JP5629436B2 - Surface hardening processing apparatus and surface hardening processing method - Google Patents

Surface hardening processing apparatus and surface hardening processing method Download PDF

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JP5629436B2
JP5629436B2 JP2009170345A JP2009170345A JP5629436B2 JP 5629436 B2 JP5629436 B2 JP 5629436B2 JP 2009170345 A JP2009170345 A JP 2009170345A JP 2009170345 A JP2009170345 A JP 2009170345A JP 5629436 B2 JP5629436 B2 JP 5629436B2
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河田　一喜
一喜 河田
徹 木立
徹 木立
関谷　慶之
慶之 関谷
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オリエンタルエンヂニアリング株式会社
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本発明は、例えば、窒化、軟窒化、浸炭、浸炭窒化等、金属製の被処理品に対する表面硬化処理を行う、表面硬化処理装置及び表面硬化処理方法に関する。   The present invention relates to a surface hardening processing apparatus and a surface hardening processing method for performing a surface hardening process on a metal workpiece such as nitriding, soft nitriding, carburizing, carbonitriding and the like.

従来から、金属製の被処理品、特に、鋼部品や金型に対する表面硬化処理として、窒化処理や軟窒化処理が適用されている。この窒化処理や軟窒化処理は、後述する浸炭処理や浸炭窒化処理と比較して、処理温度が低く、また、歪みの少ない処理法である。
このような窒化処理や軟窒化処理の方法としては、ガス法、塩浴法、プラズマ法等がある。そして、これらの方法の中では、ガス法が、品質、環境性、量産性等を考慮した場合に、総合的に優れている。 Conventionally, nitriding treatment and soft nitriding treatment have been applied as surface hardening treatment for metal workpieces, particularly steel parts and molds. This nitriding treatment or soft nitriding treatment is a treatment method having a lower treatment temperature and less distortion compared to a carburizing treatment and a carbonitriding treatment described later.
Examples of such nitriding and soft nitriding methods include a gas method, a salt bath method, and a plasma method. Among these methods, the gas method is generally excellent when quality, environmental performance, mass productivity, and the like are taken into consideration.

ところで、ガス法による窒化処理（ガス窒化処理）は、被処理品に対し、窒素のみを浸透拡散させて、表面を硬化させるプロセスを有する。また、ガス窒化処理では、アンモニアガス、アンモニアガスと窒素ガスとの混合ガス、アンモニアガスとアンモニア分解ガス（７５％Ｈ２，２５％Ｎ２）との混合ガスを処理炉内へ導入して、表面硬化処理を行う。
一方、ガス法による軟窒化処理（ガス軟窒化処理）は、被処理品に対し、窒素とともに炭素を副次的に浸透拡散させて、表面を硬化させるプロセスを有する。また、ガス軟窒化処理では、アンモニアガスとＲＸガス（ＣＯ，Ｈ２，Ｎ２を主成分とする吸熱型変成ガス）との混合ガス、アンモニアガスと窒素ガスとＣＯ２との混合ガス等、複数種類の炉内導入ガスを混合した混合ガスを処理炉内へ導入して、表面硬化処理を行う。 By the way, the nitriding treatment (gas nitriding treatment) by the gas method has a process of hardening the surface by permeating and diffusing only nitrogen into the article to be treated. In the gas nitriding treatment, ammonia gas, a mixed gas of ammonia gas and nitrogen gas, a mixed gas of ammonia gas and ammonia decomposition gas (75% H 2 , 25% N 2 ) is introduced into the processing furnace, Surface hardening treatment is performed.
On the other hand, the soft nitriding treatment (gas soft nitriding treatment) by the gas method has a process of hardening the surface by secondarily penetrating and diffusing carbon together with nitrogen to the article to be treated. In the gas soft nitriding treatment, a mixed gas of ammonia gas and RX gas (an endothermic modified gas mainly composed of CO, H 2 , and N 2 ), a mixed gas of ammonia gas, nitrogen gas, and CO 2 , etc. A mixed gas obtained by mixing a plurality of types of in-furnace gases is introduced into the processing furnace, and surface hardening treatment is performed.

以上のようなガス窒化処理及びガス軟窒化処理では、内部に被処理品を配置した処理炉内の雰囲気を管理するために、例えば、非特許文献１に記載されているような測定方法を用いて、炉内ガスのアンモニア濃度や水素濃度を測定する場合がある。
具体的に、非特許文献１には、処理炉内に存在している炉内ガスのアンモニア濃度を測定する方法として、手動ガラス管アンモニア分析計を用いて、不連続に炉内ガスのアンモニア濃度を測定する方法と、赤外線アンモニア分析計を用いて、連続的に炉内ガスのアンモニア濃度を測定する方法が記載されている。 In the gas nitriding process and the gas soft nitriding process as described above, for example, a measurement method described in Non-Patent Document 1 is used to manage the atmosphere in the processing furnace in which the article to be processed is arranged. In some cases, the ammonia concentration or hydrogen concentration of the gas in the furnace is measured.
Specifically, in Non-Patent Document 1, as a method of measuring the ammonia concentration of the in-furnace gas existing in the processing furnace, the ammonia concentration of the in-furnace gas is discontinuously using a manual glass tube ammonia analyzer. And a method for continuously measuring the ammonia concentration of the in-furnace gas using an infrared ammonia analyzer.

また、非特許文献１には、炉内ガスの水素濃度を測定する方法として、炉内ガスの熱伝導度を利用した熱伝導度センサを用いて、連続的に炉内ガスの水素濃度を測定する方法が記載されている。なお、上記の熱伝導度センサは、処理炉の炉体に直接装着することが可能な構成であり、炉内ガスの熱伝導度に基づいて、炉内ガスの水素濃度を検出可能な構成である。
また、被処理品に対する表面硬化処理としては、上述した窒化処理や軟窒化処理の他に、浸炭処理や浸炭窒化処理がある。浸炭処理や浸炭窒化処理は、窒化処理や軟窒化処理と比較して、処理温度が高く、また、歪みが大きいものの、深い硬化層を形成可能な処理法である。 Further, Non-Patent Document 1 continuously measures the hydrogen concentration of the in-furnace gas using a thermal conductivity sensor using the thermal conductivity of the in-furnace gas as a method for measuring the hydrogen concentration of the in-furnace gas. How to do is described. The above thermal conductivity sensor can be directly attached to the furnace body of the processing furnace, and can detect the hydrogen concentration of the in-furnace gas based on the thermal conductivity of the in-furnace gas. is there.
In addition to the above-described nitriding treatment and soft nitriding treatment, there are carburizing treatment and carbonitriding treatment as the surface hardening treatment for the article to be treated. The carburizing treatment and the carbonitriding treatment are treatment methods that can form a deep hardened layer although the treatment temperature is higher and the strain is larger than the nitriding treatment and the soft nitriding treatment.

このような浸炭処理や浸炭窒化処理の方法としては、ガス法、塩浴法、プラズマ法、真空法（減圧法）等がある。そして、これらの方法の中では、真空法が、他の方法と比較して、環境性が良好である、浸炭速度が速い、表面異常層が発生しない等の利点を有している。
ところで、真空法による浸炭処理（真空浸炭処理）は、被処理品に対し、炭素のみを浸透拡散させて、表面を硬化させるプロセスを有する。また、真空浸炭処理では、アセチレンガス、プロパンガス、エチレンガス等の炭化水素を、単独または複数同時に処理炉内に導入する場合や、炭化水素と窒素ガスとを混合した混合ガスを処理炉内へ導入して、表面硬化処理を行う。 Examples of such carburizing and carbonitriding methods include a gas method, a salt bath method, a plasma method, and a vacuum method (decompression method). Among these methods, the vacuum method has advantages such as better environmental properties, faster carburization rate, and no generation of an abnormal surface layer compared to other methods.
By the way, the carburizing process (vacuum carburizing process) by the vacuum method has a process in which only the carbon is permeated and diffused into the object to be processed to harden the surface. In the case of vacuum carburizing, hydrocarbons such as acetylene gas, propane gas, and ethylene gas are introduced into the processing furnace alone or in combination, or a mixed gas in which hydrocarbon and nitrogen gas are mixed into the processing furnace. Introduce and perform surface hardening treatment.

一方、真空法による浸炭窒化処理（真空浸炭窒化処理）は、被処理品に対し、炭素とともに窒素を副次的に浸透拡散させて、表面を硬化させるプロセスを有する。そして、真空浸炭窒化処理では、真空浸炭を行った後に、アンモニアガスを単独で、または、アンモニアガスと窒素ガスを混合した混合ガスを処理炉内へ導入して、表面硬化処理を行う。
以上のような浸炭処理や浸炭窒化処理では、処理炉内の雰囲気を管理するために、例えば、非特許文献２及び３に記載されているような熱伝導度センサを用いて、炉内ガスの水素濃度を測定する場合がある。なお、非特許文献２及び３に記載されている熱伝導度センサは、非特許文献１に記載されている熱伝導度センサと同様、炉内ガスの熱伝導度に基づいて、炉内ガスの水素濃度を検出するものである。 On the other hand, carbonitriding treatment (vacuum carbonitriding treatment) by a vacuum method has a process of hardening the surface by secondarily penetrating and diffusing nitrogen together with carbon into a workpiece. In the vacuum carbonitriding process, after performing the carburizing process, the surface hardening process is performed by introducing ammonia gas alone or a mixed gas obtained by mixing ammonia gas and nitrogen gas into the processing furnace.
In the carburizing process and the carbonitriding process as described above, in order to manage the atmosphere in the processing furnace, for example, using a thermal conductivity sensor as described in Non-Patent Documents 2 and 3, The hydrogen concentration may be measured. Note that the thermal conductivity sensors described in Non-Patent Documents 2 and 3 are similar to the thermal conductivity sensor described in Non-Patent Document 1, based on the thermal conductivity of the furnace gas. It detects the hydrogen concentration.

河田一喜、「窒化ポテンシャル制御システム付きガス軟窒化炉」、熱処理、４９巻２号、２００９、Ｐ．６４〜６８Kawada, K., “Gas soft nitriding furnace with nitriding potential control system”, Heat Treatment, Vol. 49, No. 2, 2009, p. 64-68 河田一喜、「浸炭処理および窒化処理」、機械設計、５１巻７号、２００７、Ｐ．５４〜５９Kazuki Kawada, “Carburizing and Nitriding”, Mechanical Design, Vol. 51, No. 7, 2007, 54-59 河田一喜、「雰囲気制御付き真空浸炭炉の実用化」、熱処理、４４巻５号、２００４、Ｐ．２８９〜２９５Kazuki Kawada, “Practical application of vacuum carburizing furnace with atmosphere control”, Heat treatment, Vol. 44, No. 5, 2004, P.A. 289-295

特許文献１に記載されている手動ガラス管アンモニア分析計は、手動操作により測定を行う構成であるため、炉内ガスのアンモニア濃度を連続的に測定することが不可能であり、処理炉内の雰囲気に対する、連続自動制御に適用できない。
また、特許文献１に記載されている赤外線アンモニア分析計は、炉内ガスのアンモニア濃度を連続的に測定可能であるため、処理炉内の雰囲気に対する連続自動制御に適用することは可能であるが、炉内ガスを、サンプリングポンプにより赤外線アンモニア分析計に導入する必要がある。このため、ガス軟窒化処理においては、炭酸アンモニウムの析出により、サンプリング経路の詰りが発生しやすく、定期的にフィルター清掃等のメンテナンスを行う必要があるため、表面硬化処理の作業効率が低下するという問題が発生するおそれがある。 Since the manual glass tube ammonia analyzer described in Patent Document 1 is configured to perform measurement by manual operation, it is impossible to continuously measure the ammonia concentration in the furnace gas. It cannot be applied to continuous automatic control for the atmosphere.
Moreover, since the infrared ammonia analyzer described in Patent Document 1 can continuously measure the ammonia concentration in the furnace gas, it can be applied to continuous automatic control over the atmosphere in the processing furnace. It is necessary to introduce the gas in the furnace into the infrared ammonia analyzer by a sampling pump. For this reason, in gas soft nitriding treatment, clogging of the sampling path is likely to occur due to precipitation of ammonium carbonate, and it is necessary to periodically perform maintenance such as filter cleaning, so that the work efficiency of the surface hardening treatment is reduced. Problems may occur.

また、特許文献１に記載されている赤外線アンモニア分析計は、手動ガラス管アンモニア分析計や熱伝導度センサと比較して高価であるため、コスト面等から採用が困難であるという問題がある。
これに対し、特許文献１から３に記載されている熱伝導度センサは、赤外線アンモニア分析計と異なり、低価格であり、且つ、処理炉の炉体に直接装着することが可能であり、また、炉内ガスの水素濃度を連続的に測定可能であるため、処理炉内の雰囲気に対する連続自動制御に適用可能である。 Moreover, since the infrared ammonia analyzer described in Patent Document 1 is more expensive than a manual glass tube ammonia analyzer or a thermal conductivity sensor, there is a problem that it is difficult to adopt from the viewpoint of cost.
On the other hand, unlike the infrared ammonia analyzer, the thermal conductivity sensors described in Patent Documents 1 to 3 are inexpensive and can be directly attached to the furnace body of the processing furnace. Since the hydrogen concentration of the gas in the furnace can be continuously measured, it can be applied to continuous automatic control for the atmosphere in the processing furnace.

したがって、上述したガス窒化処理等、複数種類の炉内導入ガスを混合した混合ガスを処理炉内に導入して行う表面硬化処理では、特許文献１から３に記載されているような熱伝導度センサを用いて、処理炉内の雰囲気制御を行うことが、コスト面等の観点から好適である。
また、熱伝導度センサは、赤外線アンモニア分析計と異なり、処理炉の炉体へ直接装着することが可能であり、さらに、処理炉内の水素濃度を連続的に測定可能であるため、処理炉内の雰囲気に対する連続自動制御に適用可能である。 Therefore, in the surface hardening treatment performed by introducing a mixed gas obtained by mixing a plurality of types of in-furnace introduction gases into the treatment furnace, such as the above-described gas nitriding treatment, the thermal conductivity as described in Patent Documents 1 to 3 From the viewpoint of cost and the like, it is preferable to control the atmosphere in the processing furnace using a sensor.
Also, unlike the infrared ammonia analyzer, the thermal conductivity sensor can be directly attached to the furnace body of the processing furnace, and further, the hydrogen concentration in the processing furnace can be continuously measured. It can be applied to continuous automatic control for the atmosphere inside.

しかしながら、熱伝導度センサには、以下に示すような問題点がある。
熱伝導度センサを、単に炉体へ装着しただけでは、炉内ガスが熱伝導度センサのセンサ部に流入するまでに時間を要するという問題が発生するおそれがある。また、熱伝導度センサの装着位置によっては、炉内ガスの偏った成分のみがセンサ部に流入し、炉内ガス全体の水素濃度を正確に反映することが困難となるという問題が発生するおそれがある。 However, the thermal conductivity sensor has the following problems.
If the thermal conductivity sensor is simply attached to the furnace body, there may be a problem that it takes time until the in-furnace gas flows into the sensor portion of the thermal conductivity sensor. In addition, depending on the mounting position of the thermal conductivity sensor, only a biased component of the furnace gas flows into the sensor unit, and it may be difficult to accurately reflect the hydrogen concentration of the entire furnace gas. There is.

また、熱伝導度センサを常に炉体へ装着している状態では、実際に被処理品を量産処理する場合、被処理品が処理炉内に配置し、昇温中において初期に発生する、被処理品に付着していた油分や汚れがガス化してセンサ部を汚染し、熱伝導度センサの精度維持が、早期に困難となるという問題が発生するおそれがある。
また、ガス軟窒化処理においては、センサ部と炉体とを連通する配管内に、炭酸アンモニウムの析出が発生するという問題が発生するおそれがある。また、処理炉内において塩化水素が発生するようなプロセスを有する場合、センサ部や配管内に、塩化アンモニウムの析出が発生することにより、熱伝導度センサの精度維持が困難となるという問題が発生するおそれがある。 In addition, in the state where the thermal conductivity sensor is always attached to the furnace body, when the product to be processed is actually mass-produced, the product to be processed is placed in the processing furnace and is initially generated during the temperature rise. There is a risk that the oil or dirt adhering to the processed product will be gasified to contaminate the sensor unit, and it may become difficult to maintain the accuracy of the thermal conductivity sensor at an early stage.
Further, in the gas soft nitriding treatment, there may be a problem that ammonium carbonate is precipitated in a pipe communicating the sensor unit and the furnace body. In addition, when there is a process that generates hydrogen chloride in the processing furnace, precipitation of ammonium chloride occurs in the sensor section and piping, which makes it difficult to maintain the accuracy of the thermal conductivity sensor. There is a risk.

また、真空浸炭や浸炭窒化処理においても、煤やタールがセンサ部に付着して、熱伝導度センサの精度維持が困難となるという問題が発生するおそれがある。
しかしながら、従来では、熱伝導度センサの精度を、長期間安定して維持することが可能な手段や対策が、開示されていない。
また、従来では、熱伝導度センサを用いた処理炉内の雰囲気制御に関して、具体的な制御方法が開示されていない。 Also, in vacuum carburizing and carbonitriding, there is a possibility that soot and tar adhere to the sensor part and it becomes difficult to maintain the accuracy of the thermal conductivity sensor.
However, conventionally, no means or countermeasure that can stably maintain the accuracy of the thermal conductivity sensor for a long period of time has been disclosed.
Conventionally, no specific control method has been disclosed for controlling the atmosphere in the processing furnace using the thermal conductivity sensor.

このため、混合ガスを用いる表面硬化処理では、複数種類の炉内導入ガスの消費量を一定の比率とする等、処理炉内の雰囲気を参照せずに表面硬化処理を行うこととなる。これにより、炉内導入ガスの消費量が、表面硬化処理に適切な量よりも増加して、表面硬化処理に要するランニングコストが増加するという問題が発生するおそれがある。また、処理炉内の雰囲気を参照せずに表面硬化処理を行うと、表面硬化処理に使用されずに処理炉内から排気される炉内ガスの量が増加して、大気中へのガス排出量が増加し、環境に悪影響を与えるという問題が発生するおそれがある。   For this reason, in the surface hardening process using a mixed gas, the surface hardening process is performed without referring to the atmosphere in the processing furnace, for example, by making the consumption of the plurality of types of in-furnace introduced gases constant. As a result, the consumption of the gas introduced into the furnace may increase more than the amount appropriate for the surface hardening process, which may cause a problem that the running cost required for the surface hardening process increases. In addition, if the surface hardening treatment is performed without referring to the atmosphere in the processing furnace, the amount of in-furnace gas exhausted from the processing furnace without being used for the surface hardening treatment increases, and the gas is discharged into the atmosphere. There is a risk that the amount will increase and the environment will be adversely affected.

本発明は、上記のような問題点に着目してなされたもので、炉内ガスの熱伝導度に基づいて処理炉内の雰囲気を検出し、この検出した雰囲気を参照して処理炉内の雰囲気を制御することが可能な、表面硬化処理装置及び表面硬化処理方法を提供することを課題とする。   The present invention has been made paying attention to the problems as described above, and detects the atmosphere in the processing furnace based on the thermal conductivity of the gas in the furnace, and refers to the detected atmosphere in the processing furnace. It is an object of the present invention to provide a surface hardening processing apparatus and a surface hardening processing method capable of controlling the atmosphere.

上記課題を解決するために、本発明のうち、請求項１に記載した発明は、処理炉内で水素を発生するガスとしてはアセチレンガスのみを含むとともに、その他のガスとして窒素ガスを含む炉内導入ガスを前記処理炉内へ導入して、前記処理炉内に配置した被処理品の表面硬化処理として真空浸炭処理を行う表面硬化処理装置であって、
前記処理炉内の炉内ガスの熱伝導度に基づいて、前記炉内ガスの水素濃度を検出する水素濃度検出手段と、
前記水素濃度検出手段が検出した水素濃度に基づいて前記アセチレンガスの炉内濃度を演算し、当該演算した炉内濃度の演算値に基づいて前記炉内ガスの組成である炉内ガス組成を演算する炉内ガス組成演算手段と、
前記炉内ガス組成演算手段が演算した炉内ガス組成と予め設定した設定炉内ガス混合比率に応じて、前記炉内ガス組成が前記設定炉内ガス混合比率となるように、前記複数種類の前記炉内導入ガスの前記処理炉内への導入量の比率である炉内導入ガス流量比率を一定値に保持した状態で前記複数種類の前記炉内導入ガスの前記処理炉内への合計導入量を制御する第一の制御と、前記炉内導入ガス流量比率が変化するように前記複数種類の炉内導入ガスの導入量を個別に制御する第二の制御と、の両者を実行可能であるとともに、同時にはいずれか一方の制御のみを選択的に行うガス導入量制御手段と、を備えることを特徴とするものである。 In order to solve the above-mentioned problems, the invention described in claim 1 of the present invention includes a furnace containing only acetylene gas as a gas for generating hydrogen in a processing furnace and nitrogen gas as another gas. and introduce the gas into the processing furnace, a surface hardening processing apparatus for performing a vacuum carburizing treatment as the surface hardening treatment of the workpieces disposed in the processing furnace,
Based on the thermal conductivity of the furnace gas in the processing furnace, hydrogen concentration detection means for detecting the hydrogen concentration of the furnace gas;
Calculate the in-furnace concentration of the acetylene gas based on the hydrogen concentration detected by the hydrogen concentration detecting means, and calculate the in-furnace gas composition which is the composition of the in-furnace gas based on the calculated value of the calculated in-furnace concentration An in-furnace gas composition calculating means,
In accordance with the in-furnace gas composition calculated by the in-furnace gas composition calculating means and the preset in-furnace gas mixing ratio, the plurality of types of the in-furnace gas composition become the set in-furnace gas mixing ratio. total Previous Symbol the processing furnace of a plurality of types of the furnace gas introduced while holding the furnace introduced gas flow ratio is the ratio of the introduction amount into the processing furnace of the furnace gas introduced to a constant value Both the first control for controlling the introduction amount and the second control for individually controlling the introduction amounts of the plurality of types of in-furnace introduction gases so that the in-furnace introduction gas flow rate ratio can be changed. And a gas introduction amount control means for selectively performing only one of the controls at the same time.

本発明によると、水素濃度検出手段が、炉内ガスの熱伝導度に基づいて検出した炉内ガスの水素濃度に応じて、処理炉内で水素を発生する炉内導入ガスであるアセチレンガスの炉内濃度を演算して求める。そして、この演算値に基づいて、炉内ガス組成演算手段が、炉内ガスの組成である炉内ガス組成を演算する。
このため、演算した炉内ガス組成と予め設定した設定炉内ガス混合比率に応じて、処理炉内の雰囲気を検出し、この検出した雰囲気を参照して、ガス導入量制御手段が、炉内ガス組成が設定炉内ガス混合比率となるように、複数種類の炉内導入ガスの導入量を制御することが可能となる。
なお、複数種類の炉内導入ガスを処理炉内へ導入する際には、例えば、複数種類の炉内導入ガスを混合した状態で処理炉内へ導入する、または、複数種類の炉内導入ガスを個別に処理炉内へ導入し、これらの導入した炉内導入ガスを処理炉内で混合する。
次に、本発明のうち、請求項２に記載した発明は、処理炉内で水素を発生するガスとしてはアンモニアガスのみを含む複数種類の炉内導入ガスを前記処理炉内へ導入して、前記処理炉内に配置した被処理品の表面硬化処理としてガス窒化処理またはガス軟窒化処理を行う表面硬化処理装置であって、
前記処理炉内の炉内ガスの熱伝導度に基づいて、前記炉内ガスの水素濃度を検出する水素濃度検出手段と、
前記水素濃度検出手段が検出した水素濃度に基づいて前記アンモニアガスの炉内濃度を演算し、当該演算した炉内濃度の演算値に基づいて前記炉内ガスの組成である炉内ガス組成を演算する炉内ガス組成演算手段と、
前記炉内ガス組成演算手段が演算した炉内ガス組成と予め設定した設定炉内ガス混合比率に応じて、前記炉内ガス組成が前記設定炉内ガス混合比率となるように、前記複数種類の前記炉内導入ガスの前記処理炉内への導入量の比率である炉内導入ガス流量比率を一定値に保持した状態で前記複数種類の前記炉内導入ガスの前記処理炉内への合計導入量を制御する第一の制御と、前記炉内導入ガス流量比率が変化するように前記複数種類の炉内導入ガスの導入量を個別に制御する第二の制御と、の両者を実行可能であるとともに、同時にはいずれか一方の制御のみを選択的に行うガス導入量制御手段と、を備えることを特徴とするものである。
本発明によると、水素濃度検出手段が、炉内ガスの熱伝導度に基づいて検出した炉内ガスの水素濃度に応じて、処理炉内で水素を発生する炉内導入ガスであるアンモニアガスの炉内濃度を演算して求める。そして、この演算値に基づいて、炉内ガス組成演算手段が、炉内ガスの組成である炉内ガス組成を演算する。
このため、演算した炉内ガス組成と予め設定した設定炉内ガス混合比率に応じて、処理炉内の雰囲気を検出し、この検出した雰囲気を参照して、ガス導入量制御手段が、炉内ガス組成が設定炉内ガス混合比率となるように、複数種類の炉内導入ガスの導入量を制御することが可能となる。 According to the present invention, the hydrogen concentration detection means detects the acetylene gas that is an in-furnace introduced gas that generates hydrogen in the processing furnace according to the hydrogen concentration of the in-furnace gas detected based on the thermal conductivity of the in-furnace gas. Calculate the furnace concentration. And based on this calculated value, the in-furnace gas composition calculating means calculates the in-furnace gas composition which is the composition of the in-furnace gas.
For this reason, the atmosphere in the processing furnace is detected according to the calculated in-furnace gas composition and a preset set-in-furnace gas mixing ratio, and the gas introduction amount control means It is possible to control the introduction amounts of a plurality of types of in-furnace introduced gases so that the gas composition becomes the set in-furnace gas mixing ratio.
In addition, when introducing a plurality of types of in-furnace introduction gases into the processing furnace, for example, introducing a plurality of types of in-furnace introduction gases into the processing furnace in a mixed state or a plurality of types of in-furnace introduction gases. Are individually introduced into the processing furnace, and the introduced gas in the furnace is mixed in the processing furnace.
Next, among the present inventions, the invention described in claim 2 introduces a plurality of types of in-furnace introduction gases containing only ammonia gas as gas for generating hydrogen in the treatment furnace, A surface hardening treatment apparatus for performing gas nitriding treatment or gas soft nitriding treatment as a surface hardening treatment of an article to be processed disposed in the processing furnace,
Based on the thermal conductivity of the furnace gas in the processing furnace, hydrogen concentration detection means for detecting the hydrogen concentration of the furnace gas;
The in-furnace concentration of the ammonia gas is calculated based on the hydrogen concentration detected by the hydrogen concentration detection means, and the in-furnace gas composition that is the composition of the in-furnace gas is calculated based on the calculated value of the calculated in-furnace concentration. An in-furnace gas composition calculating means,
In accordance with the in-furnace gas composition calculated by the in-furnace gas composition calculating means and the preset in-furnace gas mixing ratio, the plurality of types of the in-furnace gas composition become the set in-furnace gas mixing ratio. total Previous Symbol the processing furnace of a plurality of types of the furnace gas introduced while holding the furnace introduced gas flow ratio is the ratio of the introduction amount into the processing furnace of the furnace gas introduced to a constant value Both the first control for controlling the introduction amount and the second control for individually controlling the introduction amounts of the plurality of types of in-furnace introduction gases so that the in-furnace introduction gas flow rate ratio can be changed. And a gas introduction amount control means for selectively performing only one of the controls at the same time.
According to the present invention, the hydrogen concentration detecting means detects the ammonia gas that is an in-furnace introduced gas that generates hydrogen in the processing furnace according to the hydrogen concentration of the in-furnace gas detected based on the thermal conductivity of the in-furnace gas. Calculate the furnace concentration. And based on this calculated value, the in-furnace gas composition calculating means calculates the in-furnace gas composition which is the composition of the in-furnace gas.
For this reason, the atmosphere in the processing furnace is detected according to the calculated in-furnace gas composition and a preset set-in-furnace gas mixing ratio, and the gas introduction amount control means It is possible to control the introduction amounts of a plurality of types of in-furnace introduced gases so that the gas composition becomes the set in-furnace gas mixing ratio.

次に、本発明のうち、請求項３に記載した発明は、請求項２に記載した発明であって、前記表面硬化処理を前記ガス軟窒化処理とし、
前記処理炉と前記水素濃度検出手段とを連通する水素濃度検出配管と、
前記水素濃度検出配管の温度を制御する配管温度制御手段と、を備え、
前記配管温度制御手段は、前記水素濃度検出配管内で前記炉内ガスが固体として析出しないように、前記アンモニアガスに応じて前記水素濃度検出配管の温度を６０〜１００℃の範囲内に制御することを特徴とするものである。 Next, of the present invention, the invention described in claim 3 is the invention described in claim 2 , wherein the surface hardening treatment is the gas soft nitriding treatment,
A hydrogen concentration detection pipe communicating the processing furnace and the hydrogen concentration detection means;
A pipe temperature control means for controlling the temperature of the hydrogen concentration detection pipe,
The pipe temperature control means controls the temperature of the hydrogen concentration detection pipe within a range of 60 to 100 ° C. according to the ammonia gas so that the furnace gas does not precipitate as a solid in the hydrogen concentration detection pipe. It is characterized by this.

本発明によると、配管温度制御手段が、ガス軟窒化処理で用いるアンモニアガスの種類に応じて、水素濃度検出配管の温度を６０〜１００℃の範囲内に制御することにより、炉内ガスが水素濃度検出配管内で固体として析出することを抑制する。
このため、塩化アンモニウムや炭酸アンモニウムが水素濃度検出配管内で析出するおそれのある表面硬化処理であるガス軟窒化処理において、水素濃度検出配管内における塩化アンモニウムや炭酸アンモニウムの析出を抑制することが可能となる。 According to the present invention, the pipe temperature control means controls the temperature of the hydrogen concentration detection pipe within the range of 60 to 100 ° C. according to the type of ammonia gas used in the gas soft nitriding process, so that the gas in the furnace is hydrogen. Suppresses precipitation as a solid in the concentration detection pipe.
For this reason , it is possible to suppress ammonium chloride and ammonium carbonate precipitation in the hydrogen concentration detection pipe in the gas soft nitriding process, which is a surface hardening process that may cause ammonium chloride and ammonium carbonate to precipitate in the hydrogen concentration detection pipe. It becomes.

なお、配管温度制御手段が水素濃度検出配管の温度を制御する際には、表面硬化処理が、処理炉内で塩化水素ガスが発生するようなガス窒化処理である場合は、水素濃度検出配管の温度を３４０〜４５０℃の範囲内に制御することが好適である。また、表面硬化処理がガス軟窒化処理である場合は、水素濃度検出配管の温度を６０〜１００℃の範囲内に制御することが好適である。   When the pipe temperature control means controls the temperature of the hydrogen concentration detection pipe, if the surface hardening process is a gas nitriding process that generates hydrogen chloride gas in the processing furnace, It is preferable to control the temperature within the range of 340 to 450 ° C. Further, when the surface hardening treatment is gas soft nitriding treatment, it is preferable to control the temperature of the hydrogen concentration detection pipe within a range of 60 to 100 ° C.

次に、本発明のうち、請求項４に記載した発明は、請求項１から３のうちいずれか１項に記載した発明であって、前記処理炉と前記水素濃度検出手段との間に介装し、前記処理炉と前記水素濃度検出手段とを連通させる連通状態と、前記処理炉と前記水素濃度検出手段との間を閉鎖する閉鎖状態と、を切換可能な開閉弁と、
前記ガス導入量制御手段の動作状態に応じて前記開閉弁を前記連通状態または前記閉鎖状態に切り換える開閉弁切換え制御手段と、を備えることを特徴とするものである。
本発明によると、開閉弁切換え制御手段が、ガス導入量制御手段の動作状態に応じて、開閉弁を連通状態または閉鎖状態に切り換える。
このため、ガス導入量制御手段が炉内導入ガスの導入量を制御していない状態において、炉内ガスが含む汚染成分が、水素濃度検出手段へ接触することを抑制可能となり、水素濃度検出手段の検出精度が低下することを、長期間に亘り抑制することが可能となる。
なお、開閉弁切換え制御手段が、開閉弁を連通状態または閉鎖状態に切り換える際には、例えば、ガス導入量制御手段が炉内導入ガスの導入量を制御している状態では、開閉弁を連通状態に切り換えて、処理炉と水素濃度検出手段とを連通させる。一方、開閉弁切換え制御手段が、ガス導入量制御手段が炉内導入ガスの導入量を制御していない状態では、開閉弁を閉鎖状態に切り換えて、処理炉と水素濃度検出手段との間を閉鎖する。
また、処理炉と水素濃度検出手段とを連通させる経路は、例えば、配管により形成する。また、この配管は、処理炉と水素濃度検出手段とを直接連通させる単線の経路であってもよく、処理炉と水素濃度検出手段との間で複数の経路に分岐する複線の経路であってもよい。 Next, among the present inventions, the invention described in claim 4 is the invention described in any one of claims 1 to 3, and is provided between the processing furnace and the hydrogen concentration detecting means. An open / close valve capable of switching between a communication state in which the processing furnace and the hydrogen concentration detection means communicate with each other and a closed state in which a space between the processing furnace and the hydrogen concentration detection means is closed;
Open / close valve switching control means for switching the open / close valve to the communication state or the closed state in accordance with the operating state of the gas introduction amount control means.
According to the present invention, the on-off valve switching control means switches the on-off valve to the communication state or the closed state according to the operating state of the gas introduction amount control means.
For this reason, when the gas introduction amount control means does not control the introduction amount of the in-furnace introduction gas, it becomes possible to suppress the contamination component contained in the furnace gas from coming into contact with the hydrogen concentration detection means. It is possible to suppress a decrease in the detection accuracy for a long period of time.
When the on-off valve switching control means switches the on-off valve to the communication state or the closed state, for example, when the gas introduction amount control means is controlling the introduction amount of the gas introduced into the furnace, the on-off valve is in communication. By switching to the state, the processing furnace and the hydrogen concentration detecting means are communicated. On the other hand, when the on-off valve switching control means is in a state where the gas introduction amount control means does not control the introduction amount of the gas introduced into the furnace, the on-off valve is switched to the closed state, and the gap between the processing furnace and the hydrogen concentration detection means is changed. Close.
Moreover, the path | route which connects a processing furnace and a hydrogen concentration detection means is formed by piping, for example. In addition, this pipe may be a single-wire path that directly connects the processing furnace and the hydrogen concentration detection means, or a double-line path that branches into a plurality of paths between the processing furnace and the hydrogen concentration detection means. Also good .

本発明によれば、炉内ガスの組成である炉内ガス組成と、予め設定した設定炉内ガス混合比率に応じて、処理炉内の雰囲気を検出し、この検出した雰囲気を参照して、処理炉内の雰囲気を制御することが可能となる。
これにより、表面硬化処理に要するランニングコストを減少させることが可能となる。また、大気中へのガス排出量を減少させることが可能となるため、環境の悪化を抑制することが可能となる。 According to the present invention, the atmosphere in the processing furnace is detected according to the gas composition in the furnace that is the composition of the gas in the furnace, and the preset furnace gas mixture ratio, and the detected atmosphere is referred to. It becomes possible to control the atmosphere in the processing furnace.
Thereby, the running cost required for the surface hardening process can be reduced. Moreover, since it becomes possible to reduce the gas discharge | emission amount to air | atmosphere, it becomes possible to suppress deterioration of an environment.

第一実施形態の表面硬化処理装置の構成を示す図である。It is a figure which shows the structure of the surface hardening processing apparatus of 1st embodiment. 第一実施形態の変形例の構成を示す図である。It is a figure which shows the structure of the modification of 1st embodiment. 第二実施形態の表面硬化処理装置の構成を示す図である。It is a figure which shows the structure of the surface hardening processing apparatus of 2nd embodiment. 比較例の表面硬化処理装置の構成を示す図である。It is a figure which shows the structure of the surface hardening processing apparatus of a comparative example.

（第一実施形態）
以下、本発明の第一実施形態（以下、「本実施形態」と記載する）について、図面を参照しつつ説明する。
（表面硬化処理の基礎的事項）
本実施形態を説明する前に、説明の前提となる事項として、被処理品の表面硬化処理に関する基礎的な事項について説明する。 (First embodiment)
Hereinafter, a first embodiment of the present invention (hereinafter referred to as “the present embodiment”) will be described with reference to the drawings.
(Basic items of surface hardening treatment)
Before explaining the present embodiment, basic matters relating to the surface hardening treatment of the article to be treated will be explained as the premise of the explanation.

以下、表面硬化処理のうち、ガス窒化処理及びガス軟窒化処理について説明する。
ガス窒化処理及びガス軟窒化処理では、被処理品を配置する処理炉（ガス窒化炉）内において、以下の式（１）で表される窒化反応が発生する。この場合、窒化反応における窒化ポテンシャルＫＮは、以下の式（２）で表される。
ＮＨ３ → （Ｎ）＋３／２Ｈ２ … （１）
ＫＮ＝ＰＮＨ３／ＰＨ２ ３／２ … （２） Hereinafter, gas nitriding treatment and gas soft nitriding treatment among the surface hardening treatments will be described.
In the gas nitriding process and the gas soft nitriding process, a nitriding reaction represented by the following formula (1) occurs in a processing furnace (gas nitriding furnace) in which an article to be processed is arranged. In this case, the nitriding potential K N in the nitriding reaction is expressed by the following formula (2).
NH 3 → (N) + 3 / 2H 2 (1)
K N = P NH3 / P H2 3/2 (2)

なお、上記の式（２）では、窒化ポテンシャルをＫＮで示し、ＮＨ３（アンモニアガス）の分圧をＰＮＨ３で示し、Ｈ２（水素ガス）の分圧をＰＨ２で示す。
ここで、窒化ポテンシャルＫＮは、公知の要素であり、上記の式（２）のように、アンモニアガスと水素ガスの分圧比率を表し、ガス窒化炉内の雰囲気が有する窒化強度または窒化能力を表す指標である。 In the above formula (2), the nitriding potential is represented by K N , the partial pressure of NH 3 (ammonia gas) is represented by P NH 3 , and the partial pressure of H 2 (hydrogen gas) is represented by P H 2 .
Here, the nitriding potential K N is a known element, and represents the partial pressure ratio of ammonia gas and hydrogen gas as in the above formula (2), and the nitriding strength or nitriding capability of the atmosphere in the gas nitriding furnace It is an index representing

次に、表面硬化処理のうち、真空浸炭処理及び真空浸炭窒化処理について説明する。
一例として、浸炭ガスとしてアセチレンガスを用いた真空浸炭処理及び真空浸炭窒化処理では、被処理品を配置する処理炉（真空浸炭炉）内において、以下の式（３）で表される浸炭反応が発生する。この場合、浸炭反応における浸炭ポテンシャルＫＣは、以下の式（４）で表される。
１／２Ｃ２Ｈ２ → （Ｃ）＋１／２Ｈ２ … （３）
ＫＣ＝ＰＣ２Ｈ２ １／２／ＰＨ２ １／２ … （４） Next, the vacuum carburizing process and the vacuum carbonitriding process among the surface hardening processes will be described.
As an example, in a vacuum carburizing process and a vacuum carbonitriding process using acetylene gas as a carburizing gas, a carburizing reaction represented by the following formula (3) is performed in a processing furnace (vacuum carburizing furnace) in which an article to be processed is placed. Occur. In this case, carburization potential K C in carburizing reaction is represented by the following formula (4).
1 / 2C 2 H 2 → (C) + 1 / 2H 2 (3)
K C = P C2H2 1/2 / P H2 1/2 (4)

なお、上記の式（４）では、浸炭ポテンシャルをＫＣで示し、Ｃ２Ｈ２（アセチレンガス）の分圧をＰＣ２Ｈ２で示し、Ｈ２（水素ガス）の分圧をＰＨ２で示す。
ここで、浸炭ポテンシャルＫＣは、公知の要素であり、上記の式（４）のように、分解前の浸炭ガス（アセチレンガス）と分解後に生成したガスとの分圧比率を表し、真空浸炭炉内の雰囲気が有する浸炭強度または浸炭能力を表す指標である。 In the above formula (4), the carburizing potential is represented by K C , the partial pressure of C 2 H 2 (acetylene gas) is represented by PC 2 H 2 , and the partial pressure of H 2 (hydrogen gas) is represented by PH 2 .
Here, the carburizing potential K C is a known element, and represents the partial pressure ratio between the carburizing gas before decomposition (acetylene gas) and the gas generated after decomposition, as shown in the above equation (4), and vacuum carburizing. It is an index representing the carburizing strength or carburizing ability of the atmosphere in the furnace.

（表面硬化処理の問題点）
次に、上述した各種の表面硬化処理に共通の問題点について説明する。
ガス窒化処理及びガス軟窒化処理のうち、ガス窒化処理において、アンモニアガスのみをガス窒化炉内に導入して表面硬化処理を行う場合、ガス窒化炉内の雰囲気を所望の窒化ポテンシャルとするためには、熱伝導度センサを用いて、ガス窒化炉内に存在している炉内ガスの水素濃度を検出する。そして、この検出した水素濃度に応じて、ガス窒化炉内へのアンモニアガスの導入量を制御する。 (Problems of surface hardening treatment)
Next, problems common to the various surface hardening processes described above will be described.
Among gas nitriding and gas soft nitriding, in the gas nitriding treatment, when surface hardening treatment is performed by introducing only ammonia gas into the gas nitriding furnace, in order to set the atmosphere in the gas nitriding furnace to a desired nitriding potential Uses a thermal conductivity sensor to detect the hydrogen concentration in the furnace gas present in the gas nitriding furnace. The amount of ammonia gas introduced into the gas nitriding furnace is controlled according to the detected hydrogen concentration.

このように、一種類の炉内導入ガスのみをガス窒化炉内に導入して表面硬化処理を行う場合は、熱伝導度センサを用いて炉内ガスの水素濃度を検出することにより、検出した水素濃度を用いた計算によって、炉内ガスのアンモニア濃度を検出することが可能となる。したがって、上記の式（２）により窒化ポテンシャルを計算して、ガス窒化炉内の雰囲気を、所望の窒化ポテンシャルに制御することが可能となる。   As described above, when only one type of furnace introduction gas is introduced into the gas nitriding furnace and the surface hardening treatment is performed, it is detected by detecting the hydrogen concentration of the furnace gas using the thermal conductivity sensor. It is possible to detect the ammonia concentration of the in-furnace gas by calculation using the hydrogen concentration. Therefore, it is possible to control the atmosphere in the gas nitriding furnace to a desired nitriding potential by calculating the nitriding potential by the above equation (2).

しかしながら、例えば、アンモニアガスと窒素ガス等、複数種類の炉内導入ガスを混合した混合ガスをガス窒化炉内へ導入して、表面硬化処理を行う場合、ガス窒化炉内へのアンモニアガスの導入量のみ、あるいは、ガス窒化炉内への窒素ガスの導入量のみを制御しても、ガス窒化炉内の雰囲気を所望の窒化ポテンシャルに制御することが不可能であるという問題を有する。
これは、表面硬化処理の状況等により、混合ガスの混合比率が変化すると、炉内ガスの組成である炉内ガス組成が把握できなくなるため、熱伝導度センサを用いて炉内ガスの水素濃度のみを検出しても、炉内ガスのアンモニア濃度を検出することが不可能となるためである。 However, for example, when surface hardening treatment is performed by introducing a mixed gas in which a plurality of types of in-furnace introduction gases such as ammonia gas and nitrogen gas are mixed into the gas nitriding furnace, the introduction of ammonia gas into the gas nitriding furnace Even if only the amount or only the amount of nitrogen gas introduced into the gas nitriding furnace is controlled, the atmosphere in the gas nitriding furnace cannot be controlled to a desired nitriding potential.
This is because, if the mixing ratio of the mixed gas changes due to the surface hardening process, etc., the furnace gas composition, which is the composition of the furnace gas, cannot be grasped. This is because it is impossible to detect the ammonia concentration of the in-furnace gas.

ところで、真空浸炭処理及び真空浸炭窒化処理においても、上述したガス窒化処理及びガス軟窒化処理と同様、例えば、アセチレンガスと窒素ガス等、複数種類の炉内導入ガスを混合した混合ガスをガス窒化炉内へ導入して、表面硬化処理を行う場合、真空浸炭炉内へのアセチレンガスの導入量のみ、あるいは、真空浸炭炉内への窒素ガスの導入量のみを制御しても、真空浸炭炉内の雰囲気を、所望の浸炭ポテンシャルに制御することが不可能であるという問題を有する。   By the way, also in the vacuum carburizing process and the vacuum carbonitriding process, similarly to the above-described gas nitriding process and gas soft nitriding process, for example, a gas mixture obtained by mixing a plurality of types of in-furnace introduction gases such as acetylene gas and nitrogen gas is gas-nitrided When the surface hardening treatment is performed by introducing into the furnace, the vacuum carburizing furnace can be controlled by controlling only the amount of acetylene gas introduced into the vacuum carburizing furnace or only the amount of nitrogen gas introduced into the vacuum carburizing furnace. There is a problem that it is impossible to control the inner atmosphere to a desired carburizing potential.

これは、上述したガス窒化処理及びガス軟窒化処理と同様、混合ガスの混合比率が変化すると、炉内ガスの組成である炉内ガス組成が把握できなくなるため、熱伝導度センサを用いて炉内ガスの水素濃度のみを検出しても、炉内ガスのアセチレン濃度を検出することが不可能となるためである。
また、真空浸炭窒化処理や真空窒化処理においても、複数種類の炉内導入ガスを混合した混合ガスをガス窒化炉内へ導入して、表面硬化処理を行う場合、熱伝導度センサを用いて炉内ガスの水素濃度のみを検出しても、炉内ガスのアセチレンやアンモニアの濃度を検出することが不可能となるため、真空浸炭炉内の雰囲気を、所望の浸炭ポテンシャルや窒化ポテンシャルに制御することが不可能であるという問題を有する。 As in the gas nitriding treatment and gas soft nitriding treatment described above, if the mixing ratio of the mixed gas is changed, the in-furnace gas composition that is the composition of the in-furnace gas cannot be grasped. This is because even if only the hydrogen concentration of the internal gas is detected, it is impossible to detect the acetylene concentration of the in-furnace gas.
Also, in vacuum carbonitriding and vacuum nitriding, when a mixed gas in which a plurality of types of in-furnace introduction gas is mixed is introduced into the gas nitriding furnace and surface hardening is performed, a furnace using a thermal conductivity sensor is used. Even if only the hydrogen concentration of the internal gas is detected, it becomes impossible to detect the concentrations of acetylene and ammonia in the furnace gas, so the atmosphere in the vacuum carburizing furnace is controlled to the desired carburizing potential and nitriding potential. It has the problem that it is impossible.

（構成）
次に、図１を用いて、本実施形態の表面硬化処理装置１の構成を説明する。
図１は、本実施形態の表面硬化処理装置１の構成を示す図である。
本実施形態の表面硬化処理装置１は、鋼部品や金型等、金属製の被処理品Ｓを配置した処理炉２内に、複数種類の炉内導入ガスを混合した混合ガスを導入して、被処理品Ｓの表面硬化処理を行う装置である。なお、複数種類の炉内導入ガスは、処理炉２内へ個別に導入し、処理炉２内で混合してもよい。 (Constitution)
Next, the structure of the surface hardening processing apparatus 1 of this embodiment is demonstrated using FIG.
FIG. 1 is a diagram showing a configuration of a surface hardening processing apparatus 1 according to the present embodiment.
The surface hardening processing apparatus 1 according to the present embodiment introduces a mixed gas obtained by mixing a plurality of types of in-furnace introduction gases into a processing furnace 2 in which a metal workpiece S such as a steel part or a mold is disposed. This is an apparatus for performing a surface hardening treatment of the article S to be processed. A plurality of types of in-furnace introduced gases may be individually introduced into the processing furnace 2 and mixed in the processing furnace 2.

ここで、複数種類の炉内導入ガスのうち少なくとも一種類の炉内導入ガスは、アンモニアガス（ＮＨ３）等、処理炉２内で水素を発生する炉内導入ガスとする。すなわち、複数種類の炉内導入ガスは、処理炉２内で水素を発生する少なくとも一種類の炉内導入ガスを含む。
なお、本実施形態では、複数種類の炉内導入ガスを、アンモニアガス（ＮＨ３）と窒素ガス（Ｎ２）の、二種類の炉内導入ガスとした場合を例に挙げて説明する。また、本実施形態では、表面硬化処理を、ガス窒化処理とした場合を例に挙げて説明する。 Here, at least one kind of in-furnace introduction gas among the plural kinds of in-furnace introduction gases is an in-furnace introduction gas that generates hydrogen in the processing furnace 2 such as ammonia gas (NH 3 ). That is, the plurality of types of in-furnace introduced gases include at least one in-furnace introduced gas that generates hydrogen in the processing furnace 2.
In the present embodiment, a case where a plurality of types of in-furnace introduction gases are two types of in-furnace introduction gases, ammonia gas (NH 3 ) and nitrogen gas (N 2 ) will be described as an example. In the present embodiment, a case where the surface hardening process is a gas nitriding process will be described as an example.

また、本実施形態では、表面硬化処理を、ガス窒化処理とした場合を説明するため、処理炉２内で水素を発生する炉内導入ガスを、アンモニアガス（ＮＨ３）とし、その他の炉内導入ガスを、窒素ガス（Ｎ２）とする。
また、本実施形態では、一例として、表面硬化処理を行う条件を、処理炉２内の温度（処理温度）を３００〜１１００℃の範囲内とし、処理炉２内の圧力（処理圧力）を１３〜１３３０００Ｐａの範囲内とする。 Further, in this embodiment, in order to explain the case where the surface hardening process is a gas nitriding process, the furnace introduction gas for generating hydrogen in the processing furnace 2 is ammonia gas (NH 3 ), and other furnaces are used. The introduced gas is nitrogen gas (N 2 ).
Moreover, in this embodiment, as an example, the conditions for performing the surface hardening treatment are set such that the temperature (processing temperature) in the processing furnace 2 is in the range of 300 to 1100 ° C., and the pressure (processing pressure) in the processing furnace 2 is 13. Within the range of ~ 133000Pa.

以下、表面硬化処理装置１の具体的な構成を説明する。
図１中に示すように、表面硬化処理装置１は、処理炉２と、水素濃度検出手段４と、調節計６と、記録計８と、開閉弁１０と、開閉弁切換え制御手段１２と、炉内導入ガス供給部１４を備えている。
処理炉２は、アンモニアガス（ＮＨ３）及び窒素ガス（Ｎ２）を導入可能であり、且つ被処理品Ｓを配置可能に形成されており、攪拌ファン１６と、攪拌ファン駆動モータ１８と、炉内温度計測手段２０を備えている。 Hereinafter, the specific structure of the surface hardening processing apparatus 1 is demonstrated.
As shown in FIG. 1, the surface hardening processing apparatus 1 includes a processing furnace 2, a hydrogen concentration detection means 4, a controller 6, a recorder 8, an on-off valve 10, an on-off valve switching control means 12, A furnace introduction gas supply unit 14 is provided.
The processing furnace 2 is configured to be able to introduce ammonia gas (NH 3 ) and nitrogen gas (N 2 ) and to be disposed with the article to be processed S, and includes a stirring fan 16, a stirring fan drive motor 18, Furnace temperature measuring means 20 is provided.

攪拌ファン１６は、処理炉２内に配置されており、処理炉２内で回転することにより、処理炉２内の雰囲気を攪拌する。
攪拌ファン駆動モータ１８は、攪拌ファン１６に連結されており、攪拌ファン１６を任意の回転速度で回転させる。
炉内温度計測手段２０は、熱電対を備えており、処理炉２内に存在している炉内ガスの温度を計測可能に構成されている。 The stirring fan 16 is disposed in the processing furnace 2, and agitates the atmosphere in the processing furnace 2 by rotating in the processing furnace 2.
The stirring fan drive motor 18 is connected to the stirring fan 16 and rotates the stirring fan 16 at an arbitrary rotation speed.
The in-furnace temperature measuring means 20 includes a thermocouple, and is configured to measure the temperature of the in-furnace gas existing in the processing furnace 2.

また、炉内温度計測手段２０は、炉内ガスの温度を計測すると、この計測した温度を含む情報信号（炉内温度信号）を、調節計６及び記録計８へ出力する。
水素濃度検出手段４は、炉内ガスの水素濃度を検出可能な構成の熱伝導度センサにより形成されており、水素濃度を検出するためのセンサ部は、水素濃度検出配管２２を介して処理炉２の内部と連通している。なお、炉内ガスの水素濃度は、炉内ガスの熱伝導度に基づいて検出する。 Further, when the furnace temperature measuring means 20 measures the temperature of the furnace gas, it outputs an information signal (furnace temperature signal) including the measured temperature to the controller 6 and the recorder 8.
The hydrogen concentration detection means 4 is formed by a thermal conductivity sensor having a configuration capable of detecting the hydrogen concentration of the gas in the furnace, and the sensor unit for detecting the hydrogen concentration is a processing furnace via the hydrogen concentration detection pipe 22. 2 communicates with the inside. Note that the hydrogen concentration of the furnace gas is detected based on the thermal conductivity of the furnace gas.

また、水素濃度検出手段４は、炉内ガスの水素濃度を検出すると、この検出した水素濃度を含む情報信号（水素濃度信号）を、調節計６及び記録計８へ出力する。
水素濃度検出配管２２は、処理炉２と水素濃度検出手段４とを連通する配管である。なお、本実施形態では、水素濃度検出配管２２を、処理炉２と水素濃度検出手段４とを直接連通させる単線の経路で形成する。 Further, when the hydrogen concentration detecting means 4 detects the hydrogen concentration of the in-furnace gas, it outputs an information signal (hydrogen concentration signal) including the detected hydrogen concentration to the controller 6 and the recorder 8.
The hydrogen concentration detection pipe 22 is a pipe that connects the processing furnace 2 and the hydrogen concentration detection means 4. In the present embodiment, the hydrogen concentration detection pipe 22 is formed by a single-wire path that directly connects the processing furnace 2 and the hydrogen concentration detection means 4.

調節計６は、ＣＰＵ（ＣＥＮＴＲＡＬ ＰＲＯＣＥＳＳＩＮＧ ＵＮＩＴ）等を備えて構成されており、炉内ガス組成演算手段２４と、ガス導入量制御手段２６を備えている。
炉内ガス組成演算手段２４は、水素濃度検出手段４が検出した水素濃度に基づいて、炉内ガスの組成である炉内ガス組成を演算する。そして、この演算した炉内ガス組成を含む情報信号（炉内ガス組成信号）をガス導入量制御手段２６へ出力する。
具体的には、炉内ガス組成演算手段２４は、炉内ガスの熱伝導度に基づいて検出した炉内ガスの水素濃度に応じて、処理炉２内で水素を発生する炉内導入ガスの炉内濃度を演算して求める。 The controller 6 includes a CPU (CENTRAL PROCESSING UNIT) and the like, and includes a furnace gas composition calculation unit 24 and a gas introduction amount control unit 26.
The in-furnace gas composition calculation means 24 calculates the in-furnace gas composition that is the composition of the in-furnace gas based on the hydrogen concentration detected by the hydrogen concentration detection means 4. Then, an information signal (in-furnace gas composition signal) including the calculated in-furnace gas composition is output to the gas introduction amount control means 26.
Specifically, the in-furnace gas composition calculating means 24 is configured to supply the in-furnace introduced gas that generates hydrogen in the processing furnace 2 according to the hydrogen concentration of the in-furnace gas detected based on the thermal conductivity of the in-furnace gas. Calculate the furnace concentration.

そして、炉内ガス組成演算手段２４は、上記の測定及び演算による各ガス分圧に基づいて、炉内ガスの組成である炉内ガス組成を演算する。これにより、本実施形態のように、表面硬化処理を、ガス窒化処理とした場合では、炉内ガスの水素濃度に基づいて、炉内ガスのアンモニア濃度を演算して求める。この測定した炉内ガスの水素濃度及びアンモニア濃度は、処理炉２内の雰囲気を反映する要素であるため、炉内ガスの水素濃度及びアンモニア濃度に基づいて、処理炉２内の窒化ポテンシャルを検出することが可能となる。   Then, the in-furnace gas composition calculation means 24 calculates the in-furnace gas composition, which is the composition of the in-furnace gas, based on each gas partial pressure obtained by the above measurement and calculation. Thus, as in the present embodiment, when the surface hardening process is a gas nitriding process, the ammonia concentration of the furnace gas is calculated based on the hydrogen concentration of the furnace gas. Since the measured hydrogen concentration and ammonia concentration in the furnace gas reflect the atmosphere in the processing furnace 2, the nitriding potential in the processing furnace 2 is detected based on the hydrogen concentration and ammonia concentration in the furnace gas. It becomes possible to do.

なお、表面硬化処理が、真空浸炭処理や真空浸炭窒化処理である場合は、炉内ガスの水素濃度に基づいて、炉内ガスのアセチレン濃度を演算して求める。
ガス導入量制御手段２６は、炉内ガス組成演算手段２４が演算した炉内ガス組成と、予め設定した設定炉内ガス混合比率に応じて、炉内ガス組成が設定炉内ガス混合比率となるように、複数種類の炉内導入ガスの処理炉２内への導入量を制御する。なお、設定炉内ガス混合比率は、表面硬化処理の種類及び複数種類の炉内導入ガスに応じて設定する値であり、予め、ガス導入量制御手段２６に記憶しておく。また、ガス導入量制御手段２６が行う制御については、後述する。 When the surface hardening process is a vacuum carburizing process or a vacuum carbonitriding process, the acetylene concentration of the furnace gas is calculated based on the hydrogen concentration of the furnace gas.
The gas introduction amount control means 26 has an in-furnace gas composition that is a set in-furnace gas mixing ratio according to the in-furnace gas composition calculated by the in-furnace gas composition calculating means 24 and a preset in-furnace gas mixing ratio. In this way, the amount of introduction of a plurality of types of in-furnace gases into the processing furnace 2 is controlled. The set in-furnace gas mixing ratio is a value set according to the type of surface hardening treatment and a plurality of types of in-furnace introduced gas, and is stored in the gas introduction amount control means 26 in advance. Control performed by the gas introduction amount control means 26 will be described later.

また、ガス導入量制御手段２６は、複数種類の炉内導入ガスの処理炉２内への導入量を制御している状態では、その作動状態を示す情報信号（制御実施信号）を、開閉弁切換え制御手段１２及び炉内導入ガス供給部１４へ出力する。
記録計８は、ＣＰＵ等やメモリ等の記憶媒体を備えて形成されている。
また、記録計８は、炉内温度計測手段２０及び水素濃度検出手段４が出力した情報信号に基づいて、処理炉２内の温度と炉内ガスの水素濃度を、例えば、表面硬化処理を行った日時と対応させて記憶する。
開閉弁１０は、水素濃度検出配管２２に取り付けられて、処理炉２と水素濃度検出手段４との間に介装された弁である。 In addition, the gas introduction amount control means 26 sends an information signal (control execution signal) indicating the operation state to the on-off valve in a state where the introduction amounts of plural types of in-furnace introduction gases into the processing furnace 2 are controlled. Output to the switching control means 12 and the in-furnace gas supply unit 14.
The recorder 8 is formed with a storage medium such as a CPU or a memory.
Further, the recorder 8 performs, for example, surface hardening treatment on the temperature in the processing furnace 2 and the hydrogen concentration in the furnace gas based on the information signal output from the furnace temperature measuring means 20 and the hydrogen concentration detecting means 4. The date and time are stored in correspondence with each other.
The on-off valve 10 is a valve attached to the hydrogen concentration detection pipe 22 and interposed between the processing furnace 2 and the hydrogen concentration detection means 4.

また、開閉弁１０は、開閉弁切換え制御手段１２が出力する制御信号（開閉制御信号）に応じて、連通状態と閉鎖状態を切換可能に形成されている。
ここで、連通状態とは、処理炉２と水素濃度検出手段４とを連通させる状態であり、閉鎖状態とは、処理炉２と水素濃度検出手段４との間を閉鎖する状態である。
開閉弁切換え制御手段１２は、ガス導入量制御手段２６の動作状態に応じて、開閉弁１０を連通状態または閉鎖状態に切り換える。なお、ガス導入量制御手段２６の動作状態は、ガス導入量制御手段２６が出力する情報信号（制御実施信号）に基づいて検出する。 The on-off valve 10 is configured to be able to switch between a communication state and a closed state in accordance with a control signal (open / close control signal) output by the on-off valve switching control means 12.
Here, the communication state is a state in which the processing furnace 2 and the hydrogen concentration detection means 4 are in communication, and the closed state is a state in which the space between the processing furnace 2 and the hydrogen concentration detection means 4 is closed.
The on-off valve switching control means 12 switches the on-off valve 10 to the communication state or the closed state according to the operating state of the gas introduction amount control means 26. The operating state of the gas introduction amount control means 26 is detected based on an information signal (control execution signal) output from the gas introduction amount control means 26.

なお、本実施形態では、具体例として、以下に示す条件により、開閉弁切換え制御手段１２が、開閉弁１０を連通状態または閉鎖状態に切り換える場合を説明する。
具体的に、開閉弁切換え制御手段１２は、ガス導入量制御手段２６が炉内導入ガスの導入量を制御している状態では、開閉弁１０を連通状態に切り換える。一方、開閉弁切換え制御手段１２は、ガス導入量制御手段２６が炉内導入ガスの導入量を制御していない状態では、開閉弁１０を閉鎖状態に切り換える。 In the present embodiment, as a specific example, a case will be described in which the on-off valve switching control means 12 switches the on-off valve 10 to a communication state or a closed state under the following conditions.
Specifically, the on-off valve switching control means 12 switches the on-off valve 10 to the communication state when the gas introduction amount control means 26 controls the introduction amount of the in-furnace introduction gas. On the other hand, the on-off valve switching control means 12 switches the on-off valve 10 to the closed state when the gas introduction amount control means 26 is not controlling the introduction amount of the in-furnace introduction gas.

炉内導入ガス供給部１４は、第一炉内導入ガス供給部２８と、第一炉内導入ガス供給量制御部３０と、第一供給弁３２と、第一炉内導入ガス流量計３４と、第二炉内導入ガス供給部３６と、第二炉内導入ガス供給量制御部３８と、第二供給弁４０と、第二炉内導入ガス流量計４２と、炉内導入ガス導入配管４４を備えている。
第一炉内導入ガス供給部２８は、第一炉内導入ガスを充填したタンクにより形成されている。なお、本実施形態では、第一炉内導入ガスを、アンモニアガス（ＮＨ３）とした場合について説明する。 The in-furnace introduction gas supply unit 14 includes a first in-furnace introduction gas supply unit 28, a first in-furnace introduction gas supply amount control unit 30, a first supply valve 32, and a first in-furnace introduction gas flow meter 34. The second furnace introduction gas supply section 36, the second furnace introduction gas supply amount control section 38, the second supply valve 40, the second furnace introduction gas flow meter 42, and the furnace introduction gas introduction pipe 44 It has.
The first furnace introduction gas supply unit 28 is formed by a tank filled with the first furnace introduction gas. In the present embodiment, a case where the first furnace introduction gas is ammonia gas (NH 3 ) will be described.

第一炉内導入ガス供給量制御部３０は、開度を変化可能なマスフローコントローラにより形成されており、第一炉内導入ガス供給部２８と第一供給弁３２との間に介装されている。なお、第一炉内導入ガス供給量制御部３０の開度は、ガス導入量制御手段２６が出力する制御信号（導入量制御信号）に応じて変化する。
また、第一炉内導入ガス供給量制御部３０は、第一炉内導入ガス供給部２８から第一供給弁３２への第一炉内導入ガスの供給量を検出し、この検出した第一炉内導入ガスの供給量を含む情報信号（第一炉内導入ガス供給量信号）を、ガス導入量制御手段２６へ出力する。この第一炉内導入ガス流量信号は、例えば、ガス導入量制御手段２６が行う制御の補正等に用いる。 The first furnace introduction gas supply amount control unit 30 is formed by a mass flow controller capable of changing the opening degree, and is interposed between the first furnace introduction gas supply unit 28 and the first supply valve 32. Yes. Note that the opening degree of the first furnace introduction gas supply amount control unit 30 changes according to a control signal (introduction amount control signal) output from the gas introduction amount control means 26.
Further, the first in-furnace introduction gas supply amount control unit 30 detects the supply amount of the first in-furnace introduction gas from the first in-furnace introduction gas supply unit 28 to the first supply valve 32, and this detected first An information signal including the supply amount of the in-furnace introduction gas (first in-furnace introduction gas supply amount signal) is output to the gas introduction amount control means 26. This first furnace introduction gas flow rate signal is used, for example, for correction of control performed by the gas introduction amount control means 26.

第一供給弁３２は、ガス導入量制御手段２６が出力する情報信号（制御実施信号）に応じて開閉状態を切り換える電磁弁により形成されており、第一炉内導入ガス供給量制御部３０と第一炉内導入ガス流量計３４との間に介装されている。
具体的には、第一供給弁３２は、ガス導入量制御手段２６が炉内導入ガスの導入量を制御している状態では、第一供給弁３２の開閉状態を、第一炉内導入ガス供給量制御部３０と第一炉内導入ガス流量計３４との間を連通させる開放状態に切り換える。一方、第一供給弁３２は、ガス導入量制御手段２６が炉内導入ガスの導入量を制御していない状態では、第一供給弁３２の開閉状態を、第一炉内導入ガス供給量制御部３０と第一炉内導入ガス流量計３４との間を閉鎖する閉鎖状態に切り換える。 The first supply valve 32 is formed by an electromagnetic valve that switches between open and closed states according to an information signal (control execution signal) output from the gas introduction amount control means 26. It is interposed between the first furnace introduction gas flow meter 34.
Specifically, the first supply valve 32 sets the open / close state of the first supply valve 32 in the state where the gas introduction amount control means 26 controls the introduction amount of the introduction gas in the furnace. The supply amount control unit 30 and the first in-furnace introduced gas flow meter 34 are switched to an open state in which communication is established. On the other hand, in the state where the gas introduction amount control means 26 does not control the introduction amount of the in-furnace introduction gas, the first supply valve 32 changes the open / close state of the first supply valve 32 to the first in-furnace introduction gas supply amount control. It switches to the closed state which closes between the part 30 and the 1st furnace introduction gas flowmeter 34. FIG.

第一炉内導入ガス流量計３４は、例えば、フロー式流量計等の機械的な流量計で形成されており、第一供給弁３２と炉内導入ガス導入配管４４との間に介装されている。
また、第一炉内導入ガス流量計３４は、第一供給弁３２から炉内導入ガス導入配管４４を通じて処理炉２へ導入される第一炉内導入ガスの流量を検出する。なお、第一炉内導入ガス流量計３４が検出した第一炉内導入ガスの流量は、例えば、表面硬化処理を行う作業員の目視による、第一炉内導入ガスの流量の確認作業に用いる。 The first furnace introduction gas flow meter 34 is formed by a mechanical flow meter such as a flow type flow meter, for example, and is interposed between the first supply valve 32 and the furnace introduction gas introduction pipe 44. ing.
The first in-furnace gas introduction flow meter 34 detects the flow rate of the first in-furnace introduction gas introduced from the first supply valve 32 into the processing furnace 2 through the in-furnace introduction gas introduction pipe 44. The flow rate of the first furnace introduction gas detected by the first furnace introduction gas flow meter 34 is used, for example, for confirming the flow rate of the first furnace introduction gas by visual observation of a worker who performs the surface hardening process. .

第二炉内導入ガス供給部３６は、第二炉内導入ガスを充填したタンクにより形成されている。なお、本実施形態では、第二炉内導入ガスを、窒素ガス（Ｎ２）とした場合について説明する。
第二炉内導入ガス供給量制御部３８は、第一炉内導入ガス供給量制御部３０と同様、開度を変化可能なマスフローコントローラにより形成されており、第二炉内導入ガス供給部３６と第二供給弁４０との間に介装されている。なお、第二炉内導入ガス供給量制御部３８の開度は、ガス導入量制御手段２６が出力する制御信号（導入量制御信号）に応じて変化する。 The second furnace introduction gas supply unit 36 is formed by a tank filled with the second furnace introduction gas. In the present embodiment, the case where the second furnace introduction gas is nitrogen gas (N 2 ) will be described.
Similar to the first in-furnace introduced gas supply amount control unit 30, the second in-furnace introduced gas supply amount control unit 38 is formed by a mass flow controller capable of changing the opening degree. And the second supply valve 40. The opening degree of the second furnace introduction gas supply amount control unit 38 changes according to a control signal (introduction amount control signal) output from the gas introduction amount control means 26.

また、第二炉内導入ガス供給量制御部３８は、第二炉内導入ガス供給部３６から第二供給弁４０への第二炉内導入ガスの供給量を検出し、この検出した第二炉内導入ガスの供給量を含む情報信号（第二炉内導入ガス供給量信号）を、ガス導入量制御手段２６へ出力する。この第二炉内導入ガス流量信号は、例えば、ガス導入量制御手段２６が行う制御の補正等に用いる。   The second in-furnace introduction gas supply amount control unit 38 detects the supply amount of the second in-furnace introduction gas from the second in-furnace introduction gas supply unit 36 to the second supply valve 40, and detects the detected second An information signal including the supply amount of the in-furnace introduction gas (second in-furnace introduction gas supply amount signal) is output to the gas introduction amount control means 26. The second furnace introduction gas flow rate signal is used, for example, for correction of control performed by the gas introduction amount control means 26.

第二供給弁４０は、第一供給弁３２と同様、ガス導入量制御手段２６が出力する情報信号（制御実施信号）に応じて開閉状態を切り換える電磁弁により形成されており、第二炉内導入ガス供給量制御部３８と第二炉内導入ガス流量計４２との間に介装されている。
具体的には、第二供給弁４０は、ガス導入量制御手段２６が炉内導入ガスの導入量を制御している状態では、第二供給弁４０の開閉状態を、第二炉内導入ガス供給量制御部３８と第二炉内導入ガス流量計４２との間を連通させる開放状態に切り換える。一方、第二供給弁４０は、ガス導入量制御手段２６が炉内導入ガスの導入量を制御していない状態では、第二供給弁４０の開閉状態を、第二炉内導入ガス供給量制御部３８と第二炉内導入ガス流量計４２との間を閉鎖する閉鎖状態に切り換える。 Similar to the first supply valve 32, the second supply valve 40 is formed by an electromagnetic valve that switches between open and closed states in accordance with an information signal (control execution signal) output from the gas introduction amount control means 26. It is interposed between the introduced gas supply amount control unit 38 and the second in-furnace introduced gas flow meter 42.
Specifically, the second supply valve 40 determines whether the second supply valve 40 is opened or closed when the gas introduction amount control means 26 controls the introduction amount of the introduction gas in the furnace. The supply amount control unit 38 and the second in-furnace introduction gas flow meter 42 are switched to an open state in which communication is established. On the other hand, in the state where the gas introduction amount control means 26 does not control the introduction amount of the in-furnace introduction gas, the second supply valve 40 sets the open / close state of the second supply valve 40 to the second in-furnace introduction gas supply amount control. It switches to the closed state which closes between the part 38 and the 2nd in-furnace introduction gas flowmeter 42. FIG.

第二炉内導入ガス流量計４２は、第一炉内導入ガス流量計３４と同様、例えば、フロー式流量計等の機械的な流量計で形成されており、第二供給弁４０と炉内導入ガス導入配管４４との間に介装されている。
また、第二炉内導入ガス流量計４２は、第二供給弁４０から炉内導入ガス導入配管４４を通じて処理炉２へ導入される第二炉内導入ガスの流量を検出する。なお、第二炉内導入ガス流量計４２が検出した第二炉内導入ガスの流量は、例えば、表面硬化処理を行う作業員の目視による、第二炉内導入ガスの流量の確認作業に用いる。 The second furnace introduction gas flow meter 42 is formed of a mechanical flow meter such as a flow type flow meter, for example, like the first furnace introduction gas flow meter 34. It is interposed between the introduction gas introduction pipe 44.
The second in-furnace gas introduction flow meter 42 detects the flow rate of the second in-furnace introduction gas introduced into the processing furnace 2 from the second supply valve 40 through the in-furnace introduction gas introduction pipe 44. The flow rate of the second furnace introduction gas detected by the second furnace introduction gas flow meter 42 is used, for example, for confirming the flow rate of the second furnace introduction gas by visual observation of an operator who performs the surface hardening process. .

炉内導入ガス導入配管４４は、第一炉内導入ガス流量計３４及び第二炉内導入ガス流量計４２と処理炉２とを連結する配管であり、第一炉内導入ガス及び第二炉内導入ガスの処理炉２への導入経路を形成している。
以下、上述した構成を前提として、ガス導入量制御手段２６が行う制御について、具体的な例を挙げて説明する。 The in-furnace introduction gas introduction pipe 44 is a pipe connecting the first in-furnace introduction gas flow meter 34 and the second in-furnace introduction gas flow meter 42 and the processing furnace 2, and the first in-furnace introduction gas and the second furnace An introduction path of the internally introduced gas to the processing furnace 2 is formed.
Hereinafter, the control performed by the gas introduction amount control means 26 will be described with specific examples on the assumption of the above-described configuration.

ガス導入量制御手段２６は、上述した式（２）で表される窒化ポテンシャルＫＮが３．３となるように、炉内ガス組成演算手段２４が演算した炉内ガス組成を参照して、アンモニアガス（ＮＨ３）の導入量と窒素ガス（Ｎ２）の導入量との比が設定炉内ガス混合比率となるように、アンモニアガス（ＮＨ３）の導入量と窒素ガス（Ｎ２）の導入量を演算する。 The gas introduction amount control means 26 refers to the in-furnace gas composition calculated by the in-furnace gas composition calculation means 24 so that the nitriding potential K N represented by the above formula (2) becomes 3.3. ammonia gas (NH 3) for introducing the amount and nitrogen gas as the ratio of the introduction amount of (N 2) is set furnace gas mixing ratio, the introduced amount and nitrogen gas (N 2) of ammonia gas (NH 3) Calculate the amount of introduction.

そして、ガス導入量制御手段２６は、演算したそれぞれのガス（ＮＨ３，Ｎ２）の導入量に基づいて、第一炉内導入ガス供給量制御部３０及び第二炉内導入ガス供給量制御部３８へ、それぞれの導入量を制御する制御信号（導入量制御信号）を出力する。
なお、ガス導入量制御手段２６が、アンモニアガス（ＮＨ３）及び窒素ガス（Ｎ２）の導入量を制御する際は、以下の二通りの制御のうち、一方を行う。
第一の制御は、処理炉２内へ導入する混合ガス（アンモニアガス＋窒素ガス）の、処理炉２内への導入量の比率である炉内導入ガス流量比率を一定値に保持した状態で、アンモニアガス（ＮＨ３）及び窒素ガス（Ｎ２）の処理炉２内への合計導入量を制御するものである。 The gas introduction amount control means 26 controls the first in-furnace introduction gas supply amount control unit 30 and the second in-furnace introduction gas supply amount control based on the calculated introduction amounts of the respective gases (NH 3 , N 2 ). A control signal (introduction amount control signal) for controlling each introduction amount is output to the unit 38.
When the gas introduction amount control means 26 controls the introduction amounts of ammonia gas (NH 3 ) and nitrogen gas (N 2 ), one of the following two types of control is performed.
In the first control, the in-furnace gas flow rate ratio, which is the ratio of the amount of the mixed gas (ammonia gas + nitrogen gas) introduced into the processing furnace 2 into the processing furnace 2, is maintained at a constant value. The total amount of ammonia gas (NH 3 ) and nitrogen gas (N 2 ) introduced into the processing furnace 2 is controlled.

一方、第二の制御は、混合ガス（アンモニアガス＋窒素ガス）の炉内導入ガス流量比率が変化するように、アンモニアガス（ＮＨ３）及び窒素ガス（Ｎ２）について、それぞれの導入量を個別に変化させる制御である。
なお、表面硬化処理が、真空浸炭処理や真空浸炭窒化処理である場合は、ガス導入量制御手段２６は、上述した式（４）で表される浸炭ポテンシャルＫＣが所望の値となるように、炉内ガス組成演算手段２４が演算した炉内ガス組成を参照して、複数種類の炉内導入ガス（アセチレンガス等）の導入量を演算する。 On the other hand, in the second control, the introduction amount of each of the ammonia gas (NH 3 ) and the nitrogen gas (N 2 ) is changed so that the flow rate ratio of the mixed gas (ammonia gas + nitrogen gas) into the furnace changes. This is a control that changes individually.
The surface hardening treatment, if a vacuum carburization and vacuum carburization nitriding treatment, gas introducing amount control means 26, as carburizing potential K C represented by the above formula (4) has a desired value Referring to the in-furnace gas composition calculated by the in-furnace gas composition calculation means 24, the introduction amounts of plural types of in-furnace introduction gases (acetylene gas, etc.) are calculated.

（動作）
以下、図１を参照して、被処理品の表面硬化処理を行う際の、本実施形態の表面硬化処理装置１の動作について説明する。
まず、処理炉２内に被処理品Ｓを配置した後、炉内導入ガス供給部１４からアンモニアガス（ＮＨ３）及び窒素ガス（Ｎ２）を混合した混合ガスを処理炉２内へ導入し、攪拌ファン駆動モータ１８を駆動させて攪拌ファン１６を回転させ、処理炉２内の雰囲気を攪拌する。 (Operation)
Hereinafter, with reference to FIG. 1, operation | movement of the surface hardening processing apparatus 1 of this embodiment at the time of performing the surface hardening process of to-be-processed goods is demonstrated.
First, after the article to be processed S is arranged in the processing furnace 2, a mixed gas obtained by mixing ammonia gas (NH 3 ) and nitrogen gas (N 2 ) is introduced into the processing furnace 2 from the in-furnace gas supply unit 14. Then, the stirring fan drive motor 18 is driven to rotate the stirring fan 16 to stir the atmosphere in the processing furnace 2.

このとき、開閉弁切換え制御手段１２は、開閉弁１０の状態を閉鎖状態に切り換え、処理炉２と水素濃度検出手段４との間を閉鎖する。これにより、炉内ガスが含む汚染成分が、センサ部を含む水素濃度検出手段４へ接触することを抑制する。なお、炉内ガスが含む汚染成分とは、例えば、被処理品Ｓに付着している油分や汚れが、処理炉２内で気化することにより、炉内ガスに含まれる。   At this time, the on-off valve switching control means 12 switches the state of the on-off valve 10 to the closed state and closes the space between the processing furnace 2 and the hydrogen concentration detecting means 4. Thereby, it is suppressed that the pollutant component which furnace gas contains contacts the hydrogen concentration detection means 4 containing a sensor part. In addition, the contamination component which furnace gas contains is contained in furnace gas by, for example, the oil component and dirt adhering to to-be-processed product S evaporating in the processing furnace 2. FIG.

ここで、本実施形態では、設定炉内ガス混合比率を、アンモニアガス（ＮＨ３）：窒素ガス（Ｎ２）＝８０：２０とする。このため、表面硬化処理を開始する際には、処理炉２内へのアンモニアガス（ＮＨ３）及び窒素ガス（Ｎ２）の導入量は、アンモニアガス（ＮＨ３）の導入量と窒素ガス（Ｎ２）の導入量との比が、８０：２０となるように、第一炉内導入ガス供給量制御部３０及び第二炉内導入ガス供給量制御部３８の開度を制御する。 Here, in this embodiment, the setting furnace gas mixing ratio is set to ammonia gas (NH 3 ): nitrogen gas (N 2 ) = 80: 20. For this reason, when the surface hardening treatment is started, the amount of ammonia gas (NH 3 ) and nitrogen gas (N 2 ) introduced into the processing furnace 2 is the same as the amount of ammonia gas (NH 3 ) introduced and nitrogen gas ( The opening degree of the first in-furnace introduced gas supply amount control unit 30 and the second in-furnace introduced gas supply amount control unit 38 is controlled so that the ratio of the introduced amount of N 2 ) to 80:20.

これに加え、図外の加熱機等を用いて、処理炉２内の温度（処理温度）を３００〜１１００℃の範囲内とし、さらに、図外のポンプ等を用いて、処理炉２内の圧力（処理圧力）を１３〜１３３０００Ｐａの範囲内とする。
このとき、炉内温度計測手段２０が、炉内ガスの温度を計測し、この計測した温度を含む情報信号（炉内温度信号）を、調節計６及び記録計８へ出力する。
調節計６が炉内温度信号の入力を受けると、ガス導入量制御手段２６は、処理炉２内の状態が、加熱機等による昇温中ではなく、処理炉２内の温度が上記の条件で安定している状態であるか否かを判定する。 In addition, the temperature in the processing furnace 2 (processing temperature) is set within a range of 300 to 1100 ° C. using a heater or the like not shown, and further, the temperature in the processing furnace 2 is set using a pump or the like not shown. The pressure (treatment pressure) is set within a range of 13 to 133000 Pa.
At this time, the furnace temperature measuring means 20 measures the temperature of the furnace gas, and outputs an information signal (furnace temperature signal) including the measured temperature to the controller 6 and the recorder 8.
When the controller 6 receives an input of the furnace temperature signal, the gas introduction amount control means 26 indicates that the state in the processing furnace 2 is not being heated by a heater or the like, and the temperature in the processing furnace 2 is the above condition. It is determined whether it is in a stable state.

そして、処理炉２内の温度が上記の条件で安定している状態であると判定すると、ガス導入量制御手段２６は、複数種類の炉内導入ガスの導入量の制御を開始する。これに加え、ガス導入量制御手段２６は、作動状態を示す制御実施信号を、開閉弁切換え制御手段１２及び炉内導入ガス供給部１４へ出力する。
制御実施信号の入力を受けた開閉弁切換え制御手段１２は、開閉弁１０の状態を連通状態に切り換える。 And if it determines with the temperature in the processing furnace 2 being the state stabilized on said conditions, the gas introduction amount control means 26 will start control of the introduction amount of several types of in-furnace introduction gas. In addition to this, the gas introduction amount control means 26 outputs a control execution signal indicating the operating state to the on-off valve switching control means 12 and the in-furnace introduction gas supply unit 14.
Upon receiving the control execution signal, the on-off valve switching control means 12 switches the state of the on-off valve 10 to the communication state.

開閉弁１０が連通状態に切り換わると、処理炉２と水素濃度検出手段４が連通し、炉内ガスが水素濃度検出配管２２内を移動して、水素濃度検出手段４のセンサ部に接触する。
炉内ガスが水素濃度検出手段４のセンサ部に接触すると、水素濃度検出手段４が炉内ガスの水素濃度を検出して、この検出した水素濃度を含む水素濃度信号を、調節計６及び記録計８へ出力する。 When the on-off valve 10 is switched to the communication state, the processing furnace 2 and the hydrogen concentration detection means 4 communicate with each other, and the gas in the furnace moves through the hydrogen concentration detection pipe 22 and contacts the sensor unit of the hydrogen concentration detection means 4. .
When the in-furnace gas comes into contact with the sensor part of the hydrogen concentration detecting means 4, the hydrogen concentration detecting means 4 detects the hydrogen concentration of the in-furnace gas and records the hydrogen concentration signal including the detected hydrogen concentration in the controller 6 and the recording. Output to a total of 8.

調節計６が水素濃度信号の入力を受けると、炉内ガス組成演算手段２４は、水素濃度検出手段４が検出した水素濃度に基づいて、炉内ガスの組成である炉内ガス組成を演算し、炉内ガス組成信号をガス導入量制御手段２６へ出力する。
炉内ガス組成信号の入力を受けたガス導入量制御手段２６は、炉内ガス組成と設定炉内ガス混合比率に応じて、炉内ガス組成が設定炉内ガス混合比率となるように、複数種類の炉内導入ガスの処理炉２内への導入量を制御する。これにより、処理炉２内の雰囲気を反映する炉内ガス組成を検出し、この検出した処理炉２内の雰囲気を参照して、処理炉２内の雰囲気を制御する。 When the controller 6 receives the input of the hydrogen concentration signal, the in-furnace gas composition calculation means 24 calculates the in-furnace gas composition, which is the composition of the in-furnace gas, based on the hydrogen concentration detected by the hydrogen concentration detection means 4. Then, the in-furnace gas composition signal is output to the gas introduction amount control means 26.
The gas introduction amount control means 26 that has received the in-furnace gas composition signal has a plurality of gas introduction ratios in accordance with the in-furnace gas composition and the set in-furnace gas mixing ratio. The amount of introduction of different types of in-furnace gas into the processing furnace 2 is controlled. Thereby, the gas composition in the furnace reflecting the atmosphere in the processing furnace 2 is detected, and the atmosphere in the processing furnace 2 is controlled with reference to the detected atmosphere in the processing furnace 2.

複数種類の炉内導入ガスの処理炉２内への導入量を制御して、処理炉２内の雰囲気を制御した状態で、被処理品Ｓの材質や量等に応じて設定した所定の時間、被処理品Ｓの表面硬化処理を行う。
被処理品Ｓの表面硬化処理を行う間、ガス導入量制御手段２６が、複数種類の炉内導入ガスの処理炉２内への導入量を制御しておらず、制御実施信号を出力していない状態では、開閉弁切換え制御手段１２が、開閉弁１０を閉鎖状態に切り換える。 A predetermined time set in accordance with the material, amount, etc. of the article to be processed S in a state where the introduction amount of the plurality of types of in-furnace gases into the processing furnace 2 is controlled and the atmosphere in the processing furnace 2 is controlled. Then, the surface hardening treatment of the article to be processed S is performed.
While performing the surface hardening process of the workpiece S, the gas introduction amount control means 26 does not control the introduction amounts of the plurality of types of in-furnace introduction gases into the processing furnace 2 and outputs a control execution signal. In the absence, the on-off valve switching control means 12 switches the on-off valve 10 to the closed state.

以上説明したように、表面硬化処理装置１を用いた表面硬化処理方法は、複数種類の炉内導入ガスを処理炉２内へ導入して、処理炉２内に配置した被処理品Ｓの表面硬化処理を行う表面硬化処理方法である。ここで、複数種類の炉内導入ガスは、処理炉２内で水素を発生する少なくとも一種類の炉内導入ガスを含む。
また、表面硬化処理方法は、処理炉２内の炉内ガスの熱伝導度に基づいて、炉内ガスの水素濃度を検出し、検出した水素濃度に基づいて、炉内ガスの組成である炉内ガス組成を演算するステップを含む。 As described above, the surface hardening processing method using the surface hardening processing apparatus 1 introduces a plurality of types of in-furnace introduction gases into the processing furnace 2, and the surface of the workpiece S disposed in the processing furnace 2. This is a surface hardening treatment method for carrying out a hardening treatment. Here, the plurality of types of in-furnace introduced gases include at least one in-furnace introduced gas that generates hydrogen in the processing furnace 2.
Further, the surface hardening treatment method detects the hydrogen concentration of the in-furnace gas based on the thermal conductivity of the in-furnace gas in the treatment furnace 2, and the furnace having the composition of the in-furnace gas based on the detected hydrogen concentration. Calculating the internal gas composition.

さらに、表面硬化処理方法は、演算した炉内ガス組成と予め設定した設定炉内ガス混合比率に応じて、炉内ガス組成が設定炉内ガス混合比率となるように、複数種類の炉内導入ガスの処理炉２内への導入量の比率である炉内導入ガス流量比率を一定値に保持した状態で、複数種類の炉内導入ガスの処理炉２内への合計導入量を制御するステップ、または、炉内導入ガス流量比率が変化するように複数種類の炉内導入ガスの導入量を個別に制御するステップを含む。   Furthermore, the surface hardening treatment method is introduced into a plurality of types of furnaces so that the furnace gas composition becomes the set furnace gas mixture ratio according to the calculated furnace gas composition and the preset furnace gas mixture ratio. The step of controlling the total amount of introduction of a plurality of types of in-furnace gases introduced into the processing furnace 2 in a state where the in-furnace introduction gas flow rate ratio, which is the ratio of the amount of gas introduced into the processing furnace 2, is maintained at a constant value. Or a step of individually controlling the introduction amounts of the plurality of types of in-furnace introduction gases so that the in-furnace introduction gas flow rate ratio changes.

（第一実施形態の効果）
以下、本実施形態の効果を列挙する。
（１）本実施形態の表面硬化処理装置１では、水素濃度検出手段４が、炉内ガスの熱伝導度に基づいて検出した炉内ガスの水素濃度に応じて、処理炉２内で水素を発生する炉内導入ガスの炉内濃度を演算して求める。 (Effects of the first embodiment)
The effects of this embodiment are listed below.
(1) In the surface hardening treatment apparatus 1 of the present embodiment, the hydrogen concentration detection means 4 generates hydrogen in the treatment furnace 2 according to the hydrogen concentration of the furnace gas detected based on the thermal conductivity of the furnace gas. Calculate the in-furnace concentration of the gas introduced into the furnace.

そして、この測定した演算値に基づいて、炉内ガス組成演算手段２４が、炉内ガスの組成である炉内ガス組成を演算する。
このため、演算した炉内ガス組成と予め設定した設定炉内ガス混合比率に応じて、処理炉２内の雰囲気を検出し、この検出した雰囲気を参照して、ガス導入量制御手段２６が、炉内ガス組成が設定炉内ガス混合比率となるように、複数種類の炉内導入ガスの導入量を制御することが可能となる。 Then, based on the measured calculated value, the in-furnace gas composition calculating means 24 calculates the in-furnace gas composition which is the composition of the in-furnace gas.
For this reason, the atmosphere in the processing furnace 2 is detected according to the calculated in-furnace gas composition and the preset in-furnace gas mixing ratio, and the gas introduction amount control means 26 refers to the detected atmosphere, It is possible to control the introduction amounts of a plurality of types of in-furnace introduced gases so that the in-furnace gas composition becomes the set in-furnace gas mixing ratio.

その結果、炉内ガス組成と設定炉内ガス混合比率に応じて検出した処理炉２内の雰囲気を参照して、処理炉２内の雰囲気を制御することが可能となるため、表面硬化処理に要するランニングコストを減少させることが可能となる。
また、大気中へのガス排出量を減少させることが可能となるため、環境の悪化を抑制することが可能となる。 As a result, it is possible to control the atmosphere in the processing furnace 2 with reference to the atmosphere in the processing furnace 2 detected according to the gas composition in the furnace and the gas mixing ratio in the set furnace, and thus the surface hardening treatment is performed. The running cost required can be reduced.
Moreover, since it becomes possible to reduce the gas discharge | emission amount to air | atmosphere, it becomes possible to suppress deterioration of an environment.

（２）本実施形態の表面硬化処理装置１では、開閉弁切換え制御手段１２が、ガス導入量制御手段２６が炉内導入ガスの導入量を制御している状態では、開閉弁１０を連通状態に切り換えて、処理炉２と水素濃度検出手段４とを連通させる。
一方、開閉弁切換え制御手段１２が、ガス導入量制御手段２６が炉内導入ガスの導入量を制御していない状態では、開閉弁１０を閉鎖状態に切り換えて、処理炉２と水素濃度検出手段４との間を閉鎖する。
このため、ガス導入量制御手段２６が炉内導入ガスの導入量を制御していない状態において、炉内ガスが含む汚染成分が、センサ部を含む水素濃度検出手段４へ接触することを抑制可能となる。 (2) In the surface hardening treatment apparatus 1 of the present embodiment, the on-off valve switching control means 12 is in communication with the on-off valve 10 in a state where the gas introduction amount control means 26 controls the introduction amount of the gas introduced into the furnace. The processing furnace 2 and the hydrogen concentration detecting means 4 are communicated with each other.
On the other hand, when the on-off valve switching control means 12 is in a state where the gas introduction amount control means 26 is not controlling the introduction amount of the in-furnace introduction gas, the on-off valve 10 is switched to the closed state, and the processing furnace 2 and the hydrogen concentration detection means. 4 is closed.
For this reason, in a state where the gas introduction amount control means 26 does not control the introduction amount of the in-furnace introduction gas, it is possible to suppress the contamination component contained in the in-furnace gas from coming into contact with the hydrogen concentration detection means 4 including the sensor unit. It becomes.

その結果、水素濃度検出手段４の検出精度が低下することを、長期間に亘り抑制することが可能となるため、水素濃度検出手段４の検出精度を長期間に亘って維持することが可能となる。
なお、表面硬化処理が、真空浸炭処理や真空浸炭窒化処理である場合は、処理炉２内で発生した煤やタールが熱伝導度センサに導入されることを抑制可能となり、水素濃度検出手段４の検出精度が低下することを、長期間に亘り抑制することが可能となる。 As a result, it is possible to suppress the detection accuracy of the hydrogen concentration detection means 4 from deteriorating over a long period of time, so that the detection accuracy of the hydrogen concentration detection means 4 can be maintained over a long period of time. Become.
When the surface hardening process is a vacuum carburizing process or a vacuum carbonitriding process, it is possible to suppress soot and tar generated in the processing furnace 2 from being introduced into the thermal conductivity sensor, and the hydrogen concentration detecting means 4 It is possible to suppress a decrease in the detection accuracy for a long period of time.

（３）本実施形態の表面硬化処理方法では、炉内ガスの熱伝導度に基づいて検出した炉内ガスの水素濃度に応じて、処理炉２内で水素を発生する炉内導入ガスの炉内濃度を演算して求める。そして、この演算値に基づいて、炉内ガスの組成である炉内ガス組成を演算する。
このため、演算した炉内ガス組成と予め設定した設定炉内ガス混合比率に応じて、処理炉２内の雰囲気を検出し、この検出した雰囲気を参照して、炉内ガス組成が設定炉内ガス混合比率となるように、複数種類の炉内導入ガスの導入量を制御することが可能となる。 (3) In the surface hardening treatment method according to the present embodiment, a furnace for introducing an in-furnace gas that generates hydrogen in the treatment furnace 2 in accordance with the hydrogen concentration of the in-furnace gas detected based on the thermal conductivity of the in-furnace gas. Calculate the internal concentration. And based on this calculated value, the in-furnace gas composition which is a composition of the in-furnace gas is calculated.
Therefore, the atmosphere in the processing furnace 2 is detected in accordance with the calculated in-furnace gas composition and the preset in-furnace gas mixing ratio, and the in-furnace gas composition is set in the set furnace with reference to the detected atmosphere. It is possible to control the amount of introduction of a plurality of types of in-furnace gases so that the gas mixing ratio is achieved.

その結果、炉内ガス組成と設定炉内ガス混合比率に応じて検出した処理炉２内の雰囲気を参照して、処理炉２内の雰囲気を制御することが可能となるため、表面硬化処理に要するランニングコストを減少させることが可能となる。
また、大気中へのガス排出量を減少させることが可能となるため、環境の悪化を抑制することが可能となる。 As a result, it is possible to control the atmosphere in the processing furnace 2 with reference to the atmosphere in the processing furnace 2 detected according to the gas composition in the furnace and the gas mixing ratio in the set furnace, and thus the surface hardening treatment is performed. The running cost required can be reduced.
Moreover, since it becomes possible to reduce the gas discharge | emission amount to air | atmosphere, it becomes possible to suppress deterioration of an environment.

（応用例）
以下、本実施形態の応用例を列挙する。
（１）本実施形態の表面硬化処理装置１では、水素濃度検出配管２２を、処理炉２と水素濃度検出手段４とを直接連通させる単線の経路で形成したが、これに限定するものではない。すなわち、水素濃度検出配管２２を、図２中に示すように、処理炉２と水素濃度検出手段４との間で複数の経路に分岐する複線の経路で形成してもよい。なお、図２は、第一実施形態の変形例の構成を示す図である。また、図２中では、処理炉２、水素濃度検出手段４、水素濃度検出配管２２及び開閉弁１０以外の図示を省略している。 (Application examples)
Hereinafter, application examples of this embodiment will be listed.
(1) In the surface hardening processing apparatus 1 of the present embodiment, the hydrogen concentration detection pipe 22 is formed by a single-wire path that directly connects the processing furnace 2 and the hydrogen concentration detection means 4, but the present invention is not limited to this. . That is, as shown in FIG. 2, the hydrogen concentration detection pipe 22 may be formed by a double-line path that branches into a plurality of paths between the processing furnace 2 and the hydrogen concentration detection means 4. In addition, FIG. 2 is a figure which shows the structure of the modification of 1st embodiment. 2, illustrations other than the processing furnace 2, the hydrogen concentration detection means 4, the hydrogen concentration detection pipe 22, and the on-off valve 10 are omitted.

この場合、水素濃度検出配管２２は、処理炉２と水素濃度検出手段４とを連通する第一配管２２ａと、処理炉２と第一配管２２ａとを連通する第二配管２２ｂと、第一配管２２ａと連通する第三配管２２ｃから形成する。
そして、第一配管２２ａ、第二配管２２ｂ及び第三配管２２ｃが形成する経路に、それぞれ、開閉弁１０を介装する。この場合、図２中に示すように、第一配管２２ａに介装する開閉弁１０を第一開閉弁１０ａとし、第二配管２２ｂに介装する開閉弁１０を第二開閉弁１０ｂとし、第三配管２２ｃに介装する開閉弁１０を第三開閉弁１０ｃとする。 In this case, the hydrogen concentration detection pipe 22 includes a first pipe 22a that communicates the processing furnace 2 and the hydrogen concentration detection means 4, a second pipe 22b that communicates the processing furnace 2 and the first pipe 22a, and a first pipe. It forms from the 3rd piping 22c connected to 22a.
And the on-off valve 10 is interposed in the path | route which the 1st piping 22a, the 2nd piping 22b, and the 3rd piping 22c form, respectively. In this case, as shown in FIG. 2, the on-off valve 10 interposed in the first pipe 22a is the first on-off valve 10a, the on-off valve 10 interposed in the second pipe 22b is the second on-off valve 10b, The on-off valve 10 interposed in the three pipes 22c is referred to as a third on-off valve 10c.

水素濃度検出配管２２及び開閉弁１０の構成を、図２中に示す構成とすると、水素濃度検出手段４の応答性を向上させることが可能となる。これに加え、水素濃度検出配管２２に残留しているガスの排気や、水素濃度検出手段４のチェックを行うことが容易となる。このため、水素濃度検出手段４の検出精度を長期間に亘って維持することが可能となる。
具体的には、ガス導入量制御手段２６が炉内導入ガスの導入量を制御している状態では、第三開閉弁１０ｃを閉鎖状態とし、第一開閉弁１０ａ及び第二開閉弁１０ｂを連通状態とすることにより、炉内ガスの流れが良好となる。このため、炉内ガスのうち、偏った成分のみが水素濃度検出手段４へ導入されることを抑制して、処理炉２内の雰囲気全体の水素濃度を正確に反映することが可能となり、水素濃度検出手段４の検出精度を向上させることが可能となる。 If the configuration of the hydrogen concentration detection pipe 22 and the on-off valve 10 is the configuration shown in FIG. 2, the responsiveness of the hydrogen concentration detection means 4 can be improved. In addition, it becomes easy to exhaust the gas remaining in the hydrogen concentration detection pipe 22 and check the hydrogen concentration detection means 4. For this reason, it becomes possible to maintain the detection accuracy of the hydrogen concentration detection means 4 over a long period of time.
Specifically, when the gas introduction amount control means 26 controls the introduction amount of the in-furnace introduction gas, the third on-off valve 10c is closed and the first on-off valve 10a and the second on-off valve 10b are communicated. By making the state, the flow of the gas in the furnace becomes good. For this reason, it is possible to accurately reflect the hydrogen concentration of the entire atmosphere in the processing furnace 2 by suppressing the introduction of only biased components of the gas in the furnace into the hydrogen concentration detecting means 4. It becomes possible to improve the detection accuracy of the concentration detection means 4.

また、炉内ガスの流れが良好となると、炉内ガスが水素濃度検出手段４へ導入されるまでの時間を短縮することが可能となるため、水素濃度検出手段４の応答性を向上させることが可能となる。
一方、ガス導入量制御手段２６が炉内導入ガスの導入量を制御していない状態では、第一開閉弁１０ａを閉鎖状態とし、第二開閉弁１０ｂ及び第三開閉弁１０ｃを連通状態とすることにより、第三開閉弁１０ｃから窒素ガス等の清浄なガスを導入し、その後、第二開閉弁１０ｂ及び第三開閉弁１０ｃを閉鎖状態とすることにより、第三配管２２ｃ内に残留している炉内ガスを排気することが可能となる。このため、次に行う表面硬化処理において、炉内ガスの水素濃度を検出するまでに、水素濃度検出配管２２内を清浄な状態に保持することが可能となるため、水素濃度検出手段４の検出精度を長期間に亘って維持することが可能となる。 Further, when the flow of the gas in the furnace becomes good, the time until the gas in the furnace is introduced into the hydrogen concentration detection means 4 can be shortened, so that the responsiveness of the hydrogen concentration detection means 4 is improved. Is possible.
On the other hand, in a state where the gas introduction amount control means 26 does not control the introduction amount of the in-furnace introduction gas, the first on-off valve 10a is closed and the second on-off valve 10b and the third on-off valve 10c are in communication. Thus, a clean gas such as nitrogen gas is introduced from the third on-off valve 10c, and then the second on-off valve 10b and the third on-off valve 10c are closed to remain in the third pipe 22c. It is possible to exhaust the in-furnace gas. For this reason, in the next surface hardening treatment, the hydrogen concentration detection pipe 22 can be kept clean until the hydrogen concentration of the in-furnace gas is detected. The accuracy can be maintained over a long period of time.

また、表面硬化処理を行っていない状態では、第一開閉弁１０ａを閉鎖状態とし、第二開閉弁１０ｂ及び第三開閉弁１０ｃを連通状態とし、第三開閉弁１０ｃから窒素ガスなどの清浄なガスを導入することにより、水素濃度検出手段４のゼロ点調整を行うことが可能となる。また、水素濃度が明確なガス（標準水素ガス）を水素濃度検出手段４へ導入することにより、水素濃度検出手段４のスパン調整を行うことが可能となり、水素濃度検出手段４の検出精度を長期間に亘って維持することが可能となる。   Further, when the surface hardening treatment is not performed, the first on-off valve 10a is closed, the second on-off valve 10b and the third on-off valve 10c are in communication, and a clean gas such as nitrogen gas is supplied from the third on-off valve 10c. By introducing the gas, the zero point adjustment of the hydrogen concentration detecting means 4 can be performed. In addition, by introducing a gas with a clear hydrogen concentration (standard hydrogen gas) into the hydrogen concentration detection means 4, the span of the hydrogen concentration detection means 4 can be adjusted, and the detection accuracy of the hydrogen concentration detection means 4 is increased. It can be maintained over a period of time.

（２）本実施形態の表面硬化処理装置１では、第一炉内導入ガス供給量制御部３０及び第二炉内導入ガス供給量制御部３８を、マスフローコントローラにより形成したが、これに限定するものではない。すなわち、第一炉内導入ガス供給量制御部３０及び第二炉内導入ガス供給量制御部３８を、安価な手動式のフロー式流量計で形成するとともに、流量を予め設定した複数個のガス流量計をフロー式流量計及び自動開閉弁と組み合わせて、第一炉内導入ガス供給量制御部３０及び第二炉内導入ガス供給量制御部３８を形成してもよい。 (2) In the surface hardening treatment apparatus 1 of the present embodiment, the first furnace introduction gas supply amount control unit 30 and the second furnace introduction gas supply amount control unit 38 are formed by the mass flow controller, but the present invention is limited to this. It is not a thing. That is, the first in-furnace introduced gas supply amount control unit 30 and the second in-furnace introduction gas supply amount control unit 38 are formed by an inexpensive manual flow type flow meter, and a plurality of gases whose flow rates are preset. The first in-furnace introduction gas supply amount control unit 30 and the second in-furnace introduction gas supply amount control unit 38 may be formed by combining a flow meter with a flow type flow meter and an automatic on-off valve.

（第二実施形態）
以下、本発明の第二実施形態（以下、「本実施形態」と記載する）について、図面を参照しつつ説明する。
（構成）
図３は、本実施形態の表面硬化処理装置１の構成を示す図である。
図３中に示すように、本実施形態の表面硬化処理装置１の構成は、水素濃度検出配管２２及び開閉弁１０の構成と、配管温度制御手段４６を備えている点を除き、上述した第一実施形態と同様であるため、以下の説明は、配管温度制御手段４６に関する部分を中心に記載する。なお、図３中では、処理炉２、水素濃度検出手段４、水素濃度検出配管２２、開閉弁１０及び配管温度制御手段４６以外の図示を省略している。 (Second embodiment)
Hereinafter, a second embodiment of the present invention (hereinafter referred to as “the present embodiment”) will be described with reference to the drawings.
(Constitution)
FIG. 3 is a diagram showing a configuration of the surface hardening processing apparatus 1 of the present embodiment.
As shown in FIG. 3, the configuration of the surface hardening treatment apparatus 1 of the present embodiment is the same as that described above except that the configuration of the hydrogen concentration detection pipe 22 and the on-off valve 10 and the pipe temperature control means 46 are provided. Since it is the same as that of one embodiment, the following description will be described focusing on the portion related to the piping temperature control means 46. 3, illustrations other than the processing furnace 2, the hydrogen concentration detection means 4, the hydrogen concentration detection pipe 22, the on-off valve 10, and the pipe temperature control means 46 are omitted.

水素濃度検出配管２２は、処理炉２と水素濃度検出手段４とを連通する第一配管２２ａと、処理炉２と第一配管２２ａとを連通する第二配管２２ｂと、第一配管２２ａと連通する第三配管２２ｃから形成されている。
開閉弁１０は、第一配管２２ａに介装する第一開閉弁１０ａと、第二配管２２ｂに介装する第二開閉弁１０ｂと、第三配管２２ｃに介装する第三開閉弁１０ｃから形成されている。
配管温度制御手段４６は、線状のヒーターを用いて形成されており、水素濃度検出配管２２の温度を制御する。 The hydrogen concentration detection pipe 22 communicates with the first pipe 22a that connects the processing furnace 2 and the hydrogen concentration detection means 4, the second pipe 22b that connects the processing furnace 2 and the first pipe 22a, and the first pipe 22a. The third pipe 22c is formed.
The on-off valve 10 is formed from a first on-off valve 10a interposed in the first pipe 22a, a second on-off valve 10b interposed in the second pipe 22b, and a third on-off valve 10c interposed in the third pipe 22c. Has been.
The pipe temperature control means 46 is formed using a linear heater, and controls the temperature of the hydrogen concentration detection pipe 22.

具体的には、配管温度制御手段４６は、水素濃度検出配管２２内で炉内ガスが固体として析出しないように、炉内導入ガスの種類に応じて、水素濃度検出配管２２の温度を、２５〜４５０℃の範囲内に制御する。
具体的には、配管温度制御手段４６は、表面硬化処理がガス窒化処理であり、炉内導入ガスの種類が、処理炉２内で塩化水素ガスが発生するようなガスである場合は、水素濃度検出配管２２の温度を３４０〜４５０℃の範囲内に制御する。
また、配管温度制御手段４６は、表面硬化処理がガス軟窒化処理である場合は、水素濃度検出配管２２の温度を６０〜１００℃の範囲内に制御する。
その他の構成は、上述した第一実施形態と同様である。 Specifically, the pipe temperature control means 46 sets the temperature of the hydrogen concentration detection pipe 22 to 25 according to the type of the gas introduced into the furnace so that the furnace gas does not precipitate as a solid in the hydrogen concentration detection pipe 22. Control within the range of ~ 450 ° C.
Specifically, the pipe temperature control means 46 uses hydrogen gas when the surface hardening process is a gas nitriding process and the type of gas introduced into the furnace is such that hydrogen chloride gas is generated in the processing furnace 2. The temperature of the concentration detection pipe 22 is controlled within a range of 340 to 450 ° C.
Moreover, the piping temperature control means 46 controls the temperature of the hydrogen concentration detection piping 22 within the range of 60-100 degreeC, when a surface hardening process is a gas soft nitriding process.
Other configurations are the same as those of the first embodiment described above.

（動作）
以下、図３を参照して、被処理品の表面硬化処理を行う際の、本実施形態の表面硬化処理装置１の動作について説明する。なお、本実施形態の表面硬化処理装置１の動作は、配管温度制御手段４６が行う動作を除き、上述した第一実施形態と同様であるため、以下の説明は、配管温度制御手段４６が行う動作を中心に記載する。また、以下の説明は、表面硬化処理をガス窒化処理とした場合について記載する。 (Operation)
Hereinafter, with reference to FIG. 3, operation | movement of the surface hardening processing apparatus 1 of this embodiment at the time of performing the surface hardening process of to-be-processed goods is demonstrated. The operation of the surface hardening processing apparatus 1 of the present embodiment is the same as that of the first embodiment described above except for the operation performed by the pipe temperature control means 46. Therefore, the following description is performed by the pipe temperature control means 46. The operation will be mainly described. Moreover, the following description describes the case where the surface hardening treatment is a gas nitriding treatment.

表面硬化処理を行う際には、処理炉２内に被処理品Ｓを配置した後、混合ガスを処理炉２内へ導入し、処理炉２内の雰囲気を攪拌する。
このとき、配管温度制御手段４６は、表面硬化処理がガス窒化処理であり、炉内導入ガスの種類が、処理炉２内で塩化水素ガスが発生するようなガスであるため、水素濃度検出配管２２の温度を３４０〜４５０℃の範囲内に制御する。 When performing the surface hardening process, after the article to be processed S is arranged in the processing furnace 2, the mixed gas is introduced into the processing furnace 2, and the atmosphere in the processing furnace 2 is stirred.
At this time, the pipe temperature control means 46 has a hydrogen concentration detection pipe because the surface hardening process is a gas nitriding process and the type of gas introduced into the furnace is such that hydrogen chloride gas is generated in the processing furnace 2. The temperature of 22 is controlled within the range of 340 to 450 ° C.

配管温度制御手段４６が、水素濃度検出配管２２の温度を３４０〜４５０℃の範囲内に制御すると、炉内ガスが水素濃度検出配管２２内で固体として析出することを抑制した状態で、表面硬化処理を行うことが可能となる。これにより、水素濃度検出手段４の検出精度の低下を抑制し、水素濃度検出手段４の検出精度を長期間に亘って維持した状態で、表面硬化処理を行うことが可能となる。   When the pipe temperature control means 46 controls the temperature of the hydrogen concentration detection pipe 22 within the range of 340 to 450 ° C., surface hardening is performed in a state where the in-furnace gas is prevented from being precipitated as a solid in the hydrogen concentration detection pipe 22. Processing can be performed. Thereby, it becomes possible to perform the surface hardening process in a state where the detection accuracy of the hydrogen concentration detection unit 4 is suppressed from being lowered and the detection accuracy of the hydrogen concentration detection unit 4 is maintained for a long period of time.

（第二実施形態の効果）
以下、本実施形態の効果を記載する。
（１）本実施形態の表面硬化処理装置１では、配管温度制御手段４６が、炉内導入ガスの種類に応じて、水素濃度検出配管２２の温度を２５〜４５０℃の範囲内に制御することにより、炉内ガスが水素濃度検出配管２２内で固体として析出することを抑制する。 (Effect of the second embodiment)
Hereinafter, effects of the present embodiment will be described.
(1) In the surface hardening treatment apparatus 1 of the present embodiment, the pipe temperature control means 46 controls the temperature of the hydrogen concentration detection pipe 22 within a range of 25 to 450 ° C. according to the type of gas introduced into the furnace. This suppresses the in-furnace gas from being precipitated as a solid in the hydrogen concentration detection pipe 22.

このため、ガス窒化処理やガス軟窒化処理等、塩化アンモニウムや炭酸アンモニウムが水素濃度検出配管２２内で析出するおそれのある表面硬化処理において、水素濃度検出配管２２内における塩化アンモニウムや炭酸アンモニウムの析出を抑制することが可能となる。
その結果、炭酸アンモニウムの析出や処理炉２内における塩化水素の発生を抑制することが可能となるため、水素濃度検出手段４の検出精度を長期間に亘って維持することが可能となる。 Therefore, precipitation of ammonium chloride or ammonium carbonate in the hydrogen concentration detection pipe 22 in a surface hardening process in which ammonium chloride or ammonium carbonate may deposit in the hydrogen concentration detection pipe 22 such as gas nitriding treatment or gas soft nitriding treatment. Can be suppressed.
As a result, precipitation of ammonium carbonate and generation of hydrogen chloride in the processing furnace 2 can be suppressed, so that the detection accuracy of the hydrogen concentration detection means 4 can be maintained over a long period of time.

（第一実施例）
上述した第一実施形態の表面硬化処理装置（以下、「第一発明例」と記載する）により表面硬化処理を行った場合と、第一実施形態の表面硬化処理装置とは構成が異なる装置（以下、「第一比較例」と記載する）により表面硬化処理を行った場合に対し、処理炉内の雰囲気を制御した。
なお、第一発明例及び第一比較例共に、処理炉として、ピット型ガス窒化炉（処理重量：５０ｋｇ／ｇｒｏｓｓ）を備え、処理炉内の温度を５７０℃とし、アンモニアガスの処理炉への導入量を、マスフローコントローラにより、１．６ｍ３／ｈに制御し、また、窒素ガスの処理炉への導入量を、マスフローコントローラにより、０．４ｍ３／ｈに制御して、窒化ポテンシャルＫＮが３．３となるように、ガス窒化処理を行った。 (First Example)
When the surface hardening treatment is performed by the surface hardening treatment device of the first embodiment described above (hereinafter referred to as “first invention example”), the surface hardening treatment device of the first embodiment has a different configuration ( Hereinafter, the atmosphere in the processing furnace was controlled with respect to the case where the surface hardening treatment was performed according to “first comparative example”.
Both the first invention example and the first comparative example are provided with a pit type gas nitriding furnace (processing weight: 50 kg / gross) as a processing furnace, the temperature in the processing furnace is set to 570 ° C., and the ammonia gas is supplied to the processing furnace. The introduction amount is controlled to 1.6 m 3 / h by the mass flow controller, and the introduction amount of nitrogen gas to the processing furnace is controlled to 0.4 m 3 / h by the mass flow controller, and the nitriding potential K N The gas nitridation process was performed so as to be 3.3.

ここで、第一発明例では、ＮＨ３：Ｎ２＝８０：２０という混合ガスの混合比率を基にして、ガス導入量制御手段により、窒化ポテンシャルＫＮが３．０となるための水素濃度の設定値と、水素濃度検出手段により検出した炉内ガスの水素濃度とを比較し、アンモニアガス及び窒素ガスのマスフローコントローラに対して、それぞれ、設定炉内ガス混合比率であるＮＨ３：Ｎ２＝８０：２０を保持した状態で、アンモニアガス及び窒素ガスの処理炉内への合計導入量を制御することにより、窒化ポテンシャルＫＮを制御した。 Here, in the first invention example, the hydrogen concentration at which the nitriding potential K N becomes 3.0 by the gas introduction amount control means based on the mixing ratio of the mixed gas of NH 3 : N 2 = 80: 20. And the hydrogen concentration of the in-furnace gas detected by the hydrogen concentration detecting means, and NH 3 : N 2, which is a set in-furnace gas mixing ratio, for the ammonia gas and nitrogen gas mass flow controllers, respectively. While maintaining = 80: 20, the nitriding potential K N was controlled by controlling the total amount of ammonia gas and nitrogen gas introduced into the processing furnace.

一方、第一比較例では、窒素ガスの処理炉内への導入量のみを制御することにより、窒化ポテンシャルＫＮを制御した。
以下、炉内ガスの水素濃度（炉内水素濃度）、炉内ガスのアンモニア濃度（炉内アンモニア濃度）、処理炉内の雰囲気の窒化ポテンシャル（窒化ポテンシャルＫＮ）を測定した結果を、表１に示す。 On the other hand, in the first comparative example, the nitriding potential K N was controlled by controlling only the amount of nitrogen gas introduced into the processing furnace.
Table 1 shows the results of measuring the hydrogen concentration of the furnace gas (furnace hydrogen concentration), the ammonia concentration of the furnace gas (furnace ammonia concentration), and the nitriding potential (nitriding potential K N ) of the atmosphere in the processing furnace. Shown in

Figure 0005629436
Figure 0005629436

表１中に示されているように、第一発明例では、窒化ポテンシャルＫＮを、３．３
と、精度良く制御することができた。また、炉内水素濃度を２７．４％、炉内アンモニア濃度を４７．２％に、それぞれ、制御することが可能であった。
これに対し、第一比較例では、窒化ポテンシャルＫＮの制御が不可能であった。また、炉内水素濃度を２７．４％に制御することが可能であったものの、炉内アンモニア濃度は計算不能であった。
これは、第一比較例では、水素濃度検出手段により炉内ガスの水素濃度のみを検出することは可能であったが、炉内ガス中における炉内ガス組成が不明であったため、検出した水素濃度からアンモニア濃度を求めることができず、窒化ポテンシャルＫＮの演算が不可能であったためである。 As shown in Table 1, in the first invention example, the nitriding potential K N is set to 3.3.
It was possible to control with high accuracy. It was also possible to control the furnace hydrogen concentration to 27.4% and the furnace ammonia concentration to 47.2%, respectively.
In contrast, in the first comparative example, it was impossible to control the nitride potential K N. In addition, although the furnace hydrogen concentration could be controlled to 27.4%, the furnace ammonia concentration could not be calculated.
In the first comparative example, it was possible to detect only the hydrogen concentration of the in-furnace gas by the hydrogen concentration detecting means, but the detected gas concentration was unknown because the in-furnace gas composition in the in-furnace gas was unknown. It can not be obtained ammonia concentration from the concentration, because it was impossible to calculation nitride potential K N.

（第二実施例）
上述した第二実施形態の表面硬化処理装置（以下、「第二発明例」と記載する）により表面硬化処理を行った場合と、第二実施形態の表面硬化処理装置とは構成が異なる装置（以下、「第二比較例」と記載する）により表面硬化処理を行った場合に対し、処理炉内の雰囲気を制御した。 (Second embodiment)
When the surface hardening treatment is performed by the surface hardening treatment device of the second embodiment described above (hereinafter referred to as “second invention example”), the surface hardening treatment device of the second embodiment has a different configuration ( Hereinafter, the atmosphere in the processing furnace was controlled with respect to the case where the surface hardening treatment was performed according to “second comparative example”.

ここで、図４を参照して、第二比較例の表面硬化処理装置１の構成を説明する。
図４は、比較例の表面硬化処理装置１の構成を示す図である。
図４中に示すように、比較例の表面硬化処理装置１は、開閉弁を備えていない点を除き、第一発明例（図１参照）と同様の構成である。なお、図４中では、処理炉２及び水素濃度検出手段４以外の図示を省略している。 Here, with reference to FIG. 4, the structure of the surface hardening processing apparatus 1 of a 2nd comparative example is demonstrated.
FIG. 4 is a diagram illustrating a configuration of the surface hardening treatment apparatus 1 of the comparative example.
As shown in FIG. 4, the surface hardening treatment apparatus 1 of the comparative example has the same configuration as the first invention example (see FIG. 1) except that it does not include an on-off valve. In FIG. 4, illustrations other than the processing furnace 2 and the hydrogen concentration detection means 4 are omitted.

なお、第二発明例及び第二比較例共に、処理炉として、バッチ型ガス軟窒化炉（処理重量：６００ｋｇ／ｇｒｏｓｓ）を備え、処理炉内の温度を５８０℃とし、アンモニアガスの処理炉への導入量を８ｍ３／ｈ、窒素ガスの処理炉への導入量を５ｍ３／ｈ、二酸化炭素ガスの処理炉への導入量を０．４ｍ３／ｈに制御して、３時間のガス軟窒化処理を、５ロット／日で５日間／週の期間行った。 Both the second invention example and the second comparative example are provided with a batch type gas nitrocarburizing furnace (processing weight: 600 kg / gross) as a processing furnace, the temperature in the processing furnace is set to 580 ° C., and the process proceeds to an ammonia gas processing furnace. The amount of gas introduced is 8 m 3 / h, the amount of nitrogen gas introduced into the processing furnace is 5 m 3 / h, and the amount of carbon dioxide gas introduced into the processing furnace is controlled to 0.4 m 3 / h for 3 hours. Soft nitriding was performed at 5 lots / day for a period of 5 days / week.

ここで、第二発明例では、配管温度制御手段４６により、水素濃度検出配管２２及び開閉弁１０の温度を６０℃に制御し、さらに、水素濃度検出手段４付近の温度を８０℃に制御した。これに加え、第二発明例では、被処理品の温度が５８０℃に到達してから冷却する前の、ガス軟窒化処理期間のみ、第一開閉弁１０ａ及び第二開閉弁１０ｂを連通状態として、水素濃度検出手段４により炉内ガスの水素濃度を検出した。また、被処理品の冷却中は、第一開閉弁１０ａを閉鎖状態とし、第二開閉弁１０ｂ及び第三開閉弁１０ｃを連通状態として、窒素ガスを５分間流すことにより、水素濃度検出配管２２及び水素濃度検出手段４のセンサ部をパージした。その後、第二開閉弁１０ｂ及び第三開閉弁１０ｃを閉鎖状態として、センサ部と、第一開閉弁１０ａ、第二開閉弁１０ｂ及び第三開閉弁１０ｃにより囲まれた水素濃度検出配管２２内の空間を窒素ガスで封入しておき、この状態を、次に行う表面硬化処理における処理炉２内の昇温が完了するまで保持した。   Here, in the second invention example, the temperature of the hydrogen concentration detection pipe 22 and the on-off valve 10 is controlled to 60 ° C. by the pipe temperature control means 46, and the temperature near the hydrogen concentration detection means 4 is controlled to 80 ° C. . In addition to this, in the second invention example, the first on-off valve 10a and the second on-off valve 10b are brought into the communication state only during the gas soft nitriding treatment period after the temperature of the article to be processed reaches 580 ° C. and before cooling. The hydrogen concentration in the furnace gas was detected by the hydrogen concentration detection means 4. Further, while the product to be processed is cooled, the first on-off valve 10a is closed, the second on-off valve 10b and the third on-off valve 10c are in communication, and nitrogen gas is allowed to flow for 5 minutes, thereby allowing the hydrogen concentration detection pipe 22 to flow. And the sensor part of the hydrogen concentration detection means 4 was purged. Thereafter, the second on-off valve 10b and the third on-off valve 10c are closed, and the hydrogen concentration detection pipe 22 surrounded by the sensor unit and the first on-off valve 10a, the second on-off valve 10b, and the third on-off valve 10c is provided. The space was sealed with nitrogen gas, and this state was maintained until the temperature increase in the processing furnace 2 in the next surface hardening treatment was completed.

一方、第二比較例では、水素濃度検出手段４のセンサ部付近の温度を４０℃に制御した。
以下、水素濃度検出配管２２及び水素濃度検出手段４のセンサ部の汚染状況（接続配管及びセンサー部の汚染状況）と、水素濃度検出手段４が検出した水素濃度の標準水素ガスによる誤差のチェック結果（熱伝導度センサー値の標準水素ガスによる誤差チェック結果）を測定した結果を、表２に示す。 On the other hand, in the second comparative example, the temperature in the vicinity of the sensor portion of the hydrogen concentration detection means 4 was controlled to 40 ° C.
Hereinafter, the contamination status of the sensor part of the hydrogen concentration detection pipe 22 and the hydrogen concentration detection means 4 (contamination status of the connection pipe and the sensor part) and the error check result of the standard hydrogen gas of the hydrogen concentration detected by the hydrogen concentration detection means 4 Table 2 shows the measurement results of the error check result of the thermal conductivity sensor value using standard hydrogen gas.

Figure 0005629436
Figure 0005629436

表２中に示されているように、第二比較例では、１ロット目から水素濃度検出配管２２及び水素濃度検出手段４のセンサ部に析出した炭酸アンモニウムと被処理品からの油分や汚れが付着し始めた。また、３ロットが終了した時点において、標準水素ガスにより、水素濃度検出手段４の精度をチェックしたところ、フルスケールに対して約１０％の誤差が生じていたことが確認された。   As shown in Table 2, in the second comparative example, the ammonium carbonate deposited on the hydrogen concentration detection pipe 22 and the sensor part of the hydrogen concentration detection means 4 from the first lot and the oil and dirt from the product to be processed Began to stick. Further, when the accuracy of the hydrogen concentration detecting means 4 was checked with the standard hydrogen gas at the time when the three lots were completed, it was confirmed that an error of about 10% had occurred relative to the full scale.

これに対し、第二発明例では、１０ロットを処理した後においても、水素濃度検出配管２２、開閉弁１０及び水素濃度検出手段４のセンサ部に、炭酸アンモニウムの析出は発生していなかった。また、標準水素ガスにより、水素濃度検出手段４の精度をチェックしたところ、フルスケールに対して０．５％以内の誤差しか生じていないことが確認された。さらに、第二発明例では、４ヶ月経過した後に、標準水素ガスにより、水素濃度検出手段４の精度をチェックしたところ、フルスケールに対して０．５％以内の誤差しか生じていないことが確認された。   In contrast, in the second invention example, ammonium carbonate was not deposited on the hydrogen concentration detection pipe 22, the on-off valve 10, and the sensor portion of the hydrogen concentration detection means 4 even after 10 lots were processed. Further, when the accuracy of the hydrogen concentration detecting means 4 was checked with the standard hydrogen gas, it was confirmed that only an error of 0.5% or less was generated with respect to the full scale. Furthermore, in the second invention example, the accuracy of the hydrogen concentration detection means 4 was checked with standard hydrogen gas after 4 months had passed, and it was confirmed that there was only an error of 0.5% or less with respect to full scale. It was done.

（第三実施例）
上述した第一実施形態の表面硬化処理装置（以下、「第三発明例」と記載する）により表面硬化処理を行った場合と、第一実施形態の表面硬化処理装置とは構成が異なる装置（以下、「第三比較例」と記載する）により表面硬化処理を行った場合に対し、処理炉内の雰囲気を制御した。 (Third embodiment)
When the surface hardening treatment is performed by the surface hardening treatment device of the first embodiment described above (hereinafter referred to as “third invention example”), the surface hardening treatment device of the first embodiment has a different configuration ( Hereinafter, the atmosphere in the processing furnace was controlled with respect to the case where the surface hardening treatment was performed according to “third comparative example”.

なお、第三発明例及び第三比較例共に、処理炉として、バッチ型ガス軟窒化炉（処理重量：６００ｋｇ／ｇｒｏｓｓ）を備え、処理炉内の温度を５８０℃とし、アンモニアガスの処理炉への導入量を８ｍ３／ｈ、窒素ガスの処理炉への導入量を５ｍ３／ｈ、二酸化炭素ガスの処理炉への導入量を０．４ｍ３／ｈに制御して、３時間のガス軟窒化処理を、被処理品（Ｓ４５Ｃ材及びＳＣＭ４４０材）に対して行った。 Both the third invention example and the third comparative example are equipped with a batch type gas soft nitriding furnace (processing weight: 600 kg / gross) as the processing furnace, the temperature in the processing furnace is set to 580 ° C., and the ammonia gas processing furnace The amount of gas introduced is 8 m 3 / h, the amount of nitrogen gas introduced into the processing furnace is 5 m 3 / h, and the amount of carbon dioxide gas introduced into the processing furnace is controlled to 0.4 m 3 / h for 3 hours. Soft nitriding was performed on the products to be processed (S45C material and SCM440 material).

ここで、第三発明例では、処理炉内の昇温が完了した後、３時間のガス軟窒化処理を行う間は、窒化ポテンシャルＫＮが３．１（Ｎ２：２３％，ＮＨ３：３５％）となるように、アンモニアガス及び窒素ガスの処理炉内への導入量を保持した状態で、アンモニアガス及び窒素ガスの処理炉内への合計導入量を制御することにより、処理炉内の雰囲気を制御した。 Here, in the third invention example, the nitriding potential K N is 3.1 (N 2 : 23%, NH 3 : during the gas soft nitriding treatment for 3 hours after the temperature rise in the processing furnace is completed. 35%), by controlling the total introduction amount of ammonia gas and nitrogen gas into the processing furnace while maintaining the introduction amount of ammonia gas and nitrogen gas into the treatment furnace. Controlled atmosphere.

一方、第三比較例では、処理炉内の昇温が完了した後、３時間のガス軟窒化処理を行う間は、処理炉内の雰囲気を制御せずに、アンモニアガス、窒素ガス及び二酸化炭素ガスの処理炉への導入量を、それぞれ、上記の値に保持した。
以下、炉内導入ガスの使用量（ガス使用量）、表面硬化処理装置の窒化性能（窒化性能）を測定した結果を、表３に示す。 On the other hand, in the third comparative example, during the gas soft nitriding treatment for 3 hours after the temperature increase in the processing furnace was completed, the atmosphere in the processing furnace was not controlled, and ammonia gas, nitrogen gas, and carbon dioxide. The amount of gas introduced into the processing furnace was maintained at the above value.
Table 3 shows the results of measuring the amount of gas introduced into the furnace (the amount of gas used) and the nitriding performance (nitriding performance) of the surface hardening apparatus.

Figure 0005629436
Figure 0005629436

表３中に示されているように、第三発明例では、表面硬化処理装置の窒化性能を第三比較例と同様に保持した状態で、炉内導入ガスの使用量を大幅に削減することが可能となり、表面硬化処理に要するランニングコストを減少させて、経済的効果を達成するとともに、大気中へのガス排出量を減少させて、環境の悪化を抑制することが可能となることが確認された。   As shown in Table 3, in the third invention example, the use amount of the introduced gas in the furnace should be greatly reduced while maintaining the nitriding performance of the surface hardening processing apparatus as in the third comparative example. It is possible to reduce the running cost required for the surface hardening treatment, achieve economic effects, reduce the amount of gas discharged into the atmosphere, and suppress the deterioration of the environment. It was done.

（第四実施例）
上述した第二実施形態の表面硬化処理装置と同様の各種センサ及び配管温度制御手段を備え、表面硬化処理として真空浸炭処理を行う構成の表面硬化処理装置（以下、「第四発明例」と記載する）により表面硬化処理を行った場合と、第二比較例と同様の構成を有する装置（以下、「第四比較例」と記載する）により表面硬化処理を行った場合に対し、処理炉内の雰囲気を制御した。 (Fourth embodiment)
Surface hardening treatment apparatus (hereinafter referred to as “fourth invention example”) having various sensors and pipe temperature control means similar to those of the surface hardening treatment apparatus of the second embodiment described above and configured to perform vacuum carburization treatment as surface hardening treatment. In the processing furnace, compared to the case where the surface hardening treatment is performed by the above and the case where the surface hardening treatment is performed by an apparatus having the same configuration as the second comparative example (hereinafter referred to as “fourth comparative example”). Controlled atmosphere.

なお、第四発明例及び第四比較例共に、処理炉として、バッチ型真空浸炭炉（処理重量：６００ｋｇ／ｇｒｏｓｓ）を備え、まず、処理炉内の温度を９５０℃として、１５ｍｉｎの浸炭、３０ｍｉｎの拡散、７ｍｉｎの浸炭、４５ｍｉｎの拡散を順に行い、その後、処理炉内の温度を８５０℃として、３０ｍｉｎの保持を行った後、６０℃の油中において、被処理品を焼入れした。さらに、処理炉内の圧力を１０６７Ｐａとして、２時間の間、プロパンガスの処理炉への導入量を３０Ｌ／ｍ、窒素ガスの処理炉への導入量を２０Ｌ／ｍに制御して、２ロット／日で５日間／週の期間、真空浸炭処理を行った。
ここで、第四発明例では、配管温度制御手段４６により、水素濃度検出配管２２及び開閉弁１０の温度を６０℃に制御し、さらに、水素濃度検出手段４付近の温度を８０℃に制御した。 In addition, both the fourth invention example and the fourth comparative example are provided with a batch type vacuum carburizing furnace (processing weight: 600 kg / gross) as a processing furnace. First, the temperature in the processing furnace is set to 950 ° C., carburizing for 15 min, 30 min , Carburization for 7 min, and diffusion for 45 min were sequentially performed. Thereafter, the temperature in the processing furnace was set to 850 ° C. and held for 30 min, and then the product to be processed was quenched in oil at 60 ° C. Furthermore, the pressure in the processing furnace was set to 1067 Pa, and the amount of propane gas introduced into the processing furnace was controlled to 30 L / m and the amount of nitrogen gas introduced into the processing furnace was controlled to 20 L / m for 2 hours. The vacuum carburization treatment was performed for 5 days / week.
Here, in the fourth invention example, the temperature of the hydrogen concentration detection pipe 22 and the on-off valve 10 is controlled to 60 ° C. by the pipe temperature control means 46, and the temperature near the hydrogen concentration detection means 4 is controlled to 80 ° C. .

一方、第四比較例では、水素濃度検出手段４のセンサ部付近の温度を４０℃に制御した。
以下、水素濃度検出配管２２及び水素濃度検出手段４のセンサ部の汚染状況（接続配管及びセンサー部の汚染状況）と、水素濃度検出手段４が検出した水素濃度の標準水素ガスによる誤差のチェック結果（熱伝導度センサー値の標準水素ガスによる誤差チェック結果）を測定した結果を、表４に示す。 On the other hand, in the fourth comparative example, the temperature in the vicinity of the sensor portion of the hydrogen concentration detection means 4 was controlled to 40 ° C.
Hereinafter, the contamination status of the sensor part of the hydrogen concentration detection pipe 22 and the hydrogen concentration detection means 4 (contamination status of the connection pipe and the sensor part) and the error check result of the standard hydrogen gas of the hydrogen concentration detected by the hydrogen concentration detection means 4 Table 4 shows the results of measuring (error check result of standard conductivity of thermal conductivity sensor value).

Figure 0005629436
Figure 0005629436

表４中に示されているように、第四比較例では、１ロット目から水素濃度検出配管２２及び水素濃度検出手段４のセンサ部に、煤やタールが付着し始めた。また、１０ロットが終了した時点において、標準水素ガスにより、水素濃度検出手段４の精度をチェックしたところ、フルスケールに対して約２０％の誤差が生じていたことが確認された。   As shown in Table 4, in the fourth comparative example, soot and tar began to adhere to the hydrogen concentration detection pipe 22 and the sensor part of the hydrogen concentration detection means 4 from the first lot. Further, when the accuracy of the hydrogen concentration detecting means 4 was checked with standard hydrogen gas at the time when 10 lots were completed, it was confirmed that an error of about 20% with respect to the full scale had occurred.

これに対し、第四発明例では、１０ロットを処理した後においても、水素濃度検出配管２２、開閉弁１０及び水素濃度検出手段４のセンサ部に、煤やタールの付着は発生していなかった。また、１０ロットが終了した時点において、標準水素ガスにより、水素濃度検出手段４の精度をチェックしたところ、フルスケールに対して０．５％以内の誤差しか生じていないことが発見された。さらに、第四発明例では、３ヶ月経過した後に、標準水素ガスにより、水素濃度検出手段４の精度をチェックしたところ、フルスケールに対して０．５％以内の誤差しか生じていないことが確認された。   On the other hand, in the fourth invention example, no soot or tar adhered to the hydrogen concentration detection pipe 22, the on-off valve 10 and the sensor part of the hydrogen concentration detection means 4 even after processing 10 lots. . Further, when the accuracy of the hydrogen concentration detecting means 4 was checked with standard hydrogen gas at the time when 10 lots were completed, it was found that only an error of 0.5% or less with respect to the full scale was generated. Furthermore, in the fourth invention example, when the accuracy of the hydrogen concentration detection means 4 was checked with standard hydrogen gas after 3 months had passed, it was confirmed that there was only an error of 0.5% or less with respect to full scale. It was done.

本発明に係る表面硬化処理装置及び表面硬化処理方法は、金属材料からなる、自動車、建設機械、各種産業機械等の部品や金型に対する、窒化、軟窒化、浸炭、浸炭窒化等の表面硬化処理に利用することが可能である。   The surface hardening treatment apparatus and the surface hardening treatment method according to the present invention are a surface hardening treatment such as nitriding, soft nitriding, carburizing, carbonitriding, etc., for parts and molds of automobiles, construction machines, various industrial machines, etc. made of a metal material. It is possible to use it.

１ 表面硬化処理装置
２ 処理炉
４ 水素濃度検出手段
６ 調節計
８ 記録計
１０ 開閉弁（第一開閉弁１０ａ、第二開閉弁１０ｂ、第三開閉弁１０ｃ）
１２ 開閉弁切換え制御手段
１４ 炉内導入ガス供給部
１６ 攪拌ファン
１８ 攪拌ファン駆動モータ
２０ 炉内温度計測手段
２２ 水素濃度検出配管（第一配管２２ａ、第二配管２２ｂ、第三配管２２ｃ）
２４ 炉内ガス組成演算手段
２６ ガス導入量制御手段
２８ 第一炉内導入ガス供給部
３０ 第一炉内導入ガス供給量制御部
３２ 第一供給弁
３４ 第一炉内導入ガス流量計
３６ 第二炉内導入ガス供給部
３８ 第二炉内導入ガス供給量制御部
４０ 第二供給弁
４２ 第二炉内導入ガス流量計
４４ 炉内導入ガス導入配管
４６ 配管温度制御手段
Ｓ 被処理品 DESCRIPTION OF SYMBOLS 1 Surface hardening processing apparatus 2 Processing furnace 4 Hydrogen concentration detection means 6 Controller 8 Recorder 10 On-off valve (1st on-off valve 10a, 2nd on-off valve 10b, 3rd on-off valve 10c)
12 On-off valve switching control means 14 Furnace introduction gas supply unit 16 Stirring fan 18 Stirring fan drive motor 20 Furnace temperature measurement means 22 Hydrogen concentration detection pipe (first pipe 22a, second pipe 22b, third pipe 22c)
24 In-furnace gas composition calculation means 26 Gas introduction amount control means 28 First furnace introduction gas supply section 30 First furnace introduction gas supply quantity control section 32 First supply valve 34 First furnace introduction gas flow meter 36 Second Furnace introduction gas supply unit 38 Second furnace introduction gas supply amount control unit 40 Second supply valve 42 Second furnace introduction gas flow meter 44 Furnace introduction gas introduction pipe 46 Pipe temperature control means S Processed product

Claims (4)

処理炉内で水素を発生するガスとしてはアセチレンガスのみを含むとともに、その他のガスとして窒素ガスを含む炉内導入ガスを前記処理炉内へ導入して、前記処理炉内に配置した被処理品の表面硬化処理として真空浸炭処理を行う表面硬化処理装置であって、
前記処理炉内の炉内ガスの熱伝導度に基づいて、前記炉内ガスの水素濃度を検出する水素濃度検出手段と、
前記水素濃度検出手段が検出した水素濃度に基づいて前記アセチレンガスの炉内濃度を演算し、当該演算した炉内濃度の演算値に基づいて前記炉内ガスの組成である炉内ガス組成を演算する炉内ガス組成演算手段と、
前記炉内ガス組成演算手段が演算した炉内ガス組成と予め設定した設定炉内ガス混合比率に応じて、前記炉内ガス組成が前記設定炉内ガス混合比率となるように、前記複数種類の前記炉内導入ガスの前記処理炉内への導入量の比率である炉内導入ガス流量比率を一定値に保持した状態で前記複数種類の前記炉内導入ガスの前記処理炉内への合計導入量を制御する第一の制御と、前記炉内導入ガス流量比率が変化するように前記複数種類の炉内導入ガスの導入量を個別に制御する第二の制御と、の両者を実行可能であるとともに、同時にはいずれか一方の制御のみを選択的に行うガス導入量制御手段と、を備えることを特徴とする表面硬化処理装置。 As a gas for generating hydrogen in the processing furnace, only the acetylene gas is contained, and an in-furnace introduction gas containing nitrogen gas as the other gas is introduced into the processing furnace, and the article to be processed is arranged in the processing furnace. a surface hardening processing apparatus for performing a vacuum carburizing treatment as the surface hardening treatment,
Based on the thermal conductivity of the furnace gas in the processing furnace, hydrogen concentration detection means for detecting the hydrogen concentration of the furnace gas;
Calculate the in-furnace concentration of the acetylene gas based on the hydrogen concentration detected by the hydrogen concentration detecting means, and calculate the in-furnace gas composition which is the composition of the in-furnace gas based on the calculated value of the calculated in-furnace concentration An in-furnace gas composition calculating means,
In accordance with the in-furnace gas composition calculated by the in-furnace gas composition calculating means and the preset in-furnace gas mixing ratio, the plurality of types of the in-furnace gas composition become the set in-furnace gas mixing ratio. total Previous Symbol the processing furnace of a plurality of types of the furnace gas introduced while holding the furnace introduced gas flow ratio is the ratio of the introduction amount into the processing furnace of the furnace gas introduced to a constant value Both the first control for controlling the introduction amount and the second control for individually controlling the introduction amounts of the plurality of types of in-furnace introduction gases so that the in-furnace introduction gas flow rate ratio can be changed. And a gas introduction amount control means that selectively controls only one of them at the same time. 処理炉内で水素を発生するガスとしてはアンモニアガスのみを含む複数種類の炉内導入ガスを前記処理炉内へ導入して、前記処理炉内に配置した被処理品の表面硬化処理としてガス窒化処理またはガス軟窒化処理を行う表面硬化処理装置であって、
前記処理炉内の炉内ガスの熱伝導度に基づいて、前記炉内ガスの水素濃度を検出する水素濃度検出手段と、
前記水素濃度検出手段が検出した水素濃度に基づいて前記アンモニアガスの炉内濃度を演算し、当該演算した炉内濃度の演算値に基づいて前記炉内ガスの組成である炉内ガス組成を演算する炉内ガス組成演算手段と、
前記炉内ガス組成演算手段が演算した炉内ガス組成と予め設定した設定炉内ガス混合比率に応じて、前記炉内ガス組成が前記設定炉内ガス混合比率となるように、前記複数種類の前記炉内導入ガスの前記処理炉内への導入量の比率である炉内導入ガス流量比率を一定値に保持した状態で前記複数種類の前記炉内導入ガスの前記処理炉内への合計導入量を制御する第一の制御と、前記炉内導入ガス流量比率が変化するように前記複数種類の炉内導入ガスの導入量を個別に制御する第二の制御と、の両者を実行可能であるとともに、同時にはいずれか一方の制御のみを選択的に行うガス導入量制御手段と、を備えることを特徴とする表面硬化処理装置。 As a gas for generating hydrogen in the processing furnace, a plurality of types of in-furnace introduction gases containing only ammonia gas are introduced into the processing furnace, and gas nitriding is performed as a surface hardening treatment of the article to be processed disposed in the processing furnace. A surface hardening treatment apparatus for performing treatment or gas soft nitriding treatment,
Based on the thermal conductivity of the furnace gas in the processing furnace, hydrogen concentration detection means for detecting the hydrogen concentration of the furnace gas;
The in-furnace concentration of the ammonia gas is calculated based on the hydrogen concentration detected by the hydrogen concentration detection means, and the in-furnace gas composition that is the composition of the in-furnace gas is calculated based on the calculated value of the calculated in-furnace concentration. An in-furnace gas composition calculating means,
In accordance with the in-furnace gas composition calculated by the in-furnace gas composition calculating means and the preset in-furnace gas mixing ratio, the plurality of types of the in-furnace gas composition become the set in-furnace gas mixing ratio. total Previous Symbol the processing furnace of a plurality of types of the furnace gas introduced while holding the furnace introduced gas flow ratio is the ratio of the introduction amount into the processing furnace of the furnace gas introduced to a constant value Both the first control for controlling the introduction amount and the second control for individually controlling the introduction amounts of the plurality of types of in-furnace introduction gases so that the in-furnace introduction gas flow rate ratio can be changed. And a gas introduction amount control means that selectively controls only one of them at the same time. 前記表面硬化処理を前記ガス軟窒化処理とし、
前記処理炉と前記水素濃度検出手段とを連通する水素濃度検出配管と、
前記水素濃度検出配管の温度を制御する配管温度制御手段と、を備え、
前記配管温度制御手段は、前記水素濃度検出配管内で前記炉内ガスが固体として析出しないように、前記アンモニアガスに応じて前記水素濃度検出配管の温度を６０〜１００℃の範囲内に制御することを特徴とする請求項２に記載した表面硬化処理装置。 The surface hardening treatment is the gas soft nitriding treatment,
A hydrogen concentration detection pipe communicating the processing furnace and the hydrogen concentration detection means;
A pipe temperature control means for controlling the temperature of the hydrogen concentration detection pipe,
The pipe temperature control means controls the temperature of the hydrogen concentration detection pipe within a range of 60 to 100 ° C. according to the ammonia gas so that the furnace gas does not precipitate as a solid in the hydrogen concentration detection pipe. The surface hardening processing apparatus according to claim 2. 前記処理炉と前記水素濃度検出手段との間に介装し、前記処理炉と前記水素濃度検出手段とを連通させる連通状態と、前記処理炉と前記水素濃度検出手段との間を閉鎖する閉鎖状態と、を切換可能な開閉弁と、
前記ガス導入量制御手段の動作状態に応じて前記開閉弁を前記連通状態または前記閉鎖状態に切り換える開閉弁切換え制御手段と、を備えることを特徴とする請求項１から請求項３のうちいずれか１項に記載した表面硬化処理装置。 A communication state interposed between the processing furnace and the hydrogen concentration detection means, and a communication state in which the processing furnace and the hydrogen concentration detection means communicate with each other, and a closure for closing between the processing furnace and the hydrogen concentration detection means An on-off valve capable of switching between the state,
4. An on-off valve switching control means for switching the on-off valve to the communication state or the closed state in accordance with an operating state of the gas introduction amount control means. The surface hardening processing apparatus as described in 1 item | term.
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