JP2003096533A - Iron-base powder mixture for warm compaction, iron-base powder mixture for warm die lubrication compaction, and method for manufacturing iron-base sintered compact using them - Google Patents
Iron-base powder mixture for warm compaction, iron-base powder mixture for warm die lubrication compaction, and method for manufacturing iron-base sintered compact using themInfo
- Publication number
- JP2003096533A JP2003096533A JP2002209042A JP2002209042A JP2003096533A JP 2003096533 A JP2003096533 A JP 2003096533A JP 2002209042 A JP2002209042 A JP 2002209042A JP 2002209042 A JP2002209042 A JP 2002209042A JP 2003096533 A JP2003096533 A JP 2003096533A
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- Japan
- Prior art keywords
- iron
- powder
- based powder
- powder mixture
- warm
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- 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.)
- Pending
Links
- 239000000843 powder Substances 0.000 title claims abstract description 199
- 239000000203 mixture Substances 0.000 title claims abstract description 82
- 238000000034 method Methods 0.000 title claims abstract description 34
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 21
- 238000005461 lubrication Methods 0.000 title claims description 34
- 238000005056 compaction Methods 0.000 title abstract description 6
- 239000000314 lubricant Substances 0.000 claims abstract description 59
- 239000002245 particle Substances 0.000 claims abstract description 48
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 28
- 239000011164 primary particle Substances 0.000 claims abstract description 28
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 347
- 229910052742 iron Inorganic materials 0.000 claims description 171
- 238000000465 moulding Methods 0.000 claims description 72
- 239000011163 secondary particle Substances 0.000 claims description 18
- 239000003795 chemical substances by application Substances 0.000 claims 1
- 238000005245 sintering Methods 0.000 abstract description 26
- 238000010438 heat treatment Methods 0.000 description 19
- 229910002804 graphite Inorganic materials 0.000 description 12
- 239000010439 graphite Substances 0.000 description 12
- 230000000052 comparative effect Effects 0.000 description 11
- 229910000831 Steel Inorganic materials 0.000 description 9
- 239000010959 steel Substances 0.000 description 9
- 238000011282 treatment Methods 0.000 description 9
- 238000005452 bending Methods 0.000 description 8
- 238000011049 filling Methods 0.000 description 7
- 230000007423 decrease Effects 0.000 description 6
- 238000002156 mixing Methods 0.000 description 6
- 238000004663 powder metallurgy Methods 0.000 description 6
- 229910045601 alloy Inorganic materials 0.000 description 5
- 239000000956 alloy Substances 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 239000007789 gas Substances 0.000 description 5
- 238000010791 quenching Methods 0.000 description 5
- 230000000171 quenching effect Effects 0.000 description 5
- XOOUIPVCVHRTMJ-UHFFFAOYSA-L zinc stearate Chemical compound [Zn+2].CCCCCCCCCCCCCCCCCC([O-])=O.CCCCCCCCCCCCCCCCCC([O-])=O XOOUIPVCVHRTMJ-UHFFFAOYSA-L 0.000 description 5
- 239000002184 metal Substances 0.000 description 4
- 229910052751 metal Inorganic materials 0.000 description 4
- RKISUIUJZGSLEV-UHFFFAOYSA-N n-[2-(octadecanoylamino)ethyl]octadecanamide Chemical compound CCCCCCCCCCCCCCCCCC(=O)NCCNC(=O)CCCCCCCCCCCCCCCCC RKISUIUJZGSLEV-UHFFFAOYSA-N 0.000 description 4
- 238000005728 strengthening Methods 0.000 description 4
- 238000007088 Archimedes method Methods 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 3
- 238000005255 carburizing Methods 0.000 description 3
- 229910052802 copper Inorganic materials 0.000 description 3
- 239000010949 copper Substances 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 238000005242 forging Methods 0.000 description 3
- 229910052739 hydrogen Inorganic materials 0.000 description 3
- HGPXWXLYXNVULB-UHFFFAOYSA-M lithium stearate Chemical compound [Li+].CCCCCCCCCCCCCCCCCC([O-])=O HGPXWXLYXNVULB-UHFFFAOYSA-M 0.000 description 3
- 230000001050 lubricating effect Effects 0.000 description 3
- 229910052750 molybdenum Inorganic materials 0.000 description 3
- 229910052759 nickel Inorganic materials 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- 238000005275 alloying Methods 0.000 description 2
- CJZGTCYPCWQAJB-UHFFFAOYSA-L calcium stearate Chemical compound [Ca+2].CCCCCCCCCCCCCCCCCC([O-])=O.CCCCCCCCCCCCCCCCCC([O-])=O CJZGTCYPCWQAJB-UHFFFAOYSA-L 0.000 description 2
- 239000008116 calcium stearate Substances 0.000 description 2
- 235000013539 calcium stearate Nutrition 0.000 description 2
- 238000005520 cutting process Methods 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 238000000605 extraction Methods 0.000 description 2
- 238000009661 fatigue test Methods 0.000 description 2
- 230000006698 induction Effects 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 239000011148 porous material Substances 0.000 description 2
- 239000000344 soap Substances 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 1
- 102100033029 Carbonic anhydrase-related protein 11 Human genes 0.000 description 1
- 229910001018 Cast iron Inorganic materials 0.000 description 1
- 101000867841 Homo sapiens Carbonic anhydrase-related protein 11 Proteins 0.000 description 1
- 101001075218 Homo sapiens Gastrokine-1 Proteins 0.000 description 1
- 101100219325 Phaseolus vulgaris BA13 gene Proteins 0.000 description 1
- 229910001035 Soft ferrite Inorganic materials 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 229910001873 dinitrogen Inorganic materials 0.000 description 1
- 238000005469 granulation Methods 0.000 description 1
- 230000003179 granulation Effects 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 125000004435 hydrogen atom Chemical class [H]* 0.000 description 1
- 150000002505 iron Chemical class 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 239000011812 mixed powder Substances 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 229910001562 pearlite Inorganic materials 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 238000007873 sieving Methods 0.000 description 1
- 238000004513 sizing Methods 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
Landscapes
- Powder Metallurgy (AREA)
Abstract
Description
【発明の詳細な説明】Detailed Description of the Invention
【0001】[0001]
【発明の属する技術分野】本発明は、温間成形用鉄基粉
末混合物および温間金型潤滑成形用鉄基粉末混合物なら
びにこれらを用いた鉄基焼結体の製造方法に係り、とく
に、高疲労強度を有する鉄基粉末焼結体の製造方法に関
する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an iron-based powder mixture for warm forming, an iron-based powder mixture for warm die lubrication forming, and a method for producing an iron-based sintered body using the same. The present invention relates to a method for manufacturing an iron-based powder sintered body having fatigue strength.
【0002】[0002]
【従来の技術】粉末冶金用鉄基粉末成形体は、鉄基粉末
に、銅粉、黒鉛粉などの合金粉末と、さらにステアリン
酸亜鉛、ステアリン酸リチウム等の潤滑剤を混合した鉄
基粉末混合物を金型に充填した後、加圧成形して製造さ
れるのが一般的であり、得られる鉄基粉末成形体の密度
としては、6.6 〜7.1 Mg/m3 が普通の値である。2. Description of the Related Art An iron-based powder compact for powder metallurgy is an iron-based powder mixture obtained by mixing iron-based powder with an alloy powder such as copper powder or graphite powder and a lubricant such as zinc stearate or lithium stearate. Is generally manufactured by pressure molding after filling in a metal mold, and the density of the obtained iron-based powder compact is generally 6.6 to 7.1 Mg / m 3 .
【0003】これらの鉄基粉末成形体は、焼結処理を施
して焼結体とされ、必要に応じてサイジングや切削加工
を施して粉末冶金製品とされる。また強度増加が必要な
粉末冶金製品の場合には焼結処理後に熱処理を施すこと
もある。このようにして製品形状に近い粉末冶金製品を
製造する粉末冶金技術により、高寸法精度で複雑な形状
の部品をニアネット形状に生産することが可能となり、
従来の溶製材料を用いる製造方法に比べて大幅に切削コ
ストの低減が可能となった。[0003] These iron-based powder compacts are subjected to a sintering treatment to obtain a sintered compact, and if necessary, subjected to sizing and cutting to obtain a powder metallurgy product. Further, in the case of powder metallurgy products that require increased strength, heat treatment may be performed after the sintering treatment. In this way, powder metallurgical technology for manufacturing powder metallurgical products close to the product shape makes it possible to produce parts with high dimensional accuracy and complex shapes in the near net shape,
The cutting cost can be significantly reduced compared to the conventional manufacturing method using ingot material.
【0004】さらに、最近では、自動車用機械部品など
に用いられる部品の小型軽量化のための高強度化が鉄系
の粉末冶金製品へ強く要求されている。粉末冶金製品
(焼結部品)の高強度化に対しては、成形体を高密度化
することにより、焼結部品を高密度化することが一般的
に有効であり、焼結部品の密度が高いほど、焼結部品中
の空孔が減少し、引張り強さや衝撃値をはじめ、疲労強
度などの機械的特性が向上する。Further, in recent years, there has been a strong demand for iron-based powder metallurgy products to have high strength in order to reduce the size and weight of parts used for automobile mechanical parts and the like. In order to increase the strength of powder metallurgy products (sintered parts), it is generally effective to densify the compact by densifying the compact, and The higher the value, the less the voids in the sintered part, and the better the mechanical properties such as tensile strength and impact value as well as fatigue strength.
【0005】鉄基粉末成形体の高密度化を可能とする成
形方法として、鉄基粉末混合物に通常の加圧成形と焼結
処理を施したのち、さらに加圧成形と焼結処理を繰り返
して行う2回成形2回焼結法や(例えば特開平10−3170
90号公報)、1回成形1回焼結後に熱間で鍛造する焼結
鍛造法などが提案されている。また、例えば、特開平2-
156002号公報、特公平7-103404号公報、USP 第5,256,18
5 号公報、USP 第5,368,630 号公報には、金属粉末を加
熱しつつ加圧成形する温間成形技術が開示されている。
この温間成形技術は、温間成形時に潤滑剤の一部または
全部を溶融させて粉末粒子間に潤滑剤を均一に分散さ
せ、粒子間および成形体と金型の間の摩擦抵抗を下げ成
形性を向上させようとするものであり、上記した高密度
成形体の製造方法のなかではコスト的には最も有利であ
ると考えられている。As a molding method capable of increasing the density of an iron-based powder compact, an iron-based powder mixture is subjected to usual pressure molding and sintering treatment, and then pressure molding and sintering treatment are repeated. Two-time molding, two-time sintering method or the like (for example, JP-A-10-3170).
No. 90), a sintering forging method is proposed in which forging is performed once and then hot forging is performed. In addition, for example, Japanese Patent Laid-Open No. 2-
No. 156002, Japanese Patent Publication No. 7-103404, USP No. 5,256,18
Japanese Patent No. 5 and USP No. 5,368,630 disclose a warm molding technique in which a metal powder is pressed while being heated.
This warm molding technology melts part or all of the lubricant during warm molding to evenly disperse the lubricant between powder particles, reducing friction resistance between particles and between the molded body and the mold. In order to improve the property, it is considered to be most advantageous in terms of cost among the above-mentioned methods for producing a high-density molded body.
【0006】[0006]
【発明が解決しようとする課題】しかしながら、特開平
2-156002号公報、特公平7-103404号公報、USP 第5,256,
185 号公報、USP 第5,368,630 号公報、特開2000−2907
03号公報に記載の温間成形技術で得た成形体を焼結処理
した鉄基焼結体では、鉄基焼結体を用いる部品によって
は、機械的特性が不十分であるという問題があった。SUMMARY OF THE INVENTION
2-156002, Japanese Patent Publication No. 7-103404, USP No. 5,256,
No. 185, USP No. 5,368,630, JP 2000-2907
In the iron-based sintered body obtained by sintering the molded body obtained by the warm forming technique described in JP-A No. 03-2003, there is a problem that mechanical properties are insufficient depending on the parts using the iron-based sintered body. It was
【0007】また、自動車用機械部品などに用いられる
焼結体として、高疲労強度化という観点と、コストの低
減という観点から、高疲労強度の鉄基焼結体を、しかも
1回の加圧成形で得ることのできる鉄基焼結体の製造方
法の開発が望まれていた。本発明は、上記した従来技術
の問題を有利に解決し、高密度成形体を焼結処理して、
高密度・高疲労強度の鉄基焼結体とすることができる温
間成形用鉄基粉末混合物および温間金型潤滑成形用鉄基
粉末混合物ならびにこれらを用いた鉄基焼結体の製造方
法を提案することを目的とする。Further, as a sintered body used for automobile machine parts and the like, an iron-based sintered body having a high fatigue strength is used from the viewpoints of high fatigue strength and cost reduction, and the pressure is applied once. It has been desired to develop a method for producing an iron-based sintered body that can be obtained by molding. The present invention advantageously solves the above-mentioned problems of the prior art, sintering the high-density molded body,
Iron-based powder mixture for warm forming, iron-based powder mixture for warm die lubrication forming, and iron-based sintered body manufacturing method using the same, which can be an iron-based sintered body with high density and high fatigue strength The purpose is to propose.
【0008】[0008]
【課題を解決するための手段】そこで本発明者らは、鉄
基粉末の最大粒径に着目した。従来粉末冶金用鉄基粉末
の1次粒子の最大粒径は150 〜180 μmであり、1次粒
子の最大粒径を小さくすることで上記問題点を解決でき
たのである。本発明者らは、鉄基粉末の1次粒子の最大
粒径を限定するとともに、黒鉛粉末および粉末成形用潤
滑剤の量を特定した鉄基粉末混合物を用いる温間成形技
術および、上記したような鉄基粉末混合物を加圧成形す
る金型を予め予熱し、予熱された金型の表面に帯電した
潤滑剤を塗布する温間金型潤滑技術を適用することによ
り、高密度成形体を得、これを焼結処理することで高密
度・高疲労強度の鉄基焼結体を製造できることを知見
し、本発明を完成させた。Therefore, the present inventors have focused on the maximum particle size of iron-based powder. Conventional iron-based powders for powder metallurgy have a maximum particle size of primary particles of 150 to 180 μm, and the problem can be solved by reducing the maximum particle size of the primary particles. The present inventors have limited the maximum particle size of the primary particles of the iron-based powder, and used the warm-forming technology using the iron-based powder mixture in which the amounts of the graphite powder and the lubricant for powder molding are specified, and as described above. A high-density molded product is obtained by applying a warm mold lubrication technique of preheating a mold for press molding a complex iron-based powder mixture and applying a charged lubricant to the surface of the preheated mold. The inventors have completed the present invention by finding that an iron-based sintered body with high density and high fatigue strength can be manufactured by sintering this.
【0009】すなわち、本発明は、鉄基粉末、黒鉛粉末
および粉末成形用潤滑剤とを含有する温間成形用鉄基粉
末混合物において、前記鉄基粉末の1次粒子の最大粒径
が75μm以下であり、前記温間成形用鉄基粉末混合物の
全量に対して、前記黒鉛粉末が0.1 〜1.0 質量%であ
り、前記粉末成形用潤滑剤が0.05〜0.80質量%であるこ
とを特徴とする温間成形用鉄基粉末混合物である。前記
鉄基粉末を、最大粒径が75μm以下の1次粒子を造粒し
た2次粒子とし、該2次粒子の最大粒径を180 μm 以下
としてなることが好ましい。That is, according to the present invention, in a warm-forming iron-based powder mixture containing iron-based powder, graphite powder and a powder-forming lubricant, the maximum particle size of primary particles of the iron-based powder is 75 μm or less. The graphite powder is 0.1 to 1.0% by mass, and the powder molding lubricant is 0.05 to 0.80% by mass with respect to the total amount of the warm-forming iron-based powder mixture. It is an iron-based powder mixture for hot compacting. It is preferable that the iron-based powder is a secondary particle obtained by granulating primary particles having a maximum particle size of 75 μm or less, and the maximum particle size of the secondary particle is 180 μm or less.
【0010】また、本発明は、鉄基粉末、黒鉛粉末およ
び粉末成形用潤滑剤とを含有する温間金型潤滑成形用鉄
基粉末混合物において、前記鉄基粉末の1次粒子の最大
粒径が75μm以下であり、前記温間金型潤滑成形用鉄基
粉末混合物の全量に対して、前記黒鉛粉末が0.1 〜1.0
質量%であり、前記粉末成形用潤滑剤が0.05〜0.40質量
%であることを特徴とする温間金型潤滑成形用鉄基粉末
混合物である。前記鉄基粉末を、最大粒径が75μm以下
の1次粒子を造粒した2次粒子とし、該2次粒子の最大
粒径を180 μm 以下としてなることが好ましい。The present invention also provides an iron-based powder mixture for warm die lubrication molding, comprising an iron-based powder, a graphite powder, and a lubricant for powder molding, the maximum particle size of the primary particles of the iron-based powder. Is 75 μm or less, and the graphite powder is 0.1 to 1.0 with respect to the total amount of the iron-based powder mixture for warm die lubrication molding.
%, And the lubricant for powder molding is 0.05 to 0.40 mass%, which is an iron-based powder mixture for warm die lubrication molding. It is preferable that the iron-based powder is a secondary particle obtained by granulating primary particles having a maximum particle size of 75 μm or less, and the maximum particle size of the secondary particle is 180 μm or less.
【0011】さらに本発明は、金型に、加熱した鉄基粉
末混合物を充填した後、所定の温度で加圧成形して鉄基
粉末成形体とし、ついで、該鉄基粉末成形体に焼結処理
を施し鉄基焼結体とする鉄基焼結体の製造方法におい
て、前記金型を、予熱された金型とし、前記鉄基粉末混
合物が、1次粒子の最大粒径が75μm以下の鉄基粉末
と、前記温間成形用鉄基粉末混合物の全量に対して、0.
1 〜1.0 質量%の黒鉛粉末と、0.05〜0.80質量%の粉末
成形用潤滑剤とを含有することを特徴とする鉄基焼結体
の製造方法である。また、本発明は、金型に、加熱した
鉄基粉末混合物を充填した後、所定の温度で加圧成形し
て鉄基粉末成形体とし、ついで、該鉄基粉末成形体に焼
結処理を施し鉄基焼結体とする鉄基焼結体の製造方法に
おいて、前記金型を、予熱され、表面に温間金型潤滑用
潤滑剤を帯電付着させた金型とし、前記鉄基粉末混合物
が、1次粒子の最大粒径が75μm以下の鉄基粉末と、前
記鉄基粉末混合物の全量に対して、0.1 〜1.0 質量%の
黒鉛粉末と、0.05〜0.40質量%の粉末成形用潤滑剤とを
含有することを特徴とする鉄基焼結体の製造方法であ
る。上記の鉄基焼結体の製造方法において、前記鉄基粉
末を、最大粒径が75μm以下の1次粒子を造粒した2次
粒子とし、該2次粒子の最大粒径を180 μm 以下として
なることが好ましい。さらに、本発明は上記の鉄基焼結
体の製造方法で製造された鉄基焼結体を、さらに熱処理
することが好ましい鉄基焼結体の製造方法である。Further, according to the present invention, a mold is filled with a heated iron-based powder mixture, and then pressure-molded at a predetermined temperature to obtain an iron-based powder molded body, and then the iron-based powder molded body is sintered. In the method for producing an iron-based sintered body, which is a treated iron-based sintered body, the mold is a preheated mold, and the iron-based powder mixture has a maximum primary particle size of 75 μm or less. With respect to the iron-based powder and the total amount of the warm-forming iron-based powder mixture, 0.
A method for producing an iron-based sintered body, comprising 1 to 1.0% by mass of graphite powder and 0.05 to 0.80% by mass of a lubricant for powder molding. Further, the present invention, after filling the mold with the heated iron-based powder mixture, pressure-molded at a predetermined temperature to form an iron-based powder molded body, and then subjecting the iron-based powder molded body to a sintering treatment. In the method for producing an iron-based sintered body, which is a cast iron-based sintered body, the mold is a mold preheated, and a lubricant for warm mold lubrication is electrostatically adhered to the surface, and the iron-based powder mixture is used. Is an iron-based powder having a maximum primary particle size of 75 μm or less, 0.1 to 1.0% by mass of graphite powder, and 0.05 to 0.40% by mass of a lubricant for powder molding, based on the total amount of the iron-based powder mixture. The method for producing an iron-based sintered body is characterized by containing and. In the method for producing an iron-based sintered body, the iron-based powder is a secondary particle obtained by granulating primary particles having a maximum particle size of 75 μm or less, and the maximum particle size of the secondary particle is 180 μm or less. It is preferable that Further, the present invention is a method for producing an iron-based sintered body, which is preferable to further heat-treat the iron-based sintered body produced by the above-described method for producing an iron-based sintered body.
【0012】[0012]
【発明の実施の形態】まず、本発明に係る温間成形技術
について説明する。この温間成形技術は、予熱された金
型内に鉄基粉末混合物を充填し、該鉄基粉末混合物を所
定の温度で加圧成形し、鉄基粉末成形体とする方法であ
る。その際、加圧成形に用いる金型は予め所定の温度に
予熱しておく。金型の予熱温度は、加圧成形中、鉄基粉
末混合物が所定の加圧成形温度に保持できるような温度
であればよい。本発明で言う所定の加圧成形温度とは、
鉄基粉末混合物の温度をいうものとする。BEST MODE FOR CARRYING OUT THE INVENTION First, a warm forming technique according to the present invention will be described. This warm molding technique is a method of filling an iron-based powder mixture in a preheated mold and press-molding the iron-based powder mixture at a predetermined temperature to obtain an iron-based powder compact. At this time, the mold used for pressure molding is preheated to a predetermined temperature. The preheating temperature of the mold may be any temperature at which the iron-based powder mixture can be maintained at a predetermined pressure molding temperature during pressure molding. The predetermined pressure molding temperature referred to in the present invention is
It refers to the temperature of the iron-based powder mixture.
【0013】鉄基粉末混合物の加熱温度は、70〜200 ℃
とするのが好ましく、さらに100 〜160 ℃とするのがよ
り好ましい。鉄基粉末混合物の加熱温度が70℃未満で
は、鉄粉の降伏応力が高く、成形体の密度が低下し、一
方、鉄基粉末混合物の加熱温度が200 ℃を超えても実質
的に密度の増加はなく、鉄基粉末の酸化の懸念が生じ
る。The heating temperature of the iron-based powder mixture is 70 to 200 ° C.
The temperature is preferably set to 100 to 160 ° C., and more preferably set to 100 to 160 ° C. If the heating temperature of the iron-based powder mixture is lower than 70 ° C, the yield stress of the iron powder is high and the density of the compact is lowered, while if the heating temperature of the iron-based powder mixture exceeds 200 ° C, the density of the There is no increase, and there is concern about oxidation of the iron-based powder.
【0014】このために、鉄基粉末混合物の加熱温度は
70〜200 ℃の範囲とするのが望ましい。鉄基粉末混合物
は、鉄基粉末に、黒鉛と、粉末成形用潤滑剤、あるいは
さらに銅粉などの合金粉末を混合したものである。鉄基
粉末と黒鉛、粉末成形用潤滑剤、あるいはさらに合金粉
末との混合方法は、特に限定する必要はなく、通常の公
知の混合方法で行う。For this reason, the heating temperature of the iron-based powder mixture is
It is desirable that the temperature range is 70 to 200 ° C. The iron-based powder mixture is obtained by mixing iron-based powder with graphite, a lubricant for powder molding, or an alloy powder such as copper powder. The method of mixing the iron-based powder with the graphite, the powder molding lubricant, or the alloy powder is not particularly limited, and a usual known mixing method is used.
【0015】本発明の鉄基粉末混合物に含まれる粉末成
形用潤滑剤の含有量は、鉄基粉末混合物全量に対し0.05
〜0.80質量%とする。粉末成形用潤滑剤の含有量が0.05
質量%未満では、鉄基粉末混合物の粒子同士の潤滑作用
が少なくなり、成形体の密度が低下し、また、成形割れ
が生じやすい。一方、粉末成形用潤滑剤含有量が0.80質
量%を超えると、潤滑作用よりむしろ粒子の塑性変形を
阻害するように働くため成形体の密度が低下し、焼結体
密度が低下する。The content of the lubricant for powder molding contained in the iron-based powder mixture of the present invention is 0.05 based on the total amount of the iron-based powder mixture.
~ 0.80 mass%. Content of lubricant for powder molding is 0.05
If it is less than mass%, the lubricating effect between the particles of the iron-based powder mixture is reduced, the density of the molded body is lowered, and molding cracks are likely to occur. On the other hand, if the content of the lubricant for powder compaction exceeds 0.80 mass%, the density of the compact decreases because it acts not to lubricate but to inhibit the plastic deformation of the particles, and the density of the sintered compact decreases.
【0016】鉄基粉末混合物に配合される粉末成形用潤
滑剤としては、特公平7-103404号公報、特開平9-104901
号公報、特開平10-317001 号公報に示された潤滑剤がい
ずれも好適に使用できる。また、ステアリン酸亜鉛、ス
テアリン酸リチウム、ステアリン酸カルシウム等の金属
石鹸や、エチレンビスステアロアミド等の通常ワックス
と呼ばれる潤滑剤が単独あるいは混合して使用できる。As a powder molding lubricant to be blended with the iron-based powder mixture, Japanese Patent Publication No. 7-103404 and JP-A-9-104901 are available.
Any of the lubricants disclosed in JP-A-10-317001 and JP-A-10-317001 can be preferably used. Further, metal soaps such as zinc stearate, lithium stearate and calcium stearate, and lubricants usually called wax such as ethylene bisstearamide can be used alone or in combination.
【0017】鉄基粉末混合物に含まれる黒鉛は、焼結体
中に拡散し、固溶強化によって焼結体を強化する効果を
有する。鉄基粉末混合物に含まれる黒鉛量が1.0 質量%
を超えると成形体の密度が低下する。一方、含有する黒
鉛量が0.1 質量%未満では、焼結体を強化する効果が少
ない。このため、鉄基粉末混合物中に含有される黒鉛
は、鉄基粉末混合物全量に対し、0.1 〜1.0 質量%とす
る。The graphite contained in the iron-based powder mixture has the effect of diffusing into the sintered body and strengthening the sintered body by solid solution strengthening. The amount of graphite contained in the iron-based powder mixture is 1.0% by mass.
If it exceeds, the density of the molded product will decrease. On the other hand, if the amount of graphite contained is less than 0.1% by mass, the effect of strengthening the sintered body is small. Therefore, the graphite contained in the iron-based powder mixture is 0.1 to 1.0 mass% with respect to the total amount of the iron-based powder mixture.
【0018】ここで、本発明に用いる鉄基粉末は、1次
粒子の最大粒径を75μm以下に限定する。鉄基粉末中に
1次粒子の粒径が75μmを超えるものが含まれている
と、焼結の駆動力が弱くなり、75μmを超えた1次粒径
の鉄基粉末の周囲に粗大な空孔が形成されてしまう。ま
た、鉄基粉末中に1次粒子の粒径が75μmを超えるもの
が含まれていると、鉄基粉末混合物を加圧成形して得た
成形体の焼結時に、75μmを超えた1次粒径の鉄基粉末
の中心にまで合金元素が十分拡散せず、鉄基焼結体にさ
らに強度を高めるための熱処理、例えば、ガス浸炭焼入
れ、光輝焼入れ、高周波焼入れなどを施す際に、焼入性
が低くなり、粗大な比較的柔らかいフェライト組織ある
いはパーライト組織になってしまう。これらの粗大空孔
および粗大な柔らかい組織はいずれも疲労破壊の起点と
なりやすいため、疲労強度が低下する。また、1次粒子
の最大粒径が75μm以下の鉄基粉末を用い、これを造粒
することにより2次粒子を製造し、見かけの粒径を大き
くすることによって、鉄基粉末や鉄基粉末混合物の流動
性を改善することができ、金型への充填性や寸法のばら
つきを改善することができる。この鉄基粉末を用いた焼
結体の機械的特性は、1次粒子の最大粒径に依存するた
め、造粒しない場合と比べ、疲労強度は低下しない。2
次粒子最大粒径は、180 μm を超えると薄肉場所への充
填性が低下するため、180 μm 以下が好適である。1次
粒子を造粒して2次粒子を製造する方法については、公
知の方法を用いることができ、加熱して造粒しても良い
し、バインダで造粒しても良い。鉄基粉末は、アトマイ
ズした純鉄粉、部分拡散合金化鋼粉、完全合金化鋼粉、
またはこれらの混合粉とするのが好ましい。特に好まし
くは部分拡散合金化粉および/または完全合金化鋼粉で
あり、合金化成分としてはNi、Cu、およびMoから選ばれ
る1種または2種以上である。In the iron-based powder used in the present invention, the maximum particle size of primary particles is limited to 75 μm or less. If the iron-based powder contains primary particles with a particle size of more than 75 μm, the driving force for sintering will be weakened, and coarse voids will be present around the iron-based powder with a primary particle size of more than 75 μm. Holes will be formed. Further, when the iron-based powder contains primary particles having a particle size of more than 75 μm, the primary product having a particle size of more than 75 μm was obtained during sintering of the molded body obtained by press-molding the iron-based powder mixture. The alloying elements do not sufficiently diffuse to the center of the iron-based powder having a particle size, and heat treatment for further strengthening the iron-based sintered body, for example, when performing gas carburizing quenching, bright quenching, induction hardening, etc. Poor penetrability results in a coarse and relatively soft ferrite structure or pearlite structure. Since both of these coarse pores and coarse soft structures easily become the starting points of fatigue fracture, the fatigue strength is reduced. Further, iron-based powder having a maximum primary particle size of 75 μm or less is used, and secondary particles are produced by granulating the iron-based powder to increase the apparent particle size. The fluidity of the mixture can be improved, and the filling property in the mold and the dimensional variation can be improved. Since the mechanical properties of the sintered body using this iron-based powder depend on the maximum particle size of the primary particles, the fatigue strength does not decrease as compared with the case where no granulation is performed. Two
If the maximum particle size of secondary particles exceeds 180 μm, the filling property into thin-walled areas will be reduced, so 180 μm or less is preferable. As a method for granulating the primary particles to produce the secondary particles, a known method may be used, and the particles may be granulated by heating or may be granulated with a binder. Iron-based powders are atomized pure iron powder, partially diffused alloyed steel powder, fully alloyed steel powder,
Alternatively, a mixed powder of these is preferable. Particularly preferred are partially diffused alloyed powder and / or fully alloyed steel powder, and the alloying component is one or more selected from Ni, Cu, and Mo.
【0019】なお、1次粒子の最大粒径が75μm以下の
鉄基粉末は、篩で順にふるって分級していき、JIS Z880
1 75μm の篩(200 メッシュ)を通過した粉末を用いる
か、あるいはさらに、JIS Z8801 75μm の篩よりも篩目
の細かい篩を通過した粉末を用いればよい。もしくは、
最大粒径が75μm以下の鉄基粉末としては、例えば、JI
S Z8801 75μm の篩(200 メッシュ)を通過した粉末
で、かつJIS Z8801 63μm の篩(250 メッシュ)を通過
しない粉末を−75/+63粉末とし、JIS Z8801 63μ
m の篩(250 メッシュ)を通過した粉末で、かつJIS Z8
801 45μm の篩(325 メッシュ)を通過しない粉末を−
63/+45粉末とした場合、−75/+63粉末と−
63/+45粉末とを適宜な割合で混合し、粒度分布を
調整したものとすることもできる。2次粒子についても
同様な方法で粒度分布を調整する。例えば、JIS Z8801
180 μm の篩(80メッシュ)を通過した粉末を用いる。The iron-based powder having a maximum primary particle size of 75 μm or less is classified by sieving with a sieve in order.
Powder that has passed through a 75 μm sieve (200 mesh) or powder that has passed through a sieve with a finer mesh than JIS Z8801 75 μm sieve may be used. Or
As an iron-based powder having a maximum particle size of 75 μm or less, for example, JI
S Z8801 75μm sieve (200mesh) powder that does not pass JIS Z8801 63μm sieve (250mesh) powder is -75 / + 63 powder, JIS Z8801 63μ
Powder that has passed through a m sieve (250 mesh) and JIS Z8
801 Powder that does not pass through a 45 μm sieve (325 mesh)
63 / + 45 powder is -75 / + 63 powder and-
63 / + 45 powder may be mixed at an appropriate ratio to adjust the particle size distribution. The particle size distribution of secondary particles is adjusted in the same manner. For example, JIS Z8801
Use the powder that has passed through a 180 μm sieve (80 mesh).
【0020】次いで、本発明に係る温間金型潤滑成形技
術について説明する。温間金型潤滑成形は、予熱された
金型の内面に帯電した潤滑剤を塗布し、潤滑剤が塗布さ
れた金型内に鉄基粉末混合物を充填し、該鉄基粉末混合
物を所定の温度で加圧成形し、鉄基粉末成形体とする方
法である。その際、加圧成形に用いる金型は予め所定の
温度に予熱しておく。金型の予熱温度は、加圧成形中、
鉄基粉末混合物が所定の加圧成形温度に保持できるよう
な温度であればよい。本発明で言う所定の加圧成形温度
とは、鉄基粉末混合物の温度をいうものとする。Next, the warm die lubrication molding technique according to the present invention will be described. Warm die lubrication molding involves applying a charged lubricant to the inner surface of a preheated die, filling the iron-based powder mixture in the die to which the lubricant has been applied, and then applying the iron-based powder mixture to a predetermined amount. This is a method of pressing at a temperature to obtain an iron-based powder compact. At this time, the mold used for pressure molding is preheated to a predetermined temperature. The preheating temperature of the mold is
Any temperature may be used as long as the iron-based powder mixture can be maintained at a predetermined pressure molding temperature. The predetermined pressure molding temperature referred to in the present invention means the temperature of the iron-based powder mixture.
【0021】予熱された金型の内面に、帯電された金型
潤滑剤を塗布し、金型の内面に金型潤滑用潤滑剤を帯電
付着させるには、金型潤滑装置(例えば、Gasbarre社製
のDie Wall Lubricant System )を用いることができ
る。この金型潤滑装置を用いて金型潤滑用潤滑剤を塗布
するには、金型潤滑装置に金型潤滑用潤滑剤の固体粉末
を装入し、金型潤滑用潤滑剤の固体粉末と装置内壁との
接触帯電により、金型潤滑用潤滑剤を帯電し、帯電され
た金型潤滑用潤滑剤を金型内面に噴射することにより、
金型内面に金型潤滑用潤滑剤を帯電付着させることがで
きる。金型内面に帯電付着させる金型潤滑用潤滑剤の付
着量は5〜100g/m2 とするのが好ましい。金型潤滑用潤
滑剤の付着量が5g /m2 未満では潤滑効果が不足し、成
形後の抜き出し力が高くなり、金型潤滑用潤滑剤の付着
量が100g/m2 を超えると、抜き出した成形体表面に金型
潤滑用潤滑剤が残存し、成形体の外観不良となる。In order to apply a charged mold lubricant to the inner surface of the preheated mold and charge the lubricant for mold lubrication to the inner surface of the mold, a mold lubricator (for example, Gasbarre Company) is used. Manufactured by Die Wall Lubricant System) can be used. To apply the lubricant for mold lubrication using this mold lubricator, the solid powder of the lubricant for mold lubrication is loaded into the mold lubricator, and the solid powder of the lubricant for mold lubrication and the device are applied. By contact charging with the inner wall, the lubricant for mold lubrication is charged, and the charged lubricant for lubricant for mold is sprayed on the inner surface of the mold,
A lubricant for die lubrication can be electrostatically attached to the inner surface of the die. The amount of the lubricant for die lubrication to be electrostatically adhered to the inner surface of the die is preferably 5 to 100 g / m 2 . If the amount of lubricant for mold lubrication is less than 5 g / m 2 , the lubrication effect will be insufficient and the extraction force after molding will be high. If the amount of lubricant for mold lubrication exceeds 100 g / m 2, it will be extracted. The lubricant for mold lubrication remains on the surface of the molded body, resulting in poor appearance of the molded body.
【0022】金型潤滑用潤滑剤としては、ステアリン酸
亜鉛、ステアリン酸リチウム、ステアリン酸カルシウム
等の金属石鹸や、エチレンビスステアロアミド等の通常
ワックスと呼ばれる潤滑剤を単独、あるいは混合して使
用できる。ついで、金型潤滑用潤滑剤を帯電付着された
金型内に、加熱された鉄基粉末混合物を装入し、加圧成
形し、鉄基粉末成形体とする。As the lubricant for die lubrication, metal soaps such as zinc stearate, lithium stearate and calcium stearate, and lubricants usually called wax such as ethylene bis-stearamide can be used alone or in combination. . Then, the heated iron-based powder mixture is charged into a mold to which a lubricant for die lubrication has been electrified and pressure-molded to obtain an iron-based powder compact.
【0023】鉄基粉末混合物の加熱温度は、70〜200 ℃
とするのが好ましく、さらに100 〜160 ℃とするのがよ
り好ましい。鉄基粉末混合物の加熱温度が70℃未満で
は、鉄粉の降伏応力が高く、成形体の密度が低下し、一
方、鉄基粉末混合物の加熱温度が 200℃を超えても実質
的に密度の増加はなく、鉄基粉末の酸化の懸念が生じ
る。このため、鉄基粉末混合物の加熱温度は70〜200 ℃
の範囲とするのが望ましい。The heating temperature of the iron-based powder mixture is 70 to 200 ° C.
The temperature is preferably set to 100 to 160 ° C., and more preferably set to 100 to 160 ° C. If the heating temperature of the iron-based powder mixture is less than 70 ° C, the yield stress of the iron powder is high, and the density of the compact decreases, while if the heating temperature of the iron-based powder mixture exceeds 200 ° C, the density of the There is no increase, and there is concern about oxidation of the iron-based powder. Therefore, the heating temperature of the iron-based powder mixture is 70 to 200 ° C.
It is desirable to set the range to.
【0024】鉄基粉末混合物は、鉄基粉末に、黒鉛と、
粉末成形用潤滑剤、あるいはさらに銅粉などの合金粉末
を混合したものである。鉄基粉末と黒鉛、粉末成形用潤
滑剤、あるいはさらに合金粉末との混合方法は、特に限
定する必要はなく、通常の公知の混合方法で行う。鉄基
粉末の1次粒子の最大粒径は75μm以下である。鉄基粉
末の最大粒径を75μmに限定する理由、鉄基粉末の種類
および調整方法、黒鉛の含有量および限定理由は温間成
形技術で説明した通りである。また2次粒子最大粒径は
180 μm 以下が好適である。この理由は温間成形技術で
説明した通りである。The iron-based powder mixture contains iron-based powder, graphite, and
A lubricant for powder molding, or an alloy powder such as copper powder is further mixed. The method of mixing the iron-based powder with the graphite, the powder molding lubricant, or the alloy powder is not particularly limited, and a usual known mixing method is used. The maximum particle size of the primary particles of the iron-based powder is 75 μm or less. The reason why the maximum particle size of the iron-based powder is limited to 75 μm, the type and adjusting method of the iron-based powder, the graphite content and the reason for the limitation are as described in the warm forming technique. The maximum secondary particle size is
180 μm or less is preferable. The reason for this is as explained in the warm forming technique.
【0025】温間金型潤滑成形に用いる場合の粉末成形
用潤滑剤の種類は温間成形技術で説明したものと同じも
のが使用できる。なお、温間金型潤滑成形用鉄基粉末混
合物に含まれる粉末成形用潤滑剤の含有量は、鉄基粉末
混合物全量に対し、0.05〜0.40質量%である。粉末成形
用潤滑剤の含有量が0.05質量%未満では、鉄基粉末混合
物の粒子同士の潤滑作用が少なくなり、成形体の密度が
低下し、また、成形割れが生じやすい。一方、温間金型
潤滑成形の場合は、粉末成形用潤滑剤含有量が0.40質量
%を超えると、潤滑作用は飽和し、むしろ粒子の塑性変
形を阻害するように働くため成形体の密度が低下し、焼
結体密度が低下する。The type of the lubricant for powder molding used in the warm die lubrication molding can be the same as that described in the warm molding technique. The content of the lubricant for powder molding contained in the iron-based powder mixture for warm die lubrication molding is 0.05 to 0.40 mass% with respect to the total amount of the iron-based powder mixture. When the content of the powder molding lubricant is less than 0.05% by mass, the lubricating effect of the particles of the iron-based powder mixture is reduced, the density of the molded product is lowered, and molding cracks are likely to occur. On the other hand, in the case of warm die lubrication molding, if the content of the lubricant for powder molding exceeds 0.40 mass%, the lubricating action is saturated, and rather the density of the compact is reduced because it acts to inhibit the plastic deformation of the particles. And the density of the sintered body decreases.
【0026】また、本発明では、上記の温間成形技術ま
たは温間金型潤滑成形技術を用いて製造された高密度の
鉄基粉末成形体に、焼結処理を施し鉄基焼結体を得る。
本発明における焼結処理条件は、特に限定する必要はな
く、通常公知の焼結方法がいずれも好適に使用できる。
焼結温度は、1100〜1300℃の範囲とするのが好ましく、
焼結雰囲気は、エンドサーミックガス雰囲気(RX雰囲
気)、水素を含む窒素ガス雰囲気、あるいはアンモニア
分解ガス雰囲気、あるいは真空中とするのが好ましい。
なお、焼結温度が高いほど焼結体強度は増加するが、焼
結温度の上昇は、焼結コストを増加させるため、焼結温
度は強度とコストを考慮して適宜選択するのが好まし
い。In the present invention, a high-density iron-based powder compact produced by the warm compaction technique or the warm die lubrication compaction technique is subjected to a sintering treatment to obtain an iron-based sintered compact. obtain.
The sintering treatment conditions in the present invention are not particularly limited, and any commonly known sintering method can be preferably used.
The sintering temperature is preferably in the range of 1100 to 1300 ° C,
The sintering atmosphere is preferably an end-thermic gas atmosphere (RX atmosphere), a nitrogen gas atmosphere containing hydrogen, an ammonia decomposition gas atmosphere, or a vacuum.
The higher the sintering temperature is, the higher the strength of the sintered body is. However, since the increase of the sintering temperature increases the sintering cost, it is preferable to appropriately select the sintering temperature in consideration of the strength and the cost.
【0027】本発明では、上記のようにして得た鉄基焼
結体に、さらに疲労強度を高めるため、熱処理を施すこ
とが好ましい。熱処理は、ガス浸炭焼入れ、光輝焼入
れ、高周波焼入れなど公知の熱処理を施すことができ
る。In the present invention, the iron-based sintered body obtained as described above is preferably subjected to a heat treatment in order to further increase the fatigue strength. As the heat treatment, known heat treatments such as gas carburizing quenching, bright quenching, and induction hardening can be performed.
【0028】[0028]
【実施例】(実施例1〜3、比較例1、2)鉄基粉末と
して、Fe-4Ni-0.5Mo-1.5Cu組成の部分合金化鋼粉を用い
た。部分合金化鋼粉は、篩により分級して最大粒径を変
えたアトマイズ純鉄粉を1次粒子とし、Ni、Mo、Cuを混
合して加熱処理により拡散付着させると同時に、2次粒
子に造粒し、篩により所定の粒径に分級して得たもので
ある。これらの各部分合金化鋼粉に、表1に示す量の粉
末成形用潤滑剤としてのエチレンビスステアロアミド
と、黒鉛とをVブレンダで混合し、鉄基粉末混合物とし
た。[Examples] (Examples 1 to 3, Comparative Examples 1 and 2) As an iron-based powder, a partially alloyed steel powder having a composition of Fe-4Ni-0.5Mo-1.5Cu was used. Partially alloyed steel powder is atomized pure iron powder that has been classified by a sieve to change the maximum particle size as primary particles, and Ni, Mo, and Cu are mixed and diffused and adhered by heat treatment, while at the same time becoming secondary particles. It is obtained by granulating and classifying to a predetermined particle size with a sieve. Each of these partially alloyed steel powders was mixed with an amount of ethylenebisstearamide as a lubricant for powder molding shown in Table 1 and graphite with a V blender to obtain an iron-based powder mixture.
【0029】まず、加圧成形用の金型を予熱し、つい
で、この金型内に加圧成形温度に加熱した上記の鉄基粉
末混合物を充填した後、686 MPa の圧力で加圧成形し、
長さ80mm×巾15mm×高さ15mmの成形体とした。得られた
成形体に N2-10vol %H2雰囲気中で1250℃、3600s の焼
結処理を施し、鉄基焼結体とした。これら鉄基焼結体を
平行部径8mm、平行部長さ15.4mmに機械加工した。機械
加工した焼結体を、熱処理として、900 ℃、3600s で光
輝熱処理し、60℃の油中に焼入れし、180 ℃、3600s の
焼戻しを施した。該熱処理した焼結体について、回転曲
げ疲労試験(JISZ 2274)を行い、回転曲げ疲労強度を
測定した。なお、加圧成形後、成形体を抜き出す時の抜
き出し力を測定するとともに、得られた成形体の外観を
目視観察して、疵、欠け等の欠陥の有無を調査した。ま
た、得られた成形体および焼結体について、アルキメデ
ス法で密度を測定した。アルキメデス法とは、被測定物
をエタノール中に浸漬して体積を測定することにより、
密度を測定する方法である。また、熱処理後の焼結体に
ついて、中央部で切断し、樹脂に埋め込んで研磨し断面
における空孔の有無および組織を光学顕微鏡で観察し
た。比較例1、2として、最大粒径が本発明の範囲を外
れるアトマイズ純鉄粉を用いた以外は、実施例1と同じ
条件で製造した成形体と焼結体を用いた。これらの結果
を表1に示す。First, a pressure-molding die is preheated, and then the above-mentioned iron-based powder mixture heated to a pressure-forming temperature is filled into the die, and then pressure-molding is performed at a pressure of 686 MPa. ,
A molded body having a length of 80 mm, a width of 15 mm and a height of 15 mm was prepared. The obtained molded body was subjected to a sintering treatment at 1250 ° C. for 3600 s in an N 2 -10vol% H 2 atmosphere to obtain an iron-based sintered body. These iron-based sintered bodies were machined to a parallel part diameter of 8 mm and a parallel part length of 15.4 mm. As a heat treatment, the machined sintered body was brightly heat-treated at 900 ° C for 3600s, quenched in oil at 60 ° C, and tempered at 180 ° C for 3600s. A rotary bending fatigue test (JIS Z 2274) was performed on the heat-treated sintered body to measure the rotary bending fatigue strength. After the pressure molding, the extraction force at the time of extracting the molded product was measured, and the appearance of the obtained molded product was visually observed to examine the presence or absence of defects such as flaws and chips. In addition, the density of the obtained molded body and sintered body was measured by the Archimedes method. The Archimedes method is by immersing the measured object in ethanol and measuring the volume,
This is a method of measuring density. Further, the sintered body after the heat treatment was cut at the center, embedded in a resin and polished, and the presence or absence of pores and the structure in the cross section were observed with an optical microscope. As Comparative Examples 1 and 2, molded bodies and sintered bodies manufactured under the same conditions as in Example 1 were used, except that atomized pure iron powder having a maximum particle size outside the range of the present invention was used. The results are shown in Table 1.
【0030】[0030]
【表1】 [Table 1]
【0031】表1の結果から本発明による焼結体は、比
較例の焼結体より高密度で、かつ高い回転曲げ疲労強度
を有していることがわかる。
(実施例4、比較例3)鉄基粉末として、Fe-4Ni-0.5Mo
-1.5Cu組成の部分合金化鋼粉を用いた。部分合金化鋼粉
は、実施例1と同様にして節により分級して最大粒径を
変えたアトマイズ純鉄粉に、Ni、Mo、Cuをそれぞれ拡散
付着させて得たものである。これらの各部分合金化鋼粉
に、表1に示す量の粉末成形用潤滑剤としてのエチレン
ビスステアロアミドと、黒鉛とをVブレンダで混合し、
鉄基粉末混合物とした。From the results shown in Table 1, it can be seen that the sintered body according to the present invention has higher density and higher rotational bending fatigue strength than the sintered body of the comparative example. (Example 4, Comparative Example 3) Fe-4Ni-0.5Mo was used as the iron-based powder.
Partially alloyed steel powder with -1.5Cu composition was used. The partially alloyed steel powder is obtained by diffusing and adhering Ni, Mo, and Cu to atomized pure iron powder classified according to the same method as in Example 1 and having a different maximum particle size. Each of these partially alloyed steel powders was mixed with an amount of ethylene bisstearamide as a lubricant for powder molding shown in Table 1 and graphite in a V blender,
It was an iron-based powder mixture.
【0032】まず、加圧成形用の金型を予熱し、Gassba
rre 社製の金型潤滑装置を用いて帯電させた温間金型潤
滑用潤滑剤としてのステアリン酸亜鉛(ZnSt)を金型内
に噴霧し、金型の内面に帯電付着させた。なお、温間金
型潤滑用潤滑剤の付着量は10g/m2とした。ついで、この
ように処理された金型内に加圧成形温度に加熱した上記
の鉄基粉末混合物を充填した後、686MPaの圧力で加圧成
形し、長さ80mm×巾15mm×高さ15mmの成形体とした。得
られた成形体にN2-10 %H2雰囲気中で1250℃、3600S の
焼結処理を施し、鉄基焼結体とした。これら鉄基焼結体
を平行部径8mm、平行部長さ15.4mmに機械加工し、回転
曲げ疲労試験(JIS Z 2274)を行い、回転曲げ疲労度を
測定した。なお、加圧成形後、成形体を抜き出す時の抜
き出し方を測定するとともに、得られた成形体の外観を
目視観察して、庇、欠け等の欠陥の有無を調査した。ま
た、得られた成形体および焼結体について、アルキメデ
ス法で密度を測定した。First, the mold for pressure molding is preheated, and Gassba is used.
Zinc stearate (ZnSt) as a lubricant for warm mold lubrication, which was charged by using a mold lubricator manufactured by rre, was sprayed into the mold and electrostatically adhered to the inner surface of the mold. The amount of the lubricant for warm die lubrication adhered was 10 g / m 2 . Then, after filling the above iron-based powder mixture heated to the pressure molding temperature in the mold thus treated, pressure molding at a pressure of 686 MPa, length 80 mm × width 15 mm × height 15 mm It was a molded body. The obtained molded body was subjected to a sintering treatment at 1250 ° C. and 3600 S in an N 2 -10% H 2 atmosphere to obtain an iron-based sintered body. These iron-based sintered bodies were machined into a parallel part diameter of 8 mm and a parallel part length of 15.4 mm and subjected to a rotary bending fatigue test (JIS Z 2274) to measure the rotary bending fatigue level. After the pressure molding, the method of extracting the molded product was measured, and the appearance of the resulting molded product was visually observed to investigate the presence of defects such as eaves and chips. In addition, the density of the obtained molded body and sintered body was measured by the Archimedes method.
【0033】比較例3として、最大粒径が本発明の範囲
を外れるアトマイズ純鉄粉を用いた以外は、実施例4と
同じ条件で製造した成形体と焼結体を用いた。これらの
結果を前記表1に示す。表1の結果から本発明による焼
結体は、比較例の焼結体より高密度で、かつ高い回転曲
げ疲労強度を有していることがわかる。As Comparative Example 3, a molded body and a sintered body manufactured under the same conditions as in Example 4 were used except that atomized pure iron powder having a maximum particle size outside the range of the present invention was used. The results are shown in Table 1 above. From the results in Table 1, it is understood that the sintered body according to the present invention has a higher density and a higher rotational bending fatigue strength than the sintered body of the comparative example.
【0034】(実施例5〜12、比較例4〜8)黒鉛及び
粉末成形用潤滑剤の含有量、鉄基粉末の最大粒径、加圧
成形温度を表1の各条件とした以外は、実施例4と同様
の条件で製造した鉄基焼結体を機械加工した後、熱処理
として、900 ℃、7200s、カーボンポテンシャル0.8 %
でガス浸炭し、60℃の油中に焼入れ後、180 ℃、3600s
の焼き戻しを施した。なお、この場合、実施例1と同様
の方法で成形体および焼結体について調査を行ったが、
焼結体としては熱処理後の焼結体を用いた。比較例4、
5、6として、最大粒径が本発明の範囲を外れるアトマ
イズ純鉄粉を用いた以外は、実施例5と同じ条件で製造
した成形体と焼結体を用いた。(Examples 5 to 12, Comparative Examples 4 to 8) Except that the contents of the graphite and the lubricant for powder molding, the maximum particle size of the iron-based powder, and the pressure molding temperature were set to the respective conditions of Table 1, The iron-based sintered body produced under the same conditions as in Example 4 was machined, and then heat-treated at 900 ° C. for 7200 s and a carbon potential of 0.8%.
After carburizing with gas and quenching in oil at 60 ℃, 180 ℃, 3600s
Tempered. In this case, although the molded body and the sintered body were investigated by the same method as in Example 1,
As the sintered body, a sintered body after heat treatment was used. Comparative Example 4,
The molded bodies and sintered bodies produced under the same conditions as in Example 5 were used as 5 and 6 except that atomized pure iron powder having a maximum particle size outside the range of the present invention was used.
【0035】比較例7として、潤滑剤含有量が本発明の
範囲を外れる鉄基粉末混合物組成を用いた以外は、実施
例8と同じ条件で製造した成形体と焼結体を用いた。比
較例8として、加圧成形温度が本発明の範囲を外れる加
圧成形条件とし、表1に示す組成の鉄基粉末混合物を用
い、実施例1と同様に温間成形した成形品と、この成形
品を実施例5と同様に焼結、熱処理を施した焼結体とを
用いた。As Comparative Example 7, a molded body and a sintered body produced under the same conditions as in Example 8 were used, except that an iron-based powder mixture composition having a lubricant content outside the range of the present invention was used. As Comparative Example 8, a molded article was prepared by warm molding in the same manner as in Example 1 using a mixture of iron-based powders having the composition shown in Table 1 under the pressure molding conditions in which the pressure molding temperature was out of the range of the present invention. The molded product was used in the same manner as in Example 5, including sintering and heat treatment.
【0036】これらの結果を前記表1に示す。表1の結
果から本発明による焼結体は、比較例の焼結体より高密
度で、かつ高い回転曲げ疲労強度を有していることがわ
かる。また、実施例6、8、9で用いた鉄基粉末混合物
の流動性を調査した、その結果を表2に示す。The results are shown in Table 1 above. From the results in Table 1, it is understood that the sintered body according to the present invention has a higher density and a higher rotational bending fatigue strength than the sintered body of the comparative example. Further, the fluidity of the iron-based powder mixture used in Examples 6, 8 and 9 was investigated, and the results are shown in Table 2.
【0037】[0037]
【表2】 [Table 2]
【0038】なお、流動度は、 100gの鉄基粉末混合物
がφ5mmのオリフィスから流れ落ちる時間である。The fluidity is the time when 100 g of the iron-based powder mixture flows down from the φ5 mm orifice.
【0039】[0039]
【発明の効果】本発明によれば、高密度の成形体を1回
の成形で容易に製造でき、しかも1回の焼結で高い回転
曲げ疲労強度を有する焼結体が容易に得られるという産
業上格段の効果を奏する。EFFECTS OF THE INVENTION According to the present invention, a high-density molded body can be easily manufactured by one-time molding, and a sintered body having high rotary bending fatigue strength can be easily obtained by one-time sintering. It has a great effect on industry.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 上ノ薗 聡 千葉県千葉市中央区川崎町1番地 川崎製 鉄株式会社技術研究所内 (72)発明者 藤木 章 神奈川県横浜市神奈川区宝町2番地 日産 自動車株式会社内 (72)発明者 前川 幸広 神奈川県横浜市神奈川区宝町2番地 日産 自動車株式会社内 (72)発明者 馬渕 豊 神奈川県横浜市神奈川区宝町2番地 日産 自動車株式会社内 Fターム(参考) 4K018 AA24 AB10 AC01 BA13 BA20 BB04 BC11 BC12 CA00 CA07 CA11 DA00 FA08 KA01 ─────────────────────────────────────────────────── ─── Continued front page (72) Inventor Satoshi Kaminozono 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Made in Kawasaki Technical Research Institute of Iron Co., Ltd. (72) Inventor Akira Fujiki Nissan, Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa Nissan Inside the automobile corporation (72) Inventor Yukihiro Maekawa Nissan, Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa Nissan Inside the automobile corporation (72) Inventor Yutaka Mabuchi Nissan, Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa Nissan Inside the automobile corporation F-term (reference) 4K018 AA24 AB10 AC01 BA13 BA20 BB04 BC11 BC12 CA00 CA07 CA11 DA00 FA08 KA01
Claims (8)
滑剤とを含有する温間成形用鉄基粉末混合物において、
前記鉄基粉末の1次粒子の最大粒径が75μm以下であ
り、前記温間成形用鉄基粉末混合物の全量に対して、前
記黒鉛粉末が0.1 〜1.0 質量%であり、前記粉末成形用
潤滑剤が0.05〜0.80質量%であることを特徴とする温間
成形用鉄基粉末混合物。1. A warm-forming iron-based powder mixture containing iron-based powder, graphite powder and a powder-forming lubricant,
The maximum particle size of primary particles of the iron-based powder is 75 μm or less, the graphite powder is 0.1 to 1.0 mass% with respect to the total amount of the iron-based powder mixture for warm forming, and the lubricant for powder forming is The iron-based powder mixture for warm forming, wherein the agent is 0.05 to 0.80 mass%.
の1次粒子を造粒した2次粒子とし、該2次粒子の最大
粒径を180 μm 以下としてなることを特徴とする請求項
1記載の温間成形用鉄基粉末混合物。2. The iron-based powder is a secondary particle obtained by granulating primary particles having a maximum particle size of 75 μm or less, and the maximum particle size of the secondary particle is 180 μm or less. Item 2. An iron-based powder mixture for warm forming according to Item 1.
滑剤とを含有する温間金型潤滑成形用鉄基粉末混合物に
おいて、前記鉄基粉末の1次粒子の最大粒径が75μm以
下であり、前記温間金型潤滑成形用鉄基粉末混合物の全
量に対して、前記黒鉛粉末が0.1 〜1.0 質量%であり、
前記粉末成形用潤滑剤が0.05〜0.40質量%であることを
特徴とする温間金型潤滑成形用鉄基粉末混合物。3. An iron-based powder mixture for warm mold lubrication molding, comprising iron-based powder, graphite powder and a lubricant for powder molding, wherein the maximum particle size of primary particles of said iron-based powder is 75 μm or less. Yes, with respect to the total amount of the iron-based powder mixture for warm die lubrication molding, the graphite powder is 0.1 to 1.0 mass%,
The iron-based powder mixture for warm die lubrication molding, wherein the powder molding lubricant is 0.05 to 0.40% by mass.
の1次粒子を造粒した2次粒子とし、該2次粒子の最大
粒径を180 μm 以下としてなることを特徴とする請求項
3記載の温間金型潤滑成形用鉄基粉末混合物。4. The iron-based powder is a secondary particle obtained by granulating primary particles having a maximum particle size of 75 μm or less, and the maximum particle size of the secondary particle is 180 μm or less. Item 3. An iron-based powder mixture for warm die lubrication molding according to Item 3.
した後、所定の温度で加圧成形して鉄基粉末成形体と
し、ついで、該鉄基粉末成形体に焼結処理を施し鉄基焼
結体とする鉄基焼結体の製造方法において、前記金型
を、予熱された金型とし、前記鉄基粉末混合物が、1次
粒子の最大粒径が75μm以下の鉄基粉末と、前記鉄基粉
末混合物の全量に対して、0.1 〜1.0 質量%の黒鉛粉末
と、0.05〜0.80質量%の粉末成形用潤滑剤とを含有する
ことを特徴とする鉄基焼結体の製造方法。5. A mold is filled with a heated iron-based powder mixture, and then pressure-molded at a predetermined temperature to form an iron-based powder compact, and then the iron-based powder compact is sintered. In the method for producing an iron-based sintered body, which is an iron-based sintered body, the die is a preheated die, and the iron-based powder mixture is an iron-based powder having a maximum primary particle size of 75 μm or less. And 0.1 to 1.0% by mass of graphite powder and 0.05 to 0.80% by mass of a lubricant for powder molding, based on the total amount of the iron-based powder mixture, Method.
した後、所定の温度で加圧成形して鉄基粉末成形体と
し、ついで、該鉄基粉末成形体に焼結処理を施し鉄基焼
結体とする鉄基焼結体の製造方法において、前記金型
を、予熱され,表面に温間金型潤滑用潤滑剤を帯電付着
させた金型とし、前記鉄基粉末混合物が、1次粒子の最
大粒径が75μm以下の鉄基粉末と、前記鉄基粉末混合物
の全量に対して、0.1 〜1.0 質量%の黒鉛粉末と、0.05
〜0.40質量%の粉末成形用潤滑剤とを含有することを特
徴とする鉄基焼結体の製造方法。6. A mold is filled with a heated iron-based powder mixture, and then pressure-molded at a predetermined temperature to obtain an iron-based powder compact, and then the iron-based powder compact is sintered. In the method for producing an iron-based sintered body, which is an iron-based sintered body, the mold is a mold that is preheated and has a lubricant for warm mold lubrication electrostatically attached to the surface thereof, and the iron-based powder mixture is An iron-based powder having a maximum primary particle size of 75 μm or less, and 0.1 to 1.0% by mass of graphite powder with respect to the total amount of the iron-based powder mixture;
~ 0.40% by mass of a powder molding lubricant, and a method for producing an iron-based sintered body.
の1次粒子を造粒した2次粒子とし、該2次粒子の最大
粒径を180 μm 以下としてなることを特徴とする請求項
5または6に記載の鉄基焼結体の製造方法。7. The iron-based powder is a secondary particle obtained by granulating primary particles having a maximum particle size of 75 μm or less, and the maximum particle size of the secondary particle is 180 μm or less. Item 7. A method for manufacturing an iron-based sintered body according to Item 5 or 6.
体の製造方法で製造された鉄基焼結体を、さらに熱処理
することを特徴とする鉄基焼結体の製造方法。8. A method for producing an iron-based sintered body, which further comprises heat-treating the iron-based sintered body produced by the method for producing an iron-based sintered body according to claim 5, 6, or 7. .
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Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1440751A1 (en) * | 2003-01-17 | 2004-07-28 | Nissan Motor Company, Limited | Sintered body and production method thereof |
JP2013508558A (en) * | 2009-10-26 | 2013-03-07 | ホガナス アクチボラゲット | Iron-based powder composition |
DE102023117189A1 (en) | 2022-07-05 | 2024-01-11 | Miba Sinter Austria Gmbh | Method for producing a component from a sinter powder |
-
2002
- 2002-07-18 JP JP2002209042A patent/JP2003096533A/en active Pending
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1440751A1 (en) * | 2003-01-17 | 2004-07-28 | Nissan Motor Company, Limited | Sintered body and production method thereof |
JP2013508558A (en) * | 2009-10-26 | 2013-03-07 | ホガナス アクチボラゲット | Iron-based powder composition |
DE102023117189A1 (en) | 2022-07-05 | 2024-01-11 | Miba Sinter Austria Gmbh | Method for producing a component from a sinter powder |
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