JP2010255056A - Method of controlling furnace atmosphere in heat treatment furnace - Google Patents

Method of controlling furnace atmosphere in heat treatment furnace Download PDF

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JP2010255056A
JP2010255056A JP2009107482A JP2009107482A JP2010255056A JP 2010255056 A JP2010255056 A JP 2010255056A JP 2009107482 A JP2009107482 A JP 2009107482A JP 2009107482 A JP2009107482 A JP 2009107482A JP 2010255056 A JP2010255056 A JP 2010255056A
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furnace
atmosphere
oxygen concentration
gas
heat treatment
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Takashi Ishimoto
崇 石本
Takaya Ochiai
孝哉 落合
Kenji Shimizu
健司 清水
Masato Ogawa
正人 小川
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Daido Steel Co Ltd
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Daido Steel Co Ltd
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<P>PROBLEM TO BE SOLVED: To provide a method of controlling furnace atmosphere in a heat treatment furnace by which, in the heat treatment furnace performing the heat treatment of a treatment target article in inert gas atmosphere, oxygen concentration in furnace atmospheric gas is quickly returned to a target value or lower by suppressing a rise in the oxygen concentration. <P>SOLUTION: In the method of controlling the furnace atmosphere in the heat treatment furnace 1 by which the dew point of the furnace atmospheric gas is controlled to be a target value or lower by adjusting feeding quantity of the inert gas into the furnace, the control is performed in such a manner that by adjusting the feeding quantity of the hydrogen gas into the furnace based on the actually measured oxygen concentration in the furnace atmospheric gas, hydrogen gas is allowed to react with the oxygen in the furnace atmospheric gas, consequently the oxygen concentration in the furnace atmospheric gas becomes the target value or lower without causing the exceeding of the dew point beyond the target value. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

この発明は、不活性ガス雰囲気中で処理品の熱処理を行う熱処理炉における炉内雰囲気の制御方法に関し、さらに詳しくは、炉内雰囲気ガスの露点及び酸素濃度の制御方法に関する。   The present invention relates to a method for controlling a furnace atmosphere in a heat treatment furnace that performs heat treatment of a processed product in an inert gas atmosphere, and more particularly to a method for controlling the dew point and oxygen concentration of the furnace atmosphere gas.

棒状、線状、板状などの各種形状を有し炭素鋼や特殊鋼などからなる鋼材は、加工性改善のために焼鈍処理されるが、従来の焼鈍では、雰囲気中での加熱時には、鋼材に脱浸炭が生じないように、例えば吸熱型ガス等を調整して、ＣＯ及びＣＯ２濃度の比率によって決まるＣＰ値（カーボンポテンシャル）を、常時炉温や鋼種に応じて変更する雰囲気制御を行う必要があった。そこで、より雰囲気制御の容易な窒素ガス等の不活性ガス雰囲気中での焼鈍も採用されるようになり、それに適した構造の低露点雰囲気炉も提案されている（例えば特許文献１参照。）。 Steel materials made of carbon steel, special steel, etc. that have various shapes such as rods, wires, and plates are annealed to improve workability. In conventional annealing, steel materials are used when heated in an atmosphere. In order to prevent decarburization, the endothermic gas is adjusted, for example, and the CP value (carbon potential) determined by the ratio of CO and CO 2 concentration is constantly changed according to the furnace temperature and steel type. There was a need. Therefore, annealing in an inert gas atmosphere such as nitrogen gas, which is easier to control the atmosphere, has come to be adopted, and a low dew point atmosphere furnace having a structure suitable for this is also proposed (see, for example, Patent Document 1). .

特開平５−５１２４号公報JP-A-5-5124

ところで上記の炉内の不活性ガス雰囲気は、鋼材の脱炭及び酸化防止のため、例えば露点−５０℃以下、酸素濃度１ｐｐｍ以下という、低露点・低酸素濃度の雰囲気とする必要があり、この雰囲気実現のために、例えば露点−７０℃〜−８０℃、酸素濃度約１ｐｐｍの高純度の窒素ガスを炉内に送入して炉内雰囲気を置換することが行われている。   By the way, in order to prevent the decarburization and oxidation of the steel material, the inert gas atmosphere in the furnace needs to be an atmosphere having a low dew point and a low oxygen concentration, for example, a dew point of −50 ° C. or lower and an oxygen concentration of 1 ppm or lower. In order to realize the atmosphere, for example, high purity nitrogen gas having a dew point of −70 ° C. to −80 ° C. and an oxygen concentration of about 1 ppm is sent into the furnace to replace the furnace atmosphere.

ところがこの窒素ガスの送入のみによっては、炉内雰囲気ガスの露点は目標値（−５０℃）以下を達成できるものの、炉内雰囲気ガスの酸素濃度の目標値（１ｐｐｍ）以下を達成するには、長時間にわたる大量の窒素ガスによる置換が必要であった。例えば炉操業中に、微量の大気分が処理品（鋼材）に付着する等して炉内に侵入した場合は、露点よりも酸素濃度の方がより早く目標値を外れる。例として、酸素２１％に対し水分の容積割合が約４％である露点３０℃の大気が、炉内の容積の１万分の１の容積分炉内に侵入した場合、酸素濃度は２１ｐｐｍ上昇するのに対し、水分の容積割合は僅か４ｐｐｍしか上昇しない（−６０℃の露点の雰囲気ガスの場合、約−５８℃に上昇する程度）。このように、大気が侵入した場合、露点よりも酸素濃度の方が目標値以上となりやすく、従来のように窒素ガスの送入だけでは、長時間にわたるパージが必要であり、処理品の酸化や脱炭を生じさせない酸素濃度まで処理品の加熱を待つ必要があった。   However, the dew point of the atmosphere gas in the furnace can achieve the target value (−50 ° C.) or less by only feeding the nitrogen gas, but in order to achieve the target value (1 ppm) or less of the oxygen concentration of the atmosphere gas in the furnace. The replacement with a large amount of nitrogen gas for a long time was necessary. For example, when a very small amount of air enters the furnace during operation of the furnace due to adhesion to the treated product (steel material), the oxygen concentration deviates from the target value earlier than the dew point. As an example, when an atmosphere having a dew point of 30 ° C. with a water volume ratio of about 4% with respect to 21% oxygen enters the furnace by a volume of 1 / 10,000 of the furnace volume, the oxygen concentration increases by 21 ppm. On the other hand, the volume ratio of water increases only by 4 ppm (in the case of an atmospheric gas having a dew point of −60 ° C., it increases to about −58 ° C.). In this way, when the air enters, the oxygen concentration tends to be higher than the target value rather than the dew point, and it is necessary to purge for a long time just by feeding nitrogen gas as in the conventional case. It was necessary to wait for the treated product to be heated to an oxygen concentration that does not cause decarburization.

この発明は上記の点にかんがみてなされたもので、不活性ガス雰囲気中で処理品の熱処理を行う熱処理炉において、炉内雰囲気ガスの酸素濃度の上昇を抑制して迅速に目標値以下に復帰させることができる、熱処理炉における炉内雰囲気制御方法を提供することを目的とする。   The present invention has been made in view of the above points, and in a heat treatment furnace that performs heat treatment of a processed product in an inert gas atmosphere, the increase in the oxygen concentration of the atmosphere gas in the furnace is suppressed to quickly return to a target value or less. It is an object of the present invention to provide a furnace atmosphere control method in a heat treatment furnace.

上記目的を達成するためにこの発明の熱処理炉における炉内雰囲気の制御方法は、不活性ガスの炉内への送入量を調節することにより、炉内雰囲気ガスの露点を目標値以下に制御するようにした熱処理炉における炉内雰囲気の制御方法において、実測した炉内雰囲気ガスの酸素濃度に基づいて水素ガスの炉内への送入量を調節することにより、この水素ガスと炉内雰囲気ガス中の酸素とを反応させて、露点が前記目標値を越えることなく炉内雰囲気ガスの酸素濃度が目標値以下となるように制御することを特徴とする。   In order to achieve the above object, the method for controlling the atmosphere in the heat treatment furnace of the present invention controls the dew point of the atmosphere gas in the furnace to a target value or less by adjusting the amount of inert gas fed into the furnace. In the method of controlling the furnace atmosphere in the heat treatment furnace, the hydrogen gas and the furnace atmosphere are adjusted by adjusting the amount of hydrogen gas fed into the furnace based on the measured oxygen concentration of the furnace atmosphere gas. It is characterized by reacting with oxygen in the gas and controlling so that the oxygen concentration of the atmosphere gas in the furnace is not more than the target value without the dew point exceeding the target value.

このように構成することにより、炉内雰囲気ガスの酸素濃度に基づいて水素ガスを炉内へ送入し、この水素ガスと炉内雰囲気ガス中の酸素とを反応させることにより、上記酸素は消費されて酸素濃度の上昇が抑制され、不活性ガスの送入のみによる場合に比べて遙かに短時間で酸素濃度を目標値以下に復帰させることができる。そしてこの水素ガスと炉内の酸素により生成した水分による炉内雰囲気ガスの露点上昇はごく僅かであり、露点が目標値を越えることなく酸素濃度を制御することができるのである。   With this configuration, hydrogen gas is fed into the furnace based on the oxygen concentration in the furnace atmosphere gas, and the oxygen gas is consumed by reacting the hydrogen gas with oxygen in the furnace atmosphere gas. Thus, the increase in oxygen concentration is suppressed, and the oxygen concentration can be returned to the target value or less in a much shorter time than in the case where only the inert gas is fed. The dew point of the atmospheric gas in the furnace due to the water generated by the hydrogen gas and oxygen in the furnace is negligible, and the oxygen concentration can be controlled without the dew point exceeding the target value.

以上説明したようにこの発明によれば、不活性ガス雰囲気中で処理品の熱処理を行う熱処理炉において、炉内雰囲気ガスの酸素濃度の上昇を抑制して迅速に目標値以下に復帰させることができる。   As described above, according to the present invention, in a heat treatment furnace that performs heat treatment of a processed product in an inert gas atmosphere, an increase in the oxygen concentration of the atmosphere gas in the furnace can be suppressed and quickly returned to a target value or less. it can.

この発明の実施の形態の一例を示す熱処理炉の雰囲気制御系統図である。It is an atmosphere control system diagram of a heat treatment furnace showing an example of an embodiment of the present invention. 図１の制御系による雰囲気制御方法の例を示すフローチャートである。It is a flowchart which shows the example of the atmosphere control method by the control system of FIG.

以下図１及び図２に示す一例により、この発明の実施の形態を説明する。図１は熱処理炉の雰囲気制御系統図であり、図中、１は熱処理炉で、周知の炉内加熱手段をそなえ鋼材からなる処理品（図示しない）を所定の不活性ガス雰囲気中で熱処理するものであり、その炉体には、不活性ガス供給管２及び排気管３とともに、水素ガス供給管４が接続され、不活性ガス供給管２には流量調節弁５が、排気管３には排気弁６が、水素ガス供給管４には流量調節弁７が、それぞれ設けてある。そしてこの例においては不活性ガスとして、所定の低露点及び酸素濃度の窒素ガス（例えば露点−７０℃〜−８０℃，酸素濃度約１ｐｐｍの前述した高純度の窒素ガス）を用いている。   Hereinafter, an embodiment of the present invention will be described with reference to an example shown in FIGS. FIG. 1 is an atmosphere control system diagram of a heat treatment furnace. In the figure, reference numeral 1 denotes a heat treatment furnace, which includes a known in-furnace heating means and heat-treats a processed product (not shown) made of steel in a predetermined inert gas atmosphere. A hydrogen gas supply pipe 4 is connected to the furnace body together with an inert gas supply pipe 2 and an exhaust pipe 3. A flow rate adjusting valve 5 is connected to the inert gas supply pipe 2, and an exhaust pipe 3 is connected to the furnace body. The exhaust valve 6 is provided, and the hydrogen gas supply pipe 4 is provided with a flow rate adjusting valve 7. In this example, a nitrogen gas having a predetermined low dew point and oxygen concentration (for example, the above-described high purity nitrogen gas having a dew point of −70 ° C. to −80 ° C. and an oxygen concentration of about 1 ppm) is used as the inert gas.

８は、熱処理炉１内の炉圧を連続的に測定する圧力計、９及び１０は炉圧の目標値（上限値及び下限値）を設定する設定部、１１は圧力計８からの炉圧実測値と設定部９からの炉圧目標値との偏差に応じた調節信号を流量調節弁５に出力する調節部、１２は同じく圧力計８からの炉圧実測値と設定部１０からの炉圧目標値との偏差に応じた調節信号を排気弁６に出力する調節部であり、これら各部によって、熱処理炉１への窒素ガスの送入量及び炉内雰囲気ガスの排気量を調節して炉内を所定の炉圧にフィードバック制御する炉圧制御部が構成されている。なおこれら各部による具体的な制御の流れについては、後述するフローチャートにより説明する。   8 is a pressure gauge for continuously measuring the furnace pressure in the heat treatment furnace 1, 9 and 10 are setting units for setting target values (upper limit value and lower limit value) of the furnace pressure, and 11 is a furnace pressure from the pressure gauge 8. An adjustment unit 12 that outputs an adjustment signal corresponding to the deviation between the actual measurement value and the furnace pressure target value from the setting unit 9 to the flow rate control valve 5, is the furnace pressure actual value from the pressure gauge 8 and the furnace from the setting unit 10. It is an adjustment part which outputs the adjustment signal according to the deviation with the pressure target value to the exhaust valve 6, and adjusts the feed amount of the nitrogen gas to the heat treatment furnace 1 and the exhaust amount of the atmospheric gas in the furnace by these parts. A furnace pressure control unit that feedback-controls the inside of the furnace to a predetermined furnace pressure is configured. A specific control flow by these units will be described with reference to flowcharts described later.

また１３は、熱処理炉１内の雰囲気ガスをサンプリングしてその露点を連続的に測定する分析計（露点計）、１４は露点の目標値を設定する設定部であり、この分析計１３の露点実測値は、前記炉圧調節用の調節部１１に入力され、設定部１４からの露点目標値との偏差に応じた調節信号が不活性ガス流量調節用の流量調節弁５に出力されて、露点を所定の目標値以下にフィードバック制御する露点制御部が構成されている。   Reference numeral 13 denotes an analyzer (dew point meter) that samples the atmospheric gas in the heat treatment furnace 1 and continuously measures the dew point thereof. Reference numeral 14 denotes a setting unit that sets a target value of the dew point. The actual measurement value is input to the adjustment unit 11 for adjusting the furnace pressure, and an adjustment signal corresponding to the deviation from the dew point target value from the setting unit 14 is output to the flow rate adjustment valve 5 for adjusting the inert gas flow rate. A dew point control unit is configured to feedback control the dew point to a predetermined target value or less.

一方１５は、熱処理炉１内の雰囲気ガスをサンプリングして酸素濃度を連続的に測定する分析計、１６は炉内の酸素濃度の目標値を設定する設定部、１７は露点目標値（詳しくは酸素濃度制御開始のための基準値）を設定する設定部、１８は、分析計１３からの露点実測値が設定部１７の露点目標値以下のときに、分析計１５からの酸素濃度実測値と設定部１６からの酸素濃度目標値との偏差に応じた調節信号を流量調節弁７に出力する調節部であり、これら各部によって、熱処理炉１への水素ガスの送入量を調節してこの水素ガスと炉内雰囲気ガス中の酸素とを反応させることにより、酸素濃度を目標値以下にフィードバック制御する酸素濃度制御部が構成されている。   On the other hand, 15 is an analyzer that samples the atmospheric gas in the heat treatment furnace 1 and continuously measures the oxygen concentration, 16 is a setting unit that sets a target value of the oxygen concentration in the furnace, and 17 is a dew point target value (in detail) The setting unit 18 for setting the reference value for starting oxygen concentration control) is configured to set the measured oxygen concentration value from the analyzer 15 when the measured dew point value from the analyzer 13 is equal to or less than the dew point target value of the setting unit 17. It is an adjustment unit that outputs an adjustment signal corresponding to the deviation from the oxygen concentration target value from the setting unit 16 to the flow rate adjustment valve 7, and adjusts the amount of hydrogen gas fed into the heat treatment furnace 1 by each of these units. An oxygen concentration control unit that feedback-controls the oxygen concentration to a target value or less by reacting hydrogen gas with oxygen in the furnace atmosphere gas is configured.

次に上記の各制御部による雰囲気制御法を、炉圧，露点及び酸素濃度の各目標値をそれぞれ具体的な数値例として表示した図２のフローチャート、及び図１により説明する。   Next, the atmosphere control method by each control unit described above will be described with reference to the flowchart of FIG. 2 and FIG. 1 in which the furnace pressure, dew point, and oxygen concentration target values are displayed as specific numerical examples.

すなわち、炉内に処理材が装入された熱処理炉１の稼働開始時においては、排気弁６は全閉状態にあり、先ず前記炉圧制御部においては、圧力計８により炉圧を連続的に測定し（ステップ２１）、炉圧実測値がゲージ圧で１５０Ｐａ（下限値）以下であれば調節部１１により流量調節弁５の開度を調節して窒素ガスを炉内へ送入し（ステップ２２，２３）、炉圧実測値がゲージ圧で３００Ｐａ（上限値）以下のときは排気弁６を閉状態に維持し（ステップ２４，２５）、ステップ２４で炉圧実測値が３００Ｐａ（上限値）以上となったら、流量調節弁５を閉じて窒素ガスの供給を停止するとともに、調節部１２により排気弁６を開いてその開度を調節して炉内ガスを排気し（ステップ２６，２７）、炉圧実測値が３００Ｐａ（上限値）以下となったら排気弁６を閉じ（ステップ２４，２５）、これらの連続的な制御によって炉圧は所定の炉圧（１５０〜３００Ｐａ）に維持される。   That is, at the start of operation of the heat treatment furnace 1 in which the treatment material is charged in the furnace, the exhaust valve 6 is in a fully closed state. First, in the furnace pressure control unit, the furnace pressure is continuously increased by the pressure gauge 8. (Step 21), and if the actual measured value of the furnace pressure is 150 Pa (lower limit value) or less in gauge pressure, the adjustment unit 11 adjusts the opening of the flow control valve 5 and feeds nitrogen gas into the furnace ( Steps 22 and 23) When the measured furnace pressure is not more than 300 Pa (upper limit) in gauge pressure, the exhaust valve 6 is kept closed (Steps 24 and 25). In Step 24, the measured furnace pressure is 300 Pa (upper limit). Value)), the flow rate control valve 5 is closed to stop the supply of nitrogen gas, and the adjustment unit 12 opens the exhaust valve 6 to adjust its opening to exhaust the furnace gas (step 26, 27), the furnace pressure measured value is 300 Pa (upper limit) or less Once Tsu closed exhaust valve 6 (step 24, 25), the furnace pressure by these continuous control is maintained at a predetermined furnace pressure (150～300Pa).

一方前記露点制御部及び酸素濃度制御部においては、分析計１３により炉内雰囲気ガスの露点を連続的に測定し（ステップ３１）、露点実測値が−５０℃（目標値）を越えているときは、調節部１１により流量調節弁５の開度を調節して窒素ガスを炉内へ送入し（ステップ３２，３３）、炉内雰囲気ガスの露点を−５０℃（目標値）以下となるように制御する。そして露点実測値が−５０℃（目標値）以下となったら、分析計１５により炉内雰囲気ガスの酸素濃度を連続的に測定（ステップ３４）して得た酸素濃度実測値が、１．０ｐｐｍ（目標値）を越えているときは、調節部１８により流量調節弁７の開度を調節して酸素濃度目標値と酸素濃度実測値との偏差に応じた流量の水素ガスを炉内へ送入する（ステップ３５，３６）。   On the other hand, in the dew point control unit and the oxygen concentration control unit, the dew point of the atmosphere gas in the furnace is continuously measured by the analyzer 13 (step 31), and the measured dew point exceeds −50 ° C. (target value). Adjusts the opening degree of the flow control valve 5 by the adjusting unit 11 and sends nitrogen gas into the furnace (steps 32 and 33), and the dew point of the atmospheric gas in the furnace becomes −50 ° C. (target value) or less. To control. When the measured dew point is -50 ° C. (target value) or less, the measured oxygen concentration obtained by continuously measuring the oxygen concentration in the furnace atmosphere gas with the analyzer 15 (step 34) is 1.0 ppm. When (target value) is exceeded, the opening of the flow rate control valve 7 is adjusted by the adjusting unit 18 and hydrogen gas having a flow rate corresponding to the deviation between the target oxygen concentration value and the actual measured oxygen concentration value is sent into the furnace. (Steps 35 and 36).

この炉内へ送入された水素ガスは、炉内雰囲気ガス中の酸素との反応（２Ｈ２＋Ｏ２＝２Ｈ２Ｏ）により上記酸素を消費させるので、少量の水素ガスの送入により、炉内雰囲気ガスの酸素濃度を低酸素濃度値である１．０ｐｐｍ（目標値）以下に迅速に復帰させることができ、従来のような長時間にわたる大量の窒素ガスの炉内送入は不要となる。例えば、目標とする炉内雰囲気が露点：−５０℃以下、酸素濃度：１ｐｐｍ以下に対し、露点：−６０℃、酸素濃度：３ｐｐｍの場合では、フィードバック制御により、酸素濃度実測値（３ｐｐｍ）が酸素濃度目標値（１ｐｐｍ）になるように、調節部１８により流量調節弁７の開度を調節して酸素濃度目標値と酸素濃度実測値との偏差に応じた流量の水素ガスを炉内へ送入する。そして、酸素濃度実測値（３ｐｐｍ）を酸素濃度目標値（１ｐｐｍ）にするには、理論上、酸素濃度の偏差（２ｐｐｍ）の２倍量である４ｐｐｍに相当する容積の水素ガスを送入する必要がある。この場合、上記反応により２ｐｐｍの酸素が消費されて、炉内の酸素濃度は１ｐｐｍになるのである。またこの場合、上記反応により４ｐｐｍの水分が生成されるが、この水分量は炉内雰囲気ガスの露点を−６０℃から−５８℃に上昇させる程度の微量のものであるので、更なる低露点の窒素ガスの炉内送入は不要であり、水素ガスの送入のみにより炉内雰囲気の制御が可能である。なお、大気の侵入や上記反応による水分の生成等により露点が−５０℃以上になったときは、ステップ３３による窒素ガスの炉内送入により、短時間で露点は目標値以下に復帰させることができる。このようにして、上記のステップ３１〜３６による露点及び酸素濃度の制御を連続的に行うことにより、炉内雰囲気ガスの酸素濃度の上昇を制御して迅速に目標値以下に復帰させることができるのである。 Since the hydrogen gas fed into the furnace consumes the oxygen by reaction with oxygen in the furnace atmosphere gas (2H 2 + O 2 = 2H 2 O), the small amount of hydrogen gas is fed into the furnace. The oxygen concentration of the internal atmosphere gas can be quickly returned to the low oxygen concentration value of 1.0 ppm (target value) or less, and a large amount of nitrogen gas in the furnace for a long period of time as in the prior art becomes unnecessary. . For example, when the target furnace atmosphere has a dew point of −50 ° C. or lower and an oxygen concentration of 1 ppm or lower, and a dew point of −60 ° C. and an oxygen concentration of 3 ppm, the actual oxygen concentration measured value (3 ppm) is obtained by feedback control. The adjustment unit 18 adjusts the opening degree of the flow rate control valve 7 so that the oxygen concentration target value (1 ppm) is obtained, and hydrogen gas having a flow rate corresponding to the deviation between the oxygen concentration target value and the actually measured oxygen concentration value is supplied into the furnace. Send in. Then, in order to change the actual oxygen concentration value (3 ppm) to the target oxygen concentration value (1 ppm), theoretically, a volume of hydrogen gas corresponding to 4 ppm, which is twice the oxygen concentration deviation (2 ppm), is delivered. There is a need. In this case, 2 ppm of oxygen is consumed by the above reaction, and the oxygen concentration in the furnace becomes 1 ppm. Further, in this case, 4 ppm of water is generated by the above reaction, but this amount of water is a minute amount that raises the dew point of the atmospheric gas in the furnace from -60 ° C to -58 ° C. Therefore, it is not necessary to feed nitrogen gas into the furnace, and the atmosphere in the furnace can be controlled only by feeding hydrogen gas. When the dew point becomes -50 ° C or higher due to the intrusion of air or the generation of moisture due to the above reaction, the dew point is returned to the target value or less in a short time by feeding nitrogen gas into the furnace in step 33. Can do. In this way, by continuously controlling the dew point and the oxygen concentration in the above steps 31 to 36, the increase in the oxygen concentration of the furnace atmosphere gas can be controlled and quickly returned to the target value or less. It is.

この発明は上記の例に限定されるものではなく、例えば雰囲気制御系統や制御のフローの具体的構成は上記以外のものとしてもよく、また炉圧，露点，酸素ガス濃度の各目標値なども上記以外の値としてもよい。また上記の例では不活性ガスとして窒素ガスを用いたが、例えばアルゴンガスなどの不活性ガスを用いる熱処理炉にも、この発明は適用できるものである。   The present invention is not limited to the above example. For example, the specific configuration of the atmosphere control system and the control flow may be other than those described above, and the furnace pressure, dew point, oxygen gas concentration target values, etc. It is good also as values other than the above. In the above example, nitrogen gas is used as the inert gas. However, the present invention can be applied to a heat treatment furnace using an inert gas such as argon gas.

１…熱処理炉、２…不活性ガス供給管、３…排気管、４…水素ガス供給管、５…流量調節弁、７…流量調節弁、１１…調節部、１３…分析計、１４…設定部、１５…分析計、１６…設定部、１７…設定部、１８…調節部。   DESCRIPTION OF SYMBOLS 1 ... Heat treatment furnace, 2 ... Inert gas supply pipe, 3 ... Exhaust pipe, 4 ... Hydrogen gas supply pipe, 5 ... Flow control valve, 7 ... Flow control valve, 11 ... Control part, 13 ... Analyzer, 14 ... Setting Part, 15 ... analyzer, 16 ... setting part, 17 ... setting part, 18 ... adjusting part.

Claims (1)

不活性ガスの炉内への送入量を調節することにより、炉内雰囲気ガスの露点を目標値以下に制御するようにした熱処理炉における炉内雰囲気の制御方法において、
実測した炉内雰囲気ガスの酸素濃度に基づいて水素ガスの炉内への送入量を調節することにより、この水素ガスと炉内雰囲気ガス中の酸素とを反応させて、露点が前記目標値を越えることなく炉内雰囲気ガスの酸素濃度が目標値以下となるように制御することを特徴とする熱処理炉における炉内雰囲気の制御方法。 In the method for controlling the furnace atmosphere in the heat treatment furnace in which the dew point of the atmosphere gas in the furnace is controlled to a target value or less by adjusting the amount of inert gas fed into the furnace,
By adjusting the amount of hydrogen gas fed into the furnace based on the measured oxygen concentration in the furnace atmosphere gas, the hydrogen gas reacts with oxygen in the furnace atmosphere gas, and the dew point is the target value. A method for controlling the atmosphere in a furnace in a heat treatment furnace, wherein the oxygen concentration of the atmosphere gas in the furnace is controlled to be equal to or lower than a target value without exceeding.
JP2009107482A 2009-04-27 2009-04-27 Method of controlling furnace atmosphere in heat treatment furnace Pending JP2010255056A (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102876864A (en) * 2012-09-25 2013-01-16 攀钢集团西昌钢钒有限公司 Control system and closed-loop control method for hearth atmosphere of annealing furnace and closed-loop control method
KR20150142602A (en) 2014-06-11 2015-12-22 엔지케이 인슐레이터 엘티디 Heat treatment furnace
CN110699527A (en) * 2019-10-18 2020-01-17 甘肃酒钢集团宏兴钢铁股份有限公司 Operation method of nitrogen interlocking control system for detecting oxygen content on hot galvanizing vertical annealing furnace

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102876864A (en) * 2012-09-25 2013-01-16 攀钢集团西昌钢钒有限公司 Control system and closed-loop control method for hearth atmosphere of annealing furnace and closed-loop control method
KR20150142602A (en) 2014-06-11 2015-12-22 엔지케이 인슐레이터 엘티디 Heat treatment furnace
CN105177251A (en) * 2014-06-11 2015-12-23 日本碍子株式会社 Heat treatment furnace
JP2016001064A (en) * 2014-06-11 2016-01-07 日本碍子株式会社 Heat treatment furnace
CN105177251B (en) * 2014-06-11 2018-03-09 日本碍子株式会社 Heat-treatment furnace
TWI646201B (en) * 2014-06-11 2019-01-01 日商日本碍子股份有限公司 Heat treatment furnace
CN110699527A (en) * 2019-10-18 2020-01-17 甘肃酒钢集团宏兴钢铁股份有限公司 Operation method of nitrogen interlocking control system for detecting oxygen content on hot galvanizing vertical annealing furnace
CN110699527B (en) * 2019-10-18 2021-08-27 甘肃酒钢集团宏兴钢铁股份有限公司 Operation method of nitrogen interlocking control system for detecting oxygen content on hot galvanizing vertical annealing furnace

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