JP2005060738A - Method and device for sealing atmospheric gas - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and a device for sealing atmospheric gas with which the capacity in a gas refining apparatus can be compacted without mixing with atmospheric gas in the adjoined different atmosphere, and rolling reduction force is not developed to a steel strip passed through sealing roll parts and slipped flaw and bit flaw with the sealing rolls are not developed. <P>SOLUTION: In the method for sealing the atmospheric gas at the inlet and/or the outlet of a heat treatment furnace for heat-treating the steel strip by sealing inert gas, the method and the device for sealing the atmospheric gas, are as the followings, that is, a plurality of sets of one pair of the sealing rolls interposing the steel strip, are arranged, and both sealing rolls as one pair, are set by arranging the gap having more than the maximum thickness of this steel strip by shifting in the running direction of the steel strip and the atmospheric gas is exhausted from the gap of the plurality of sets of the sealing rolls. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００１２】
（４）前記１組目のシールロール側から雰囲気ガスを排出する雰囲気ガス排出管を設置し、該雰囲気ガス排気管をミキサに連結してＮ_２ガスと混合して熱処理炉に連結している入側および出側の炉体に吹き込むことを特徴とする（１）乃至（３）に記載の雰囲気ガスのシール方法。
（５）不活性ガスを封入して鋼帯を熱処理する熱処理炉の入口および／または出口における雰囲気ガスのシール装置であって、
前記鋼帯を挟む１対のシールロールを複数組配設し、
該１対をなすシールロール同士を前記鋼帯の走行方向にずらして、該鋼帯の最大板厚以上の隙間を開けて設置したことを特徴とする雰囲気ガスのシール方装置。
（６）前記１対のシールロールは、該シールロールの軸中心を結んだ軸線とシールロールの外形が接する点のロール間距離Ｌが下記▲３▼式を満足することを特徴とする（５）に記載の雰囲気ガスシール装置。

【００１３】
【発明の実施の形態】
本発明の実施形態について、図１乃至図５を用いて詳細に説明する。
図１および図２は、本発明の雰囲気ガスのシール装置を設置した熱処理炉を例示する図である。
図３は、本発明の雰囲気ガスのシール装置におけるシール部を例示する図である。
図４は、本発明を採用した場合の炉内圧力分布を示す図である。
図５は、シールロールの離間寸法とリーク量の関係を示す図である。
図１において、本発明のシール方法およびシール装置を連続焼鈍炉へ採用した場合の実施例を示す。
連続焼鈍炉は加熱帯１、均熱帯２、徐冷帯３、急冷帯４、過時効帯５、最終冷却帯６で構成されている。鋼帯９は加熱帯１にて所定の温度に加熱され、均熱帯２を経て、徐冷帯３、急冷帯４、処理材料に応じて過時効帯５を通過し、最終冷却帯により所定の温度まで冷却され、炉外に搬送される。加熱帯１と均熱帯２との間に本発明のシール装置を採用している。
【００１４】
加熱帯１では、鋼帯９の加熱装置として輻射加熱方式や直火バーナによる加熱装置が採用されている。噴射加熱の場合、炉内の雰囲気ガスは、均熱帯２に使用する雰囲気ガスと変わらないため、加熱帯１と均熱帯２との間にシール装置を設置する必要はないが、直火バーナにより鋼帯９を加熱する場合、加熱帯１の雰囲気ガスは弱酸化雰囲気となるため、加熱帯１に連結される均熱帯２とはシールが必要になる。図１では加熱帯１と均熱帯２を連結するスロート部にシールロール方式のシール装置を配置した。シールロールは鋼帯９を挟んで上下に１対とし、鋼帯９の走行方向に間隔をあけて２組配置している。そしてこの間から雰囲気ガスを排気する雰囲気ガス排気管１３を連結している。
【００１５】
シールロールは鋼帯の上下に鋼帯を挟んで鋼帯の走行方向にずらして、シールロールの面はシールロールを通過する鋼帯の最大板厚の隙間をあけて配置し、複数組（本実施形態では２組）のシールロールの間から雰囲気ガスを排気するようにする。このシール装置により隣接する炉体の雰囲気ガスがそれぞれの炉体の侵入することはない。また、図３に示すように上下に配置するシールロールのうち鋼帯９の上面に配置するシールロール１０−２は鋼帯９の下面に配置するシールロール１０−１よりずらして配置している。これにより鋼帯９の上面に位置するシールロール１０−２は鋼帯９に接触させるのみで、上下に配置する場合には板厚の変更等により鋼帯９を挟持することになるため、シールロール１０−１．１０−２のスリップや異物の噛みこみによりより鋼帯９に疵が発生することが懸念され上部に配置するシールロール１０−２は板厚の変化分にプラスして若干の余裕をみて隙間を開けて配置することになる。この状態でも本発明のシール方法で問題はないが、さらにシール性を向上させるため上下シールロールのうち上部シールロール１０−２を鋼帯９の走行方向にずらして配置している。上部シールロール１０−２をずらすことで鋼帯９の板厚が変化しても鋼帯９をシールロールで挟持しないので、鋼帯９へのシールロールにより起因する疵は発生しない。
【００１６】
また、図１では急冷帯４に入口および出口に本発明のシール装置１０を配置している。急冷帯４の冷却方法としてガスジェット循環方式の冷却装置を採用している。そして、冷却能力を高めるため、雰囲気ガスとして水素濃度５０％以上の冷媒を使用して鋼帯の急速冷却を行っている。この場合急冷帯４の前後に連結する徐冷帯３および過時効帯５の雰囲気とは異種雰囲気となるため急冷帯４の入口および出口に本発明のシール装置１０を配置している。具体例を図２に示す。
【００１７】
図２において徐冷帯３を通過した鋼帯９は徐冷帯３出側のトップロール７を介して急冷帯４の入口のトップロール７により急冷帯４内に搬送される。搬送された鋼帯９は急冷帯４内に配置した冷却装置１２により鋼帯に冷媒を吹き付けて所定の温度まで急速冷却し、急冷帯４出口に配置したボトムロール８を介して次のチャンバへ搬送される。図２では過時効帯５を連結しているが、処理形態によっては最終冷却帯の場合もある。
徐冷帯３の出側のトップロール７と急冷帯４入側のトップロール７との間はスロート１１により連結され、このスロート１１内に鋼帯９を搬送させて急冷帯４に搬送する。このスロート１１内に鋼帯９を挟んで上下にシールロール１０−１．１０−２で１対のシールロールを間隔をあけて２組配置している。シールロール１０−１．１０−２は鋼帯の上下面に対向してシールロール面が接触するように配置しても良いが、図３に示すように鋼帯９の下部に位置するシールロール１０−１に対して鋼帯９の走行方向にずらして配置してもよい。図３では鋼帯９の走行方向に上部のシールロール１０−２をずらして配置した１対のシールロールを２対配置しいている。そしてこの対のシールロールの間から雰囲気ガスを排出する雰囲気ガス排出管１３を設置している。急冷帯４の雰囲気ガスは水素濃度が５０％以上に雰囲気ガスが使用され、徐冷帯３では水素濃度が５〜１０％でその残りの窒素ガスを混合した雰囲気ガスが使用されている。雰囲気ガス排出管１３により吸引された雰囲気ガスはガス精製装置で水素ガスと窒素ガスに分離され、水素ガスは急冷帯４に戻されて循環使用される。一方、急冷帯４の出側にも同様にシール装置１０を配置し、前記と同様に使用される。
【００１８】
また、シール部の炉内圧力分布は図４に実線で示すように徐冷帯３と急冷帯４の間にシール装置１０を設置した場合、徐冷帯３側の圧力Ａ＜シールロール間の圧力Ｂ＜急冷帯側の圧力Ｃ・・・▲１▼となるように調整してシールロール間から雰囲気ガスを排出する。例えば、徐冷帯３側の圧力を１ｍｍＡｑ、シールロール間の圧力を１．５ｍｍＡｑ、急冷帯４側の圧力を２ｍｍＡｑに調整することで、徐冷帯４側の雰囲気ガスを吸引することなく雰囲気ガスを排出することができる。このように圧力を調整して雰囲気ガスを排出することで、高水素濃度の雰囲気ガスを吸引してガス精製装置１６に供給できるので、ガス精製装置１６の容量をコンパクトにすることができる。また、徐冷帯３側の徐冷帯３とシール装置１０の間にはシールロールからリークする雰囲気ガスを排出する雰囲気ガス排出管１８を設置している。
この雰囲気ガス排出管１８により徐冷帯３側にリークする雰囲気ガスを吸引して、雰囲気ガス排出管１８に連結したミキサ１９に供給して窒素ガスと混合して濃度を調整し、徐冷帯３に供給して徐冷帯３の雰囲気ガスとして再使用している。
【００１９】
また、急冷帯４の出側についても同様に、急冷帯４出側と過時効帯５入側を連結し、このスロート内に急冷帯４側ボトムロールを介して過時効帯５入口のボトムロールにより鋼帯９を搬送する。そして、鋼帯９の上下面にシールロール１０−１．１０−２を鋼帯９を挟んで配置した１対をなすシールロールを鋼帯の走行方向に間隔をあけて２対配置している。そしてこのシールロールの間から雰囲気ガスを排出する雰囲気ガス排出管１３を設け、雰囲気ガスを吸引する。吸引された雰囲気ガスは雰囲気ガス排出管１３に連結されたガス精製装置１６により分離され、分離された水素ガスは急冷帯４に導入されて冷媒として再使用される。
【００２０】
また、急冷帯４の出側で過時効帯５の入側には、シール装置１０から過時効帯５側にリーク雰囲気ガスを排出する雰囲気ガス排気管１８を設けている。リークする雰囲気ガスを雰囲気ガス排出管１８により吸引して、雰囲気ガス排出管１８に連結したミキサ１９に導入して雰囲気ガスの濃度を調整して過時効帯５に導入する。
急冷帯４と過時効帯５の間に設置したシール装置の圧力バランスは、図４の点線で示すように、急冷帯４出側の圧力Ａ＞シールロール間の圧力Ｂ＞過時効帯５入側の圧力Ｃ・・・▲２▼とし、急冷帯４出側の圧力Ｃを２ｍｍＡｑ、シールロール間の圧力Ｂを１．５ｍｍＡｑ、過時効帯５入側の圧力Ａを１ｍｍＡｑに調整する。このように調整することで過時効帯５側の雰囲気ガスが急冷帯４に侵入することはない。
また、このように圧力を調整することで、シールロール間から吸引する雰囲気ガスは急冷帯４側の高水素濃度の雰囲気ガスを吸引してガス精製装置１６に供給できるので、ガス精製装置１６の容量をコンパクトにすることができる。
【００２１】
図３は本発明のシール装置の具体例を示す。
図３において、鋼帯９が矢印の方向に走行している場合、鋼帯９の下部に鋼帯９の下面にシールロール１０−１の表面が接触するように配置する。そして、そのシールロール１０−１に対応するシールロール１０−２を鋼帯９の上面にシールロール１０−２の表面が接触するように配置する。鋼帯９上面に配置したシールロール１０−２は鋼帯の走行方向に鋼帯の下部に配置したシールロール１０−１より離間して配置している。
この離間寸法はｔ_ｍａｘ≦Ｌ≦５０（ｍｍ）・・・▲３▼の範囲で設定する。
ここで、ｔ_ｍａｘは処理される材料の最大板厚（ｍｍ）でＬはロール間距離（ｍｍ）である。この範囲に設定することで、シールロールによる接触疵や異物の噛み込みにより疵の発生は防止できる。つまり、シールロール１０−１および１０−２を鋼帯９を挟んで上下に対向させて配置した場合、上下シールロール間の隙間は通過する板厚の最大厚みの隙間に設置する。しかし最大板厚の鋼帯９が上下シールロール間を通過する際、上下シールロールに挟まれることになり、鋼帯へのすり疵や異物噛み込み疵が発生しやすくなる。そこで図３に示すように下部シールロール１０−１より鋼帯の走行方向にシールロールを通過する最大板厚を超える隙間だけずらすことで、上下シールロールによる現象が生じることなく通過する鋼帯への疵も防止できる。また、上部シールロール１０−２の鋼帯の走行方向への離間距離は５０ｍｍを超えると図５に示すようにシール効果が悪化するので５０ｍｍ以下とすることが必要である。
【００２２】
【発明の効果】
以上のように、１対のシールロールを２対配置して、シールロール間から雰囲気ガスを排気し、循環して使用するようにしたので、隣接する異種雰囲気の雰囲気ガスが混合することがない。また、炉圧を調節して排気するので、ガス精製装置の容量もコンパクトにできる。
また、シールロールを鋼帯の走行方向に離間して設置しているので、シールロール部を通過する鋼帯には圧下力が発生せず、シールロールによりスリップ疵や噛み込み傷が発生しないなど、産業上有用な著しい効果を奏する。
【図面の簡単な説明】
【図１】本発明の雰囲気ガスのシール装置を設置した熱処理炉を例示する図である。
【図２】本発明の雰囲気ガスのシール装置を設置した熱処理炉を例示する図である。
【図３】本発明の雰囲気ガスのシール装置におけるシール部を例示する図である。
【図４】本発明を採用した場合の炉内圧力分布を示す図である。
【図５】シールロールの離間寸法とリーク量の関係を示す図である。
【符号の簡単な説明】
１・・・加熱帯、２・・・均熱帯、３・・・徐冷帯、４・・・急冷帯、
５・・・過時効帯、６・・・最終冷却帯、７・・・トップロール、
８・・・ボトムロール、９・・・鋼帯、１０・・・シール装置、
１０−１・・・シールロール、１０−２・・・シールロール、
１０−３・・・シール板、１１・・・スロート、１２・・・冷却装置、
１３・・・雰囲気ガス排気管、１４・・・オリフィス、１５・・・流量調整弁、１６・・・ガス精製装置、１７・・・屋外排気管、
１８・・・雰囲気ガス排気管、１９・・・ミキサ、２０・・・Ｎ_２ガス供給管、２１・・・ミックスガス導入管[0001]
[Technical field to which the invention belongs]
The present invention relates to a method and apparatus for sealing an atmospheric gas used in a heat treatment furnace.
[0002]
[Prior art]
Steel strip heat treatment furnaces, such as continuous annealing furnaces, are passed through the steel strip in the order of the above configuration in the furnace body composed of heating zone, soaking zone, slow cooling zone, quenching zone, overaging zone, cooling zone, etc. The heat treatment is performed in a predetermined heat pattern. During the heat treatment, if the surface of the steel strip is oxidized, the appearance of the product is impaired. Therefore, in an ordinary heat treatment furnace, an inert gas such as HN gas containing hydrogen gas and nitrogen gas containing hydrogen as an atmospheric gas is generally used. Used. In the above configuration, the heating zone employs a direct flame heating method or an induction heating method that heats as fast as possible in order to make the equipment compact.
In addition, as a rapid cooling technique in the quenching zone, a circulating gas jet cooling method in which the atmosphere gas is cooled with a heat exchanger, the space between the cooled atmospheres is sprayed on a steel strip, and the sprayed atmosphere gas is cooled with a heat exchanger, There are a roll cooling method in which a steel strip is pressed against a cooling roll and cooling, and a mistake and a cooling method in which water and gas are mixed and sprayed onto the steel strip. Among these, the gas jet cooling method is widely adopted in terms of the stability of the steel strip shape and the equipment cost.
[0003]
However, the gas jet cooling method has a drawback that the cooling rate is low, and in order to compensate for this disadvantage, HN gas having a high hydrogen concentration and a high cooling capacity is used in the quenching zone.
Regarding this technique, for example, in Japanese Patent Application Laid-Open No. 09-235626, as a cooling gas to be sprayed on a quenched steel strip, a hydrogen concentration is 30 to 60%, a spraying gas temperature is 30 to 150 ° C., and a spraying speed is 100 to 150 m / A method of increasing the cooling rate of the steel strip by setting the second is disclosed.
[0004]
This makes it possible to increase the hydrogen concentration and secure the cooling rate. However, a problem with the heat treatment with a gas having a high hydrogen concentration is a method for sealing a high-concentration hydrogen gas. Japanese Patent Laid-Open No. 9-235626 also outlines the gas seal, but no specific description is found.
[0005]
Thus, in the heating zone, soaking zone, slow cooling zone, quenching zone, overaging zone, and final cooling zone constituting the heat treatment, the components of the atmospheric gas introduced into each furnace body are different. Sealing devices are installed at the inlet and the outlet.
As for the gas seal device, for example, Japanese Patent Laid-Open No. 06-346155 includes at least two rows of seal rolls that are in contact with the upper and lower surfaces of the strip at intervals in the running direction of the strip. It is possible to supply a gas for sealing toward the upper and lower surfaces of the strip, and nozzles for jetting gas at high speed in the same direction as the strip traveling direction are provided above and below the pass line, and these nozzles and the seal roll A sealing device is disclosed in which the above is a throat for an ejector flow path.
[0006]
Moreover, as a device for preventing the quenching zone from entering the cooling gas hearth roll chamber, Japanese Patent Application Laid-Open No. 09-95741 discloses a seal roll for preventing the injected cooling gas from flowing out to the hearth roll side, and these In a cooling zone of a continuous annealing furnace consisting of a furnace body surrounding the whole, the above-mentioned seal rolls are arranged in a staggered manner up and down so that only one side is in contact with both sides of the steel group facing the nozzle group side. It is a cooling zone for a continuous annealing furnace. Moreover, the cooling zone of the continuous annealing furnace in which the seal roll satisfies the relationship of the following formula is disclosed.
Formula: L / (D−d) ≧ 3
[0007]
[Patent Document 1] Japanese Patent Application Laid-Open No. 09-235626 [Patent Document 2] Japanese Patent Application Laid-Open No. 06-346155 [Patent Document 3] Japanese Patent Application Laid-Open No. 09-95741
[Problems to be solved by the invention]
In the technique disclosed in Japanese Patent Laid-Open No. 09-235626, a gas seal between a furnace body that performs a quenching process and an adjacent furnace body is performed to prevent explosion, and a non-contact type sealing device is disclosed in a steel strip. Has been. When different atmosphere gases are blown from the chambers on both sides toward the steel strip and the atmosphere gas is blown onto the steel strip from the center chamber and sealed, the seal gas blown from both sides enters the furnace body and the furnace pressure Can be expected to rise. When the furnace pressure rises, a leak from another seal portion of the furnace body occurs and is released outside the furnace body, which poses a safety problem. Further, in order to prevent the furnace pressure, a blower for sucking the seal gas discharged from the both-side chambers is required for each, which greatly increases the equipment cost and increases the equipment.
[0009]
In addition, two or more rows of seal rolls are arranged, gas is supplied between the seal rolls to form a gas seal layer, and nozzles for injecting a high-speed gas flow are provided above and below the pass line on the downstream side of the gas seal layer, In the sealing device that draws out the gas between the seal rolls by the ejector effect generated by the gas injection, the gas can be prevented from flowing into the furnace body on one side of the adjacent furnace body, but the gas on the other side can be prevented. It flows out to the furnace body and the furnace pressure of the other furnace body rises. For this reason, the furnace pressure balance of the adjacent furnace bodies is broken, and an ejection flow velocity corresponding to the furnace pressure on the other side is required. For this reason, it is necessary to blow out the high-speed jet gas at a higher speed, which repeatedly increases the other furnace pressure. Moreover, the atmospheric gas from one side furnace body will also flow out.
[0010]
Moreover, in order to prevent the gas injected in the gas injection cooling zone from flowing into the roll chamber, the cooling device in which the seal roll is arranged above the roll chamber prevents the gas injected from the plenum chamber from flowing into the roll chamber. Therefore, a certain distance is provided, and the seal rolls are arranged in a staggered manner between the distances, so that a space between the plenum chamber and the roll chamber is required, and the equipment for the cooling zone is increased. In addition, even if a space is provided between the plenum chamber and the roll chamber, gas leakage from the roll contact surface can be prevented, but the gas that enters and exits the back of the roll stays in the space, and as a result, the gas that stays in this space is It entered the roll chamber through the slit-shaped through-hole through which the steel strip passed, and could not be sealed.
Therefore, the present invention solves the above-mentioned problems of the prior art, the adjacent atmosphere gas of different atmosphere does not mix, the capacity of the gas purifier can be made compact, and the steel strip that passes through the seal roll part It is an object of the present invention to provide a sealing method and a sealing device for atmospheric gas in which no rolling force is generated and slip flaws and biting scratches are not generated by a sealing roll.
[0011]
[Means for Solving the Problems]
The present invention has been made as a result of intensive studies in order to solve the above-described problems, and the gist of the present invention is the following contents as described in the claims.
(1) A method for sealing an atmospheric gas at the inlet and / or outlet of a heat treatment furnace for heat treating a steel strip by enclosing an inert gas,
A plurality of pairs of seal rolls sandwiching the steel strip are disposed,
The pair of seal rolls are shifted in the running direction of the steel strip and installed with a gap more than the maximum thickness of the steel strip,
Atmospheric gas is discharged from between the plurality of sets of seal rolls.
(2) Atmospheric gas discharged from between the plurality of sets of seal rolls is introduced into a gas purifier through an atmospheric gas exhaust pipe, and the inert gas is separated by the gas purifier, and the separated inert gas Is supplied to the heat treatment furnace, the atmospheric gas sealing method according to (1).
(3) From the front side of the region divided by the plurality of sets of seal rolls toward the traveling direction of the steel strip, the first set of seal rolls, between the first set and the second set, the second set of seal rolls The pressure A on the first set of seal rolls, the pressure B on the first set and the second set B, and the pressure C on the second set of seal rolls are the following formula (1) or formula (2): The atmosphere gas sealing method according to (1) or (2), wherein the inert gas is sucked from between the first set and the second set of seal rolls while being controlled to satisfy the equation.

[0012]
(4) An atmospheric gas exhaust pipe for exhausting atmospheric gas from the first set of seal rolls is installed, and the atmospheric gas exhaust pipe is connected to a mixer and mixed with N ₂ gas and connected to a heat treatment furnace. The atmospheric gas sealing method according to any one of (1) to (3), wherein the gas is blown into an inlet side and an outlet side furnace body.
(5) An atmosphere gas sealing device at the inlet and / or outlet of a heat treatment furnace that encloses an inert gas and heat-treats the steel strip,
A plurality of pairs of seal rolls sandwiching the steel strip are disposed,
An atmosphere gas sealing apparatus characterized in that the pair of seal rolls are shifted in the running direction of the steel strip and are provided with a gap larger than the maximum thickness of the steel strip.
(6) The pair of seal rolls is characterized in that the distance L between the rolls at the point where the axis line connecting the shaft centers of the seal rolls and the outer shape of the seal rolls meet the following formula (3) (5) ) Atmosphere gas sealing device.

[0013]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described in detail with reference to FIGS.
1 and 2 are views illustrating a heat treatment furnace provided with the atmospheric gas sealing device of the present invention.
FIG. 3 is a diagram illustrating a sealing portion in the atmospheric gas sealing device of the present invention.
FIG. 4 is a diagram showing the pressure distribution in the furnace when the present invention is adopted.
FIG. 5 is a diagram showing the relationship between the separation dimension of the seal roll and the leak amount.
In FIG. 1, the Example at the time of employ | adopting the sealing method and sealing apparatus of this invention to a continuous annealing furnace is shown.
The continuous annealing furnace includes a heating zone 1, a soaking zone 2, a slow cooling zone 3, a quenching zone 4, an overaging zone 5, and a final cooling zone 6. The steel strip 9 is heated to a predetermined temperature in the heating zone 1, passes through the soaking zone 2, passes through the slow cooling zone 3, the quenching zone 4, and the overaging zone 5 depending on the treatment material, It is cooled to temperature and transported outside the furnace. The sealing device of the present invention is employed between the heating zone 1 and the soaking zone 2.
[0014]
In the heating zone 1, a radiant heating method or a heating device using an open flame burner is adopted as a heating device for the steel strip 9. In the case of jet heating, the atmospheric gas in the furnace is the same as the atmospheric gas used in the soaking zone 2, so there is no need to install a sealing device between the heating zone 1 and the soaking zone 2; When the steel strip 9 is heated, the atmosphere gas in the heating zone 1 becomes a weakly oxidizing atmosphere, so that it is necessary to seal the soaking zone 2 connected to the heating zone 1. In FIG. 1, a seal roll type sealing device is arranged at the throat portion connecting the heating zone 1 and the soaking zone 2. Two pairs of the seal rolls are arranged on the upper and lower sides with the steel strip 9 in between, and two sets are arranged at intervals in the traveling direction of the steel strip 9. An atmospheric gas exhaust pipe 13 for exhausting the atmospheric gas is connected from this point.
[0015]
The seal roll is shifted in the running direction of the steel strip with the steel strip sandwiched above and below the steel strip, and the surface of the seal roll is arranged with a gap of the maximum thickness of the steel strip passing through the seal roll. In the embodiment, the atmosphere gas is exhausted between two sets of seal rolls. By this sealing device, the atmosphere gas of the adjacent furnace bodies does not enter each furnace body. Moreover, as shown in FIG. 3, the seal roll 10-2 arrange | positioned on the upper surface of the steel strip 9 among the seal rolls arrange | positioned up and down is shifted from the seal roll 10-1 arrange | positioned on the lower surface of the steel strip 9. . As a result, the seal roll 10-2 located on the upper surface of the steel strip 9 is merely brought into contact with the steel strip 9, and when it is arranged vertically, the steel strip 9 is sandwiched by changing the plate thickness, etc. There is a concern that the steel strip 9 may be wrinkled due to the slip of the roll 10-1.10-2 or the inclusion of foreign matter, and the seal roll 10-2 disposed on the upper side is slightly increased in addition to the change in the plate thickness. It will be arranged with a gap in between. Even in this state, there is no problem with the sealing method of the present invention, but the upper seal roll 10-2 of the upper and lower seal rolls is shifted in the traveling direction of the steel strip 9 in order to further improve the sealing performance. Even if the plate thickness of the steel strip 9 changes by shifting the upper seal roll 10-2, the steel strip 9 is not sandwiched between the seal rolls, so that wrinkles caused by the seal roll to the steel strip 9 do not occur.
[0016]
Further, in FIG. 1, the sealing device 10 of the present invention is arranged at the inlet and outlet in the quench zone 4. As a cooling method for the quench zone 4, a gas jet circulation type cooling device is employed. In order to increase the cooling capacity, the steel strip is rapidly cooled using a refrigerant having a hydrogen concentration of 50% or more as the atmospheric gas. In this case, since the atmospheres of the slow cooling zone 3 and the overaging zone 5 connected before and after the quenching zone 4 are different from each other, the sealing device 10 of the present invention is arranged at the inlet and outlet of the quenching zone 4. A specific example is shown in FIG.
[0017]
In FIG. 2, the steel strip 9 that has passed through the slow cooling zone 3 is conveyed into the quenching zone 4 by the top roll 7 at the entrance of the quenching zone 4 through the top roll 7 on the outlet side of the slow cooling zone 3. The transported steel strip 9 is rapidly cooled to a predetermined temperature by spraying a coolant onto the steel strip by a cooling device 12 arranged in the quenching zone 4, and is transferred to the next chamber through a bottom roll 8 arranged at the exit of the quenching zone 4. Be transported. In FIG. 2, the overaging zone 5 is connected, but depending on the processing form, there may be a final cooling zone.
The top roll 7 on the exit side of the slow cooling zone 3 and the top roll 7 on the entry side of the quench zone 4 are connected by a throat 11, and the steel strip 9 is conveyed into the throat 11 and conveyed to the quench zone 4. Two pairs of seal rolls are arranged with a gap between the pair of seal rolls 10-1.10-2 on the upper and lower sides of the throat 11 with the steel strip 9 interposed therebetween. The seal roll 10-1.10-2 may be arranged so that the seal roll surface is in contact with the upper and lower surfaces of the steel strip, but as shown in FIG. You may shift and arrange | position to the running direction of the steel strip 9 with respect to 10-1. In FIG. 3, two pairs of seal rolls in which the upper seal roll 10-2 is shifted in the traveling direction of the steel strip 9 are arranged. And the atmospheric gas discharge pipe 13 which discharges atmospheric gas from between this pair of seal rolls is installed. The atmospheric gas in the quenching zone 4 is used with a hydrogen concentration of 50% or more, and the slow cooling zone 3 is an atmosphere gas in which the hydrogen concentration is 5 to 10% and the remaining nitrogen gas is mixed. The atmospheric gas sucked by the atmospheric gas discharge pipe 13 is separated into hydrogen gas and nitrogen gas by the gas purification device, and the hydrogen gas is returned to the quenching zone 4 and circulated for use. On the other hand, the sealing device 10 is similarly arranged on the exit side of the quench zone 4 and used in the same manner as described above.
[0018]
In addition, when the sealing device 10 is installed between the annealing zone 3 and the quenching zone 4 as shown by the solid line in FIG. The atmosphere gas is discharged from between the seal rolls by adjusting the pressure B <the pressure C on the quenching zone side (1). For example, by adjusting the pressure on the slow cooling zone 3 side to 1 mmAq, the pressure between the sealing rolls to 1.5 mmAq, and the pressure on the quenching zone 4 side to 2 mmAq, the atmosphere without sucking the atmosphere gas on the slow cooling zone 4 side Gas can be discharged. By discharging the atmospheric gas by adjusting the pressure in this way, the atmospheric gas having a high hydrogen concentration can be sucked and supplied to the gas purification device 16, so that the capacity of the gas purification device 16 can be made compact. Further, an atmospheric gas discharge pipe 18 for discharging atmospheric gas leaking from the seal roll is installed between the slow cooling zone 3 on the side of the slow cooling zone 3 and the sealing device 10.
Atmospheric gas leaking to the slow cooling zone 3 side is sucked by this atmospheric gas discharge pipe 18, supplied to a mixer 19 connected to the atmospheric gas discharge pipe 18, mixed with nitrogen gas to adjust the concentration, and the slow cooling zone 3 and reused as an atmospheric gas in the slow cooling zone 3.
[0019]
Similarly, on the exit side of the quenching zone 4, the exit side of the quenching zone 4 and the entry side of the overaging zone 5 are connected, and the bottom roll at the inlet of the overaging zone 5 is connected to the inside of the throat through the bottom roll of the quenching zone 4 side. To transport the steel strip 9. And, two pairs of seal rolls are arranged on the upper and lower surfaces of the steel strip 9 with a gap in the traveling direction of the steel strip. . An atmosphere gas discharge pipe 13 for discharging the atmosphere gas from between the seal rolls is provided to suck the atmosphere gas. The sucked atmospheric gas is separated by a gas purifier 16 connected to the atmospheric gas discharge pipe 13, and the separated hydrogen gas is introduced into the quenching zone 4 and reused as a refrigerant.
[0020]
In addition, an atmospheric gas exhaust pipe 18 that discharges leaked atmospheric gas from the sealing device 10 to the overaging zone 5 side is provided on the exit side of the quenching zone 4 and on the entry side of the overaging zone 5. The leaking atmosphere gas is sucked by the atmosphere gas discharge pipe 18 and introduced into the mixer 19 connected to the atmosphere gas discharge pipe 18 to adjust the concentration of the atmosphere gas and introduce it into the overaging zone 5.
The pressure balance of the sealing device installed between the quench zone 4 and the overaging zone 5 is as shown by the dotted line in FIG. The pressure C at the side of the quenching zone 4 is adjusted to 2 mmAq, the pressure B between the seal rolls is adjusted to 1.5 mmAq, and the pressure A at the side of the overaging zone 5 is adjusted to 1 mmAq. By adjusting in this way, the atmospheric gas on the overaging zone 5 side does not enter the quenching zone 4.
Further, by adjusting the pressure in this way, the atmospheric gas sucked from between the seal rolls can suck the high hydrogen concentration atmospheric gas on the quenching zone 4 side and supply it to the gas purifier 16. The capacity can be made compact.
[0021]
FIG. 3 shows a specific example of the sealing device of the present invention.
In FIG. 3, when the steel strip 9 is traveling in the direction of the arrow, the steel strip 9 is arranged at the lower part of the steel strip 9 so that the surface of the seal roll 10-1 contacts the lower surface of the steel strip 9. And the seal roll 10-2 corresponding to the seal roll 10-1 is arrange | positioned so that the surface of the seal roll 10-2 may contact the upper surface of the steel strip 9. FIG. The seal roll 10-2 disposed on the upper surface of the steel strip 9 is spaced apart from the seal roll 10-1 disposed at the lower portion of the steel strip in the traveling direction of the steel strip.
This separation dimension is set at _{t max ≦ L ≦ 50 (mm} ) ··· ▲ 3 ▼ range.
Here, t _max is the maximum thickness (mm) of the material to be processed, and L is the distance between rolls (mm). By setting within this range, wrinkles can be prevented from occurring due to contact wrinkles by the seal rolls and biting of foreign matter. That is, when the seal rolls 10-1 and 10-2 are arranged to face each other with the steel strip 9 interposed therebetween, the gap between the upper and lower seal rolls is installed in the gap with the maximum thickness of the plate to pass. However, when the steel strip 9 having the maximum plate thickness passes between the upper and lower seal rolls, the steel strip 9 is sandwiched between the upper and lower seal rolls, and it becomes easy to generate scrapes and foreign material bites into the steel strip. Therefore, as shown in FIG. 3, by shifting by a gap exceeding the maximum plate thickness passing through the seal roll in the running direction of the steel strip from the lower seal roll 10-1, the steel strip passes without causing the phenomenon due to the upper and lower seal rolls. Can also be prevented. Moreover, since the sealing effect will deteriorate as shown in FIG. 5 if the separation distance to the running direction of the steel strip of the upper seal roll 10-2 exceeds 50 mm, it is necessary to make it 50 mm or less.
[0022]
【The invention's effect】
As described above, two pairs of one pair of seal rolls are arranged so that the atmosphere gas is exhausted from between the seal rolls and circulated for use. Therefore, the atmosphere gases of adjacent different atmospheres are not mixed. . In addition, since the furnace pressure is adjusted and exhausted, the capacity of the gas purifier can be made compact.
In addition, since the seal rolls are separated from each other in the running direction of the steel strip, no rolling force is generated on the steel strip passing through the seal roll section, and no slip wrinkles or bite scratches are generated by the seal roll. It has a remarkable effect that is useful in the industry.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a heat treatment furnace provided with an atmospheric gas sealing device of the present invention.
FIG. 2 is a diagram illustrating a heat treatment furnace in which the atmospheric gas sealing device of the present invention is installed.
FIG. 3 is a diagram illustrating a seal portion in the atmospheric gas sealing device of the present invention.
FIG. 4 is a diagram showing a furnace pressure distribution when the present invention is employed.
FIG. 5 is a diagram showing a relationship between a separation dimension of a seal roll and a leak amount.
[Brief description of symbols]
1 ... heating zone, 2 ... soaking zone, 3 ... slow cooling zone, 4 ... quenching zone,
5 ... Overaging zone, 6 ... Final cooling zone, 7 ... Top roll,
8 ... Bottom roll, 9 ... Steel strip, 10 ... Sealing device,
10-1 ... seal roll, 10-2 ... seal roll,
10-3 ... Seal plate, 11 ... Throat, 12 ... Cooling device,
DESCRIPTION OF SYMBOLS 13 ... Atmospheric gas exhaust pipe, 14 ... Orifice, 15 ... Flow control valve, 16 ... Gas purification apparatus, 17 ... Outdoor exhaust pipe,
18 ... ambient gas exhaust pipe, 19 ... mixer, 20 ... _{N 2} gas feed pipe, 21 ... Mixed gas inlet tube

Claims (6)

A method for sealing an atmospheric gas at the inlet and / or outlet of a heat treatment furnace that heats a steel strip by enclosing an inert gas,
A plurality of pairs of seal rolls sandwiching the steel strip are disposed,
The pair of seal rolls are shifted in the running direction of the steel strip and installed with a gap more than the maximum thickness of the steel strip,
Atmospheric gas is discharged from between the plurality of sets of seal rolls. An atmosphere gas discharged from between the plurality of sets of seal rolls is introduced into a gas purification device through an atmosphere gas exhaust pipe, and the inert gas is separated by the gas purification device, and the separated inert gas is subjected to the heat treatment. The atmosphere gas sealing method according to claim 1, wherein the atmosphere gas is supplied to a furnace. The region divided by the plurality of sets of seal rolls is the first set of seal rolls from the front toward the traveling direction of the steel strip, and the second set of seal rolls between the first set and the second set. At that time, the pressure A on the first set of seal rolls, the pressure B between the first and second sets, and the pressure C on the second set of seal rolls satisfy the following formula (1) or formula (2): 3. The atmospheric gas sealing method according to claim 1, wherein the inert gas is sucked from between the first set and the second set of seal rolls under control.

Wherein the first set ambient gas discharge pipe for discharging the atmospheric gas from the seal roll side of the installed, the incoming side and the ambient gas exhaust pipe are connected to the heat treatment furnace and mixed with N ₂ gas coupled to the mixer The atmospheric gas sealing method according to any one of claims 1 to 3, wherein the gas is blown into a discharge furnace body. An atmosphere gas sealing device at an inlet and / or an outlet of a heat treatment furnace for heat treating a steel strip by enclosing an inert gas,
A plurality of pairs of seal rolls sandwiching the steel strip are disposed,
An atmosphere gas sealing apparatus characterized in that the pair of seal rolls are shifted in the running direction of the steel strip and are provided with a gap larger than the maximum thickness of the steel strip. 6. The pair of seal rolls according to claim 5, wherein a distance L between the rolls at a point where the axis line connecting the shaft centers of the seal rolls and the outer shape of the seal rolls meet the following formula (3). Atmosphere gas seal device.

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