JPS61117254A - Ferrous sintered alloy for valve seat - Google Patents

Abstract

PURPOSE:To obtain the ferrous sintered alloy for a valve seat having a characteristic balanced between wear resistance and attackability to opposite materials, by dispersing, in a specific weight ratio, the hard particles consisting of Co-base alloy in the iron matrix mainly composed of pearlite. CONSTITUTION:The ferrous sintered alloy for a valve seat is obtained by dispersing, by 5-30% by weight ratio, the hard particles composed of the Co-base alloy consisting of, by weight, 0.5-2% C, 5-30% Ni, 5-15% Mo, 10-40% Cr, and the balance Co in the iron matrix mainly composed of pearlite. The total composition consists of, by weight, 0.65-23% Co, 0.5-12% Cr, 0.25-4.5% Mo, 0.25-9% Ni, 1-2.8% C, and the balance Fe with inevitable impurities, which is impregnated with 1-20wt% Pb, if necessary.

Description

【発明の詳細な説明】 〔産業上の利用分野〕 本発明は内燃機関のバルブシート用焼結合金の性能改善
に係シ、よシ詳しくは自身の耐摩耗性を高め、かつ相手
部材に対する攻撃性を弱めた鉄系焼結合金に関する。[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to improving the performance of a sintered alloy for valve seats of internal combustion engines, and more particularly, to improving the wear resistance of the sintered alloy and preventing attacks against mating members. Concerning iron-based sintered alloys with weakened properties.

〔従来技術〕[Prior art]

内燃機関のバルブシートには高温での耐摩耗性を高める
ため、Ｃｒ、ＮｉｔＣｏｌＭｏ等の合金元素を添加した
鉄系焼結合金が多用されつ一＼おる。In order to improve wear resistance at high temperatures, iron-based sintered alloys to which alloying elements such as Cr and NitColMo are added are frequently used in valve seats of internal combustion engines.

ところで、バルブシートの材質の選択は、相手部材す表
わちエンジンバルブとの相関において決定されるべきも
ので、この選択を誤ると自身の耐摩耗性を弱めるばかり
か、相手部材に対する攻撃性を増して、バルブ機構全体
に思わしくない影響を与えることになる。By the way, the selection of the material for the valve seat should be determined in relation to the mating member, that is, the engine valve.If this selection is incorrect, it will not only weaken its own wear resistance, but also become aggressive towards the mating member. In addition, this will have an undesirable effect on the entire valve mechanism.

例えば従来エンジンバルブとしては耐摩耗性を高めるた
め、ステライト等の盛会を施したものが多用されている
が、近年原価低減の要求からバルブ盛会を廃止する動き
にある。このような背景のもとに従来のような例えばフ
ェロモリブデン等の金属間化合物または複合炭化物を添
加して極度に耐摩耗性を高めたバルブシートをそのま＼
使用するとエンジンバルブの摩耗を増大させる結果とな
る。For example, conventionally, engine valves have often been coated with stellite or the like in order to improve wear resistance, but in recent years there has been a movement to eliminate valve fillers due to demands for cost reduction. Against this background, conventional valve seats with extremely high wear resistance made by adding intermetallic compounds such as ferromolybdenum or composite carbides, for example, can be used as is.
Use results in increased wear on engine valves.

〔発明が解決しようとする問題点〕[Problem that the invention seeks to solve]

本発明は上記の盛会処理等によル耐摩耗性が高められて
ない汎用エンジンバルブ（例エバＪＩＳ　５ＵＨ５１，
５ＵＨ５裏）を相手にした場合にも相手を摩耗し、ちる
いは自身の摩耗を著しく増大させることのないよう圧し
ようとするもので。The present invention applies to general-purpose engine valves whose wear resistance has not been improved by the above-mentioned process (e.g. EVA JIS 5UH51,
5UH5 Ura), it wears out the other party and tries to apply pressure without significantly increasing the wear on itself.

耐摩耗性と相手攻撃性との適度のバランスのとれたバル
ブシート用鉄系焼結合金の提供を目的とするものである
。The object of the present invention is to provide an iron-based sintered alloy for valve seats that has an appropriate balance between wear resistance and attack resistance.

〔問題を解決するための手段〕[Means to solve the problem]

本発明バルブシート用鉄系焼結合金は重量比で１ないし
ｚ２チの炭素（Ｃ−）を含むパーライト主体の鉄（Ｆｅ
　）基地中に、重量比で炭素（Ｃ）：０．５〜２．０　
％、　＝ツヶル（Ｎｉ）：　５〜４０％、　モリブデ７
　（Ｍｏ）　：　５〜１５ｔｓ、り＊ム（Ｃｒ）　：　
１０〜４０優、残部コバルト（Ｃｏ　）からなる硬質粒
子を重量比として５ないし５０％分散させ、全体の組成
をＣｏ　　Ｉ］、６５〜２３％、Ｃｒ　：　０．５〜１
２　％。The iron-based sintered alloy for valve seats of the present invention is pearlite-based iron (Fe) containing 1 to z2 carbon (C-) by weight.
) Carbon (C): 0.5 to 2.0 by weight in the base
%, = Tsugaru (Ni): 5-40%, Molybde 7
(Mo): 5-15ts, Ri*mu (Cr):
Hard particles consisting of 10 to 40% cobalt (Co), the balance being 5 to 50% by weight, are dispersed, and the overall composition is Co2, 65 to 23%, and Cr: 0.5 to 1.
2%.

ＭＯ：ＩＩＬ２５〜４５　％、Ｎｉ：０．５５〜９％、
Ｃ：　１．０〜２．８％、残部Ｆ・及び不可避不純物と
し、さらに所望によシ全重量比にして１ないし２０％の
鉛（Ｐｂ）を含浸させたことを特徴とするものである。MO: IIL25-45%, Ni: 0.55-9%,
C: 1.0 to 2.8%, the balance being F and unavoidable impurities, and is characterized by being impregnated with lead (Pb) in an amount of 1 to 20% by total weight, if desired. .

〔作　用〕[For production]

上記のＣｏ基合金硬質粒子は３０ないし１５０μの粒径
を有し、市販で求めることができる。The above Co-based alloy hard particles have a particle size of 30 to 150 μm and can be obtained commercially.

そしてこれをＣを含むＦｅ基地中に分散させたのは、バ
ルブシートの耐摩耗性を適度〈高めるためであ）、合金
中のＣｏの一部が基地中Ｉ／ｃ拡散して粒子の周囲に拡
散層を形成し、粒子と基地との結合力を増して皺粒子の
脱落を防ぐ作用がある。そして５チ未満では耐摩耗性が
小さく、ｓａｄを越えると相手バルブを著しく摩耗させ
るため５ないし５Ｏｑｋの混合率とした。The reason why this was dispersed in the Fe matrix containing C was to moderately (increase) the wear resistance of the valve seat, and part of the Co in the alloy diffused into the matrix and around the particles. This has the effect of forming a diffusion layer on the surface, increasing the binding force between the particles and the base, and preventing the wrinkled particles from falling off. If it is less than 5 inches, the wear resistance is low, and if it exceeds sad, the mating valve will be significantly worn, so the mixing ratio was set to 5 to 5 Oqk.

一方、Ｆｅ基地中に含まれるＣは基地のＦｅＫ固溶して
パーライトを形成し、焼結合金の硬さを高め、耐摩耗性
を向上させるとともに、未反応の遊離黒鉛がある程度基
地中に内在することにより、潤滑効果が発揮される。但
し１優以下では上記の効果が現れず、２２％以上では遊
離黒鉛が多ぐなって基地の強度が低下するため１ないし
２．２％が好ましい。On the other hand, C contained in the Fe base forms a solid solution with FeK in the base to form pearlite, increasing the hardness of the sintered alloy and improving wear resistance. By doing so, a lubricating effect is exhibited. However, if it is less than 1%, the above effect will not be exhibited, and if it is more than 22%, free graphite will increase and the strength of the base will decrease, so 1 to 2.2% is preferable.

次に硬質粒子中に含まれる成分の限定理由について述べ
る。Next, the reasons for limiting the components contained in the hard particles will be described.

Ｃｒは炭素と化合して炭化物を形成すると共に一部がＣ
ｏと合金を形成し、Ｐ質粒子の硬さを向上させる効果を
有しているが１０％以下では上記の効果が不十分であり
、４０チ以上になると粒子内の平衡を保つために一部の
Ｃｒが粒子外に拡散し、該粒子内に空隙を生じて脆くな
る。また粒子内の炭化物の量が多くなって相手部材に対
する攻撃性を増す。Cr combines with carbon to form carbide, and part of it is carbon.
It forms an alloy with P-based particles and has the effect of improving the hardness of the P-based particles, but if it is less than 10%, the above effect is insufficient, and if it is more than 40%, it is necessary to increase the hardness of the particles. Cr diffuses out of the particles, creating voids within the particles and making them brittle. In addition, the amount of carbide in the particles increases, increasing the aggressiveness toward the mating member.

Ｎｏは炭素と化合して炭化物を形成し、一部は固溶して
硬質粒子の固さを増すが、５悌以下ではその効果が発揮
されず、１５チ以上では硬くなシすぎて相手部材を攻撃
するので５ないし１５％とした。No combines with carbon to form carbide, and some of it dissolves in solid solution to increase the hardness of the hard particles, but if it is less than 5 degrees, its effect is not exhibited, and if it is more than 15 degrees, it is not too hard and cannot be used as a mating member. Since it attacks, it was set at 5 to 15%.

ＣはＣｒｅＭｏと化合して炭化物を形成し、硬質粒子の
硬さを増すが０．５％以下ではその効果が発揮されず、
２％以上では炭化物の量が多過ぎて脆くなるのでａ５な
？ｌ、２　％とした。C combines with CreMo to form carbides and increases the hardness of hard particles, but if it is less than 0.5%, the effect is not exhibited.
If it is more than 2%, the amount of carbide will be too large and it will become brittle, so why not A5? l, 2%.

ＮｉはＣｏ基地に固溶して強度向上及び耐蝕性向上の効
果を有するが５％以下では効果がなく、３０チ以上では
効果が頭打ちになるため５ないし３０％とした。Ni is dissolved in the Co matrix and has the effect of improving strength and corrosion resistance, but if it is less than 5%, it has no effect, and if it is more than 30 tack, the effect reaches a plateau, so the content is set to 5 to 30%.

上記のような基地と硬質粒子とからなる鉄系焼結合金の
全組成はＣ：ｔＧ〜２．８チ、ＣＯ：α６５〜２５チ、
Ｃｒ：α５〜４２％、Ｍｏ　：　（１２５〜４．５　係
、Ｎｉ　：　Ｑ、２５〜９チ、残部がＦｅ及び不可避不
純物となる。The total composition of the iron-based sintered alloy consisting of the base and hard particles as described above is C: tG~2.8CH, CO: α65~25CH,
Cr: α5 to 42%, Mo: (125 to 4.5%), Ni: Q, 25 to 9%, the remainder being Fe and inevitable impurities.

上記構成の鉄系焼結合金にさらにｐｂを含浸させるど、
焼結合金の表面にｐｂの酸化物層が形成され、その潤滑
作用によってバルブシートと相手パルプ相互の耐摩耗性
が向上する。但し含浸量が１憾未満ではその効果が小さ
く、２０チを越えると基地が軟化して耐摩耗性が低下す
るため１ないし２０９６が好ましい。By further impregnating the iron-based sintered alloy with the above structure with PB,
A PB oxide layer is formed on the surface of the sintered alloy, and its lubricating action improves the mutual wear resistance between the valve seat and the mating pulp. However, if the impregnation amount is less than 1 inch, the effect will be small, and if it exceeds 20 inches, the base will become soft and the wear resistance will decrease, so 1 to 2096 is preferable.

このような本発明焼結合金はパーライト主体の鉄基地中
にＣｏ基合金よりなる硬質粒子を５ないし５０％、さら
に所望により潤滑剤としてステアリン酸亜鉛をα５ない
し１憾配合、混合した後、金型内に充填して成形圧力６
ないし７ｔ／ｃｉｌで成形し、これを還元性雰囲気中、
１１００℃ないし１２５０℃で３０ないし６０分間焼結
することによって得られる。また必要に応じて該焼結体
をｐｂ塊に接触させ、還元性雰囲気中、１００口ないし
１１００℃で３０ないし６０分間加熱し、焼結体内に１
ないし２０壬のｐｂを溶浸分散させる。The sintered alloy of the present invention is prepared by mixing 5 to 50% of hard particles made of Co-based alloy in an iron base mainly composed of pearlite, and further adding α5 to 1 portion of zinc stearate as a lubricant if desired. Fill the mold and molding pressure 6
to 7t/cil, and then molded in a reducing atmosphere.
It is obtained by sintering at 1100°C to 1250°C for 30 to 60 minutes. Further, if necessary, the sintered body is brought into contact with a PB lump and heated at 100°C to 1100°C for 30 to 60 minutes in a reducing atmosphere, so that the sintered body
Infiltrate and disperse 20 to 20 tons of PB.

〔実施例〕〔Example〕

以下、本発明の実施例を比較例と対比しつ＼説明する。 Examples of the present invention will be explained below in comparison with comparative examples.

実施例１゜ 重量比で２０％Ｃｒ−１０Ｓ　Ｍｏ−７％　Ｎｉ−１’
ＡＣ−残部Ｃｏからなる一１００メツシュＣｏ基合金粉
末が２０係、ステアリン酸亜鉛が１８１゜−３２５メツ
シユ黒鉛粉末が１．２憾となるように配合・混合し、こ
れを金型に充填して成形圧カフ　１ｍ／ｄｉで圧縮成形
して成形体を得、次に該成形体をアンモニア分解ガス中
で１１５０℃Ｘ６０分間加熱・焼結した。Example 1゜20% Cr-10S Mo-7% Ni-1' by weight
A 1100-mesh Co-based alloy powder consisting of AC-the remainder Co was blended and mixed to a ratio of 20 parts, a 181°-325 mesh graphite powder of zinc stearate was 1.2 parts, and this was filled into a mold. A molded body was obtained by compression molding at a molding pressure cuff of 1 m/di, and then the molded body was heated and sintered at 1150° C. for 60 minutes in ammonia decomposition gas.

その後、上記のごとくして得た焼結体をバルブシートに
加工し、該バルブシートを排気量２０００ｃｃ、４気筒
エンジンのアルミニウム合金製シリンダヘッドに排気弁
座として圧入・組付け、台上耐久試験に供した・ 台上耐久試験は有鉛ガソリンを用ｈ、６６０ａｒ、ｐ、
ｍ、、全負荷で２００時間継続した。この時の相手パル
プＫＦｉ盛金なしの汎用パルプ（ＪＩＳＳＵＨ５）を用
いた。そして試験終了後、バルブシートの自り面幅増加
量と相手パルプの摩耗量を測定した。この試験結果を、
焼結体の硬さ及び密度と共に下の表に記す。なお表には
後述する実施例２〜５および比較例１〜２の結果も併せ
載せた。Thereafter, the sintered body obtained as described above was processed into a valve seat, and the valve seat was press-fitted and assembled as an exhaust valve seat into the aluminum alloy cylinder head of a 4-cylinder engine with a displacement of 2000 cc, and a bench durability test was performed. The bench durability test was conducted using leaded gasoline, 660ar, p,
m, continued for 200 hours at full load. The mating pulp at this time was a general-purpose pulp (JISSUH5) without KFi overlay. After the test was completed, the amount of increase in the self-face width of the valve seat and the amount of wear of the mating pulp were measured. This test result,
The hardness and density of the sintered body are listed in the table below. The table also includes the results of Examples 2 to 5 and Comparative Examples 1 to 2, which will be described later.

実施例２〜５ 表のごとく組成を変えて実施例１と同様の方法でバルブ
シートを製作し、これを実施例１と同様の台上耐久試験
に供した。なお実施例２．４については、焼結体をｐｂ
塊に接触させアンモニア分解ガス雰囲気中で１０５０℃
×３０分間加熱してｐｂを含浸させた。また表記以外に
ステアリン酸亜鉛をα８チ含むことは実施例１と同様で
ある。Examples 2 to 5 Valve seats were manufactured in the same manner as in Example 1 with different compositions as shown in the table, and were subjected to the same bench durability test as in Example 1. Regarding Example 2.4, the sintered body was
Contact with lumps and heat at 1050℃ in ammonia decomposition gas atmosphere
× It was heated for 30 minutes to impregnate PB. In addition, it is the same as in Example 1 that α8 zinc stearate is included in addition to the description.

比較例１゜ 鋳鉄ＦＣｓａを用−て実施例２と同様の方法でバルブシ
ートを製作し、実施例１と同様の台上耐久試験に供した
。Comparative Example 1 A valve seat was manufactured using cast iron FCsa in the same manner as in Example 2, and subjected to the same bench durability test as in Example 1.

比較例２゜ ＪＩＳ耐熱鋼材５ＵＨ４Ｂを用い、実施例２と同様の方
法でバルブシートを製作し、実施例１と同様の台上耐久
試験に供した。Comparative Example 2 A valve seat was manufactured using JIS heat-resistant steel 5UH4B in the same manner as in Example 2, and subjected to the same bench durability test as in Example 1.

、上記の表よ）本発明の範囲に包含される実施例１〜５
のものは、ｈずれもパルプ摩耗量、バルブシート当り面
幅共小さく、自身の耐摩耗性の優れていること、および
相手部材に対する攻撃性の小さいことが明らかである。, above table) Examples 1 to 5 falling within the scope of the present invention
It is clear that the h deviation, pulp abrasion amount, and valve seat contact surface width are small, and that the material itself has excellent wear resistance and is less aggressive to the mating member.

特罠軛施例２及び４は、硬質粒子の組成または配合量に
よって、千れ自体の硬さが著しく高められているにも拘
らず、ｐｂ含浸の効果によりバルブの摩耗量が他の実施
例と同程度を維持している。In Examples 2 and 4, the hardness of the particles themselves is significantly increased due to the composition or amount of hard particles, but the amount of valve wear is lower than that of other examples due to the effect of PB impregnation. remains at the same level.

これに対して比較例１及び２け自身の耐摩耗性が低いう
えにバルブの摩耗量が大きい。On the other hand, the wear resistance of Comparative Examples 1 and 2 is low, and the amount of wear of the valve is large.

、〔発明の効果〕 以上、詳細に説明したように１本発明にか＼るバルブシ
ート用鉄系焼結合金は、Ｃを含むＦｅ基地中に＃摩耗性
に富む硬質合金粒子を分散させ、かつ所望に応じてｐｂ
を含浸させることにより、自身の耐摩耗性が向上するば
かシか、相手部材に対する攻撃性を弱めて、該部材の摩
耗量を減少する効果を奏し、これによって盛会等の耐摩
耗処理を施してないエンジンパルプの安定的使用が可能
となる。, [Effects of the Invention] As explained in detail above, the iron-based sintered alloy for valve seats according to the present invention has hard alloy particles with high abrasion properties dispersed in an Fe base containing C, and pb as desired
By impregnating the material, it not only improves its own wear resistance, but also weakens its aggressiveness towards the other member and reduces the amount of wear on the member. This makes it possible to stably use engine pulp that is not available in the market.

（ほか１名）(1 other person)

Claims (2)

【特許請求の範囲】[Claims] （１）パーライトを主体とする鉄（Ｆｅ）基地中に、重
量比で炭素（Ｃ）０．５〜２．０％、ニッケル（Ｎｉ）
５〜３０％、モリブデン（Ｍｏ）５〜１５％、クロム（
Ｃｒ）１０〜４０％、残部コバルト（Ｃｏ）からなる硬
質粒子を重量比として５ないし３０％分散させ、全体の
組成を；Ｃｏ０．６５〜２．３％、Ｃｒ０．５〜１２％
、Ｍｏ０．２５〜４．５％、Ｎｉ０．２５〜９％、Ｃ１
．０〜２．８％、残部Ｆｅ及び不可避不純物としたこと
を特徴とするバルブシート用鉄系焼結合金。(1) 0.5 to 2.0% carbon (C) and nickel (Ni) by weight in an iron (Fe) base mainly composed of pearlite.
5-30%, molybdenum (Mo) 5-15%, chromium (
Hard particles consisting of 10 to 40% Cr) and 5 to 30% by weight of cobalt (Co) are dispersed, and the overall composition is: 0.65 to 2.3% Co, 0.5 to 12% Cr.
, Mo0.25-4.5%, Ni0.25-9%, C1
．． An iron-based sintered alloy for a valve seat, characterized in that the balance is Fe and unavoidable impurities in an amount of 0 to 2.8%. （２）パーライトを主体とする鉄（Ｆｅ）基地中に、重
量比で炭素（Ｃ）０．５〜２．０％、ニッケル（Ｎｉ）
５〜３０％、モリブデン（Ｍｏ）５〜１５％、クロム（
Ｃｒ）１０〜４０％、残部コバルト（Ｃｏ）からなる硬
質粒子を重量比として５ないし３０％分散させ、全体の
組成を；Ｃｏ０．６５〜２．３％、Ｃｒ０．５〜１２％
、Ｍｏ０．２５〜４．５％、Ｎｉ０．２５〜９％、Ｃ１
．０〜２．８％、残部Ｆｅ及び不可避不純物とした焼結
合金に全重量比にして１ないし２０％の鉛（Ｐｂ）を含
浸したことを特徴とするバルブシート用鉄系焼結合金。(2) 0.5 to 2.0% carbon (C) and nickel (Ni) by weight in an iron (Fe) base mainly composed of pearlite.
5-30%, molybdenum (Mo) 5-15%, chromium (
Hard particles consisting of 10 to 40% Cr) and 5 to 30% by weight of cobalt (Co) are dispersed, and the overall composition is; 0.65 to 2.3% Co, 0.5 to 12% Cr.
, Mo0.25-4.5%, Ni0.25-9%, C1
．． An iron-based sintered alloy for a valve seat, characterized in that the sintered alloy is impregnated with 1 to 20% lead (Pb) in a total weight ratio of 0 to 2.8%, the balance being Fe and unavoidable impurities.