JP2881111B2 - Steel nitriding method - Google Patents
Steel nitriding methodInfo
- Publication number
- JP2881111B2 JP2881111B2 JP6135715A JP13571594A JP2881111B2 JP 2881111 B2 JP2881111 B2 JP 2881111B2 JP 6135715 A JP6135715 A JP 6135715A JP 13571594 A JP13571594 A JP 13571594A JP 2881111 B2 JP2881111 B2 JP 2881111B2
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- Prior art keywords
- nitriding
- steel
- gas
- temperature
- atmosphere
- Prior art date
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Description
【０００１】[0001]
【産業上の利用分野】本願発明は鋼の表面に窒化層を形
成して耐摩耗性等を向上させる鋼の窒化方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for nitriding steel which forms a nitrided layer on the surface of the steel to improve wear resistance and the like.
【０００２】[0002]
【従来の技術】耐摩耗性、耐食性、疲労強度等の機械的
性質を向上させる目的で、鋼の表面に窒化物の層を形成
する窒化法あるいは、浸炭窒化法として従来採用されて
きた方法は次のようなものである。 （イ） ＮａＣＮ、ＫＣＮＯ等のシアン系溶融塩による
方法（タフトライド法） （ロ） グロー放電による窒化（イオン窒化） （ハ） アンモニアまたはアンモニアと炭素源を有する
ガス（例えばＲＸガス）との混合ガスによる窒化（ガス
窒化、ガス軟窒化）2. Description of the Related Art For the purpose of improving mechanical properties such as wear resistance, corrosion resistance, fatigue strength and the like, a method conventionally used as a nitriding method for forming a nitride layer on the surface of steel or a carbonitriding method is as follows. It looks like this: (A) Method using cyanide molten salt such as NaCN, KCNO, etc. (Tufftride method) (b) Glow discharge nitriding (ion nitriding) (c) Ammonia or a mixed gas of ammonia and a gas having a carbon source (eg, RX gas) By gas (gas nitriding, gas nitrocarburizing)
【０００３】これらのうち、（イ）の方法は、有害な溶
融塩を用いるので作業環境、廃棄物処理等の点で将来的
に好ましくない。また、（ロ）の方法は、低真空のＮ2
＋Ｈ2 雰囲気中でグロー放電により窒化するもので、ス
パッタリングに伴う清浄化作用により酸化皮膜の影響は
少なくなるが、局部的な温度差による窒化ムラが発生し
やすい。また、この方法は、処理物の形状寸法に制約が
大きく、コスト高となるという問題点がある。さらに、
上記（ハ）の方法は、窒化ムラが生じやすい等、処理の
安定性に問題があり、しかも深い窒化層を得るためには
長時間を要するという問題点もある。[0003] Among them, the method (a) uses a harmful molten salt, and therefore is not preferable in the future in terms of working environment, waste disposal, and the like. The method (b) is based on low vacuum N 2
Nitrogen is nitrided by glow discharge in a + H 2 atmosphere. The effect of the oxide film is reduced due to the cleaning effect accompanying sputtering, but nitriding unevenness due to a local temperature difference is likely to occur. In addition, this method has a problem that the shape and size of the processed object are greatly restricted, and the cost is increased. further,
The method (c) has a problem in the stability of the treatment, such as uneven nitridation, and also requires a long time to obtain a deep nitride layer.
【０００４】一般に、鋼は５００℃以上の温度で窒化さ
れるが、鋼表面層への窒素の吸着、拡散には、金属表面
の活性度が高いことが必要で、有機，無機系の汚れは勿
論、酸化皮膜やＯ2 の吸着皮膜が存在しないことが望ま
しい。また、酸化皮膜の存在は、窒化ガスであるアンモ
ニアの解離度を助長する点でも好ましくない。しかしな
がら、実際にはガス窒化法において酸化皮膜の形成を防
止することは不可能であり、例えばクロムを多量に含ま
ない肌焼鋼や構造用鋼の場合でも４００℃〜５００℃の
温度でも、ＮＨ3 やＮＨ3 ＋ＲＸの雰囲気下でも薄い酸
化物質が形成される。クロム等酸素との親和力の大きい
元素を多量に含む鋼種ではこの傾向が更に強くなる。[0004] Generally, steel is nitrided at a temperature of 500 ° C or higher, but the adsorption and diffusion of nitrogen to the steel surface layer requires a high activity on the metal surface. of course, it is desirable that the adsorption film of the oxide film and O 2 is not present. Further, the presence of the oxide film is not preferable in that it promotes the dissociation degree of ammonia, which is a nitriding gas. However, it is actually impossible to prevent the formation of an oxide film by the gas nitriding method. For example, even in the case of case hardening steel or structural steel not containing a large amount of chromium, even at a temperature of 400 ° C. to 500 ° C., NH Even in an atmosphere of 3 or NH 3 + RX, a thin oxide substance is formed. This tendency is further enhanced in steel types containing a large amount of elements having a high affinity for oxygen such as chromium.
【０００５】このような酸化物の形成は、同一部品でも
表面状態や加工条件等によって変化し、結果的に不均一
な窒化層を形成していた。典型的な例として、たとえば
オーステナイト系のステンレスの冷間加工品等の場合
は、処理炉に挿入する前にフッ硝酸により洗浄して表面
の不働態皮膜を完全に除去しても、満足な窒化層を形成
するのはほとんど不可能である。なお、窒化ムラについ
てはガス軟窒化のみでなく、窒化鋼やステンレス鋼に対
するアンモニアのみによる窒化（ガス窒化）においても
同様に発生する。また、通常の構造用鋼の場合でも歯車
のごとき形状の複雑な部品の場合窒化ムラが発生し易い
という基本的な問題がある。The formation of such an oxide varies depending on the surface condition, processing conditions, and the like even in the same part, and as a result, a non-uniform nitride layer is formed. As a typical example, for example, in the case of a cold-worked austenitic stainless steel, even if it is washed with hydrofluoric nitric acid before being inserted into the processing furnace to completely remove the passivation film on the surface, satisfactory nitriding can be achieved. It is almost impossible to form a layer. In addition, the non-uniform nitriding occurs not only in gas nitrocarburizing but also in nitriding (gas nitriding) of nitrided steel or stainless steel with only ammonia. Further, even in the case of ordinary structural steel, there is a basic problem that in the case of a component having a complicated shape such as a gear, nitriding unevenness easily occurs.
【０００６】上記のようなガス窒化、ガス軟窒化の本質
的な問題点を改良する手段として、塩化ビニル樹脂を処
理物（ワーク）とともに炉に挿入する方法や、ＣＨ3 Ｃ
ｌ等をふりかけて２００〜３００℃に加熱し、ＨＣｌを
発生させて酸化物の発生を防止するとともにその除去を
はかる方法、あるいは予め表面にメッキを施して酸化物
を抑制する方法等が過去に提唱されたことがあるが、ほ
とんど実用化されていないのが現状である。ＨＣｌによ
って鋼表面にＦｅＣｌ2 、ＦｅＣｌ3 等の塩化物が析出
するが、これらは窒化温度以下の温度で極めて脆く、し
かも昇華、蒸発しやすいため、塩化物膜は形成されず、
若干の酸化皮膜抑制効果はあるものの取扱いそのものの
煩雑さや炉材の損傷が著しいことと相まって実用的には
有効とはいえないのである。As means for improving the essential problems of gas nitriding and gas nitrocarburizing as described above, a method of inserting a vinyl chloride resin into a furnace together with a processed material (work), a method of CH 3 C
In the past, a method of sprinkling 1 or the like and heating to 200 to 300 ° C. to generate HCl to prevent the generation of oxides and remove them, or a method of plating oxides on the surface in advance to suppress oxides, etc., have been used in the past. Although it has been proposed, it has hardly been put to practical use. HCl precipitates chlorides such as FeCl 2 and FeCl 3 on the steel surface, but these are extremely brittle at temperatures lower than the nitriding temperature, and are easily sublimated and evaporated, so that chloride films are not formed.
Although it has a slight oxide film suppression effect, it is not practically effective due to the complicated handling itself and the remarkable damage to the furnace material.
【０００７】[0007]
【発明が解決しようとする課題】本発明は上記事情に鑑
み、窒化処理前洗浄後の残存有機無機異物や、被処理物
の酸化皮膜による窒化ムラ等の発生を効果的に解消する
こと、およびこの目的を達成するため、処理プロセス上
シンプルなシステムを提供することを課題としている。SUMMARY OF THE INVENTION In view of the above circumstances, it is an object of the present invention to effectively eliminate the occurrence of organic and inorganic foreign matters remaining after cleaning before nitriding treatment and the occurrence of uneven nitriding due to an oxide film on an object to be treated. In order to achieve this object, it is an object to provide a simple system in the processing process.
【０００８】[0008]
【課題を解決するための手段】上記課題を解決するた
め、この発明の鋼の窒化方法は、鋼の表面に窒素を反応
させて硬質の窒化層を形成する鋼の窒化方法において、
鋼を脱脂洗浄したのち、フッ素を含む反応ガス雰囲気中
に加熱保持して表面層にフッ化物膜を生成し、窒化雰囲
気中で加熱して窒化層を形成するという構成をとる。こ
こで、窒化方法とは、浸炭窒化法、酸窒化法、浸硫窒化
法等の各種窒化法を包含する。Means for Solving the Problems In order to solve the above problems, a method for nitriding steel according to the present invention is directed to a method for nitriding steel in which a hard nitrided layer is formed by reacting nitrogen on the surface of steel.
After the steel is degreased and cleaned, a configuration is adopted in which a fluoride film is formed on the surface layer by heating and holding in a fluorine-containing reaction gas atmosphere, and heating is performed in a nitriding atmosphere to form a nitride layer. Here, the nitriding method includes various nitriding methods such as a carbonitriding method, an oxynitriding method, and a sulphonitriding method.
【０００９】本発明で使用されるフッ素含有反応ガスと
しては、例えばＮＦ3 ，ＢＦ3 ，ＣＦ4 ，ＳＦ6 ，Ｆ2
等のフッ素化合物もしくはフッ素を含むハロゲンガスが
ある。これらフッ素化合物のうち、反応性、取扱い性等
の面でＮＦ3 が最も優れており、実用的である。上記フ
ッ素化合物を含有する反応ガス雰囲気下で鋼の被加工物
を例えばＮＦ3 の場合１５０〜３５０℃の温度に加熱保
持し、被加工物を表面処理した後、公知の窒化用ガス、
例えばアンモニアを用いて窒化処理（または浸炭窒化処
理）を行うのである。フッ素を含む反応ガス雰囲気のフ
ッ素化合物濃度は例えば１０００〜１００００ｐｐｍで
あり、該雰囲気中での保持時間は、鋼種、ワークの形状
寸法、加熱温度等に応じて適当な時間を選べばよく、通
常は十数分〜数十分である。As the fluorine-containing reaction gas used in the present invention, for example, NF 3 , BF 3 , CF 4 , SF 6 , F 2
And halogen gas containing fluorine. Among these fluorine compounds, NF 3 is the most excellent in terms of reactivity, handleability, and the like, and is practical. Under a reaction gas atmosphere containing the fluorine compound, the workpiece of steel is heated and maintained at a temperature of 150 to 350 ° C. in the case of NF 3 , for example, and after the workpiece is subjected to surface treatment, a known nitriding gas,
For example, nitriding (or carbonitriding) is performed using ammonia. The concentration of the fluorine compound in the reaction gas atmosphere containing fluorine is, for example, 1000 to 10000 ppm, and the holding time in the atmosphere may be appropriately selected according to the type of steel, the shape and size of the work, the heating temperature, and the like. Ten minutes to several tens of minutes.
【００１０】本発明の方法をより具体的に説明すると、
鋼製のワークを例えば脱脂洗浄したのち、図１に示すよ
うな熱処理炉１に挿入する。この炉１は外殻２内に設け
たヒータ３の内側にステンレス製内容器４を入れたピッ
ト炉で、ガス導入管５と排気管６が挿入されている。ガ
ス導入管５にはボンベ１５，１６から流量計１７，バル
ブ１８等を経由してガスが供給される。内部の雰囲気は
モータ７で回転するファン８によって攪拌される。ワー
ク１０は金鋼製のコンテナ１１に入れて炉内に挿入され
る。図中、１３は真空ポンプ、１４は除害装置である。
この炉中にフッ素を含む反応ガス、例えばＮＦ3 とＮ2
の混合ガスを導入し、所定の反応温度に加熱する。ＮＦ
3 は２５０〜４００℃の温度で活性基のＦ分を発生し、
このＦが表面に残存している有機無機の異物を除去する
と共に、鋼表面のＦｅ，Ｃｒ素地あるいはＦｅＯ，Ｆｅ
3 Ｏ4 ，Ｃｒ2 Ｏ3 等の酸化物と迅速に反応して、例え
ば下記の式に示すごとく、表面にＦｅＦ2 ，ＦｅＦ3 ，
ＣｒＦ2 ，ＣｒＦ4 等の化合物を金属組織中に含むごく
薄いフッ化膜が形成される。[0010] The method of the present invention will be described more specifically.
After a steel work is degreased and cleaned, for example, it is inserted into a heat treatment furnace 1 as shown in FIG. The furnace 1 is a pit furnace in which a stainless steel inner container 4 is placed inside a heater 3 provided in an outer shell 2, and a gas introduction pipe 5 and an exhaust pipe 6 are inserted therein. Gas is supplied to the gas introduction pipe 5 from cylinders 15 and 16 via a flow meter 17 and a valve 18. The internal atmosphere is agitated by a fan 8 rotated by a motor 7. The work 10 is inserted into a furnace in a container 11 made of steel. In the figure, 13 is a vacuum pump and 14 is a harm removal device.
Reaction gas containing fluorine such as NF 3 and N 2
And heated to a predetermined reaction temperature. NF
3 generates an F component of the active group at a temperature of 250 to 400 ° C.,
This F removes organic and inorganic foreign substances remaining on the surface, and removes Fe, Cr substrate or FeO, Fe on the steel surface.
It reacts quickly with oxides such as 3 O 4 , Cr 2 O 3 and the like, for example, as shown in the following formula, FeF 2 , FeF 3 ,
A very thin fluoride film containing a compound such as CrF 2 or CrF 4 in the metal structure is formed.
【００１１】このとき、本発明では、ワーク１０を脱脂
洗浄したのちフッ化処理するため、ワーク１０表面の余
分な油分や塵埃等が除去されて清浄化され、より均一な
窒化層を迅速に得ることができる。なお、本発明におい
て脱脂洗浄とは、フロン洗浄やアセトン洗浄等の溶剤系
洗浄だけでなく、アルカリ洗浄等の水系洗浄も含む趣旨
である。[0011] At this time, in the present invention, in order to fluorinated After degreasing the workpiece 10, is extra oil and dust are removed clean the workpiece 10 surface, quickly uniform nitride layer Ri yo Can be obtained . Na us, the degreasing in the present invention, not only the solvent-based cleaning such Freon cleaning and acetone washing, is intended to embrace aqueous cleaning, such as alkali washing.
【００１２】[0012]
【化１】 ＦｅＯ＋２Ｆ→ＦｅＦ2 ＋１／２Ｏ2 ＣｒＯ3 ＋４Ｆ→２ＣｒＦ2 ＋３／２Ｏ2 Embedded image FeO + 2F → FeF 2 + 1 / 2O 2 CrO 3 + 4F → 2CrF 2 + 3 / 2O 2
【００１３】この反応により、ワーク表面の酸化皮膜は
フッ化膜に変換され、表面に吸着されていたＯ2 も除去
される。そして、このようなフッ化膜は、Ｏ2 ，Ｈ2 ，
Ｈ2Ｏが存在しない場合６００℃以下の温度で安定であ
って後続の窒化処理温度までの間における金属素地への
酸化皮膜の形成やＯ2 の吸着を防止すると考えられる。By this reaction, the oxide film on the work surface is converted into a fluoride film, and O 2 adsorbed on the surface is also removed. And such a fluoride film is made of O 2 , H 2 ,
When H 2 O is not present, it is considered to be stable at a temperature of 600 ° C. or less and prevent the formation of an oxide film on the metal substrate and the adsorption of O 2 until the subsequent nitriding temperature.
【００１４】このように、フッ素を含有する反応ガスで
処理したワークは、例えばＮ2 雰囲気等の非酸化性雰囲
気下で引続き４８０〜７００℃の窒化温度に加熱され、
ＮＨ3 あるいはＮＨ3 と炭素源を有するガス（例えばＲ
Ｘガス）との混合ガスを添加すると、フッ化膜はＨ2 ま
たは微量の水分によって例えば下記の式のように還元あ
るいは破壊され、活性な金属素地が形成されると推測さ
れる。Thus, the workpiece treated with the fluorine-containing reaction gas is heated to a nitriding temperature of 480 to 700 ° C. in a non-oxidizing atmosphere such as an N 2 atmosphere.
NH 3 or a gas containing NH 3 and a carbon source (for example, R 3
When a mixed gas with X gas is added, the fluoride film is reduced or destroyed by H 2 or a small amount of water, for example, as in the following formula, and it is presumed that an active metal base is formed.
【００１５】[0015]
【化２】 ＣｒＦ4 ＋２Ｈ2 →Ｃｒ＋４ＨＦ ２ＦｅＦ3 ＋３Ｈ2 →２Ｆｅ＋６ＨＦEmbedded image CrF 4 + 2H 2 → Cr + 4HF 2FeF 3 + 3H 2 → 2Fe + 6HF
【００１６】このように、活性な金属素地が形成される
と同時に活性基のＮが吸着されて金属内に侵入、拡散し
てゆき、その結果、表面にＣｒＮ，Ｆｅ2 Ｎ，Ｆｅ
3 Ｎ，Ｆｅ4 Ｎ等の窒化物を含有する化合物層が形成さ
れる。As described above, at the same time when the active metal matrix is formed, N of the active group is adsorbed and penetrates and diffuses into the metal. As a result, CrN, Fe 2 N, Fe
3 N, compound layer containing a nitride such as Fe 4 N are formed.
【００１７】このような化合物層が形成されるのは、従
来の窒化法でも同様であるが、従来法では、常温より窒
化温度まで昇温する間に形成される酸化皮膜や、このと
き吸着されるＯ2 分によって表面の活性度が低下してい
るので、Ｎの表面吸着の度合いが低く、不均一である。
また、このような不均一性は、ＮＨ3 の分解の度合いを
炉内で均一に保つことが実際上困難であることによって
も拡大されるのである。本発明ではワーク表面における
Ｎの吸着が均一かつ迅速に行われるので、上記のような
問題は生じない。本プロセスにおいて、フッ素を含む反
応ガス雰囲気中での加熱温度および窒化雰囲気中での加
熱温度が６００℃以下である場合には、フッ化膜が６０
０℃以下で安定な不働態膜を形成するため、金属製の炉
材表面に形成されたフッ化膜が安定な不働態膜となり、
炉材の損傷がきわめて少なくなるという効果を奏する。The formation of such a compound layer is the same as in the conventional nitriding method. However, in the conventional method, the oxide film formed during the temperature rise from the room temperature to the nitriding temperature, Since the surface activity is reduced by the amount of O 2, the degree of N adsorption on the surface is low and non-uniform.
Such non-uniformity is also magnified by the fact that it is practically difficult to keep the degree of decomposition of NH 3 uniform in the furnace. In the present invention, since the adsorption of N on the work surface is performed uniformly and quickly, the above-mentioned problem does not occur. In the present process, when the heating temperature in the reaction gas atmosphere containing fluorine and the heating temperature in the nitriding atmosphere are 600 ° C. or less, the fluoride film becomes 60 ° C.
In order to form a stable passive film at 0 ° C. or less, the fluoride film formed on the surface of the metal furnace material becomes a stable passive film,
This has the effect of significantly reducing damage to the furnace material.
【００１８】上記本発明の操作プロセス上の大きな特徴
の一つは、フッ化膜を形成させる反応ガスとしてＮＦ3
を用いることにある。すなわち、ＮＦ3 のような常温で
反応性がなく、ガス状の取扱い易い物質を用いることに
より、メッキ処理や固体や液体のＰＶＣ等の塩素源を用
いる等の方法に比べ、処理が連続操作となる等プロセス
がシンプルになるという効果を奏する。また、タフトラ
イド方式は、窒化層の付き廻り性や疲労強度の向上への
効果等ですぐれた方法といえるが作業環境、公害設備等
への大きな費用がかかる点で将来にひらけた方法とはい
えない。これに対し、本発明のプロセスでは処理廃ガス
を除害化するための簡易な装置だけで充分であり、タフ
トライド方式と同等以上の付き廻り性で窒化ムラの排除
が可能となるという効果を奏するのである。そのほか、
タフトライド方式が浸窒と同時に浸炭も進行するのに比
べて、純窒化のみも可能であるという利点もある。One of the major characteristics of the operation process of the present invention is that NF 3 is used as a reaction gas for forming a fluoride film.
Is to use. That is, by using a gaseous, non-reactive material such as NF 3 which is not reactive at normal temperature, the treatment is a continuous operation compared with a plating treatment or a method using a chlorine source such as solid or liquid PVC. This has the effect of simplifying the process. In addition, the tuftride method can be said to be an excellent method due to the effect of improving the throwing power of the nitride layer and the improvement of the fatigue strength, but it can be said to be a method that has opened up in the future because it requires a large cost for the working environment, pollution equipment and the like. Absent. On the other hand, in the process of the present invention, only a simple apparatus for detoxifying the processing waste gas is sufficient, and there is an effect that it is possible to eliminate non-uniform nitriding with a throwing power equal to or higher than that of the tuftride method. It is. others,
Compared with the tuftride method in which carburization proceeds simultaneously with nitriding, there is an advantage that only pure nitriding is possible.
【００１９】[0019]
【実施例１および比較例１】ＳＵＳ３０５系加工硬化品
（ネジ）をフロン洗浄したのち、図１に示すような処理
炉１に入れ，ＮＦ3 を５０００ｐｐｍ含有するＮ2 ガス
雰囲気で３００℃で１５分間保持した。その後５３０℃
に加熱し、５０％ＮＨ3 ＋５０％Ｎ2 の混合ガスを炉内
に導入して３時間窒化処理を行い、しかるのち空冷して
取り出した。Example 1 and Comparative Example 1 A SUS305-based work-hardened product (screw) was washed with Freon, placed in a processing furnace 1 as shown in FIG. 1, and placed in a N 2 gas atmosphere containing 5000 ppm of NF 3 at 300 ° C. for 15 hours. Hold for minutes. Then 530 ° C
Then, a mixed gas of 50% NH 3 + 50% N 2 was introduced into the furnace, and a nitriding treatment was performed for 3 hours.
【００２０】得られたワークの窒化層の厚みは均一で、
その硬度は、基材の部分が２６０〜２８０Ｈｖであるの
に対し、表面硬度が１１００〜１３００Ｈｖであった。The thickness of the nitrided layer of the obtained work is uniform,
The hardness of the substrate was 260 to 280 Hv, while the surface hardness was 1100 to 1300 Hv.
【００２１】これに対し、比較例１として同じワークを
フロン洗浄後フッ硝酸処理したのち上記炉に入れ、７５
％ＮＨ3 中で５３０℃および５７０℃で３時間加熱した
が、いずれの処理でも形成された窒化層の厚みに大きな
バラツキがあり、全く窒化層が形成されていない部分が
多かった。On the other hand, as Comparative Example 1, the same work was washed with chlorofluorocarbon and then treated with hydrofluoric-nitric acid.
After heating at 530 ° C. and 570 ° C. for 3 hours in% NH 3 , the thickness of the nitrided layer formed by any of the treatments varied greatly, and there were many portions where no nitrided layer was formed.
【００２２】上記実施例１と比較例１（５７０℃）につ
いて、ＥＰＭＡで表面層の元素分析を行った結果を図２
に示す。また、両者の表面付近の顕微鏡組織を図３およ
び図４に示す。FIG. 2 shows the results of elemental analysis of the surface layer by EPMA for Example 1 and Comparative Example 1 (570 ° C.).
Shown in 3 and 4 show the microscopic structures near the surfaces of both.
【００２３】[0023]
【実施例２】ＳＵＳ３０５のタッピングネジをアセトン
洗浄後図１に示す炉にいれＮＦ3 を５０００ｐｐｍ含有
するＮ2 雰囲気下で２８０℃１５分間保持その後４７０
℃に昇温しＮ2 ＋９０％Ｈ2 下で３０分間保持した後２
０％ＮＨ3 ＋８０％ＲＸにて８時間窒化して取り出し
た。Example 2 After washing the tapping screw of SUS305 with acetone, the tapping screw was put in the furnace shown in FIG. 1 and kept at 280 ° C. for 15 minutes in an N 2 atmosphere containing 5,000 ppm of NF 3, and then 470 mm.
Temperature and kept under N 2 + 90% H 2 for 30 minutes.
It was taken out by nitriding with 0% NH 3 + 80% RX for 8 hours.
【００２４】４０〜５０μｍの窒化層がネジの表面全体
に形成されていたが、表面硬度はＨｖ＝６５０〜７５０
であり、この窒化層は５％硫酸に対して、基材とそれほ
ど遜色のない耐食性を示した。Although a nitride layer of 40 to 50 μm was formed on the entire surface of the screw, the surface hardness was Hv = 650 to 750.
This nitrided layer exhibited corrosion resistance to 5% sulfuric acid that was not inferior to that of the substrate.
【００２５】[0025]
【実施例３および比較例２】窒化鋼（ＳＡＣＭ１）を洗
浄後、図１に示す炉に入れ、ＮＦ3 ５０００ｐｐｍを含
むＮ2 ガス中で２８０℃にて２０分間保持し、その後５
５０℃に昇温して７５％ＮＨ3 中で１２時間加熱したと
ころ、得られた窒化層の厚さが０．４２ｍｍであった。
比較例２として従来法で同じ部品を窒化した時の窒化層
の厚さは０．２８ｍｍであった。Example 3 and Comparative Example 2 After cleaning the nitrided steel (SACM1), it was placed in the furnace shown in FIG. 1 and kept in N 2 gas containing 5000 ppm of NF 3 at 280 ° C. for 20 minutes, and then
After heating to 50 ° C. and heating in 75% NH 3 for 12 hours, the thickness of the obtained nitrided layer was 0.42 mm.
As Comparative Example 2, when the same component was nitrided by the conventional method, the thickness of the nitrided layer was 0.28 mm.
【００２６】[0026]
【実施例４】構造用炭素鋼（Ｓ４５Ｃ）の金型部品を洗
浄後、ＮＦ3 ガスを５０００ｐｐｍ含有する雰囲気下で
３００℃で２０分間保持し、その後５３０℃に昇温して
ＮＨ3 ＋５０％ＲＸにて４時間処理した後、油冷して取
り出した。得られた窒化層の硬度は４５０〜４８０Ｈｖ
であった。このワークの回転曲げ疲労強度試験を行った
結果は４４ｋｇ／ｍｍ2 で従来のガス軟窒化品に較べて
同等またはそれ以上であった。Example 4 After cleaning the mold parts of the structural carbon steel (S45C), the parts were kept at 300 ° C. for 20 minutes in an atmosphere containing 5000 ppm of NF 3 gas, and then the temperature was raised to 530 ° C. and NH 3 + 50% After treatment with RX for 4 hours, the mixture was taken out with oil cooling. The hardness of the obtained nitrided layer is 450 to 480 Hv
Met. The result of the rotational bending fatigue strength test of this work was 44 kg / mm 2 , which was equal to or higher than that of a conventional gas nitrocarburized product.
【００２７】[0027]
【比較例３および４】エメリー研磨した熱間金型部品
（ＳＫＤ６１）をワークとして図１に示す炉に入れ、Ｎ
Ｆ3 を３０００ｐｐｍ含有するＮ2 雰囲気中で、３００
℃で１５〜２０分間加熱したのち、５７０℃まで加熱し
５０％ＮＨ3 ＋５０％Ｎ2 の混合ガスで３時間処理し
た。Comparative Examples 3 and 4 A hot die part (SKD61) polished by emery was placed as a work in the furnace shown in FIG.
In an N 2 atmosphere containing 3000 ppm of F 3 ,
After heating at 15 ° C. for 15 to 20 minutes, the mixture was heated to 570 ° C. and treated with a mixed gas of 50% NH 3 + 50% N 2 for 3 hours.
【００２８】同じ部品をフッ硝酸洗浄したのち、５７０
℃で３時間窒化処理したものの窒化膜は、最も厚いとこ
ろで９０〜１００μｍであり、バラツキが大きくしかも
面荒れがひどかった。After cleaning the same parts with hydrofluoric-nitric acid,
The nitrided film obtained by nitriding for 3 hours at a temperature of 90 ° C. had a thickness of 90 to 100 μm at the thickest point, and had large variations and severe surface roughness.
【００２９】[0029]
【発明の効果】以上の説明から明らかなように、本発明
の窒化法は従来のガス窒化、ガス軟窒化を改良するもの
で、均一な窒化層を迅速に得ることが可能となった。ま
た、鋼種、加工段階、前処理状態等の如何にかかわらず
良好な窒化層を得ることができ、穴やスリットを有する
部品でも窒化が可能である。さらに、オーステナイト系
ステンレス鋼のような窒化困難な鋼種に対しても、容易
に窒化できる等の利点がある。そのうえ、ワークを脱脂
洗浄したのちフッ化処理するため、ワーク表面の余分な
油分や塵埃等が除去されて清浄化され、より均一な窒化
層を迅速に得ることができる。 As is apparent from the above description, the nitriding method of the present invention is an improvement over conventional gas nitriding and gas nitrocarburizing, and has made it possible to quickly obtain a uniform nitrided layer. Also, a good nitrided layer can be obtained regardless of the type of steel, processing stage, pretreatment state, etc., and nitriding can be performed even on a component having holes or slits. Furthermore, there is an advantage that nitriding can be easily performed even on a steel type that is difficult to nitride such as austenitic stainless steel. Moreover, in order to fluorinated After degreasing the workpiece is cleaned extra oil and dust is removed in the work surface, a uniform nitrided layer Ri good can be obtained quickly.
【００３０】本発明の鋼の窒化法において、フッ素を含
む反応ガスが、ＮＦ3 含有ガスである場合には、ＮＦ3
のような常温で反応性がなく、ガス状の取扱い易い物質
を用いることにより、メッキ処理や固体や液体のＰＶＣ
等の塩素源を用いる等の方法に比べ、処理が連続操作と
なる等プロセスがシンプルになるという効果を奏する。
また、タフトライド方式では、窒化層の付き廻り性や疲
労強度の向上への効果等ですぐれた方法といえるが作業
環境、公害設備等への大きな費用がかかるが、本発明の
プロセスでは処理廃ガスを除害化するための簡易な装置
だけで充分であり、タフトライド方式と同等以上の付き
廻り性で窒化ムラの排除が可能となるという効果を奏す
る。そのほか、タフトライド方式が浸窒と同時に浸炭も
進行するのに比べて、純窒化のみも可能であるという利
点もある。In the method of nitriding steel according to the present invention, when the reaction gas containing fluorine is an NF 3 -containing gas, NF 3
By using a gaseous material that is not reactive at room temperature and is easy to handle, such as plating, solid or liquid PVC
As compared with a method using a chlorine source such as described above, there is an effect that the process becomes simple such as a continuous operation.
In addition, the tuftride method can be said to be an excellent method due to the effect of improving the throwing power of the nitride layer and the improvement of the fatigue strength, but it requires a large cost for the working environment, pollution equipment, and the like. It is sufficient to use only a simple device for detoxification, and it is possible to eliminate nitriding unevenness with a throwing power equal to or higher than that of the tuftride method. In addition, the tuftride method has an advantage that only pure nitriding is possible, as compared with the case where carburizing proceeds simultaneously with nitriding.
【００３１】また、本発明の鋼の窒化法において、フッ
素を含む反応ガス雰囲気中での加熱温度および窒化雰囲
気中での加熱温度が、６００℃以下である場合には、フ
ッ化膜が６００℃以下で安定な不働態膜を形成するた
め、金属製の炉材表面に形成されたフッ化膜が安定な不
働態膜となり、炉材の損傷がきわめて少なくなるという
効果を奏する。In the method of nitriding steel according to the present invention, when the heating temperature in the reaction gas atmosphere containing fluorine and the heating temperature in the nitriding atmosphere are 600 ° C. or less, the fluoride film is formed at 600 ° C. Since a stable passivation film is formed below, the fluoride film formed on the surface of the metal furnace material becomes a stable passivation film, and has an effect that damage to the furnace material is extremely reduced.
【図１】処理炉の１例をあらわす断面図である。FIG. 1 is a sectional view showing an example of a processing furnace.
【図２】元素分析結果を示すチャートである。FIG. 2 is a chart showing the results of elemental analysis.
【図３】この発明により処理された実施例１品の表面層
の金属組織写真である。FIG. 3 is a metallographic photograph of the surface layer of the product of Example 1 treated according to the present invention.
【図４】比較例１品の表面層の金属組織写真である。FIG. 4 is a photograph of the metal structure of the surface layer of the product of Comparative Example 1.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 友田 孝一 大阪府泉南郡阪南町尾崎285−１ 公団 尾崎14−402 (72)発明者 北野 憲三 大阪府河内長野市小山田町1498−１ (72)発明者 湊 輝男 和歌山県橋本市城山台３丁目38−２ (56)参考文献 特開 平６−299317（ＪＰ，Ａ) 特開 平６−145951（ＪＰ，Ａ) 特開 平５−195193（ＪＰ，Ａ) 特開 平４−187754（ＪＰ，Ａ) 特開 平３−44457（ＪＰ，Ａ) 特開 平５−59530（ＪＰ，Ａ) 特開 平４−358057（ＪＰ，Ａ) 特開 平４−187755（ＪＰ，Ａ) ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Koichi Tomoda 285-1 Ozaki, Hannan-cho, Sennan-gun, Osaka 14-402 Ozaki Public Corporation (72) Inventor Kenzo Kitano 1498-1, Koyamada-cho, Kawachinagano-shi, Osaka (72) Invention Person Teruo Minato 3-38-2, Shiroyamadai, Hashimoto City, Wakayama Prefecture (56) References JP-A-6-299317 (JP, A) JP-A-6-145951 (JP, A) JP-A-5-195193 (JP, A) JP-A-4-187754 (JP, A) JP-A-3-44457 (JP, A) JP-A-5-59530 (JP, A) JP-A-4-358057 (JP, A) JP-A-4 -187755 (JP, A)
Claims (3)
層を形成する鋼の窒化方法において、鋼を脱脂洗浄した
のち、フッ素を含む反応ガス雰囲気中に加熱保持して表
面層にフッ化物膜を生成し、窒化雰囲気中で加熱して窒
化層を形成することを特徴とする鋼の窒化方法。In a method of nitriding steel, a hard nitrided layer is formed by reacting nitrogen on the surface of steel. After the steel is degreased and cleaned, the steel is heated and held in a fluorine-containing reaction gas atmosphere, and the surface layer is fluorinated. Forming a nitride film and heating it in a nitriding atmosphere to form a nitrided layer.
スである請求項１記載の鋼の窒化方法。The method for nitriding steel according to claim 1, wherein
温度および窒化雰囲気中での加熱温度が、６００℃以下Temperature and heating temperature in nitriding atmosphere are 600 ° C or less
である請求項２記載の鋼の窒化方法。The method for nitriding steel according to claim 2, wherein
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6135715A JP2881111B2 (en) | 1994-06-17 | 1994-06-17 | Steel nitriding method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6135715A JP2881111B2 (en) | 1994-06-17 | 1994-06-17 | Steel nitriding method |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1177660A Division JPH089766B2 (en) | 1989-06-10 | 1989-07-10 | Steel nitriding method |
Related Child Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP8347019A Division JP3005953B2 (en) | 1996-12-26 | 1996-12-26 | Steel nitriding method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0754123A JPH0754123A (en) | 1995-02-28 |
| JP2881111B2 true JP2881111B2 (en) | 1999-04-12 |
Family
ID=15158195
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6135715A Expired - Lifetime JP2881111B2 (en) | 1994-06-17 | 1994-06-17 | Steel nitriding method |
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| Country | Link |
|---|---|
| JP (1) | JP2881111B2 (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH102336A (en) * | 1996-04-16 | 1998-01-06 | Koyo Seiko Co Ltd | Retainer for bearing and manufacture therefor |
| DE69841718D1 (en) * | 1997-04-03 | 2010-07-22 | Jtekt Corp | roller bearing |
| JP3699803B2 (en) * | 1997-05-09 | 2005-09-28 | 光洋精工株式会社 | Manufacturing method of bearing and bearing |
| JP3729061B2 (en) * | 2000-11-15 | 2005-12-21 | 松下電器産業株式会社 | Method for manufacturing circuit-formed substrate |
| EP1712658B1 (en) | 2004-02-04 | 2011-07-13 | Honda Motor Co., Ltd. | Method for surface treatment of metal material |
| JP4771718B2 (en) * | 2005-03-10 | 2011-09-14 | エア・ウォーターＮｖ株式会社 | Metal nitriding method |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH089766B2 (en) * | 1989-07-10 | 1996-01-31 | 大同ほくさん株式会社 | Steel nitriding method |
| JP2501062B2 (en) * | 1992-01-14 | 1996-05-29 | 大同ほくさん株式会社 | Nitriding method of nickel alloy |
| JP3023222B2 (en) * | 1991-08-31 | 2000-03-21 | 大同ほくさん株式会社 | Hard austenitic stainless steel screw and its manufacturing method |
| JP3026595B2 (en) * | 1990-11-20 | 2000-03-27 | 大同ほくさん株式会社 | Motor rotary shaft and its manufacturing method |
| JP3026596B2 (en) * | 1990-11-20 | 2000-03-27 | 大同ほくさん株式会社 | Crankshaft and its manufacturing method |
| JP2918716B2 (en) * | 1991-01-25 | 1999-07-12 | 大同ほくさん株式会社 | Method of nitriding steel |
| JPH0614951A (en) * | 1992-01-17 | 1994-01-25 | Kazuji Tanaka | Snore preventing device |
| JPH06299317A (en) * | 1993-04-08 | 1994-10-25 | Osaka Oxygen Ind Ltd | Nitriding or soft nitriding method for steel |
-
1994
- 1994-06-17 JP JP6135715A patent/JP2881111B2/en not_active Expired - Lifetime
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|---|---|
| JPH0754123A (en) | 1995-02-28 |
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