JP2005200698A - Iron-based powder mixture for high-strength sintered component - Google Patents
Iron-based powder mixture for high-strength sintered component Download PDFInfo
- Publication number
- JP2005200698A JP2005200698A JP2004007533A JP2004007533A JP2005200698A JP 2005200698 A JP2005200698 A JP 2005200698A JP 2004007533 A JP2004007533 A JP 2004007533A JP 2004007533 A JP2004007533 A JP 2004007533A JP 2005200698 A JP2005200698 A JP 2005200698A
- Authority
- JP
- Japan
- Prior art keywords
- powder
- mass
- iron
- strength
- sintering
- 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.)
- Granted
Links
Landscapes
- Powder Metallurgy (AREA)
Abstract
Description
本発明は、粉末冶金用鉄基粉末混合物に関し、特に自動車用の高強度焼結部品の製造に適用して好適なものである。 The present invention relates to an iron-based powder mixture for powder metallurgy, and is particularly suitable for application to the production of high-strength sintered parts for automobiles.
金属粉を金型内で加圧−成形したのち、焼結して焼結体とする粉末冶金法は、複雑な形状の機械部品も精度よく製造することができるため、高い寸法精度が要求されるギヤ等の自動車用部品の製造に広く利用されている。
金属粉として鉄粉を用いる場合には、通常、鉄粉にCu粉や黒鉛粉等の合金成分を混合し、さらに成形性を向上させるための潤滑剤を 0.8〜1.2 質量%程度混合した後、成形し、ついで焼結を行うことにより、 5.0〜7.2 g/cm3 程度の密度を有する焼結体としている。
また、これらの自動車用部品には、高強度であることが要求されている。そこで、一層の強度向上のために、合金元素を添加した焼結体に、さらに焼入−焼戻等の熱処理を施して製品化することが一般的に行われている。
The powder metallurgy method, in which metal powder is pressed and molded in a mold and then sintered to form a sintered body, can be used to accurately manufacture mechanical parts with complex shapes, so high dimensional accuracy is required. It is widely used in the manufacture of automotive parts such as gears.
When using iron powder as the metal powder, usually, alloy components such as Cu powder and graphite powder are mixed with the iron powder, and further, about 0.8 to 1.2% by mass of a lubricant for improving formability is mixed. By forming and then sintering, a sintered body having a density of about 5.0 to 7.2 g / cm 3 is obtained.
Further, these automotive parts are required to have high strength. Therefore, in order to further improve the strength, it is a common practice to produce a product by further subjecting a sintered body to which an alloy element is added to a heat treatment such as quenching and tempering.
例えば、特許文献1には、高強度粉末冶金部品用原料粉として、C,N,Si,Al,Oを低減すると共に、Mn,Cr,Mo,Vのうちから選んだ1種または2種以上の元素を予合金成分として含有させ、残部はFeおよび不可避的不純物の組成になる、圧縮性、成形性および熱処理特性に優れる合金鋼粉が提案されている。 For example, in Patent Document 1, as raw material powder for high-strength powder metallurgy parts, C, N, Si, Al, and O are reduced, and one or more selected from Mn, Cr, Mo, and V are selected. These alloy steel powders having excellent compressibility, formability and heat treatment characteristics have been proposed in which the above elements are contained as a prealloy component and the balance is composed of Fe and inevitable impurities.
また、特許文献2には、自動車用高強度部品用原料粉として、鉄粉の表面にCu,Ni,Moの粉末を同時に付着拡散させた、熱処理における寸法変化のばらつきの小さい部分合金化合金鋼粉が提案されている。 Further, Patent Document 2 discloses a partially alloyed alloy steel with small variation in dimensional change during heat treatment, in which Cu, Ni, and Mo powders are simultaneously adhered and diffused on the surface of iron powder as raw material powder for high-strength parts for automobiles. Powder has been proposed.
ところで、最近では、焼結部品の製造に際し、製造コスト低減のために、弱酸化性雰囲気中で焼結温度を低下させた低温焼結や、焼結後における熱処理の省略が指向されている。
そのため、かような低温焼結を実施した場合であっても、あるいはその後の熱処理を省略したとしても、高強度の焼結部品が確保できる原料粉の開発が要望されている。
By the way, recently, when manufacturing sintered parts, in order to reduce manufacturing costs, low-temperature sintering in which the sintering temperature is lowered in a weakly oxidizing atmosphere and heat treatment after sintering are directed to be omitted.
Therefore, there is a demand for the development of raw material powder that can secure a high-strength sintered part even when such low-temperature sintering is performed or even if the subsequent heat treatment is omitted.
しかしながら、特許文献1に記載されたような、Cr,Mnなどの易酸化性合金元素を溶鋼の状態で予合金化させた予合金化合金鋼粉を用いて、弱酸化性雰囲気中で焼結すると、予合金化された合金元素が酸化されて、所望の強度を有する焼結部品が得られないという問題があった。
この点、特許文献2に記載のような、鉄粉に、NiやMo,Cu等の合金元素を部分合金化させた部分合金化合金鋼粉を用いた場合には、合金元素の酸化という問題はないが、この部分合金化合金鋼粉は、圧縮性が低いだけでなく、焼結後の熱処理によって高強度の確保を意図しているため、焼結のままでは引張強さ:800 MPa 以上の高強度を達成できないという問題があった。
However, as described in Patent Document 1, sintering is performed in a weakly oxidizing atmosphere by using a prealloyed alloy steel powder obtained by prealloying an easily oxidizable alloy element such as Cr or Mn in a molten steel state. Then, there is a problem that the prealloyed alloy element is oxidized and a sintered part having a desired strength cannot be obtained.
In this regard, as described in Patent Document 2, when a partially alloyed alloy steel powder obtained by partially alloying an alloy element such as Ni, Mo, or Cu is used for the iron powder, there is a problem of oxidation of the alloy element. However, this partially alloyed alloy steel powder is not only low in compressibility but also intended to ensure high strength by heat treatment after sintering. There was a problem that the high strength of could not be achieved.
このような問題に対し、特許文献3では、重量比率で、Ni:3〜5%、Mo:0.4 〜0.7%、残部Feからなる組成の合金粉末に、Cu粉を1〜2%、Ni粉を1〜3%、黒鉛粉を焼結後のC量が 0.2〜0.7 %になるように混合した混合粉末を、圧縮成形し、得られた圧粉体を非酸化性雰囲気中で焼結し、その際、焼結炉中で5〜20℃/minの速度で冷却することからなる鉄系焼結合金の製造方法が提案されている。 In order to solve such a problem, in Patent Document 3, in terms of weight ratio, Ni: 3 to 5%, Mo: 0.4 to 0.7%, and an alloy powder composed of the balance Fe, Cu powder is 1 to 2%, Ni powder 1 to 3% and graphite powder mixed so that the C content after sintering is 0.2 to 0.7%, compression molded, and the resulting green compact is sintered in a non-oxidizing atmosphere. At that time, a method for producing an iron-based sintered alloy comprising cooling in a sintering furnace at a rate of 5 to 20 ° C./min has been proposed.
また、特許文献4には、重量比率で、Ni:0.5 〜3質量%およびMo:0.7 超〜4質量、残部Feおよび不可避的不純物の組成になる合金粉末に、Ni粉を1〜5質量%、Cu粉を 0.5〜3質量%、黒鉛粉を0.2 〜0.9 質量%混合させた鉄基混合粉が提案されている。 Further, Patent Document 4 discloses that Ni powder is contained in an alloy powder having a composition of Ni: 0.5 to 3 mass% and Mo: more than 0.7 to 4 mass, the balance Fe and inevitable impurities in a weight ratio of 1 to 5 mass%. An iron-based mixed powder in which 0.5 to 3% by mass of Cu powder and 0.2 to 0.9% by mass of graphite powder are mixed has been proposed.
しかしながら、上記特許文献3および特許文献4に記載された技術では、いずれも合金鋼粉中にNiが予合金化されているため、焼入れ性は高いものの、合金鋼粉の圧縮性が低下することから、高い圧粉体密度が得られず、そのため高強度の焼結体が得られないという問題があった。
また、いずれの文献でも、潤滑剤を 0.8質量%程度添加しているため、脱ろう時間の短い焼結条件では、焼結の初期段階まで脱ろうに費やされ、実質的な焼結時間が短くなるため、高強度の焼結体が得られないという問題があることも判明した。
However, in the techniques described in Patent Document 3 and Patent Document 4 described above, since Ni is pre-alloyed in the alloy steel powder, the hardenability is high, but the compressibility of the alloy steel powder is reduced. Therefore, there has been a problem that a high green compact density cannot be obtained, and thus a high strength sintered body cannot be obtained.
In all of the documents, about 0.8% by mass of the lubricant is added. Under sintering conditions with a short dewaxing time, it takes time to dewax up to the initial stage of sintering, and the substantial sintering time is reduced. It has also been found that there is a problem that a high-strength sintered body cannot be obtained due to the shortening.
本発明は、上記の実状に鑑み開発されたもので、高い圧粉体密度が得られ、また脱ろう時間の短い厳しい焼結条件下でも、焼結のままで引張強さが 800 MPa以上の高強度焼結体を得ることができる鉄基粉末混合物を提案することを目的とする。 The present invention has been developed in view of the above circumstances, and can provide a high green compact density and a tensile strength of 800 MPa or more as it is sintered even under severe sintering conditions with a short dewaxing time. The object is to propose an iron-based powder mixture from which a high-strength sintered body can be obtained.
さて、発明者らは、上記の課題を解決すべく、潤滑剤の種類および添加方法について鋭意検討を重ねた結果、以下に述べる知見を得た。
すなわち、潤滑剤中に適量の極圧添加剤を含有させることにより、圧粉成形時における抜出力を上昇させることなしに、潤滑剤の添加量を効果的に低減することができ、その結果、圧粉体密度が向上するだけでなく、焼結時における潤滑剤の脱ろう効率も向上するため、焼結体の強度が有利に向上するとの知見を得た。
本発明は、上記の知見に基づき、さらに検討を加えた末に、完成されたものである。
Now, as a result of intensive studies on the types and addition methods of lubricants, the inventors have obtained the following knowledge.
That is, by adding an appropriate amount of extreme pressure additive in the lubricant, the additive amount of the lubricant can be effectively reduced without increasing the output during compaction, and as a result, It has been found that not only the green density increases but also the dewaxing efficiency of the lubricant during sintering improves, so that the strength of the sintered body is advantageously improved.
The present invention has been completed after further studies based on the above findings.
すなわち、本発明は、NiおよびMoを予合金化した合金鋼粉に、Ni粉、Cu粉および黒鉛粉を混合した鉄基混合粉:100 質量部に対し、有機ハロゲン化合物、有機いおう化合物、有機りん化合物および有機金属化合物のうちから選んだ少なくとも1種を少なくとも10質量%含有する潤滑剤が0.05〜0.5 質量部の割合で添加され、前記合金鋼粉におけるNiおよびMoの予合金化率が、Ni:0.5 〜3質量%、Mo:0.7 超〜4質量%、また前記鉄基混合物におけるNi粉、Cu粉および黒鉛粉の混合割合が、Ni粉:0.5 〜5質量%、Cu粉:0.5 〜3質量%、黒鉛粉:0.2 〜1.0 質量%であることを特徴とする高強度焼結部品用の鉄基粉末混合物である。 That is, the present invention relates to an iron-based mixed powder in which Ni powder, Cu powder and graphite powder are mixed with alloy steel powder prealloyed with Ni and Mo: 100 parts by mass, an organic halogen compound, an organic sulfur compound, an organic A lubricant containing at least 10% by mass of at least one selected from phosphorus compounds and organometallic compounds is added in a proportion of 0.05 to 0.5 parts by mass, and the prealloying rate of Ni and Mo in the alloy steel powder is as follows: Ni: 0.5-3 mass%, Mo: more than 0.7-4 mass%, and the mixing ratio of Ni powder, Cu powder and graphite powder in the iron-based mixture is Ni powder: 0.5-5 mass%, Cu powder: 0.5- 3% by mass, graphite powder: 0.2 to 1.0% by mass, an iron-based powder mixture for high-strength sintered parts.
本発明の鉄基粉末混合物を原料として使用することにより、高密度の高強度焼結部品を得ることができる。
また、本発明の鉄基粉末混合物は、比較的低い焼結温度でも焼結が促進されて高強度の焼結部品を得ることができる。
By using the iron-based powder mixture of the present invention as a raw material, a high-density, high-strength sintered part can be obtained.
In addition, the iron-based powder mixture of the present invention can be sintered at a relatively low sintering temperature to obtain a high-strength sintered part.
以下、本発明を具体的に説明する。
まず、本発明の主原料である合金鋼粉について説明する。本発明では、強度向上のための合金元素として、Ni,MoおよびCuを選択した。これら合金元素は、炭化水素変成ガス雰囲気中で焼結を行っても、酸化することがなく、強度を効率良く向上させることができる。
これらの合金元素のうち、Niは、焼結の活性化による空孔の微細化および基地強化のために、粉体による添加と予合金化による添加の両方とする。
また、Cuは、焼結時に液相を形成して焼結を促進させるために、粉体で添加する。
さらに、Moは、粉体で添加すると拡散し難いので高強度の合金を形成し難く、また予合金化しても圧縮性の低下が少ないため、予合金化により添加する。
The present invention will be specifically described below.
First, the alloy steel powder that is the main raw material of the present invention will be described. In the present invention, Ni, Mo and Cu were selected as alloy elements for improving the strength. Even if these alloy elements are sintered in a hydrocarbon-modified gas atmosphere, they are not oxidized and the strength can be improved efficiently.
Of these alloy elements, Ni is added both by powder and by prealloying in order to refine pores by activation of sintering and strengthen the base.
Further, Cu is added as a powder to form a liquid phase during sintering and promote sintering.
Furthermore, Mo is difficult to diffuse when added as a powder, so that it is difficult to form a high-strength alloy, and even when pre-alloyed, there is little decrease in compressibility, so it is added by pre-alloying.
上述したとおり、本発明における合金鋼粉は、Ni,Moが予合金化された予合金化合金鋼粉である。かかる予合金化合金鋼粉は、所定量の合金元素を含有する溶鋼を、溶製したのち、例えば水アトマイズにより製造することができる。水アトマイズは、通常公知の装置および方法を用いて行えばよく、特に限定されることはない。なお、この予合金化合金鋼粉は、水アトマイズ後、常法に従い、仕上還元処理、ついで解砕処理が施されるのは言うまでもない。 As described above, the alloy steel powder in the present invention is a pre-alloyed alloy steel powder in which Ni and Mo are pre-alloyed. Such pre-alloyed alloy steel powder can be produced, for example, by water atomization after melting molten steel containing a predetermined amount of alloy elements. Water atomization may be performed using a generally known apparatus and method, and is not particularly limited. Needless to say, the prealloyed alloy steel powder is subjected to finish reduction treatment and then pulverization treatment in accordance with a conventional method after water atomization.
上述した予合金化合金鋼粉におけるNiおよびMoの好適含有量(予合金化率)は次のとおりである。
Ni:0.5 〜3質量%
Niは、マルテンサイト変態開始温度を低温側に移行させることにより、基地組織を微細化して、強度を向上させる有用元素である。しかしながら、Niの予合金化率が 0.5質量%未満では強度の向上効果が充分ではなく、一方3質量%を超えて予合金化させると鋼粉が著しく硬化し、圧縮性が著しく低下して、強度および靭性がともに低下する。このため、Niの予合金化率は 0.5〜3質量%の範囲に限定した。好ましくは 0.5〜2質量%の範囲である。
The preferred contents of Ni and Mo (prealloying rate) in the prealloyed alloy steel powder described above are as follows.
Ni: 0.5-3 mass%
Ni is a useful element that refines the matrix structure and improves the strength by shifting the martensitic transformation start temperature to the low temperature side. However, if the prealloying rate of Ni is less than 0.5% by mass, the effect of improving the strength is not sufficient. On the other hand, if prealloying exceeding 3% by mass, the steel powder is markedly hardened and the compressibility is significantly reduced. Both strength and toughness are reduced. For this reason, the prealloying rate of Ni was limited to the range of 0.5-3 mass%. Preferably it is the range of 0.5-2 mass%.
Mo:0.7 超〜4質量%
Moは、固溶強化および変態強化により強度を向上させる有用元素であり、しかも予合金化しても圧縮性の低下は少ない。しかしながら、Moの予合金化率が 0.7質量%以下では強度を向上させる効果が十分でなく、一方4質量%を超えて予合金化させると鋼粉が硬化し、圧縮性が著しく低下して、強度および靭性がともに低下する。このため、Moの予合金化率は 0.7超〜4質量%の範囲に限定した。好ましくは 0.7超〜3質量%の範囲である。
また、Cは、鋼粉の硬化による圧縮性の低下を避けるために、0.02質量%以下が好適である。
Mo: More than 0.7 to 4% by mass
Mo is a useful element that improves strength by solid solution strengthening and transformation strengthening, and even when pre-alloyed, there is little decrease in compressibility. However, when the prealloying rate of Mo is 0.7 mass% or less, the effect of improving the strength is not sufficient, whereas when prealloying exceeding 4 mass%, the steel powder is hardened and the compressibility is remarkably reduced. Both strength and toughness are reduced. For this reason, the prealloying rate of Mo was limited to the range of more than 0.7 to 4% by mass. Preferably, it is in the range of more than 0.7 to 3% by mass.
C is preferably 0.02% by mass or less in order to avoid a decrease in compressibility due to hardening of the steel powder.
合金鋼粉において、上記した成分以外は、Feおよび不可避的不純物である。不可避的不純物のうち、SiやMn,S,P等は、それぞれSi:0.1 質量%以下、Mn:0.3 質量%以下、S:0.02質量%以下、P:0.02質量%以下で許容できる。 In the alloy steel powder, other than the above-mentioned components are Fe and inevitable impurities. Among the inevitable impurities, Si, Mn, S, P, etc. are acceptable at Si: 0.1% by mass or less, Mn: 0.3% by mass or less, S: 0.02% by mass or less, and P: 0.02% by mass or less, respectively.
次に、鉄基混合粉における、Ni粉、Cu粉および黒鉛粉の混合割合を前記の範囲に限定した理由について説明する。
なお、鉄基混合粉中における各粉体の混合割合は、合金鋼粉、Ni粉、Cu粉および黒鉛粉の合計量(混合粉全量)に対する質量%で表示する。
Next, the reason why the mixing ratio of Ni powder, Cu powder and graphite powder in the iron-based mixed powder is limited to the above range will be described.
In addition, the mixing ratio of each powder in the iron-based mixed powder is expressed by mass% with respect to the total amount of alloy steel powder, Ni powder, Cu powder and graphite powder (mixed powder total amount).
Ni粉:0.5 〜5質量%
Ni粉は、焼結を活性化し、空孔を微細化して、強度を向上させるために添加する。しかしながら、Ni粉の混合割合が 0.5質量%に満たないと焼結を活性化させる効果が十分でなく、一方5質量%を超えると残留オーステナイトが著しく増加して、強度の低下を招く。このため、Ni粉の混合割合は 0.5〜5質量%の範囲に限定した。好ましくは2〜4質量%の範囲である。
なお、Ni粉としては、熱分解法により作成したカルボニルニッケル粉、Ni酸化物を還元して作成したNi粉など公知のものを用いればよい。
Ni powder: 0.5-5% by mass
Ni powder is added to activate sintering, refine pores, and improve strength. However, if the mixing ratio of Ni powder is less than 0.5% by mass, the effect of activating the sintering is not sufficient. On the other hand, if it exceeds 5% by mass, the retained austenite is remarkably increased and the strength is lowered. For this reason, the mixing ratio of Ni powder was limited to the range of 0.5-5 mass%. Preferably it is the range of 2-4 mass%.
In addition, as Ni powder, what is necessary is just to use carbonyl nickel powder produced by the thermal decomposition method, Ni powder produced by reducing Ni oxide, and the like.
Cu粉:0.5 〜3質量%
Cu粉は、焼結時に液相形成により空孔を球状化して焼結を促進し、強度を向上させるため添加する。しかしながら、Cu粉の混合割合が 0.5質量%未満では強度を向上させる効果が十分でなく、一方3質量%を超えると脆化する。このため、Cuの混合割合は 0.5〜3質量%の範囲とした。好ましくは1〜2質量%の範囲である。
なお、Cu粉としては、電解Cu粉やアトマイズCu粉など公知のものを用いればよい。
Cu powder: 0.5-3 mass%
Cu powder is added to spheroidize the pores by forming a liquid phase during sintering to promote sintering and improve strength. However, if the mixing ratio of the Cu powder is less than 0.5% by mass, the effect of improving the strength is not sufficient, while if it exceeds 3% by mass, it becomes brittle. For this reason, the mixing ratio of Cu was set to a range of 0.5 to 3% by mass. Preferably it is the range of 1-2 mass%.
In addition, as Cu powder, what is necessary is just to use well-known things, such as electrolytic Cu powder and atomized Cu powder.
黒鉛粉:0.2 〜1.0 質量%
黒鉛粉は、焼結時に鉄粉中に拡散して固溶強化により強度を高くする元素である。しかしながら、黒鉛粉の混合割合が 0.2質量%未満では強度を向上させる効果が十分でなく、一方 1.0質量%を超えると、初析セメンタイトが粒界に析出し、強度が低下する。このため、黒鉛粉の混合割合は 0.2〜1.0 質量%の範囲とした。
Graphite powder: 0.2 to 1.0 mass%
Graphite powder is an element that diffuses into iron powder during sintering and increases strength by solid solution strengthening. However, when the mixing ratio of the graphite powder is less than 0.2% by mass, the effect of improving the strength is not sufficient. On the other hand, when it exceeds 1.0% by mass, pro-eutectoid cementite precipitates at the grain boundary and the strength is lowered. For this reason, the mixing ratio of the graphite powder is set in the range of 0.2 to 1.0% by mass.
次に、本発明に従う潤滑剤について説明する。
さて、粉末成形において、潤滑剤は、成形時における粉末同士および粉末と金型との間の摩擦の低減、さらには成形後の金型からの抜出力の低下を目的として添加されるが、圧粉体密度を高める観点からは、むしろ逆効果であり、潤滑剤の添加量はできるかぎり低減した方が好ましい。
従って、できるだけ少ない潤滑剤添加量で、粉末同士および粉末と金型との間の摩擦を低減し、かつ成形後の金型からの抜出力を低下することができれば、圧粉体密度を有利に向上させることが可能になる。
Next, the lubricant according to the present invention will be described.
Now, in powder molding, a lubricant is added for the purpose of reducing friction between powders during molding and between the powder and the mold, and further for reducing output from the mold after molding. From the viewpoint of increasing the powder density, it is rather counterproductive, and it is preferable to reduce the amount of lubricant added as much as possible.
Therefore, if the amount of lubricant added is as small as possible and the friction between the powders and between the powder and the mold can be reduced and the punching force from the mold after molding can be reduced, the green compact density will be advantageous. It becomes possible to improve.
そこで、上記の観点から、潤滑剤の種類について検討を重ねた。
その結果、潤滑剤の一部または全部について、極圧添加剤を利用すれば、潤滑剤の総添加量を有利に低減できることが究明されたのである。
In view of the above, the types of lubricants have been studied repeatedly.
As a result, it has been found that the total amount of lubricant can be advantageously reduced by using an extreme pressure additive for part or all of the lubricant.
極圧添加剤は、金属と反応して熱的に安定な潤滑膜を形成する。本発明の場合、添加した極圧添加剤が、成形時に合金鋼粉と反応し、合金鋼粉の表面に潤滑層を形成する。この潤滑層により、合金鋼粉同士および合金鋼粉と金型との接触が防止されるので、良好な潤滑状態で成形することが可能となる。しかも、極圧添加剤による潤滑膜は、熱的に安定しているため、連続成形により金型の温度が上昇しても、熱劣化を起こさず、安定した潤滑性を維持することができる。 The extreme pressure additive reacts with the metal to form a thermally stable lubricating film. In the case of the present invention, the added extreme pressure additive reacts with the alloy steel powder during forming, and forms a lubricating layer on the surface of the alloy steel powder. This lubrication layer prevents the alloy steel powders from contacting each other and between the alloy steel powder and the mold, so that it can be molded in a good lubrication state. In addition, since the lubricating film made of the extreme pressure additive is thermally stable, even if the temperature of the mold rises due to continuous molding, thermal degradation does not occur and stable lubricity can be maintained.
本発明に適用可能な極圧添加剤としては、有機ハロゲン化合物、有機いおう化合物、有機りん化合物および有機金属化合物等が挙げられる。
具体的には、塩素化パラフィン、オレフィンポリサルファイド、ジペンジルジサルファイド、アルキルおよびアリルリン酸エステル、アルキルおよびアリル亜エステル、りん酸エステルのアミン塩、チオリン酸エステル、チオリン酸エステルのアミン塩、ジブチルジチオカルバミン酸モリブデンおよびジ−2−エチルヘキシルホスホロジチオエートモリブデン塩等が挙げられる。なお、これらは、2種以上を混合して使用することもできる。
また、極圧添加剤以外の潤滑剤としては、ステアリン酸亜鉛およびオレイン酸などの公知の粉末成形用潤滑剤を好適に使用することができる。
Examples of extreme pressure additives applicable to the present invention include organic halogen compounds, organic sulfur compounds, organic phosphorus compounds, and organometallic compounds.
Specifically, chlorinated paraffin, olefin polysulfide, dipentyl disulfide, alkyl and allyl phosphate ester, alkyl and allyl subester, amine salt of phosphate ester, thiophosphate ester, amine salt of thiophosphate ester, dibutyldithiocarbamine Examples include molybdenum acid and di-2-ethylhexyl phosphorodithioate molybdenum salt. In addition, these can also be used in mixture of 2 or more types.
As the lubricant other than the extreme pressure additive, known powder molding lubricants such as zinc stearate and oleic acid can be suitably used.
本発明では、上記した極圧添加剤を、潤滑剤中に、少なくとも10質量%含有する。というのは、極圧添加剤の含有比率が10質量%に満たないと、十分な潤滑効果が得られず、抜出性が低下するからである。
なお、極圧添加剤の含有比率の上限は特に限定されることはなく、潤滑剤として極圧添加剤のみを使用することもできるが、引張強さをさらに大きくするには80質量%以下で使用することが好適である。
In the present invention, the above extreme pressure additive is contained in the lubricant at least 10% by mass. This is because if the content ratio of the extreme pressure additive is less than 10% by mass, a sufficient lubricating effect cannot be obtained and the drawability is lowered.
In addition, the upper limit of the content ratio of the extreme pressure additive is not particularly limited, and only the extreme pressure additive can be used as a lubricant, but in order to further increase the tensile strength, it is 80% by mass or less. It is preferred to use.
上述したように、潤滑剤の一部または全部として、極圧添加剤を利用することにより、従来に比べて潤滑剤の総添加量を低減できることができる。
すなわち、本発明では、潤滑剤の添加量は、合金鋼粉、Ni粉、Cu粉および黒鉛粉の混合体である鉄基混合粉:100 質量部に対し、0.05〜0.5 質量部で済む。
この点、従来の潤滑剤の添加量は、粉末同士および粉末−金型間の摩擦の低減および金型からの抜出力の低下の面から約 0.8質量部であったことは、前述したとおりである。
As described above, by using an extreme pressure additive as part or all of the lubricant, the total amount of lubricant can be reduced as compared with the conventional case.
That is, in the present invention, the addition amount of the lubricant may be 0.05 to 0.5 parts by mass with respect to 100 parts by mass of iron-based mixed powder that is a mixture of alloy steel powder, Ni powder, Cu powder, and graphite powder.
In this respect, the amount of conventional lubricant added was about 0.8 parts by mass from the viewpoints of reducing friction between powders and between the powder and the mold and reducing the output force from the mold, as described above. is there.
なお、極圧添加剤を含む潤滑剤は、合金鋼粉、Ni粉、Cu粉、黒鉛粉の混合体である鉄基混合粉に単に混合する、あるいは鉄基混合粉に潤滑剤を混合した後、加熱・冷却して、粉末に潤滑剤を付着させる形で添加してもよい。付着させた後に、さらに粉末の潤滑剤を添加することもできる。
また、前記の付着工程で、潤滑剤をバインダーとして、Ni粉、Cu粉および黒鉛粉を付着させてもよい。このようにすることにより、Ni粉、Cu粉および黒鉛粉の偏析を防止することができる。また、さらに粉末の潤滑剤を添加することもできる。
Note that the lubricant containing the extreme pressure additive is simply mixed with the iron-based mixed powder, which is a mixture of alloy steel powder, Ni powder, Cu powder, and graphite powder, or after the lubricant is mixed with the iron-based mixed powder. The lubricant may be added by heating and cooling to adhere the lubricant to the powder. A powder lubricant can also be added after deposition.
Further, in the attaching step, Ni powder, Cu powder and graphite powder may be attached using a lubricant as a binder. By doing in this way, segregation of Ni powder, Cu powder, and graphite powder can be prevented. Further, a powder lubricant can be added.
さらに、本発明の鉄基粉末混合物は、弱酸化性であるRXガス雰囲気中での1100〜1200℃の低温焼結を施しても、焼結のままでの 800 MPa以上の高強度を有する焼結体とすることができる。しかしながら、この条件に限定されるものではなく、N2,酸化性であるAXガス等他の雰囲気中で高温焼結を行うこともできることは言うまでもない。 Furthermore, the iron-based powder mixture of the present invention has a high strength of 800 MPa or more as it is sintered even when subjected to low-temperature sintering at 1100 to 1200 ° C. in a weakly oxidizing RX gas atmosphere. It can be a ligation. However, it is not limited to this condition, and it goes without saying that high-temperature sintering can be performed in other atmospheres such as N 2 and oxidizing AX gas.
Mo:1.0 質量%およびNi:2.1 質量%を含有し、残部はFeおよび不可避的不純物の組成になる溶鋼を溶製し、水アトマイズ法で粉体とした後、仕上還元処理を施して、予合金鋼粉とした。ついで、この予合金鋼粉に、Ni粉:2.0 質量%、Cu粉:1.5 質量%および黒鉛粉:0.6 質量%を混合したのち、表1に示す潤滑剤をV型ブレンダで添加混合した。
得られた鉄基粉末混合物を、日本粉末冶金工業会(JPMA )のM04-1992に準拠して、成形圧力:686 MPa で引張試験片形状に成形した。ついで、これらの成形体に、RXガス雰囲気中で、特に脱ろうのための保持はせずに、昇温速度:60℃/分、1130℃×20分、冷却速度:60℃/分の条件で焼結を施し、焼結体とした。焼結後、大気中にて 180℃、60分の焼戻し処理を施した。
かくして得られた焼結体の密度および引張強さについて調べた結果を、表1に併記する。
なお、焼結体の密度はJIS Z 2501、引張強さはJIS Z 2550に従い測定した。
Mo: 1.0% by mass and Ni: 2.1% by mass, the balance is made of molten steel with a composition of Fe and unavoidable impurities, and powdered by the water atomization method. Alloy steel powder was used. Next, Ni powder: 2.0 mass%, Cu powder: 1.5 mass%, and graphite powder: 0.6 mass% were mixed with the pre-alloyed steel powder, and then the lubricant shown in Table 1 was added and mixed with a V-type blender.
The obtained iron-based powder mixture was molded into a tensile test piece shape at a molding pressure of 686 MPa in accordance with M04-1992 of the Japan Powder Metallurgy Industry Association (JPMA). Next, these compacts were not held for dewaxing in an RX gas atmosphere, and the conditions were as follows: heating rate: 60 ° C./min, 1130 ° C. × 20 min, cooling rate: 60 ° C./min Was sintered to obtain a sintered body. After sintering, a tempering treatment was performed in the atmosphere at 180 ° C. for 60 minutes.
The results of examining the density and tensile strength of the sintered body thus obtained are also shown in Table 1.
The density of the sintered body was measured according to JIS Z 2501, and the tensile strength was measured according to JIS Z 2550.
同表に示したとおり、本発明に従い、潤滑剤として極圧添加剤を10質量%以上含有するものを用いた場合には、潤滑剤の添加量が0.5 質量%以下という少ない量で、引張強さが810 MPa 以上の高強度焼結体を得ることができた。 As shown in the table, according to the present invention, when a lubricant containing an extreme pressure additive of 10% by mass or more is used, the amount of lubricant added is as small as 0.5% by mass or less in tensile strength. A high-strength sintered body with a thickness of 810 MPa or more could be obtained.
表2に示す量のMo,Niを予合金化した合金溶鋼を溶製し、水アトマイズ法で粉体とした後、仕上還元処理を施して、予合金鋼粉とした。ついで、これらの予合金鋼粉に、表2に示す量のNi粉、Cu粉、黒鉛粉を混合し、さらに得られた鉄基混合粉:100 質量部に対し、潤滑剤として、極圧添加剤(ジブチルジチオカルバミン酸モリブデン):25質量%を含有し、残部は実質的にステアリン酸亜鉛からなる潤滑剤:0.4 質量部をV型ブレンダで添加混合した。
得られた鉄基粉末混合物を、実施例1と同様にして成形、焼結して得た焼結体の密度および引張強さについて調べた結果を、表2に併記する。
An alloy molten steel in which the amounts of Mo and Ni shown in Table 2 were pre-alloyed was melted and powdered by a water atomization method, and then subjected to a finish reduction treatment to obtain a pre-alloyed steel powder. Next, Ni powder, Cu powder, and graphite powder in the amounts shown in Table 2 were mixed with these pre-alloyed steel powders, and the resulting iron-based mixed powder: 100 parts by mass was added to the extreme pressure as a lubricant. Agent (molybdenum dibutyldithiocarbamate): 25 parts by mass, with the balance being substantially composed of zinc stearate: 0.4 parts by mass of a lubricant was added and mixed in a V-type blender.
Table 2 shows the results of examining the density and tensile strength of the sintered body obtained by molding and sintering the obtained iron-based powder mixture in the same manner as in Example 1.
同表から明らかなように、Mo,Niの予合金化率およびNi粉、Cu粉および黒鉛粉の混合割合が本発明の好適範囲を満足する鉄基粉末混合物を用いた場合にはいずれも、焼結体密度が 7.08 Mg/m以上、引張強さが 840 MPa以上という高強度焼結体を得ることができた。
これに対し、No.1, 5, 9, 14, 18の比較例はそれぞれ、合金鋼粉中のMo、Ni量、Ni粉量、Cu粉量、黒鉛粉量が少なく、強度向上の効果が小さいため、高強度焼結体が得られていない。
また、No.4, 8 はそれぞれ、Mo, Ni量が多すぎ、鋼粉粒子が硬化するため、焼結体密度が著しく低下し、高強度が得られていない。No.13 は、Ni粉量が多すぎ、残留オーステナイトが著しく多くなるため、高強度が得らていない。No.17 は、Cu粉量が多すぎるため、高強度が得られていない。
As is clear from the table, when using an iron-based powder mixture in which the prealloying rate of Mo and Ni and the mixing ratio of Ni powder, Cu powder and graphite powder satisfy the preferred range of the present invention, A high-strength sintered body with a sintered body density of 7.08 Mg / m or more and a tensile strength of 840 MPa or more was obtained.
On the other hand, the comparative examples of No. 1, 5, 9, 14, and 18 each had less Mo, Ni, Ni powder, Cu powder, and graphite powder in the alloy steel powder, and had the effect of improving strength. Since it is small, a high-strength sintered body has not been obtained.
In Nos. 4 and 8, the amounts of Mo and Ni are too large and the steel powder particles are hardened, so that the density of the sintered body is remarkably lowered and high strength is not obtained. No. 13 does not have high strength because the amount of Ni powder is too much and the retained austenite is remarkably increased. No.17 has not obtained high strength because the amount of Cu powder is too much.
Claims (1)
Iron-based mixed powder in which Ni powder, Cu powder and graphite powder are mixed with alloy steel powder prealloyed with Ni and Mo: 100 parts by mass, organohalogen compound, organosulfur compound, organophosphorus compound and organometallic compound A lubricant containing at least 10% by mass of at least one selected from among these is added in a proportion of 0.05 to 0.5 parts by mass, and the prealloying rate of Ni and Mo in the alloy steel powder is Ni: 0.5 to 3% by mass. %, Mo: more than 0.7 to 4% by mass, and the mixing ratio of Ni powder, Cu powder and graphite powder in the iron-based mixture is Ni powder: 0.5-5% by mass, Cu powder: 0.5-3% by mass, graphite powder : 0.2 to 1.0% by mass An iron-based powder mixture for high-strength sintered parts.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2004007533A JP4367133B2 (en) | 2004-01-15 | 2004-01-15 | Iron-based powder mixture for high-strength sintered parts |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2004007533A JP4367133B2 (en) | 2004-01-15 | 2004-01-15 | Iron-based powder mixture for high-strength sintered parts |
Publications (2)
Publication Number | Publication Date |
---|---|
JP2005200698A true JP2005200698A (en) | 2005-07-28 |
JP4367133B2 JP4367133B2 (en) | 2009-11-18 |
Family
ID=34821134
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP2004007533A Expired - Fee Related JP4367133B2 (en) | 2004-01-15 | 2004-01-15 | Iron-based powder mixture for high-strength sintered parts |
Country Status (1)
Country | Link |
---|---|
JP (1) | JP4367133B2 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2013053358A (en) * | 2011-09-06 | 2013-03-21 | Sumitomo Electric Sintered Alloy Ltd | Method of producing sintered component |
JP2015124408A (en) * | 2013-12-26 | 2015-07-06 | 株式会社神戸製鋼所 | Soft magnetic powder |
JP2018123383A (en) * | 2017-02-02 | 2018-08-09 | 株式会社神戸製鋼所 | Mixed powder for powder metallurgy |
-
2004
- 2004-01-15 JP JP2004007533A patent/JP4367133B2/en not_active Expired - Fee Related
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2013053358A (en) * | 2011-09-06 | 2013-03-21 | Sumitomo Electric Sintered Alloy Ltd | Method of producing sintered component |
JP2015124408A (en) * | 2013-12-26 | 2015-07-06 | 株式会社神戸製鋼所 | Soft magnetic powder |
JP2018123383A (en) * | 2017-02-02 | 2018-08-09 | 株式会社神戸製鋼所 | Mixed powder for powder metallurgy |
Also Published As
Publication number | Publication date |
---|---|
JP4367133B2 (en) | 2009-11-18 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
Narasimhan | Sintering of powder mixtures and the growth of ferrous powder metallurgy | |
JP5992402B2 (en) | Manufacturing method of nitrided sintered component | |
JP5308123B2 (en) | High-strength composition iron powder and sintered parts using it | |
JP2005530037A (en) | Prealloy iron-based powder and method for producing one or more sintered parts | |
EP1768803A1 (en) | Stainless steel powder | |
JP2014181381A (en) | Iron-based sintered sliding member and production method thereof | |
JP2014177658A (en) | Iron-based sintered sliding member and production method thereof | |
JP2011094187A (en) | Method for producing high strength iron based sintered compact | |
JP4201830B2 (en) | Iron-based powder containing chromium, molybdenum and manganese and method for producing sintered body | |
JP5125158B2 (en) | Alloy steel powder for powder metallurgy | |
JP6528899B2 (en) | Method of manufacturing mixed powder and sintered body for powder metallurgy | |
JP4367133B2 (en) | Iron-based powder mixture for high-strength sintered parts | |
JP2006241533A (en) | Iron based mixed powder for high strength sintered component | |
JP2009263697A (en) | Method for manufacturing sintered steel | |
KR100978901B1 (en) | MANUFACTURING METHOD OF Fe-BASED SINTERED BODY WITH HIGH TENSILE STRENGTH AND HIGH HARDNESS | |
JPH01259103A (en) | Method for sintering fe-c-cu series multi-component alloy powder | |
JP6384687B2 (en) | Manufacturing method of iron-based sintered sliding member | |
JP6519955B2 (en) | Iron-based sintered sliding member and method of manufacturing the same | |
US6652618B1 (en) | Iron based mixed power high strength sintered parts | |
JP4839271B2 (en) | Mixed powder for powder metallurgy and sintered iron powder | |
JP4013395B2 (en) | Iron-based mixed powder for high-strength sintered parts | |
JPH0959740A (en) | Powder mixture for powder metallurgy and its sintered compact | |
JP6627856B2 (en) | Method for producing powder mixture for powder metallurgy and sintered body | |
JP3303026B2 (en) | High strength iron-based sintered alloy and method for producing the same | |
US10843269B2 (en) | Method of producing sintered and forged member |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20061026 |
|
A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20070831 |
|
A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20070911 |
|
A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20071107 |
|
RD03 | Notification of appointment of power of attorney |
Free format text: JAPANESE INTERMEDIATE CODE: A7423 Effective date: 20071107 |
|
A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20080603 |
|
A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20080729 |
|
A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20090106 |
|
A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20090305 |
|
TRDD | Decision of grant or rejection written | ||
A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20090804 |
|
A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 |
|
A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20090817 |
|
R150 | Certificate of patent (=grant) or registration of utility model |
Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120904 Year of fee payment: 3 |
|
FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120904 Year of fee payment: 3 |
|
FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130904 Year of fee payment: 4 |
|
LAPS | Cancellation because of no payment of annual fees |