JPH0472023A - Direct firing type continuous annealing method for steel strip and apparatus thereof - Google Patents
Direct firing type continuous annealing method for steel strip and apparatus thereofInfo
- Publication number
- JPH0472023A JPH0472023A JP18054790A JP18054790A JPH0472023A JP H0472023 A JPH0472023 A JP H0472023A JP 18054790 A JP18054790 A JP 18054790A JP 18054790 A JP18054790 A JP 18054790A JP H0472023 A JPH0472023 A JP H0472023A
- Authority
- JP
- Japan
- Prior art keywords
- steel strip
- heating zone
- exhaust gas
- direct
- zone
- 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.)
- Granted
Links
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 66
- 239000010959 steel Substances 0.000 title claims abstract description 66
- 238000000137 annealing Methods 0.000 title claims abstract description 20
- 238000000034 method Methods 0.000 title claims abstract description 18
- 238000010304 firing Methods 0.000 title abstract 6
- 238000010438 heat treatment Methods 0.000 claims abstract description 64
- 239000007789 gas Substances 0.000 claims abstract description 37
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 20
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 20
- 239000001301 oxygen Substances 0.000 claims abstract description 20
- 239000000567 combustion gas Substances 0.000 claims abstract description 16
- 238000001816 cooling Methods 0.000 claims abstract description 10
- 230000002829 reductive effect Effects 0.000 claims abstract description 8
- 230000002378 acidificating effect Effects 0.000 claims abstract 2
- 238000002791 soaking Methods 0.000 claims description 8
- 238000005485 electric heating Methods 0.000 claims description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 abstract description 28
- 229910052799 carbon Inorganic materials 0.000 abstract description 28
- 238000002485 combustion reaction Methods 0.000 abstract description 18
- 238000007664 blowing Methods 0.000 abstract description 4
- 230000001276 controlling effect Effects 0.000 abstract 1
- 230000001105 regulatory effect Effects 0.000 abstract 1
- 238000007747 plating Methods 0.000 description 7
- 230000000694 effects Effects 0.000 description 4
- 239000000446 fuel Substances 0.000 description 4
- 239000002737 fuel gas Substances 0.000 description 4
- 239000002436 steel type Substances 0.000 description 4
- 238000009792 diffusion process Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 238000004140 cleaning Methods 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 230000001590 oxidative effect Effects 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 239000000571 coke Substances 0.000 description 1
- 238000005097 cold rolling Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000005246 galvanizing Methods 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000010731 rolling oil Substances 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は鋼帯の連続焼鈍方法及びその焼鈍装置に関する
ものである。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a continuous annealing method for steel strips and an annealing apparatus therefor.
連続焼鈍装置の加熱方式として、ラジアントチューブを
利用した間接加熱方式と直火加熱方式が知られている。As heating methods for continuous annealing equipment, an indirect heating method using a radiant tube and a direct heating method are known.
このうち後者の直火加熱方式は、間接加熱方式に比較し
加熱能力に優れ、しかも冷間圧延油をバーンアウトでき
るためそのクリーニング設備を省略できる等の利点を有
しており、広く溶融亜鉛メツキラインや鋼板の連続焼鈍
ラインに用いられている。また、直火加熱方式の欠点で
あるロールピックアップに対しては、特開昭６２＝５４
０３４号公報に、燃焼中間反応生成物を有し且つ遊離酸
素を有しない非平衡領域、所謂未燃火炎を鋼板に衝突さ
せ鋼板を還元しロールピックアップを低減することが提
案されている。Of these, the latter direct-fire heating method has superior heating capacity compared to the indirect heating method, and has the advantage of being able to burn out the cold rolling oil, eliminating the need for cleaning equipment, and is widely used in hot-dip galvanizing lines. It is used in continuous annealing lines for iron and steel plates. In addition, regarding roll pickup, which is a drawback of the direct flame heating method,
No. 034 proposes that a non-equilibrium region containing combustion intermediate reaction products and no free oxygen, a so-called unburned flame, impinges on a steel plate to reduce the steel plate and reduce roll pickup.
しかしながら、本発明者らのテスト結果では、焼鈍工程
前の鋼帯製造工程によっては従来直火炉に比較し、直火
還元を行なった鋼帯はメツキ性において若干劣る場合が
存在することが判明した。However, the inventors' test results revealed that, depending on the steel strip manufacturing process before the annealing process, steel strips subjected to direct fire reduction may be slightly inferior in plating performance compared to conventional direct fire furnaces. .
本発明者らは直火還元した鋼帯の表面状態を詳細に分析
した結果、製造工程により、鋼帯表面のカーボン付着量
が多くこれがメツキ性を大きく阻害していること、また
従来直火炉で表面に付着したカーボンが問題とならない
のは従来直火炉は空気比１以下で燃焼しているにもかか
わらずカーボンにとっては酸化雰囲気であり炉内で焼失
するためで、特開昭６２−５４０３４号公報のような直
火還元法ではこの効果はあまり期待できないことが判明
した。As a result of detailed analysis of the surface condition of the steel strip subjected to direct fire reduction, the present inventors found that due to the manufacturing process, there was a large amount of carbon adhesion on the surface of the steel strip, which greatly inhibited plating properties. The reason why carbon adhering to the surface is not a problem is that although conventional direct-fired furnaces burn at an air ratio of less than 1, it is an oxidizing atmosphere for carbon and is burned away in the furnace. It was found that this effect could not be expected much with the direct flame reduction method as disclosed in the publication.
また、ある種の直火バーナーを用いると直火炉内でもカ
ーボンの発生が著しく、その後の鋼帯の化成処理を甚だ
しく阻害することが知られている。Furthermore, it is known that when certain types of direct-fired burners are used, carbon is generated significantly even in the direct-fired furnace, which seriously impedes the subsequent chemical conversion treatment of the steel strip.
従来この炉内でのカーボン付着を防ぐため、特開昭６０
−７７９３１号公報に示されるように、直火炉入口から
鋼帯温度６００℃〜８００℃となるまで、空気比１．０
以下で燃焼させたバーナーの燃焼ガスの燃焼反応が完了
した領域（いわゆる燃焼排ガス）を鋼帯表面にあてて鋼
帯を加熱し、鋼帯温度が前記温度を越える加熱の後段階
においては、空気比１．０以下で燃焼させたバーナーの
燃焼ガスの、未反応酸素を含まず且つ反応途中の中間イ
オンの存在する領域を鋼板表面に当てて鋼帯を加熱する
方法が提案されている。Conventionally, in order to prevent carbon adhesion inside this furnace,
As shown in Publication No. 77931, the air ratio is 1.0 from the inlet of the direct-fired furnace until the steel strip temperature reaches 600°C to 800°C.
The area where the combustion reaction of the combustion gas of the burner has been completed (so-called combustion exhaust gas) is applied to the steel strip surface to heat the steel strip, and in the post-heating stage where the steel strip temperature exceeds the above temperature, air is heated. A method has been proposed in which a steel strip is heated by applying a region of combustion gas from a burner, which is burned at a ratio of 1.0 or less, which does not contain unreacted oxygen and where intermediate ions are present during the reaction, to the surface of the steel sheet.
しかし、鋼帯の焼鈍ラインでは鋼種による必要加熱温度
、ラインスピード等が大きく変化し、特開昭６０−７７
９３１号公報のように鋼板温度域によって異なる燃焼ガ
ス領域で加熱するよう制御することは極めて困難であり
、また、必要加熱温度が特開昭６０−７７９３１号公報
に示された温度以下であるような鋼種に対してはカーボ
ンの除去ができないという欠点があった。However, in the annealing line for steel strips, the required heating temperature, line speed, etc. vary greatly depending on the steel type.
It is extremely difficult to control the heating in different combustion gas ranges depending on the steel plate temperature range as in Japanese Patent Application Laid-open No. 931, and the required heating temperature is not more than the temperature shown in Japanese Patent Application Laid-Open No. 60-77931. The disadvantage is that carbon cannot be removed from steel types such as steel.
このように、直火還元炉には多くの長所が存在するが、
付着カーボンに対する問題点が残されていた。In this way, direct-fired reduction furnaces have many advantages, but
Problems with adhesion of carbon remained.
本発明は前記従来技術の問題点を有利に解決するために
なされたものであって、たとえば鋼帯の入側から順に、
排ガス吸引ダクト、排ガス予熱帯、直火還元加熱帯、必
要により電気加熱による均熱帯、及び冷却帯を連設した
鋼帯の直火式連続焼鈍装置において、酸素濃度が１０〜
１１００ｐｐの燃焼ガスを鋼帯へ直接吹き付けることに
より酸化膜の還元と、付着カーボンの除去を同時に行う
ことを特徴とする鋼帯の連続焼鈍方法及びその装置を特
徴とする。The present invention has been made to advantageously solve the problems of the prior art. For example, starting from the entrance side of the steel strip,
In a direct-fire continuous annealing device for steel strips, which is equipped with an exhaust gas suction duct, an exhaust gas pre-heating zone, a direct-fire reduction heating zone, a soaking zone by electric heating if necessary, and a cooling zone, the oxygen concentration is 10 to 10.
The present invention is characterized by a continuous annealing method for a steel strip and an apparatus therefor, characterized in that oxidation film is reduced and adhering carbon is removed at the same time by directly spraying 1100 pp of combustion gas onto the steel strip.
以下、本発明の詳細な説明する。The present invention will be explained in detail below.
本発明者らは燃焼ガス加熱による鋼帯上のカーボンの除
去作用について詳細に実験検討した結果、次のような結
論が得られた。即ち、燃焼ガス中の酸素濃度が１０ｐｐ
ｍ以上存在すると、直火還元加熱帯内でもメツキ性に影
響しない程度に前記カーボンを除去することが可能であ
るということである。The present inventors conducted a detailed experimental study on the effect of carbon removal on a steel strip by combustion gas heating, and as a result, the following conclusions were obtained. That is, the oxygen concentration in the combustion gas is 10pp.
If the amount of carbon is greater than m, it is possible to remove the carbon even in the direct fire reduction heating zone to the extent that it does not affect the plating properties.
これを第４図に示す。第４図は燃焼ガス中の酸素濃度（
ｐｐｍ） とカーボン除去能力（本発明法の直火還元加
熱帯における除去能力／従来法の直火加熱帯（！！帯に
直接燃焼ガスを吹付けない）における除去能力）及び還
元能力（ｌＩｌ帯の還元部の直径／バーナー直管部の直
径）との関係を示したもので、前記酸素濃度が１０ｐｐ
ｍ以上になると本発明法のカーボン除去能力は従来法の
約４０％以上になり、メツキ性に対し充分にカーボンを
除去することができるのである。This is shown in FIG. Figure 4 shows the oxygen concentration in the combustion gas (
ppm) and carbon removal ability (removal ability in the direct-fired reduction heating zone of the present invention/removal ability in the conventional direct-fired heating zone (!! without blowing combustion gas directly onto the zone)) and carbon removal ability (removal ability in the direct-fired heating zone of the method of the present invention (!! without blowing combustion gas directly onto the zone)) (diameter of reducing section/diameter of straight pipe section of burner), when the oxygen concentration is 10 pp
m or more, the carbon removal ability of the method of the present invention is about 40% or more of the conventional method, and carbon can be removed sufficiently with respect to plating properties.
一方、鋼帯への還元能力は前記燃焼ガスの酸素濃度が１
０ｐｐｍでバーナータイル直管部の直径の約３倍の鋼帯
部分を還元することができるが、酸素が増加するに従い
還元能力は落ち、１ｏｏ、ｐｐｍを超えると急速に酸化
速度が増大し鋼帯に悪影響を与える。従って、カーボン
除去能力を有するとともに還元能力も十分有する燃焼条
件としては、該燃焼の排ガスの酸素濃度を１０〜１１０
０ｐｐの範囲に制御すればよいことが分かった。On the other hand, the reduction ability to steel strip is determined when the oxygen concentration of the combustion gas is 1.
At 0 ppm, it is possible to reduce a steel strip portion approximately three times the diameter of the straight pipe of the burner tile, but as the oxygen content increases, the reduction ability decreases, and when it exceeds 100 ppm, the oxidation rate rapidly increases and the steel strip adversely affect. Therefore, as a combustion condition that has sufficient carbon removal ability and sufficient reduction ability, the oxygen concentration of the combustion exhaust gas should be 10 to 110.
It was found that it is sufficient to control it within the range of 0 pp.
本発明者らは、この制御を可能ならしめる一方案として
、所定の直管部を有するバーナータイル底部において、
該底部ＩＱＯｃｍあたり５孔以上の２重管式吐出孔を設
け、ノズルく内管）には燃料ガス、外管には空気をバー
ナー中心軸に対し平行に流す構造をもつバーナーを開発
した。そして、前記ノズルと外管の口径比（面積比）を
変化することにより、燃料ガスと空気の相対流速を変化
させ、これにより両者の混合状態を変えて燃焼速度を制
御し、燃焼ガス中の酸素濃度を容易に変えることに成功
した。第５図は２重管バーナーノズルの面積比、すなわ
ち、外管（空気孔）の面積／ノズル（燃料孔）の面積の
値と酸素濃度（ｐｐｍ） との間係を示したもので、
例えば酸素濃度を３０ｐｐｍ必要のときはバーナーノズ
ル面積比を３にすればよい。The present inventors have proposed, as a plan to enable this control, that at the bottom of a burner tile having a predetermined straight pipe section,
We have developed a burner with a structure in which five or more double-pipe discharge holes are provided per IQO cm of the bottom, and fuel gas flows through the nozzle (inner tube) and air flows parallel to the burner center axis through the outer tube. By changing the aperture ratio (area ratio) of the nozzle and the outer tube, the relative flow velocity of the fuel gas and air is changed, thereby changing the mixing state of the two and controlling the combustion speed. We succeeded in easily changing the oxygen concentration. Figure 5 shows the relationship between the area ratio of a double tube burner nozzle, that is, the area of the outer tube (air hole)/the area of the nozzle (fuel hole), and the oxygen concentration (ppm).
For example, if an oxygen concentration of 30 ppm is required, the burner nozzle area ratio may be set to 3.
また、本発明に係るバーナーを用いた直火還元帯の前段
に該バーナーからの排ガスによって鋼帯を予熱する予熱
帯を設置することにより銅板表面の付着カーボンをある
程度除去することが可能となる。Further, by installing a preheating zone for preheating the steel strip with exhaust gas from the burner upstream of the direct fire reduction zone using the burner according to the present invention, it becomes possible to remove a certain amount of carbon deposited on the surface of the copper plate.
さらに、還元力に余裕がある場合、排ガス予熱帯に空気
吹き込みを行うことにより、付着カーボン除去は若干促
進される。Furthermore, if there is sufficient reducing power, the removal of adhering carbon can be slightly accelerated by blowing air into the exhaust gas preparatory zone.
このように直火還元加熱帯前段に排ガス予熱帯を設ける
ことにより、カーボンの除去はより一層完全に行われる
。また当然炉熱効率も向上する。By providing the exhaust gas pre-heating zone before the direct-fired reduction heating zone in this manner, carbon removal can be performed more completely. Naturally, the furnace thermal efficiency also improves.
本発明の連続焼鈍装置は第１図に示すように、排気予熱
帯１と直火還元加熱帯３とを連設し、該加熱帯３で生じ
た熱焼排ガスＧを前記予熱帯１へ送るための排ガス吸引
ダクト２を前記予熱帯１の前方に配置し、かつ前記加熱
帯３の出側に冷却帯７を連設して構成されている。As shown in FIG. 1, the continuous annealing apparatus of the present invention has an exhaust pre-heating zone 1 and a direct-fired reduction heating zone 3 installed in series, and sends the thermal annealing exhaust gas G generated in the heating zone 3 to the pre-heating zone 1. An exhaust gas suction duct 2 is arranged in front of the preheating zone 1, and a cooling zone 7 is connected to the outlet side of the heating zone 3.
前記直火還元加熱帯３にはバーナー５を鋼帯Ｓの進行方
向に沿って多段配列したバーナー列６を鋼帯Ｓの両面に
面して配設しである。前記バーナー５の一実施例を第３
図に示す。In the direct-fired reduction heating zone 3, burner rows 6 in which burners 5 are arranged in multiple stages along the traveling direction of the steel strip S are arranged facing both sides of the steel strip S. A third embodiment of the burner 5
As shown in the figure.
図において、直火還元加熱帯３の壁体１６の適当個所に
バーナータイル部１０を設け、その一端を開放端として
加熱炉内部に接せしめ、他端に底部１１を設ける。該底
部１１にはノズル１９を挿入する外管１２を適当数穿設
する。バーナータイル部１０は直管部１４と必要により
拡径８１５で構成されている。バーナータイル底部１１
の外周に外筒１３が設けられ、該外筒１３内に内筒１７
と、該内筒１７に連結する燃料拡散室１８、該燃料拡散
室１８の壁面に突設したノズル１９が配設されている。In the figure, burner tile portions 10 are provided at appropriate locations on the wall 16 of the direct-fired reduction heating zone 3, one end of which is open and in contact with the inside of the heating furnace, and the other end is provided with a bottom portion 11. A suitable number of outer tubes 12 into which nozzles 19 are inserted are bored in the bottom 11. The burner tile section 10 is composed of a straight pipe section 14 and an enlarged diameter 815 if necessary. Burner tile bottom 11
An outer cylinder 13 is provided on the outer periphery of the
A fuel diffusion chamber 18 connected to the inner cylinder 17 and a nozzle 19 projecting from the wall of the fuel diffusion chamber 18 are provided.
該ノズル１９は前述の如く、バーナータイル底部の外管
１２内にその先端が挿入配置され、該ノズル１９の外側
面と外管１２との間に間隙部を設けるようにする。この
ようにして、バーナータイル底部１１に２重管式吐出孔
２０を構成する。As described above, the tip of the nozzle 19 is inserted into the outer tube 12 at the bottom of the burner tile, and a gap is provided between the outer surface of the nozzle 19 and the outer tube 12. In this way, the double-pipe discharge hole 20 is formed in the bottom portion 11 of the burner tile.
このような構造よりなるバーナー５の外筒１３に空気を
、又、内筒１７に燃料ガスを流すと、２重管式吐出孔２
０より両者がバーナー中心軸に対して平行に層状をなし
て流れ、バーナータイル直管部内で均一に十分混合する
とともに空気比を０，７〜０．９に調整し、バーナーノ
ズル面積比を制御することにより燃焼排ガス中の酸素濃
度が１０〜１１００ｐｐに調整された高温の燃焼ガスが
発生し、バーナータイル底部１１より５０〜３００ｍｍ
離れた移動中の鋼帯表面に前記高温燃焼ガスが吹付けら
れる。When air flows into the outer cylinder 13 of the burner 5 having such a structure, and fuel gas flows into the inner cylinder 17, the double-pipe discharge hole 2
From 0, both flow in a layered manner parallel to the burner center axis, and are uniformly and thoroughly mixed within the straight pipe section of the burner tile, and the air ratio is adjusted to 0.7 to 0.9 to control the burner nozzle area ratio. As a result, high-temperature combustion gas is generated in which the oxygen concentration in the combustion exhaust gas is adjusted to 10 to 1100 pp, and the temperature is 50 to 300 mm from the burner tile bottom 11.
The hot combustion gas is blown onto the surface of the moving steel strip at a distance.
このようにして鋼帯Ｓが直火還元加熱帯３で加熱還元さ
れるが、燃焼によって生じた排ガスＧは連続焼鈍炉の入
側に設けた排ガス吸引ダクト２によって吸引され、鋼帯
の進行方向に逆向して流れる。本発明ではか＼る排ガス
により排ガス予熱帯１を構成して鋼帯を予熱するが、更
に燃焼排ガス中の残留微量酸素によって鋼帯に付着した
カーボンを一部燃焼せしめる。燃焼排ガスは上述の如（
弱酸化性なため鋼帯表面に若干酸化膜が生成するが、該
酸化膜は次工程の直火還元加熱帯の直火バーナーで還元
されまたこの時、同時に鋼帯に付着したカーボンも完全
に除去される。In this way, the steel strip S is heated and reduced in the direct-fired reduction heating zone 3, but the exhaust gas G generated by the combustion is sucked by the exhaust gas suction duct 2 installed on the entrance side of the continuous annealing furnace, and is flows in the opposite direction. In the present invention, the exhaust gas preheats the steel strip by forming the exhaust gas preheating zone 1, and further burns a portion of the carbon attached to the steel strip using the trace amount of oxygen remaining in the combustion exhaust gas. The combustion exhaust gas is as described above (
Due to its weak oxidizing properties, a slight oxide film is formed on the surface of the steel strip, but this oxide film is reduced in the direct fire burner of the direct fire reduction heating zone in the next step, and at the same time, the carbon attached to the steel strip is completely removed. removed.
一方、溶融メツキラインにおいては直火還元加熱帯で加
熱還元された鋼帯Ｓが熱処理不要な鋼種である場合、直
接冷却帯７へ送られ、メツキ浴温度程度上冷却される。On the other hand, in the melt plating line, if the steel strip S heated and reduced in the direct flame reduction heating zone is of a steel type that does not require heat treatment, it is directly sent to the cooling zone 7 and cooled to about the temperature of the plating bath.
上記鋼種が均熱処理を必要とする場合は第２図に示すよ
うに直火還元加熱帯３と冷却帯７の間に均熱帯９を設け
る。該均熱帯９は前工程の加熱帯３で鋼帯が還元処理さ
れているのでラジアントチューブを設けた還元雰囲気炉
でなくてよく、安価な加熱手段、例えば電気加熱装置を
設けることができる。If the steel type described above requires soaking treatment, a soaking zone 9 is provided between the direct-fired reduction heating zone 3 and the cooling zone 7, as shown in FIG. Since the steel strip is subjected to reduction treatment in the heating zone 3 in the previous step, the soaking zone 9 does not need to be a reducing atmosphere furnace equipped with a radiant tube, and can be provided with an inexpensive heating means such as an electric heating device.
上記の如く、排ガス予熱帯１では若干酸化膜が鋼帯表面
に生成するが、鋼帯の温度が低いため排ガス予熱帯１と
直火還元加熱帯３との間のハースロール８Ｂにはピック
アップが生じない。また直火還元加熱帯３と均熱帯９又
冷却帯７との間のハースロール８０〜８Ｇ等も、直火還
元加熱帯３で鋼帯が直火還元加熱処理されるので鋼帯表
面の酸化膜が除去されるためピックアップが生じない。As mentioned above, a slight oxide film is formed on the surface of the steel strip in the exhaust gas pre-heating zone 1, but since the temperature of the steel strip is low, there is no pickup in the hearth roll 8B between the exhaust gas pre-heating zone 1 and the direct-fire reduction heating zone 3. Does not occur. In addition, the hearth rolls 80 to 8G, etc. between the direct-fired reduction heating zone 3 and the soaking zone 9 or the cooling zone 7 are also subjected to direct-fired reduction heating treatment in the direct-fired reduction heating zone 3, so the surface of the steel strip is oxidized. Pick-up does not occur because the film is removed.
次に第１図の連続焼鈍装置で鋼帯を処理した結果につい
て説明する。Next, the results of processing a steel strip using the continuous annealing apparatus shown in FIG. 1 will be explained.
直火還元加熱炉のバーナーに燃料ガスとしてコークス炉
ガスを燃焼料５０．０００Ｋｃａｌ／ ｈ使用し、空気
とともに゛２重管式吐出孔より層状に流し、バーナータ
イル直管部内で空気比を０．８に調整し、均一混合して
燃焼せしｔた。50.000 Kcal/h of coke oven gas is used as a fuel gas in the burner of a direct-fired reduction heating furnace, and it is flowed in a layered manner along with air from the double pipe discharge hole, and the air ratio is set to 0. 8, mixed uniformly, and burned.
上記バーナーはバーナータイル底部に２５個の２重管を
設けたバーナ一部と、バーナータイル直管部直径８５闘
、長さを１００ｍｍとしたバーナータイル部で構成した
。そして、ノズルを外管内に移動して両者の面積比を３
に調整し、燃焼排ガス中の酸素濃度を３０ｐｐｍにした
。か−る燃焼排ガスを２０ｍの排ガス予熱帯に吸引せし
め、その雰囲気温度を１０００℃とした。The burner was composed of a burner part with 25 double pipes provided at the bottom of the burner tile, and a burner tile part with a straight pipe part of the burner tile having a diameter of 85 mm and a length of 100 mm. Then, move the nozzle into the outer tube to increase the area ratio of the two to 3.
The oxygen concentration in the combustion exhaust gas was adjusted to 30 ppm. The combustion exhaust gas was drawn into a 20 m long exhaust gas pre-heating zone, and the ambient temperature was set at 1000°C.
この結果、鋼帯は排ガス予熱帯で４００℃に予熱され、
かつ、鋼帯表面のカーボン（５■／ｍ゛）はその３０％
が燃焼除去された。次いで鋼帯は１０ｍの直火還元加熱
帯に送られ、該加熱帯で８００℃に加熱されるとともに
残りのカーボン及び酸化膜も全て除去された。次に鋼帯
は冷却帯へ送られ、４５０℃に冷却された。か＼る鋼帯
にメツキ処理を施したところ極めて良好なメツキ性を示
した。As a result, the steel strip is preheated to 400℃ in the exhaust gas preheating zone,
And the carbon on the steel strip surface (5■/m゛) is 30% of that.
was removed by combustion. The steel strip was then sent to a 10 m direct-fire reduction heating zone where it was heated to 800° C. and all remaining carbon and oxide films were removed. The steel strip was then sent to a cooling zone and cooled to 450°C. When the steel strip was plated, it showed extremely good plating properties.
このように本発明の鋼帯熱処理方法及び装置によれば鋼
帯に付着したカーボンは予熱帯及び直火還元加熱帯で燃
焼され、かつ、予熱された鋼帯は直火還元加熱帯で直接
加熱還元されるので、後工程に還元炉やラジアントチュ
ーブ付き均熱炉等を必要とせずに鋼帯表面を清浄化する
ことが可能となった。As described above, according to the steel strip heat treatment method and apparatus of the present invention, carbon adhering to the steel strip is burned in the preheating zone and the direct flame reduction heating zone, and the preheated steel strip is directly heated in the direct flame reduction heating zone. Since it is reduced, it is now possible to clean the surface of the steel strip without requiring a reduction furnace or a soaking furnace with a radiant tube in the subsequent process.
本発明は詳述したように、直火加熱還元炉に設けた本発
明のバーナーによって鋼帯表面を還元処理するとともに
鋼帯に付着したカーボンを燃焼させることができ、これ
により連続焼鈍炉の加熱清浄化効果を一層発揮すること
ができる。As described in detail, the present invention can reduce the surface of the steel strip and burn carbon attached to the steel strip using the burner of the present invention installed in the direct-fired heating reduction furnace, thereby heating the continuous annealing furnace. The cleaning effect can be further demonstrated.
第１図は本発明の連続焼鈍炉の一例を示す概略断面正面
図、第２図は本発明の他の実施例を示す概略断面正面図
、第３図は本発明のバーナー構造を示し、同図（ａ）は
断面正面図、同図（ｂ）はその側面図、第４図は燃焼排
ガス中酸素濃度とカーボン除去能力及び還元能力との関
係を示す図、第５図はバーナーノズル面積比と酸素濃度
の関係を示す図である。
１・・・排ガス予熱帯、 ２・・・排ガス吸引ダクト、
３・・・直火還元加熱帯、５・・・バーナー６・・・バ
ーナー列、 ７・・・冷却帯、８Ａ〜８Ｇ・・・ハー
スロール、
９・・・均熱帯、 １０・・・バーナータイル部
、１１・・・バーナータイル底部、
１２・・・外管、 １３・・・外筒、１４・・
・バーナータイル直管部、
１５・・・バーナータイル拡径部、
１６・・・直火還元加熱炉壁体、
１７・・・内筒、 １８・・・燃料拡散室、１
９・・・バーナーノズル、２０・・・２重管式吐出孔、
Ｓ・・・鋼帯、 Ｇ・・・燃焼排ガス。FIG. 1 is a schematic cross-sectional front view showing an example of the continuous annealing furnace of the present invention, FIG. 2 is a schematic cross-sectional front view showing another embodiment of the present invention, and FIG. Figure (a) is a cross-sectional front view, Figure (b) is a side view, Figure 4 is a diagram showing the relationship between oxygen concentration in combustion exhaust gas, carbon removal ability, and reduction ability, and Figure 5 is a burner nozzle area ratio. It is a figure showing the relationship between and oxygen concentration. 1... Exhaust gas preparatory zone, 2... Exhaust gas suction duct,
3... Direct fire reduction heating zone, 5... Burner 6... Burner row, 7... Cooling zone, 8A to 8G... Hearth roll, 9... Soaking zone, 10... Burner Tile part, 11... Burner tile bottom, 12... Outer pipe, 13... Outer cylinder, 14...
- Burner tile straight pipe part, 15... Burner tile enlarged diameter part, 16... Direct fire reduction heating furnace wall body, 17... Inner cylinder, 18... Fuel diffusion chamber, 1
9... Burner nozzle, 20... Double pipe discharge hole,
S... Steel strip, G... Combustion exhaust gas.
Claims (1)
、該直火還元加熱帯では、燃焼ガス中の酸素濃度を１０
〜１００ｐｐｍとして鋼帯の直火還元加熱を行い加熱後
の排ガスを前記排ガス予熱帯へ導入して鋼帯の予熱を行
うことを特徴とする鋼帯の直火式連続焼鈍方法。 ２、鋼帯の入側から順次、排ガス吸引ダクト、弱酸性雰
囲気を有する排ガス予熱帯、直火還元加熱帯、電気加熱
による均熱帯及び冷却帯を連設したことを特徴とする鋼
帯の直火式連続焼鈍装置。 ３、前記直火還元加熱帯において、直管部を有するバー
ナータイル底部に小径の２重管式吐出孔を前記バーナー
タイル底部面積１００ｃｍ＾２あたり５個以上開口して
形成したバーナーを多数配設してバーナー列を構成した
請求項２記載の焼鈍装置。[Claims] 1. An exhaust gas pre-heating zone is provided on the inlet side and a direct flame reduction heating zone is provided on the outlet side, and in the direct flame reduction heating zone, the oxygen concentration in the combustion gas is reduced to 10.
A direct-fire continuous annealing method for a steel strip, characterized in that the steel strip is subjected to direct-fire reductive heating at a concentration of 100 ppm to 100 ppm, and the heated exhaust gas is introduced into the exhaust gas pre-heating zone to preheat the steel strip. 2. A straight steel strip characterized by having an exhaust gas suction duct, an exhaust gas pre-heating zone with a slightly acidic atmosphere, a direct fire reduction heating zone, a soaking zone by electric heating, and a cooling zone successively installed from the entrance side of the steel strip. Fire type continuous annealing equipment. 3. In the direct-fired reduction heating zone, a large number of burners are arranged in which five or more small-diameter double-pipe discharge holes are opened per 100 cm^2 of the bottom area of the burner tile at the bottom of the burner tile having a straight pipe part. 3. The annealing apparatus according to claim 2, wherein the burner row is configured by:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2180547A JPH0781167B2 (en) | 1990-07-10 | 1990-07-10 | Direct-fire continuous annealing method and apparatus for steel strip |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2180547A JPH0781167B2 (en) | 1990-07-10 | 1990-07-10 | Direct-fire continuous annealing method and apparatus for steel strip |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0472023A true JPH0472023A (en) | 1992-03-06 |
| JPH0781167B2 JPH0781167B2 (en) | 1995-08-30 |
Family
ID=16085188
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2180547A Expired - Lifetime JPH0781167B2 (en) | 1990-07-10 | 1990-07-10 | Direct-fire continuous annealing method and apparatus for steel strip |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0781167B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20180125518A (en) * | 2016-04-15 | 2018-11-23 | 안드리츠 테크날러지 앤드 에셋 매니지먼트 게엠베하 | Furnace Furnace and Heat Treatment Method for Heat Treatment of Metal Strips |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5591942A (en) * | 1978-12-29 | 1980-07-11 | Nippon Steel Corp | Continuous annealing equipment for cold rolled steel strip |
| JPS6056760U (en) * | 1983-09-24 | 1985-04-20 | 日本鋼管株式会社 | Vertical direct-fired continuous annealing furnace |
| JPS6077931A (en) * | 1983-10-05 | 1985-05-02 | Nippon Kokan Kk <Nkk> | Oxygen free heating method of steel strip |
| JPS6254031A (en) * | 1985-08-31 | 1987-03-09 | Nippon Kokan Kk <Nkk> | Direct firing heating furnace of continuous annealing installation for steel strip |
| JPS6254035A (en) * | 1985-08-31 | 1987-03-09 | Nippon Kokan Kk <Nkk> | Continuous heat treatment of steel strip |
| JPS6254034A (en) * | 1985-08-31 | 1987-03-09 | Nippon Kokan Kk <Nkk> | Continuous annealing installation for steel strip |
-
1990
- 1990-07-10 JP JP2180547A patent/JPH0781167B2/en not_active Expired - Lifetime
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5591942A (en) * | 1978-12-29 | 1980-07-11 | Nippon Steel Corp | Continuous annealing equipment for cold rolled steel strip |
| JPS6056760U (en) * | 1983-09-24 | 1985-04-20 | 日本鋼管株式会社 | Vertical direct-fired continuous annealing furnace |
| JPS6077931A (en) * | 1983-10-05 | 1985-05-02 | Nippon Kokan Kk <Nkk> | Oxygen free heating method of steel strip |
| JPS6254031A (en) * | 1985-08-31 | 1987-03-09 | Nippon Kokan Kk <Nkk> | Direct firing heating furnace of continuous annealing installation for steel strip |
| JPS6254035A (en) * | 1985-08-31 | 1987-03-09 | Nippon Kokan Kk <Nkk> | Continuous heat treatment of steel strip |
| JPS6254034A (en) * | 1985-08-31 | 1987-03-09 | Nippon Kokan Kk <Nkk> | Continuous annealing installation for steel strip |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20180125518A (en) * | 2016-04-15 | 2018-11-23 | 안드리츠 테크날러지 앤드 에셋 매니지먼트 게엠베하 | Furnace Furnace and Heat Treatment Method for Heat Treatment of Metal Strips |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0781167B2 (en) | 1995-08-30 |
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