JP2007064165A - Combination of valve and valve seat for internal combustion engine - Google Patents

Combination of valve and valve seat for internal combustion engine Download PDF

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JP2007064165A
JP2007064165A JP2005254593A JP2005254593A JP2007064165A JP 2007064165 A JP2007064165 A JP 2007064165A JP 2005254593 A JP2005254593 A JP 2005254593A JP 2005254593 A JP2005254593 A JP 2005254593A JP 2007064165 A JP2007064165 A JP 2007064165A
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valve
valve seat
alloy
combination
intermetallic compound
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JP4335189B2 (en
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Kenichi Sato
佐藤  賢一
Teruo Takahashi
輝夫 高橋
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Nippon Piston Ring Co Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a durable combination of a titanium alloy valve and a valve seat. <P>SOLUTION: The titanium alloy valve having atomized Co base metal chemical compound dispersion particle having 20-70 μm average particle diameter and 600-1000 Hv0.1 hardness dispersed in matrix phase by 10-40 area% as hard particle and the valve seat formed out of iron base sintered alloy material containing C of 0.5-1.5% in matrix phase and containing one or more kinds of components selected from Ni, Cr, Mo, Co, Cu, V, W by total 3.0-10.0% are combined. Consequently, excellent wear resistance of the valve seat is secured, aggressiveness is reduced, and wear resistance of the valve seat is improved. Atomized Co base metal chemical compound particle is preferably Si-Cr-Mo base Co base metal chemical compound dispersion particle or Si-Cr-Mo-Ni base Co base metal chemical compound particle. Ti-6Al-4V alloy of titanium alloy used for the valve is preferably Ti-6Al-2Sn-4Zr-2Mo-0.2Si alloy or Ti-2.7Sn-4Zr-0.4Mo-0.5Si alloy. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は、内燃機関用のバルブとバルブシートとの組合せに係り、とくにチタン合金製バルブが組み込まれる内燃機関用として、バルブシートの相手攻撃性の低減に関する。   The present invention relates to a combination of a valve and a valve seat for an internal combustion engine, and more particularly, to a reduction in counter attack of a valve seat for an internal combustion engine in which a titanium alloy valve is incorporated.

バルブシートは、内燃機関(エンジン)のシリンダヘッドに圧入あるいは接合されて、燃焼ガスのシールとバルブを冷却する役割を担っている。バルブシートは、バルブによる叩かれ、すべりによる摩耗や、燃焼ガスによる加熱、燃焼生成物による腐食等に晒されるため、従来から、耐熱性、耐摩耗性に優れることが要求されている。近年、このような耐熱性、耐摩耗性に優れることが要求されるバルブシートに、焼結合金が適用されている。   The valve seat is press-fitted or joined to a cylinder head of an internal combustion engine (engine) and plays a role of cooling a combustion gas seal and a valve. The valve seat is hit by a valve, and is exposed to wear due to sliding, heating by combustion gas, corrosion by combustion products, and the like, so that it has been conventionally required to have excellent heat resistance and wear resistance. In recent years, sintered alloys have been applied to such valve seats that are required to have excellent heat resistance and wear resistance.

一方、エンジン動弁系部品のなかでもバルブは、軽量化することがエンジンの性能向上に直接結びつくことから、とくに競技用の小型で軽量しかも高出力の高性能エンジンでは、従来から鋼製のバルブに代えて、チタン合金製バルブの使用が考えられてきた。そして、このような競技用高性能エンジンでは、バルブシートとして、Cu−Be系材料製が使用されていた。このようなバルブとバルブシートの組合せにより、軽量化が達成され、出力の向上、燃費の向上等が図られることになる。Cu−Be系材料のバルブシートはチタン合金製バルブへの攻撃性は低いが、しかし、Cu−Be系材料が鉄系材料に比べて塑性変形しやすいことおよび摩耗が生じやすいことに起因して、Cu−Be系材料製バルブシートの耐摩耗性が非常に低く、そのため、チタン合金製バルブとCu−Be系材料製バルブシートとの組合せは、耐久性に乏しく、一般市販車のエンジンに適用することは実用上問題があった。   On the other hand, among the valve operating parts of the engine, the weight reduction of the valve directly leads to the improvement of the engine performance. Therefore, in the high performance engine of small size, light weight and high output for competition, the steel valve has been conventionally used. Instead, the use of titanium alloy valves has been considered. And in such a high-performance engine for competition, the product made from Cu-Be system material was used as a valve seat. Such a combination of a valve and a valve seat achieves a reduction in weight, thereby improving output and fuel consumption. Cu-Be-based valve seats are less aggressive to titanium alloy valves, but Cu-Be-based materials are more susceptible to plastic deformation and wear than iron-based materials. The wear resistance of Cu-Be based valve seats is very low, so the combination of titanium alloy valves and Cu-Be based valve seats is not very durable and can be applied to general commercial vehicle engines. There was a problem in practical use.

最近では、地球環境の保全という観点から、燃費改善、高出力化、さらには静粛性の向上などの要望に対処するため、一般市販車へのチタン合金製バルブの採用が拡大しつつある。そのため、チタン合金製バルブに対応したバルブシートの開発が強く要求されるようになってきた。
例えば、特許文献1には、バルブシートを、C:0.4〜1.5%と、Cu、Co、Niよりなる群から選択された少なくとも1種の元素:0.5〜10.0%含有し、ビッカース硬さHVが170〜350である鉄合金製とし、バルブを、CoもしくはNi:7〜13%、またはCoとNiとの合計7〜13%、Al:3〜7%を含有し、ビッカース硬さHVが350〜550であるチタン合金とする、バルブシートとバルブの組合せが開示されている。特許文献1に記載された技術では、バルブシートには、耐摩耗性向上のために、ステライト合金、イートナイト系合金、Mo−Fe、各種セラミック等の800HV以上の硬さを有する硬質粒子を含有してもよいとしている。さらに、特許文献1に記載された技術では、バルブシートには、バルブシートを形成する鉄合金に自己潤滑性を付与し耐摩耗性を向上させるとともにチタン合金製バルブへの相手攻撃性低減のために、鉛(Pb)を含有してもよいとしている。しかし、鉛は環境負荷物質であり、環境への影響が懸念され、一般の市販車への適用には問題を残していた。
Recently, from the viewpoint of protecting the global environment, the adoption of titanium alloy valves in general commercial vehicles is expanding to meet demands for improving fuel economy, increasing output, and improving quietness. Therefore, development of a valve seat corresponding to a titanium alloy valve has been strongly demanded.
For example, Patent Document 1 contains a valve seat of C: 0.4 to 1.5% and at least one element selected from the group consisting of Cu, Co, and Ni: 0.5 to 10.0%, and a Vickers hardness HV. It is made of an iron alloy that is 170 to 350, and the valve contains Co or Ni: 7 to 13%, or a total of 7 to 13% of Co and Ni, Al: 3 to 7%, and a Vickers hardness HV of 350 A combination of valve seat and valve is disclosed which is a titanium alloy of ~ 550. In the technique described in Patent Document 1, the valve seat contains hard particles having a hardness of 800 HV or more, such as stellite alloy, eatnite-based alloy, Mo-Fe, and various ceramics, in order to improve wear resistance. You can do it. Furthermore, in the technique described in Patent Document 1, the valve seat is provided with a self-lubricating property to the iron alloy forming the valve seat to improve wear resistance, and at the same time, to reduce the opponent attack on the titanium alloy valve. In addition, it may contain lead (Pb). However, lead is an environmentally hazardous substance, and there are concerns about its impact on the environment, leaving problems for general commercial vehicles.

また、特許文献2には、600HV以上の硬さを有すると共に、酸素あるいは窒素または酸素および窒素が固溶したチタン合金硬化層を有するバルブと、C:0.4〜1.5%、ならびにCu、Co、Niよりなる群から選択される少なくとも1種の元素0.5〜10.0%を含有し、残部が実質的にFeからなるHV:170〜350の硬さを有するバルブシートとからなる、バルブおよびバルブシート組立て体が提案されている。しかし、特許文献2に記載された技術では、バルブの摩耗は抑制されるが、バルブシートの耐摩耗性向上は不十分であるという問題があった。   Patent Document 2 discloses a valve having a hardness of 600 HV or more and a hardened titanium alloy layer in which oxygen or nitrogen or oxygen and nitrogen is dissolved, C: 0.4 to 1.5%, and Cu, Co, Ni A valve and a valve seat assembly comprising a valve seat having a hardness of HV: 170 to 350 containing at least one element selected from the group consisting of 0.5 to 10.0% and the balance being substantially Fe Has been proposed. However, although the technique described in Patent Document 2 suppresses the wear of the valve, there is a problem that the wear resistance of the valve seat is insufficiently improved.

また、特許文献3には、フェース部にTiC粒子が3〜50体積%分散したチタン基合金の肉盛を施した排気用チタンバルブと、Ni、Si、Coの適正量を含みさらにW、Mo、Nb、Vの1種または2種以上を適正量含有し、W、Mo、Nb、Vのシリサイドを含む硬質相がマトリックス中に分散した組織の耐摩耗性銅合金よりなるバルブシートと、の組合せが提案されている。しかし、特許文献3に記載された技術では、バルブフェース部の摩耗は抑制されるが、バルブシートが銅合金であり、高温強度が低く、耐摩耗性が不十分であるという問題が残されている。
特許第3361113号公報 特開平6−167206号公報 特開平6−10081号公報
Further, Patent Document 3 includes an exhaust titanium valve with a titanium base alloy in which 3 to 50% by volume of TiC particles are dispersed in the face portion, and appropriate amounts of Ni, Si, and Co, and further includes W, Mo. A valve seat made of a wear-resistant copper alloy having a structure in which a hard phase containing W, Mo, Nb, V silicide is dispersed in a matrix, containing an appropriate amount of one or more of Nb, V, A combination is proposed. However, in the technique described in Patent Document 3, wear of the valve face portion is suppressed, but the problem remains that the valve seat is a copper alloy, the high-temperature strength is low, and the wear resistance is insufficient. Yes.
Japanese Patent No. 3361113 JP-A-6-167206 Japanese Patent Laid-Open No. 6-1000081

チタン合金製バルブでは、通常、フェース部に酸化処理により酸素拡散硬化層を形成し、これによりバルブの耐摩耗性を維持している。このようなチタン合金製バルブが組み込まれる高性能エンジンに、上記したような、ステライト合金、イートナイト系合金、Mo−Fe、各種セラミック等の硬質粒子を含有するバルブシートを適用すると、過大摩耗が発生しやすくなり、このため、バルブ機能が維持できなくなり、エンジン性能の低下を招く恐れがあるという問題があった。   In a titanium alloy valve, an oxygen diffusion hardened layer is usually formed on the face portion by oxidation treatment, thereby maintaining the wear resistance of the valve. When a valve seat containing hard particles such as stellite alloy, eatnite alloy, Mo-Fe, and various ceramics as described above is applied to a high-performance engine in which such a titanium alloy valve is incorporated, excessive wear is caused. As a result, the valve function cannot be maintained and the engine performance may be degraded.

本発明は、かかる従来技術の問題を有利に解決し、チタン合金製バルブが組み込まれる高性能エンジン用として、耐久性に優れた、内燃機関用のチタン合金製バルブとバルブシートの組合せを提案することを目的とする。本発明は、チタン合金製バルブに、チタン合金製バルブへの攻撃性が低く、かつ高耐摩耗性を有するバルブシートとを組合せて、バルブとバルブシートの耐久性向上を図ることを目的とする。   The present invention advantageously solves the problems of the prior art and proposes a combination of a titanium alloy valve and a valve seat for an internal combustion engine, which is excellent in durability, for a high performance engine in which a titanium alloy valve is incorporated. For the purpose. An object of the present invention is to improve the durability of a valve and a valve seat by combining a titanium alloy valve with a valve seat having a low aggressiveness to a titanium alloy valve and having high wear resistance. .

本発明者らは、上記した課題を達成するために、バルブシートの、チタン合金製バルブへの攻撃性に影響する要因について鋭意考究した。その結果、バルブシートの基地相中に分散しバルブシートの耐摩耗性を向上させる硬質粒子が、相手材であるチタン合金製バルブの酸素拡散硬化層を攻撃、破壊し、チタン合金母材と直接摺動し、過大摩耗を発生させることを突き止めた。そして、硬質粒子を、所定範囲の硬さ、粒径を有するアトマイズ製のCo基金属間化合物粒子とし、基地相中に適正量含有させるとともに、基地相組成を適正組成に調整したバルブシートとすることにより、バルブシートの耐摩耗性が向上するとともに、チタン合金製バルブの耐摩耗性が向上することを知見した。バルブの耐摩耗性が向上する詳しい機構については、現在のところ明確となっているわけではないが、発明者らは、つぎのように考えている。   In order to achieve the above-mentioned problems, the present inventors diligently studied factors that affect the aggressiveness of the valve seat to the titanium alloy valve. As a result, hard particles that are dispersed in the base phase of the valve seat and improve the wear resistance of the valve seat attack and destroy the oxygen diffusion hardened layer of the titanium alloy valve that is the counterpart material, and directly with the titanium alloy base material. Sliding and found to cause excessive wear. The hard particles are atomized Co-based intermetallic compound particles having a predetermined range of hardness and particle size, and a proper amount is contained in the matrix phase, and the matrix composition is adjusted to an appropriate composition. Thus, it was found that the wear resistance of the valve seat is improved and the wear resistance of the titanium alloy valve is improved. Although the detailed mechanism for improving the wear resistance of the valve is not clear at present, the inventors consider as follows.

アトマイズ製のCo基金属間化合物粒子は、粒子自体が球状を呈するうえ、鉄基焼結合金製のバルブシートの基地相中に分散させると、基地相中に比較的高硬度の高合金相が多数形成されるため、硬質粒子と基地相との硬さ差が少なくなり、バルブとの摺動面で硬質粒子が浮き出ることがなく摺動面が比較的平滑化して、チタン合金製バルブの酸素拡散硬化層への攻撃、破壊を防止でき、バルブの耐摩耗性が向上するものと考えられる。   The atomized Co-based intermetallic compound particles have a spherical shape, and when dispersed in the matrix phase of a valve seat made of an iron-based sintered alloy, a relatively high hardness high alloy phase is present in the matrix phase. Since many are formed, the hardness difference between the hard particles and the matrix phase is reduced, the hard particles do not float on the sliding surface with the valve, the sliding surface is relatively smooth, and the oxygen of the titanium alloy valve It is considered that attack and destruction of the diffusion hardened layer can be prevented, and the wear resistance of the valve is improved.

本発明は、上記した知見に基づき、さらに検討を加えて完成されたものである。すなわち、本発明の要旨は次のとおりである。
(1)内燃機関におけるバルブとバルブシートの組合せであって、前記バルブが、チタン合金製バルブであり、前記バルブシートが、基地相中に硬質粒子として、20〜70μmの平均粒径と600〜1000HV0.1の硬さを有するアトマイズ製Co基金属間化合物粒子を質量%で10.0〜40.0%分散させ、前記基地相が、質量%で、C:0.5〜1.5%を含み、さらにNi、Cr、Mo、Co、Cu、V、Wのうちから選ばれた1種または2種以上を合計で3.0〜10.0%含有し、残部Feおよび不可避的不純物からなる組成を有し、かつ前記Co基金属間化合物粒子の周囲に該Co基金属化合物粒子の合金成分の拡散により形成された高合金相を有する鉄基焼結合金材からなることを特徴とする内燃機関用バルブとバルブシートの組合せ。
The present invention has been completed based on the above findings and further studies. That is, the gist of the present invention is as follows.
(1) A combination of a valve and a valve seat in an internal combustion engine, wherein the valve is a titanium alloy valve, and the valve seat has an average particle size of 20 to 70 μm and 600 to 600 as hard particles in the base phase. Atomized Co-based intermetallic compound particles having a hardness of 1000 HV0.1 are dispersed in an amount of 10.0 to 40.0% by mass%, and the matrix phase contains C: 0.5 to 1.5% by mass%, and Ni, Cr, One or two or more selected from Mo, Co, Cu, V, and W are contained in a total amount of 3.0 to 10.0%, and the composition is composed of the remaining Fe and inevitable impurities, and between the Co-based metals A combination of a valve for an internal combustion engine and a valve seat, comprising an iron-based sintered alloy material having a high alloy phase formed by diffusion of alloy components of the Co-based metal compound particles around the compound particles.

(2)(1)において、前記アトマイズ製Co基金属間化合物粒子が、質量%で、Si:0.5〜4.0%、Cr:5.0〜20.0%、Mo:20.0〜40.0%を含み残部Coおよび不可避的不純物からなる組成を有するアトマイズ製Si−Cr−Mo系Co基金属間化合物粒子、または、Si:0.5〜4.0%、Cr:15.0〜25.0%、Mo:15.0〜35.0%、Ni:5.0〜20.0%を含み、残部Coおよび不可避的不純物からなる組成を有するアトマイズ製Si−Cr−Mo−Ni系Co基金属間化合物粒子であることを特徴とする内燃機関用バルブとバルブシートの組合せ。   (2) In (1), the atomized Co-based intermetallic compound particles contain, by mass%, Si: 0.5 to 4.0%, Cr: 5.0 to 20.0%, Mo: 20.0 to 40.0%, and the remainder Co and unavoidable Atomized Si-Cr-Mo Co-based intermetallic compound particles having a composition comprising impurities, or Si: 0.5 to 4.0%, Cr: 15.0 to 25.0%, Mo: 15.0 to 35.0%, Ni: 5.0 to 20.0% A combination of a valve for an internal combustion engine and a valve seat, characterized by being atomized Si-Cr-Mo-Ni Co-based intermetallic compound particles having a composition composed of the remainder Co and inevitable impurities.

(3)(1)または(2)において、前記バルブシートが、前記基地相中に前記硬質粒子に加えてさらに、固体潤滑剤粒子を質量%で0.2〜3.0%分散させることを特徴とする内燃機関用バルブとバルブシートの組合せ。
(4)(1)ないし(3)のいずれかにおいて、前記チタン合金製バルブが、Ti−6Al−4V合金製バルブ、Ti−6Al−2Sn−4Zr−2Mo−0.2Si合金製バルブまたはTi−2.7Sn−4Zr−0.4Mo−0.5Si合金製バルブとすることを特徴とする内燃機関用バルブとバルブシートの組合せ。
(3) The internal combustion engine according to (1) or (2), wherein the valve seat further disperses 0.2 to 3.0% by mass of solid lubricant particles in addition to the hard particles in the matrix phase. Combination of engine valve and valve seat.
(4) In any one of (1) to (3), the titanium alloy valve is a Ti-6Al-4V alloy valve, a Ti-6Al-2Sn-4Zr-2Mo-0.2Si alloy valve, or Ti-2.7. A combination of a valve for an internal combustion engine and a valve seat, characterized by being a valve made of Sn-4Zr-0.4Mo-0.5Si alloy.

(5)(1)ないし(4)のいずれかにおいて、前記チタン合金製バルブが、硬さ:400HV0.01以上の酸素拡散硬化層を有することを特徴とする内燃機関用バルブとバルブシートの組合せ。
(6)内燃機関においてチタン合金製バルブと組合せて使用されるバルブシートであって、前記バルブシートが、基地相中に硬質粒子を分散させた鉄基焼結合金材からなり、前記硬質粒子を20〜70μmの平均粒径と600〜1000HV0.1の硬さを有するアトマイズ製Co基金属間化合物粒子とし質量%で10.0〜40.0%分散させ、前記基地相が、質量%で、C:0.5〜1.5%を含み、さらにNi、Cr、Mo、Co、Cu、V、Wのうちから選ばれた1種または2種以上を合計で3.0〜10.0%含有し、残部Feおよび不可避的不純物からなる組成を有し、かつ前記Co基金属間化合物粒子の周囲に該Co基金属間化合物粒子の合金成分の拡散により形成された高合金相を有する鉄基焼結合金材からなることを特徴とするチタン合金製バルブ用バルブシート。
(5) The combination of a valve for an internal combustion engine and a valve seat, wherein the titanium alloy valve has an oxygen diffusion hardened layer having a hardness of 400HV0.01 or more in any one of (1) to (4) .
(6) A valve seat used in combination with a titanium alloy valve in an internal combustion engine, wherein the valve seat is made of an iron-based sintered alloy material in which hard particles are dispersed in a matrix phase. Atomized Co-based intermetallic compound particles having an average particle diameter of 20 to 70 μm and a hardness of 600 to 1000 HV0.1 are dispersed in an amount of 10.0 to 40.0% by mass, and the matrix phase is in mass%, and C: 0.5 to A composition containing 1.5% and further containing one or more selected from Ni, Cr, Mo, Co, Cu, V, and W in a total of 3.0 to 10.0%, the balance being Fe and inevitable impurities And an iron-based sintered alloy material having a high alloy phase formed by diffusion of alloy components of the Co-based intermetallic compound particles around the Co-based intermetallic compound particles Valve seat for alloy valves.

(7)(6)において、前記アトマイズ製Co基金属間化合物粒子が、質量%で、Si:0.5〜4.0%、Cr:5.0〜20.0%、Mo:20.0〜40.0%を含み残部Coおよび不可避的不純物からなる組成を有するアトマイズ製Co基金属間化合物粒子、または、質量%で、Si:0.5〜4.0%、Cr:15.0〜35.0%、Mo:15.0〜35.0%、Ni:5.0〜20.0%を含み、残部Coおよび不可避的不純物からなる組成を有するアトマイズ製Co基金属間化合物粒子であることを特徴とするバルブシート。   (7) In (6), the atomized Co-based intermetallic compound particles contain, by mass%, Si: 0.5 to 4.0%, Cr: 5.0 to 20.0%, Mo: 20.0 to 40.0%, and the remainder Co and unavoidable Atomized Co-based intermetallic compound particles having a composition comprising impurities, or in mass%, Si: 0.5 to 4.0%, Cr: 15.0 to 35.0%, Mo: 15.0 to 35.0%, Ni: 5.0 to 20.0% A valve seat characterized by being atomized Co-based intermetallic compound particles having a composition comprising the remainder Co and inevitable impurities.

(8)(6)または(7)において、前記基地相中に前記硬質粒子に加えてさらに、固体潤滑剤粒子を質量%で0.2〜3.0%分散させたことを特徴とするバルブシート。   (8) The valve seat according to (6) or (7), wherein solid lubricant particles are further dispersed in an amount of 0.2 to 3.0% by mass in the matrix phase in addition to the hard particles.

本発明によれば、バルブシートを、耐摩耗性に優れるとともに、相手材への攻撃性を抑制したバルブシートとすることができ、チタン合金製バルブに組合せることにより、チタン合金製バルブの耐摩耗性低下を抑制して、バルブ構造の耐久性向上に寄与し、さらには内燃機関の高性能化に寄与するという、産業上格段の効果を奏する。   According to the present invention, the valve seat can be made into a valve seat that has excellent wear resistance and suppresses the aggressiveness to the mating material. By combining with the titanium alloy valve, the valve seat can be made resistant to titanium alloy. There is a remarkable industrial effect of suppressing wear deterioration, contributing to improving the durability of the valve structure, and further contributing to improving the performance of the internal combustion engine.

本発明の内燃機関用バルブとバルブシートの組合せでは、バルブをチタン合金製バルブとし、バルブシートを、基地相中に硬質粒子として、アトマイズ製Co基金属間化合物粒子を分散させた鉄基焼結合金材からなるバルブシートとする。
まず、本発明で使用するバルブシート用の鉄基焼結合金材について説明する。
本発明で使用するバルブシート用鉄基焼結合金材は、基地相中に硬質粒子を分散させたものであり、硬質粒子は、バルブシートの耐摩耗性、バルブへの相手攻撃性に影響を与える。このため、本発明では、バルブシートの基地相中に分散させる硬質粒子は、アトマイズ製Co基金属間化合物粒子とした。そして、本発明では、Co基金属間化合物粒子の分散量を、質量%で10.0〜40.0%の範囲に限定した。分散量が、10.0%未満では、相手攻撃性は低いが、バルブシートの耐摩耗性が所望のレベルを維持できなくなる。一方、40.0%を超える分散量では、相手攻撃性が強くなりすぎるとともに、効果が飽和し、分散量に見合う効果が期待できなくなり、経済的に不利となる。このようなことから、Co基金属間化合物粒子の分散量を質量%で10.0〜40.0%の範囲に限定した。
In the combination of a valve for an internal combustion engine and a valve seat according to the present invention, the valve is a titanium alloy valve, the valve seat is a hard particle in the base phase, and an iron-based sintered bond in which atomized Co-based intermetallic compound particles are dispersed. The valve seat is made of gold.
First, the iron-based sintered alloy material for valve seats used in the present invention will be described.
The iron-based sintered alloy material for valve seats used in the present invention is one in which hard particles are dispersed in the matrix phase, and the hard particles have an influence on the wear resistance of the valve seat and the attack resistance against the valve. give. For this reason, in the present invention, the hard particles dispersed in the base phase of the valve seat are atomized Co-based intermetallic compound particles. In the present invention, the amount of Co-based intermetallic compound particles dispersed is limited to a range of 10.0 to 40.0% by mass%. If the amount of dispersion is less than 10.0%, the attack of the opponent is low, but the wear resistance of the valve seat cannot be maintained at a desired level. On the other hand, when the amount of dispersion exceeds 40.0%, the opponent's aggression becomes too strong, the effect is saturated, and an effect commensurate with the amount of dispersion cannot be expected, resulting in an economical disadvantage. For this reason, the dispersion amount of the Co-based intermetallic compound particles is limited to a range of 10.0 to 40.0% by mass.

また、本発明で使用するCo基金属間化合物粒子は、比較的軟らかいCo基地中に硬さの高い金属間化合物が分散した粒子であり、鉄基焼結合金材の基地相への焼結拡散性が良好であり、300〜600HV0.1の硬さを有する高合金相の多量形成を容易にでき、基地相硬さを高めることが容易となる。本発明では、Co基金属間化合物粒子は、ほぼ球状を呈する、アトマイズ製粒子を用いるものとする。アトマイズ製粒子は、通常のアトマイズ法で製造された粒子であり、使用するアトマイズ法をとくに限定する必要はないが、粒子形状の観点から、水アトマイズ法を利用して製造された粒子とすることが好ましい。   Further, the Co-based intermetallic compound particles used in the present invention are particles in which a high-hardness intermetallic compound is dispersed in a relatively soft Co matrix, and sintering diffusion to the matrix phase of the iron-based sintered alloy material Therefore, it is possible to easily form a large amount of a high alloy phase having a hardness of 300 to 600 HV0.1, and to easily increase the base phase hardness. In the present invention, the Co-based intermetallic compound particles are atomized particles that are substantially spherical. Atomized particles are particles produced by the normal atomization method, and it is not necessary to specifically limit the atomization method to be used. However, from the viewpoint of particle shape, the particles should be produced using the water atomization method. Is preferred.

ほぼ球状のアトマイズ製Co基金属間化合物粒子を基地相中に分散させることにより、バルブへの相手攻撃性が抑制され、バルブの耐摩耗性の低下を抑制することができる。これは、上記したように、アトマイズ製のCo基金属間化合物粒子自体が球状を呈するうえ、基地相中に300〜600HV0.1の硬さを有する高合金相を比較的多量に形成できるため、硬質粒子と基地相との間で段階的に硬さが変化して、バルブとの摺動面で硬質粒子が浮き出る現象が抑制され摺動面が比較的平滑化し、チタン合金製バルブの酸素拡散硬化層への攻撃、破壊を防止できるためと考えられる。   By dispersing substantially spherical atomized Co-based intermetallic compound particles in the matrix phase, the partner's aggression against the valve is suppressed, and a decrease in the wear resistance of the valve can be suppressed. This is because, as described above, the atomized Co-based intermetallic compound particles themselves have a spherical shape, and a relatively large amount of a high alloy phase having a hardness of 300 to 600 HV0.1 can be formed in the matrix phase. The hardness gradually changes between the hard particles and the matrix phase, and the phenomenon of hard particles floating on the sliding surface with the valve is suppressed, the sliding surface becomes relatively smooth, and the oxygen diffusion of the titanium alloy valve This is considered to be able to prevent attack and destruction of the hardened layer.

また、硬質粒子としてのアトマイズ製Co基金属間化合物粒子は、20〜70μmの平均粒径と600〜1000HV0.1の硬さを有する粒子とする。平均粒径が20μm未満では、焼結処理中に基地相に拡散しやすく、硬質粒子としての効果が期待できなくなる。一方、70μmを超えて大きくなると、使用中に粒子の割れや欠陥が生じやすく、相手攻撃性が増大する傾向が強くなり、バルブおよびバルブシートの双方の耐摩耗性が低下する原因となる。また、硬さが600 HV0.1未満では、相手攻撃性は低いが、硬質粒子としての効果が期待できなくなる。一方、硬さが1000 HV0.1を超えると、使用中に粒子の割れや欠陥が生じやすくなり、バルブシートの耐摩耗性が低下するとともに、相手攻撃性が増大する。なお、粒子の硬さはマイクロビッカース硬さ計(荷重:0.1kgf)を用いて測定した値を使用し、粒子の平均粒径は、画像解析装置で測定した値を使用するものとする。   The atomized Co-based intermetallic compound particles as the hard particles are particles having an average particle diameter of 20 to 70 μm and a hardness of 600 to 1000 HV0.1. If the average particle size is less than 20 μm, it is easy to diffuse into the matrix phase during the sintering process, and the effect as hard particles cannot be expected. On the other hand, if the thickness exceeds 70 μm, particle cracking and defects are likely to occur during use, and the tendency to increase the partner's aggression becomes strong, which causes the wear resistance of both the valve and the valve seat to decrease. On the other hand, if the hardness is less than 600 HV0.1, the opponent's aggressiveness is low, but the effect as hard particles cannot be expected. On the other hand, if the hardness exceeds 1000 HV0.1, cracking and defects of particles are likely to occur during use, and the wear resistance of the valve seat is lowered and the opponent attack is increased. In addition, the value measured using the micro Vickers hardness meter (load: 0.1kgf) is used for the hardness of particle | grains, and the value measured with the image analyzer is used for the average particle diameter of particle | grains.

本発明では、アトマイズ製Co基金属間化合物粒子は、上記した硬さ、平均粒径を有するアトマイズ製Si−Cr−Mo系Co基金属間化合物粒子とすることが好ましい。Si−Cr−Mo系Co基金属間化合物粒子は、質量%で、Si:0.5〜4.0%、Cr:5.0〜20.0%、Mo:20.0〜40.0%を含み残部Coおよび不可避的不純物からなる組成を有する粒子である。Si、Cr、Mo含有量が、上記した範囲を外れると、金属間化合物量が所望の適正量範囲を外れ、上記した600〜1000HV0.1の硬さ範囲内に調整することが難しくなる。   In the present invention, the atomized Co-based intermetallic compound particles are preferably atomized Si—Cr—Mo-based Co-based intermetallic compound particles having the above-described hardness and average particle diameter. Si-Cr-Mo-based Co-based intermetallic compound particles contain, in mass%, Si: 0.5 to 4.0%, Cr: 5.0 to 20.0%, Mo: 20.0 to 40.0%, and the balance Co and inevitable impurities. Particles. If the Si, Cr, and Mo contents are out of the above range, the intermetallic compound amount is out of the desired appropriate amount range, and it becomes difficult to adjust the content within the above-described hardness range of 600 to 1000 HV0.1.

また本発明では、アトマイズ製Co基金属間化合物粒子は、上記した硬さ、平均粒径を有するアトマイズ製Si−Cr−Mo−Ni系Co基金属間化合物粒子としてもよい。Si−Cr−Mo−Ni系Co基金属間化合物粒子は、質量%で、Si:0.5〜4.0%、Cr:15.0〜35.0%、Mo:15.0〜35.0%、Ni:5.0〜20.0%を含み、残部Coおよび不可避的不純物からなる組成を有する粒子である。Si、Cr、Mo、Ni含有量が、上記した範囲を外れると、金属間化合物量が所望の適正量範囲を外れ、上記した600〜1000HV0.1の硬さ範囲内に調整することが難しくなる。   In the present invention, the atomized Co-based intermetallic compound particles may be atomized Si-Cr-Mo-Ni Co-based intermetallic compound particles having the above-described hardness and average particle diameter. Si-Cr-Mo-Ni Co-based intermetallic compound particles include, by mass, Si: 0.5 to 4.0%, Cr: 15.0 to 35.0%, Mo: 15.0 to 35.0%, Ni: 5.0 to 20.0%, It is a particle having a composition comprising the balance Co and inevitable impurities. If the Si, Cr, Mo, Ni content is out of the above range, the amount of intermetallic compound is out of the desired appropriate amount range, and it is difficult to adjust the content within the above-described hardness range of 600 to 1000 HV0.1. .

また、本発明で使用するバルブシート用の鉄基焼結合金材では、基地相が、質量%で、C:0.5〜1.5%を含み、さらにNi、Cr、Mo、Co、Cu、V、Wのうちから選ばれた1種または2種以上を合計で3.0〜10.0%含有し、残部Feおよび不可避的不純物からなる組成を有する。以下、組成における質量%は、単に%で記す。
C:0.5〜1.5%
Cは、基地中に含まれ、基地相の強化に寄与する元素であり、本発明では所望の強度を確保するために、0.5%以上の含有を必要とする。一方、1.5%を超える含有はセメンタイト形成傾向が強くなり、靭性が低下するとともに、過焼結が発生する。このため、Cは0.5〜1.5%の範囲に限定した。
Moreover, in the iron-based sintered alloy material for valve seats used in the present invention, the matrix phase contains, by mass%, C: 0.5 to 1.5%, and Ni, Cr, Mo, Co, Cu, V, W 1 to 2 or more types selected from among them are contained in a total of 3.0 to 10.0%, and the composition is composed of the remaining Fe and inevitable impurities. Hereinafter, the mass% in the composition is simply expressed as%.
C: 0.5-1.5%
C is an element that is contained in the base and contributes to strengthening of the base phase. In the present invention, it is necessary to contain 0.5% or more in order to ensure a desired strength. On the other hand, if the content exceeds 1.5%, the tendency to form cementite becomes strong, the toughness decreases, and oversintering occurs. For this reason, C was limited to the range of 0.5 to 1.5%.

Ni、Cr、Mo、Co、Cu、V、Wのうちから選ばれた1種または2種以上を合計:3.0〜10.0%
Ni、Cr、Mo、Co、Cu、V、Wはいずれも、基地相を強化し、バルブシートの硬さ、耐熱性、耐摩耗性の向上に寄与し、さらには基地の酸化鉄生成特性に影響する元素であり、選択して1種または2種以上を基地相に含有する。このような効果は、Ni、Cr、Mo、Co、Cu、V、Wのうちから選ばれた1種または2種以上の合計が3.0%以上で認められる。3.0%未満では酸化鉄生成特性はよいが、その他の特性向上は得られない。一方、10.0%を超えて含有しても、効果が飽和して含有量に見合う効果が期待できなくなり、経済的に不利となり、また酸化鉄生成特性が劣化する。このため、本発明では、Ni、Cr、Mo、Co、Cu、V、Wのうちから選ばれた1種または2種以上を合計で3.0〜10.0%の範囲に限定した。なお、好ましくは合計で4.0〜9.0%である。
Total of one or more selected from Ni, Cr, Mo, Co, Cu, V, and W: 3.0 to 10.0%
Ni, Cr, Mo, Co, Cu, V, and W all strengthen the matrix phase, contribute to improving the hardness, heat resistance, and wear resistance of the valve seat, and further improve the iron oxide generation characteristics of the matrix. It is an element which influences, selects and contains 1 type (s) or 2 or more types in a matrix phase. Such an effect is recognized when the total of one or more selected from Ni, Cr, Mo, Co, Cu, V, and W is 3.0% or more. If it is less than 3.0%, the iron oxide production characteristics are good, but other characteristics cannot be improved. On the other hand, if the content exceeds 10.0%, the effect is saturated and an effect commensurate with the content cannot be expected, which is economically disadvantageous, and the iron oxide production characteristics deteriorate. For this reason, in this invention, 1 type or 2 types selected from Ni, Cr, Mo, Co, Cu, V, and W was limited to the range of 3.0 to 10.0% in total. In addition, Preferably it is 4.0 to 9.0% in total.

なお、Niは、耐摩耗性の向上と、基地硬さの増加、および耐熱性の向上に寄与する元素であり、基地相では1.0〜6.0%含有することが好ましい。Crは、基地相の強化に寄与する元素であり、基地相では0.2〜3.0%含有することが好ましい。Moは、耐摩耗性の向上に寄与する元素であり、基地相では0.2〜2.0%含有することが好ましい。Coは、硬質粒子と基地相との接合を強化し、耐摩耗性向上に寄与する元素であり、基地相で1.0〜7.0%含有することが好ましい。V、Wは、基地相の強化と耐摩耗性を向上させる元素であり、それぞれ基地相では0.1〜1.0%含有することが好ましい。   Ni is an element that contributes to the improvement of wear resistance, the increase in matrix hardness, and the improvement of heat resistance, and it is preferable to contain 1.0 to 6.0% in the matrix phase. Cr is an element that contributes to strengthening of the matrix phase, and it is preferable to contain 0.2 to 3.0% in the matrix phase. Mo is an element that contributes to the improvement of wear resistance, and is preferably contained in the base phase in an amount of 0.2 to 2.0%. Co is an element that strengthens the bonding between the hard particles and the matrix phase and contributes to the improvement of wear resistance, and is preferably contained in the matrix phase in an amount of 1.0 to 7.0%. V and W are elements that improve the strengthening and wear resistance of the matrix phase, and preferably 0.1 to 1.0% each in the matrix phase.

本発明で使用するバルブシート用鉄基焼結合金材では、上記した成分以外の残部は、Feおよび不可避的不純物である。
本発明で使用するバルブシート用鉄基焼結合金材では、基地相中に分散したCo基金属間化合物粒子の周囲に、Co基金属間化合物粒子の合金成分が拡散して形成された高合金相を有する。この高合金相はCo、Ni、Mo、Cr、Siを多量に含有する相で、300〜600HV0.1の硬さを有する。このような高合金相を硬質粒子であるCo基金属間化合物粒子の周囲に形成することにより、硬質粒子と基地相との間の硬さ変化を段階的とすることができ、バルブとの摺動に際し摺動面で硬質粒子が浮き出る現象を抑制することができ、チタン合金製バルブへの相手攻撃性が低下することができる。
In the iron-based sintered alloy material for valve seats used in the present invention, the balance other than the above components is Fe and inevitable impurities.
In the iron-based sintered alloy material for a valve seat used in the present invention, a high alloy formed by diffusing the alloy component of the Co-based intermetallic compound particles around the Co-based intermetallic compound particles dispersed in the matrix phase. Has a phase. This high alloy phase is a phase containing a large amount of Co, Ni, Mo, Cr, and Si, and has a hardness of 300 to 600 HV0.1. By forming such a high alloy phase around the Co-based intermetallic compound particles, which are hard particles, the change in hardness between the hard particles and the matrix phase can be made gradual, and sliding with the valve can be performed. It is possible to suppress the phenomenon that the hard particles are lifted on the sliding surface during the movement, and the opponent attack property to the titanium alloy valve can be reduced.

なお、高合金相は、8〜35面積%程度を存在させることが好ましい。この存在範囲を外れると上記した効果が期待できなくなる。
また、本発明で使用するバルブシート用鉄基焼結合金材では、上記した硬質粒子に加えてさらに固体潤滑剤粒子を分散させてもよい。固体潤滑剤粒子は、バルブシートの被削性の向上、運転時のバルブとの凝着の抑制に寄与する。このような効果は、質量%で0.2%以上の分散で認められる。固体潤滑剤粒子が質量%で0.2%未満では、被削性が劣化傾向を示し、さらにバルブとの凝着発生が促進されやすくなる傾向となる。一方、3.0%を超えて分散させても、効果が飽和し含有量に見合う効果が期待できなくなり経済的に不利となるとともに、焼結体強度が低下する。このため、固体潤滑剤は質量%で0.2〜3.0%に限定することが好ましい。固体潤滑剤としては、MnS等の硫化物のうちの1種以上、あるいはCaF2等の弗化物のうちの1種以上、あるいはそれらの混合とすることが好ましい。
In addition, it is preferable to make a high alloy phase exist about 8-35 area%. If it is out of this existence range, the above-mentioned effect cannot be expected.
Moreover, in the iron-based sintered alloy material for valve seats used in the present invention, solid lubricant particles may be further dispersed in addition to the hard particles described above. The solid lubricant particles contribute to improvement of the machinability of the valve seat and suppression of adhesion with the valve during operation. Such an effect is recognized with a dispersion of 0.2% or more by mass%. If the solid lubricant particles are less than 0.2% by mass, the machinability tends to deteriorate, and the adhesion with the valve tends to be promoted. On the other hand, even if the content exceeds 3.0%, the effect is saturated and an effect commensurate with the content cannot be expected, which is economically disadvantageous and the sintered body strength is reduced. For this reason, the solid lubricant is preferably limited to 0.2 to 3.0% by mass. As solid lubricant, one or more of the sulfides such as MnS, or CaF 2, etc. one or more of the fluorides, or it is preferable that the mixing thereof.

つぎに、本発明のバルブシートの好ましい製造方法について説明する。
まず、原料粉として、基地相を形成する、純鉄粉、合金鉄粉(合金鋼粉を含む)および合金元素粉と、硬質粒子として、好ましくは上記した粒径、硬さ、組成の硬質粒子粉と、あるいはさらに固体潤滑剤粉とを、上記した基地相組成、硬質粒子質量%、固体潤滑剤粒子質量%となるように、配合し、混合、混練して、混合粉とする。
Below, the preferable manufacturing method of the valve seat of this invention is demonstrated.
First, pure iron powder, alloy iron powder (including alloy steel powder) and alloy element powder that form a matrix phase as raw material powder, and hard particles, preferably hard particles having the above-mentioned particle size, hardness, and composition Powder, or further solid lubricant powder is blended, mixed and kneaded so as to have the above-mentioned matrix phase composition, hard particle mass%, and solid lubricant particle mass% to obtain a mixed powder.

基地相を形成する原料粉は、純鉄粉に合金元素粉を混合しても、合金鉄粉あるいは合金鋼粉に合金元素粉を混合しても、また純鉄粉、合金鉄粉あるいは合金鋼粉に合金元素粉を混合しても、上記した基地相組成となるように配合できればいずれでもよい。なお、合金元素の均一分散という観点からは合金鉄粉、合金鋼粉を用いることが好ましい。
ついで、混合粉を、金型に充填したのち、成形プレス等により圧縮・成形し成形体とする。ついで、得られた成形体を、アンモニア分解ガス、真空等の保護雰囲気中で、好ましくは1000〜1200℃の温度範囲に加熱して焼結し、鉄基焼結合金材とする。
The raw material powder that forms the matrix phase can be pure iron powder mixed with alloy element powder, alloy iron powder or alloy steel powder with alloy element powder, pure iron powder, alloy iron powder or alloy steel. Even if alloy element powder is mixed with the powder, any powder may be used as long as it can be blended so as to have the matrix phase composition described above. From the viewpoint of uniform dispersion of alloy elements, it is preferable to use alloy iron powder or alloy steel powder.
Next, after the mixed powder is filled in a mold, it is compressed and molded by a molding press or the like to obtain a molded body. Subsequently, the obtained molded body is heated and sintered in a temperature range of 1000 to 1200 ° C. in a protective atmosphere such as ammonia decomposition gas and vacuum to obtain an iron-based sintered alloy material.

このようにして得られた鉄基焼結合金材を、切削、研削等の加工により所定寸法形状の内燃機関用バルブシートとする。
本発明の内燃機関用バルブとバルブシートの組合せでは、バルブはチタン合金製のバルブとする。本発明では使用するチタン合金の種類はとくに限定する必要はなく、公知のチタン合金がいずれも使用できるが、使用環境、量産性、製造コスト等の観点から、吸気側バルブに、一般的な、Ti−6Al−4V合金(質量%で、6.0%Al、4.0%V、残部Tiおよび不可避的不純物)を、排気側バルブにTi−6Al−2Sn−4Zr−2Mo−0.2Si合金(質量%で、6.0%Al、2.0%Sn、4.0%Zr、2.0%Mo、0.2%Si、残部Tiおよび不可避的不純物)またはTi−2.7Sn−4Zr−0.4Mo−0.5Si合金(質量%で、2.7%Sn、4.0%Zr、0.4%Mo、0.5%Si、残部Tiおよび不可避的不純物)を使用することが好ましい。なお、バルブは、上記したチタン合金で少なくともバルブフェース部を構成してもよい。
The iron-based sintered alloy material thus obtained is made into a valve seat for an internal combustion engine having a predetermined size and shape by processing such as cutting and grinding.
In the combination of the valve for an internal combustion engine and the valve seat according to the present invention, the valve is a titanium alloy valve. In the present invention, the type of titanium alloy to be used is not particularly limited, and any known titanium alloy can be used. From the viewpoint of use environment, mass productivity, manufacturing cost, etc. Ti-6Al-4V alloy (mass%, 6.0% Al, 4.0% V, balance Ti and inevitable impurities), Ti-6Al-2Sn-4Zr-2Mo-0.2Si alloy (mass%, 6.0% Al, 2.0% Sn, 4.0% Zr, 2.0% Mo, 0.2% Si, balance Ti and inevitable impurities) or Ti-2.7Sn-4Zr-0.4Mo-0.5Si alloy (mass%, 2.7% Sn, 4.0% Zr, 0.4% Mo, 0.5% Si, the balance Ti and inevitable impurities) are preferably used. The valve may comprise at least the valve face portion with the above-described titanium alloy.

さらに、本発明で使用するチタン製バルブは、少なくともバルブシートとの摺動面(バルブフェース部)にマイクロビッカース硬さで400HV0.01以上の酸素拡散硬化層を有することが好ましい。このような酸素拡散硬化層の形成により、バルブの耐摩耗性が向上する。酸素拡散硬化層の硬さがマイクロビッカース硬さで400HV0.01未満では、バルブシートから攻撃を受けてバルブの過大摩耗を生じる可能性が高くなる。なお、酸素拡散硬化層の厚さは5〜20μmとすることが好ましい。この範囲を外れる厚さでは効果が少ないか、あるいは靭性が低下し所望の効果が期待できなくなる場合がある。   Furthermore, the titanium valve used in the present invention preferably has an oxygen diffusion hardened layer having a micro Vickers hardness of 400 HV0.01 or more on at least the sliding surface (valve face portion) with the valve seat. By forming such an oxygen diffusion hardened layer, the wear resistance of the valve is improved. If the oxygen diffusion hardened layer has a micro Vickers hardness of less than 400 HV0.01, there is a high possibility of excessive wear of the valve due to attack from the valve seat. The thickness of the oxygen diffusion hardened layer is preferably 5 to 20 μm. If the thickness is out of this range, the effect may be small, or the toughness may decrease and the desired effect may not be expected.

なお、好ましくは上記した組成のチタン合金の鋳造材、鍛造材、あるいは成形材等から切削、研削等の加工により所定寸法形状の内燃機関用バルブとすることが好ましい。また、内燃機関用バルブには、さらに大気雰囲気中で加熱する酸化処理を施し、所望厚さの酸素拡散硬化層を形成することもできる。   In addition, it is preferable that a valve for an internal combustion engine having a predetermined size and shape is formed from a cast material, a forged material, a molded material, or the like of the titanium alloy having the above-described composition by machining such as cutting or grinding. In addition, the internal combustion engine valve may be further subjected to an oxidation treatment that is heated in an air atmosphere to form an oxygen diffusion hardened layer having a desired thickness.

原料粉として、合金鉄粉または合金鋼粉、および/または純鉄粉に、合金元素粉、および硬質粒子粉を、あるいはさらに固体潤滑剤粒子粉を、表1に示すバルブシート組成となるように配合し、混合、混練して混合粉とした。なお、一部では固体潤滑剤粒子粉は配合しなかった。使用した硬質粒子粉の種類、組成を表2に、固体潤滑剤粉の種類を表3にそれぞれ示す。   As a raw material powder, alloy iron powder or alloy steel powder, and / or pure iron powder, alloy element powder and hard particle powder, or further solid lubricant particle powder so as to have the valve seat composition shown in Table 1. Blended, mixed and kneaded to obtain a mixed powder. In some cases, solid lubricant particle powder was not blended. Table 2 shows the type and composition of the hard particle powder used, and Table 3 shows the type of solid lubricant powder.

ついで、これら混合粉を、金型に充填し、成形プレスにより圧縮・成形し圧粉体とした。
ついで、これら圧粉体に、1000〜1200℃の保護雰囲気中(還元ガス雰囲気)で焼結処理を施し、鉄基焼結合金材とした。
図3、図4に得られた鉄基焼結合金材の光学顕微鏡組織をスケッチ図として示す。本発明例のバルブシートでは硬質粒子が球形状を呈し、かつ硬質粒子の周囲に高合金相を有していることがわかる。
Subsequently, these mixed powders were filled into a mold and compressed and molded by a molding press to obtain a green compact.
Subsequently, these green compacts were sintered in a protective atmosphere (reducing gas atmosphere) at 1000 to 1200 ° C. to obtain an iron-based sintered alloy material.
FIG. 3 and FIG. 4 show the optical microscope structure of the obtained iron-based sintered alloy material as a sketch diagram. In the valve seat of the example of the present invention, it can be seen that the hard particles have a spherical shape and have a high alloy phase around the hard particles.

また、得られた鉄基焼結合金材から、切削、研削加工によりバルブシート(寸法形状寸法:φ30×φ27×7mm)を加工した。
表4に示す種類のチタン合金のインゴット材から、鋳造、切削、研削加工により、上記したバルブシートに適合するバルブを加工した。一部のバルブには、大気中で700℃に300分間加熱する酸化処理を施し、表面に酸素拡散硬化層(5〜10μm)を形成した。なお、バルブ当たり面の硬さをマイクロビッカース硬さ計(荷重:0.01kgf)で測定した。
Further, a valve seat (size and shape: φ30 × φ27 × 7 mm) was processed from the obtained iron-based sintered alloy material by cutting and grinding.
From the titanium alloy ingot material shown in Table 4, a valve suitable for the above-described valve seat was processed by casting, cutting, and grinding. Some valves were subjected to an oxidation treatment by heating at 700 ° C. for 300 minutes in the atmosphere to form an oxygen diffusion hardened layer (5 to 10 μm) on the surface. The hardness of the contact surface of the valve was measured with a micro Vickers hardness meter (load: 0.01 kgf).

得られたこれらバルブシート、バルブを表1に示すように組合せ、図5に示す単体リグ摩耗試験機を用いて単体リグ摩耗試験を実施した。バルブシート1をシリンダヘッド相当品の治具2に圧入したのち、試験機に装着した熱源3によりバルブ4およびバルブシート1を加熱しながらクランク機構によりバルブ4を上下させて、試験した。なお、試験後、バルブおよびバルブシートの摩耗量を測定した。試験条件はつぎの通りとした。   These valve seats and valves thus obtained were combined as shown in Table 1, and a single rig wear test was performed using a single rig wear tester shown in FIG. After the valve seat 1 was press-fitted into the jig 2 corresponding to the cylinder head, the valve 4 was moved up and down by the crank mechanism while the valve 4 and the valve seat 1 were heated by the heat source 3 mounted on the testing machine, and the test was performed. In addition, the amount of wear of the valve and the valve seat was measured after the test. The test conditions were as follows.

試験温度:400℃(シート面)
試験時間:9h
カム回転数:3000rpm
バルブ回転数:20rpm
スプリング荷重:35kgf(345 N)(セット時)
リフト量:7.5mm
得られた結果を表5および図1〜図2に示す。
Test temperature: 400 ° C (sheet surface)
Test time: 9h
Cam rotation speed: 3000rpm
Valve speed: 20rpm
Spring load: 35kgf (345 N) (when set)
Lift amount: 7.5mm
The obtained results are shown in Table 5 and FIGS.

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吸気側の組合せでは、本発明例の組合せであれば、バルブシートの摩耗量は20μm以下、バルブの摩耗量は10μm以下であり、耐摩耗性に優れ、耐久性に優れたバルブとバルブシートの組合せとなっている。本発明例で使用したバルブシートの相手攻撃性が低いことを示している。また、排気側の組合せにおいても、本発明例の組合せであれば、バルブシートの摩耗量は20μm以下、バルブの摩耗量は10μm以下であり、耐摩耗性に優れたバルブとバルブシートの組合せとなっている。   As for the combination on the intake side, the wear amount of the valve seat is 20 μm or less, the wear amount of the valve is 10 μm or less, and the wear of the valve and valve seat is excellent in durability and durability. It is a combination. It shows that the opponent attack of the valve seat used in the example of the present invention is low. Also, in the exhaust side combination, if the combination of the present invention example, the wear amount of the valve seat is 20 μm or less, the wear amount of the valve is 10 μm or less, and the combination of the valve and valve seat having excellent wear resistance It has become.

一方、本発明の範囲を外れる比較例の組合せでは、吸気側、排気側のいずれにおいても、バルブシートの摩耗量あるいはバルブの摩耗量のいずれか、あるいは両方が大きくなり、バルブシートの相手攻撃性が大きくなり、実機において所望の耐摩耗性を維持できない可能性が高いと推察される。   On the other hand, in the combination of comparative examples outside the scope of the present invention, either the valve seat wear amount or the valve wear amount, or both increases on both the intake side and the exhaust side. It is assumed that there is a high possibility that the desired wear resistance cannot be maintained in the actual machine.

実施例におけるバルブシート、バルブの摩耗量を比較して示すグラフである。It is a graph which compares and shows the amount of wear of a valve seat and a valve in an example. 実施例におけるバルブシート、バルブの摩耗量を比較して示すグラフである。It is a graph which compares and shows the amount of wear of a valve seat and a valve in an example. 本発明例のバルブシート(バルブシートNo.4)の金属組織のスケッチ図である。It is a sketch figure of the metal structure of the valve seat (valve seat No. 4) of the example of the present invention. 比較例のバルブシート(バルブシートNo.22)の金属組織のスケッチ図である。It is a sketch figure of the metal structure of the valve seat (valve seat No. 22) of a comparative example. 単体リグ摩耗試験機の概略説明図である。It is a schematic explanatory drawing of a single rig abrasion tester.

符号の説明Explanation of symbols

1 バルブシート
2 治具
3 熱源
4 バルブ
1 Valve seat 2 Jig 3 Heat source 4 Valve

Claims (5)

内燃機関におけるバルブとバルブシートの組合せであって、前記バルブが、チタン合金製バルブであり、前記バルブシートが、基地相中に硬質粒子として、20〜70μmの平均粒径と600〜1000HV0.1の硬さを有するアトマイズ製Co基金属間化合物粒子を質量%で10.0〜40.0%分散させ、前記基地相が、質量%で、C:0.5〜1.5%を含み、さらにNi、Cr、Mo、Co、Cu、V、Wのうちから選ばれた1種または2種以上を合計で3.0〜10.0%含有し、残部Feおよび不可避的不純物からなる組成を有し、かつ前記Co基金属間化合物粒子の周囲に該Co基金属間化合物粒子の合金成分の拡散により形成された高合金相を有する鉄基焼結合金材からなることを特徴とする内燃機関用バルブとバルブシートの組合せ。   A combination of a valve and a valve seat in an internal combustion engine, wherein the valve is a titanium alloy valve, and the valve seat is an average particle size of 20 to 70 μm and 600 to 1000 HV0.1 as hard particles in the base phase. Atomized Co-based intermetallic compound particles having a hardness of 0.04 to 40.0% are dispersed in mass%, the matrix phase contains C: 0.5 to 1.5% in mass%, and Ni, Cr, Mo, Co , Cu, V, W selected from a total of 3.0 to 10.0%, a composition comprising the balance Fe and inevitable impurities, and the Co-based intermetallic compound particles A combination of a valve for an internal combustion engine and a valve seat, comprising an iron-based sintered alloy material having a high alloy phase formed by diffusion of an alloy component of the Co-based intermetallic compound particles around. 前記アトマイズ製Co基金属間化合物粒子が、質量%で、Si:0.5〜4.0%、Cr:5.0〜20.0%、Mo:20.0〜40.0%を含み残部Coおよび不可避的不純物からなる組成を有するアトマイズ製Si−Cr−Mo系Co基金属間化合物粒子、または、Si:0.5〜4.0%、Cr:15.0〜35.0%、Mo:15.0〜35.0%、Ni:5.0〜20.0%を含み、残部Coおよび不可避的不純物からなる組成を有するアトマイズ製Si−Cr−Mo−Ni系Co基金属間化合物粒子であることを特徴とする請求項1に記載の内燃機関用バルブとバルブシートの組合せ。   The atomized Co-based intermetallic compound particles have a composition comprising, by mass%, Si: 0.5 to 4.0%, Cr: 5.0 to 20.0%, Mo: 20.0 to 40.0%, and the balance Co and inevitable impurities. Si-Cr-Mo-based Co-based intermetallic compound particles, or Si: 0.5 to 4.0%, Cr: 15.0 to 35.0%, Mo: 15.0 to 35.0%, Ni: 5.0 to 20.0%, remaining Co and inevitable The combination of a valve for an internal combustion engine and a valve seat according to claim 1, wherein the combination is an atomized Si-Cr-Mo-Ni Co-based intermetallic compound particle having a composition comprising impurities. 前記バルブシートが、前記基地相中に前記硬質粒子に加えてさらに、固体潤滑剤粒子を質量%で0.2〜3.0%分散させることを特徴とする請求項1または2に記載の内燃機関用バルブとバルブシートの組合せ。   The internal combustion engine valve according to claim 1 or 2, wherein the valve seat further disperses 0.2 to 3.0% by mass of solid lubricant particles in the matrix phase in addition to the hard particles. Combination of valve seats. 前記チタン合金製バルブが、Ti−6Al−4V合金製バルブ、Ti−6Al−2Sn−4Zr−2Mo−0.2Si合金製バルブまたはTi−2.7Sn−4Zr−0.4Mo−0.5Si合金製バルブとすることを特徴とする請求項1ないし3のいずれかに記載の内燃機関用バルブとバルブシートの組合せ。   The titanium alloy valve is a Ti-6Al-4V alloy valve, a Ti-6Al-2Sn-4Zr-2Mo-0.2Si alloy valve or a Ti-2.7Sn-4Zr-0.4Mo-0.5Si alloy valve. The combination of a valve for an internal combustion engine and a valve seat according to any one of claims 1 to 3. 前記チタン合金製バルブが、硬さ:400HV0.1以上の酸素拡散硬化層を有することを特徴とする請求項1ないし4のいずれかに記載の内燃機関用バルブとバルブシートの組合せ。   The combination of a valve for an internal combustion engine and a valve seat according to any one of claims 1 to 4, wherein the titanium alloy valve has an oxygen diffusion hardened layer having a hardness of 400HV0.1 or more.
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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2011094605A (en) * 2009-10-30 2011-05-12 Man Diesel & Turbo Filial Af Man Diesel & Turbo Se Tyskland Exhaust valve spindle for internal combustion engine, and method for manufacturing the same
WO2011105620A1 (en) * 2010-02-26 2011-09-01 新日本製鐵株式会社 Automotive engine valve comprising titanium alloy and having excellent heat resistance
CN104165073A (en) * 2014-07-21 2014-11-26 河北华北柴油机有限责任公司 Cylinder cover capable of preventing valve retainer from falling off

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2011094605A (en) * 2009-10-30 2011-05-12 Man Diesel & Turbo Filial Af Man Diesel & Turbo Se Tyskland Exhaust valve spindle for internal combustion engine, and method for manufacturing the same
WO2011105620A1 (en) * 2010-02-26 2011-09-01 新日本製鐵株式会社 Automotive engine valve comprising titanium alloy and having excellent heat resistance
JP2011179375A (en) * 2010-02-26 2011-09-15 Nippon Steel Corp Automotive engine valve comprising titanium alloy and having excellent heat resistance
EP2540998A1 (en) * 2010-02-26 2013-01-02 Nippon Steel Corporation Automotive engine valve comprising titanium alloy and having excellent heat resistance
EP2540998A4 (en) * 2010-02-26 2014-08-06 Nippon Steel & Sumitomo Metal Corp Automotive engine valve comprising titanium alloy and having excellent heat resistance
CN104165073A (en) * 2014-07-21 2014-11-26 河北华北柴油机有限责任公司 Cylinder cover capable of preventing valve retainer from falling off

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