JPH11131209A - Gas carburization method - Google Patents

Gas carburization method

Info

Publication number
JPH11131209A
JPH11131209A JP9296643A JP29664397A JPH11131209A JP H11131209 A JPH11131209 A JP H11131209A JP 9296643 A JP9296643 A JP 9296643A JP 29664397 A JP29664397 A JP 29664397A JP H11131209 A JPH11131209 A JP H11131209A
Authority
JP
Japan
Prior art keywords
gas
furnace
raw material
soot
gaseous
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
Application number
JP9296643A
Other languages
Japanese (ja)
Other versions
JP3301598B2 (en
Inventor
Itaru Ishii
格 石井
Shinji Nagami
真司 永見
Shigemi Yamaguchi
繁巳 山口
Kenichi Kitamoto
健一 北本
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Dowa Holdings Co Ltd
Daihatsu Motor Co Ltd
Original Assignee
Daihatsu Motor Co Ltd
Dowa Mining Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Daihatsu Motor Co Ltd, Dowa Mining Co Ltd filed Critical Daihatsu Motor Co Ltd
Priority to JP29664397A priority Critical patent/JP3301598B2/en
Publication of JPH11131209A publication Critical patent/JPH11131209A/en
Application granted granted Critical
Publication of JP3301598B2 publication Critical patent/JP3301598B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Abstract

PROBLEM TO BE SOLVED: To dilute a gaseous raw material with the in-furnace gas of a carburization furnace rich in gaseous CO so as to decrease the amt. of the soot to be generated and to stabilize product quality by extracting the in-furnace gas and refluxing this gas to a supply path of the gaseous raw material connected to a gas inlet. SOLUTION: The gaseous raw material consisting of gaseous hydrocarbon is introduced via a gas inlet 2 into the inside 1a of the carburization furnace 1. The atmosphere gas in the carburization furnace 1 is extracted to the outside of the furnace via a sample port 6 arranged on the lateral wall of the furnace 1 by the suction force of a pump 5. This in-furnace gas is cooled with a heat exchanger 7 and is subjected to removal of impurities, such as soot, with a filter 8 and, thereafter, the gas is refluxed to the supply path 9 for supplying the gaseous raw material to the gas inlet 2. The extraction rate of the in- furnace gas is adjusted by feedback control of the pump 5 in accordance with the measured value of a flow meter 10 and the data from a sensor, etc., arranged within the furnace in such a manner that the inside of the furnace is maintained at a prescribed carbon potential.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【0001】[0001]

【発明の属する技術分野】本発明は、浸炭炉内に炭化水
素ガスを導入してCOガスを発生させ、鋼製品に浸炭処理
を施すための方法に関するものである。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for carburizing steel products by introducing hydrocarbon gas into a carburizing furnace to generate CO gas.

【0002】[0002]

【従来の技術】従来からガス浸炭方法として種々の方法
が提案されているが、そのほとんどは、メタン、プロパ
ン等の原料ガスに空気等を混合してこれを変成炉内でCO
ガスに変成し、このCOガスを浸炭炉に供給して浸炭を行
なうものである。ところが、この方法では、浸炭炉の雰
囲気中に浸炭に直接関与しないN2ガスが含まれており、
COガスのみかけ分圧が低下するため、浸炭むら等の不具
合を招きやすい。
2. Description of the Related Art Conventionally, various methods have been proposed as a gas carburizing method, but most of them are mixed with a raw material gas such as methane and propane and mixed with air or the like, and the mixed gas is converted into CO2 in a shift furnace.
It is converted into gas, and this CO gas is supplied to a carburizing furnace to perform carburizing. However, in this method, the atmosphere of the carburizing furnace contains N 2 gas that is not directly involved in carburizing,
Since the apparent partial pressure of CO gas decreases, problems such as uneven carburization are likely to occur.

【0003】この問題を解決するものとして、浸炭に直
接関与する原料ガス、すなわちメタン、プロパン等の炭
化水素ガスを直接浸炭炉内に供給し、炉内でCOガスを発
生させて浸炭処理を行なう方法がある(例えば特公平 1
-38870号公報参照)。
As a solution to this problem, a raw material gas directly involved in carburization, that is, a hydrocarbon gas such as methane or propane, is directly supplied into a carburizing furnace, and a carburizing treatment is performed by generating CO gas in the furnace. There is a method (for example, Tokuhei 1
-38870).

【0004】この方法であれば、炉内の雰囲気からN2
スを除去できるので上記不具合を解消することができ
る。その一方で、ガスインレットの内径部に多量の煤が
付着堆積しやすい。そこで、従来では、図2に示すよう
に、原料ガスの供給路(19)とは別に炭酸ガスの供給路
(20)を設置し、定期的(数分〜数十分毎)に電磁バル
ブ(23)を開いて(この時、原料ガスの供給路(19)の
コントロールバルブ(13)を閉じる)、高圧(例えば5
kg/cm2)の炭酸ガスをガスインレット(12)に圧送し、
付着した煤を飛散除去するようにしている。
[0004] According to this method, since the N 2 gas can be removed from the atmosphere in the furnace, the above problem can be solved. On the other hand, a large amount of soot tends to adhere and deposit on the inner diameter of the gas inlet. Therefore, conventionally, as shown in FIG. 2, a supply path (20) of carbon dioxide gas is provided separately from a supply path (19) of the raw material gas, and the electromagnetic valve ( 23) (at this time, the control valve (13) of the source gas supply path (19) is closed),
kg / cm 2 ) of carbon dioxide gas into the gas inlet (12)
The attached soot is scattered and removed.

【0005】[0005]

【発明が解決しようとする課題】しかしながら、煤を飛
散させた後の炭酸ガスは浸炭炉(11)に供給されるた
め、頻繁に煤の除去を行なうと、多量の炭酸ガスが炉内
(11 a) に入り、その結果として浸炭能(カーボンポテ
ンシャル)が低下して品質の不安定化を招く。この場
合、カーボンポテンシャルを回復しようとすれば、多量
の原料ガスを炉内に供給しなければならず、煤の発生量
が一段と増加する。これは、煤の除去作業をさらに頻繁
に行なわなければならないことを意味し、メンテナンス
コストの高騰を招く。
However, since the carbon dioxide gas after the soot is scattered is supplied to the carburizing furnace (11), if the soot is removed frequently, a large amount of the carbon dioxide gas in the furnace is generated.
(11a), and as a result, the carburizing ability (carbon potential) is reduced, leading to unstable quality. In this case, in order to recover the carbon potential, a large amount of source gas must be supplied into the furnace, and the amount of soot generated further increases. This means that the soot removal operation has to be performed more frequently, which causes an increase in maintenance costs.

【0006】そこで本発明は、煤の発生量を減らして製
品品質の安定化を図ることのできるガス浸炭方法の提供
を目的とする。
Accordingly, an object of the present invention is to provide a gas carburizing method capable of stabilizing product quality by reducing the amount of generated soot.

【0007】[0007]

【課題を解決するための手段】上記目的を達成すべく、
本発明では、浸炭炉内にガスインレットを介して炭化水
素ガスを含む原料ガスを導入し、浸炭炉内でCOガスを発
生させて鋼製品に浸炭処理を施すに際し、炉内ガスを抽
出して、これをガスインレットに接続した原料ガスの供
給路に還流させることとした。
In order to achieve the above object,
In the present invention, a raw material gas containing a hydrocarbon gas is introduced into a carburizing furnace through a gas inlet, and when performing a carburizing treatment on a steel product by generating a CO gas in the carburizing furnace, the furnace gas is extracted. This was returned to the source gas supply path connected to the gas inlet.

【0008】このように炉内ガスの一部を原料ガスに還
流させることにより、煤発生の原因である原料ガスがCO
ガスに富む炉内ガスで希釈されるため、炉内のCO分圧
(カーボンポテンシャル)を低下させることなく煤の発
生量を減らすことができる。また、原料ガスの使用量も
減らすこともできる。
[0008] By recirculating a part of the gas in the furnace to the source gas in this manner, the source gas causing soot generation becomes CO2.
Since the gas is diluted with the furnace-rich gas, the amount of soot generated can be reduced without lowering the CO partial pressure (carbon potential) in the furnace. Also, the amount of source gas used can be reduced.

【0009】[0009]

【発明の実施の形態】図1に本発明の一実施形態を示
す。図示のように浸炭炉(1)の内部(1a)には、炉
(1)の上部壁に配置したガスインレット(2)を介し
て炭化水素ガス(例えばブタンガス:C4H10 )からなる
原料ガスが一定圧(例えば0.5 kg/cm2)で導入される。
原料ガスの導入量は、コントロールバルブ(3)で調節
される。
FIG. 1 shows an embodiment of the present invention. As shown in the figure, inside a carburizing furnace (1), a raw material composed of a hydrocarbon gas (for example, butane gas: C 4 H 10 ) is provided through a gas inlet (2) arranged on an upper wall of the furnace (1). Gas is introduced at a constant pressure (eg, 0.5 kg / cm 2 ).
The introduction amount of the source gas is adjusted by the control valve (3).

【0010】浸炭炉(1)内の雰囲気ガスは、ポンプ
(5)の吸引力により、炉(1)の側方壁に配置したサ
ンプルポート(6)を介して炉外に抽出される。そし
て、この炉内ガスは熱交換器(7)で冷却し、フィルタ
(8)で煤等の不純物を除去した上で、原料ガスをガス
インレット(2)に供給する供給路(9)に還流され
る。(10)は炉内ガスの流量計である。炉内ガスの抽出
量は、流量計(10)の計測値および炉内に配置された図
示しないセンサ( CO2センサ等)からのデータに基づ
き、ポンプ(5)をフィードバック制御することによ
り、炉内が所定のカーボンポテンシャルに維持されるよ
う調節される。
Atmospheric gas in the carburizing furnace (1) is extracted outside the furnace by a suction force of a pump (5) through a sample port (6) arranged on a side wall of the furnace (1). The gas in the furnace is cooled by a heat exchanger (7), and impurities such as soot are removed by a filter (8). Then, the gas is returned to a supply path (9) for supplying a raw material gas to a gas inlet (2). Is done. (10) is a furnace gas flow meter. The amount of gas extracted in the furnace is determined by performing feedback control of the pump (5) based on the measurement value of the flow meter (10) and data from a sensor (not shown) (CO 2 sensor, etc.) arranged in the furnace. Is adjusted so as to maintain a predetermined carbon potential.

【0011】このように、本発明では、炉内ガスの一部
を原料ガスの供給路(9)に還流させ、原料ガスを炉内
ガスで希釈してから浸炭炉(1)に供給している。従っ
て、原料ガス中の炭化水素ガスの濃度を相対的に低下さ
せることができ、煤の発生を抑えてガスインレット
(2)での煤の付着量を少なくすることができる。ま
た、煤除去用の炭酸ガス等も不要もしくはその使用量を
少なくできるので、構造を簡素化して低コスト化を図る
ことができる。原料ガスを希釈する場合には、カーボン
ポテンシャルの低下が懸念されるが、一般に炉内ガスは
COがその主成分であるから、この炉内ガスで希釈しても
カーボンポテンシャルの低下はほとんど生じず、品質を
安定化させることができる。
As described above, in the present invention, a part of the furnace gas is returned to the raw material gas supply path (9), and the raw material gas is diluted with the furnace gas and then supplied to the carburizing furnace (1). I have. Therefore, the concentration of the hydrocarbon gas in the raw material gas can be relatively reduced, soot generation can be suppressed, and the amount of soot attached to the gas inlet (2) can be reduced. Further, since carbon dioxide gas for removing soot is not required or its use amount can be reduced, the structure can be simplified and the cost can be reduced. When diluting the source gas, there is a concern that the carbon potential will decrease.
Since CO is the main component, even if diluted with this furnace gas, the carbon potential hardly decreases, and the quality can be stabilized.

【0012】なお、本実施形態では炭化水素ガスとして
ブタンガスを使用しているが、メタン、プロパン等の他
の炭化水素系ガスも使用可能である。原料ガスには、炭
化水素ガスだけでなく、CO2 やO2、あるいは空気等の炭
化水素ガスの変成に必要な適宜のガスを含ませることが
できる。
In this embodiment, butane gas is used as the hydrocarbon gas, but other hydrocarbon gases such as methane and propane can be used. The raw material gas may include not only hydrocarbon gas but also CO 2 , O 2 , or an appropriate gas required for conversion of hydrocarbon gas such as air.

【0013】[0013]

【発明の効果】このように本発明によれば、炉内のカー
ボンポテンシャルを低下させることなく煤の発生量を減
らすことができるので、製品品質の安定化を図りつつ炭
化水素ガスや炭酸ガス等の煤除去用ガスの使用量を削減
でき、メンテナンスコストや稼動コストの削減に多大な
効果が奏される。
As described above, according to the present invention, it is possible to reduce the amount of soot generated without lowering the carbon potential in the furnace. The amount of soot removal gas used can be reduced, and a great effect is achieved in reducing maintenance costs and operating costs.

【図面の簡単な説明】[Brief description of the drawings]

【図1】本発明にかかるガス浸炭方法を実施するための
装置の断面図である。
FIG. 1 is a cross-sectional view of an apparatus for performing a gas carburizing method according to the present invention.

【図2】従来装置の断面図である。FIG. 2 is a sectional view of a conventional device.

【符号の説明】[Explanation of symbols]

1 浸炭炉 2 ガスインレット 9 供給路 1 Carburizing furnace 2 Gas inlet 9 Supply path

───────────────────────────────────────────────────── フロントページの続き (72)発明者 山口 繁巳 東京都千代田区丸の内1丁目8番2号 同 和鉱業株式会社内 (72)発明者 北本 健一 東京都千代田区丸の内1丁目8番2号 同 和鉱業株式会社内 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Shigemi Yamaguchi 1-8-2 Marunouchi, Chiyoda-ku, Tokyo Dowa Mining Co., Ltd. (72) Inventor Kenichi Kitamoto 1-8-2 Marunouchi, Chiyoda-ku, Tokyo Dowa Mining Co., Ltd.

Claims (1)

【特許請求の範囲】[Claims] 【請求項1】 浸炭炉内にガスインレットを介して炭化
水素ガスを含む原料ガスを導入し、浸炭炉内でCOガスを
発生させて鋼製品に浸炭処理を施すに際し、炉内ガスを
抽出して、これをガスインレットに接続した原料ガスの
供給路に還流させることを特徴とするガス浸炭方法。
1. A raw material gas containing a hydrocarbon gas is introduced into a carburizing furnace through a gas inlet, and CO gas is generated in the carburizing furnace to perform carburizing treatment on a steel product. And recirculating the gas to a gas supply path connected to the gas inlet.
JP29664397A 1997-10-29 1997-10-29 Gas carburizing method Expired - Fee Related JP3301598B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP29664397A JP3301598B2 (en) 1997-10-29 1997-10-29 Gas carburizing method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP29664397A JP3301598B2 (en) 1997-10-29 1997-10-29 Gas carburizing method

Publications (2)

Publication Number Publication Date
JPH11131209A true JPH11131209A (en) 1999-05-18
JP3301598B2 JP3301598B2 (en) 2002-07-15

Family

ID=17836200

Family Applications (1)

Application Number Title Priority Date Filing Date
JP29664397A Expired - Fee Related JP3301598B2 (en) 1997-10-29 1997-10-29 Gas carburizing method

Country Status (1)

Country Link
JP (1) JP3301598B2 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008267778A (en) * 2007-03-23 2008-11-06 Dowa Thermotech Kk Heat treatment system
US20090253090A1 (en) * 2008-04-04 2009-10-08 Hyundai Motor Company System for controlling atmosphere gas inside furnace

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5677321A (en) * 1979-11-28 1981-06-25 Kanto Yakin Kogyo Kk Energy saving type atmosphere furnace for metal heat treatment
JPS61159567A (en) * 1984-12-31 1986-07-19 Tokyo Netsu Shiyori Kogyo Kk Gas carburizing method
JPS6345358A (en) * 1986-08-12 1988-02-26 Mitsubishi Motors Corp Gas carburizing method

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5677321A (en) * 1979-11-28 1981-06-25 Kanto Yakin Kogyo Kk Energy saving type atmosphere furnace for metal heat treatment
JPS61159567A (en) * 1984-12-31 1986-07-19 Tokyo Netsu Shiyori Kogyo Kk Gas carburizing method
JPS6345358A (en) * 1986-08-12 1988-02-26 Mitsubishi Motors Corp Gas carburizing method

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008267778A (en) * 2007-03-23 2008-11-06 Dowa Thermotech Kk Heat treatment system
US20090253090A1 (en) * 2008-04-04 2009-10-08 Hyundai Motor Company System for controlling atmosphere gas inside furnace
US8157561B2 (en) * 2008-04-04 2012-04-17 Hyundai Motor Company System for controlling atmosphere gas inside furnace

Also Published As

Publication number Publication date
JP3301598B2 (en) 2002-07-15

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