JPH06184727A - Method for hardening surface of part made of steel - Google Patents
Method for hardening surface of part made of steelInfo
- Publication number
- JPH06184727A JPH06184727A JP35690492A JP35690492A JPH06184727A JP H06184727 A JPH06184727 A JP H06184727A JP 35690492 A JP35690492 A JP 35690492A JP 35690492 A JP35690492 A JP 35690492A JP H06184727 A JPH06184727 A JP H06184727A
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- Prior art keywords
- steel
- hardening
- gas
- heated
- subjected
- Prior art date
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Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、鉄鋼製機械部品に優れ
た耐摩耗性、耐疲労性を付与し得る表面硬化法に関す
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface hardening method capable of imparting excellent wear resistance and fatigue resistance to steel machine parts.
【０００２】[0002]
【従来の技術およびその問題点】鉄鋼製機械部品の耐摩
耗性、耐疲労性向上を目的とした表面硬化法として、浸
炭窒化焼戻し、ガス窒化、タフトライド、ガス軟窒化、
高周波表面焼入れが多く実施されている。しかし、これ
らは目的を略同じにするものの、それぞれ特徴があっ
て、相互に代替できるものではなく、相互に補完し合う
ものである。例えば、浸炭窒化焼戻し、高周波表面焼入
れの場合、硬化原理がマルテンサイトを利用することに
あるため、得られる最高硬さは高々８００Ｈｖ程度で、
使用温度が２００℃を超えると、性能が極端に低下して
しまう。また、ガス窒化、タフトライド、ガス軟窒化
は、主として鉄あるいは合金元素の析出物を利用するの
で、窒素と親和力の強い合金元素を多く含む鋼では１０
００Ｈｖ以上の硬さになり、耐熱性がある。しかし、こ
れらの場合は、析出硬化の大きい低温度域、すなわち５
００〜６００℃で処理するので、概して窒素の侵入深さ
が小さく、浸炭窒化焼入れ焼戻し、高周波表面焼入れに
比べて硬化深さが小さいものである。2. Description of the Related Art As a surface hardening method for improving wear resistance and fatigue resistance of steel machine parts, carbonitriding tempering, gas nitriding, tuftride, gas nitrocarburizing,
Induction surface hardening is often used. However, although they have substantially the same purpose, they have their own characteristics and are not mutually replaceable, but they complement each other. For example, in the case of carbonitriding tempering and induction surface quenching, the hardening principle is to use martensite, so the maximum hardness that can be obtained is about 800 Hv at most.
If the operating temperature exceeds 200 ° C, the performance will be extremely reduced. Moreover, since gas nitriding, tufftride, and gas soft nitriding mainly utilize precipitates of iron or alloying elements, it is 10 in steel containing many alloying elements having a strong affinity with nitrogen.
It has a hardness of 00 Hv or more and is heat resistant. However, in these cases, a low temperature range where precipitation hardening is large, that is, 5
Since the treatment is performed at 00 to 600 ° C., the penetration depth of nitrogen is generally small, and the hardening depth is small as compared with carbonitriding quenching and tempering and induction surface quenching.
【０００３】本発明は、上記した如き従来の問題点を改
善し、従来の窒化法よりも硬化深さが大きく、従って耐
摩耗性及び耐疲労性に優れた鉄鋼性部品の表面硬化法を
提供することを目的とするものである。The present invention provides a surface hardening method for iron and steel parts which has improved the above-mentioned conventional problems and has a larger hardening depth than the conventional nitriding method, and therefore has excellent wear resistance and fatigue resistance. The purpose is to do.
【０００４】[0004]
【問題点を解決するための手段】本発明の表面硬化法
は、Ｎとの化学親和力の強い元素を含む鋼を素材とする
部品を、残部非酸化性ガスに１〜３０容量％のＮＨ3を
混合した雰囲気中で６００〜９００℃に加熱して浸窒さ
せ、室温まで急速冷却し、その後４００〜６００℃で析
出硬化処理するか、もしくは６００〜９００℃に加熱し
て窒化させた後、直ちに４００〜６００℃まで急冷し
て、ここで析出硬化させることを特徴とする。According to the surface hardening method of the present invention, a part made of steel containing an element having a strong chemical affinity with N is used as the balance of 1 to 30% by volume of NH 3 in a non-oxidizing gas. Is heated to 600 to 900 ° C. in a mixed atmosphere for nitrification, rapidly cooled to room temperature, and then precipitation hardened at 400 to 600 ° C. or heated to 600 to 900 ° C. for nitriding, It is characterized in that it is rapidly cooled to 400 to 600 ° C. and precipitation hardening is performed here.
【０００５】本発明は、合金元素の窒化物の析出を利用
するものであるから、Ｎとの化学親和力の強い元素、す
なわち、Ｍｎ，Ｃｒ，Ｍｏ，Ｖ，Ａｌ，Ｎｂ，Ｚｒ，Ｔ
ｉのいずれか１種又は２種以上を含む鉄鋼素材を用い
る。Since the present invention utilizes the precipitation of the alloy element nitride, it has an element having a strong chemical affinity with N, that is, Mn, Cr, Mo, V, Al, Nb, Zr, and T.
A steel material containing one or more of i is used.
【０００６】[0006]
【作用】このような本発明は硬化因子として鉄及び合金
元素の窒化物の析出を利用するものであり、その原理は
ガス窒化、タフトライド、ガス軟窒化と同じであるが、
窒素を従来の窒化法より高い６００℃以上という温度で
浸入させ、一旦急冷して窒素をできるだけ固溶状態に凍
結し、その後、４００〜６００℃の温度に保持して鉄及
び合金元素の炭窒化物を析出させるものであるため、窒
素を鉄鋼中に浸入させる処理と浸入した窒素を析出硬化
させる処理とが明確に分離されることによって、硬化深
さが従来の窒化法に比べて深くなる。The present invention utilizes precipitation of iron and alloying element nitrides as a hardening factor, and the principle thereof is the same as that of gas nitriding, tuftride, and gas soft nitriding.
Nitrogen is infiltrated at a temperature of 600 ° C. or higher, which is higher than that of the conventional nitriding method, and once quenched to freeze nitrogen in a solid solution state as much as possible, and thereafter, it is kept at a temperature of 400 to 600 ° C. to carbonitride iron and alloy elements. Since the substance is deposited, the process of infiltrating nitrogen into the steel and the process of precipitating and hardening the infiltrated nitrogen are clearly separated, so that the hardening depth becomes deeper than that of the conventional nitriding method.
【０００７】以下、本発明を詳細に説明する。本発明に
おいて、鋼材中に含有させるＮとの化学親和力の強い元
素、すなわち、Ｍｎ，Ｃｒ，Ｍｏ，Ｖ，Ａｌ，Ｎｂ，Ｚ
ｒ，Ｔｉのいずれか１種又は２種以上の量は、各元素と
Ｎとの化学親和力の強さ及びこれら析出物による硬化
代、さらには複合添加による相互作用の程度によるの
で、一概に必要量を決めることはできない。しかし、素
材の機械加工性、コスト等を勘案すると、これら元素の
必要量範囲は０．５〜２．５％Ｍｎ，０．５〜６％Ｃ
ｒ，０．１〜１％Ｍｏ，０．０５〜０．５％Ｖ，０．０
１〜１％Ａｌ，０．０２〜０．２％Ｎｂ，Ｚｒ，Ｔｉ程
度とする。The present invention will be described in detail below. In the present invention, elements having a strong chemical affinity with N contained in the steel material, that is, Mn, Cr, Mo, V, Al, Nb, Z.
The amount of any one or two or more of r and Ti depends on the strength of the chemical affinity between each element and N, the hardening margin due to these precipitates, and the degree of interaction due to the complex addition, and is therefore generally required. The amount cannot be determined. However, considering the machinability of the material, the cost, etc., the required amount range of these elements is 0.5 to 2.5% Mn, 0.5 to 6% C.
r, 0.1 to 1% Mo, 0.05 to 0.5% V, 0.0
It is about 1 to 1% Al, 0.02 to 0.2% Nb, Zr, and Ti.
【０００８】上記素材からなる機械部品を１〜３０容量
％ＮＨ3＋非酸化性ガス雰囲気中で加熱して浸窒を行
う。アンモニアを含む高温ガスは、鋼に対して非常に高
いＮポテンシャルを有するので、鋼の浸窒は１容量％Ｎ
Ｈ3でも起こるが、３０容量％ＮＨ3を超えると窒素が入
りすぎて鋼中にブローホールができるようになる。アン
モニアを希釈するガスとしては鋼に対し非酸化性ガスで
あれば、いかなる種類のガスでもよく、当然混合ガスで
もよい。一般的には、窒素ガスがよい。また、浸炭で使
用するＲＸガスでもよいが、この場合は浸窒と同時に浸
炭も起こることを念頭に置かなければならない。Nitrogen is carried out by heating a mechanical part made of the above material in an atmosphere of 1 to 30% by volume NH 3 + non-oxidizing gas. Since hot gas containing ammonia has a very high N potential for steel, the nitriding of steel is 1% by volume N
Although it also occurs in H 3, if it exceeds 30 vol% NH 3 , nitrogen will enter too much and blow holes will be formed in the steel. As a gas for diluting ammonia, any kind of gas may be used as long as it is a non-oxidizing gas for steel, and naturally, a mixed gas may be used. Generally, nitrogen gas is preferred. Further, RX gas used for carburizing may be used, but in this case, it must be kept in mind that carburizing occurs simultaneously with carburizing.
【０００９】上記雰囲気中での加熱温度については、１
容量％ＮＨ3の５００℃雰囲気中でも浸窒は起こるが、
その程度と窒素の到達深さが問題となる。アンモニア濃
度及び温度の高い雰囲気ほど、また加熱時間が長いほ
ど、浸窒量も多く、窒素の到達深さも大きくなる。一
方、浸入した窒素全部が直ちに化合物を形成するような
温度域は避けなければならず、本発明においては、これ
らの点から処理温度を６００〜９００℃の温度範囲とす
る。このような温度域は、素材の合金成分及び量によっ
て状態図から推定できるものである。本発明の適正なア
ンモニア濃度、処理温度及び時間は、被処理部品の素材
の合金成分、量及び硬化度の必要特性から、最も経済的
な組合せを選択する。The heating temperature in the above atmosphere is 1
Nitrogenation occurs even in a 500 ° C atmosphere with a volume% NH 3 , but
The extent and depth of nitrogen reach are important issues. The higher the concentration of ammonia and the temperature, and the longer the heating time, the greater the amount of nitrification and the greater the reaching depth of nitrogen. On the other hand, it is necessary to avoid a temperature range in which all the invaded nitrogen immediately forms a compound, and in the present invention, the treatment temperature is set to a temperature range of 600 to 900 ° C. from these points. Such temperature range can be estimated from the phase diagram depending on the alloy composition and amount of the material. The proper ammonia concentration, treatment temperature and time of the present invention are selected in the most economical combination from the required characteristics of the alloy component, the amount and the degree of hardening of the material of the component to be treated.
【００１０】このようにして浸入させた固溶窒素を有効
に利用するために、急冷して固溶状態をできるだけ保持
し、硬化度の高い温度域、すなわち、４００〜６００℃
で析出させる。具体的には、（１）浸窒処理温度から室
温まで一旦急冷し、改めて４００〜６００℃に加熱、保
持する。（２）浸窒処理温度から４００〜６００℃まで
急冷して、保定する。これらの析出温度及び保持時間は
やはり被処理部品の素材の合金成分、量及びその必要特
性から決定されるものである。また、急冷の目的が窒素
の析出抑制することのあるので、その急冷度は鋼の焼入
れ処理の場合ほど厳密なものではない。被処理部品の肉
厚、質量にもよるが、放冷でよい場合もある。In order to effectively utilize the solid solution nitrogen thus infiltrated, the solid solution state is maintained by quenching as much as possible, and the temperature range where the degree of curing is high, that is, 400 to 600 ° C.
To precipitate. Specifically, (1) the temperature of the nitriding treatment is once rapidly cooled to room temperature, and then again heated to 400 to 600 ° C. and held. (2) Rapidly cool from the nitriding temperature to 400 to 600 ° C. and hold. These precipitation temperature and holding time are also determined by the alloy composition, the amount, and the required characteristics of the raw material of the component to be treated. Further, since the purpose of quenching is to suppress precipitation of nitrogen, the degree of quenching is not as strict as in the case of quenching of steel. Depending on the thickness and mass of the parts to be processed, cooling may be sufficient in some cases.
【００１１】[0011]
【発明の効果】このような本発明によれば、従来の窒化
部品のよい特性を維持しつつ、硬化深さが小さいあるい
は処理時間が長いといった従来法の欠点が解消され、耐
摩耗性及び耐疲労性が優れた表面処理方法が得られる。According to the present invention as described above, while maintaining the good characteristics of the conventional nitrided parts, the drawbacks of the conventional method such as a small hardening depth or a long processing time are eliminated, and the wear resistance and the wear resistance are improved. A surface treatment method with excellent fatigue resistance can be obtained.
【００１２】[0012]
【実施例１】ＪＩＳ規格のＳＫＤ６１の約２０ｍｍφ×
１００ｍｍの調質していない棒鋼を１０％ＮＨ3＋Ｎ2に
調合したガス中で、８５０℃で２時間加熱し、その後９
０℃の焼入れ油中に急冷した。これを５５０℃で６０分
の析出硬化処理をした。このように処理したものの中央
部を輪切りにして、１０ｍｍ厚みの試験片を採取し、切
断面を研磨して、表層のビッカース硬さ分布を測定し
た。この結果を図１に示す。なお、比較のために、同種
の調質棒鋼を従来のガス窒化法、すなわち、５４０℃で
３５時間、アンモニアの解離度３０〜６０％の条件で窒
化し、表層のビッカース硬さ分布を測定した。この結果
も図１に併記した。図１より、処理時間が１／１０以下
であるのに、表層のビッカース硬さ分布はほぼ同じであ
り、本発明の効果が明らかとなった。[Example 1] JIS standard SKD61 of about 20 mmφ x
A 100 mm unbarred steel bar was heated at 850 ° C. for 2 hours in a gas prepared by mixing 10% NH 3 + N 2 and then 9
Quenched in 0 ° C. quenching oil. This was subjected to a precipitation hardening treatment at 550 ° C. for 60 minutes. The center portion of the thus treated product was cut into slices to obtain a 10 mm-thick test piece, the cut surface was polished, and the Vickers hardness distribution of the surface layer was measured. The result is shown in FIG. For comparison, a tempered steel bar of the same kind was nitrided by a conventional gas nitriding method, that is, at 540 ° C. for 35 hours under the condition that the dissociation degree of ammonia was 30 to 60%, and the Vickers hardness distribution of the surface layer was measured. . The results are also shown in FIG. From FIG. 1, although the processing time was 1/10 or less, the Vickers hardness distribution of the surface layer was almost the same, and the effect of the present invention was clarified.
【００１３】[0013]
【実施例２】ＪＩＳ規格のＳＣＭ４３５の約２０ｍｍφ
×１００ｍｍの調質していない棒鋼を５％ＮＨ3＋Ｎ2に
調合したガス中で、８００℃で２時間加熱し、加熱終了
後直ちに５２０℃のソルトバスに移し、６０分間の析出
硬化処理をした。このように処理したものの中央部を輪
切りにして、１０ｍｍ厚みの試験片を採取し、切断面を
研磨して、表層のビッカース硬さ分布を測定した。この
結果を図２に示す。なお、比較のために、同種の調質棒
鋼を従来のガス軟窒化法、すなわち、５０％ＮＨ3＋Ｒ
Ｘガス中、５７０℃で３時間の条件で軟窒化し、表層の
ビッカース硬さ分布を測定した。この結果も図２に併記
した。図２より、処理時間は同じであるが、硬さも硬化
深さも大きくなり、本発明の効果が明らかとなった。[Example 2] About 20 mmφ of JIS SCM435
× 100 mm unheated steel bar was heated in a gas mixed with 5% NH 3 + N 2 at 800 ° C. for 2 hours, and immediately after the heating was completed, it was transferred to a 520 ° C. salt bath for 60 minutes for precipitation hardening treatment. did. The center portion of the thus treated product was cut into slices to obtain a 10 mm-thick test piece, the cut surface was polished, and the Vickers hardness distribution of the surface layer was measured. The result is shown in FIG. For comparison, a tempered steel bar of the same kind is produced by the conventional gas soft nitriding method, that is, 50% NH 3 + R.
It was soft nitrided in X gas at 570 ° C. for 3 hours, and the Vickers hardness distribution of the surface layer was measured. The results are also shown in FIG. From FIG. 2, although the treatment time was the same, the hardness and the curing depth were increased, and the effect of the present invention was clarified.
【図１】本発明の実施例１におけるビッカース硬さ分布
図である。FIG. 1 is a Vickers hardness distribution diagram in Example 1 of the present invention.
【図２】本発明の実施例２におけるビッカース硬さ分布
図である。FIG. 2 is a Vickers hardness distribution diagram in Example 2 of the present invention.
Claims (3)
素材とする部品を、残部非酸化性ガスに１〜３０容量％
のＮＨ3を混合した雰囲気中で６００〜９００℃に加熱
して浸窒させ、室温まで急速冷却し、その後４００〜６
００℃で析出硬化処理することを特徴とする鉄鋼製部品
の表面硬化法。1. A component made of steel containing an element having a strong chemical affinity with N as a raw material, the balance being 1 to 30% by volume in a non-oxidizing gas.
In an atmosphere mixed with NH 3 of 600 to 900 ° C. for nitriding, rapid cooling to room temperature, and then 400 to 6
A surface hardening method for steel parts, characterized by performing a precipitation hardening treatment at 00 ° C.
素材とする部品を、残部非酸化性ガスに１〜３０容量％
のＮＨ3を混合した雰囲気中で６００〜９００℃に加熱
して浸窒させた後、直ちに４００〜６００℃まで急冷し
て、ここで析出硬化させることを特徴とする鉄鋼製部品
の表面硬化法。2. A component made of steel containing an element having a strong chemical affinity with N as a raw material, the residual non-oxidizing gas being 1 to 30% by volume.
Surface hardening method for steel parts, characterized by heating to 600 to 900 ° C. in a mixed atmosphere of NH 3 to cause nitrification, and then immediately quenching to 400 to 600 ° C., where precipitation hardening is performed. .
Ｃｒ，Ｍｏ，Ｖ，Ａｌ，Ｎｂ，Ｚｒ，Ｔｉのいずれか１
種又は２種以上である請求項１又は２記載の鉄鋼製部品
の表面硬化法。3. An element having a strong chemical affinity with N is Mn,
Any one of Cr, Mo, V, Al, Nb, Zr, Ti
The method for hardening the surface of a steel component according to claim 1 or 2, wherein the surface hardening method is one or more kinds.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP35690492A JPH06184727A (en) | 1992-12-22 | 1992-12-22 | Method for hardening surface of part made of steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP35690492A JPH06184727A (en) | 1992-12-22 | 1992-12-22 | Method for hardening surface of part made of steel |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH06184727A true JPH06184727A (en) | 1994-07-05 |
Family
ID=18451348
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP35690492A Pending JPH06184727A (en) | 1992-12-22 | 1992-12-22 | Method for hardening surface of part made of steel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH06184727A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011241470A (en) * | 2010-05-21 | 2011-12-01 | Jfe Steel Corp | Ferrous material and method of manufacturing the same |
| JP2012219317A (en) * | 2011-04-07 | 2012-11-12 | Jfe Steel Corp | Iron-based material and method for producing the same |
| JP2013044037A (en) * | 2011-08-25 | 2013-03-04 | Jfe Steel Corp | Iron-based material and manufacturing method therefor |
| JP2013044036A (en) * | 2011-08-25 | 2013-03-04 | Jfe Steel Corp | Method for producing ferrous material |
| WO2014104085A1 (en) * | 2012-12-26 | 2014-07-03 | 学校法人名城大学 | Surface-hardened metal material and surface-hardening treatment method therefor |
-
1992
- 1992-12-22 JP JP35690492A patent/JPH06184727A/en active Pending
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011241470A (en) * | 2010-05-21 | 2011-12-01 | Jfe Steel Corp | Ferrous material and method of manufacturing the same |
| JP2012219317A (en) * | 2011-04-07 | 2012-11-12 | Jfe Steel Corp | Iron-based material and method for producing the same |
| JP2013044037A (en) * | 2011-08-25 | 2013-03-04 | Jfe Steel Corp | Iron-based material and manufacturing method therefor |
| JP2013044036A (en) * | 2011-08-25 | 2013-03-04 | Jfe Steel Corp | Method for producing ferrous material |
| WO2014104085A1 (en) * | 2012-12-26 | 2014-07-03 | 学校法人名城大学 | Surface-hardened metal material and surface-hardening treatment method therefor |
| JPWO2014104085A1 (en) * | 2012-12-26 | 2017-01-12 | 学校法人 名城大学 | Metal material in which surface layer is cured and surface layer curing method |
| US9777363B2 (en) | 2012-12-26 | 2017-10-03 | Meijo University | Surface layer hardened metal material and surface layer hardening method |
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