
器4を付設し、酸化性ガスを鋼片Sに吹き付けるノズル
6を炉内の出口近傍に設け、熱交換器4で加熱された酸
化性ガスをノズル6に導く配管5を設けている。ノズル
6は、鋼片Sの上下に、鋼片の搬送方向と交差する方向
に分布させて設け、鋼片Sの全面に酸化性ガスを吹き付
けるようにする。そして、連続加熱炉1の前面あるいは
炉内に鋼片Sの疵検出装置を設け、検出結果に応じて各
ノズル6からの酸化性ガス吹き付け量を制御することも
できる。Further, in the apparatus of the present invention, a heat exchanger 4 is attached to a combustion exhaust gas path outside the furnace such as the duct 3 of FIGS. 1 and 2, and a nozzle 6 for blowing an oxidizing gas to the steel slab S is installed in the furnace. A pipe 5 is provided in the vicinity of the outlet of the inside to guide the oxidizing gas heated by the heat exchanger 4 to the nozzle 6. The nozzles 6 are provided above and below the steel slab S so as to be distributed in a direction intersecting the transportation direction of the steel slab so that the oxidizing gas is blown onto the entire surface of the steel slab S. It is also possible to provide a flaw detection device for the steel slab S on the front surface of the continuous heating furnace 1 or in the furnace, and control the amount of oxidizing gas sprayed from each nozzle 6 according to the detection result.
【0015】また、本発明装置において、加熱手段とし
て蓄熱式切り換え燃焼バーナを採用した例を図3に示
す。連続加熱炉1内を矢印の方向に搬送される鋼片Sの
上下に、蓄熱式切り換え燃焼バーナ7および8を複数
(図では各4個示す)配設してある。各蓄熱式切り換え
燃焼バーナ7および8は、それぞれ、バーナ11,21
および蓄熱器12,22を有し、連結管13,23と空
気切換弁15、およびガス導入管14,24とガス切換
弁16で連結されている。空気切換弁15は空気調整弁
20を経て空気管17に接続し、ガス切換弁16はガス
調整弁25を経てガス管18に接続している。両切換弁
15,16は、同時に作動して蓄熱器式切り換え燃焼バ
ーナ7と8を交互に燃焼させる。FIG. 3 shows an example in which a heat storage type switching combustion burner is used as the heating means in the apparatus of the present invention. A plurality of heat storage type switching combustion burners 7 and 8 (four in each figure are shown) are arranged above and below a steel slab S conveyed in the continuous heating furnace 1 in the direction of the arrow. The heat storage type switching combustion burners 7 and 8 are respectively burners 11 and 21.
And the heat accumulators 12 and 22, and are connected by the connecting pipes 13 and 23 to the air switching valve 15 and the gas introducing pipes 14 and 24 to the gas switching valve 16. The air switching valve 15 is connected to the air pipe 17 via the air adjusting valve 20, and the gas switching valve 16 is connected to the gas pipe 18 via the gas adjusting valve 25. Both switching valves 15 and 16 operate at the same time to alternately combust the regenerative switching combustion burners 7 and 8.
【0016】上方の燃焼バーナ1を燃焼させるときは、
燃料ガスはガス管18から、ガス調整弁25、ガス切換
弁16、およびガス導入管14を経て燃焼バーナ7に供
給され、空気は空気管17から空気調整弁20、空気切
換弁15、および連結管13を経て燃焼バーナ7に供給
され、蓄熱器12で予熱される。この間、下方の燃焼バ
ーナ8では炉内の排ガスを吸引し、蓄熱器22に熱を蓄
え、空気切換弁15を経て排ガス管19に導いている。
排ガス管19の経路には熱交換器4が付設してあり、配
管5を通して高温の酸化性ガスを鋼片Sに吹き付けるノ
ズル6が炉内の出口近傍に設けてある。When burning the upper combustion burner 1,
Fuel gas is supplied from the gas pipe 18 to the combustion burner 7 via the gas regulating valve 25, the gas switching valve 16 and the gas introducing pipe 14, and the air is fed from the air pipe 17 to the air regulating valve 20, the air switching valve 15 and the connection. It is supplied to the combustion burner 7 via the pipe 13 and preheated in the heat storage device 12. During this time, the lower combustion burner 8 sucks the exhaust gas in the furnace, stores heat in the heat storage device 22, and guides it to the exhaust gas pipe 19 via the air switching valve 15.
A heat exchanger 4 is attached to the path of the exhaust gas pipe 19, and a nozzle 6 for blowing a high temperature oxidizing gas to the steel slab S through a pipe 5 is provided near the outlet in the furnace.
【0017】炉内の温度調整は、あらかじめ得られた情
報に基づき、ガス調整弁25および空気調整弁20を作
動させて、燃料ガスおよび空気の供給量を調整して燃焼
制御を行う。また、燃料ガスおよび空気の供給量に応じ
た適正なタイミングで切換弁15,16を作動させ、両
燃焼バーナ7,8の燃焼切換えを行う。切換えのタイミ
ングは、蓄熱器12あるいは22の温度が飽和する時間
よりも短時間とするのが効果的である。The temperature inside the furnace is controlled by operating the gas adjusting valve 25 and the air adjusting valve 20 on the basis of the information obtained in advance to adjust the supply amounts of fuel gas and air to control combustion. Further, the switching valves 15 and 16 are operated at an appropriate timing according to the supply amounts of the fuel gas and the air to switch the combustion of both combustion burners 7 and 8. It is effective that the switching timing is shorter than the time when the temperature of the heat storage device 12 or 22 is saturated.
【0018】このような本発明装置においては、蓄熱式
切り換え燃焼バーナにより急速加熱を行うことができる
ので、加熱時には鋼片の酸化スケール生成が抑制され、
加熱後に疵の種類や深さに応じた厚さの酸化スケールを
生成できる。なお本発明において、蓄熱式切り換え燃焼
バーナを採用する場合、交互に燃焼させる燃焼バーナ
は、図3の例のように上下で対とするほか、連続加熱炉
1の両サイドで対にすることができ、また連続加熱炉1
の天井に燃焼バーナを設けて、天井のバーナ同士、ある
いは天井のバーナと側面のバーナを対にする等、炉の容
量や加熱温度に応じて各種の組み合わせを採用すること
ができる。In such an apparatus of the present invention, rapid heating can be carried out by the heat storage type switching combustion burner, so that during heating, generation of oxidized scale of the steel slab is suppressed,
After heating, an oxide scale having a thickness corresponding to the type and depth of the flaw can be produced. In the present invention, when the heat storage type switching combustion burner is adopted, the combustion burners alternately burned may be paired up and down as in the example of FIG. 3, or may be paired on both sides of the continuous heating furnace 1. Yes, continuous heating furnace 1
Various combinations can be adopted depending on the capacity and heating temperature of the furnace, for example, by providing combustion burners on the ceiling and pairing the burners on the ceiling, or pairing the burners on the ceiling and the side burners.
【0019】[0019]
【実施例】図1のような連続加熱炉において、蓄熱式切
換え燃焼バーナを採用して低酸素雰囲気で、軟鋼の連続
鋳造スラブを1000℃に加熱した後、炉出口にてスラ
ブの搬送方向と直交して約1mおきに設けたフルコーン
ノズルから、200〜300℃の水蒸気を20〜30m
/秒の流速で吹き付けた。炉から抽出したスラブの表面
には、全面に酸化スケールが生成しており、炉内では剥
離せず、抽出後のスケールブレーカーで全面が容易に剥
離した。加熱前のスラブの表面疵を観察しておき、表面
疵の種類および深さに応じて吹き付け時間を調整した結
果、スケール剥離後のスラブには表面疵が観察されなか
った。EXAMPLE In a continuous heating furnace as shown in FIG. 1, a mild steel continuous cast slab was heated to 1000 ° C. in a low oxygen atmosphere by adopting a heat storage type switching combustion burner, and then at the furnace outlet, the slab conveying direction was changed. Water vapor at 200-300 ° C for 20-30m from a full cone nozzle installed orthogonally every 1m.
Sprayed at a flow rate of / sec. Oxide scale was formed on the entire surface of the slab extracted from the furnace, and it did not peel off in the furnace, and the entire surface was easily peeled off by the scale breaker after extraction. As a result of observing the surface defects of the slab before heating and adjusting the spraying time according to the type and depth of the surface defects, no surface defects were observed in the slab after scale peeling.
【0020】[0020]
【発明の効果】本発明によれば、スラブやビレット等の
鋼片を連続加熱炉で燃焼バーナにより加熱する工程にお
いて、加熱時には酸化スケール生成が抑制され、加熱後
に炉出口にて酸化スケールを厚さを調整して生成させる
ことができる。生成した酸化スケールは剥離性がよく、
スラブの表面疵をスケールとして容易に除去することが
でき、また表面疵の種類や深さに応じて、部分的にスケ
ールの厚さをコントロールできるので、スケールロスに
よる歩留まり低下が最小限に抑えられる。生成したスケ
ールは、炉内では剥離し難いので、加熱炉内へのスケー
ル堆積の問題もない。さらに、炉の出口で酸化スケール
を生成するため、炉内でのスケール層による加熱ロスは
ない。According to the present invention, in the step of heating a steel slab such as a slab or billet with a combustion burner in a continuous heating furnace, the production of oxide scale is suppressed during heating, and the oxide scale is thickened at the furnace outlet after heating. It can be generated by adjusting the height. The produced oxide scale has good peelability,
Surface defects of slabs can be easily removed as scales, and the thickness of scales can be partially controlled according to the type and depth of surface defects, thus minimizing yield loss due to scale loss. . Since the generated scale is difficult to peel in the furnace, there is no problem of scale deposition in the heating furnace. Further, since oxide scale is generated at the outlet of the furnace, there is no heating loss due to the scale layer in the furnace.
【図1】本発明装置の例を示す縦断面図である。FIG. 1 is a vertical sectional view showing an example of a device of the present invention.
【図2】本発明装置の別の例を示す縦断面図である。FIG. 2 is a vertical cross-sectional view showing another example of the device of the present invention.
【図3】本発明装置の別の例を示す縦断面図である。FIG. 3 is a vertical cross-sectional view showing another example of the device of the present invention.
【図4】公知の蓄熱式切換え燃焼バーナの断面図であ
る。FIG. 4 is a cross-sectional view of a known heat storage type switching combustion burner.
1:連続加熱炉 2:燃焼バーナ 3:ダクト 4:熱交換器 5:配管 6:ノズル 7,8:蓄熱式切換え燃焼バーナ 10:炉壁 11,21:バーナ 12,22:蓄熱器 13,23:連結管 14,24:ガス導入管 15:空気切換弁 16:ガス切換弁 17:空気管 18:ガス管 19:排ガス管 20:空気調整弁 25:ガス調整弁 26:仕切り壁 27:開閉扉 S:鋼片 1: Continuous heating furnace 2: Combustion burner 3: Duct 4: Heat exchanger 5: Piping 6: Nozzle 7,8: Heat storage type switching combustion burner 10: Furnace wall 11,21: Burner 12,22: Heat storage device 13, 23 : Connection pipes 14, 24: Gas introduction pipes 15: Air switching valve 16: Gas switching valve 17: Air pipe 18: Gas pipe 19: Exhaust gas pipe 20: Air adjusting valve 25: Gas adjusting valve 26: Partition wall 27: Open / close door S: Steel billet
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 庁内整理番号 FI 技術表示箇所 F23D 14/66 B F27B 9/04 F27D 7/02 A 7727−4K ─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. 6 Identification code Internal reference number FI Technical display location F23D 14/66 B F27B 9/04 F27D 7/02 A 7727-4K
Claims (3)
せ、燃焼バーナにより所定温度に加熱する方法におい
て、鋼片の酸化スケール生成を抑えた条件で鋼片を加熱
するとともに、加熱後の鋼片に炉内の出口近傍にて酸化
性ガスを吹き付けることを特徴とする鋼片の連続加熱方
法。1. A method in which steel billets are passed through a continuous heating furnace one after another and heated to a predetermined temperature by a combustion burner, wherein the billet is heated under the condition that the oxide scale formation of the billet is suppressed and A continuous heating method for a steel slab, which comprises spraying an oxidizing gas on the steel slab near an outlet in a furnace.
により所定温度に加熱する連続加熱炉において、酸化ス
ケール生成を抑えた加熱手段を設けるとともに、酸化性
ガスを鋼片に吹き付けるノズルを炉内の出口近傍に設
け、かつ炉外の燃焼排ガス経路に熱交換器を付設し、該
熱交換器で加熱された酸化性ガスを前記ノズルに導く配
管を設けたことを特徴とする鋼片の連続加熱装置。2. A continuous heating furnace in which steel pieces are passed through one after another and heated to a predetermined temperature by a combustion burner, a heating means for suppressing generation of oxide scale is provided, and a nozzle for blowing an oxidizing gas to the steel pieces is provided in the furnace. Of the steel slab provided with a heat exchanger provided in the vicinity of the outlet of the furnace and attached to the combustion exhaust gas path outside the furnace, and a pipe for guiding the oxidizing gas heated by the heat exchanger to the nozzle. Heating device.
ることを特徴とする請求項2記載の鋼片の連続加熱装
置。3. The continuous heating device for billet according to claim 2, wherein the heating means is a regenerative combustion burner.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP6052313A JPH07258740A (en) | 1994-03-23 | 1994-03-23 | Method and apparatus for continuous heating steel slab |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP6052313A JPH07258740A (en) | 1994-03-23 | 1994-03-23 | Method and apparatus for continuous heating steel slab |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH07258740A true JPH07258740A (en) | 1995-10-09 |
Family
ID=12911301
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP6052313A Pending JPH07258740A (en) | 1994-03-23 | 1994-03-23 | Method and apparatus for continuous heating steel slab |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH07258740A (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2006266569A (en) * | 2005-03-23 | 2006-10-05 | Mitsubishi Electric Corp | Burning furnace and burning system with usage of it |
JP2021067437A (en) * | 2019-10-28 | 2021-04-30 | 中外炉工業株式会社 | Continuous heat treatment furnace |
-
1994
- 1994-03-23 JP JP6052313A patent/JPH07258740A/en active Pending
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2006266569A (en) * | 2005-03-23 | 2006-10-05 | Mitsubishi Electric Corp | Burning furnace and burning system with usage of it |
JP2021067437A (en) * | 2019-10-28 | 2021-04-30 | 中外炉工業株式会社 | Continuous heat treatment furnace |
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