JPH0717995B2 - Manufacturing method of ferrous sintered alloy members with excellent wear resistance - Google Patents
Manufacturing method of ferrous sintered alloy members with excellent wear resistanceInfo
- Publication number
- JPH0717995B2 JPH0717995B2 JP18304386A JP18304386A JPH0717995B2 JP H0717995 B2 JPH0717995 B2 JP H0717995B2 JP 18304386 A JP18304386 A JP 18304386A JP 18304386 A JP18304386 A JP 18304386A JP H0717995 B2 JPH0717995 B2 JP H0717995B2
- Authority
- JP
- Japan
- Prior art keywords
- iron
- sintered alloy
- based sintered
- weight
- carbide
- 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
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Description
【発明の詳細な説明】 （産業上の利用分野） 本発明は、エンジンの動弁系の構成部品等を形成するに
用いられる耐摩耗性に優れた鉄系焼結合金部材の製造法
に関する。Description: TECHNICAL FIELD The present invention relates to a method for manufacturing an iron-based sintered alloy member having excellent wear resistance, which is used for forming components of a valve train of an engine.
（従来の技術） エンジンにおける動弁系の構成部材の如くの摺動部品を
形成するにあたって用いられる金属材料は、高温下にお
ける強度及び耐摩耗性に優れることが要求される。高温
下における強度及び耐摩耗性に優れた金属材料として
は、従来、例えば、特開昭59−83704号公報にも記載さ
れている如く、炭素とクロムあるいはモリブデン等の炭
素との親和性が大である金属元素とが含まれた合金粉末
を焼結することにより、内部にクロムあるいはモリブデ
ン等の複合炭化物が形成された鉄系焼結合金等が知られ
ている。斯かる鉄系焼結合金は、それに含まれるクロム
あるいはモリブデン等の複合炭化物が主として内部マト
リックスの硬度の向上に寄与するものとなっており、従
って、その内部の硬度が大なるものとされるが、例え
ば、エンジンの動弁系におけるロッカーアームの摺動面
部を形成するに用いられるに際しては、内部の硬度が大
であることに加えて、その表面部分の硬度が向上せしめ
られることが望まれる。(Prior Art) A metal material used for forming a sliding part such as a component of a valve train in an engine is required to have excellent strength and wear resistance at high temperatures. As a metal material excellent in strength and wear resistance at high temperatures, conventionally, for example, as described in JP-A-59-83704, carbon has a high affinity with carbon such as chromium or molybdenum. There is known an iron-based sintered alloy or the like in which a compound carbide such as chromium or molybdenum is formed inside by sintering an alloy powder containing a metal element such as. In such an iron-based sintered alloy, the compound carbide such as chromium or molybdenum contained in the iron-based sintered alloy mainly contributes to the improvement of the hardness of the internal matrix, and therefore, the internal hardness thereof is considered to be large. For example, when it is used for forming a sliding surface portion of a rocker arm in a valve train of an engine, it is desired that the hardness of the surface portion be improved in addition to the large internal hardness.
一般に、金属体における表面部分の硬度を向上させるに
は、その金属体の表面部分に硬化層を形成することが行
われるが、金属体の表面部分に硬化層を形成するにあた
っては、アルミニウムあるいはクロムを含有する金属体
に対して、アンモニア・ガス流中において500〜525℃程
度の温度で数10時間の加熱処理を施し、それにより、窒
素を金属体の表面から内部へ拡散させて、金属体の表面
部分に、0.2〜0.3mm程度の厚みのアルミニウムあるいは
クロムの窒化物層からなる硬化層を形成するようになす
ガス窒化法や、金属体の表面に溶融状態にある金属粒子
を吹き付けることにより、その金属体の表面部分に硬化
層を形成する金属溶射法が知られている。Generally, in order to improve the hardness of the surface portion of the metal body, a hardened layer is formed on the surface portion of the metal body. When forming the hardened layer on the surface portion of the metal body, aluminum or chromium is used. The metal body containing is subjected to heat treatment in an ammonia gas flow at a temperature of about 500 to 525 ° C. for several tens of hours, whereby nitrogen is diffused from the surface of the metal body to the inside, and By a gas nitriding method that forms a hardened layer consisting of a nitride layer of aluminum or chromium with a thickness of about 0.2 to 0.3 mm on the surface part of, or by spraying molten metal particles on the surface of the metal body A metal spraying method is known in which a hardened layer is formed on the surface of the metal body.
従って、上述の鉄系焼結合金についても、それにガス窒
化法あるいは金属溶射法を適用して表面部分に硬化層を
形成することにより、その表面部分の硬度の向上を図る
ことができる。Therefore, also for the above-mentioned iron-based sintered alloy, the hardness of the surface portion can be improved by applying the gas nitriding method or the metal spraying method to form the hardened layer on the surface portion.
（発明が解決しようとする問題点） しかしながら、前述の鉄系焼結合金の表面部分の硬度を
向上させるべく、その表面部分にガス窒化法によって硬
化層が形成されるようになされる場合には、鉄系焼結合
金の加熱処理に数10時間が要されることになって、生産
効率が著しく低いものとなってしまうという問題があ
り、また、鉄系焼結合金の表面部に金属溶射法によって
硬化層が形成されるようになされる場合には、鉄系焼結
合金の表面に溶射すべき金属を溶融させる工程や、溶融
された金属を微粒化して鉄系焼結合金の表面に吹き付け
る工程等が伴われ、そのために比較的大掛りな設備が必
要とされて、鉄系焼結合金の表面部分における硬化層の
形成に要するコストが著しく嵩んでしまうという問題が
ある。(Problems to be Solved by the Invention) However, in order to improve the hardness of the surface portion of the above-mentioned iron-based sintered alloy, when a hardened layer is formed on the surface portion by the gas nitriding method, However, there is a problem that the heat treatment of the iron-based sintered alloy requires several tens of hours and the production efficiency becomes extremely low. Moreover, the surface of the iron-based sintered alloy has a problem of metal spraying. When a hardened layer is formed by the method, the step of melting the metal to be sprayed on the surface of the iron-based sintered alloy, or atomizing the melted metal to the surface of the iron-based sintered alloy There is a problem that the step of spraying is involved, which requires a relatively large-scale facility, which significantly increases the cost required for forming the hardened layer on the surface portion of the iron-based sintered alloy.
斯かる点に鑑み、本発明は、内部硬度が大であることに
加えて、表面部分に適正な硬化層が形成されてその表面
部分の硬度が向上せしめられた鉄系焼結合金部材を、製
造コストの低減を図ることができるもとで、比較的高い
生産効率をもって得ることができる、耐摩耗性に優れた
鉄系焼結合金部材の製造法を提供することを目的とす
る。In view of such a point, the present invention, in addition to having a large internal hardness, an iron-based sintered alloy member in which an appropriate hardened layer is formed on the surface portion and the hardness of the surface portion is improved, An object of the present invention is to provide a method for producing an iron-based sintered alloy member having excellent wear resistance, which can be obtained with relatively high production efficiency while being able to reduce the production cost.
（問題点を解決するための手段） 上述の目的を達成すべく、本発明に係る耐摩耗性に優れ
た鉄系焼結合金部材の製造法は、1.2〜2.5重量％の炭素
と、7.0〜9.5重量％のクロム及び2.0〜5.5重量％のモリ
ブデンのうちの少なくとも１種とが含まれる鉄系焼結合
金を用意し、その鉄系焼結合金に対して、炭素濃度が0.
7〜1.2の雰囲気中において900〜950℃の温度で浸炭処理
を施し、その表面にクロムの炭化物及びモリブデンの炭
化物のうちの少なくとも一方から成る炭化物層を形成す
るものとされる。(Means for Solving Problems) In order to achieve the above-mentioned object, a method for producing an iron-based sintered alloy member having excellent wear resistance according to the present invention is 1.2 to 2.5 wt% carbon and 7.0 to An iron-based sintered alloy containing 9.5 wt% chromium and at least one of 2.0 to 5.5 wt% molybdenum is prepared, and the carbon concentration of the iron-based sintered alloy is 0.
Carburizing is performed at a temperature of 900 to 950 ° C. in an atmosphere of 7 to 1.2 to form a carbide layer made of at least one of chromium carbide and molybdenum carbide on the surface.
（作用） このような、本発明に係る耐摩耗性に優れた鉄系焼結合
金部材の製造法によれば、鉄系焼結合金に含まれるクロ
ム及びモリブデンのうちの少なくとも１種が、鉄系焼結
合金に対する浸炭素処理が行われる際に、浸炭処理にお
ける雰囲気中に含まれて鉄系焼結合金の表面からその内
部に拡散するものとなる炭素と結合し、その結果、鉄系
焼結合金の表面部分にクロムの炭化物及びモリブデンの
炭化物うちの少なくとも一方から成る耐摩耗性に優れた
炭化物層が、硬化層として形成されることになる。(Operation) According to the method for manufacturing an iron-based sintered alloy member having excellent wear resistance according to the present invention, at least one of chromium and molybdenum contained in the iron-based sintered alloy is iron. When the carburizing treatment is performed on the system-based sintered alloy, it is combined with the carbon contained in the atmosphere during the carburizing process and diffused from the surface of the ferrous-based sintered alloy to the inside thereof. A carbide layer having at least one of chromium carbide and molybdenum carbide having excellent wear resistance is formed as a hardened layer on the surface portion of the bond gold.
そして、鉄系焼結合金に対する浸炭処理に要する時間
は、例えば、ガス窒化法に従って鉄系焼結合金が加熱処
理されるに要される時間に比して大幅に短縮されたもの
となされ、それにより、比較的高い生産効率が得られ
る。また、鉄系焼結合金の表面部分における硬化層の形
成に要するコストは、金属溶射法に従って鉄系焼結合金
の表面に溶融金属の微粒子が吹き付けられる場合に比し
て、著しく低減し得るものとなる。The time required for carburizing the iron-based sintered alloy is, for example, significantly shorter than the time required for heat-treating the iron-based sintered alloy according to the gas nitriding method. As a result, relatively high production efficiency can be obtained. In addition, the cost required for forming a hardened layer on the surface of the iron-based sintered alloy can be significantly reduced as compared with the case where fine particles of molten metal are sprayed on the surface of the iron-based sintered alloy according to the metal spraying method. Becomes
（実施例） 以下に、本発明に係る耐摩耗性に優れた鉄系焼結合金部
材の製造法の一例によって、鉄系焼結合金部材を得る場
合について述べる。(Example) Hereinafter, the case of obtaining an iron-based sintered alloy member by an example of the method for producing an iron-based sintered alloy member having excellent wear resistance according to the present invention will be described.
先ず、炭素（Ｃ）が1.2〜2.5重量％，クロム（Cr）が7.
0〜9.5重量％，モリブデン（Mo）が2.0〜5.5重量％，燐
（Ｐ）が0.7〜1.5重量％、及び、鉄（Fe）が残部の主成
分となる比率をもって各元素が配合された鉄系焼結合金
を得る。First, 1.2 to 2.5% by weight of carbon (C) and 7.
Iron mixed with 0 to 9.5% by weight, molybdenum (Mo) at 2.0 to 5.5% by weight, phosphorus (P) at 0.7 to 1.5% by weight, and iron (Fe) as the main component of the balance. Obtain a system sintered alloy.
斯かる成分組成の鉄系合金粉末は、具体的には、例え
ば、Crが12重量％含有され、マンガン（Mn），珪素（S
i）,P及び硫黄（Ｓ）が、夫々、１重量％,1重量％,0.04
3重量％及び0.03重量％を越えない範囲で含有されると
ともに、Feが残部となる組成を有した第１の合金粉末
（SUS410）と、Crが４重量％,Moが９重量％,Pが2.4重量
％,Cが4.2重量％、及び、Feが残部となる組成を有した
第２の合金粉末とを、夫々の粒度を150メッシュ以下と
した状態で、約7:3,約6:4,約5:5,約4:6等の割合で混合
することにより得られる。このようにして、第１及び第
２の合金粉末を約7:3,約6:4,約5:5,約4:6の割合で混合
することにより得られる４種の鉄系合金粉末（以下、試
料T1，T2，T3及びT4という）は、下記の表−１に示され
る如くの成分組成を有するものとなる。Specifically, the iron-based alloy powder having such a component composition contains, for example, 12% by weight of Cr, and contains manganese (Mn), silicon (S
i), P and sulfur (S) are 1% by weight, 1% by weight and 0.04%, respectively.
The first alloy powder (SUS410) containing 3% by weight and 0.03% by weight and having the composition of Fe as the balance, 4% by weight of Cr, 9% by weight of Mo and P 2.4% by weight, 4.2% by weight of C, and a second alloy powder having a composition in which Fe is the balance, with a particle size of 150 mesh or less, about 7: 3, about 6: 4 , About 5: 5, about 4: 6 and the like. In this manner, four kinds of iron-based alloy powders ((4) obtained by mixing the first and second alloy powders in a ratio of about 7: 3, about 6: 4, about 5: 5, about 4: 6 ( Hereinafter, the samples T 1 , T 2 , T 3 and T 4 ) will have the composition as shown in Table 1 below.
次に、上述の試料T1〜T4の如くの鉄系合金粉末に、バイ
ンダとしてパラフィン1.5重量％を添加して混合した
後、5ton/cm2の圧力をかけて圧縮し、例えば10mm×30mm
×50mmの直方体状の圧粉体を形成する。 Next, after adding 1.5 wt% of paraffin as a binder to the iron-based alloy powder such as the above-mentioned samples T 1 to T 4 and mixing them, the mixture was compressed by applying a pressure of 5 ton / cm 2 , for example, 10 mm × 30 mm.
A rectangular parallelepiped green compact having a size of 50 mm is formed.
このようにして形成された鉄系合金粉末から成る圧粉体
を、水素ガス（H2）雰囲気中において600℃まで昇温加
熱した後、その状態を30分間保持して、予備焼結を行
う。さらに、得られた予備焼結体を、真空炉中で、10℃
/minの加熱勾配をもって昇温加熱していき、1060〜1100
℃の焼結温度をもっての加熱焼結状態を20分間保持し、
その後930℃まで降温して、鉄系焼結合金を得る。The green compact made of iron-based alloy powder thus formed is heated to 600 ° C. in a hydrogen gas (H 2 ) atmosphere, and then held in that state for 30 minutes for pre-sintering. . Furthermore, the obtained pre-sintered body is placed in a vacuum furnace at 10 ° C.
1060 ~ 1100
Hold the heating and sintering state at a sintering temperature of ℃ for 20 minutes,
Then, the temperature is lowered to 930 ° C. to obtain an iron-based sintered alloy.
続いて、得られた鉄系焼結合金に対し、炭素濃度が0.7
〜1.2％とされた雰囲気中において930℃の温度のもとに
40分間の浸炭処理を施す。Then, the carbon concentration of the obtained iron-based sintered alloy was 0.7
Under the temperature of 930 ℃ in an atmosphere of ~ 1.2%
Carburize for 40 minutes.
そして、浸炭処理が施された鉄系焼結合金を900℃まで
降温して、窒素ガス（N2）による焼入れ処理を施し、そ
の後、560℃に降温した状態で100分間保持して焼戻し処
理を行う。Then, the carburized iron-based sintered alloy is cooled to 900 ° C, quenched by nitrogen gas (N 2 ), and then kept at 560 ° C for 100 minutes to be tempered. To do.
以上の工程を経ることにより、その内部の硬度が大であ
り、かつ、その表面部分に、Crの炭化物及びMoの炭化物
のうちの少なくとも一方から成る炭化物層が硬化層とし
て形成された、耐摩耗性に優れた鉄系焼結合金部材が得
られる。Through the above steps, the hardness of the inside is large, and a carbide layer made of at least one of a carbide of Cr and a carbide of Mo is formed on its surface portion as a hardened layer, and wear resistance An iron-based sintered alloy member having excellent properties is obtained.
例えば、上述の試料T1〜T4の夫々により10mm×30mm×50
mmの直方体状の圧粉体が形成され、それらに基づいて得
られた鉄系焼結合金部材について、各々の表面部分に、
厚みが５〜15μ程度であり、硬度がHv＝1098〜1206であ
る炭化物層が形成されたことが確認された。斯かる炭化
物層は、その硬度が、各鉄系焼結合金部材の内部におけ
るマトリックス中に含まれる炭化物の硬度（Hv＝1064〜
1246）と同程度のものとなる。また、鉄系焼結合金部材
の内部におけるマトリックスの硬度は、表面部分の近傍
における値（Hv＝519〜606）と内部における値（Hv＝50
3〜606）との差が極めて小であることが確認された。こ
れは、鉄系焼結合金のオーステナイト域におけるＣが、
飽和状態とされて安定した状態におかれ、そのため、浸
炭処理に際して雰囲気中に含まれるＣの影響を受けにく
いものとされるからと考えられる。For example, 10 mm × 30 mm × 50 for each of the samples T 1 to T 4 described above.
mm rectangular parallelepiped green compact is formed, and for each iron-based sintered alloy member obtained based on them, on each surface portion,
It was confirmed that a carbide layer having a thickness of about 5 to 15 μm and a hardness of Hv = 1098 to 1206 was formed. The hardness of such a carbide layer is such that the hardness of the carbide contained in the matrix inside each iron-based sintered alloy member (Hv = 1064 to
1246). The hardness of the matrix inside the iron-based sintered alloy member is a value near the surface (Hv = 519 to 606) and a value inside (Hv = 50).
It was confirmed that the difference from the above was extremely small. This is because the C in the austenite region of the iron-based sintered alloy is
It is considered that the saturated state is kept in a stable state, and therefore it is unlikely to be affected by C contained in the atmosphere during the carburizing process.
明細書に付随する図は、試料T3に基づいて得られた圧粉
体を、予備焼結した後、真空炉中において1080℃の焼結
温度で20分間焼結し、炭素濃度が0.9％とされた雰囲気
中において930℃の温度のもとで40分間の浸炭処理を施
して、900℃の温度のもとに30分間のN2による焼入れを
行った後、560℃に降温した状態で100分間の焼戻し処理
を行って得た鉄系焼結合金部材について、その表面部分
の金属組織を示す、400倍に拡大された顕微鏡写真であ
る。この写真中において、横方向に帯状に連なる白色部
分が炭化物層であり、その硬度は、Hv＝≒1157であっ
た。また、この炭化物層の内部側（写真において下方）
に位置する黒色部分がマトリックスを構成する部分で、
そのマトリックスの硬度は、炭化物層の近傍及び内部に
おいて、夫々、Hv≒555及びHv≒571であった。さらに、
各マトリックスの内部に点在する白色部分は、鉄系合金
粉末に含まれたＣとCr,Mo及びFe等とが結合して形成さ
れた炭化物で、その硬度は、Hv≒1172であった。The figure accompanying the specification shows that the green compact obtained based on the sample T 3 was pre-sintered and then sintered in a vacuum furnace at a sintering temperature of 1080 ° C. for 20 minutes to obtain a carbon concentration of 0.9%. In the atmosphere described above, carburize for 40 minutes at a temperature of 930 ℃, quench with N 2 for 30 minutes at a temperature of 900 ℃, and then lower the temperature to 560 ℃. FIG. 3 is a micrograph magnified 400 times showing the metal structure of the surface of an iron-based sintered alloy member obtained by performing a tempering treatment for 100 minutes. In this photograph, the white portion that is continuous in a strip shape in the lateral direction is the carbide layer, and the hardness thereof is Hv = ≈1157. Also, the inside of this carbide layer (below in the photo)
The black part located at is the part that constitutes the matrix,
The hardness of the matrix was Hv≅555 and Hv≅571 near and inside the carbide layer, respectively. further,
The white portion scattered inside each matrix is a carbide formed by combining C contained in the iron-based alloy powder with Cr, Mo, Fe, etc., and its hardness was Hv≈1172.
上述の如くの本発明に係る耐摩耗性に優れた鉄系焼結合
金部材の製造法の一例において、圧粉体の形成に供され
る鉄系合金粉末が、Ｃを1.2〜2.5重量％、Crを7.0〜9.5
重量％、Moを2.0〜5.5重量％、Ｐを0.7〜1.5重量％含有
するものとされるのは、以下の理由による。In one example of the method for producing an iron-based sintered alloy member having excellent wear resistance according to the present invention as described above, the iron-based alloy powder used for forming the green compact has 1.2 to 2.5% by weight of C, Cr 7.0-9.5
The reason why the content of Mo, 2.0 to 5.5% by weight, and P of 0.7 to 1.5% by weight is included is as follows.
先ず、Ｃは、鉄系焼結合金のマトリックス中に固溶して
マトリックスの強化に寄与するとともに、Fe,Mo及びＰ
等の元素と反応して低融点の３元共晶を形成するものと
なる液相を発生させて、鉄系焼結合金の緻密化に寄与す
るものとなる。また、Cr,Mo及びFeと結合して炭化物を
形成する。このような事柄を踏まえてＣの含有量を規定
する実験を行った結果、Ｃの含有量が1.2重量％未満で
は、液相量が不足することになり、多数の気孔が生じ
て、鉄系焼結合金部材の硬度が充分に得られず、また、
浸炭処理時においてＣが鉄系焼結合金のマトリックス中
に拡散するために、鉄系焼結合金部材の表面部に安定し
た炭化物層が生成されないことが確認された。また、Ｃ
の含有量が2.5重量％を越える場合には、鉄系焼結合金
中においてＣが過飽和の状態におかれるので、鉄系焼結
合金に対して浸炭処理が施されても浸炭雰囲気中のＣが
鉄系焼結合金の表面部に充分に浸入せず、適正な炭化物
層が生成されないという問題、さらには、焼結時におけ
る液相量が過多となって組織が粗大化してしまう問題が
生じることが確認された。従って、Ｃの含有量は、1.2
〜2.5重量％の範囲とされるのである。First, C contributes to strengthening the matrix by forming a solid solution in the matrix of an iron-based sintered alloy, and at the same time Fe, Mo and P
And the like to generate a liquid phase that forms a low melting point ternary eutectic and contributes to the densification of the iron-based sintered alloy. It also combines with Cr, Mo and Fe to form carbides. As a result of conducting an experiment to regulate the content of C in consideration of such matters, when the content of C is less than 1.2% by weight, the liquid phase amount becomes insufficient, and a large number of pores are generated, and the iron-based material is generated. The hardness of the sintered alloy member is not sufficiently obtained, and
It was confirmed that a stable carbide layer was not formed on the surface of the iron-based sintered alloy member because C diffused into the matrix of the iron-based sintered alloy during the carburizing treatment. Also, C
When the content of C exceeds 2.5% by weight, C is placed in a supersaturated state in the iron-based sintered alloy, so even if the iron-based sintered alloy is carburized, C in the carburizing atmosphere Does not sufficiently penetrate into the surface of the iron-based sintered alloy, and an appropriate carbide layer is not formed. Furthermore, there is a problem that the amount of liquid phase during sintering becomes excessive and the structure becomes coarse. It was confirmed. Therefore, the content of C is 1.2
The range is up to 2.5% by weight.
Cr及びMoは、鉄系焼結合金のマトリックス中に固溶して
マトリックスの強化に寄与するとともに、Ｃと結合して
炭化物を形成することにより、鉄系焼結合金の耐摩耗性
の向上に寄与するものとなる。また、浸炭処理によって
鉄系焼結合金の内部に拡散するＣと優先的に反応して、
鉄系焼結合金部材の表面部分にそれらの炭化物層から成
る硬化層を積極的に形成す。このため、このような事柄
を踏まえて、Cr及びMoの含有量を規定する実験を行った
結果、Crの含有量が7.0重量％未満である場合、あるい
は、Moの含有量が2.0重量％未満である場合には、鉄系
焼結合金部材の表面に炭化部層が充分に形成されない虞
があり、また、Crの含有量が9.5重量％を越える場合、
あるいは、Moの含有量が5.5重量％を越える場合には、C
r及びMoが浸炭処理によって鉄系焼結合金の内部に拡散
するＣと反応することによりマトリクス中に形成される
炭化物が粗大化して、鉄系焼結合金部材の靱性が損なわ
れることが認められた。従って、Cr及びMoの含有量は、
夫々、7.0〜9.5重量％、及び、2.0〜5.5重量％の範囲と
される。Cr and Mo form a solid solution in the matrix of the iron-based sintered alloy to contribute to the strengthening of the matrix, and combine with C to form a carbide to improve the wear resistance of the iron-based sintered alloy. Will contribute. In addition, the carburizing treatment preferentially reacts with C diffused inside the iron-based sintered alloy,
A hardened layer composed of these carbide layers is positively formed on the surface portion of the iron-based sintered alloy member. Therefore, based on such matters, as a result of an experiment that regulates the contents of Cr and Mo, when the content of Cr is less than 7.0% by weight, or when the content of Mo is less than 2.0% by weight. When it is, there is a possibility that the carbonized portion layer is not sufficiently formed on the surface of the iron-based sintered alloy member, and when the content of Cr exceeds 9.5% by weight,
Alternatively, when the Mo content exceeds 5.5% by weight, C
It is recognized that r and Mo react with C that diffuses inside the iron-based sintered alloy due to carburization, so that the carbide formed in the matrix becomes coarse and the toughness of the iron-based sintered alloy member is impaired. It was Therefore, the contents of Cr and Mo are
The ranges are 7.0 to 9.5% by weight and 2.0 to 5.5% by weight, respectively.
Ｐは、Fe及びＣと反応して低融点の３元共晶を形成する
ものとなる液相を発生させることにより、鉄系焼結合金
の緻密化に寄与するものとなる。そして、実験の結果、
Ｐの含有量が0.7重量％未満である場合には、焼結時に
おける液相量が不足することとなり、多数の気孔が生じ
て、鉄系焼結合金部材の硬度が充分に得られず、また、
Ｐの含有量が1.5重量％を越える場合には、焼結時にお
ける液相量が過多となって組織が粗大化してしまうこと
が確認された。従って、Ｐの含有量は、0.7〜1.5重量％
の範囲とされる。P reacts with Fe and C to generate a liquid phase that forms a low-melting ternary eutectic, thereby contributing to the densification of the iron-based sintered alloy. And as a result of the experiment,
When the P content is less than 0.7% by weight, the liquid phase amount at the time of sintering becomes insufficient, a large number of pores are generated, and the hardness of the iron-based sintered alloy member cannot be sufficiently obtained, Also,
It has been confirmed that when the P content exceeds 1.5% by weight, the amount of liquid phase during sintering becomes excessive and the structure becomes coarse. Therefore, the P content is 0.7 to 1.5% by weight.
The range is.
また、鉄系焼結合金に対する浸炭処理にあたっての雰囲
気の炭素濃度が、0.7〜1.2％の範囲に設定されるのは、
以下の理由による。In addition, the carbon concentration of the atmosphere in the carburizing treatment for the iron-based sintered alloy is set in the range of 0.7 ~ 1.2%,
The reason is as follows.
即ち、各種の炭素濃度の雰囲気中で鉄系焼結合金に浸炭
処理を施す実験を行った結果、雰囲気の炭素濃度が0.7
％未満である場合には、浸炭処理によって鉄系焼結合金
の内部に拡散せしめられるＣが少量となり、鉄系焼結合
金の内部に含まれたCr及びMoの炭化物が充分に生成され
ないことになり、また、雰囲気の炭素濃度が1.2％を越
える場合には、焼結時において鉄系合金粉末に含まれた
ＣがCr及びMo等と結合することによりマトリックス中に
生成された炭化物が、浸炭処理によって鉄系焼結合金の
内部に拡散する、雰囲気中のＣと反応して粗大化するこ
とになり、鉄系焼結合金部材の靱性が低下してしまうこ
とが認められた。従って、鉄系焼結合金に対する浸炭処
理に際しての雰囲気の炭素農度は0.7〜1.2％の範囲にあ
るものとされる。That is, as a result of performing an experiment for carburizing an iron-based sintered alloy in an atmosphere of various carbon concentrations, the carbon concentration of the atmosphere was 0.7
If it is less than%, the amount of C diffused inside the iron-based sintered alloy by the carburizing process becomes small, and the carbides of Cr and Mo contained in the iron-based sintered alloy are not sufficiently generated. If the carbon concentration of the atmosphere exceeds 1.2%, the carbon contained in the iron-based alloy powder at the time of sintering is combined with Cr and Mo to form carbides in the matrix. It was confirmed that the treatment causes coarsening by reacting with C in the atmosphere, which diffuses inside the iron-based sintered alloy, and coarsens the iron-based sintered alloy member. Therefore, the carbon content of the atmosphere during the carburizing treatment of the iron-based sintered alloy is in the range of 0.7 to 1.2%.
さらに、鉄系焼結合金に対する浸炭処理が施されるに際
しての温度が、950℃を越えるものとされ、930℃より大
幅に高い場合には、浸炭処理にあたっての雰囲気中にお
けるＣが、鉄系焼結合金の内部におけるマトリックス中
の炭化物への拡散が促進されて、マトリックス中の炭化
物と活発に結合するのとなるため、鉄系焼結合金部材の
表面部分における充分な炭化物層の形成が妨げられると
いう問題を生じる。また、逆に、鉄系焼結合金に対する
浸炭処理が施されるに際しての温度が、900℃未満とさ
れ、930℃より大幅に低い場合には、浸炭処理にあたっ
ての雰囲気中におけるＣが、鉄系焼結合金の内部に充分
に拡散せず、そのため、鉄系焼結合金部材の表面部分に
おいて充分な炭化物層が形成されないという問題を生じ
ることになる。従って、鉄系焼結合金に対する浸炭処理
は、900〜950℃の温度のもとで施されるものとされる。Further, when the temperature for carburizing the iron-based sintered alloy is higher than 950 ° C and is significantly higher than 930 ° C, C in the atmosphere during the carburizing is iron-based. The diffusion of the binding gold into the carbide in the matrix is promoted and actively bonds with the carbide in the matrix, which prevents the formation of a sufficient carbide layer on the surface portion of the iron-based sintered alloy member. Causes the problem. On the contrary, when the temperature for carburizing the ferrous sintered alloy is less than 900 ° C, which is significantly lower than 930 ° C, C in the atmosphere for carburizing is iron-based. There is a problem in that it does not sufficiently diffuse inside the sintered alloy, and thus a sufficient carbide layer is not formed on the surface portion of the iron-based sintered alloy member. Therefore, the carburizing treatment for the iron-based sintered alloy is performed at a temperature of 900 to 950 ° C.
なお、参考までに、上述の如くの本発明に係る方法によ
って製造される鉄系焼結合金部材に対する比較例とし
て、２系統に区分される。本発明に係る方法以外の方法
によって製造された鉄系焼結合金部材（以下、比較用鉄
系焼結合金部材という）について述べる。For reference, the iron-based sintered alloy members manufactured by the method according to the present invention as described above are classified into two systems as comparative examples. An iron-based sintered alloy member manufactured by a method other than the method according to the present invention (hereinafter referred to as a comparative iron-based sintered alloy member) will be described.
第１の系統の比較用鉄系焼結合金部材は、以下の如くの
方法によって製造された。The comparative iron-based sintered alloy member of the first system was manufactured by the following method.
先ず、Crが12重量％含有され、さらに、Mn,Si,P及びＳ
が、夫々、１重量％,1重量％,0.043重量％及び0.03重量
％を越えない範囲で含有されるとともに、Feが残部とな
る組成を有した第１の合金粉末（SUS 410）と、Crが４
重量％,Moが９重量％,Pが2.4重量％,Cが4.2重量％，及
びFeが残部となる組成を有した第２の合金粉末とを、夫
々の粒度を150メッシュ以下とした状態で約8:2及び約3:
7の割合で混合することにより、下記の表−２に示され
る如くの成分組成を有する２種類の鉄系合金粉末（以
下、試料T5及びT6という）を得た。First, it contains 12% by weight of Cr, and further contains Mn, Si, P and S.
Of the first alloy powder (SUS 410), which has a composition in which Fe is the balance and is contained in a range not exceeding 1% by weight, 1% by weight, 0.043% by weight and 0.03% by weight, respectively, and Cr. Is 4
Wt%, Mo: 9 wt%, P: 2.4 wt%, C: 4.2 wt%, and a second alloy powder having a composition in which Fe is the balance, with the respective grain sizes being 150 mesh or less. About 8: 2 and about 3:
By mixing at a ratio of 7, two types of iron-based alloy powders (hereinafter referred to as samples T 5 and T 6 ) having the composition as shown in Table 2 below were obtained.
次に、炭素含有量が、本発明に係る方法において採られ
る1.2〜2.5重量％の範囲から外れた、0.84重量％及び2.
94重量％となされた試料T5及びT6の夫々に、バインダと
してパラフィン1.5重量％を添加して混合した後、5ton/
cm2の圧力をかけて圧縮し、10mm×30mm×50mmの直方体
状の圧粉体を、試料T5及びT6の夫々について形成した。 Then, the carbon content is out of the range of 1.2-2.5 wt% adopted in the method according to the present invention, 0.84 wt% and 2.
After adding 1.5% by weight of paraffin as a binder to each of the samples T 5 and T 6 which were determined to be 94% by weight and mixing them,
By compressing by applying a pressure of cm 2 , a 10 mm × 30 mm × 50 mm rectangular parallelepiped green compact was formed for each of samples T 5 and T 6 .
このようにして形成された圧粉体の夫々について、水素
ガス（H2）雰囲気中において600℃まで昇温加熱した
後、その状態を30分間保持し、予備焼結を行った。さら
に、得られた各予備焼結体を、真空炉中で、10℃/minの
加熱勾配をもって昇温加熱していき、試料T5に基づく予
備焼結体を、1080℃及び1100℃の焼結温度をもっての加
熱焼結状態に20分間保持し、その後930℃まで降温し
て、試料T5に基づく鉄系焼結合金を得た。また、試料T6
に基づく予備焼結体については、1060℃及び1080℃の焼
結温度をもっての加熱焼結状態に20分間保持し、その後
930℃まで降温して、試料T6に基づく鉄系焼結合金を得
た。Each of the green compacts thus formed was heated up to 600 ° C. in a hydrogen gas (H 2 ) atmosphere, held for 30 minutes, and pre-sintered. Further, each of the obtained pre-sintered bodies was heated in a vacuum furnace at a heating gradient of 10 ° C./min to heat the pre-sintered body based on the sample T 5 at 1080 ° C. and 1100 ° C. The heating and sintering state at the binding temperature was maintained for 20 minutes, and then the temperature was lowered to 930 ° C. to obtain an iron-based sintered alloy based on sample T 5 . Also, sample T 6
For the pre-sintered body based on, hold for 20 minutes in the heating and sintering state with the sintering temperature of 1060 ℃ and 1080 ℃, then
The temperature was lowered to 930 ° C., and an iron-based sintered alloy based on sample T 6 was obtained.
続いて、1080℃及び1100℃の焼結温度をもって焼結され
た、試料T5に基づく鉄系焼結合金、及び、1060℃及び10
80℃の焼結温度をもって焼結された、試料T6に基づく鉄
系焼結合金の各々に対し、炭素濃度が0.6,0.7,0.9,1.2
及び1.5％とされた５種の雰囲気の夫々の中において930
℃の温度のもとに40分間の浸炭処理を施した。Subsequently, an iron-based sintered alloy based on sample T 5 was sintered at a sintering temperature of 1080 ° C. and 1100 ° C., and 1060 ° C. and 10
For each of the iron-based sintered alloys based on sample T 6 which were sintered at a sintering temperature of 80 ° C, the carbon concentration was 0.6, 0.7, 0.9, 1.2.
And 930 in each of the 5 atmospheres, which are 1.5%
Carburizing treatment was performed for 40 minutes at a temperature of ° C.
そして、浸炭処理が施された各鉄系焼結合金を900℃ま
で降温して、窒素ガス（N2）による焼入れ処理を施し、
その後、560℃に降温した状態で100分間保持して焼戻し
処理を行うことにより、試料T5及びT6に基づく比較用鉄
系焼結合金部材を得た。Then, the carburized iron-based sintered alloys are cooled to 900 ° C., and quenched by nitrogen gas (N 2 ).
Then, the temperature was lowered to 560 ° C., and the tempered steel was held for 100 minutes to obtain a comparative ferrous sintered alloy member based on Samples T 5 and T 6 .
このようにして、試料T5及びT6に基づいて得られた比較
用鉄系焼結合金部材においては、そのいずれの表面部に
も安定した炭化物層が生成されていないことが確認され
た。In this way, it was confirmed that in the comparative iron-based sintered alloy members obtained based on Samples T 5 and T 6 , a stable carbide layer was not formed on any of the surface portions thereof.
また、第２の系統の比較用鉄系焼結合金部材は、以下の
如くの方法によって製造された。The comparative iron-based sintered alloy member of the second system was manufactured by the following method.
先ず、表−１に示される試料T3を用いて２個の圧粉体を
形成し、それらを水素ガス（H2）雰囲気中において600
℃まで昇温加熱した後、その状態を30分間保持して予備
焼結を行った。さらに、得られた２個の予備焼結体を、
真空炉中で、10℃/minの加熱勾配をもって昇温加熱して
いき、1080℃の焼結温度をもっての加熱焼結状態を20分
間保持し、その後930℃まで降温して、２個の鉄系焼結
合金を得た。First, two green compacts were formed by using the sample T 3 shown in Table 1, and the two green compacts were formed in a hydrogen gas (H 2 ) atmosphere at 600
After heating up to 0 ° C., the state was maintained for 30 minutes for pre-sintering. Furthermore, the obtained two pre-sintered bodies were
In a vacuum furnace, heating and heating are performed with a heating gradient of 10 ° C / min, the heating and sintering state at a sintering temperature of 1080 ° C is maintained for 20 minutes, then the temperature is lowered to 930 ° C, and two iron A system sintered alloy was obtained.
続いて、得られた２個の鉄系焼結合金の一方に対し、浸
炭処理温度が、本発明に係る方法において採られる900
〜950℃の範囲から外れた880℃となされたもので、炭素
濃度が0.7％とされた雰囲気中において40分間の浸炭処
理を施し、また、他方に対し、浸炭処理温度が、同じく
本発明に係る方法において採られる900〜950℃の範囲か
ら外れた960℃となされたもので、炭素濃度が0.7％とさ
れた雰囲気中において40分間の浸炭処理を施した。そし
て、浸炭処理が施された２個の鉄系焼結合金のうちの、
880℃の温度で浸炭処理されたものを880℃に維持したも
とで窒素ガス（N2）による焼入れ処理を施し、その後、
560℃に降温した状態で10分間保持して焼戻し処理を行
うことにより、比較用鉄系焼結合金部材を得、また、96
0℃の温度で浸炭処理されたものを900℃に降温して窒素
ガス（N2）による焼入れ処理を施し、その後、560℃に
降温した状態で100分間保持して焼戻し処理を行うこと
により、他の比較用鉄系焼結合金部材を得た。Subsequently, a carburizing temperature is applied to one of the two obtained iron-based sintered alloys in the method according to the present invention.
~ 950 ℃ deviated from the range of 880 ℃, the carburizing treatment is carried out for 40 minutes in an atmosphere with a carbon concentration of 0.7%, on the other hand, the carburizing temperature is the same as in the present invention. Carburizing treatment was performed for 40 minutes in an atmosphere with a carbon concentration of 0.7%, which was set to 960 ° C outside the range of 900 to 950 ° C adopted in the method. Of the two iron-based sintered alloys that have been carburized,
Carburizing at 880 ° C is performed at 880 ° C, then quenching is performed with nitrogen gas (N 2 ).
A ferrous sintered alloy member for comparison was obtained by holding for 10 minutes at a temperature lowered to 560 ° C and tempering treatment.
What was carburized at a temperature of 0 ° C was cooled to 900 ° C and subjected to quenching treatment with nitrogen gas (N 2 ), and then the temperature was lowered to 560 ° C and held for 100 minutes to perform tempering treatment. Other comparative iron-based sintered alloy members were obtained.
このようにして、880℃の温度での浸炭処理がなされ
た、試料T3に基づく比較用鉄系焼結合金部材、及び、96
0℃の温度での浸炭処理がなされた、試料T3に基づく比
較用鉄系焼結合金部材においては、そのいずれの表面部
にも安定した炭化物層が生成されていないことが確認さ
れた。In this way, a carburizing treatment at a temperature of 880 ° C., a comparative iron-based sintered alloy member based on sample T 3 , and 96
It was confirmed that in the comparative iron-based sintered alloy member based on the sample T 3 which was carburized at the temperature of 0 ° C., a stable carbide layer was not formed on any of the surface portions thereof.
（発明の効果） 以上の説明から明らかな如く、本発明に係る耐摩耗性に
優れた鉄系焼結合金部材の製造法によれば、鉄系焼結合
金に対する浸炭処理が行われ、浸炭処理にあたっての雰
囲気中に含まれる炭素が、鉄系焼結合金の内部に拡散
し、その鉄系焼結合金に含まれるCr及びMoのうちの少な
く１種と結合して、鉄系焼結合金の表面部分に炭化物を
生成するようにされるので、内部硬度が大であることに
加えて、表面部分に、Crの炭化物及びMoの炭化物のうち
の少なくとも一方の層から成る適正な硬化層が形成され
て、その表面部分の硬度が向上せしめられた鉄系焼結合
金部材を得ることができる。(Effects of the Invention) As is clear from the above description, according to the method for producing an iron-based sintered alloy member having excellent wear resistance according to the present invention, the iron-based sintered alloy is subjected to carburizing treatment and carburizing treatment. The carbon contained in the atmosphere at the time of diffusion diffuses inside the iron-based sintered alloy and combines with at least one of Cr and Mo contained in the iron-based sintered alloy to form an iron-based sintered alloy. Since the surface portion is made to generate carbide, in addition to having a large internal hardness, a proper hardened layer composed of at least one of the carbide of Cr and the carbide of Mo is formed on the surface portion. As a result, it is possible to obtain an iron-based sintered alloy member whose surface portion has improved hardness.
しかも、鉄系焼結合金に対する浸炭処理に要する時間
は、例えば、ガス窒化法に従って鉄系焼結合金が加熱処
理されるに要される時間に比して大幅に短縮され、それ
により、比較的高い生産効率が得られるもとになり、ま
た、鉄系焼結合金の表面部分における硬化層の形成に要
するコストは、金属溶射法に従って鉄系焼結合金の表面
に溶融金属の微粒子が吹き付けられる場合に比して、著
しく低減される。Moreover, the time required for carburizing the iron-based sintered alloy is significantly shorter than the time required for heat-treating the iron-based sintered alloy according to, for example, the gas nitriding method. High production efficiency is obtained, and the cost required for forming a hardened layer on the surface of the iron-based sintered alloy is that fine particles of molten metal are sprayed on the surface of the iron-based sintered alloy according to the metal spraying method. Compared with the case, it is significantly reduced.
図は本発明に係る耐摩耗性に優れた鉄系焼結合金部材の
製造法の一例によって製造された鉄系焼結合金部材の金
属組織を示す写真である。The figure is a photograph showing a metallographic structure of an iron-based sintered alloy member manufactured by an example of a method for manufacturing an iron-based sintered alloy member having excellent wear resistance according to the present invention.
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 昭59−31844（ＪＰ，Ａ) 特開 昭56−142868（ＪＰ，Ａ) 特開 昭52−152805（ＪＰ，Ａ) ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-59-31844 (JP, A) JP-A-56-142868 (JP, A) JP-A-52-152805 (JP, A)
Claims (1)
のクロム及び2.0〜5.5重量％のモリブデンのうちの少な
くとも１種とを含有する鉄系焼結合金に対して、炭素濃
度が0.7〜1.2％の雰囲気中において900〜950℃の温度で
浸炭処理を施し、上記鉄系焼結合金の表面にクロムの炭
化物及びモリブデンの炭化物のうちの少なくとも一方か
ら成る炭化物層を形成することを特徴とする耐摩耗性に
優れた鉄系焼結合金部材の製造法。1. 1.2 to 2.5% by weight of carbon and 7.0 to 9.5% by weight
Carbide treatment at a temperature of 900 to 950 ° C in an atmosphere of carbon concentration of 0.7 to 1.2% for an iron-based sintered alloy containing at least one of chromium and 2.0 to 5.5% by weight of molybdenum. A method for producing an iron-based sintered alloy member having excellent wear resistance, characterized in that a carbide layer made of at least one of chromium carbide and molybdenum carbide is formed on the surface of the iron-based sintered alloy. .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18304386A JPH0717995B2 (en) | 1986-08-04 | 1986-08-04 | Manufacturing method of ferrous sintered alloy members with excellent wear resistance |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18304386A JPH0717995B2 (en) | 1986-08-04 | 1986-08-04 | Manufacturing method of ferrous sintered alloy members with excellent wear resistance |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6338566A JPS6338566A (en) | 1988-02-19 |
| JPH0717995B2 true JPH0717995B2 (en) | 1995-03-01 |
Family
ID=16128741
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP18304386A Expired - Lifetime JPH0717995B2 (en) | 1986-08-04 | 1986-08-04 | Manufacturing method of ferrous sintered alloy members with excellent wear resistance |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0717995B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AT505699B1 (en) * | 2007-09-03 | 2010-10-15 | Miba Sinter Austria Gmbh | METHOD FOR PRODUCING A SINTERED CERTAIN COMPONENT |
-
1986
- 1986-08-04 JP JP18304386A patent/JPH0717995B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6338566A (en) | 1988-02-19 |
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