JPH04107256A - Carburizing furnace - Google Patents
Carburizing furnaceInfo
- Publication number
- JPH04107256A JPH04107256A JP2225545A JP22554590A JPH04107256A JP H04107256 A JPH04107256 A JP H04107256A JP 2225545 A JP2225545 A JP 2225545A JP 22554590 A JP22554590 A JP 22554590A JP H04107256 A JPH04107256 A JP H04107256A
- Authority
- JP
- Japan
- Prior art keywords
- carburizing
- gas
- carburizing gas
- heating chamber
- heating furnace
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000005255 carburizing Methods 0.000 title claims abstract description 140
- 238000010438 heat treatment Methods 0.000 claims abstract description 94
- 239000000463 material Substances 0.000 claims description 51
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 abstract description 62
- 239000004071 soot Substances 0.000 abstract description 16
- 239000007789 gas Substances 0.000 description 93
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 24
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 16
- 229910001873 dinitrogen Inorganic materials 0.000 description 16
- 239000001294 propane Substances 0.000 description 12
- 238000010791 quenching Methods 0.000 description 11
- 230000000171 quenching effect Effects 0.000 description 11
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 10
- 229910052799 carbon Inorganic materials 0.000 description 10
- 238000005979 thermal decomposition reaction Methods 0.000 description 10
- 238000000034 method Methods 0.000 description 9
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 8
- 238000010586 diagram Methods 0.000 description 7
- 238000009792 diffusion process Methods 0.000 description 6
- 239000001273 butane Substances 0.000 description 5
- 230000007423 decrease Effects 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- IJDNQMDRQITEOD-UHFFFAOYSA-N n-butane Chemical compound CCCC IJDNQMDRQITEOD-UHFFFAOYSA-N 0.000 description 5
- OFBQJSOFQDEBGM-UHFFFAOYSA-N n-pentane Natural products CCCCC OFBQJSOFQDEBGM-UHFFFAOYSA-N 0.000 description 5
- 229910052742 iron Inorganic materials 0.000 description 4
- 239000003054 catalyst Substances 0.000 description 3
- 238000011156 evaluation Methods 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 238000010186 staining Methods 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 238000000354 decomposition reaction Methods 0.000 description 2
- 238000010790 dilution Methods 0.000 description 2
- 239000012895 dilution Substances 0.000 description 2
- 229930195733 hydrocarbon Natural products 0.000 description 2
- 150000002430 hydrocarbons Chemical class 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 239000012528 membrane Substances 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 230000032258 transport Effects 0.000 description 2
- YYAVXASAKUOZJJ-UHFFFAOYSA-N 4-(4-butylcyclohexyl)benzonitrile Chemical compound C1CC(CCCC)CCC1C1=CC=C(C#N)C=C1 YYAVXASAKUOZJJ-UHFFFAOYSA-N 0.000 description 1
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- QSJXEFYPDANLFS-UHFFFAOYSA-N Diacetyl Chemical compound CC(=O)C(C)=O QSJXEFYPDANLFS-UHFFFAOYSA-N 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 238000005256 carbonitriding Methods 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- -1 for example Substances 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000003345 natural gas Substances 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- FAIAAWCVCHQXDN-UHFFFAOYSA-N phosphorus trichloride Chemical compound ClP(Cl)Cl FAIAAWCVCHQXDN-UHFFFAOYSA-N 0.000 description 1
- 201000003034 pontocerebellar hypoplasia type 4 Diseases 0.000 description 1
- 230000001568 sexual effect Effects 0.000 description 1
- 238000002791 soaking Methods 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/10—Reduction of greenhouse gas [GHG] emissions
- Y02P10/143—Reduction of greenhouse gas [GHG] emissions of methane [CH4]
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は浸炭炉に係り、特に、浸炭炉内での煤の発生及
び被浸炭材表面への煤の付着を防止可能な真空浸炭炉に
関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a carburizing furnace, and more particularly to a vacuum carburizing furnace that can prevent the generation of soot in the carburizing furnace and the adhesion of soot to the surface of the carburized material. .
従来、被浸炭材を真空浸炭する方法として、Ｈｅａｔ
Ｔｒｅａｔｍｅｎｔ ｏｆ ＭｅｔａｌＳ；ヒー
ト トリートメント オブ メタルズ、１９８９年４月
発行のｐ９３〜９４に記載されているパルス法のように
、加熱炉内の気圧を任意に設定し、当該加熱炉内が設定
した気圧になるまで浸炭性ガスを当該加熱炉内に供給し
、該加熱炉内が設定気圧に達した後は、当該浸炭性ガス
を排気し、前記加熱炉内が設定気圧まで下がった後は、
該浸炭性ガスの排気を中止し、再び当該加熱炉内が設定
した気圧になるまで浸炭性ガスを当該加熱炉内に供給す
るというサイクルを連続的に繰り返す方法が存在する。Conventionally, as a method for vacuum carburizing carburized materials, Heat
Treatment of Metals: As in the pulse method described in Heat Treatment of Metals, April 1989 issue, pages 93-94, the air pressure inside the heating furnace is arbitrarily set, and the air pressure inside the heating furnace reaches the set air pressure. After the carburizing gas is supplied into the heating furnace until the pressure inside the heating furnace reaches the set pressure, the carburizing gas is exhausted, and after the pressure inside the heating furnace drops to the set pressure,
There is a method of continuously repeating a cycle of stopping the exhaust of the carburizing gas and supplying the carburizing gas into the heating furnace until the inside of the heating furnace reaches a set pressure again.
この従来例では、加熱炉内の気圧と浸炭性ガス流量を管
理することで、真空浸炭炉内での煤の発生及び被浸炭材
表面への煤の付着を防止することができる。In this conventional example, the generation of soot in the vacuum carburizing furnace and the adhesion of soot to the surface of the carburized material can be prevented by controlling the air pressure and carburizing gas flow rate in the heating furnace.
前記従来例は、直接加熱炉内に浸炭性ガス、例えば、主
としてメタンを８０〜８５％含有している天然ガス又は
プロパン等を供給して浸炭を行っている。前記浸炭性ガ
スは、前記加熱炉内で熱分解するが、この熱分解反応は
最も安定なメタンの熱分解
ＣＨ，→２Ｈｚ＋Ｃｓ ・・−・−（１）により律
速される。In the conventional example, carburizing is performed by directly supplying a carburizing gas, for example, natural gas or propane containing 80 to 85% methane, directly into the heating furnace. The carburizing gas is thermally decomposed in the heating furnace, and this thermal decomposition reaction is rate-determined by the most stable thermal decomposition of methane CH,→2Hz+Cs (1).
ここで、被浸炭材が装入されていない真空浸炭炉を基準
にすると、前記（１）式の熱分解の進行は温度及び時間
により決定する。即ち、温度が高い程熱分解の進行が速
く、時間が長い程熱分解率は高くなる。さらにここで、
浸炭温度を一定にすると、前記（１）式の熱分解の進行
は時間のみに律速される。Here, based on a vacuum carburizing furnace in which no material to be carburized is charged, the progress of thermal decomposition in equation (1) is determined by temperature and time. That is, the higher the temperature, the faster the thermal decomposition progresses, and the longer the time, the higher the thermal decomposition rate. Further here,
When the carburizing temperature is kept constant, the progress of the thermal decomposition in equation (1) is rate-limited only by time.
これより、真空浸炭における浸炭性を決定するパラメー
タは、浸炭性ガスの加熱炉内滞留時間であることがわか
る。From this, it can be seen that the parameter that determines the carburizing property in vacuum carburizing is the residence time of the carburizing gas in the heating furnace.
いま、加熱炉内容積をｖＢ）、加熱炉内で熱膨張、熱分
解した後の出側ガス流量をＦ Ｃ１／Ｓ）、加熱炉内気
圧をＰ（Ｔｏｒｒ）とすると、浸炭性ガスの平均加熱炉
内滞留時間（１）は、Ｔ−＝ （Ｖ／Ｆ）Ｘ （Ｐ／７
６０） （ｓｅｃ）−−−一〜−（２）
で表される。Now, if the heating furnace internal volume is vB), the outlet gas flow rate after thermal expansion and thermal decomposition in the heating furnace is F C1/S), and the heating furnace internal pressure is P (Torr), then the average carburizing gas is The residence time in the heating furnace (1) is T-= (V/F)X (P/7
60) (sec)---1~-(2) Represented by:
前記（２）式において、出側ガス流量Ｆと加熱炉内気圧
Ｐとを固定すると、加熱炉内容積■は一定であることか
ら、真空浸炭における浸炭性を決定するパラメータであ
る前記（２）式の平均加熱炉内滞留時間（１）が定まる
ことがわかる。即ち、ガス流量Ｆと加熱炉内気圧Ｐを管
理することで、真空浸炭における浸炭性を決定すること
ができる。In the above equation (2), when the outlet gas flow rate F and the heating furnace internal pressure P are fixed, the heating furnace internal volume ■ is constant, so the above (2) is a parameter that determines the carburizability in vacuum carburizing. It can be seen that the average residence time in the heating furnace (1) of the equation is determined. That is, by controlling the gas flow rate F and the heating furnace internal pressure P, the carburizability in vacuum carburizing can be determined.
しかしながら、加熱炉内に被浸炭材、例えば、鉄を装入
した場合、当該鉄表面はメタンが熱分解する際に触媒と
して働くため、鉄の装入量によりメタンの熱分解の進行
が変動する。このため、当該熱分解の進行を、前記のよ
うに温度及び時間により決定することは極めて困難であ
り、ガス流量Ｆと加熱炉内気圧Ｐを管理することで、真
空浸炭における浸炭性を決定することはできないという
課題があった。However, when a carburized material such as iron is charged into a heating furnace, the surface of the iron acts as a catalyst when methane is thermally decomposed, so the progress of methane thermal decomposition varies depending on the amount of iron charged. . For this reason, it is extremely difficult to determine the progress of the thermal decomposition based on temperature and time as described above, and the carburizability in vacuum carburization is determined by controlling the gas flow rate F and the pressure inside the heating furnace P. The problem was that it could not be done.
一方、被浸炭材の装入量が一定の場合でも、鉄の表面炭
素濃度が固溶限に達すると触媒としての働きが低下する
ため、やはりメタンの熱分解の進行が変動し、前記と同
様、ガス流量Ｆと加熱炉内気圧Ｐを管理することで、真
空浸炭における浸炭性を決定することはできないという
課題があった。On the other hand, even when the charging amount of carburized material is constant, when the surface carbon concentration of iron reaches the solid solubility limit, its function as a catalyst decreases, so the progress of thermal decomposition of methane fluctuates, and the same as above occurs. However, there was a problem in that the carburizability in vacuum carburizing could not be determined by controlling the gas flow rate F and the heating furnace internal pressure P.
そして、前記従来例は、被浸炭材の装入量の増減に伴い
炭素を吸収する被浸炭材の表面積が増減し、被浸炭材表
面への炭素流入量が変化する、或いは、浸炭時に被浸炭
材の表面炭素濃度が固溶限に達すると、被浸炭材表面へ
の炭素流入速度は著しく低下しく石神等；日本金属学会
誌、第５０巻第９号、１９８６年発行、Ｐ８４５〜８５
１）、被浸炭材表面への炭素流入量が変化しても、これ
に対応して浸炭性ガスの供給量を調節していないため、
例えば、被浸炭材表面への炭素流入量が少なくなると、
加熱炉内に浸炭性ガスが過剰に供給され、余った浸炭性
ガスは多量の煤を発生し、被浸炭材を汚す、浸炭むらが
発生する原因となる等の課題が生じていた。In the conventional example, the surface area of the carburized material that absorbs carbon increases or decreases as the charging amount of the carburized material increases or decreases, and the amount of carbon flowing into the surface of the carburized material changes, or the amount of carburized material changes during carburizing. When the surface carbon concentration of the material reaches the solid solubility limit, the rate of carbon inflow to the surface of the carburized material decreases significantly. Ishigami et al.; Journal of the Japan Institute of Metals, Vol.
1) Even if the amount of carbon flowing into the surface of the carburized material changes, the amount of carburizing gas supplied is not adjusted accordingly.
For example, when the amount of carbon flowing into the surface of the carburized material decreases,
Excessive carburizing gas is supplied into the heating furnace, and the excess carburizing gas generates a large amount of soot, which causes problems such as staining the carburized material and causing uneven carburization.
さらに、前記（２）式において、加熱炉内容積■は一定
であるが、加熱炉内に存在している各成分ガスの分圧、
例えば、メタン分圧（ＰＣｌ３ ）とメタン・水素分圧
比（Ｐ ＣＨ４／ Ｐ ）Ｉｔ）は、浸炭状態により常
に変化しているにもかかわらず、これを考慮していない
ため、加熱炉内に浸炭性ガスが過剰に存在しているのか
不足しているのかを把握することができないという課題
もあった。Furthermore, in equation (2) above, the internal volume of the heating furnace (■) is constant, but the partial pressure of each component gas existing in the heating furnace,
For example, although the methane partial pressure (PCl3) and the methane/hydrogen partial pressure ratio (PCH4/P)It) constantly change depending on the carburizing state, this is not taken into consideration. Another problem was that it was not possible to determine whether sexual gases were present in excess or insufficient.
そこで、このような課題を解決するため本発明は、加熱
炉内の状況に応して浸炭性ガスの供給量を制御すること
で、常に被浸炭材に対して最適な量の浸炭性ガスを供給
し、浸炭炉内での煤の発生及び被浸炭材表面への煤の付
着を防止可能な浸炭炉を掃供することを目的とする。Therefore, in order to solve these problems, the present invention always supplies the optimum amount of carburizing gas to the material to be carburized by controlling the supply amount of carburizing gas according to the situation inside the heating furnace. The purpose is to supply and clean a carburizing furnace that can prevent the generation of soot in the furnace and the adhesion of soot to the surface of the carburized material.
この目的を達成するために本発明は、被浸炭材を加熱す
る加熱炉と、前記加熱炉に浸炭性ガスを供給する浸炭性
ガス供給管と、当該加熱炉を減圧排気する排気管と、を
有する浸炭炉において、前記被浸炭材の浸炭期に、当該
加熱炉内の浸炭性ガス濃度を計測する計測手段と、この
計測値に基づいて前記加熱炉内へ供給する浸炭性ガス供
給量を制御する制御手段、とを備えた浸炭炉であること
を特徴とするものである。In order to achieve this object, the present invention includes a heating furnace that heats a material to be carburized, a carburizing gas supply pipe that supplies carburizing gas to the heating furnace, and an exhaust pipe that decompresses and exhausts the heating furnace. In a carburizing furnace having a carburizing furnace, a measuring means for measuring the carburizing gas concentration in the heating furnace during the carburizing period of the carburized material, and controlling the amount of carburizing gas supplied into the heating furnace based on this measurement value. The carburizing furnace is characterized in that it is equipped with a control means for controlling the carburizing furnace.
二の発明に係わる浸炭炉によれば、被浸炭材の浸炭期に
、加熱炉内の浸炭性ガス濃度を直接計測することで、常
に正確に加熱炉内の浸炭性ガスの濃度を把握することが
できる。そして、前記浸炭性ガス濃度に応じて、加熱炉
内に供給する浸炭性ガスの供給量を制御することにより
、被浸炭材の装入量、被浸炭材表面への炭素流入速度の
変化にかかわらず、被浸炭材に対して常に最適な量の浸
炭性ガスを供給することができる。According to the carburizing furnace according to the second invention, the concentration of carburizing gas in the heating furnace can always be accurately grasped by directly measuring the concentration of carburizing gas in the heating furnace during the carburizing period of the carburized material. I can do it. By controlling the amount of carburizing gas supplied into the heating furnace according to the carburizing gas concentration, the amount of carburizing material to be charged and the speed of carbon flowing into the surface of the material to be carburized can be changed. First, an optimal amount of carburizing gas can always be supplied to the material to be carburized.
このため、加熱炉内に浸炭性ガスが過剰に供給されるこ
とがなく、煤の発生を防ぐことができる。Therefore, excessive carburizing gas is not supplied into the heating furnace, and soot generation can be prevented.
この結果、被浸炭材の表面に煤が付着し、被浸炭材を汚
す、或いは浸炭むらの発生を防ぐことができ、且つ、最
適な浸炭時間で所望の浸炭品を得ることができる。As a result, it is possible to prevent soot from adhering to the surface of the material to be carburized, staining the material to be carburized, or to prevent uneven carburization from occurring, and to obtain a desired carburized product with an optimal carburizing time.
次に本発明の実施例について、図面に基づいて説明する
。Next, embodiments of the present invention will be described based on the drawings.
第１図は、本発明に係る真空浸炭炉の構成図であり、第
２図は、第１図における■−■断面図、第３図は、加熱
炉内の浸炭性ガス濃度を直接計測する浸炭性ガス濃度分
析装置及び計測結果に応じて浸炭性ガスの供給量を制御
する調節計の構成図を示す。Fig. 1 is a configuration diagram of a vacuum carburizing furnace according to the present invention, Fig. 2 is a sectional view taken along the line ■-■ in Fig. 1, and Fig. 3 is a diagram showing a method for directly measuring the carburizing gas concentration in the heating furnace. The block diagram of a carburizing gas concentration analyzer and a controller that controls the supply amount of carburizing gas according to the measurement results is shown.
第１図に示されるように、本発明における真空浸炭炉は
、加熱室２を有する真空加熱炉１と焼入油が入っている
焼入槽３を有するベスチプル４とを中間扉５を介して連
設し、さらに、浸炭性ガス・窒素ガス供給管９より浸炭
性ガス及び窒素ガスが加熱室２に供給される。そして、
この加熱室２には、サンプルガス吸引口２２を介して浸
炭性ガス濃度分析装置７０と調節計３３とが連設する構
造からなる。As shown in FIG. 1, the vacuum carburizing furnace of the present invention connects a vacuum heating furnace 1 having a heating chamber 2 and a bestiple 4 having a quenching tank 3 containing quenching oil through an intermediate door 5. Further, carburizing gas and nitrogen gas are supplied to the heating chamber 2 from a carburizing gas/nitrogen gas supply pipe 9 which is connected to the heating chamber 2 . and,
This heating chamber 2 has a structure in which a carburizing gas concentration analyzer 70 and a controller 33 are connected via a sample gas suction port 22.
前記ベスチブル４内は、ベスチプル４と加熱室２との間
で、被浸炭材Ｗを搬送する処理材搬送装置１３と浸炭後
の被浸炭材Ｗを冷却する冷却用ファン１４及び焼入のた
めに被浸炭材Ｗを昇降する焼入エレベータ１５Ａから構
成されている。尚、１６は装入抽出扉である。Inside the bestible 4, between the bestible 4 and the heating chamber 2, there are a processing material conveying device 13 that transports the carburized material W, a cooling fan 14 that cools the carburized material W after carburizing, and a cooling fan 14 for quenching. It consists of a quenching elevator 15A that raises and lowers the carburized material W. In addition, 16 is a charging/extracting door.
一方、第２図に示されるように、前記加熱室２は炉殻１
１内に空間部１２を介して設けられている。加熱室２内
には、ヒータ６と循環ファン７及び上下可動炉床８が設
けられている。上下可動炉床８の下部には、上下可動炉
床８の上下運動を制御する上下可動炉床エレベータ１５
Ｂが設けられている。浸炭性ガス・窒素ガス供給管９及
び真空排気管１０はそれぞれ前記加熱室２内に連通され
ており、真空排気装置４２が真空排気管１０を介して加
熱室２内に連通している。この真空排気装置４２はロー
クリポンプ４９、圧力制御弁４０、フィルタ４１から構
成されている。On the other hand, as shown in FIG.
1 with a space 12 in between. Inside the heating chamber 2, a heater 6, a circulation fan 7, and a vertically movable hearth 8 are provided. At the lower part of the vertically movable hearth 8, there is a vertically movable hearth elevator 15 that controls the vertical movement of the vertically movable hearth 8.
B is provided. The carburizing gas/nitrogen gas supply pipe 9 and the evacuation pipe 10 are each communicated with the heating chamber 2, and the evacuation device 42 is communicated with the heating chamber 2 via the evacuation pipe 10. This evacuation device 42 is composed of a low-pressure pump 49, a pressure control valve 40, and a filter 41.
また、第３図に示されるように、サンプルガス吸引口２
２には電磁弁２３を介してダイヤフラム型ドライ真空ポ
ンプ２４が連設している。この真空ポンプ２４は２つに
分岐してサンプルガス排気管５１Ａ及び５１Ｂに連通し
ており、サンプルガス排気管５１Ａにはガスクーラ２５
が連通され、サンプルガス排気管５１Ｂには分岐弁３１
が設けられている。一方、ガスクーラ２５は２つに分岐
してドレン２６及び流量調節弁２７に連設しており、流
量調節弁２７は流量計２８及びメンプレンフルタ２９を
介して赤外線メタン分析計３０に連設している。このメ
タン分析計３０にはサンプルガス排気管５１Ｃが連通し
ており、連結部３２でサンプルガス排気管５１Ｂと連結
し、その終端はサンプルガス出口６０に続いている。ま
た、メタン分析計３０は調節計３３に連設しており、メ
タン分析計３０で分析した値（信号）を調節計３３に伝
達する。そして、調節計３３は電磁弁１８に連設してい
る。In addition, as shown in FIG. 3, the sample gas suction port 2
2 is connected to a diaphragm type dry vacuum pump 24 via a solenoid valve 23. This vacuum pump 24 is branched into two and communicates with sample gas exhaust pipes 51A and 51B, and a gas cooler 25 is connected to the sample gas exhaust pipe 51A.
is connected to the sample gas exhaust pipe 51B, and a branch valve 31 is connected to the sample gas exhaust pipe 51B.
is provided. On the other hand, the gas cooler 25 is branched into two parts and connected to a drain 26 and a flow control valve 27, and the flow control valve 27 is connected to an infrared methane analyzer 30 via a flow meter 28 and a membrane filter 29. ing. A sample gas exhaust pipe 51C communicates with this methane analyzer 30, and is connected to a sample gas exhaust pipe 51B at a connecting portion 32, and its terminal end continues to a sample gas outlet 60. Further, the methane analyzer 30 is connected to the controller 33 and transmits the value (signal) analyzed by the methane analyzer 30 to the controller 33. The controller 33 is connected to the solenoid valve 18.
次に、浸炭性ガス濃度分析装置７０及び調節計３３の動
作について説明する。Next, the operations of the carburizing gas concentration analyzer 70 and the controller 33 will be explained.
加熱室２に被浸炭材Ｗを装入し浸炭する際、被浸炭材Ｗ
の浸炭期に、加熱室２内の気圧が予め設定しておいた設
定値を越えると電磁弁２３が開き、真空ポンプ２４によ
り加熱室２内の浸炭性ガスが吸引される。前記ａｍ弁２
３は所定時間の浸炭期が完了すると閉じるように設定し
である。吸引された浸炭性ガスはガスクーラ２５で下部
され、流量調節弁２７．流量計２８により所定の流量に
調節され、次いで、メンブレンフィルタ２９を通過して
赤外線メタン分析計３０に送られる。このメタン分析計
３０により、浸炭性ガス濃度を計測する。この濃度値が
調節計３３に送られ、予め設定された浸炭性ガス濃度と
浸炭性ガス供給量との関係についての記憶テーブルに基
づいて、電磁弁１８に０Ｎ１０ＦＦの信号を送り、電磁
弁１８を閉関し、加熱室２内に供給する浸炭性ガス供給
量を調整する。この結果、加熱室２内の浸炭性ガス濃度
を常に一定に保つことができる。即ち、前記濃度値が予
め設定した濃度を越えると、電磁弁１８にＯＦＦ信号が
送られ電磁弁１８は閉じ、加熱室２に浸炭性ガスが供給
されなくなる。尚、濃度の計測が終了した浸炭性ガスは
、サンプルガス排気管５１Ｃを通過し、サンプルガス出
口６０より廃棄される。また、浸炭期が完了し電磁弁２
３が閉じた後は、分岐弁３１を開は不必要な浸炭性ガス
を廃棄する。When charging the carburized material W into the heating chamber 2 and carburizing it, the carburized material W
During the carburizing period, when the air pressure in the heating chamber 2 exceeds a preset value, the solenoid valve 23 opens and the carburizing gas in the heating chamber 2 is sucked by the vacuum pump 24. Said am valve 2
3 is set to close when the carburizing period of a predetermined time is completed. The sucked carburizing gas is lowered by a gas cooler 25 and then passed through a flow rate control valve 27. The flow rate is adjusted to a predetermined level by a flow meter 28 , and then passed through a membrane filter 29 and sent to an infrared methane analyzer 30 . This methane analyzer 30 measures the carburizing gas concentration. This concentration value is sent to the controller 33, which sends a signal of 0N10FF to the solenoid valve 18 based on a preset memory table regarding the relationship between the carburizing gas concentration and the carburizing gas supply amount. The amount of carburizing gas supplied into the heating chamber 2 is adjusted. As a result, the carburizing gas concentration within the heating chamber 2 can always be kept constant. That is, when the concentration value exceeds a preset concentration, an OFF signal is sent to the solenoid valve 18, the solenoid valve 18 closes, and the carburizing gas is no longer supplied to the heating chamber 2. The carburizing gas whose concentration has been measured passes through the sample gas exhaust pipe 51C and is discarded from the sample gas outlet 60. In addition, the carburizing period is completed and solenoid valve 2
3 is closed, the branch valve 31 is opened to discard unnecessary carburizing gas.
本発明で用いる浸炭性ガスとしては、メタン。The carburizing gas used in the present invention is methane.
プロパン、ブタン等の炭化水素ガス、或いはＣ０が好適
である。メタンは、前記（１）式のように加熱室内で熱
分解する。プロパン、ブタンは、それぞれ加熱室内で
Ｃｓ Ｈｓ→ＣＨａ ＋２ Ｈｚ ＋ ２ ＣｓＣ，Ｈ
，、→ＣＨａ ＋ ３ Ｈｚ ＋ ３ Ｃｓのように熱
分解し、さらに両者共
ＣＨ，→２Ｈｚ ＋Ｃｓ
のように熱分解する。そして、炭化水素の分解は、メタ
ンの分解反応に律速される。これより、浸炭性ガスとし
てメタン、プロパン及びブタンを用いる場合は、加熱室
内のメタン濃度を計測することが、浸炭性ガス供給量を
制御する上で望ましい。Hydrocarbon gases such as propane and butane, or CO are suitable. Methane is thermally decomposed in the heating chamber as shown in equation (1) above. Propane and butane are each converted into Cs Hs → CHa +2 Hz + 2 CsC,H in the heating chamber.
, , → CHa + 3 Hz + 3 Cs, and both are CH, → 2 Hz + Cs. The rate of decomposition of hydrocarbons is determined by the decomposition reaction of methane. Therefore, when using methane, propane, or butane as the carburizing gas, it is desirable to measure the methane concentration in the heating chamber in order to control the amount of carburizing gas supplied.
また、プロパン、ブタンは、Ｎｉ触媒を用いて、１００
０〜１１００°Ｃに加熱すると、２ Ｃ３Ｈ８＋３０ｈ
＋ １１．２８ Ｎｚ ＝６ ＣＯ＋８ Ｈｚ ＋
１１．２８ Ｎｚ
Ｃ，Ｈ，。＋２０□＋７．５２ Ｎｚ ＝ ４ ＣＯ＋
５ Ｈｚ＋ ７．５２ Ｎ ｔ
のように変成される。これより、浸炭性ガスとしてプロ
パン及びブタンを用い、変成して使用する場合は、加熱
室内のｃｏ濃度を計測することで、浸炭性ガス供給量を
制御することが可能である。In addition, propane and butane can be prepared at 100% by using a Ni catalyst.
When heated from 0 to 1100°C, 2C3H8+30h
+ 11.28 Nz = 6 CO + 8 Hz +
11.28 Nz C,H,. +20□+7.52 Nz = 4 CO+
5 Hz+ 7.52 N t . Therefore, when propane and butane are used as the carburizing gas and used after being modified, it is possible to control the amount of carburizing gas supplied by measuring the co concentration in the heating chamber.
そして、浸炭性ガスとして、ｃｏ２を用いる場合は、加
熱室内のｃｏ２１度を計測することで、浸炭性ガス供給
量を制御することが可能である。When CO2 is used as the carburizing gas, the amount of carburizing gas supplied can be controlled by measuring the CO21 degree in the heating chamber.
次に、本発明の具体的な実施例を説明する。Next, specific examples of the present invention will be described.
被浸炭材Ｗの浸炭を第１表に示す浸炭条件で行った。こ
れを、各工程毎に説明する。尚、第４図は、浸炭サイク
ル及びメタン濃度の制御図である。The carburized material W was carburized under the carburizing conditions shown in Table 1. This will be explained for each step. Incidentally, FIG. 4 is a control diagram of the carburizing cycle and methane concentration.
（以下、余白）
第 １ 表
（昇温・均熱工程）
加熱室２内に被浸炭材Ｗを装入する。次いで、加熱室２
内圧力を真空排気装置２２にて、大気圧（７６０Ｔｏｒ
ｒ）から５Ｔｏ ｒ ｒ以下に減圧する。その後、９３
０°Ｃまで被浸炭材Ｗを昇温し、被浸炭材Ｗの表面と芯
部及び各部位が均一になるよう、所定時間保持する。こ
の時、循環ファン７により熱伝導を高め、均熱化を促進
するため、窒素ガスを供給してもよい、尚、窒素ガスを
供給した際の加熱室２内圧力は、第４図に示す破線のよ
うに変化する。(Hereinafter, blank space) Table 1 (Temperature raising/soaking process) The carburized material W is charged into the heating chamber 2. Next, heating chamber 2
The internal pressure is reduced to atmospheric pressure (760 Torr) using the vacuum evacuation device 22.
Reduce the pressure from r) to 5 Torr or less. After that, 93
The temperature of the carburized material W is raised to 0° C. and held for a predetermined time so that the surface, core, and other parts of the carburized material W are uniform. At this time, nitrogen gas may be supplied using the circulation fan 7 to increase heat conduction and promote heat uniformity.The pressure inside the heating chamber 2 when nitrogen gas is supplied is shown in Fig. 4. It changes as shown by the dashed line.
（浸炭工程）
電磁弁１７及び１８を開いて、プロパン、及び窒素ガス
を減圧された加熱室２に浸炭性ガス・窒素ガス供給管９
を通じて供給する。この時、プロパンの供給量は電磁弁
１８を開閉することにより調節する。また、窒素ガスの
供給量は電磁弁１７を開閉することにより調節する。そ
して、圧力制御弁４０を調節し加熱室２内の圧力を６５
０Ｔ。(Carburizing process) Open the solenoid valves 17 and 18 and supply the carburizing gas/nitrogen gas supply pipe 9 to the heating chamber 2 which has a reduced pressure of propane and nitrogen gas.
Supply through. At this time, the amount of propane supplied is adjusted by opening and closing the solenoid valve 18. Further, the amount of nitrogen gas supplied is adjusted by opening and closing the solenoid valve 17. Then, the pressure control valve 40 is adjusted to reduce the pressure inside the heating chamber 2 to 65%.
0T.
ｒｒに調節し、加熱室２で被浸炭材Ｗを所定時間浸炭す
る。浸炭期のメタン濃度の計測は、加熱室２内の圧力が
６００Ｔｏｒｒに達すると開始するように設定した。即
ち、加熱室２内の圧力が、６００Ｔｏ ｒ ｒを越える
と、加熱室２内のメタンがサンプルガス吸引口２２より
浸炭性ガス分析装置に導入され、メタンガスが赤外線メ
タン分析計３０に到達する。ここで、メタン濃度を計測
し、その値により電磁弁１８を開閉して加熱室２に供給
するプロパンの供給量を制御する。このようにして、加
熱室２内の浸炭性ガス濃度（メタン濃度）は、第４図に
示すように一定に保たれる。rr, and the carburized material W is carburized in the heating chamber 2 for a predetermined period of time. Measurement of the methane concentration during the carburizing period was set to start when the pressure inside the heating chamber 2 reached 600 Torr. That is, when the pressure in the heating chamber 2 exceeds 600 Torr, methane in the heating chamber 2 is introduced into the carburizing gas analyzer through the sample gas suction port 22, and the methane gas reaches the infrared methane analyzer 30. Here, the methane concentration is measured, and the amount of propane supplied to the heating chamber 2 is controlled by opening and closing the electromagnetic valve 18 based on the measured value. In this way, the carburizing gas concentration (methane concentration) in the heating chamber 2 is kept constant as shown in FIG.
尚、浸炭期に窒素ガスを供給すると浸炭性ガスの拡散を
促進し、好ましい浸炭状態が得られるが、必ずしも窒素
ガスを供給しなくても良い。Note that, if nitrogen gas is supplied during the carburizing period, diffusion of the carburizing gas is promoted and a preferable carburized state is obtained, but it is not necessary to supply nitrogen gas.
（拡散工程）
電磁弁１７及び１８を閉じ、プロパン及び窒素ガスを加
熱室２へ供給することを停止する。その後、真空排気装
置Ｉ４２により加熱室２内の圧力を６５０Ｔｏｒｒから
５Ｔｏ ｒ ｒ以下に減圧する。(Diffusion step) The solenoid valves 17 and 18 are closed, and the supply of propane and nitrogen gas to the heating chamber 2 is stopped. Thereafter, the pressure inside the heating chamber 2 is reduced from 650 Torr to 5 Torr or less using the evacuation device I42.
この工程により被浸炭材Ｗに浸炭した炭素を芯部に向け
て拡散させる。Through this process, the carbon carburized into the carburized material W is diffused toward the core.
（焼入工程）
浸炭及び拡散工程を終了した被浸炭材Ｗを油中焼入硬化
するため、バルブ１７を開き、加熱室２に窒素ガスを供
給して６５０Ｔｏｒｒに昇圧し、同時にベスチブル４に
も窒素ガスを供給し、加熱室２とベスチブル４との内部
圧力を無酸化、等圧状態とする。その後、中間扉５を開
け、処理材運搬装置１３により被浸炭材Ｗをベスチブル
４に移動し、次いで、中間扉５を閉じ、焼入エレベータ
１５Ａを用いてを焼入層３にある焼入油中にて焼入を行
う。次いで、焼入エレベータ１５を上昇させ、搬入抽出
扉１６を開き被浸炭材Ｗを取り出す。(Quenching process) In order to harden the carburized material W that has completed the carburizing and diffusion process by quenching in oil, the valve 17 is opened and nitrogen gas is supplied to the heating chamber 2 to increase the pressure to 650 Torr. Nitrogen gas is supplied to bring the internal pressures of the heating chamber 2 and bestible 4 into a non-oxidizing and equal pressure state. Thereafter, the intermediate door 5 is opened, the carburized material W is moved to the bestible 4 by the treated material transport device 13, the intermediate door 5 is closed, and the quenching oil in the quenching layer 3 is removed using the quenching elevator 15A. Quenching is performed inside. Next, the quenching elevator 15 is raised, the carry-in extraction door 16 is opened, and the carburized material W is taken out.
尚、第４図のＰｌは、加熱室２内を圧力制御することに
より浸炭性ガス流量を管理する従来例における設定圧力
を示している。Note that Pl in FIG. 4 indicates a set pressure in a conventional example in which the carburizing gas flow rate is managed by controlling the pressure inside the heating chamber 2.
このようにして得た被浸炭品（発明品）の評価を第２表
に示す。Table 2 shows the evaluation of the carburized product (invention product) thus obtained.
次に、比較例として、浸炭期のプロパンの供給を制御せ
ず固定し、その他の浸炭条件は前記実施例と同様にして
浸炭を行った。このようにして得た被浸炭品（比較品）
の評価を第２表に示す。Next, as a comparative example, carburization was carried out under the same conditions as in the previous example, except that the supply of propane during the carburizing period was not controlled and was fixed. Carburized product obtained in this way (comparison product)
The evaluation is shown in Table 2.
（以下、余白）
第２表
尚、評価方法は、
○ 良好（煤の発生、又は付着がかなり減少）Ｘ 不良
（煤の発生、又は付着がかなり多い）として行った。(Hereinafter, blank space) Table 2 The evaluation method was as follows: ○ Good (soot generation or adhesion is considerably reduced) X Poor (soot generation or adhesion is considerably large).
以上の結果から、浸炭期の加熱炉内のメタン濃度を計測
し、その値により加熱炉内へ供給する浸炭性ガス供給量
を制御し、常に被浸炭材に対して最適な供給を行うこと
で、浸炭炉内の煤の発生を激減することができ、被浸炭
材への煤の付着、汚れ、浸炭むらのない良好な被浸炭品
を得ることができた。From the above results, it is possible to measure the methane concentration in the heating furnace during the carburizing period, control the amount of carburizing gas supplied to the heating furnace based on that value, and always provide the optimal supply to the material to be carburized. It was possible to drastically reduce the generation of soot in the carburizing furnace, and to obtain a good carburized product with no soot adhesion to the carburized material, no stains, and no uneven carburization.
尚、本実施例では、真空浸炭炉について説明したが、連
続炉等、他の浸炭炉についても同様の効果が得られる。In this embodiment, a vacuum carburizing furnace has been described, but similar effects can be obtained with other carburizing furnaces such as a continuous furnace.
そして、本実施例では、浸炭の場合について説明したが
、浸炭性ガスに例えばアンモニアを混入して浸炭窒化を
行う場合でも同様の効果を得ることができる。In this embodiment, the case of carburizing has been described, but the same effect can be obtained even when carbonitriding is performed by mixing ammonia into the carburizing gas.
また、浸炭性ガスとしてプロパンを使用したが、これに
限らず、メタン、ブタン２ ＣＯ等、浸炭効果を有する
ガスであれば良い。そして、浸炭期の加熱炉内の浸炭性
ガス濃度の設定値は、使用する浸炭性ガスの種類、浸炭
温度、窒素ガスの希釈率等により任意に設定することが
でき、浸炭温度。Further, although propane is used as the carburizing gas, the present invention is not limited to this, and any gas having a carburizing effect may be used, such as methane, butane 2 CO, etc. The set value of the carburizing gas concentration in the heating furnace during the carburizing period can be arbitrarily set depending on the type of carburizing gas used, the carburizing temperature, the dilution rate of nitrogen gas, etc.
窒素ガスの希釈率等も浸炭及び拡散を行う程度により任
意に決めて良い。The dilution rate of nitrogen gas and the like may be arbitrarily determined depending on the degree of carburization and diffusion.
本実施例では、浸炭工程において、加熱室の圧力を６５
０Ｔｏｒｒ、浸炭温度を９３０°Ｃ１拡散時の温度を９
３０ ’Ｃとしたが、浸炭及び拡散を行う程度により、
変更しても良い。In this example, in the carburizing process, the pressure in the heating chamber was set to 65
0 Torr, carburizing temperature 930°C1 temperature during diffusion 9
30'C, but depending on the degree of carburizing and diffusion,
You may change it.
また、被浸炭材としては、５ＣＲ４２０Ｈの他公知の肌
焼鋼を適用できることは勿論である。Further, as the carburized material, it is of course possible to use other known case hardening steels besides 5CR420H.
以上説明したように本発明に係る浸炭炉によれば、被浸
炭材の浸炭期に、加熱炉内の浸炭性ガス濃度を直接計測
し、この計測値に基づいて加熱炉内に供給する浸炭性ガ
スの供給量を制御することにより、被浸炭材の装入量、
被浸炭材表面への炭素流入速度の変化にかかわらず、被
浸炭材に対して常に最適な量の浸炭性ガスを供給するこ
とができる。As explained above, according to the carburizing furnace according to the present invention, the carburizing gas concentration in the heating furnace is directly measured during the carburizing period of the carburized material, and the carburizing gas concentration is supplied to the heating furnace based on this measured value. By controlling the gas supply amount, the charging amount of carburized material,
Regardless of changes in the rate of carbon inflow to the surface of the material to be carburized, an optimum amount of carburizing gas can always be supplied to the material to be carburized.
このため、加熱炉内に浸炭性ガスが過剰に供給されるこ
とがないため、浸炭炉内に煤が発生することを防ぐこと
ができる。この結果、煤による被浸炭材の汚れ、或いは
浸炭むらのない高品質な浸炭品を得ることができる。Therefore, the carburizing gas is not excessively supplied into the heating furnace, so it is possible to prevent soot from being generated within the carburizing furnace. As a result, a high-quality carburized product can be obtained without staining the carburized material with soot or with no uneven carburization.
第１図は、本発明に係る真空浸炭炉の構成図、第２図は
、第１図における■−■断面図、第３図は、浸炭性ガス
濃度分析装置及び調節計の構成図、第４図は、浸炭サイ
クル及びメタン濃度の制御図を示す。
図中、１は真空加熱炉、２は加熱室、３は焼入層、４は
ベスチブル、９は浸炭性ガス・窒素ガス供給管、１８は
電磁弁、２２はサンプルガス吸引口、３０は赤外線メタ
ン分析計、３３は調節計、７０は浸炭性ガス濃度分析装
置を示す。FIG. 1 is a block diagram of a vacuum carburizing furnace according to the present invention, FIG. 2 is a sectional view taken along the line ■-■ in FIG. 1, and FIG. 3 is a block diagram of a carburizing gas concentration analyzer and a controller. Figure 4 shows a control diagram of the carburizing cycle and methane concentration. In the figure, 1 is a vacuum heating furnace, 2 is a heating chamber, 3 is a quenched layer, 4 is a bestible, 9 is a carburizing gas/nitrogen gas supply pipe, 18 is a solenoid valve, 22 is a sample gas suction port, and 30 is an infrared ray A methane analyzer, 33 a controller, and 70 a carburizing gas concentration analyzer.
Claims (1)
性ガスを供給する浸炭性ガス供給管と、当該加熱炉を減
圧排気する排気管と、を有する浸炭炉において、前記被
浸炭材の浸炭期に、当該加熱炉内の浸炭性ガス濃度を計
測する計測手段と、この計測値に基づいて前記加熱炉内
へ供給する浸炭性ガス供給量を制御する制御手段、とを
備えたことを特徴とする浸炭炉。(1) In a carburizing furnace, the carburizing furnace has a heating furnace that heats the carburized material, a carburizing gas supply pipe that supplies carburizing gas to the heating furnace, and an exhaust pipe that decompresses and exhausts the heating furnace. A measuring means for measuring the carburizing gas concentration in the heating furnace during the carburizing period of the material, and a control means for controlling the amount of carburizing gas supplied to the heating furnace based on this measured value. A carburizing furnace characterized by:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2225545A JPH04107256A (en) | 1990-08-28 | 1990-08-28 | Carburizing furnace |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2225545A JPH04107256A (en) | 1990-08-28 | 1990-08-28 | Carburizing furnace |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH04107256A true JPH04107256A (en) | 1992-04-08 |
Family
ID=16830973
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2225545A Pending JPH04107256A (en) | 1990-08-28 | 1990-08-28 | Carburizing furnace |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH04107256A (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0626467A1 (en) * | 1992-10-15 | 1994-11-30 | Kawasaki Steel Corporation | Method of continuously carburizing steel strip |
| JP2002107066A (en) * | 2000-09-28 | 2002-04-10 | Shinwa Jitsugyo Kk | Heat treatment furnace and method of operating the same |
| JP2004332075A (en) * | 2003-05-09 | 2004-11-25 | Toho Gas Co Ltd | Carburization control method and carburizing device using the method |
| JP2007113045A (en) * | 2005-10-19 | 2007-05-10 | Ishikawajima Harima Heavy Ind Co Ltd | Quality control method in vacuum carburizing and vacuum carburizing furnace |
| JP2010091239A (en) * | 2008-10-10 | 2010-04-22 | Osaka Gas Co Ltd | Furnace pressure control apparatus and furnace pressure control method |
| WO2011092998A1 (en) * | 2010-01-29 | 2011-08-04 | 国立大学法人熊本大学 | Method for treatment of metal surface, and surface-modified metal product |
| JP2017008403A (en) * | 2015-06-25 | 2017-01-12 | 学校法人トヨタ学園 | Carburizing control method |
-
1990
- 1990-08-28 JP JP2225545A patent/JPH04107256A/en active Pending
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0626467A1 (en) * | 1992-10-15 | 1994-11-30 | Kawasaki Steel Corporation | Method of continuously carburizing steel strip |
| EP0626467A4 (en) * | 1992-10-15 | 1995-03-01 | Kawasaki Steel Co | Method of continuously carburizing metal strip. |
| JP2002107066A (en) * | 2000-09-28 | 2002-04-10 | Shinwa Jitsugyo Kk | Heat treatment furnace and method of operating the same |
| JP2004332075A (en) * | 2003-05-09 | 2004-11-25 | Toho Gas Co Ltd | Carburization control method and carburizing device using the method |
| JP2007113045A (en) * | 2005-10-19 | 2007-05-10 | Ishikawajima Harima Heavy Ind Co Ltd | Quality control method in vacuum carburizing and vacuum carburizing furnace |
| JP2010091239A (en) * | 2008-10-10 | 2010-04-22 | Osaka Gas Co Ltd | Furnace pressure control apparatus and furnace pressure control method |
| WO2011092998A1 (en) * | 2010-01-29 | 2011-08-04 | 国立大学法人熊本大学 | Method for treatment of metal surface, and surface-modified metal product |
| JP5927646B2 (en) * | 2010-01-29 | 2016-06-01 | 国立大学法人 熊本大学 | Metal surface treatment |
| JP2017008403A (en) * | 2015-06-25 | 2017-01-12 | 学校法人トヨタ学園 | Carburizing control method |
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