JPH04259324A - Method for controlling atmosphere in continuous type non-oxidizing heat treatment furnace - Google Patents
Method for controlling atmosphere in continuous type non-oxidizing heat treatment furnaceInfo
- Publication number
- JPH04259324A JPH04259324A JP3953091A JP3953091A JPH04259324A JP H04259324 A JPH04259324 A JP H04259324A JP 3953091 A JP3953091 A JP 3953091A JP 3953091 A JP3953091 A JP 3953091A JP H04259324 A JPH04259324 A JP H04259324A
- Authority
- JP
- Japan
- Prior art keywords
- furnace
- gas
- atmosphere
- carbon potential
- heat treatment
- 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.)
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Links
- 230000001590 oxidative effect Effects 0.000 title claims abstract description 12
- 238000000034 method Methods 0.000 title claims description 15
- 238000010438 heat treatment Methods 0.000 title claims description 13
- 238000004868 gas analysis Methods 0.000 claims description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 abstract description 20
- 229910052799 carbon Inorganic materials 0.000 abstract description 20
- 239000000463 material Substances 0.000 abstract description 11
- 238000000137 annealing Methods 0.000 abstract description 6
- 238000007664 blowing Methods 0.000 abstract description 6
- 238000004880 explosion Methods 0.000 abstract description 5
- 230000002950 deficient Effects 0.000 abstract description 4
- 238000005255 carburizing Methods 0.000 abstract 1
- 239000007789 gas Substances 0.000 description 52
- 238000004458 analytical method Methods 0.000 description 4
- 238000005261 decarburization Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 238000000605 extraction Methods 0.000 description 4
- 230000003647 oxidation Effects 0.000 description 4
- 238000007254 oxidation reaction Methods 0.000 description 4
- 238000007796 conventional method Methods 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 239000002801 charged material Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
Abstract
Description
【０００１】0001
【産業上の利用分野】この発明は連続無酸化焼鈍炉等、
炉内雰囲気の適切な制御を必要とする連続式無酸化熱処
理炉の炉内雰囲気制御方法に関する。[Industrial Application Field] This invention is applicable to continuous non-oxidation annealing furnaces, etc.
The present invention relates to a method for controlling the atmosphere in a continuous non-oxidizing heat treatment furnace, which requires appropriate control of the atmosphere in the furnace.
【０００２】0002
【従来の技術】連続式無酸化焼鈍炉では、材料の脱炭お
よび浸炭を防止するため、炉内雰囲気ガスのカーボンポ
テンシャルを適当に保持すべく炉内に吹込む雰囲気調整
ガス（Ｒｘガス、Ｄｘガス等）の量を調整している。炉
内雰囲気ガスのカーボンポテンシャルは、下記数１で表
され、雰囲気ガスのカーボンポテンシャルＰＦが材料の
カーボンポテンシャルより高いと浸炭が発生し、逆に低
い場合は脱炭が発生する。このため、脱浸炭を防止する
ためには、炉内雰囲気ガスのカーボンポテンシャルを予
め決められた値（Ｋ＝１とした場合、±１０〜２０）内
に調整する必要がある。[Prior Art] In a continuous non-oxidizing annealing furnace, in order to prevent decarburization and carburization of materials, atmosphere adjusting gases (Rx gas, Dx gas, (gas, etc.) is being adjusted. The carbon potential of the atmosphere gas in the furnace is expressed by the following equation 1. If the carbon potential PF of the atmosphere gas is higher than the carbon potential of the material, carburization will occur, and if it is lower, decarburization will occur. Therefore, in order to prevent decarburization, it is necessary to adjust the carbon potential of the furnace atmosphere gas to within a predetermined value (±10 to 20 when K=1).
【０００３】0003
【数１】[Math 1]
【０００４】一般に炉内雰囲気制御は、炉内を複数のゾ
ーンに分割し、各ゾーンのガス成分分析を行い、その結
果に基づいて、雰囲気調整ガス成分の調整を行っている
。[0004] Generally, in-furnace atmosphere control involves dividing the inside of the furnace into a plurality of zones, analyzing the gas components of each zone, and adjusting the atmosphere-adjusting gas components based on the results.
【０００５】[0005]
【発明が解決しようとする課題】ところで、連続無酸化
焼鈍炉等における炉内雰囲気の乱れは主として、装入さ
れた材料に付着したＯ２（水分、スケール、空気等）お
よび、装入・抽出時、外部より侵入したＯ２（空気）に
より２ＣＯ＋Ｏ２→２ＣＯ２の反応が起り、炉内のＣＯ
２が増加し炉内雰囲気ガスのカーボンポテンシャルが低
下することにより起る。しかし、炉内のＣＯ２が低い場
合、同じ量のＯ２が侵入しても炉内雰囲気ガスのカーボ
ンポテンシャルは大きく低下し、雰囲気の乱れは一層大
きくなり、また雰囲気制御においても同じ量の雰囲気調
整ガスを吹込んでも炉内ＣＯ２が高い場合は、炉内雰囲
気ガスのカーボンポテンシャルの上昇率は小さく、ＣＯ
２が低い場合は大きくなるため、炉内雰囲気を安定に維
持することが困難であった。[Problems to be Solved by the Invention] Incidentally, disturbances in the atmosphere in the furnace in continuous non-oxidizing annealing furnaces, etc. are mainly caused by O2 (moisture, scale, air, etc.) adhering to the charged material and during charging and extraction. , O2 (air) entering from the outside causes a reaction of 2CO + O2 → 2CO2, and the CO in the furnace
2 increases and the carbon potential of the furnace atmosphere gas decreases. However, if the CO2 in the furnace is low, even if the same amount of O2 enters, the carbon potential of the atmosphere gas in the furnace will be greatly reduced, and the disturbance of the atmosphere will be even greater. If the CO2 in the furnace is high even after injecting CO2, the rate of increase in the carbon potential of the atmosphere gas in the furnace is small, and the
2 becomes large, making it difficult to maintain a stable atmosphere in the furnace.
【０００６】従来、炉内ＣＯ２を確保する方法として、
炉内へ空気を吹込む方法があるが、炉内はＣＯ、Ｈ２等
の可燃性ガスが存在するため、空気吹込量を誤ると爆発
の危険性があり、容易に実施することができない。[0006] Conventionally, as a method for securing CO2 in the furnace,
There is a method of blowing air into the furnace, but since flammable gases such as CO and H2 are present in the furnace, there is a risk of explosion if the amount of air blown is incorrect, and this method cannot be carried out easily.
【０００７】この発明は、前に述べたような実状よりみ
て、無酸化炉における炉内ＣＯ２を一定レベルに保持す
る制御を行うことによって、材料の装入・抽出時の炉内
雰囲気乱れを抑制し、雰囲気調整ガス吹込みによる炉内
雰囲気調整を容易にするとともに、ＣＯ２レベル確保の
ためのガス吹込み時の爆発等の危険を回避し得る炉内雰
囲気制御方法を提案しようとするものである。In view of the above-mentioned actual situation, this invention suppresses the disturbance of the atmosphere inside the furnace during charging and extraction of materials by controlling the CO2 inside the non-oxidation furnace to be maintained at a constant level. The purpose of this paper is to propose a method for controlling the atmosphere in a furnace that makes it easier to adjust the atmosphere in the furnace by injecting atmosphere adjustment gas, and also avoids dangers such as explosions when gas is injected to maintain the CO2 level. .
【０００８】[0008]
【課題を解決するための手段】この発明は炉内雰囲気ガ
スをガス分析計に取込んでガス分析を行い、その分析ガ
ス濃度に応じて雰囲気調整ガスを炉内に吹込んで炉内雰
囲気を制御する方法において、主炉内雰囲気調整ガス供
給系とは別に、副炉内雰囲気調整用のＣＯ２ガス供給系
を設置し、ガス分析計により測定された炉内ＣＯ２濃度
が予め設定された濃度になるよう、前記ＣＯ２ガス供給
系よりＣＯ２ガスを炉内に吹込む方法を要旨とするもの
である。[Means for Solving the Problems] This invention takes in the furnace atmosphere gas into a gas analyzer, performs gas analysis, and controls the furnace atmosphere by blowing atmosphere adjustment gas into the furnace according to the analysis gas concentration. In the method of The gist of this method is to blow CO2 gas into the furnace from the CO2 gas supply system.
【０００９】[0009]
【作用】炉内雰囲気ガスのガス分析は、一般的には一台
のガス分析計を共用し、各ゾーンを切替ながら分析が行
われる。そして、各分析ガス成分濃度に基づいて、雰囲
気調整ガス供給系の調節弁を操作するのである。[Operation] Gas analysis of the furnace atmosphere gas is generally carried out using one gas analyzer while switching between each zone. Then, the control valve of the atmosphere adjustment gas supply system is operated based on the concentration of each analysis gas component.
【００１０】副炉内雰囲気調整用のＣＯ２ガス供給系は
、各ゾーンに対する主炉内雰囲気調整ガス供給系に分岐
接続し、雰囲気調整ガス供給配管を共用することができ
る。各ゾーンの炉内ＣＯ２濃度を適切に制御する場合は
、ガス分析計により炉内のＣＯ、ＣＯ２濃度を測定し、
炉内ＣＯ２濃度が設定値になるようＣＯ２ガス供給系の
調節弁を操作する。[0010] The CO2 gas supply system for adjusting the atmosphere in the auxiliary furnace can be branched and connected to the main furnace atmosphere adjustment gas supply system for each zone, so that the atmosphere adjustment gas supply piping can be shared. To appropriately control the CO2 concentration in the furnace in each zone, measure the CO and CO2 concentrations in the furnace with a gas analyzer,
Operate the control valve of the CO2 gas supply system so that the CO2 concentration in the furnace reaches the set value.
【００１１】炉内ＣＯ２の設定値は、０．３〜０．４％
程度とする。これは、材料装入時、炉内に持込むＯ２に
より２ＣＯ＋Ｏ２→２ＣＯ２の反応が起り、ＣＯの低下
が約０．３％、ＣＯ２の上昇が０．０２％となり、この
時の炉内雰囲気ガスのカーボンポテンシャルの変動量は
、前記数１でＫ＝１とした時、炉内ＣＯ２が０．３％の
時は−１９となり品質上問題の限界であるが、炉内ＣＯ
２が０．２％の時は−２４となり、品質上不良品発生の
可能性があるためである。[0011] The set value of CO2 in the furnace is 0.3 to 0.4%.
degree. This is because when charging materials, the O2 brought into the furnace causes a reaction of 2CO + O2 → 2CO2, resulting in a decrease in CO of about 0.3% and an increase in CO2 of 0.02%. The amount of variation in carbon potential is -19 when the in-furnace CO2 is 0.3% when K = 1 in the above equation 1, which is the limit of quality problems, but the in-furnace CO2
This is because when 2 is 0.2%, it becomes -24, which may result in defective products in terms of quality.
【００１２】このように、炉内ＣＯ２が一定レベル以下
に低下しないよう制御することにより、材料装入・抽出
時の炉内雰囲気の乱れを抑制し、雰囲気調整ガスの吹込
みによる炉内雰囲気調整が容易となる。また、不燃性の
ＣＯ２ガスを用いることにより、爆発等の危険性も皆無
である。[0012] In this way, by controlling the CO2 in the furnace so that it does not fall below a certain level, disturbances in the furnace atmosphere during material charging and extraction can be suppressed, and the atmosphere in the furnace can be adjusted by blowing atmosphere adjustment gas. becomes easier. Furthermore, by using nonflammable CO2 gas, there is no risk of explosion or the like.
【００１３】[0013]
【実施例】図１はこの発明方法を実施するための装置構
成例を示す概略図であり、１は材料搬送方向に複数のゾ
ーンに分割された連続式無酸化焼鈍炉、２は材料、３は
サンプルガス切替器、４はＣＯ分析計、５はＣＯ２分析
計、６は炉内雰囲気ガスのカーボンポテンシャル調節計
、７はＣＯ２調節計、８はＲｘガス供給配管系、９はＣ
Ｏ２ガス供給配管系であり、ＣＯ２ガス供給系９は各Ｒ
ｘガス供給系８毎に設けられている。[Example] Fig. 1 is a schematic diagram showing an example of the configuration of an apparatus for carrying out the method of the present invention, in which 1 is a continuous non-oxidizing annealing furnace divided into a plurality of zones in the material transport direction, 2 is a material; is a sample gas switch, 4 is a CO analyzer, 5 is a CO2 analyzer, 6 is a carbon potential controller for the furnace atmosphere gas, 7 is a CO2 controller, 8 is an Rx gas supply piping system, 9 is a C
This is an O2 gas supply piping system, and the CO2 gas supply system 9 is connected to each R
It is provided for each x gas supply system 8.
【００１４】すなわち、連続式無酸化焼鈍炉１内に、Ｒ
ｘガス（無酸化雰囲気ガス）が流量調節弁Ｖ１を有する
供給配管系８より供給されるとともに、ＣＯ２ガスが流
量調節弁Ｖ２を有する供給配管系９より供給されるよう
に構成されている。サンプルガス切替器３は、各ゾーン
に対して配設されたサンプリング管３−１を介してサン
プリングされる炉内ガスを、分析対象ゾーン毎に切替え
てＣＯ分析計４およびＣＯ２分析計５に供給するごく構
成されている。That is, in the continuous non-oxidation annealing furnace 1, R
The configuration is such that x gas (non-oxidizing atmospheric gas) is supplied from a supply piping system 8 having a flow rate control valve V1, and CO2 gas is supplied from a supply piping system 9 having a flow rate control valve V2. The sample gas switching device 3 switches the furnace gas sampled via the sampling pipe 3-1 arranged for each zone for each zone to be analyzed and supplies it to the CO analyzer 4 and the CO2 analyzer 5. It's extremely structured.
【００１５】ＣＯ分析計４、ＣＯ２分析計５からの分析
結果は、それぞれ実績値としてカーボンポテンシャル調
節計６に与えられ、ここで前記式１により炉内雰囲気ガ
スのカーボンポテンシャルが算出され、その値と設定値
との比較がなされ、その差に応じて流量調節信号が流量
調節弁Ｖ１に出力される。また同時に、ＣＯ２分析値が
ＣＯ２調節計７に与えられ、ここで設定値と比較され、
炉内ＣＯ２濃度が設定値になるよう、流量調節信号が流
量調節弁Ｖ２に出力されるように構成されている。The analysis results from the CO analyzer 4 and the CO2 analyzer 5 are respectively given as actual values to the carbon potential controller 6, where the carbon potential of the furnace atmosphere gas is calculated using the above formula 1, and the value is and a set value, and a flow rate adjustment signal is outputted to the flow rate adjustment valve V1 in accordance with the difference. At the same time, the CO2 analysis value is given to the CO2 controller 7, where it is compared with the set value,
The flow rate adjustment signal is configured to be output to the flow rate adjustment valve V2 so that the CO2 concentration in the furnace becomes a set value.
【００１６】[0016]
【実施例１】図１の制御系により、連続式無酸化熱処理
炉（炉長４０ｍ、ゾーン数１０）の炉内雰囲気制御を行
った時の熱処理履歴を図２に示す。また、比較のため、
従来法による熱処理履歴を図３に示す。本実施例におけ
る熱処理条件を表１にそれぞれ示す。[Example 1] FIG. 2 shows a heat treatment history when the atmosphere in a continuous non-oxidizing heat treatment furnace (furnace length: 40 m, number of zones: 10) was controlled using the control system shown in FIG. 1. Also, for comparison,
Figure 3 shows the heat treatment history by the conventional method. Table 1 shows the heat treatment conditions in this example.
【００１７】図２、図３の結果より明らかなごとく、す
なわち、従来法による場合は、炉内ＣＯ２が目標値０．
３％より低い０．２％であるため炉内雰囲気ガスのカー
ボンポテンシャルが制御不能となり、目標値と大幅にず
れたのに対し、本発明法によれば、炉内ＣＯ２を約０．
３％と高く保持できるため炉内雰囲気ガスのカーボンポ
テンシャル値をほぼ目標値に近付けることができ、炉内
雰囲気を安定に保持することができた。その結果、不良
品の発生頻度として、従来５％であったものが、３％に
低減した。As is clear from the results shown in FIGS. 2 and 3, in the case of the conventional method, the CO2 in the furnace reaches the target value of 0.
Since it was 0.2%, which is lower than 3%, the carbon potential of the atmosphere gas in the furnace became uncontrollable and deviated significantly from the target value.However, according to the method of the present invention, the CO2 in the furnace was reduced to about 0.2%.
Since the carbon potential value of the furnace atmosphere gas could be maintained as high as 3%, the carbon potential value of the furnace atmosphere gas could be brought close to the target value, and the furnace atmosphere could be maintained stably. As a result, the frequency of defective products has been reduced from 5% to 3%.
【００１８】[0018]
【表１】[Table 1]
【００１９】[0019]
【発明の効果】以上説明したごとく、この発明方法によ
れば、炉内雰囲気ガスのカーボンポテンシャルを一定レ
ベルに保持することができるので、材料の装入、抽出時
の炉内雰囲気の乱れを抑制し安定に維持することが可能
となり、脱炭および浸炭による不良品の発生を大幅に少
なくできる。また、この発明はＲＸガス吹込みによる炉
内雰囲気調整が容易であるとともに、ＣＯ２レベル確保
のためのガス吹込み時の爆発の危険性もなく安全性の面
でも有利である。[Effects of the Invention] As explained above, according to the method of this invention, the carbon potential of the furnace atmosphere gas can be maintained at a constant level, thereby suppressing disturbances in the furnace atmosphere during charging and extraction of materials. This makes it possible to maintain stable performance, and significantly reduces the occurrence of defective products due to decarburization and carburization. Further, the present invention is advantageous in terms of safety because it is easy to adjust the atmosphere inside the furnace by blowing in RX gas, and there is no risk of explosion when gas is blowing in to ensure the CO2 level.
【図１】この発明法を実施するための装置構成例を示す
概略図である。FIG. 1 is a schematic diagram showing an example of an apparatus configuration for carrying out the method of the present invention.
【図２】この発明法により無酸化熱処理炉の炉内雰囲気
制御を行った時の熱処理履歴を示す図である。FIG. 2 is a diagram showing a heat treatment history when controlling the atmosphere in a non-oxidizing heat treatment furnace according to the method of the present invention.
【図３】従来法により無酸化熱処理炉の炉内雰囲気制御
を行った時の熱処理履歴を示す図である。FIG. 3 is a diagram showing a heat treatment history when controlling the atmosphere in a non-oxidizing heat treatment furnace using a conventional method.
１ 連続式無酸化熱処理炉
２ 材料
４ ＣＯ分析計
５ ＣＯ２分析計
６ カーボンポテンシャル調節計７ ＣＯ
２調節計
８ ＲＸガス供給配管系
９ ＣＯ２ガス供給配管系1 Continuous non-oxidation heat treatment furnace 2 Material 4 CO analyzer 5 CO2 analyzer 6 Carbon potential controller 7 CO
2 Controller 8 RX gas supply piping system 9 CO2 gas supply piping system
Claims (1)
気調整ガスを吹込み、炉内雰囲気ガスをガス分析計に取
込んでガス分析を行うとともに、各分析ガス成分濃度に
基づいて炉内雰囲気を制御する方法において、主炉内雰
囲気調整ガス供給系とは別に、副炉内雰囲気調整用のＣ
Ｏ２ガス供給系を設置し、ガス分析計により測定された
炉内ＣＯ２濃度が予め設定された濃度になるよう、前記
ＣＯ２ガス供給系よりＣＯ２ガスを炉内に吹込むことを
特徴とする連続式無酸化熱処理炉の炉内雰囲気制御方法
。Claim 1: A main furnace atmosphere adjustment gas is blown into a continuous non-oxidizing heat treatment furnace, and the furnace atmosphere gas is taken into a gas analyzer for gas analysis. In the method for controlling the internal atmosphere, in addition to the main furnace atmosphere adjustment gas supply system, a gas supply system for adjusting the atmosphere in the auxiliary furnace
A continuous type characterized in that an O2 gas supply system is installed and CO2 gas is blown into the furnace from the CO2 gas supply system so that the CO2 concentration in the furnace measured by a gas analyzer becomes a preset concentration. A method for controlling the atmosphere inside a non-oxidizing heat treatment furnace.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3953091A JPH04259324A (en) | 1991-02-08 | 1991-02-08 | Method for controlling atmosphere in continuous type non-oxidizing heat treatment furnace |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3953091A JPH04259324A (en) | 1991-02-08 | 1991-02-08 | Method for controlling atmosphere in continuous type non-oxidizing heat treatment furnace |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH04259324A true JPH04259324A (en) | 1992-09-14 |
Family
ID=12555602
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3953091A Pending JPH04259324A (en) | 1991-02-08 | 1991-02-08 | Method for controlling atmosphere in continuous type non-oxidizing heat treatment furnace |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH04259324A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006283116A (en) * | 2005-03-31 | 2006-10-19 | Dowa Mining Co Ltd | Method and device for heat treatment |
| JP2011042878A (en) * | 2010-10-06 | 2011-03-03 | Dowa Holdings Co Ltd | Method and device for heat treatment |
| JP2015117396A (en) * | 2013-12-17 | 2015-06-25 | 大同プラント工業株式会社 | Continuous-type steel pipe annealing furnace atmosphere control method |
| CN112609056A (en) * | 2021-01-07 | 2021-04-06 | 湖北中冶窑炉有限公司 | Decarburization-preventing steel through type heat treatment system and heat treatment method |
-
1991
- 1991-02-08 JP JP3953091A patent/JPH04259324A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006283116A (en) * | 2005-03-31 | 2006-10-19 | Dowa Mining Co Ltd | Method and device for heat treatment |
| JP2011042878A (en) * | 2010-10-06 | 2011-03-03 | Dowa Holdings Co Ltd | Method and device for heat treatment |
| JP2015117396A (en) * | 2013-12-17 | 2015-06-25 | 大同プラント工業株式会社 | Continuous-type steel pipe annealing furnace atmosphere control method |
| CN112609056A (en) * | 2021-01-07 | 2021-04-06 | 湖北中冶窑炉有限公司 | Decarburization-preventing steel through type heat treatment system and heat treatment method |
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