JP3449110B2 - Iron-based mixed powder for powder metallurgy and method for producing sintered body using the same - Google Patents
Iron-based mixed powder for powder metallurgy and method for producing sintered body using the sameInfo
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- JP3449110B2 JP3449110B2 JP09564996A JP9564996A JP3449110B2 JP 3449110 B2 JP3449110 B2 JP 3449110B2 JP 09564996 A JP09564996 A JP 09564996A JP 9564996 A JP9564996 A JP 9564996A JP 3449110 B2 JP3449110 B2 JP 3449110B2
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- powder
- iron
- sintering
- based mixed
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Description
【0001】[0001]
【発明の属する技術分野】本発明は、焼結体の強度を損
なうことなく、焼結時における寸法変化率の調整が容易
であり、しかも、旋削およびドリル穿孔のいずれにおい
ても、また高速切削および低速切削のいずれにおいても
優れた被削性を備えた焼結体を与える粉末冶金用鉄系粉
末、およびこれを用いた焼結体の製法に関するものであ
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention makes it easy to adjust the dimensional change rate during sintering without impairing the strength of the sintered body, and further, in both turning and drilling, high-speed cutting and The present invention relates to an iron-based powder for powder metallurgy which gives a sintered body having excellent machinability in any of low-speed cutting, and a method for producing a sintered body using the same.
【0002】[0002]
【従来の技術】粉末冶金は様々の機械部品の工業的生産
方法として有望な技術であり、広く用いられているが、
現実には金型を使ったプレス成形の制約上、多くの場合
焼結部品には最終的に何らかの機械加工が施されてい
る。従って、焼結後の機械加工をより簡素化するには、
焼結時の寸法変化率制御性を高めることによって機械加
工量をできるだけ少なく抑えることが望ましいが、こう
した観点からの具体的な改良研究はあまり行なわれてい
ない。また焼結部品は、同一組成の溶製材に比べて被削
性が悪いことも確認されており、この原因としては、焼
結体中に存在する空孔が熱伝導による熱放散を阻害して
切削加工部の温度を高めること、および切削工具に断続
的な衝撃を与えることが指摘されている。2. Description of the Related Art Powder metallurgy is a promising technology as an industrial production method for various machine parts and is widely used.
In reality, in most cases, the sintered parts are finally subjected to some machining due to the constraints of press molding using a mold. Therefore, to further simplify machining after sintering,
It is desirable to suppress the amount of machining as much as possible by enhancing the controllability of the dimensional change rate during sintering, but concrete improvement studies from this point of view have not been conducted so much. It has also been confirmed that the machinability of sintered parts is poorer than that of ingots of the same composition. The cause is that the pores present in the sintered body impede heat dissipation due to heat conduction. It has been pointed out that the temperature of the cutting part is increased and the cutting tool is subjected to intermittent impact.
【0003】そこで焼結材料の被削性を改善するため、
従来より粉末冶金用鉄系粉末に、C(黒鉛)粉その他の
物性改善用合金元素粉末と共にMnS粉末を含有させ、
焼結体の被削性を高める方法が採用されている。MnS
粉末を含有させることによってもたらされる被削性改善
効果は、MnSによる切削チップのフレーク化が促進さ
れるためと考えられている。Therefore, in order to improve the machinability of the sintered material,
Conventionally, MnS powder has been added to iron-based powder for powder metallurgy together with C (graphite) powder and other alloying element powder for improving physical properties,
A method of improving the machinability of the sintered body is adopted. MnS
It is considered that the machinability improving effect brought about by containing the powder is that flaking of the cutting tip is promoted by MnS.
【0004】また他の被削性改善法として、たとえば特
開昭63−93483号公報には、原料粉末中にガラス
や窒化硼素、タルク等を混合する方法、特開平7−33
78号公報にはセピオライト、アタプルジャイト、ゼオ
ライト等を添加する方法、更には、「精密工学会誌」V
ol.61,No.2,p238〜242(1995)
には、被削性改善成分としてゲーレナイト粉末とMnS
粉末を複合添加する方法が開示されている。これらの従
来技術において、ゲーレナイト等の複合酸化物によって
被削性改善効果が得られる理由は、それらの複合酸化物
が切削加工熱によって溶融し、切削工具の加工面に保護
被膜を形成するためと考えられている。ところが本発明
者らが追試確認したところによると、複合酸化物を利用
する従来の被削性改善法では、必ずしも満足のいく改質
効果を安定して得ることはできなかった。As another machinability improving method, for example, Japanese Patent Laid-Open No. 63-93483 discloses a method of mixing glass, boron nitride, talc, etc. in a raw material powder, and Japanese Patent Laid-Open No. 7-33.
No. 78 discloses a method of adding sepiolite, attapulgite, zeolite, etc., and further, "Journal of Precision Engineering" V
ol. 61, No. 2, p238-242 (1995)
Include, as a machinability improving component, a grenite powder and MnS.
A method for multiple addition of powders is disclosed. In these conventional techniques, the reason why the machinability improving effect is obtained by the complex oxide such as gehlenite is that these complex oxides are melted by the cutting heat and form a protective coating on the machined surface of the cutting tool. It is considered. However, according to the additional tests confirmed by the present inventors, the conventional machinability improving method using a complex oxide cannot always stably obtain a satisfactory modifying effect.
【0005】[0005]
【発明が解決しようとする課題】本発明は上記の様な従
来技術に着目してなされたものであって、その目的は、
焼結時における寸法変化率制御性が良好であると共に、
優れた機械的特性(強度や疲労特性等)を有し且つ安定
して優れた被削性を有する焼結品を与える粉末冶金用鉄
系混合粉末を提供しようとするものである。SUMMARY OF THE INVENTION The present invention has been made by paying attention to the above-mentioned prior art, and its purpose is to:
Good dimensional change rate controllability during sintering,
It is intended to provide an iron-based mixed powder for powder metallurgy, which provides a sintered product having excellent mechanical properties (strength, fatigue properties, etc.) and having stable machinability.
【0006】[0006]
【課題を解決するための手段】上記課題を解決すること
のできた本発明に係る粉末冶金用鉄系混合粉末とは、鉄
粉を主体とし、アノールサイト相および/またはゲーレ
ナイト相を有する平均粒径50μm以下のCaO−Al
2 O3 −SiO2 系複合酸化物の粉末を0.02〜0.
3重量%含有するところにその特徴が存在する。この発
明においては、上記複合酸化物として平均粒子径が12
μm以下であるものを使用することによって、改質効果
を一層確実且つ安定して発揮させることができる。The iron-based mixed powder for powder metallurgy according to the present invention, which has been able to solve the above-mentioned problems, is mainly composed of iron powder and has an average particle size having an anorthite phase and / or a grenite phase. CaO-Al of 50 μm or less
The powder of the 2 O 3 —SiO 2 -based composite oxide was added to 0.02 to 0.
Its characteristic is that it contains 3% by weight. In the present invention, the composite oxide has an average particle size of 12
By using those having a thickness of not more than μm, the modifying effect can be exhibited more reliably and stably.
【0007】また、上記で使用する鉄粉として、S含有
量が0.15〜0.5重量%で、Mn含有量が、該S量
に対し化学当量のMn量+0.3重量%以下であるSと
Mnを固溶状態で含有する鉄粉を使用し、あるいは、他
の成分として平均粒子径65μm以下のMnS粉末を
0.1〜0.7重量%含む混合粉末を使用すれば、焼結
体の被削性を一段と優れたものとすることができるので
好ましい。また本発明の上記混合粉末には、必要により
浸炭強化成分として適量のグラファイトを含有させ、あ
るいは要求特性に応じて適量の物性改善用金属粉末を含
有させることによって、焼結品の物性改善を図ることが
でき、更には、圧粉成形時の圧密度の向上を期してワッ
クスや金属石けん等の潤滑剤を添加し、あるいは上記の
様な添加材の均一分散を促進する為、軽油、油脂、SB
R等のゴム、多価アルコール脂肪酸エステル等の偏析防
止剤を添加することも有効である。Further, as the iron powder used above, the S content is 0.15 to 0.5% by weight, and the Mn content is the chemical equivalent of the Mn amount + 0.3% by weight or less. If iron powder containing a certain S and Mn in a solid solution state is used, or if a mixed powder containing 0.1 to 0.7% by weight of MnS powder having an average particle size of 65 μm or less is used as another component, the firing It is preferable because the machinability of the bonded body can be further improved. Further, if necessary, the above-mentioned mixed powder of the present invention contains an appropriate amount of graphite as a carburizing-strengthening component, or an appropriate amount of a metal powder for improving physical properties in accordance with required characteristics to improve the physical properties of a sintered product. Furthermore, in order to improve the compaction density during compaction molding, a lubricant such as wax or metal soap is added, or in order to promote uniform dispersion of the additive as described above, light oil, oil and fat, SB
It is also effective to add a rubber such as R and a segregation preventing agent such as a polyhydric alcohol fatty acid ester.
【0008】また本発明に係る焼結体の製法とは、上記
の様な粉末冶金用混合粉末を圧粉成形し、650〜15
00℃で焼結するところに特徴を有するものであり、こ
うした焼結温度を特定することによって、上記粉末冶金
用鉄系混合粉末の特徴を有効に活かし、優れた寸法変化
率制御性の下で、強度や被削性に優れた焼結体を得るこ
とが可能となる。The method for producing a sintered body according to the present invention means that the mixed powder for powder metallurgy as described above is compacted to form 650 to 15
It has a characteristic that it is sintered at 00 ° C. By specifying such a sintering temperature, the characteristics of the above iron-based mixed powder for powder metallurgy are effectively utilized, and under excellent dimensional change rate controllability. It is possible to obtain a sintered body having excellent strength and machinability.
【0009】[0009]
【発明の実施の形態】まず本発明で用いられる粉末冶金
用鉄系粉末としては、還元鉄粉(鉱石還元鉄粉、ミルス
ケール還元鉄粉、海綿鉄粉等を総称する)、アトマイズ
鉄粉、電解鉄粉など一般的に使用されるものでよく、特
に限定されないが、SiO2 の様な被削性を阻害する硬
質酸化物系不純物の含有量は少ないものが望ましい。ま
た本発明者らが鉄粉中に含まれるMnの存在形態やその
含有量の影響について検討を行ったところによると、M
n含有量は、硫黄や酸素と結合しないで存在する場合に
は強度の低下を招かない範囲で少ない方が好ましいこと
を確認している。BEST MODE FOR CARRYING OUT THE INVENTION First, as the iron-based powder for powder metallurgy used in the present invention, reduced iron powder (collectively referred to as ore reduced iron powder, mill scale reduced iron powder, sponge iron powder, etc.), atomized iron powder, It may be a commonly used one such as electrolytic iron powder and is not particularly limited, but it is desirable that the content of hard oxide impurities such as SiO 2 that inhibits machinability is small. In addition, the present inventors have examined the existence form of Mn contained in the iron powder and the influence of the content thereof.
It has been confirmed that the n content is preferably as small as possible within the range in which the strength is not deteriorated when the n content is present without binding with sulfur or oxygen.
【0010】ゲーレナイトの添加による旋削性向上効果
については、前記「精密工学会誌」に示唆されており、
ゲーレナイトの添加は寸法変化率の変化や強度劣化を起
こすことがなく、場合によっては抗折力の向上にも寄与
し得ることを明らかにしている。ところが、本発明者ら
が実際に追試実験を行なったところでは、期待される様
な被削性改善効果を得ることはできなかった。The effect of improving the turning property by the addition of gehlenite is suggested in the above "Journal of Precision Engineering",
It has been clarified that the addition of gehlenite does not cause a change in the dimensional change rate or strength deterioration and may contribute to the improvement of the transverse rupture strength in some cases. However, when the present inventors actually conducted a follow-up test, the expected machinability improvement effect could not be obtained.
【0011】そこで本発明者らは、ゲーレナイト(Ge
hlenite,2CaO・Al2O3 ・SiO2 )相
を有するCaO−Al2 O3 −SiO2 系複合酸化物の
粉末(以下、再びゲーレナイト粉末という)、およびこ
れよりも更に融解温度が低く、複合酸化物系保護被膜形
成成分として有効に作用すると考えられるアノールサイ
ト(Anorthite,CaO・Al2 O3 ・2Si
O2 )相を有するCaO−Al2 O3 −SiO2 系複合
酸化物(以下、アノールサイト粉末という)に注目し、
その特徴を実用規模でより有効に活用可能にすべく、そ
れらの粉末粒度、添加量、焼結温度と焼結時における寸
法変化挙動、焼結体やその熱処理体の強度および被削性
について詳細な検討を行った。Therefore, the present inventors have found that Gerenite (Ge)
Hlenite, powder CaO-Al 2 O 3 -SiO 2 composite oxide having a 2CaO · Al 2 O 3 · SiO 2) phase (hereinafter again called gehlenite powder), and which further melting temperature is lower than the composite Anorthite (CaO.Al 2 O 3 .2Si), which is considered to act effectively as an oxide-based protective film forming component
O 2) phase CaO-Al 2 O 3 -SiO 2 composite oxide having a (hereinafter, focused on) that anole site powder,
In order to make more effective use of its characteristics on a practical scale, details of the powder particle size, addition amount, sintering temperature and dimensional change behavior during sintering, strength and machinability of the sintered body and its heat-treated body are detailed. I examined it.
【0012】その結果、ゲーレナイト粉末やアノールサ
イト粉末の添加は、焼結工程における寸法変化挙動に明
確な変化をもたらすことを知った。即ち、粉末冶金用鉄
系混合粉末中に配合されるゲーレナイト粉末やアノール
サイト粉末の量を多くするにつれて、焼結時の800〜
950℃前後で生じる見掛けのα→γ変態完了点が高温
側へ移行し、且つα→γ変態完了時点の寸法変化率(膨
張量)が小さくなるのである。更に一般の鉄系粉末は、
1000〜1300℃で行なわれる通常の均熱保持によ
り、鉄粉粒子同士の焼結が進行して収縮を起こすが、原
料粉末中にゲーレナイト粉末やアノールサイト粉末を含
有させると、この時の収縮量も変わってくることが確認
された。即ちゲーレナイト粉末やアノールサイト粉末を
含有させると、鉄粉と副原料(グラファイトや物性改善
用金属粉末など)の種類や配合量あるいは焼結法等にも
よるが、最終的に得られる焼結体の寸法に少なからぬ影
響を与えるのである。As a result, it has been found that the addition of the grenite powder and the anolsite powder causes a clear change in the dimensional change behavior in the sintering process. That is, as the amount of the grenenite powder or the anorthite powder mixed in the iron-based mixed powder for powder metallurgy increases,
The apparent α → γ transformation completion point that occurs at around 950 ° C. shifts to the high temperature side, and the dimensional change rate (expansion amount) at the time of the α → γ transformation completion is reduced. Further general iron-based powder,
By the normal soaking and holding performed at 1000 to 1300 ° C., the sintering of the iron powder particles progresses to cause shrinkage, but when the raw material powder contains the grenite powder or the anolsite powder, the shrinkage amount at this time Was confirmed to change. That is, when a grenenite powder or an anorthite powder is contained, the final sintered body can be obtained depending on the type and blending amount of iron powder and auxiliary materials (graphite, metal powder for improving physical properties, etc.) or the sintering method. It has a considerable effect on the dimensions of.
【0013】そこで本発明者らは、ゲーレナイト粉末や
アノールサイト粉末が焼結時の寸法変化挙動に与える影
響について検討した結果、次の様な事実を知った。即ち
ゲーレナイトおよびアノールサイトに含まれるSiは炭
化物を形成し易い元素であるため、一般に浸炭強化成分
として配合されるC(グラファイト粉末として配合され
る)が鉄内へ拡散・固溶していくのを遅らせ、見掛けの
α→γ変態完了温度が高温側へシフトすること、ゲーレ
ナイト粉末やアノールサイト粉末を多量に含有させる
と、鉄粉の粒子間にゲーレナイト粉末やアノールサイト
粉末が存在する確率が高くなり、均熱保持中の鉄粉同士
の焼結による収縮量が小さくなること、更には均熱保持
終了後の冷却過程においても、Feに比べて熱膨張係数
の小さなゲーレナイト粉末やアノールサイト粉末が鉄系
粉末の間に介在すると、冷却時の収縮量が小さくなって
最終的に膨張傾向を示す様になる。Then, the present inventors have studied the effect of the gerenite powder and the anolsite powder on the dimensional change behavior during sintering, and as a result, have found the following facts. That is, since Si contained in gehrenite and anorthite is an element that easily forms a carbide, C (generally blended as a graphite powder), which is generally blended as a carburizing-strengthening component, diffuses into iron and forms a solid solution. Delaying, the apparent α → γ transformation completion temperature shifts to the high temperature side, and when a large amount of gehlenite powder or anorthite powder is included, the probability that there will be gehlenite powder or anorthite powder between the iron powder particles will increase. The shrinkage amount due to the sintering of the iron powders during the soaking is small, and even in the cooling process after the completion of the soaking, the grenenite powder or the anorthite powder has a smaller thermal expansion coefficient than that of Fe. If it is interposed between the system powders, the amount of shrinkage during cooling becomes small, and finally it tends to expand.
【0014】またゲーレナイト粉末やアノールサイト粉
末の粒径も、焼結時の寸法変化挙動や焼結体の強度、被
削性に顕著な影響を及ぼすことも確認された。即ち粉末
冶金用鉄系粉末中に被削性改善成分としてゲーレナイト
粉末やアノールサイト粉末を含有させた場合、それらの
粒径によっては、圧粉成形に際し鉄粉粒子間に生じる空
隙内へ充填されていく確率や鉄粉粒子間に存在する確率
がかなり変わってくるのである。It was also confirmed that the particle diameters of the grenite powder and the anolsite powder also significantly affect the dimensional change behavior during sintering, the strength of the sintered body, and the machinability. That is, when the iron-based powder for powder metallurgy contains a grenenite powder or an anorthite powder as a machinability improving component, depending on their particle size, it is filled in the voids generated between the iron powder particles during compaction molding. The probability of going and the probability of existing between iron powder particles will change considerably.
【0015】そこで、上記の様なゲーレナイト粉末およ
びアノールサイト粉末の挙動や焼結時の寸法変化に及ぼ
す影響等を考慮し、それら粉末の好ましい粒度構成や含
有量、MnS,グラファイト粉末その他副原料の粒径と
添加量、焼結温度とCの拡散、均熱保持による焼結体の
収縮量や冷却時の熱収縮などを含めて詳細な検討を重ね
た結果、以下に詳述する如く、鉄系混合粉末中に適正粒
度構成のゲーレナイト粉末および/またはアノールサイ
ト粉末を適量含有させてやれば、優れた寸法制御性のも
とで安定した強度特性を有すると共に、被削性が良好で
旋削性はもとよりドリルによる穿孔切削性にも優れ、且
つ高速切削はもとより低速切削に適用した場合でも優れ
た被削性を有する焼結体が得られることを知り、上記本
発明に想到した。Therefore, in consideration of the behavior of the above-mentioned grenite powder and anorthite powder and the influence on the dimensional change during sintering, the preferable grain size constitution and content of these powders, MnS, graphite powder and other auxiliary materials As a result of detailed examinations including grain size and addition amount, sintering temperature and diffusion of C, shrinkage amount of the sintered body due to soaking, heat shrinkage during cooling, etc. If a proper amount of Gerenite powder and / or anorthite powder with a proper particle size composition is included in the mixed powder, it has stable strength characteristics under excellent dimensional controllability, good machinability and turning property. The inventors of the present invention have come to the present invention by knowing that a sintered body having excellent machinability by drilling as well as high-speed cutting as well as high-speed cutting can be obtained.
【0016】以下、本発明で規定する前記各要件につい
て、夫々の設定理由を実験データに基づいて詳細に説明
していく。The reasons for setting each of the requirements defined in the present invention will be described in detail below based on experimental data.
【0017】[ゲーレナイト粉末およびアノールサイト
粉末の好適粒径]まず、ゲーレナイト粉末とアノールサ
イト粉末の平均粒径を50μm以下、より好ましくは1
0μm以下と規定した理由について明らかにする。C
a、Al、Siの各酸化物を、それぞれゲーレナイト
(Gehlenite,2CaO・Al2 O3 ・SiO
2 )およびアノールサイト(Anorthite,Ca
O・Al2 O3 ・2SiO2 )の組成となる様に配合
し、加熱溶融した後、冷却・粉砕してゲーレナイト粉末
およびアノールサイト粉末を製造した。このとき、粉砕
時間、篩い網の目開き、気流分級条件を調整することに
よって、平均粒径を2〜150μmに調整した。[Suitable Particle Sizes of Gerenite Powder and Anolsite Powder] First, the average particle size of the grenite powder and anolsite powder is 50 μm or less, and more preferably 1.
The reason for defining 0 μm or less will be clarified. C
The oxides of a, Al, and Si are respectively converted into Gehlenite (2CaO.Al 2 O 3 .SiO 2).
2 ) and anorthite (Ca)
O.Al 2 O 3 .2SiO 2 ) was mixed, heated and melted, and then cooled and crushed to produce a grenite powder and anorthite powder. At this time, the average particle size was adjusted to 2 to 150 μm by adjusting the crushing time, the opening of the sieving mesh, and the airflow classification conditions.
【0018】得られたゲーレナイト粉末およびアノール
サイト粉末を、市販のアトマイズ鋼粉(神戸製鋼所製、
商品名「アトメル300M」)、アトマイズ銅粉(福田
金属社製、商品名「CuAtG−200」)、黒鉛粉
(日本黒鉛社製、商品名「J−CPB」)および潤滑剤
と共に高速ミキサーで混合し、Fe−2重量%Cu−
0.8重量%グラファイト−0.1重量%(ゲーレナイ
トまたはアノールサイト)+0.75重量%潤滑剤(−
は内数、即ち内部含有率、+は外数、即ち外部添加率を
意味する)よりなる1トンの粉末冶金用鉄系混合粉末を
調製した。The obtained grenenite powder and anolsite powder were mixed with commercially available atomized steel powder (Kobe Steel,
Product name "Atmel 300M"), atomized copper powder (manufactured by Fukuda Metal Co., product name "CuAtG-200"), graphite powder (manufactured by Nippon Graphite Co., product name "J-CPB") and a lubricant with a high-speed mixer. Fe-2 wt% Cu-
0.8 wt% graphite-0.1 wt% (gerenite or anolsite) +0.75 wt% lubricant (-
Was used to prepare an iron-based mixed powder for powder metallurgy of 1 ton, and + means an external content, that is, an external content.
【0019】上記組成の混合粉末1トンを連続式成形プ
レスの原料ホッパーに投入し、外径64mm、内径24
mm、厚さ20mm、成形体密度7.0g/cm3 の圧
粉成形体を約2400個成形した。この成形体は、引き
続いてメッシュベルト式連続焼結炉へ送り、10%H2
−N2 の雰囲気下に1120℃×30minの条件で焼
結を行い、外径寸法変化率、圧環強さ(環状の焼結体に
押潰し方向の圧力を加えたときの耐圧強度)、P種超硬
チップ1個当たりの平均旋削可能時間とそのバラツキR
を調査した。旋削試験は、圧粉成形・焼結を行なった順
番に10個毎に1個をサンプリングし、これらを10個
ずつ重ねて治具に固定し、乾式で外周を旋削加工した。
尚、旋削条件は、周速V:200m/min,送りf:
0.01mm/rev,切り込みt:0.5mmとし、
超硬チップの寿命は、工具の逃げ面摩耗量が0.3mm
に達するまでの時間によって評価した。結果を表1に示
す。1 ton of the mixed powder having the above composition was charged into the raw material hopper of the continuous molding press, and the outer diameter was 64 mm and the inner diameter was 24.
mm, a thickness of 20 mm, and a compact density of 7.0 g / cm 3 about 2400 compacts were compacted. The compact was continuously sent to a mesh belt type continuous sintering furnace and 10% H 2
Sintering was performed in an atmosphere of -N 2 under the condition of 1120 ° C. for 30 min, and the outer diameter dimensional change rate, radial crushing strength (pressure resistance when a pressure in the crushing direction was applied to an annular sintered body), P Average turning time per piece of carbide tip and its variation R
investigated. In the turning test, one out of every 10 pieces was sampled in the order of compacting and sintering, 10 pieces were piled up and fixed to a jig, and the outer periphery was turned by a dry method.
The turning conditions are: peripheral speed V: 200 m / min, feed f:
0.01 mm / rev, cut t: 0.5 mm,
Carbide tip has a tool flank wear of 0.3 mm
It was evaluated by the time to reach. The results are shown in Table 1.
【0020】[0020]
【表1】 [Table 1]
【0021】表1からも明らかである様に、外径寸法変
化率のバラツキ、圧環強さ、旋削可能時間のバラツキを
いずれも高レベルに保つには、ゲーレナイト粉末および
アノールサイト粉末として平均粒径が50μm以下の粉
末を使用しなければならず、50μmを超える粗粒の粉
末を使用すると、いずれの値も極端に悪くなることを確
認できる。特に、平均粒径が10μm以下の微細粉を使
用すると、平均旋削可能時間が大幅に向上すると共に各
バラツキも非常に小さくなる。これは、ゲーレナイト粉
末およびアノールサイト粉末の鉄粉への均質分散性が向
上すると共に、切削加工時の工具とゲーレナイトまたは
アノールサイトとの接触確率も向上し、工具の表面保護
効果が有効に発揮されるためと思われる。As is clear from Table 1, in order to keep the variation of the outer diameter dimensional change rate, the radial crushing strength, and the variation of the lathe turning time at a high level, the average particle diameters of the grenenite powder and the anorthite powder are large. It must be used that the powder has a particle size of 50 μm or less, and it can be confirmed that all the values become extremely worse when a coarse powder having a particle size of more than 50 μm is used. In particular, when fine powder having an average particle size of 10 μm or less is used, the average turnable time is significantly improved and the variations are also significantly reduced. This improves homodispersibility of iron powder of gerenicite powder and anorthite powder, and also improves the contact probability between the tool and the grenite or anolsite during cutting, effectively exerting the surface protection effect of the tool. It seems to be because.
【0022】[有機結合剤および/または油脂による偏
析防止効果]本発明の粉末冶金用鉄系混合粉末には、主
体となる鉄粉および上記ゲーレナイト粉末および/また
はアノールサイト粉末の他、通常は浸炭強化成分として
グラファイトが含有され、更にはCu粉等の金属粉を含
有させることも多く、これらは比重、粒径等が様々であ
るので、ハンドリングやスクリューフィーダ等の粉体搬
送過程あるいは原料ホッパーからの供給過程で偏析を起
こし、焼結部品の特性にバラツキを生じる原因となる。[Segregation Preventing Effect of Organic Binder and / or Oil] In the iron-based mixed powder for powder metallurgy of the present invention, in addition to the main iron powder and the above-mentioned grenite powder and / or anorthite powder, usually carburizing is carried out. Graphite is contained as a reinforcing component, and moreover, metal powder such as Cu powder is often contained. Since these have various specific gravities, particle sizes, etc., they can be handled from a powder conveying process such as handling or a screw feeder or from a raw material hopper. Segregation occurs during the supply process, which causes variations in the characteristics of the sintered parts.
【0023】これらを防止する方法として、油脂、ある
いは特開平3−162502に示される様に脂肪酸と金
属石鹸の共溶融物等を配合し、鉄系粉末粒子表面に合金
粉末を固着する方法が知られている。そこで、本発明者
らはこうした技術を有効に活用するため、平均粒径9.
9μmのゲーレナイト粉末を用いた前記表1に示した発
明例3の混合粉末に対し、偏析防止剤を外部添加するこ
とによる偏析防止効果を調べた。As a method of preventing these, there is known a method of blending fats and oils or a co-melt of a fatty acid and a metal soap as shown in JP-A-3-162502 and fixing the alloy powder on the surface of the iron-based powder particles. Has been. Therefore, in order to effectively utilize such a technique, the present inventors have an average particle size of 9.
The anti-segregation effect of the external addition of the anti-segregation agent was investigated for the mixed powder of Invention Example 3 shown in Table 1 using 9 μm of a grenite powder.
【0024】結果は表2,3に示す通りであり、偏析防
止用の有機結合剤としてスチレン・ブタジエン・ラバー
(SBRと略記)を用いた場合は、その添加量が約0.
2%(以下、特記しない限り重量%を意味する)で旋削
可能時間バラツキの改善効果は飽和し、0.3%になる
と、成形体の強さの評価方法の一つであるラトラー値が
悪くなる傾向が生じてくる。従って、偏析防止剤として
SBRを使用する時の添加量は、0.2%程度以下に抑
えることが望ましい。こうした傾向は、偏析防止剤とし
てエチレン・グリコール・ジ・ステアレート(EGDS
と略記)を用いた場合もほぼ同様である。The results are shown in Tables 2 and 3. When styrene-butadiene rubber (abbreviated as SBR) was used as an organic binder for preventing segregation, the addition amount was about 0.
At 2% (hereinafter, unless otherwise specified, means% by weight), the effect of improving the variation in the turnable time saturates, and at 0.3%, the Ratler value, which is one of the evaluation methods of the strength of the molded body, is poor. There is a tendency to become. Therefore, when SBR is used as the segregation preventive agent, it is desirable to suppress the addition amount to about 0.2% or less. This tendency is due to ethylene glycol di-stearate (EGDS
And abbreviation) are used in the same manner.
【0025】一方軽油や脂肪酸を使用すると、旋削可能
時間のバラツキを低減する効果は見られるが、粉末を金
型へ充填する際の難易の尺度である流動性が、これらを
添加していない発明例3よりも悪くなる傾向が見られ、
従って軽油の場合は0.03%程度以下、脂肪酸の場合
は0.10%程度以下に抑えることが望ましい。On the other hand, when light oil or fatty acid is used, the effect of reducing the variation in the turnable time can be seen, but the fluidity, which is a measure of the difficulty when the powder is filled in the mold, does not include these. It tends to be worse than in Example 3,
Therefore, in the case of light oil, it is desirable to control the content to about 0.03% or less, and for the fatty acid, to control it to about 0.10% or less.
【0026】また、SBRと軽油または脂肪酸、EGD
Sと脂肪酸の併用によっても、それらの添加量を適正に
調整することによって、それらの添加効果を有効に発揮
させることができる。In addition, SBR and light oil or fatty acid, EGD
Even when S and fatty acids are used in combination, the effect of their addition can be effectively exerted by appropriately adjusting the addition amount thereof.
【0027】これらの実験からも明らかである様に、本
発明においても、有機結合剤や軽油、脂肪酸などの偏析
防止剤を添加することによって、旋削可能時間バラツキ
を低減せしめ、更には焼結材料の均質化によって平均旋
削可能時間も延長することが可能となる。As is apparent from these experiments, also in the present invention, the addition of an organic binder, a segregation preventing agent such as light oil, a fatty acid, etc., reduces the variation in the turnable time, and further, the sintered material. It is possible to extend the average turnable time by homogenizing.
【0028】[0028]
【表2】 [Table 2]
【0029】[0029]
【表3】 [Table 3]
【0030】[ゲーレナイト粉末およびアノールサイト
粉末の好適含有率]この実験では、混合粉末中に占める
ゲーレナイト粉末および/またはアノールサイト粉末の
含有率を0.02〜0.3%に規定した根拠を明らかに
する。市販の0.5%Ni−1.0%Moプレアロイ型
アトマイズ鋼粉(神戸製鋼所製、商品名「46F4
H」)を主体とし、グラファイト粉末含有率を0.6
%、ゲーレナイト粉末またはアノールサイト粉末の含有
量を0〜0.5%の範囲で変更した混合粉末を調製し、
それらを用いて前記と同様にしてリング状圧粉成形体の
成形および焼結を行ない、更に前記と同様にして旋削試
験および圧環強度試験を行なった。なお、旋削試験は焼
結後に行い、圧環強さは焼結後と、熱処理(光輝焼入・
焼戻し)後の夫々について測定した。[Preferable Content of Gerenite Powder and Anolsite Powder] In this experiment, the rationale for defining the content ratio of the grenite powder and / or the anolsite powder in the mixed powder to 0.02 to 0.3% is clarified. To Commercially available 0.5% Ni-1.0% Mo prealloyed atomized steel powder (Kobe Steel, trade name "46F4
H ”) as the main component, and the graphite powder content is 0.6
%, The content of the grenite powder or the anorthite powder was changed in the range of 0 to 0.5% to prepare a mixed powder,
Using these, a ring-shaped green compact was molded and sintered in the same manner as described above, and a turning test and a radial crushing strength test were performed in the same manner as described above. The turning test is performed after sintering, and the radial crushing strength is after sintering and heat treatment (bright quenching /
It measured about each after tempering.
【0031】結果は表4に示す通りであり、ゲーレナイ
ト粉末およびアノールサイト粉末の含有量が多くなるに
つれて、超硬チップ1個当たりの焼結体旋削可能時間は
長くなるが、含有量が0.01%では無添加材との間で
殆んど有意差が認められない。従ってその効果を有効に
活かすには、含有量を0.02%以上とすべきである。
一方、焼結体/熱処理体の圧環強さに着目すると、ゲー
レナイト粉末やアノールサイト粉末の含有率が0.07
%で圧環強さが最大となり、また焼結体では0.10%
を超え、熱処理体では0.3%を超えて過度に多く含有
させると、無添加材よりも強度は低下してくる。従っ
て、旋削時間と強度の両面から考えると、ゲーレナイト
/アノールサイト粉末の含有率は0.02〜0.3%の
範囲に設定すべきであることが分かる。The results are shown in Table 4, and as the contents of the gehlenite powder and the anorthite powder increased, the time during which the sintered body could be turned per one cemented carbide chip became longer, but the content was 0. At 01%, there is almost no significant difference with the additive-free material. Therefore, in order to effectively utilize the effect, the content should be 0.02% or more.
On the other hand, focusing on the radial crushing strength of the sintered body / heat-treated body, the content rate of the grenenite powder and the anolsite powder was 0.07.
%, The radial crushing strength becomes maximum, and 0.10% in the sintered body
And the heat-treated body exceeds 0.3% and is contained in an excessively large amount, the strength becomes lower than that of the additive-free material. Therefore, from the viewpoints of both turning time and strength, it can be seen that the content of the gehlenite / annolsite powder should be set in the range of 0.02 to 0.3%.
【0032】[0032]
【表4】 [Table 4]
【0033】[寸法変化率制御その1:ゲーレナイト粉
末および/またはアノールサイト粉末の添加量と焼結温
度の関係]この実験では、混合粉末中に占めるゲーレナ
イト粉末およびアノールサイト粉末の含有量が、焼結時
における寸法変化率に及ぼす影響について検討した。鉄
系粉末として、市販の4%Ni−1.5%Cu−0.5
%Mo部分拡散型の鋼粉(神戸製鋼所製、商品名「48
00DFC」)を使用し、グラファイト粉の含有率を
0.6%とすると共に、ゲーレナイト粉末またはアノー
ルサイト粉末の含有率を0〜1.0%の範囲で変えた供
試粉を調製し、これらの粉末を、前記と同様にして外径
64mm、内径24mm、厚さ10mmのリング状試験
片に圧粉成形した後、10%H2 −N2 雰囲気下に11
20℃×30minまたは1250℃×30minで焼
結を行い、金型基準の外径寸法変化率を調査した。[Control of Dimensional Change Rate 1: Relationship between Addition Amount of Gerenite Powder and / or Anorthite Powder and Sintering Temperature] In this experiment, the contents of the garenite powder and the anolsite powder in the mixed powder were the The influence on the dimensional change rate at the time of setting was examined. As iron-based powder, commercially available 4% Ni-1.5% Cu-0.5
% Mo partially diffused steel powder (Kobe Steel, trade name "48
00DFC ”) was used to prepare a test powder in which the content of graphite powder was 0.6% and the content of gerenite powder or anorthite powder was varied in the range of 0 to 1.0%. Was powder molded into a ring-shaped test piece having an outer diameter of 64 mm, an inner diameter of 24 mm, and a thickness of 10 mm in the same manner as described above, and then was subjected to 11% in a 10% H 2 —N 2 atmosphere.
Sintering was carried out at 20 ° C. × 30 min or 1250 ° C. × 30 min, and the mold-based outer diameter dimensional change rate was investigated.
【0034】結果は図1〜4に示す通りであり、112
0℃で焼結を行なった場合でも、ゲーレナイト粉末また
はアノールサイト粉末を微量添加すると、同一成形体密
度における外径寸法変化率は収縮(−)傾向を示し、含
有率が約0.05〜0.1%で収縮量は極大となる。そ
れ以降、含有率が多くなるにつれて次第に外径寸法変化
率は膨張傾向を示す様になる。The results are shown in FIGS.
Even when sintering is performed at 0 ° C., when a small amount of the grenenite powder or the anolsite powder is added, the outer diameter dimensional change rate in the same compact density shows a shrinkage (−) tendency, and the content rate is about 0.05 to 0. The shrinkage amount becomes maximum at 0.1%. After that, the dimensional change rate of the outer diameter gradually shows an expansion tendency as the content rate increases.
【0035】これらの傾向を基に、例えばゲーレナイト
粉末を含有させた混合粉末を用いて1120℃で焼結を
行う場合を考えると、ゲーレナイト粉末の含有量を約
0.18%程度とすることにより、無添加材とほぼ同じ
寸法変化率を得ることができる。そのため、専用の金型
を使用しなくとも、ゲーレナイト粉末含有による被削性
改善効果を有効に活用すること可能となる。On the basis of these tendencies, considering the case where sintering is performed at 1120 ° C. using a mixed powder containing a grenite powder, for example, by setting the content of the grenite powder to about 0.18%, It is possible to obtain almost the same dimensional change rate as the additive-free material. Therefore, it becomes possible to effectively utilize the machinability improving effect by containing the gehlenite powder without using a dedicated mold.
【0036】また、同一量のゲーレナイト粉末やアノー
ルサイト粉末を含有させた場合であっても、焼結温度に
より寸法変化率への影響の程度は若干異なってくる。即
ち、ゲーレナイト粉末および/またはアノールサイト粉
末を含有させた本発明の混合粉末では、先に述べた様に
無添加材に比して圧環強さが向上するので、無添加材よ
りも強度を低下させることなく、焼結温度を微調整して
寸法変化率を合わせることも可能となる。Further, even when the same amount of gerenic powder or anorthite powder is contained, the degree of influence on the dimensional change rate is slightly different depending on the sintering temperature. That is, in the mixed powder of the present invention containing the grenite powder and / or anorthite powder, as described above, the radial crushing strength is improved as compared with the additive-free material, so the strength is lower than that of the additive-free material. Without this, the sintering temperature can be finely adjusted to match the dimensional change rate.
【0037】例えば図5は、ゲーレナイト粉末0.3%
添加および無添加の混合粉末について、焼結温度と外径
寸法変化率の関係を示したグラフであり、この図からも
明らかである様に、ゲーレナイト粉末無添加の混合粉末
を用いた圧粉成形体を1250℃で焼結する場合と同様
の寸法変化率を、ゲーレナイト粉末含有率が0.3%の
混合粉末によって得ようとすれば、焼結温度を1230
℃とすれば良く、それにより、無添加材を1250℃で
焼結したものと同等の熱処理体強度と寸法変化率を得る
ことができる。For example, FIG. 5 shows 0.3% of grenite powder.
FIG. 3 is a graph showing the relationship between the sintering temperature and the outer diameter dimensional change rate of mixed powders with and without addition, and as is clear from this figure, compaction molding using mixed powders without addition of gerenite powder If a dimensional change rate similar to that in the case of sintering a body at 1250 ° C. is to be obtained with a mixed powder having a content rate of 0.3% of grenite powder, the sintering temperature is 1230.
It is sufficient to set the temperature to ℃, and thereby, it is possible to obtain the heat-treated body strength and the dimensional change rate equivalent to those obtained by sintering the additive-free material at 1250 ℃.
【0038】[寸法変化率制御その2:寸法変化率変動
のメカニズム]前記図1〜4では、ゲーレナイト粉末お
よびアノールサイト粉末の含有量が焼結時の寸法変化率
(DC)に及ぼす影響について明らかにしたが、寸法変
化率に影響を及ぼす原因を更に明確にするため、ディラ
トメータ(熱膨張計)を用いて検討を行った。[Control of Dimensional Change Rate 2: Mechanism of Variation in Dimensional Change Rate] In FIGS. 1 to 4 described above, the influence of the contents of the gerenic powder and the anorthite powder on the dimensional change rate (DC) during sintering is clarified. However, in order to further clarify the cause that affects the dimensional change rate, a dilatometer (thermal expansion meter) was used for the study.
【0039】その結果、図6,7に示す様に、ゲーレナ
イト粉末、アノールサイト粉末のいずれも、800〜9
50℃前後に見られる見掛けのα→γ変態完了点を高温
側に移動させ、かつα→γ変態完了時の膨張量を小さく
する作用が見られる。これは、アノールサイトおよびゲ
ーレナイトに含まれるSiが炭化物を形成し易い元素で
あるため、混合粉末中に含まれるグラファイト粉末由来
のCの鉄粉中への固溶を遅らせ、見掛けのα→γ変態完
了が高温側にシフトするためと考えられる。As a result, as shown in FIGS. 6 and 7, both the grenenite powder and the anorthite powder were 800 to 9
The effect is to move the apparent α → γ transformation completion point seen around 50 ° C. to the high temperature side and to reduce the expansion amount at the completion of α → γ transformation. This is because Si contained in anorthite and gehlenite is an element that easily forms a carbide, so that the solid solution of C derived from the graphite powder contained in the mixed powder into the iron powder is delayed, and the apparent α → γ transformation occurs. It is considered that the completion shifts to the high temperature side.
【0040】また均熱保持(図6,7では1250℃保
持)中の収縮量も、ゲーレナイト粉末あるいはアノール
サイト粉末を含有させることによって影響を受ける。即
ち、ゲーレナイト粉末やアノールサイト粉末の微量含有
では、無添加材よりも均熱保持中の収縮量が大きくなっ
ているのに対し、多量に含有させると、鉄粉粒子間に、
鉄粉と反応しないゲーレナイト粉末やアノールサイト粉
末が入り込み、焼結による収縮を阻害している様であ
り、これらのことがゲーレナイト粉末やアノールサイト
粉末の含有率によって、焼結体の寸法変化率が変動する
主たる原因と考えられる。そしてその影響の程度は、焼
結温度や配合組成によって変わってくる(前記図1〜
4,6,7参照)。Further, the amount of shrinkage during soaking (holding at 1250 ° C. in FIGS. 6 and 7) is also affected by the inclusion of the gehlenite powder or the anolsite powder. That is, in a small amount of the grenite powder and anorthite powder contained, the amount of shrinkage during soaking is larger than that of the additive-free material, whereas when contained in a large amount, between the iron powder particles,
It seems that gerenite powder and anorthite powder that do not react with iron powder enter and inhibit the shrinkage due to sintering.Thus, the dimensional change rate of the sintered body depends on the content ratio of the gerenite powder and anorthite powder. It is considered to be the main cause of fluctuation. And the extent of the influence depends on the sintering temperature and the composition (see Fig. 1-Fig. 1).
4, 6, 7).
【0041】更に均熱保持終了後の冷却過程では、ゲー
レナイト粉末やアノールサイト粉末を多量含有させるこ
とによって収縮勾配は変わってくる。つまり、金属に比
べて熱膨張率の小さなゲーレナイト粉末やアノールサイ
ト粉末が鉄粉粒子間に多量に存在すると、焼結体全体の
熱膨張が抑えられるため、室温まで冷却したときの膨張
傾向がより強くなるものと考えられる。Further, in the cooling process after the completion of the soaking, the shrinkage gradient is changed by adding a large amount of the grenite powder and the anolsite powder. In other words, when a large amount of gerenic powder or anorthite powder having a smaller coefficient of thermal expansion than metal exists between the iron powder particles, the thermal expansion of the entire sintered body is suppressed, so that the expansion tendency when cooled to room temperature is more It is expected to become stronger.
【0042】[焼結温度の規定理由]次に、本発明の鉄
系混合粉末を用いた圧粉成形体を焼結する際の温度を6
50〜1500℃に規定した理由について述べる。一般
に、焼結温度が低いほど焼結の程度は緩やかとなり、得
られる焼結体の被削性は良好となる。しかしながら、焼
結が殆んど進行していない状態では、ハンドリングや切
削加工機械への被加工物(焼結体)の取り付け(キャッ
チング、マウント)の際に、被加工物に割れや欠け、変
形といった問題を生じる恐れがでてくる。[Reasons for Defining Sintering Temperature] Next, the temperature for sintering a green compact using the iron-based mixed powder of the present invention is 6
The reason for defining 50 to 1500 ° C will be described. Generally, the lower the sintering temperature, the more gradual the degree of sintering and the better the machinability of the obtained sintered body. However, in the state where sintering has hardly progressed, cracking, chipping, or deformation of the work piece during handling (attaching the work piece (sintered body) to the cutting machine (catching, mounting)) There is a fear that such problems will occur.
【0043】これに対し焼結温度を高くすると、焼結体
の強度は増加する反面、熱エネルギーコストの増加や被
削性の低下といった一般的に知られた問題が生じてくる
他、ゲーレナイト粉末やアノールサイト粉末を含有する
本発明の混合粉末では、たとえば図8の状態図に示す様
に、化学式から求められる理論的結合比から若干ずれた
部分が分解する可能性が生じてくる。これらの分解物
は、焼結体内で不純介在物として作用し被削性を悪化さ
せる。従って、この様な熱分解を抑えるには、焼結温度
を1500℃以下に抑えることが必要となる。On the other hand, when the sintering temperature is increased, the strength of the sintered body is increased, but generally known problems such as an increase in thermal energy cost and a decrease in machinability are caused, and the grenite powder is produced. In the mixed powder of the present invention containing the oranol site powder, for example, as shown in the state diagram of FIG. 8, there is a possibility that a portion slightly deviated from the theoretical bond ratio obtained from the chemical formula may be decomposed. These decomposed products act as impure inclusions in the sintered body and deteriorate machinability. Therefore, in order to suppress such thermal decomposition, it is necessary to suppress the sintering temperature to 1500 ° C. or lower.
【0044】ちなみに下記表5は、市販の0.5%Ni
−1.0%Moプレアロイ型アトマイズ鋼粉(神戸製鋼
所製、商品名「46F4H」)を主体とし、グラファイ
ト粉末含有率が0.6%、ゲーレナイト粉末またはアノ
ールサイト粉末の含有量が0.1%である混合粉末を用
いて前記と同様にしリング状圧粉成形体を成形し、焼結
温度を種々変更したときの焼結体の損傷度合いを調べた
結果を示したものである。尚この実験では、圧粉成形し
た上記のリング状圧粉成形体を10個ずつ重ねて治具に
固定する際に、割れや欠け等を起こした供試材の数(1
000個当たりの個数)で評価した。この表からも明ら
かである様に、焼結体としての被削性を損なうことなく
十分な強度の焼結体を得るには、焼結温度を650〜1
500℃、好ましくは700〜1500℃の範囲に設定
すべきであることが分かる。By the way, Table 5 below shows commercially available 0.5% Ni.
-1.0% Mo prealloy type atomized steel powder (Kobe Steel Co., Ltd., trade name "46F4H") is the main component, the graphite powder content is 0.6%, the content of the grenite powder or anorthite powder is 0.1. The results of examining the degree of damage to the sintered body when the ring-shaped green compact was molded in the same manner as described above using the mixed powder (%) and the sintering temperature was variously changed are shown. In this experiment, the number of test materials (1) that were cracked or chipped when ten of the above-mentioned ring-shaped powder compacts that were compacted were stacked and fixed to a jig.
It was evaluated by the number per 000 pieces). As is clear from this table, in order to obtain a sintered body of sufficient strength without impairing the machinability of the sintered body, the sintering temperature should be 650 to 1
It is understood that the temperature should be set to 500 ° C, preferably 700 to 1500 ° C.
【0045】[0045]
【表5】 [Table 5]
【0046】[MnS粉末含有物との対比における、ゲ
ーレナイト粉末およびアノールサイト粉末含有による旋
削性改善効果]鉄粉−2%Cu−0.5%C(カーボ
ン)を基本組成とし、MnO,MnSとしての存在量は
ほぼ等しいが、MnおよびS含有率の異なる鉄粉を使用
すると共に、平均粒径15μmのゲーレナイト粉末また
はアノールサイト粉末を0.1%含有させた混合粉末を
使用し、前記と同様にして成形密度6.90g/cm3
の圧粉成形体を作製した。この成形体を1130℃×3
0分で焼結し、得られた焼結体について前記と同様にし
て被削性試験片を作製した。また、被削性改善用として
用いられている公知のMnS粉末添加材として、0.5
%のMnS粉末を含む鉄系粉末(三井金属社製)を用い
て同様に圧粉成形および焼結を行ない、被削性評価の基
準とした。[Effect of Turning Property by Containing Gerenite Powder and Anorthite Powder in Comparison with MnS Powder Containing Material] Iron powder-2% Cu-0.5% C (carbon) is used as a basic composition, and MnO and MnS are used. The amount of iron is almost equal, but iron powders having different Mn and S contents are used, and a mixed powder containing 0.1% of a grenite powder or anorthite powder having an average particle diameter of 15 μm is used. Forming density 6.90 g / cm 3
The powder compact of was produced. This molded body is 1130 ° C x 3
Sintering was carried out for 0 minutes, and a machinability test piece was prepared in the same manner as above for the obtained sintered body. Further, as a known MnS powder additive used for improving machinability, 0.5
% Iron powder (manufactured by Mitsui Kinzoku Co., Ltd.) containing MnS powder, was similarly compacted and sintered, and used as a standard for machinability evaluation.
【0047】被削性試験は、切削工具としてP種超硬チ
ップを使い、乾式、切り込みt=0.5mm、送りf=
0.1mm/rev、周速V=70〜200m/min
で旋削を行なった。結果を表6に示す。表中の工具寿命
比とは、同一旋削条件における0.5%MnS粉末添加
材を用いた焼結体の工具寿命時間(工具の摩耗量が所定
の値に達するまでの時間)を1とし、この値に対する相
対値として示した。In the machinability test, a P-type cemented carbide tip was used as a cutting tool, dry type, incision t = 0.5 mm, feed f =
0.1 mm / rev, peripheral speed V = 70 to 200 m / min
Turned in. The results are shown in Table 6. The tool life ratio in the table means that the tool life time (time until the wear amount of the tool reaches a predetermined value) of the sintered body using the 0.5% MnS powder additive under the same turning condition is 1, It is shown as a relative value to this value.
【0048】表6からも明らかである様に、ベースとな
る鉄粉中に含まれるMn量は、MnO,MnS以外の状
態で存在する場合、強度に影響を及ぼさない範囲で少な
い方が好ましいことが分かる。更に、ゲーレナイト粉末
およびアノールサイト粉末含有材を用いた焼結体では、
周速120m/min以上の高速旋削において、0.5
%MnS粉末添加材に比べて顕著な被削性改善効果が発
揮されることを確認できる。As is clear from Table 6, when the amount of Mn contained in the iron powder used as the base is in a state other than MnO and MnS, it is preferable that it is as small as possible within the range that does not affect the strength. I understand. Furthermore, in a sintered body using a material containing a grenite powder and anorthite powder,
0.5 in high-speed turning with a peripheral speed of 120 m / min or more
It can be confirmed that a remarkable machinability improvement effect is exhibited as compared with the% MnS powder additive.
【0049】[0049]
【表6】 [Table 6]
【0050】[ゲーレナイト+MnS粉末の複合添加効
果:粒径の影響]上記において、ゲーレナイト粉末およ
びアノールサイト粉末を含有させることにより、高速旋
削加工時の被削性が著しく改善されることを明らかにし
た。しかしながら、小径の焼結部品の内・外周加工ある
いは大型部品であっても内径加工では、加工機械の性能
上の制約から、周速(直径×π×回転数)を過度に高め
ることが難しいことも多く、その場合は低速条件下での
切削が必要となる。そこで本発明者らは、低速領域での
旋削加工性改善についても検討を行った。[Effect of Combined Addition of Gerenite + MnS Powder: Effect of Particle Size] In the above description, it has been clarified that the machinability during high-speed turning is remarkably improved by containing the grenite powder and the anolsite powder. . However, it is difficult to increase the peripheral speed (diameter x π x number of revolutions) excessively in the inner / outer periphery processing of a small-diameter sintered part, or in the case of a large-sized part, due to the performance restrictions of the processing machine in the inner diameter processing. In many cases, cutting under low speed conditions is required. Therefore, the present inventors also studied improvement of turning workability in a low speed region.
【0051】即ち、鉄粉−2%Cu−0.5%Cを基本
組成とし、ゲーレナイト粉末またはアノールサイト粉末
の含有率を0.1%に固定し、表7に示す如くMnS粉
末の粒径や添加量を種々変えた混合粉末について、前記
と同様にして圧粉形成および焼結(1130℃×30m
in)して得た供試材の被削性試験を行ない、前記と同
様に、0.5%MnS粉末添加材を用いた焼結体の工具
寿命時間を1としたときの工具寿命比を調べ、表7に示
す結果を得た。That is, iron powder-2% Cu-0.5% C was used as the basic composition, the content rate of the grenite powder or anorthite powder was fixed at 0.1%, and the particle size of the MnS powder was as shown in Table 7. For the mixed powder with various additions and addition amounts, powder compaction and sintering (1130 ° C. × 30 m
in), the machinability test of the test material obtained was performed, and the tool life ratio when the tool life time of the sintered body using the 0.5% MnS powder additive was set to 1 in the same manner as above. The results are shown in Table 7.
【0052】[0052]
【表7】 [Table 7]
【0053】表7からも明らかである様に、ゲーレナイ
ト粉末またはアノールサイト粉末と併用するMnS粉末
が粗粒である場合は、工具寿命の向上への寄与は小さい
が、その平均粒径が65μm程度未満の微細なものを使
用すると、少量でも0.5%MnS粉末添加材とほぼ近
い被削性を得ることができる。またMnS粉末の含有量
については、0.1%未満ではそれほどの寿命延長効果
は認められないが、0.1%以上のMnS粉末を併用す
ると、特に低速切削時における工具寿命の延長に有効に
作用することが伺われる。ただし、MnS含有量が多く
なり過ぎると、焼結体の機械的特性や疲労特性に悪影響
が現われてくるので、MnS粉末の含有量は0.7%以
下に抑えることが望ましい。As is clear from Table 7, when the MnS powder used in combination with the grenite powder or the anorthite powder is coarse, the contribution to the improvement of the tool life is small, but the average particle size is about 65 μm. If a fine powder of less than 0.5 is used, machinability close to that of the 0.5% MnS powder additive can be obtained even with a small amount. Regarding the content of MnS powder, when the content is less than 0.1%, the life extension effect is not so great, but when 0.1% or more of MnS powder is used together, it is particularly effective in extending the tool life during low speed cutting. It seems to work. However, if the MnS content becomes too large, the mechanical properties and fatigue properties of the sintered body will be adversely affected, so the MnS powder content is preferably controlled to 0.7% or less.
【0054】即ちゲーレナイト粉末またはアノールサイ
ト粉末とMnS粉末を併用する際には、平均粒径が65
μm以下であるMnS粉末を0.1〜0.7%程度併用
することによって、両者の併用効果を有効に活かすこと
が可能となる。特に、切削加工速度が遅くて工具の温度
が十分に上昇せず、ゲーレナイトまたはアノールサイト
の保護皮膜形成による被削性改善(工具保護)が満足に
期待できない様な低速旋削加工領域においては、MnS
粉末の有する旋削性改善効果を有効に発揮させることに
よって、低速切削から高速切削の全領域にわたって優れ
た被削性を確保することが可能となる。That is, when the grenenite powder or the anolsite powder and MnS powder are used in combination, the average particle size is 65.
By using 0.1 to 0.7% of MnS powder having a particle size of μm or less together, it is possible to effectively utilize the combined effect of both. Especially in the low-speed turning region where the cutting speed is slow and the temperature of the tool does not rise sufficiently and machinability improvement (tool protection) due to the formation of a protective film of gehlenite or anorthite cannot be expected satisfactorily.
By effectively exhibiting the turning property improving effect of the powder, it becomes possible to secure excellent machinability over the entire range from low speed cutting to high speed cutting.
【0055】なお、前記「精密工学会誌」に示唆されて
いるMnS粉末との併用による被削性改善効果の向上
は、100〜200m/minの高速旋削加工におい
て、MnS中に不純物として存在するMnOが、工具表
面へのゲーレナイトの付着を容易にするためとしている
が、本発明では上記の様に、切削加工速度が遅くて工具
の温度が十分に上昇せず、ゲーレナイトやアノールサイ
トの保護皮膜形成による被削性改善(工具保護)が不十
分となる低速旋削加工領域においても、満足のいく旋削
加工性を発揮させるため、その様な加工域での被削性を
MnS粉末によって補うものである。The improvement of the machinability improvement effect by the combined use with MnS powder suggested in the above-mentioned "Journal of Precision Engineering" is that MnO existing as an impurity in MnS in high-speed turning at 100 to 200 m / min. However, in order to facilitate the attachment of gehrenite to the tool surface, in the present invention, as described above, the cutting speed is slow and the temperature of the tool does not rise sufficiently, thus forming a protective film for gehrenite and anorthite. Even in the low-speed turning area where the machinability improvement (tool protection) due to is insufficient, the machinability in such a machining area is supplemented by MnS powder in order to exert satisfactory turning machinability. .
【0056】つまり本発明において、ゲーレナイトやア
ノールサイト粉末とMnS粉末を併用した焼結体では、
低速での被削性改善をMnS粉末によって確保し、高速
切削領域の被削性はゲーレナイト粉末および/またはア
ノールサイト粉末に由来する保護被膜によって受け持た
せ、いわば2段の被削性改善機能を持たせることによっ
て、高速切削はもとより低速切削領域においても、安定
して優れた被削性が確保できる様にしたところに大きな
特徴が存在する。That is, in the present invention, in the sintered body in which the MnS powder is used in combination with the grenite or anorthite powder,
The machinability improvement at low speed is secured by MnS powder, and the machinability in the high-speed cutting area is taken care of by the protective coating derived from the grenite powder and / or anorthite powder, so to speak, a two-step machinability improvement function. A major feature of this is that it is possible to stably ensure excellent machinability not only in high-speed cutting but also in a low-speed cutting region by providing it.
【0057】[Mn・Sプレアロイ型鉄粉+ゲーレナイ
ト粉末および/またはアノールサイト粉末の併用例]前
記において、ゲーレナイト粉末またはアノールサイト粉
末とMnS粉末を併用すると、焼結体の低速加工域から
高速加工域に渡る全加工領域での被削性が改善されるこ
とを示した。しかしながら、MnS粉末を含有させる方
法では、大気中で放置するとMnS粉末が変質して被
削性改善効果が低下するので、混合粉末の保管に特別の
措置を講じなければならない、鉄粉の酸化防止のため
H2 雰囲気で焼結を行なうと、H2 Sが発生して焼結炉
を痛めるばかりでなく作業環境を汚染する、MnS粉
末を含有させると焼結体が強度劣化を起こすので、Cや
Cu,Ni,Mo等の強化元素を余分に含有させなけれ
ばならない、MnS粉末を含有させると焼結時の寸法
変化率が変わってくるため、MnS粉末含有量に応じた
基礎データを作製すると共に専用の金型を準備しなけれ
ばならなくなる、といった、MnS粉末使用に伴う固有
の問題が生じてくる。[Example of combined use of Mn.S prealloy type iron powder + gerenite powder and / or anolsite powder] In the above, when the grenite powder or anorthite powder is used in combination with MnS powder, high speed machining from a low speed machining range of the sintered body is carried out. It was shown that the machinability in the entire machining area over the area was improved. However, in the method of containing MnS powder, if left in the air, the MnS powder deteriorates and the machinability improving effect decreases, so special measures must be taken to store the mixed powder. Therefore, when sintering is performed in an H 2 atmosphere, H 2 S is generated, which not only damages the sintering furnace but also contaminates the working environment. The inclusion of MnS powder causes the sintered body to deteriorate in strength. And strengthening elements such as Cu, Ni, Mo, etc. must be additionally contained. If MnS powder is contained, the dimensional change rate at the time of sintering will change. Therefore, basic data is prepared according to the MnS powder content. At the same time, a unique problem arises with the use of MnS powder, such as having to prepare a dedicated mold.
【0058】そこで、本発明者らはこうしたMnS粉末
使用に伴う固有の問題についても改善すべく、MnSを
粉末として含有させるのではなく、主成分である鉄粉中
に固溶状態で含有させることによって同様の被削性改善
効果を得ることはできないかと考え、こうした観点から
の研究も行なった。また本発明者らは他の実験におい
て、混合粉末中に配合される被削性改善成分の種類によ
っては、旋削加工とドリル穿孔加工に適用したときの被
削性にも違いがでてくることを知ったので、そうした観
点からの検討も行なった。Therefore, in order to improve the problems inherent to the use of MnS powder, the inventors of the present invention do not include MnS as a powder, but rather add it in a solid solution state in the iron powder as the main component. We also wondered if a similar machinability improvement effect could be obtained by this method, and conducted research from this perspective. Further, in other experiments, the inventors of the present invention showed that the machinability when applied to the turning process and the drilling process may differ depending on the type of the machinability improving component mixed in the mixed powder. Since I knew that, I also examined from that perspective.
【0059】まず図9に、Fe−2%Cu−0.5%C
を基本組成とする混合粉末(神戸製鋼所製、商品名「ア
トメル300M」)を用いた焼結材の乾式ドリル穿孔試
験結果(V−L線図)を示す。この図からも明らかであ
る様に、0.1%ゲーレナイト粉末含有材は、ハイスド
リルの穿孔において無添加材よりも工具寿命が短くな
る。これは、旋削加工とドリル穿孔では切削のメカニズ
ムが異なること、穿孔では工具の周速を高めにいくこ
と、ハイス工具にはゲーレナイトの保護皮膜(ベラー
ク)が付着しにくいこと、さらにゲーレナイトが介在物
的な作用をすることなどが考えられる。一方、0.5%
MnS粉末添加材では、ハイスドリル穿孔でも著しい改
善効果を示すが、前記〜で示した様な難点が生じて
くる。First, in FIG. 9, Fe-2% Cu-0.5% C
The dry drilling test result (VL diagram) of a sintered material using a mixed powder having a basic composition of (Kobe Steel Co., Ltd., trade name "Atmel 300M") is shown. As is clear from this figure, the material containing 0.1% gerenic powder has a shorter tool life in drilling a high-speed drill than the additive-free material. This is because the cutting mechanism is different between turning and drilling, increasing the peripheral speed of the tool in drilling, making it difficult for the protective film (bererk) of Gerenite to adhere to the HSS tool, and the inclusion of Gerenite as an inclusion. It can be considered that it has a positive effect. On the other hand, 0.5%
The MnS powder added material shows a remarkable improvement effect even with high-speed drilling, but the above-mentioned problems occur.
【0060】また図10は、MnとSを固溶状態で含有
する鉄粉(Mn・Sプレアロイ型鉄粉:組成は表8に示
す)を使用し、これに0.1重量%のゲーレナイトを含
有させた混合粉末を原料として用いた焼結体のドリル穿
孔試験の結果を示したものであり、Mn・Sプレアロイ
型鉄粉をベース鉄粉として用いることにより、0.5%
MnS粉末を含有させた混合粉末を用いた焼結体とほぼ
同等のドリル穿孔性を確保できることが分かる。そして
この方法であれば、MnS粉末を使用することにより生
じてくる前述の様な問題点を全く生じることなく、Mn
S粉末を含有させたのに比べても遜色のない被削性改善
効果を得ることが可能となる。In FIG. 10, iron powder containing Mn and S in a solid solution state (Mn.S prealloy type iron powder: composition is shown in Table 8) was used, and 0.1% by weight of gerenicite was added thereto. The results of a drilling test of a sintered body using the mixed powder contained as a raw material are shown. By using Mn.S prealloy type iron powder as a base iron powder, 0.5% is obtained.
It can be seen that it is possible to secure substantially the same drill piercing property as the sintered body using the mixed powder containing the MnS powder. With this method, MnS powder can be used without causing the above-mentioned problems caused by using MnS powder.
It becomes possible to obtain a machinability improving effect comparable to that containing S powder.
【0061】[0061]
【表8】 [Table 8]
【0062】この場合、鉄粉中に含まれるS含有量につ
いては、0.15重量%未満では被削性改善効果が乏し
く、0.5重量%を超えると圧縮性を著しく低下させる
ので、鉄粉中のS含有量は0.15〜0.5重量%の範
囲にすべきである。一方、鉄粉中のMnは、それ自身で
被削性向上に寄与するのではなく、鉄粉中に含まれるS
を固定して焼結時の脱硫を防止し、Sの被削性改善効果
を有効に発揮させる元素である。従ってその含有率は、
S含有量との関係或は焼結時に起こる脱硫の程度によっ
ても変わってくる。In this case, regarding the S content contained in the iron powder, if the S content is less than 0.15% by weight, the machinability improving effect is poor, and if it exceeds 0.5% by weight, the compressibility is remarkably reduced. The S content in the powder should be in the range of 0.15-0.5% by weight. On the other hand, Mn in the iron powder does not contribute to the improvement of the machinability by itself, but is contained in the iron powder.
Is an element that fixes desaturation to prevent desulfurization during sintering and effectively exerts the machinability improving effect of S. Therefore, its content rate is
It also depends on the relationship with the S content or the degree of desulfurization that occurs during sintering.
【0063】即ち、焼結をAXガス(アンモニア分解ガ
ス:H2 =75%、N2 =25%)やブタン変性ガス等
の水素含有雰囲気ガス中で行なうと、焼結工程で脱硫反
応(H2 +S→H2 S)が進行するので、SをMnSと
して固定する為のMnが必要となり、その固定効果はS
量に対して化学当量以上のMnを含有させることによっ
て有効に発揮される。但し、化学当量を超えてMn含有
量が過度に多くなると、鉄粉の製造工程でMnOが生成
して圧縮性に悪影響を及ぼす様になる。こうした障害を
回避するには、Mn含有量をS量に対する化学当量+
0.3重量%以下に抑えるべきである。That is, when the sintering is performed in a hydrogen-containing atmosphere gas such as AX gas (ammonia decomposition gas: H 2 = 75%, N 2 = 25%) or butane modification gas, the desulfurization reaction (H 2 + S → H 2 S) progresses, Mn is required to fix S as MnS, and the fixing effect is S
It is effectively exhibited by containing Mn in a chemical equivalent amount or more with respect to the amount. However, if the Mn content exceeds the chemical equivalent and the Mn content becomes excessively high, MnO is produced in the iron powder manufacturing process, which adversely affects the compressibility. In order to avoid such obstacles, the Mn content should be the chemical equivalent to the S content +
It should be kept below 0.3% by weight.
【0064】但し、最近では寸法精度向上などを目的と
して、焼結をN2 雰囲気で行なう例も増大してきてお
り、この様な場合は焼結時の脱硫は問題とはならず、S
固定のためのMnの含有は必要でなく、この場合はMn
を添加しなくとも差し支えない。However, recently, for the purpose of improving dimensional accuracy and the like, the number of cases where sintering is performed in an N 2 atmosphere is increasing, and in such a case, desulfurization at the time of sintering is not a problem, and S
It is not necessary to include Mn for fixing, in this case Mn
It does not matter even if you do not add.
【0065】ちなみに下記表9は、鉄粉−2%Cu−
0.5%Cを基本組成とする市販のアトマイズ鉄粉(神
戸製鋼所製、商品名「アトメル300M」)に0.3%
のMn粉末(平均粒径45μm)と0.1%のゲーレナ
イト粉末(粒径15μm)を複合添加した材料と、S含
有量を種々変更した鉄粉と0.1%のゲーレナイト粉末
(粒径15μm)を複合添加した材料について、成形密
度6.9g/cm3 の圧粉成形体を作製し、1130℃
×30minで焼結して得た供試材について、被削性試
験と焼結体の脱硫実験を行なった結果を示したものであ
る。By the way, Table 9 below shows iron powder-2% Cu-
0.3% in commercially available atomized iron powder with 0.5% C as basic composition (Kobe Steel, trade name "Atmel 300M")
Of Mn powder (average particle size: 45 μm) and 0.1% of grenenite powder (particle size: 15 μm) were added in combination, iron powder with various S content changes, and 0.1% of grenite powder (particle size: 15 μm) ), A powder compact having a compacting density of 6.9 g / cm 3 was produced,
The results of a machinability test and a desulfurization experiment of a sintered body are shown for a test material obtained by sintering at × 30 min.
【0066】なお被削性試験は、乾式の外周旋削で切削
速度V=70および200m/min、切り込みt=
0.5mm、送り速度f=0.1mm/revとし、工
具の逃げ面摩耗VB=0.3mmを寿命とした。また、
水素ガスを含む焼結雰囲気では前述の如く脱硫反応が進
行し易いので、焼結品の表面を化学分析し、添加したS
(計算値を含む)からの減少率が4%以上になったもの
を脱硫有りと判定した。表中のAXとは、焼結雰囲気ガ
スとして用いたアンモニア分解ガス(H2 =75%、N
2 =25%)を表わしている。The machinability test was carried out by dry type outer peripheral turning with a cutting speed V = 70 and 200 m / min and a cut t =
The life was set to 0.5 mm, the feed rate f = 0.1 mm / rev, and the flank wear of the tool VB = 0.3 mm. Also,
Since the desulfurization reaction easily proceeds in the sintering atmosphere containing hydrogen gas as described above, the surface of the sintered product was chemically analyzed and S added.
When the reduction rate from (including the calculated value) was 4% or more, it was determined that there was desulfurization. AX in the table means the ammonia decomposition gas used as the sintering atmosphere gas (H 2 = 75%, N 2
2 = 25%).
【0067】[0067]
【表9】 [Table 9]
【0068】表9において、参考例21と22を除き、
MnS粉末添加材とS含有鉄粉使用材は水素含有雰囲気
中での焼結で脱硫を起こしているが、N2 雰囲気では脱
硫が認められない。このことから、N2 雰囲気中で焼結
を行なう場合は、MnによるSの固定が必要でないこと
が分かる。また0.3%のMnS粉末を添加している参
考例20と同等以上の工具寿命を低速(70m/mi
n)旋削で確保するには、鉄粉中に固溶しているS量を
0.15%以上とすべきであり、S量が増大するにつれ
て、特に低速切削加工時の工具寿命比は著しく改善され
ることを確認できる。尚参考例24の工具寿命比は良好
であるが、粉末の圧縮性に悪影響が現れてくるので、S
含有量はこうした欠点を生じない0.5%以下に抑える
のが良い。In Table 9, except for Reference Examples 21 and 22,
The MnS powder additive material and the S-containing iron powder material are desulfurized by sintering in a hydrogen-containing atmosphere, but no desulfurization is observed in an N 2 atmosphere. From this, it is understood that it is not necessary to fix S by Mn when sintering is performed in an N 2 atmosphere. In addition, the tool life equivalent to or higher than that of Reference Example 20 in which 0.3% MnS powder was added was set to low speed (70 m / mi).
n) In order to secure by turning, the amount of S dissolved in iron powder should be 0.15% or more. As the amount of S increases, the tool life ratio during low-speed cutting is particularly remarkable. You can confirm that it will be improved. The tool life ratio of Reference Example 24 is good, but the compressibility of the powder is adversely affected.
The content is preferably 0.5% or less, which does not cause such defects.
【0069】次に表10は、前記表9と同じ試験法で、
アノールサイトを用いて水素含有雰囲気中での焼結時の
脱硫について検討した結果を示している。表中Mn/S
とは、鉄粉中のMn量がS量の何倍に相当するかを表わ
しており、鉄粉中の全てのSがMnSとして固定される
ためのMn/Sは1.71となるので、その基準でMn
量の過不足分を(%)で表わしている。Next, Table 10 shows the same test method as in Table 9 above.
The results of studying desulfurization during sintering in an atmosphere containing hydrogen using anolsite are shown. Mn / S in the table
Means how many times the amount of Mn in the iron powder corresponds to the amount of S, and Mn / S for fixing all S in the iron powder as MnS is 1.71, so Mn on that basis
The excess or deficiency of the amount is represented by (%).
【0070】[0070]
【表10】 [Table 10]
【0071】表10からも明らかである様に、Mn/S
が1.71を下回るものでは焼結時に脱硫が起こってい
る。一方、過剰量のMnは、鉄粉の製造工程でその多く
がMnOとなり、特に高速旋削加工における工具寿命比
を高める傾向を伺うことができるが、Mn過剰量が0.
3%を超えると鉄粉の圧縮性が悪くなるので、過剰に加
えるにしてもその量は(1.71×S量+0.3%)以
下に抑えるべきである。As is clear from Table 10, Mn / S
Of less than 1.71 causes desulfurization during sintering. On the other hand, an excessive amount of Mn is mostly MnO in the iron powder manufacturing process, and it can be seen that there is a tendency to increase the tool life ratio particularly in high-speed turning.
If it exceeds 3%, the compressibility of the iron powder will deteriorate, so even if it is added excessively, its amount should be suppressed to (1.71 × S amount + 0.3%) or less.
【0072】[0072]
【発明の効果】本発明は以上の様に構成されており、平
均粒径が50μm以下、より好ましくは10μm以下の
アノールサイト粉末および/またはゲーレナイト粉末を
被削性改善成分として使用することによって、焼結体の
強度を損なうことなく、焼結時における寸法変化率の調
整が容易であり、しかも旋削はもとよりドリル穿孔に対
しても優れた被削性を有する焼結体を与える粉末冶金用
鉄系混合粉末を提供し得ることになった。The present invention is constituted as described above, and by using an anolsite powder and / or a grenite powder having an average particle size of 50 μm or less, more preferably 10 μm or less as a machinability improving component, Iron for powder metallurgy that can easily adjust the dimensional change rate during sintering without deteriorating the strength of the sintered body and has excellent machinability not only for turning but also for drilling. It has been possible to provide a system mixed powder.
【0073】また、アノールサイト粉末および/または
ゲーレナイト粉末と共に、平均粒子径の特定されたMn
S粉末を併用すれば、高速切削はもとより低速切削にお
いても非常に優れた被削性を有する焼結体を得ることが
でき、更にはMnS粉末を併用する代わりに、ベース鉄
粉として所定量のMnとSを固溶状態で含有する鉄粉を
使用すれば、MnS粉末を使用することによって生じる
問題も回避することが可能となる。また本発明において
は、通常の粉末冶金用鉄系粉末に好ましく配合されるグ
ラファイト粉末および/または物性改善用金属粉末、あ
るいは潤滑剤や偏析防止剤を配合することによってそれ
らの特徴を有効に活かすことも可能である。In addition to the anolsite powder and / or the grenenite powder, the Mn having the specified average particle size is specified.
When S powder is used together, a sintered body having excellent machinability not only in high speed cutting but also in low speed cutting can be obtained. Furthermore, instead of using MnS powder together, a predetermined amount of base iron powder is used. If the iron powder containing Mn and S in a solid solution state is used, it is possible to avoid the problem caused by using the MnS powder. Further, in the present invention, graphite powder and / or metal powder for improving physical properties, which are preferably blended with an iron-based powder for ordinary powder metallurgy, or a lubricant or an anti-segregation agent is blended to effectively utilize those characteristics. Is also possible.
【0074】そしてこれらの混合粉末を圧粉成形した後
の焼結温度を650〜1500℃の範囲に設定すること
によって、上記粉末冶金用鉄系混合粉末の特徴を最大限
有効に生かして、安定した寸法精度のもとで強度および
被削性に非常に優れた焼結製品を効率よく得ることが可
能となる。By setting the sintering temperature after compaction molding of these mixed powders in the range of 650 to 1500 ° C., the characteristics of the iron-based mixed powder for powder metallurgy described above are effectively utilized to the maximum and stable. With the above dimensional accuracy, it becomes possible to efficiently obtain a sintered product having excellent strength and machinability.
【図1】混合粉末中のゲーレナイト粉末含有量を変えた
ときの、成形体密度と焼結時(1120℃)の外径変化
率の関係を調べた結果を示すグラフである。FIG. 1 is a graph showing the results of investigating the relationship between the density of compacts and the rate of change in outer diameter during sintering (1120 ° C.) when the content of the grenenite powder in the mixed powder was changed.
【図2】混合粉末中のゲーレナイト粉末含有量を変えた
ときの、成形体密度と焼結時(1250℃)の外径変化
率の関係を調べた結果を示すグラフである。FIG. 2 is a graph showing the results of examining the relationship between the density of a compact and the rate of change in outer diameter at the time of sintering (1250 ° C.) when the content of the grenenite powder in the mixed powder was changed.
【図3】混合粉末中のアノールサイト粉末含有量を変え
たときの、成形体密度と焼結時(1120℃)の外径変
化率の関係を調べた結果を示すグラフである。FIG. 3 is a graph showing the results of examining the relationship between the compact density and the outer diameter change rate during sintering (1120 ° C.) when the content of the anolsite powder in the mixed powder was changed.
【図4】混合粉末中のアノールサイト粉末含有量を変え
たときの、成形体密度と焼結時(1250℃)の外径変
化率の関係を調べた結果を示すグラフである。FIG. 4 is a graph showing the results of examining the relationship between the compact density and the outer diameter change rate during sintering (1250 ° C.) when the content of the anolsite powder in the mixed powder was changed.
【図5】ゲーレナイト粉末無添加材と0.3%添加材の
焼結温度と焼結時の外径寸法変化率を示すグラフであ
る。FIG. 5 is a graph showing a sintering temperature and an outside diameter dimensional change rate during sintering of a material without addition of a gehlenite powder and a material with addition of 0.3%.
【図6】ゲーレナイト粉末含有率を変えた混合粉末の、
焼結及び冷却時の寸法変化の挙動を示すグラフである。FIG. 6 is a graph showing mixed powders having different contents of gehlenite powder.
It is a graph which shows the behavior of dimensional change at the time of sintering and cooling.
【図7】アノールサイト粉末含有率を変えた混合粉末
の、焼結及び冷却時の寸法変化の挙動を示すグラフであ
る。FIG. 7 is a graph showing the behavior of dimensional changes during sintering and cooling of mixed powders having different contents of anolyte powder.
【図8】CaO−Al2 O3 −SiO2 系状態図であ
る。FIG. 8 is a CaO—Al 2 O 3 —SiO 2 system phase diagram.
【図9】ゲーレナイト粉末添加材、MnS粉末添加材お
よび無添加材の切削速度と工具寿命の関係を示すグラフ
である。FIG. 9 is a graph showing the relationship between the cutting speed and the tool life of the material added with a grenite powder, the material added with a MnS powder, and the material without an additive.
【図10】鉄粉としてMn・Sプレアロイ鉄粉を使用
し、ゲーレナイト粉末を含有させた場合の切削速度と工
具寿命の関係を示すグラフである。FIG. 10 is a graph showing the relationship between cutting speed and tool life when Mn.S prealloyed iron powder is used as the iron powder and a grenite powder is contained.
フロントページの続き (58)調査した分野(Int.Cl.7,DB名) B22F 1/00 Continuation of front page (58) Fields surveyed (Int.Cl. 7 , DB name) B22F 1/00
Claims (7)
を主体とし、アノールサイト相および/またはゲーレナ
イト相を有する平均粒径50μm以下のCaO−Al2
O3 −SiO2 系複合酸化物の粉末を0.02〜0.3
重量%含有することを特徴とする粉末冶金用鉄系混合粉
末。1. An iron-based mixed powder for powder metallurgy, which comprises mainly iron powder and has an anorthite phase and / or a grenenite phase and an average particle size of 50 μm or less CaO—Al 2
Add powder of O 3 —SiO 2 composite oxide to 0.02 to 0.3
An iron-based mixed powder for powder metallurgy, characterized in that the iron-based mixed powder is contained in a weight percentage.
である請求項1に記載の粉末冶金用鉄系混合粉末。2. The iron-based mixed powder for powder metallurgy according to claim 1, wherein the composite oxide has an average particle diameter of 12 μm or less.
量%、Mn含有量が、該S量に対し化学当量のMn量+
0.3重量%以下である請求項1または2に記載の粉末
冶金用鉄系混合粉末。3. The iron powder has an S content of 0.15 to 0.5% by weight, and an Mn content of the iron powder is a chemical equivalent of the Mn amount +
The iron-based mixed powder for powder metallurgy according to claim 1 or 2, which is 0.3% by weight or less.
下のMnS粉末を0.1〜0.7重量%含むものである
請求項1または2に記載の粉末冶金用鉄系混合粉末。4. The iron-based mixed powder for powder metallurgy according to claim 1, which contains 0.1 to 0.7% by weight of MnS powder having an average particle diameter of 65 μm or less as another component.
および/または物性改善用金属粉末が含まれている請求
項1〜4のいずれかに記載の粉末冶金用鉄系混合粉末。5. The iron-based mixed powder for powder metallurgy according to claim 1, further comprising graphite powder and / or metal powder for improving physical properties as other components.
止剤が添加されたものである請求項1〜5のいずれかに
記載の粉末冶金用鉄系混合粉末。6. The iron-based mixed powder for powder metallurgy according to claim 1, wherein a lubricant or an anti-segregation agent is added as another component.
末冶金用鉄系混合粉末を圧粉成形し、650〜1500
℃で焼結することを特徴とする焼結体の製法。7. A compacting the powder metallurgical iron-based mixed powder according to any of claims 1 to 6, 650-1500
A method for producing a sintered body, which comprises sintering at ℃.
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Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
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US20180126454A1 (en) * | 2015-05-27 | 2018-05-10 | Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.) | Mixed powder for iron-based powder metallurgy and sintered body produced using same |
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