JPH0470391B2 - - Google Patents
Info
- Publication number
- JPH0470391B2 JPH0470391B2 JP59040152A JP4015284A JPH0470391B2 JP H0470391 B2 JPH0470391 B2 JP H0470391B2 JP 59040152 A JP59040152 A JP 59040152A JP 4015284 A JP4015284 A JP 4015284A JP H0470391 B2 JPH0470391 B2 JP H0470391B2
- Authority
- JP
- Japan
- Prior art keywords
- furnace
- ammonia atmosphere
- steam
- supplied
- nitrocarburizing
- 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.)
- Expired - Lifetime
Links
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims description 32
- 229910021529 ammonia Inorganic materials 0.000 claims description 16
- 238000000034 method Methods 0.000 claims description 10
- 238000010438 heat treatment Methods 0.000 claims description 2
- 239000011148 porous material Substances 0.000 claims description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims 2
- 229910052742 iron Inorganic materials 0.000 claims 1
- 238000007789 sealing Methods 0.000 description 5
- 238000001816 cooling Methods 0.000 description 4
- 230000007547 defect Effects 0.000 description 4
- 238000005121 nitriding Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 150000004767 nitrides Chemical class 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 2
- 238000000354 decomposition reaction Methods 0.000 description 2
- 238000001000 micrograph Methods 0.000 description 2
- 238000006722 reduction reaction Methods 0.000 description 2
- 238000002485 combustion reaction Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000007791 dehumidification Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 238000003672 processing method Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Powder Metallurgy (AREA)
- Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
Description
【発明の詳細な説明】
本発明は焼結部品の軟窒化処理方法及びその装
置に関するもので、被処理品である焼結部品の体
積膨張による寸法不良品の発生を防止し、処理時
間の短縮を図つたことを特徴とするもので、さら
に、脱油と上記処理を同一炉工程で行うことを特
徴とするものである。Detailed Description of the Invention The present invention relates to a method and apparatus for soft-nitriding sintered parts, which prevents the occurrence of dimensional defects due to volume expansion of the sintered parts to be treated, and shortens processing time. The present invention is characterized in that the oil removal and the above-mentioned treatment are performed in the same furnace process.
焼結部品は通気性があり、そのまま軟窒化処理
を施すと表面のみならず、内部の結晶粒界にも窒
化物が生成し、体積膨張による寸法不良品が生ず
る欠点がある。 Sintered parts have air permeability, and if they are subjected to nitrocarburizing treatment as they are, nitrides are generated not only on the surface but also at the internal grain boundaries, resulting in dimensional defects due to volumetric expansion.
本発明では軟窒化処理に先立つて脱油と、さら
に体積膨張を阻止するため、四三酸化鉄（Fe3
O4）生成による封孔を同一炉工程で行うもので
ある。 In the present invention, triiron tetroxide (Fe 3
O 4 ) generation and sealing are performed in the same furnace process.
さらに、軟窒化処理時に、上記Fe3O4とアンモ
ニア（NH3）雰囲気により生ずるH2Ｏおよび炉
に残存するH2Ｏによる処理時間の延長を除去す
るために、アンモニア雰囲気の除湿を行うもので
ある。 Furthermore, during soft nitriding treatment, the ammonia atmosphere is dehumidified in order to eliminate the prolongation of treatment time due to H 2 O generated by the Fe 3 O 4 and ammonia (NH 3 ) atmosphere and H 2 O remaining in the furnace. It is.
以下に本発明の装置の一実施例を図面について
詳細に説明する。 An embodiment of the device of the present invention will be described in detail below with reference to the drawings.
１はレトルト炉であり、炉天井部にフアン２が
設けられ、さらに蒸気の供給管路３及びアンモニ
ア雰囲気の供給管路４が切換え供給自在に連結さ
れている。 Reference numeral 1 designates a retort furnace, which is provided with a fan 2 on the furnace ceiling, and further connected to a steam supply pipe 3 and an ammonia atmosphere supply pipe 4 so as to be able to switch and supply freely.
さらに炉床部には排気管路５及び循環管路６が
切換え自在に連結されている。図中７は排気管路
５に設けられた圧力調整器、８はアフターバーナ
ーである。 Further, an exhaust pipe line 5 and a circulation pipe line 6 are connected to the hearth portion in a switchable manner. In the figure, 7 is a pressure regulator provided in the exhaust pipe 5, and 8 is an afterburner.
さらに、上記循環管路６が冷却装置１０及び除
湿装置９を介して上記アンモニア雰囲気の供給管
路４に連結される。 Further, the circulation pipe 6 is connected to the ammonia atmosphere supply pipe 4 via a cooling device 10 and a dehumidifying device 9.
詳細に述べると、上記除湿装置９は水冷熱交換
タイプに構成されている。 To be more specific, the dehumidifying device 9 is constructed as a water-cooled heat exchange type.
すなわち、循環管路６が冷却装置１０で冷却さ
れ、さらに全体が水冷されて内部に冷却フイン１
１を有する除湿装置９の一端に導入され、その他
端からブロワー１２を介して上記アンモニア雰囲
気の供給管路４に連結される。 That is, the circulation pipe line 6 is cooled by the cooling device 10, and the whole is further water-cooled to have cooling fins 1 inside.
1, and is connected from the other end to the supply pipe 4 for the ammonia atmosphere via the blower 12.
図中１３はドレンである。 In the figure, 13 is a drain.
上記構成について本発明の方法の一実施例を説
明する。 An embodiment of the method of the present invention will be described with respect to the above configuration.
本発明では炉１内に焼結部品を装入し、つぎ
に、蒸気の供給管路３から蒸気（あるいは水）を
供給しつつ昇温が行われる（第２図Ａ）。 In the present invention, a sintered part is charged into the furnace 1, and then the temperature is raised while supplying steam (or water) from the steam supply pipe 3 (FIG. 2A).
この過程にあつては焼結部品の表面及び内部に
ある油分が蒸発させられ、排気管路５を介して排
気され、アフターバーナー８で燃焼させられる。
なおこの燃焼は各種用途に再利用される。そし
て、500〜570℃に昇温し、そのまま蒸気加熱を行
う。 During this process, oil present on the surface and inside of the sintered part is evaporated, exhausted through the exhaust pipe 5, and burned in the afterburner 8.
This combustion is reused for various purposes. Then, the temperature is raised to 500 to 570°C, and steam heating is performed as it is.
その結果、蒸気中のO2が焼結部品に作用して
6FeO＋O2＝2Fe3O4 …(1)
により、内部の結晶粒界にFe3O4が生成され、封
孔が行われる（第２図Ｂ）。 As a result, O 2 in the steam acts on the sintered part, and Fe 3 O 4 is generated at the internal grain boundaries due to 6FeO + O 2 = 2Fe 3 O 4 (1), and sealing is performed. Figure 2B).
つぎに、蒸気の供給管路３からの蒸気の供給が
止められ、アンモニア雰囲気の供給管路４からア
ンモニア雰囲気が供給され、軟窒化処理が行われ
る。（第２図Ｃ）。すなわち、
2NH3→2N＋3H2 …(2)
の反応により得られる活性基のＮとFeを反応さ
せ、ε（Fe(2-3)Ｎ），γ′（Fe4Ｎ）を表面に生成させ
る。 Next, the supply of steam from the steam supply pipe 3 is stopped, an ammonia atmosphere is supplied from the ammonia atmosphere supply pipe 4, and soft nitriding treatment is performed. (Figure 2C). That is, the active group N obtained by the reaction 2NH 3 →2N+3H 2 (2) reacts with Fe, and ε(Fe (2-3) N) and γ'(Fe 4 N) are generated on the surface.
しかしながら、本発明では上記封孔処理時に生
成されたFe3O4に上記(2)式によるH2が反応し、炉
内にH2Ｏが生成される。 However, in the present invention, Fe 3 O 4 generated during the sealing process is reacted with H 2 according to the above formula (2), and H 2 O is generated in the furnace.
Fe3O4＋4H2→3Fe＋4H2Ｏ …(3)
上記H2Ｏが数Kg程度の少量であれば還元と窒
化は同時に行われ、20〜40分で２〜3μの窒化層
が得られる。 Fe 3 O 4 +4H 2 →3Fe+4H 2 O (3) If the above-mentioned H 2 O is a small amount of about several kg, reduction and nitriding are performed simultaneously, and a nitrided layer of 2 to 3 μm can be obtained in 20 to 40 minutes.
しかし、焼結部品は反応面積が大きく、量産条
件では露点が高くなり、還元反応が抑制され、さ
らに、上記(2)式のNH3の分解も抑制され、処理
に長時間を必要とし、さらに長時間処理により内
部に窒化物が生成される可能性があり、この対策
としてNH3量を増加させると不経済である。 However, sintered parts have a large reaction area, and under mass production conditions, the dew point will be high, suppressing the reduction reaction, and also suppressing the decomposition of NH 3 in equation (2) above, requiring a long processing time, and There is a possibility that nitrides may be generated internally due to long-term processing, and increasing the amount of NH 3 as a countermeasure to this problem is uneconomical.
実験の結果では上記露点は低いほどよいが、実
用上40℃以下に制御すべきであることが判明し
た。 The results of experiments show that the lower the dew point, the better, but it has been found that it should be controlled to 40°C or less for practical purposes.
そこで、本発明では上記アンモニア雰囲気を循
環管路６から冷却装置１０を通して除湿装置９に
導き、冷却及び除湿したのち、ブロワー１２によ
り、アンモニア雰囲気の供給管路４に循環させた
ものである。 Therefore, in the present invention, the ammonia atmosphere is guided from the circulation pipe 6 through the cooling device 10 to the dehumidifier 9, cooled and dehumidified, and then circulated to the ammonia atmosphere supply pipe 4 by the blower 12.
その結果、露点を強制的に下げることができ処
理時間の短縮と、体積膨張による寸法不良品の発
生を防止できたものである。 As a result, the dew point can be forcibly lowered, processing time can be shortened, and dimensional defects due to volume expansion can be prevented.
第３図には本発明の方法及び装置で処理した焼
結部品の顕微鏡写真（400倍）が示されている。 FIG. 3 shows a micrograph (400x magnification) of a sintered part treated with the method and apparatus of the invention.
すなわち、内部の結晶粒界にはFe3O4１５が生
成されて封孔が行われ、表面には均一にFe(2-3)Ｎ
層１６が生成され、該Fe(2-3)Ｎ層１６が内部に生
成されていないことがわかる。 That is, Fe 3 O 4 15 is generated at the internal grain boundaries to seal the pores, and Fe (2-3) N is uniformly formed on the surface.
It can be seen that the layer 16 is formed, but the Fe (2-3) N layer 16 is not formed inside.
上記のごとく、本発明の処理方法によれば、内
部に窒化物が生成されることがないため、体積膨
張による寸法不良品が発生することがないもので
ある。 As described above, according to the processing method of the present invention, since nitrides are not generated inside, dimensional defects due to volumetric expansion will not occur.
さらに本発明ではFe3O4による封孔後、アンモ
ニア雰囲気を供給することによる露点の上昇を除
湿により強制的に下げるため、アンモニア雰囲気
の分解が抑制されることがなく、処理時間を延長
する必要がないものである。 Furthermore, in the present invention, after sealing with Fe 3 O 4 , the increase in dew point caused by supplying an ammonia atmosphere is forcibly lowered by dehumidification, so the decomposition of the ammonia atmosphere is not suppressed and it is necessary to extend the processing time. There is no such thing.
さらに本発明の装置によれば、脱油、封孔及び
軟窒化処理を同一炉工程で行うことができ、経済
的かつ極めて便利である効果を得ることができる
ものである。 Further, according to the apparatus of the present invention, deoiling, sealing, and nitrocarburizing can be performed in the same furnace process, and economical and extremely convenient effects can be obtained.
図面は本発明の一実施例を示すもので、第１図
は装置の全体回路図、第２図は処理工程を示す温
度曲線図、第３図は被処理品である焼結部品の結
晶の構造を示す顕微鏡写真（X400）である。
１……レトルト炉、３……（蒸気の）供給管
路、４……（アンモニア雰囲気の）供給管路、５
……排気管路、６……循環管路、９……除湿装
置。
The drawings show one embodiment of the present invention, and Fig. 1 is an overall circuit diagram of the device, Fig. 2 is a temperature curve diagram showing the processing steps, and Fig. 3 is a diagram of crystals of a sintered part, which is an article to be processed. This is a micrograph (X400) showing the structure. 1... Retort furnace, 3... (steam) supply pipe, 4... (ammonia atmosphere) supply pipe, 5
...Exhaust pipe line, 6...Circulation pipe line, 9...Dehumidifier.
Claims (1)
昇温して油分を蒸発及び排出し、さらに500〜570
℃で蒸気加熱して四三化鉄生成による封孔を行
い、つづいて同炉内に蒸気にかえてアンモニア雰
囲気を供給し、該アンモニア雰囲気を炉外で冷却
及び除湿して炉内に循環させて軟窒化処理を施す
ことを特徴とする焼結部品の軟窒化処理方法。 ２ 炉天井部に蒸気及びアンモニア雰囲気の供給
管路が切換え供給自在に連結され、炉適位置には
排気及び循環管路が切換え自在に連結され、該循
環管路が冷却及び除湿装置を介して上記アンモニ
ア雰囲気の供給管路に連結されてなることを特徴
とする焼結部品の軟窒化処理装置。[Claims] 1. A sintered part is placed in a furnace, heated while supplying steam to evaporate and discharge oil, and further heated to a temperature of 500 to 570
The pores are sealed by steam heating at ℃ to produce triferric iron, then an ammonia atmosphere is supplied into the furnace instead of steam, and the ammonia atmosphere is cooled and dehumidified outside the furnace and circulated inside the furnace. A nitrocarburizing method for sintered parts, the method comprising nitrocarburizing a sintered part. 2 Supply pipes for steam and ammonia atmosphere are connected to the furnace ceiling so that they can be switched and supplied, and exhaust and circulation pipes are connected to the furnace ceiling so that they can be switched and supplied, and the circulation pipes are connected to the furnace ceiling so that they can be switched and supplied. A nitrocarburizing treatment apparatus for sintered parts, characterized in that the apparatus is connected to the ammonia atmosphere supply pipe line.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4015284A JPS60186489A (en) | 1984-03-02 | 1984-03-02 | Soft nitration for sintered part and device therefor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4015284A JPS60186489A (en) | 1984-03-02 | 1984-03-02 | Soft nitration for sintered part and device therefor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS60186489A JPS60186489A (en) | 1985-09-21 |
| JPH0470391B2 true JPH0470391B2 (en) | 1992-11-10 |
Family
ID=12572790
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4015284A Granted JPS60186489A (en) | 1984-03-02 | 1984-03-02 | Soft nitration for sintered part and device therefor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS60186489A (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5312735A (en) * | 1976-07-22 | 1978-02-04 | Midland Ross Corp | Surface hardening of metallic sintered compacts |
| JPS5819414A (en) * | 1981-07-28 | 1983-02-04 | Riken Corp | Sliding member and its manufacture |
| JPS5837155A (en) * | 1981-08-28 | 1983-03-04 | Riken Corp | Sliding member |
-
1984
- 1984-03-02 JP JP4015284A patent/JPS60186489A/en active Granted
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5312735A (en) * | 1976-07-22 | 1978-02-04 | Midland Ross Corp | Surface hardening of metallic sintered compacts |
| JPS5819414A (en) * | 1981-07-28 | 1983-02-04 | Riken Corp | Sliding member and its manufacture |
| JPS5837155A (en) * | 1981-08-28 | 1983-03-04 | Riken Corp | Sliding member |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS60186489A (en) | 1985-09-21 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EXPY | Cancellation because of completion of term |