JP3830802B2

JP3830802B2 - Sintered product manufacturing method and sintered product

Info

Publication number: JP3830802B2
Application number: JP2001325492A
Authority: JP
Inventors: 清勝津野; 勝彦矢野
Original assignee: 三菱マテリアルＰｍｇ株式会社
Priority date: 2001-10-23
Filing date: 2001-10-23
Publication date: 2006-10-11
Anticipated expiration: 2021-10-23
Also published as: JP2003129110A

Description

【０００１】
【発明の属する技術分野】
本発明は、ろう付けに適した焼結品の製造方法および焼結品に関する。
【０００２】
【従来の技術】
粉末を圧縮成形した圧粉体の焼結により製造される焼結品は、複数の粉末成形品同士あるいは溶製材を組み合わせて接合することにより、複雑な形状の部品や、部分的に異なる材料により形成された部品、複数の機能（歯車、カム、レバー等）を一体に備えた部品などの製造が可能である。このような焼結品を形成する接合技術のひとつとして、ろう付けが採用されている。
【０００３】
ろう付け時に部材同士を接合させるろう材としては、ニッケルろう等が多く用いられているが、より安価である銅をろう材として用いてコストダウンを図ることが求められている。ところが、銅はニッケルに比べて表面張力が小さくぬれ性に優れ、接合部のオープンポア（表面に通じている気孔）から粉末成形品内部にしみ込みやすい。ろう材が接合部に浸透することは接合強度の上昇につながるが、図７に示すように、ろう材１００が銅の場合はその多くが粉末成形品１０１内部に吸収されてしまい、接合部に残留しないため、部材同士を接合することが難しい。
【０００４】
【発明が解決しようとする課題】
銅ろう材を用いてのろう付けを可能にするために、粉末成形品の封孔処理、高密度化等の技術により、溶融された銅ろう材を接合部に残留させることが検討されている。しかしながら銅溶浸による封孔処理は、粉末成形品全体のオープンポアを埋めなければ銅ろう材の吸収を防ぐことが困難であるため、原料費が増大するという問題がある。また、水蒸気処理や樹脂含浸のような封孔処理は、工程の増加により生産コストが増大するという問題がある。
【０００５】
一方、気孔が少ない高密度の圧粉体を製造する高加圧成形は、加圧能力が大きな成形プレスが必要であり、また金型破損のおそれも大きく、製造コストが高くなるという問題がある。また、焼結温度を高くして液相焼結による気孔のクローズドポア（表面に通じていない気孔）化も可能ではあるが、処理量が少なく設備費がかかるためコストが増大するだけでなく、高温で焼結し、冷却時間が長くなると結晶粒が大きくなり、焼結品の強度が低下するという問題がある。
【０００６】
本発明は、このような問題点に鑑みてなされたもので、銅をろう材として確実なろう付けが可能な焼結品を、高加圧成形や高温での焼結によらず、低コストで得ることを目的とする。
【０００７】
【課題を解決するための手段】
記課題を解決するために、請求項１の発明に係る焼結品の製造方法は、Ｆｅ粉末とＦｅ−Ｐ合金粉末との混合粉末を、圧縮成形して圧粉体を形成し、該圧粉体を、Ｆｅ−Ｐ合金の溶融点を超えＦｅの溶融点より低い焼結温度で、Ｆｅ粉末部分を溶融させずに、Ｆｅ−Ｐ合金粉末部分を溶融させて前記Ｆｅ粉末部分の空隙部に浸透させて焼結し、密度７．２〜７．５ｇ／ｃｍ ^３、有効多孔率２％以下のろう付け用の焼結品を得ることを特徴としている。
この発明の製造方法によれば、焼結温度よりも溶融点が低い（１０５０℃）Ｆｅ−Ｐ合金粉末部分は溶融し、焼結温度よりも溶融点が高い（１５３９．６℃）Ｆｅ粉末部分は溶融しないので、液相が部分的に生じ、強度を保持しつつ、有効多孔率の低い焼結品を、高加圧成形や高温焼結によらず、低コストで製造することができる。このようにして得られた焼結品は、オープンポアが少ないため、ろう材として用いたＣｕを過剰に吸収することなく、Ｃｕのろう付けによる接合が可能となる。
【０００８】
請求項２の発明に係る焼結品の製造方法は、請求項１の焼結品の製造方法において、Ｆｅ−Ｐ合金粉末が、５〜１５重量％のＰを含有することを特徴としている。
この発明によれば、Ｆｅ−Ｐ合金が、Ｆｅの溶融点を下げるのにもっとも効果的な比率でＰを含有することにより、低い溶融点温度（１０５０℃）となるので、Ｆｅ粉末部分とＦｅ−Ｐ合金粉末部分の溶融点の差が大きく、確実に液相焼結を行うことができ、オープンポアが少なくろう付けに適した焼結品を製造することが可能となる。
【０００９】
請求項３の発明に係る焼結品の製造方法は、請求項１または２の焼結品の製造方法において、混合粉末が、０．２〜０．８重量％のＰを含有することを特徴としている。
この発明によれば、焼結品全体に対するＰの重量％を低く抑えているので、焼結品の形状を保って焼結処理を行うことができ、形状精度の優れた焼結品を製造することが可能となる。
【００１０】
請求項４の発明に係る焼結品の製造方法は、請求項１から３の焼結品の製造方法において、焼結品が、焼結温度が１１００〜１１５０℃の状態で１０分間以上保持されることを特徴としている。
この発明によれば、圧粉体全体を所定温度で一定時間保持することにより、オープンポアが少なくＣｕろう付けに適した焼結品を、確実に製造することができる。
【００１１】
請求項５の発明に係る焼結品は、Ｆｅ粉末とＦｅ−Ｐ合金粉末との混合粉末から形成された密度７．２〜７．５ｇ／ｃｍ ^３、有効多孔率２％以下の焼結品であって、前記Ｆｅ粉末の粒子が互いに結合して形成されたＦｅ部と、溶融して前記Ｆｅ粉末の粒子間の空隙部に浸透した後冷却されて前記空隙部において固化したＦｅ−Ｐ合金部とを有し、ろう付けに用いられることを特徴としている。
この発明によれば、通常の密度の焼結品でありながら、オープンポアが少なくて有効多孔率が低いので、ろう付けにおいてＣｕをろう材として用いてもＣｕが過剰に吸収されない、Ｃｕろう材によるろう付けが可能な焼結品が実現される。
【００１２】
【発明の実施の形態】
以下、本発明の実施形態について、図を参照して説明する。
図１は、本発明による焼結品１０と、溶製材からなるパイプ２０とを、ろう付けにより接合してなる機械部品３０を示す断面図である。焼結品１０はＦｅ−Ｐ合金からなる密度約７．３ｇ／ｃｍ ^３、有効多孔率約１．０％のリング状部材であり、この焼結品１０と、純Ｃｕ粉末の圧粉体からなるリング状のろう材Ｗとがパイプ２０に嵌められた状態で加熱されることにより、パイプ２０と焼結品１０とが接合されている。
【００１３】
ここで焼結品１０の製造方法について説明する。
まず、図２に示すように、Ｆｅ粉末、Ｆｅ−５〜１５％Ｐ合金粉末および潤滑剤を混合機Ｍにより混合し、Ｐを０．６質量％含む鉄系の混合粉末ｍを製造する。Ｐは、Ｆｅの溶融点を低下させるための成分である。つぎに、図３に示すように、この混合粉末ｍを成形プレスＦにより所定形状に圧縮成形し、圧粉体１１を形成する。この圧粉体１１は、図５（ａ）に示すように、溶融点が１５３９．６℃であるＦｅ粉末中に、Ｐにより溶融点が下げられたＦｅ−Ｐ合金粉末が点在した状態となっている。
【００１４】
さらに、この圧粉体１１を、図４に示すように、焼結炉ＳによりＦｅ−５〜１５Ｐ合金の溶融点１０５０℃を超えＦｅの溶融点１５３９．６℃より低い焼結温度１１００〜１１５０℃で加熱し、Ｆｅ−５〜１５％Ｐ合金粉末部分を溶融させる液相焼結を行う。このような温度で処理することにより、圧粉体１１においては、図５（ｂ）に示すように、Ｆｅ−５〜１５％Ｐ合金粉末が溶融してＦｅ粉末の粒子間の空隙部１０ｂに浸透し、連結孔やオープンポア等の気孔を埋めて固化してＦｅ−Ｐ合金部１０ｃが形成される一方で、Ｆｅ粉末部分が拡散接合により形状を保ったまま焼結されてＦｅ部１０ａが形成される（図５（ｃ））。
【００１５】
このようにして得られた焼結品１０は、密度は焼結前後で大きく変わることはなく約７．３ｇ／ｃｍ ^３であって、有効多孔率約１．０％となる。なお、この焼結品１０は液相焼結により寸法精度が低下するため、焼結後にさらにサイジング等の再圧縮を行うことが好ましい。
【００１６】
なお、焼結時間は、圧粉体１１（焼結品１０）の焼結温度が１１００〜１１５０℃の状態で１０分間以上保持すると、全体を均一に焼結させることができる。たとえば圧粉体１１の大きさがφ２０である場合、２０〜３０分程度となる。焼結炉Ｓは、図では汎用性の高い連続式の焼結炉を用いているが、密閉炉を用いれば、処理量は少なくなるが焼結温度、焼結時間の設定を容易に変更することができる。
【００１７】
以上のように形成された本実施形態の焼結品１０と、従来の焼結品との比較を、有効多孔率と密度の関係を表す図６に示す。
図中、●で示す点Ａ〜点Ｆは、Ｆｅ粉末の加圧成形における圧力を異ならせることにより、密度を異ならせて成形したものであり、ぬれ性の悪いＮｉをろう材としたろう付けは可能である。この図からわかるように、成形時の圧力を大きくするほど、焼結品の密度を高めることができる。しかし、これらの焼結品に対してろう材にＣｕを用いたろう付けを行ったところ、ろう材が焼結品のオープンポアに吸収されて図７に示すような状態となり、接合させることはできなかった。なお、これ以上の高密度品を製造する圧力を与えるのは、通常の成形プレスの場合、現実的ではない。
【００１８】
点Ｇは、通常の成形プレスで加圧成形した点Ｆの焼結品に対し、焼結後に銅溶浸を行った焼結品の密度を示している。銅溶浸によって密度を高めることはできたものの、有効多孔率に大きな変化はなく、気孔（オープンポア）を完全に埋めることは難しい。さらに気孔を埋めているのがろう材と同じＣｕであるため、ろう材にＣｕを用いたろう付けを行うと、銅溶浸のＣｕが溶融することによりオープンポアが再度生じて、ろう材が焼結品に吸収されてしまい、図７に示すような状態となって接合させることはできなかった。
【００１９】
一方、点Ｈ（○）で示す本実施形態の焼結品１０は、密度は格別高くはないが、有効多孔率が低い。この焼結品１０は、銅溶浸とは異なり、Ｆｅ−Ｐ合金部１０ｃが気孔を塞いでいるため、ろう材にＣｕを用いたろう付けを行っても、ろう材が焼結品１０に吸収されず、図１に示すような状態となり確実な接合を行うことができた。さらに、この焼結品１０は、機械加工のように表面の目つぶしにより封孔するものとは異なりオープンポアが残っているため、このオープンポアに適量のろう材が吸収され、接合が強固なものとなっている。
【００２０】
このように、上述した製造方法により、部分的に生じた液相によりオープンポアが少なくなっているので、ろう材に用いたＣｕが過剰に吸収されることなく相手部材に接し、Ｃｕによるろう付けが可能な焼結品１０を得ることができる。
【００２１】
なお、前記実施形態において示した各構成部材の諸形状や組み合わせ等は一例であって、本発明の趣旨から逸脱しない範囲において設計要求等に基づき種々変更可能である。
【００２２】
【発明の効果】
以上説明したように、請求項１の発明に係る焼結品の製造方法によれば、焼結温度よりも溶融点が低い（１０５０℃）Ｆｅ−Ｐ合金粉末部分は溶融し、焼結温度よりも溶融点が高い（１５３９．６℃）Ｆｅ粉末部分は溶融しないので、液相が部分的に生じ、強度を保持しつつ、有効多孔率の低い焼結品を、高加圧成形や高温焼結によらず、低コストで製造することができる。このようにして得られた焼結品は、オープンポアが少ないため、ろう材として用いたＣｕを過剰に吸収することなく、Ｃｕのろう付けによる接合が可能となる。
したがって、高加圧成形や高温焼結を行わなくても、原料費のＣｕを用いるろう付けが可能な焼結品を、低コストで製造することができるので、ろう付けの原料費が低減され、焼結品をろう付けされた部品の製造コスト低減が実現される。
【００２３】
請求項２の発明に係る焼結品の製造方法によれば、Ｆｅ−Ｐ合金がＦｅの溶融点を下げるのにもっとも効果的な比率でＰを含有し、低い溶融点温度（１０５０℃）となるので、Ｆｅ粉末部分とＦｅ−Ｐ合金粉末部分の溶融点の差が大きく、確実に液相焼結を行うことができ、オープンポアが少なくろう付けに適した焼結品を製造することが可能となる。
【００２４】
請求項３の発明に係る焼結品の製造方法によれば、焼結品全体に対するＰの重量％を低く抑えているので、焼結品の形状を保って焼結処理を行うことができ、形状精度の優れた焼結品を製造することが可能となる。
【００２５】
請求項４の発明に係る焼結品の製造方法によれば、圧粉体全体を所定温度で一定時間保持することにより、オープンポアが少なくＣｕろう付けに適した焼結品を、確実に製造することができる。
【００２６】
請求項５の発明に係る焼結品によれば、通常の密度の焼結品でありながら、オープンポアが少なくて有効多孔率が低いので、ろう付けにおいてＣｕをろう材として用いてもＣｕが過剰に吸収されない、Ｃｕろう材によるろう付けが可能な焼結品が実現される。
したがって、焼結品において原料費の安いＣｕを用いたろう付けが可能となり、焼結品をろう付けした部品の製造コスト低減が実現される。
【図面の簡単な説明】
【図１】本発明による焼結品をろう付けして形成された部品を示す断面図である。
【図２】本発明の焼結品を製造する際の、混合粉末の製造工程を示す概念図である。
【図３】本発明の焼結品を製造する際の、圧粉体の製造工程を示す概念図である。
【図４】本発明の焼結品を製造する際の、焼結工程を示す概念図である。
【図５】本発明の焼結品の製造における混合粉末の焼結状態を示す図である。
【図６】焼結品の有効多孔率と密度との関係を表し、本発明の焼結品と従来の焼結品とを比較する図である。
【図７】従来の焼結品に対するＣｕをろう材としたろう付けによる各部材の状態を示す断面図である。
【符号の説明】
１０焼結品
１０ａＦｅ部
１０ｂ空隙部
１０ｃＦｅ−Ｐ合金部
１１圧粉体
２０パイプ
３０部品
ｍ混合粉末
Ｆ成形プレス
Ｍ混合機
Ｓ焼結炉
Ｗろう材[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a sintered product suitable for brazing and a sintered product.
[0002]
[Prior art]
Sintered products manufactured by sintering green compacts that are compression-molded powders can be made by combining multiple powder molded products or a combination of melted materials, resulting in complex shaped parts or partially different materials. It is possible to manufacture formed parts and parts integrally provided with a plurality of functions (gears, cams, levers, etc.). Brazing is employed as one of the joining techniques for forming such a sintered product.
[0003]
As a brazing material for joining members at the time of brazing, nickel brazing or the like is often used. However, it is required to reduce the cost by using less expensive copper as a brazing material. However, copper has a small surface tension and excellent wettability compared to nickel, and easily penetrates into the powder molded product from the open pores (pores communicating with the surface) of the joint. The penetration of the brazing material into the joining portion leads to an increase in joining strength . However, as shown in FIG. 7 , when the brazing material 100 is copper, most of it is absorbed into the powder molded product 101, and the joining portion has Since it does not remain, it is difficult to join the members.
[0004]
[Problems to be solved by the invention]
In order to enable brazing using a copper brazing material, it has been studied to leave the molten copper brazing material at the joint by techniques such as sealing processing of powder molded products and densification. . However, the sealing treatment by copper infiltration has a problem that the raw material cost increases because it is difficult to prevent the copper brazing material from being absorbed unless the open pores of the entire powder molded product are filled. Further, sealing treatment such as steam treatment or resin impregnation has a problem that production costs increase due to an increase in the number of steps.
[0005]
On the other hand, high-pressure molding for producing high-density green compacts with fewer pores requires a molding press with a large pressing capacity, and there is also a problem that the mold may be damaged, resulting in high manufacturing costs. . In addition, it is possible to make closed pores (pores that do not communicate with the surface) by liquid phase sintering by raising the sintering temperature, but not only the cost increases because the processing amount is small and equipment costs are increased, When the sintering is performed at a high temperature and the cooling time is prolonged, there is a problem that the crystal grains are increased and the strength of the sintered product is lowered.
[0006]
The present invention has been made in view of such problems, and a sintered product that can be reliably brazed using copper as a brazing material can be manufactured at low cost regardless of high pressure molding or high temperature sintering. The purpose is to get in.
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, a manufacturing method of a sintered product according to the invention of claim 1 is a method of compressing a mixed powder of Fe powder and Fe-P alloy powder to form a green compact, The powder is melted at a sintering temperature exceeding the melting point of the Fe-P alloy and lower than the melting point of Fe, without melting the Fe powder portion, and the void portion of the Fe powder portion is melted. and infiltrated sintering is characterized by obtaining a density 7.2~7.5 g / cm ^3, the effective porosity of 2% or less sinter for brazing.
According to the production method of the present invention, the Fe—P alloy powder portion having a melting point lower than the sintering temperature (1050 ° C.) is melted and the melting point is higher than the sintering temperature (1539.6 ° C.). Therefore, a sintered product having a low effective porosity can be produced at low cost regardless of high pressure molding or high temperature sintering, while a liquid phase is partially generated and strength is maintained. Since the sintered product thus obtained has few open pores, it is possible to join by brazing Cu without excessively absorbing Cu used as a brazing material.
[0008]
The method for producing a sintered product according to the invention of claim 2 is characterized in that, in the method for producing a sintered product of claim 1, the Fe—P alloy powder contains 5 to 15 wt% of P.
According to the present invention, since the Fe-P alloy contains P in the most effective ratio for lowering the melting point of Fe, it has a low melting point temperature (1050 ° C.). The difference in melting point of the -P alloy powder part is large, liquid phase sintering can be performed reliably, and it becomes possible to produce a sintered product with few open pores and suitable for brazing.
[0009]
The method for producing a sintered product according to the invention of claim 3 is the method for producing a sintered product of claim 1 or 2, wherein the mixed powder contains 0.2 to 0.8% by weight of P. It is said.
According to this invention, since the weight percentage of P with respect to the entire sintered product is kept low, the sintered product can be sintered while maintaining the shape of the sintered product, and a sintered product with excellent shape accuracy is manufactured. It becomes possible.
[0010]
The method for manufacturing a sintered product according to claim 4 is the method for manufacturing a sintered product according to claims 1 to 3, wherein the sintered product is held for 10 minutes or more at a sintering temperature of 1100 to 1150 ° C. It is characterized by that.
According to the present invention, by holding the whole green compact at a predetermined temperature for a certain period of time, a sintered product with few open pores and suitable for Cu brazing can be reliably manufactured.
[0011]
The sintered product according to the invention of claim 5 is a sintered product having a density of 7.2 to 7.5 g / cm ³ and an effective porosity of 2% or less formed from a mixed powder of Fe powder and Fe—P alloy powder. Fe parts formed by bonding the Fe powder particles to each other, and Fe-P melted and penetrated into the gaps between the particles of the Fe powder and then cooled and solidified in the gaps have a alloy portion, and characterized in that it is used for brazing.
According to the present invention, although it is a sintered product having a normal density, Cu is not absorbed excessively even when Cu is used as a brazing material in brazing because Cu has a low open pore and a low effective porosity. A sintered product that can be brazed by is realized.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view showing a mechanical component 30 formed by joining a sintered product 10 according to the present invention and a pipe 20 made of a molten material by brazing. The sintered product 10 is a ring-shaped member made of an Fe—P alloy and having a density of about 7.3 g / cm ³ and an effective porosity of about 1.0%. The ring-shaped brazing material W made of is heated in a state of being fitted to the pipe 20, whereby the pipe 20 and the sintered product 10 are joined.
[0013]
Here, a method for manufacturing the sintered product 10 will be described.
First, as shown in FIG. 2, Fe powder, Fe-5-15% P alloy powder and a lubricant are mixed by a mixer M to produce an iron-based mixed powder m containing 0.6% by mass of P. P is a component for lowering the melting point of Fe. Next, as shown in FIG. 3, this mixed powder m is compression-molded into a predetermined shape by a molding press F to form a green compact 11. As shown in FIG. 5 (a), this green compact 11 is in a state where Fe—P alloy powders whose melting point has been lowered by P are scattered in Fe powder having a melting point of 1539.6 ° C. It has become.
[0014]
Further, as shown in FIG. 4, the green compact 11 is sintered in a sintering furnace S at a sintering temperature 1100 to 1150 which exceeds the melting point 1050 ° C. of the Fe-5-15P alloy and is lower than the melting point 1539.6 ° C. of Fe. Liquid phase sintering is performed by heating at 5 ° C. to melt the Fe-5 to 15% P alloy powder portion. By processing at such a temperature, in the green compact 11, as shown in FIG. 5 (b), the Fe-5-15% P alloy powder is melted and formed in the void 10 b between the Fe powder particles. The Fe-P alloy part 10c is formed by infiltrating and filling the pores such as connection holes and open pores to solidify, while the Fe powder part is sintered while maintaining its shape by diffusion bonding, and the Fe part 10a is formed. It is formed (FIG. 5C).
[0015]
The sintered product 10 thus obtained has a density of about 7.3 g / cm ³ without significantly changing before and after sintering, and has an effective porosity of about 1.0%. In addition, since the dimensional accuracy of the sintered product 10 is reduced by liquid phase sintering, it is preferable to perform recompression such as sizing after sintering.
[0016]
In addition, as for sintering time, if the sintering temperature of the green compact 11 (sintered product 10) is kept at 1100 to 1150 ° C. for 10 minutes or more, the whole can be sintered uniformly. For example, when the size of the green compact 11 is φ20, it is about 20 to 30 minutes. In the figure, the sintering furnace S uses a highly versatile continuous sintering furnace, but if a closed furnace is used, the processing amount is reduced, but the setting of the sintering temperature and the sintering time can be easily changed. be able to.
[0017]
A comparison between the sintered product 10 of the present embodiment formed as described above and a conventional sintered product is shown in FIG. 6 showing the relationship between effective porosity and density.
In the figure, points A to F indicated by ● are formed by varying the pressure in the pressure forming of Fe powder to form different densities, and brazing using Ni having poor wettability as a brazing material. Is possible. As can be seen from this figure, the density of the sintered product can be increased as the pressure during molding is increased. However, when brazing using Cu as a brazing material to these sintered products, the brazing material is absorbed by the open pores of the sintered product and becomes a state as shown in FIG. 7, and can be joined. There wasn't. In addition, it is not realistic to give the pressure which manufactures a high-density product beyond this in the case of a normal molding press.
[0018]
Point G indicates the density of a sintered product obtained by performing copper infiltration after sintering with respect to a sintered product of point F that has been pressure-molded by a normal molding press. Although the density could be increased by copper infiltration, there was no significant change in the effective porosity, and it was difficult to completely fill the pores (open pores). Further, since the same Cu as the brazing material fills the pores, when the brazing using Cu is performed on the brazing material, the copper infiltrated Cu melts to cause open pores again, and the brazing material is baked. It was absorbed by the product and could not be joined in the state shown in FIG.
[0019]
On the other hand, the sintered product 10 of the present embodiment indicated by the point H (◯) has a low effective porosity although the density is not particularly high. Unlike the copper infiltration, the sintered product 10 has pores closed by the Fe-P alloy portion 10c. Therefore, even when brazing using Cu as the brazing material, the brazing material is absorbed by the sintered product 10. Instead, the state shown in FIG. 1 was obtained, and reliable bonding could be performed. Furthermore, this sintered product 10 has open pores different from those sealed by crushing the surface as in machining, so that an appropriate amount of brazing material is absorbed into the open pores and the bonding is strong. It has become.
[0020]
Thus, since the open pores are reduced due to the partially generated liquid phase by the above-described manufacturing method, Cu used for the brazing material is in contact with the mating member without being excessively absorbed, and brazing with Cu Thus, a sintered product 10 that can be obtained can be obtained.
[0021]
The shapes, combinations, and the like of the constituent members shown in the embodiment are merely examples, and various modifications can be made based on design requirements and the like without departing from the spirit of the present invention.
[0022]
【The invention's effect】
As described above, according to the method for manufacturing a sintered product according to the first aspect of the present invention, the Fe—P alloy powder portion having a melting point lower than the sintering temperature (1050 ° C.) is melted and is lower than the sintering temperature. However, since the Fe powder portion having a high melting point (1539.6 ° C.) does not melt, a liquid phase is partially generated, and a sintered product having a low effective porosity while maintaining strength is formed by high pressure molding or high temperature sintering. Regardless of the result, it can be manufactured at low cost. Since the sintered product thus obtained has few open pores, it is possible to join by brazing Cu without excessively absorbing Cu used as a brazing material.
Therefore, a sintered product that can be brazed using Cu, which is the raw material cost, can be manufactured at low cost without performing high pressure molding or high temperature sintering, so that the raw material cost for brazing is reduced. The manufacturing cost of the parts brazed with the sintered product can be reduced.
[0023]
According to the method for manufacturing a sintered product according to the invention of claim 2, the Fe—P alloy contains P in a ratio most effective for lowering the melting point of Fe, and has a low melting point temperature (1050 ° C.). As a result, the difference in melting point between the Fe powder part and the Fe-P alloy powder part is large, liquid phase sintering can be performed reliably, and a sintered product suitable for brazing can be produced with less open pores. It becomes possible.
[0024]
According to the method for manufacturing a sintered product according to the invention of claim 3, since the weight percentage of P with respect to the entire sintered product is kept low, the sintering treatment can be performed while maintaining the shape of the sintered product, It becomes possible to manufacture a sintered product with excellent shape accuracy.
[0025]
According to the method for manufacturing a sintered product according to the invention of claim 4, a sintered product that has few open pores and is suitable for Cu brazing is reliably manufactured by holding the whole green compact at a predetermined temperature for a certain time. can do.
[0026]
According to the sintered product of the invention of claim 5, although it is a sintered product having a normal density, there are few open pores and the effective porosity is low. A sintered product that is not excessively absorbed and can be brazed with a Cu brazing material is realized.
Therefore, it is possible to braze using Cu, which has a low raw material cost, in the sintered product, thereby realizing a reduction in the manufacturing cost of the parts brazed with the sintered product.
[Brief description of the drawings]
FIG. 1 is a sectional view showing a part formed by brazing a sintered product according to the present invention.
FIG. 2 is a conceptual diagram showing a mixed powder manufacturing process when a sintered product of the present invention is manufactured.
FIG. 3 is a conceptual diagram showing a green compact manufacturing process when the sintered product of the present invention is manufactured.
FIG. 4 is a conceptual diagram showing a sintering process when manufacturing a sintered product of the present invention.
FIG. 5 is a diagram showing a sintered state of mixed powder in the production of a sintered product of the present invention.
FIG. 6 is a diagram showing the relationship between the effective porosity and density of a sintered product, and comparing the sintered product of the present invention with a conventional sintered product.
FIG. 7 is a cross-sectional view showing the state of each member by brazing using Cu as a brazing material for a conventional sintered product.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Sintered product 10a Fe part 10b Cavity part 10c Fe-P alloy part 11 Green compact 20 Pipe 30 Parts m Mixed powder F Molding press M Mixer S Sintering furnace W Brazing material

Claims

A mixed powder of Fe powder and Fe-P alloy powder is compression molded to form a green compact,
The green compact is melted at a sintering temperature that is higher than the melting point of the Fe-P alloy and lower than the melting point of Fe, without melting the Fe powder portion. Penetration into the gap and sintering
A method for producing a sintered product, characterized by obtaining a sintered product for brazing having a density of 7.2 to 7.5 g / cm ³ and an effective porosity of 2% or less.

The said Fe-P alloy powder contains 5 to 15 weight% of P, The manufacturing method of the sintered article of Claim 1 characterized by the above-mentioned.

The method for producing a sintered product according to claim 1 or 2, wherein the mixed powder contains 0.2 to 0.8 wt% of P.

The method for producing a sintered product according to any one of claims 1 to 3, wherein, in the sintering, the sintered product is held at a sintering temperature of 1100 to 1150 ° C for 10 minutes or more. .

A sintered product having a density of 7.2 to 7.5 g / cm ³ and an effective porosity of 2% or less formed from a mixed powder of Fe powder and Fe—P alloy powder,
Fe portion formed by bonding the particles of the Fe powder, and an Fe-P alloy portion that has been melted and penetrated into the voids between the particles of the Fe powder and then cooled and solidified in the voids. And sintered product characterized by being used for brazing .