JP3942136B2 - Iron-based sintered alloy - Google Patents

Iron-based sintered alloy Download PDF

Info

Publication number
JP3942136B2
JP3942136B2 JP2000022160A JP2000022160A JP3942136B2 JP 3942136 B2 JP3942136 B2 JP 3942136B2 JP 2000022160 A JP2000022160 A JP 2000022160A JP 2000022160 A JP2000022160 A JP 2000022160A JP 3942136 B2 JP3942136 B2 JP 3942136B2
Authority
JP
Japan
Prior art keywords
weight
caf
iron
powder
sintered alloy
Prior art date
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.)
Expired - Fee Related
Application number
JP2000022160A
Other languages
Japanese (ja)
Other versions
JP2001214245A (en
Inventor
欣也 川瀬
賢治 織戸
義成 石井
耕一郎 森本
Original Assignee
三菱マテリアルPmg株式会社
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by 三菱マテリアルPmg株式会社 filed Critical 三菱マテリアルPmg株式会社
Priority to JP2000022160A priority Critical patent/JP3942136B2/en
Publication of JP2001214245A publication Critical patent/JP2001214245A/en
Application granted granted Critical
Publication of JP3942136B2 publication Critical patent/JP3942136B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Images

Description

【0001】
【発明の属する技術分野】
この発明は、自己潤滑性、切削性、耐焼付き性および強度を有すると共に耐摩耗性に優れかつ相手攻撃性が少ない鉄基焼結合金に関するものであり、この鉄基焼結合金は、バルブシート、バルブガイド、ピストン耐摩環などエンジンの耐摩耗部品の製造に使用される。
【0002】
【従来の技術】
焼結技術が進歩し、鉄基焼結合金からなる各種機械部品を精度良く量産できるようになり、エンジンの耐摩耗部品も鉄基焼結合金により製造するようになってきた。
一方、近年、天然ガスをはじめとする気体燃料を使用するエンジン、あるいは燃料を燃焼室内に直接噴射する直噴射エンジンが開発されている。これら新型エンジンでは吸気側バルブからは気体だけを供給し、従来エンジンのようにガソリンと空気の混合ガスを供給するものではないところから、吸気側バルブ部分でのガソリンによる潤滑作用が全く無く、したがって吸気側バルブシートおよびバルブガイドは吸気側バルブを激しく摩耗するという欠点があった。
また従来エンジンでは燃焼室内で発生した微量の煤など燃焼生成物が排気側バルブガイドおよびバルブシートに潤滑性を付与していたが、気体燃料を使用する新型エンジンの場合、燃焼生成物の生成が極めて少く、そのために排気側バルブガイドおよびバルブシートは排気側バルブを激しく摩耗するという欠点があった。
これを解決するために鉄基焼結合金に固体潤滑剤としてCaF2を添加して自己潤滑性を高めることにより、激しい摩耗を防止しようとしている。例えば、CaF2を含む鉄基焼結合金の一例として、重量%で、C:0.7〜1.6%、Si:0.1〜1%、Mn:0.05〜1%,Cr:1〜8%,Mo:1〜10%,V:0.1〜2%,Co:1〜20%を含み、残部Feおよび不可避不純物からなり、硬質粒子が粒径10〜150μmのCr−Mo−Si−Co系金属間化合物粒子、Fe−Mo粒子およびFe−Si−Mo系金属間化合物粒子の内の1種または2種以上を合計で5〜25重量%を素地中に分散させ、さらに粒径1〜50μmのCaF2を分散させた鉄基焼結合金が知られており、この鉄基焼結合金はバルブシートなど摺動部材の素材として使用されるとしている(特開平11−21659号公報参照)。
【0003】
【発明が解決しようとする課題】
しかし、前記従来のCaF2を含有する鉄基焼結合金からなるバルブシートは十分な強度および耐摩耗性が得られず、また自己潤滑性に劣るために相手攻撃性が大きいという欠点があった。
【0004】
【課題を解決するための手段】
そこで、本発明者らは、上述のような観点から、優れた強度および耐摩耗性を有すると共に自己潤滑性に優れかつ相手攻撃性が少ない鉄基焼結合金を得るべく研究を行っていたところ、
(a)Cu粉末、CaF2粉末およびFe粉末からなる組成の混合粉末を成形したのちCu液相による液相焼結を行うことにより得られたCu:8〜40重量%、CaF2:0.5〜10重量%を含有し、残りがFeおよび不可避不純物からなる組成の鉄基焼結合金は、図1に示されるように、CaF2粒子1が素地の気孔2の内部に存在した組織が形成され、かかる組成および組織を有する鉄基焼結合金は優れた強度および耐摩耗性を有すると共に自己潤滑性に優れかつ相手攻撃性が少ない、
(b)Cu粉末、CaF2粉末、Ni粉末およびC粉末の内の1種または2種、並びにFe粉末からなる組成の混合粉末を成形したのちCu液相による液相焼結を行うことにより得られたCu:8〜40重量%、CaF2:0.5〜10重量%を含有し、さらにNi:0.5〜10重量%、C:0.05〜3重量%の内の1種または2種を含有し、残りがFeおよび不可避不純物からなる組成を有する鉄基焼結合金は、図1に示されるように、CaF2粒子1が素地の気孔2の内部に存在した組織が形成され、かかる組成および組織を有する鉄基焼結合金は優れた強度および耐摩耗性を有すると共に自己潤滑性に優れかつ相手攻撃性が少ない、という知見を得たのである。
【0005】
この発明は、かかる知見にもとづいて成されたものであって、
(1)Cu:8〜40重量%、CaF2:0.5〜10重量%を含有し、残りがFeおよび不可避不純物からなる組成を有し、かつ前記CaF2は素地の気孔内部に存在して分散している組織を有する鉄基焼結合金、
(2)Cu:8〜40重量%、CaF2:0.5〜10重量%、Ni:0.5〜10重量%を含有し、残りがFeおよび不可避不純物からなる組成を有し、かつ前記CaF2は素地の気孔内部に存在して分散している組織を有する鉄基焼結合金、
(3)Cu:8〜40重量%、CaF2:0.5〜10重量%、C:0.05〜3重量%を含有し、残りがFeおよび不可避不純物からなる組成を有し、かつ前記CaF2は素地の気孔内部に存在して分散している組織を有する鉄基焼結合金、
(4)Cu:8〜40重量%、CaF2:0.5〜10重量%、Ni:0.5〜10重量%、C:0.05〜3重量%を含有し、残りがFeおよび不可避不純物からなる組成を有し、かつ前記CaF2は素地の気孔内部に存在して分散している組織を有する鉄基焼結合金、に特徴を有するものである。
【0006】
この発明の鉄基焼結合金が優れた強度を有すると共に自己潤滑性および耐摩耗性に優れかつ相手攻撃性が少ない理由として下記の理由が考えられる。すなわち、従来の鉄基焼結合金は、図2(a)の組織説明図に示されるように、固体潤滑剤として角張ったCaF2粒子1が素地3中に埋め込まれた状態で分散した組織を有しており、かかる組織を有する鉄基焼結合金が摩耗すると、図2(b)の組織説明図に示されるように、角張ったCaF2粒子1が脱落してその部分に鋭角部分4を有する空孔6が形成され、この鉄基焼結合金に荷重が付加されると、CaF2粒子が脱落して形成された空孔6の鋭角部分4から亀裂5が発生し、そのために亀裂周囲の破壊や摩耗の進行が生じる。
ところが、この発明の鉄基焼結合金は、図1(a)に示されるように、鋭角部分4を有するCaF2粒子1は素地の気孔2の内部に付着した状態で存在する組織が形成され、かかる鉄基焼結合金の素地3に形成されている気孔2はほぼ球形であるために、摩耗中にCaF2粒子1が気孔2から脱落しても気孔2は球形のまま残り、荷重が付加されても亀裂は気孔2から発生し難く、そのために局所的な破壊や摩耗の進行が防止されるものと考えられる。さらに、気孔2に付着したCaF2粒子1は素地3中に埋め込まれたものより脱落しやすく効率的に潤滑剤の役目を果たすために自己潤滑性に優れかつ相手攻撃性も少なくなるものと考えられる。
【0007】
また、本発明者らは、
(c)前記(a)または(b)記載の混合粉末に、さらにマイクロビッカース硬さ(以下、MHVという):500〜2000の硬質粉末を0.5〜20重量%添加した混合粉末を成形したのち、Cu液相による液相焼結を行うことにより、Cu:8〜40重量%、CaF2:0.5〜10重量%を含有し、さらにNi:0.5〜10重量%、C:0.05〜3重量%の内の1種または2種を含有し、さらにCr,Mn,Mo,W,V,Si,Co,Nbのうち1種または2種以上を合計で0.5〜20重量%を含有し、残りがFeおよび不可避不純物からなる組成を有する鉄基焼結合金は耐摩耗性が一層向上する、
(d)前記Cr,Mn,Mo,W,V,Si,Co,Nbのうち1種または2種以上の成分は、素地の固溶させても良く、またはMHV:500〜2000の硬質粒子相として素地中に均一分散させても良く、この硬質粒子相が分散した素地中の気孔の内部にCaF2粒子が存在し分散している組織を有する鉄基焼結合金は、素地中に硬質粒子が均一分散しているために耐摩耗性が一層向上する、
という知見を得たのである。
【0008】
この発明は、かかる知見に基づいて成されたものであって、
前記Cr,Mn,Mo,W,V,Si,Co,Nbのうち1種または2種以上の成分を素地に固溶させたこの発明は、
(5)Cu:8〜40重量%、CaF2:0.5〜10重量%、Ni:0.5〜10重量%を含有し、さらにCr,Mn,Mo,W,V,Si,Co,Nbのうち1種または2種以上を合計で0.5〜20重量%を含有し、残りがFeおよび不可避不純物からなる組成を有し、かつ前記CaF2は素地の気孔内部に存在して分散している組織を有する鉄基焼結合金、
(6)Cu:8〜40重量%、CaF2:0.5〜10重量%、Ni:0.5〜10重量%、C:0.05〜3重量%を含有し、さらにCr,Mn,Mo,W,V,Si,Co,Nbのうち1種または2種以上を合計で0.5〜20重量%を含有し、残りがFeおよび不可避不純物からなる組成を有し、かつ前記CaF2は素地の気孔内部に存在して分散している組織を有する鉄基焼結合金、に特徴を有するものである。
【0009】
前記(1)〜(6)記載の鉄基焼結合金は、Fe粉末、Cu粉末、CaF2粉末を必須の原料粉末として混合し、さらに必要に応じてNi粉末、C粉末およびMHV:500〜2000の硬質粉末を混合して得られた混合粉末を、成形したのちCu液相による液相焼結することにより製造することができる。
【0010】
この発明の鉄基焼結合金は、一層具体的には、原料粉末として、Fe粉末、Cu粉末、CaF2粉末、黒鉛粉末、Ni粉末およびMHV:500〜2000の硬質粉末およびMHV:500〜2000の硬質粉末を用意し、これら原料粉末を所定の割合で配合し混合し、さらに金型成形時の潤滑剤であるステアリン酸亜鉛粉末とともにダブルコーンミキサーで混合し、プレス成形して圧粉体を作製し、圧粉体を水素を含む窒素雰囲気中、温度:1100〜1300℃(一層好ましくは、1090〜1200℃)で焼結し、Cu液相による液相焼結することにより製造する。このようにしてCu液相による液相焼結を行なうと、CaF2の周囲のCu液相は、CaF2から離れるように流動し、CaF2の周囲は気孔となり、結果としてCaF2が気孔内部に押し出された組織となるものと考えられる。
また、気孔内部に存在するCaF2は、素地の気孔内の合金と緩く結合しているために脱落しやすく、脱落したCaF2は摩耗面に散乱して固体潤滑剤として効率的に作用することにより自己潤滑性を向上させる。
【0011】
つぎに、この発明の鉄基燒結合金の成分組成を上記のごとく限定した理由について説明する。
【0012】
(a)Cu
Cuは、耐摩耗性、放熱性、切削性および耐焼付き性を向上させ、さらに相手攻撃性を減少させる効果があるが、その含有量が8重量%未満ではその効果が十分でなく、一方、40重量%を越えると液相が過大となり、焼結中に変形が生じて寸法のバラツキが大きくなるので好ましくない。したがって、Cuの含有量は8〜40重量%に定めた。Cuの含有量の一層好ましい範囲は9〜25重量%である。
【0013】
(b)CaF2
CaF2は、自己潤滑性、切削性、耐焼付き性および耐摩耗性の向上に効果があるので添加するが、0.5重量%未満ではその効果が十分でなく、一方、10重量%を越えて添加すると焼結中に変形が生じて寸法のバラツキが大きくなるので好ましくない。したがって、CaF2の含有量は0.5〜10重量%に定めた。CaF2の含有量の一層好ましい範囲は1〜7重量%である。
【0014】
(c)Ni
NiはFe基合金相とCu基合金相の密着性を向上させることにより、強度と耐摩耗性を向上させるので必要に応じて含有させるが、その量が0.5重量%未満では効果が現れず、一方、10重量%を越えて含有させてもも効果が少なく経済的に好ましくない。したがって、Niの含有量は0.5〜10重量%に定めた。Ni含有量の一層好ましい範囲は1〜8重量%である。
【0015】
(d)C
Cは、強度と耐摩耗性を向上させるので必要に応じて添加するが、その量が0.05重量%未満では効果が現れず、一方、3重量%を越えて含有させると、靭性および寸法安定性が低下するので好ましくない。したがって、Cの含有量は0.05〜3重量%に定めた。C含有量の一層好ましい範囲は0.1〜2重量%である。
【0016】
(e)Cr,Mn,Mo,W,V,Si,Co,Nb
これら成分は、耐摩耗性および強度を向上させるために必要に応じて含有させるが、これら成分の1種または2種以上を合計で0.5重量%未満含有させても所望の効果が現れず、一方、20重量%を越えて含有させると、靭性が低下するので好ましくない。したがって、これら成分の1種または2種以上を合計で0.5〜20重量%に定めた。一層好ましい範囲は1〜10重量%である。
また、これら成分は硬質合金粉末として添加し、素地に分散させて硬質粒子相を形成させることができるが、硬質粒子相を形成させる場合は1〜15重量%の範囲内とすることが好ましい。この場合の一層好ましい範囲は4〜10重量%である。そして素地に分散する硬質粒子相は、平均粒径:10〜100μm、MHV:500〜2000の範囲内の硬質粒子相を面積率:1〜30%で分散させることが好ましく、その理由は、MHVが500未満の硬質合金粒子相では十分な耐摩耗性が得られないので硬質合金粒子相を形成させる意味が無くなく、一方、MHVが2000を越えるとバルブを過大に摩耗させるので好ましくないことによるものである。また、鉄基燒結合金素地中に面積率で1%分散していても十分な耐摩耗性が得られず、一方、30%を越えて分散すると硬質粒子相が多過て靭性が不足するので好ましくないからである。硬質合金粒子相の分散量の一層好ましい範囲は面積率で8〜25%である。
【0017】
【発明の実施の形態】
実施例1
原料粉末として、平均粒径:55μmのFe粉末、平均粒径:11μmのCu粉末、平均粒径:10μmのNi粉末、平均粒径:18μmの黒鉛粉末および平均粒径:20μmのCaF2粉末を用意した。さらに下記の表1に示される成分組成を有する硬質合金粉末A〜Cを用意した。
【0018】
【表1】
【0019】
前記用意したFe粉末、Cu粉末、CaF2粉末、Ni粉末、黒鉛粉末、および表1の硬質合金粉末A〜Cを表2〜3に示される割合で配合し混合して原料混合粉末を作製し、この原料混合粉末にさらに金型成形時の潤滑剤であるステアリン酸亜鉛粉末を外掛けで0.8重量%に当たる量だけ添加して混合し、プレス成形して圧粉体を作製した。この圧粉体をN2−5%H2の混合雰囲気中、温度:1140℃、20分保持の条件で焼結し、表4〜5に示される成分組成を有する本発明鉄基燒結合金(以下、本発明合金という)1〜17を作製した。
【0020】
一方、前記特開平11−21659号公報記載の、重量%で、C:1.0、Si:0.26%、Mn:0.13%,Cr:3.14%,Mo:3.37%,V:0.25%,Co:6.0%およびCaF2:5%を含み、さらに、粒径:10μmのCr−Mo−Si−Co金属間化合物:10%を20面積%となるように含み、残部Feおよび不可避不純物からなる従来鉄基焼結合金(以下、従来合金という)を用意した。
【0021】
前記本発明合金1〜17および従来合金について下記の摩耗試験を行った。
【0022】
SUH36の材質からなり外径が30mmの傘部分を有するバルブを用意し、このバルブの傘部分を温度:900℃に保持し、さらに本発明合金1〜17および従来合金からなるバルブシートを作製し、これらバルブシートをそれぞれ内部が水冷されている治具に圧入し、天然ガス燃焼雰囲気中で着座荷重:30kg、バルブ着座回数:3000回/分の条件で150時間試験し、バルブシートおよびバルブの最大摩耗量を測定し、その結果を表4〜5に示した。
【0023】
【表2】
【0024】
【表3】
【0025】
【表4】
【0026】
【表5】
【0027】
表4〜表5に示される結果から、本発明合金1〜17で作製したバルブシートは従来合金で作製したバルブシートに比べて、バルブシートの最大摩耗量が少ないところから、本発明合金1〜17は従来合金に比べて優れた耐摩耗性を有し、さらに本発明合金1〜17は従来合金に比べて相手材であるバルブの最大摩耗量が少ないところから相手攻撃性が少ないことが分かる。
【0028】
【発明の効果】
上述のように、この発明の鉄基燒結合金は、従来以上の耐摩耗性を有し、また相手材であるバルブに対する相手攻撃性が少ないところから、エンジンなどの自動車産業の発展に大いに貢献し得るものである。
【図面の簡単な説明】
【図1】 この発明の鉄基燒結合金の組織を説明するための説明図である。
【図2】 従来の鉄基燒結合金の組織を説明するための説明図である。
【符号の説明】
1 CaF2粒子
2 気孔
3 素地
4 鋭角部分
5 亀裂
6 CaF2が脱落してできた空孔
[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an iron-based sintered alloy that has self-lubricating properties, machinability, seizure resistance, strength, and excellent wear resistance and less counterattack properties. Used for manufacturing wear-resistant parts of engines such as valve guides and piston wear-resistant rings.
[0002]
[Prior art]
Advances in sintering technology have made it possible to mass-produce various machine parts made of iron-based sintered alloys with high accuracy, and to produce wear-resistant parts for engines using iron-based sintered alloys.
On the other hand, in recent years, an engine that uses a gaseous fuel such as natural gas or a direct injection engine that directly injects fuel into a combustion chamber has been developed. Since these new engines supply only gas from the intake side valve and do not supply a mixed gas of gasoline and air unlike the conventional engine, there is no lubrication effect by gasoline at the intake side valve part, therefore The intake side valve seat and the valve guide have the drawback of severely wearing the intake side valve.
In conventional engines, combustion products such as small amounts of soot generated in the combustion chamber have given lubricity to the exhaust valve guide and valve seat. However, in the case of new engines using gaseous fuel, combustion products are not produced. Therefore, the exhaust side valve guide and the valve seat have a drawback in that the exhaust side valve is severely worn.
In order to solve this, an attempt is made to prevent severe wear by adding CaF 2 as a solid lubricant to the iron-based sintered alloy to enhance self-lubricity. For example, as an example of an iron-based sintered alloy containing CaF 2 , C: 0.7 to 1.6%, Si: 0.1 to 1%, Mn: 0.05 to 1%, Cr: Cr—Mo containing 1 to 8%, Mo: 1 to 10%, V: 0.1 to 2%, Co: 1 to 20%, the balance being Fe and inevitable impurities, and hard particles having a particle size of 10 to 150 μm -Disperse 5 to 25% by weight of one or more of Si-Co intermetallic compound particles, Fe-Mo particles and Fe-Si-Mo intermetallic compound particles in the base material; An iron-based sintered alloy in which CaF 2 having a particle size of 1 to 50 μm is dispersed is known, and this iron-based sintered alloy is used as a material for a sliding member such as a valve seat (Japanese Patent Laid-Open No. 11-21659). No. publication).
[0003]
[Problems to be solved by the invention]
However, the conventional valve seat made of an iron-based sintered alloy containing CaF 2 has a drawback that sufficient strength and wear resistance cannot be obtained, and the self-lubricating property is inferior, so that the opponent attack is large. .
[0004]
[Means for Solving the Problems]
In view of the above, the present inventors have been researching to obtain an iron-based sintered alloy having excellent strength and wear resistance, excellent self-lubricating properties, and less counterattack properties. ,
(A) Cu powder was obtained by performing the liquid-phase sintering of Cu liquid phase After molding a mixed powder having a composition consisting of CaF 2 powder and Fe powder Cu: 8 to 40 wt%, CaF 2: 0. As shown in FIG. 1, the iron-based sintered alloy containing 5 to 10% by weight and the remainder composed of Fe and inevitable impurities has a structure in which CaF 2 particles 1 exist inside the pores 2 of the substrate. The formed iron-based sintered alloy having such a composition and structure has excellent strength and wear resistance, and is excellent in self-lubricating properties and has less opponent attack,
(B) obtained by molding liquid powder sintering of Cu powder, CaF 2 powder, Ni powder or C powder, and mixed powder having a composition comprising Fe powder and then performing liquid phase sintering with Cu liquid phase. Cu: 8 to 40% by weight, CaF 2 : 0.5 to 10% by weight, Ni: 0.5 to 10% by weight, C: 0.05 to 3% by weight or As shown in FIG. 1, the iron-based sintered alloy containing two types and the remainder composed of Fe and inevitable impurities has a structure in which CaF 2 particles 1 exist inside the pores 2 of the substrate. The inventors have found that an iron-based sintered alloy having such a composition and structure has excellent strength and wear resistance, is excellent in self-lubricating properties, and has little opponent attack.
[0005]
This invention was made based on such knowledge,
(1) Cu: 8 to 40% by weight, CaF 2 : 0.5 to 10% by weight, with the remainder composed of Fe and inevitable impurities, and the CaF 2 is present in the pores of the substrate An iron-based sintered alloy having a dispersed structure,
(2) Cu: 8 to 40% by weight, CaF 2 : 0.5 to 10% by weight, Ni: 0.5 to 10% by weight, with the remainder consisting of Fe and inevitable impurities, and CaF 2 is an iron-based sintered alloy having a structure that exists and is dispersed inside the pores of the substrate,
(3) Cu: 8 to 40% by weight, CaF 2 : 0.5 to 10% by weight, C: 0.05 to 3% by weight, with the remainder consisting of Fe and inevitable impurities, and CaF 2 is an iron-based sintered alloy having a structure that exists and is dispersed inside the pores of the substrate,
(4) Cu: 8 to 40% by weight, CaF 2 : 0.5 to 10% by weight, Ni: 0.5 to 10% by weight, C: 0.05 to 3% by weight, the remainder being Fe and inevitable It is characterized by an iron-based sintered alloy having a composition composed of impurities and having a structure in which CaF 2 is present and dispersed inside the pores of the substrate.
[0006]
The following reason can be considered as the reason why the iron-based sintered alloy of the present invention has excellent strength, is excellent in self-lubricating property and wear resistance, and has less opponent attack. That is, the conventional iron-based sintered alloy has a structure in which angular CaF 2 particles 1 as a solid lubricant are dispersed in a state where they are embedded in the substrate 3 as shown in the structure explanatory diagram of FIG. When the iron-based sintered alloy having such a structure is worn, as shown in the explanatory diagram of FIG. 2 (b), the angular CaF 2 particles 1 drop off, and the acute angle part 4 is formed in the part. When a hole 6 is formed and a load is applied to the iron-based sintered alloy, a crack 5 is generated from the acute angle portion 4 of the hole 6 formed by the drop of CaF 2 particles. Destruction and progress of wear occur.
However, in the iron-based sintered alloy of the present invention, as shown in FIG. 1A, a CaF2 particle 1 having an acute angle portion 4 is formed with a structure that exists in a state of adhering inside the pores 2 of the substrate, Since the pores 2 formed in the iron-based sintered alloy substrate 3 are substantially spherical, even if the CaF 2 particles 1 fall out of the pores 2 during wear, the pores 2 remain spherical and load is applied. Even if this is done, cracks are unlikely to occur from the pores 2, and therefore, it is considered that local breakage and wear progress are prevented. Further, the CaF 2 particles 1 adhering to the pores 2 are more likely to fall off than those embedded in the substrate 3 and effectively perform the role of a lubricant. It is done.
[0007]
In addition, the inventors
(C) A mixed powder obtained by adding 0.5 to 20% by weight of a hard powder of micro Vickers hardness (hereinafter referred to as MHV): 500 to 2000 to the mixed powder described in (a) or (b) was molded. After that, by performing liquid phase sintering with a Cu liquid phase, Cu: 8 to 40% by weight, CaF 2 : 0.5 to 10% by weight, Ni: 0.5 to 10% by weight, C: 0.05 to 3% by weight of one or two of Cr, Mn, Mo, W, V, Si, Co, and Nb, or a total of 0.5 to 0.5%. An iron-based sintered alloy having a composition containing 20% by weight and the balance consisting of Fe and inevitable impurities further improves wear resistance.
(D) One or more components of Cr, Mn, Mo, W, V, Si, Co, and Nb may be dissolved in the substrate, or a hard particle phase of MHV: 500 to 2000 The iron-based sintered alloy having a structure in which CaF 2 particles are present and dispersed inside the pores in which the hard particle phase is dispersed may be dispersed uniformly in the substrate. Wear resistance is further improved due to uniform dispersion.
I got this knowledge.
[0008]
This invention is made based on such knowledge,
The present invention in which one or more components of Cr, Mn, Mo, W, V, Si, Co, and Nb are dissolved in the substrate,
(5) Cu: 8~40 wt%, CaF 2: 0.5 to 10 wt%, Ni: contained 0.5 to 10 wt%, further Cr, Mn, Mo, W, V, Si, Co, One or more of Nb contains a total of 0.5 to 20% by weight, and the balance is composed of Fe and inevitable impurities, and the CaF 2 is dispersed inside the pores of the substrate. An iron-based sintered alloy having a texture
(6) Cu: 8~40 wt%, CaF 2: 0.5 to 10 wt%, Ni: 0.5 to 10 wt%, C: 0.05 to 3 containing wt%, further Cr, Mn, One or two or more of Mo, W, V, Si, Co, and Nb are contained in a total amount of 0.5 to 20% by weight, with the balance being composed of Fe and inevitable impurities, and the CaF 2 Is characterized by an iron-based sintered alloy having a dispersed structure existing inside the pores of the substrate.
[0009]
In the iron-based sintered alloy described in (1) to (6), Fe powder, Cu powder, and CaF 2 powder are mixed as essential raw material powders, and Ni powder, C powder, and MHV: 500 to 500 as necessary. It can be manufactured by forming a mixed powder obtained by mixing 2000 hard powders and then liquid phase sintering with a Cu liquid phase.
[0010]
More specifically, the iron-based sintered alloy of the present invention includes Fe powder, Cu powder, CaF 2 powder, graphite powder, Ni powder, hard powder of MHV: 500 to 2000, and MHV: 500 to 2000 as raw material powder. These raw material powders are blended and mixed at a predetermined ratio, mixed with a zinc stearate powder as a lubricant at the time of molding with a double cone mixer, and pressed to form a green compact. The green compact is manufactured by sintering at a temperature of 1100 to 1300 ° C. (more preferably 1090 to 1200 ° C.) in a nitrogen atmosphere containing hydrogen and liquid phase sintering with a Cu liquid phase. In this manner, when performing liquid-phase sintering of Cu liquid phase, Cu liquid around the CaF 2 is to flow away from the CaF 2, the periphery of the CaF 2 becomes pores, resulting in an internal CaF 2 pores It is thought that it will be an organization pushed out by
In addition, CaF 2 existing inside the pores is loosely bonded with the alloy in the pores of the base material, so it is easy to fall off, and the dropped CaF 2 is scattered on the wear surface and acts effectively as a solid lubricant. Improves self-lubricity.
[0011]
Next, the reason why the component composition of the iron-base bond gold according to the present invention is limited as described above will be described.
[0012]
(A) Cu
Cu has the effect of improving wear resistance, heat dissipation, machinability, and seizure resistance, and further reducing the opponent attack, but if its content is less than 8% by weight, the effect is not sufficient, If it exceeds 40% by weight, the liquid phase becomes excessive, deformation occurs during sintering, and the dimensional variation increases, which is not preferable. Therefore, the Cu content is set to 8 to 40% by weight. A more preferable range of the Cu content is 9 to 25% by weight.
[0013]
(B) CaF 2
CaF 2 is added because it is effective in improving self-lubricity, machinability, seizure resistance, and wear resistance. However, if it is less than 0.5% by weight, the effect is not sufficient, whereas it exceeds 10% by weight. If added in this manner, deformation occurs during sintering, resulting in a large dimensional variation. Therefore, the content of CaF 2 is set to 0.5 to 10% by weight. A more preferable range of the content of CaF 2 is 1 to 7% by weight.
[0014]
(C) Ni
Ni improves the strength and wear resistance by improving the adhesion between the Fe-based alloy phase and the Cu-based alloy phase, so it is contained as needed. However, if the amount is less than 0.5% by weight, the effect appears. On the other hand, even if the content exceeds 10% by weight, the effect is small and economically undesirable. Therefore, the Ni content is set to 0.5 to 10% by weight. A more preferable range of the Ni content is 1 to 8% by weight.
[0015]
(D) C
C improves strength and abrasion resistance, and is added as necessary. However, if its amount is less than 0.05% by weight, no effect appears, while if it exceeds 3% by weight, toughness and dimensions are added. Since stability falls, it is not preferable. Therefore, the content of C is set to 0.05 to 3% by weight. A more preferable range of the C content is 0.1 to 2% by weight.
[0016]
(E) Cr, Mn, Mo, W, V, Si, Co, Nb
These components are contained as necessary in order to improve the wear resistance and strength. However, even if one or more of these components are contained in a total amount of less than 0.5% by weight, the desired effect does not appear. On the other hand, if the content exceeds 20% by weight, the toughness decreases, which is not preferable. Accordingly, one or more of these components are set to 0.5 to 20% by weight in total. A more preferred range is 1 to 10% by weight.
These components can be added as a hard alloy powder and dispersed in the substrate to form a hard particle phase. However, when a hard particle phase is formed, it is preferably in the range of 1 to 15% by weight. A more preferable range in this case is 4 to 10% by weight. The hard particle phase dispersed in the substrate preferably has an average particle size of 10 to 100 μm and a hard particle phase in the range of MHV: 500 to 2000 is preferably dispersed at an area ratio of 1 to 30%. When the hard alloy particle phase is less than 500, sufficient wear resistance cannot be obtained, so there is no point in forming the hard alloy particle phase. On the other hand, if the MHV exceeds 2000, the valve is excessively worn, which is not preferable. Is. Further, even if 1% by area ratio is dispersed in the iron-base bonded metal base, sufficient wear resistance cannot be obtained. On the other hand, if it exceeds 30%, the hard particle phase is excessive and the toughness is insufficient. It is because it is not preferable. A more preferable range of the dispersion amount of the hard alloy particle phase is 8 to 25% in terms of area ratio.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Example 1
As raw material powder, Fe powder having an average particle diameter of 55 μm, Cu powder having an average particle diameter of 11 μm, Ni powder having an average particle diameter of 10 μm, graphite powder having an average particle diameter of 18 μm, and CaF 2 powder having an average particle diameter of 20 μm. Prepared. Furthermore, hard alloy powders A to C having the component compositions shown in Table 1 below were prepared.
[0018]
[Table 1]
[0019]
The prepared Fe powder, Cu powder, CaF 2 powder, Ni powder, graphite powder, and hard alloy powders A to C shown in Table 1 are mixed and mixed at the ratios shown in Tables 2 to 3 to prepare a raw material mixed powder. The raw material mixed powder was further mixed with zinc stearate powder, which is a lubricant used in molding the die, in an amount corresponding to 0.8% by weight, and pressed to prepare a green compact. This green compact was sintered in a mixed atmosphere of N 2 -5% H 2 at a temperature of 1140 ° C. and held for 20 minutes, and the iron-based binder of the present invention having the component composition shown in Tables 4 to 5 ( (Hereinafter referred to as alloys of the present invention) 1 to 17 were produced.
[0020]
On the other hand, C: 1.0, Si: 0.26%, Mn: 0.13%, Cr: 3.14%, Mo: 3.37% in the weight percentages described in JP-A-11-21659. , V: 0.25%, Co: 6.0% and CaF2: 5%, and further, a particle size: 10 μm of Cr—Mo—Si—Co intermetallic compound: 10% so as to be 20 area% In addition, a conventional iron-based sintered alloy (hereinafter referred to as a conventional alloy) including the balance Fe and inevitable impurities was prepared.
[0021]
The following wear tests were performed on the inventive alloys 1 to 17 and the conventional alloys.
[0022]
A valve made of SUH36 material and having an umbrella part with an outer diameter of 30 mm is prepared. The valve umbrella part is maintained at a temperature of 900 ° C., and a valve seat made of the alloys 1 to 17 of the present invention and a conventional alloy is prepared. Each of these valve seats was press-fitted into a water-cooled jig and tested for 150 hours in a natural gas combustion atmosphere under a seating load of 30 kg and a valve seating frequency of 3000 times / minute. The maximum amount of wear was measured, and the results are shown in Tables 4-5.
[0023]
[Table 2]
[0024]
[Table 3]
[0025]
[Table 4]
[0026]
[Table 5]
[0027]
From the results shown in Tables 4 to 5, the valve seats made from the alloys 1 to 17 of the present invention have less wear of the valve seat than the valve seats made from the conventional alloys. No. 17 has excellent wear resistance compared to the conventional alloy, and the alloys 1 to 17 of the present invention have less counter attack from the point that the maximum wear amount of the valve, which is the counterpart material, is smaller than that of the conventional alloy. .
[0028]
【The invention's effect】
As described above, the iron-base metal bond of the present invention has a higher wear resistance than the conventional one, and has a low opponent attack against the counterpart valve, and thus greatly contributes to the development of the automotive industry such as engines. To get.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is an explanatory view for explaining the structure of an iron-base bond gold according to the present invention.
FIG. 2 is an explanatory diagram for explaining the structure of a conventional iron-base bond gold.
[Explanation of symbols]
Vacancies 1 CaF 2 particles 2 pores 3 matrix 4 sharp edges 5 crack 6 CaF 2 has Deki fall off

Claims (6)

  1. Cu:8〜40重量%、CaF:0.5〜10重量%を含有し、残りがFeおよび不可避不純物からなる組成を有し、かつ前記CaF2は素地の気孔内部に存在して分散している組織を有することを特徴とする鉄基焼結合金。Cu: 8 to 40% by weight, CaF 2 : 0.5 to 10% by weight, the remainder is composed of Fe and inevitable impurities, and the CaF 2 is present and dispersed inside the pores of the substrate An iron-based sintered alloy characterized by having a microstructure.
  2. Cu:8〜40重量%、CaF2:0.5〜10重量%、Ni:0.5〜10重量%を含有し、残りがFeおよび不可避不純物からなる組成を有し、かつ前記CaF2は素地の気孔内部に存在して分散している組織を有することを特徴とする鉄基焼結合金。Cu: 8 to 40% by weight, CaF 2 : 0.5 to 10% by weight, Ni: 0.5 to 10% by weight, with the remainder consisting of Fe and inevitable impurities, and the CaF 2 is An iron-based sintered alloy characterized by having a dispersed structure existing inside pores of a substrate.
  3. Cu:8〜40重量%、CaF2:0.5〜10重量%、C:0.05〜3重量%を含有し、残りがFeおよび不可避不純物からなる組成を有し、かつ前記CaF2は素地の気孔内部に存在して分散している組織を有することを特徴とする鉄基焼結合金。Cu: 8 to 40% by weight, CaF 2 : 0.5 to 10% by weight, C: 0.05 to 3% by weight, with the remainder consisting of Fe and inevitable impurities, and the CaF 2 is An iron-based sintered alloy characterized by having a dispersed structure existing inside pores of a substrate.
  4. Cu:8〜40重量%、CaF2:0.5〜10重量%、Ni:0.5〜10重量%、C:0.05〜3重量%を含有し、残りがFeおよび不可避不純物からなる組成を有し、かつ前記CaF2は素地の気孔内部に存在して分散している組織を有することを特徴とする鉄基焼結合金。Cu: 8 to 40% by weight, CaF 2 : 0.5 to 10% by weight, Ni: 0.5 to 10% by weight, C: 0.05 to 3% by weight, with the remainder consisting of Fe and inevitable impurities An iron-based sintered alloy having a composition and having a structure in which the CaF 2 is present and dispersed inside the pores of the substrate.
  5. Cu:8〜40重量%、CaF2:0.5〜10重量%、Ni:0.5〜10重量%を含有し、さらにCr,Mn,Mo,W,V,Si,Co,Nbのうち1種または2種以上を合計で0.5〜20重量%を含有し、残りがFeおよび不可避不純物からなる組成を有し、かつ前記CaF2は素地の気孔内部に存在して分散している組織を有することを特徴とする鉄基焼結合金。Cu: 8 to 40 wt%, CaF 2: 0.5 to 10 wt%, Ni: contained 0.5 to 10 wt%, further Cr, Mn, Mo, W, V, Si, Co, among Nb 1 type or 2 types or more are contained in a total of 0.5 to 20% by weight, and the remainder has a composition composed of Fe and inevitable impurities, and the CaF 2 is present and dispersed inside the pores of the substrate. An iron-based sintered alloy characterized by having a structure.
  6. Cu:8〜40重量%、CaF2:0.5〜10重量%、Ni:0.5〜10重量%、C:0.05〜3重量%を含有し、さらにCr,Mn,Mo,W,V,Si,Co,Nbのうち1種または2種以上を合計で0.5〜20重量%を含有し、残りがFeおよび不可避不純物からなる組成を有し、かつ前記CaF2は素地の気孔内部に存在して分散している組織を有することを特徴とする鉄基焼結合金。Cu: 8 to 40 wt%, CaF 2: 0.5 to 10 wt%, Ni: 0.5 to 10 wt%, C: 0.05 to 3 containing wt%, further Cr, Mn, Mo, W , V, Si, Co, Nb, or a total of 0.5 to 20% by weight of one or more of Nb, with the balance being composed of Fe and inevitable impurities, and the CaF 2 is a base material. An iron-based sintered alloy having a structure in which pores exist and are dispersed.
JP2000022160A 2000-01-31 2000-01-31 Iron-based sintered alloy Expired - Fee Related JP3942136B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2000022160A JP3942136B2 (en) 2000-01-31 2000-01-31 Iron-based sintered alloy

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2000022160A JP3942136B2 (en) 2000-01-31 2000-01-31 Iron-based sintered alloy

Publications (2)

Publication Number Publication Date
JP2001214245A JP2001214245A (en) 2001-08-07
JP3942136B2 true JP3942136B2 (en) 2007-07-11

Family

ID=18548493

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2000022160A Expired - Fee Related JP3942136B2 (en) 2000-01-31 2000-01-31 Iron-based sintered alloy

Country Status (1)

Country Link
JP (1) JP3942136B2 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107838413A (en) * 2017-09-30 2018-03-27 东风商用车有限公司 A kind of heavy-duty engine powder metallurgy material for valve seat insert and preparation method thereof

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5070920B2 (en) * 2007-05-08 2012-11-14 トヨタ自動車株式会社 Overlay wear-resistant iron-base alloy
JP2011094167A (en) * 2009-10-27 2011-05-12 Diamet:Kk Iron-copper based sintered sliding member, and method for producing the same
CN103899376A (en) * 2013-09-30 2014-07-02 安徽金亿合金新材料有限公司 Natural gas engine valve guide pipe

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107838413A (en) * 2017-09-30 2018-03-27 东风商用车有限公司 A kind of heavy-duty engine powder metallurgy material for valve seat insert and preparation method thereof
CN107838413B (en) * 2017-09-30 2021-03-16 东风商用车有限公司 Heavy-duty engine powder metallurgy valve seat material and preparation method thereof

Also Published As

Publication number Publication date
JP2001214245A (en) 2001-08-07

Similar Documents

Publication Publication Date Title
JP4213060B2 (en) Ferrous sintered alloy material for valve seats
JP3952344B2 (en) Wear-resistant iron-based sintered alloy material for valve seat and valve seat made of iron-based sintered alloy
JP4584158B2 (en) Valve seat material made of iron-based sintered alloy for internal combustion engines
JP2004124162A (en) Manufacturing method of iron-based sintered alloy valve seat exhibiting wear resistance under high surface pressure applied condition
JP2001050020A (en) Valve device for internal combustion engine
KR0127658B1 (en) VALVE GUIDE MEMBER FORMED OF Fe-BASED SINTERED ALLOY HAVING EXCELLENT WEAR AND ABRASION
JP3469435B2 (en) Valve seat for internal combustion engine
JP6386676B2 (en) Sintered valve seat
JP5823697B2 (en) Ferrous sintered alloy valve seat
JP2017025921A (en) Sintered valve seat and process of manufacture of sintered valve seat
JP4948636B2 (en) Hard particles for blending sintered alloys, wear-resistant iron-based sintered alloys, and valve seats
JP4624600B2 (en) Sintered alloy, manufacturing method thereof and valve seat
JP2010144238A (en) Wear-resistant sintered alloy and method for producing the same
WO2015141331A1 (en) Valve seat constituted of iron-based sintered alloy
JP2007238987A (en) Wear resistant sintered alloy and its production method
JP3942136B2 (en) Iron-based sintered alloy
JP3763782B2 (en) Method for producing wear-resistant iron-based sintered alloy material for valve seat
JP2005154798A (en) Alloy powder for forming hard phase, iron-based mixed powder using the same, method for manufacturing abrasion-resistant sintered alloy, and abrasion-resistant sintered alloy
JP3225649B2 (en) Wear resistant iron-based sintered alloy
JPH06179937A (en) Sintered alloy for valve seat
JP2000054087A (en) Iron-base sintered alloy material for valve seat, and its manufacture
JP2013173961A (en) Valve seat made from iron-based sintered alloy
JP3068127B2 (en) Wear-resistant iron-based sintered alloy and method for producing the same
JP3275729B2 (en) Method for producing valve seat made of Fe-based sintered alloy with excellent wear resistance
JP2006193831A (en) Abrasion resistance iron-based sintered alloy material for valve seat and valve seat made of iron-based sintered alloy

Legal Events

Date Code Title Description
A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20040329

A977 Report on retrieval

Free format text: JAPANESE INTERMEDIATE CODE: A971007

Effective date: 20050613

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20050621

A521 Written amendment

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20050818

A711 Notification of change in applicant

Free format text: JAPANESE INTERMEDIATE CODE: A712

Effective date: 20060124

RD03 Notification of appointment of power of attorney

Free format text: JAPANESE INTERMEDIATE CODE: A7423

Effective date: 20060214

TRDD Decision of grant or rejection written
A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

Effective date: 20070402

A61 First payment of annual fees (during grant procedure)

Free format text: JAPANESE INTERMEDIATE CODE: A61

Effective date: 20070402

R150 Certificate of patent or registration of utility model

Free format text: JAPANESE INTERMEDIATE CODE: R150

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20100413

Year of fee payment: 3

S531 Written request for registration of change of domicile

Free format text: JAPANESE INTERMEDIATE CODE: R313531

S533 Written request for registration of change of name

Free format text: JAPANESE INTERMEDIATE CODE: R313533

R360 Written notification for declining of transfer of rights

Free format text: JAPANESE INTERMEDIATE CODE: R360

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20100413

Year of fee payment: 3

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20100413

Year of fee payment: 3

S531 Written request for registration of change of domicile

Free format text: JAPANESE INTERMEDIATE CODE: R313532

S533 Written request for registration of change of name

Free format text: JAPANESE INTERMEDIATE CODE: R313533

R370 Written measure of declining of transfer procedure

Free format text: JAPANESE INTERMEDIATE CODE: R370

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20100413

Year of fee payment: 3

R350 Written notification of registration of transfer

Free format text: JAPANESE INTERMEDIATE CODE: R350

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20110413

Year of fee payment: 4

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20120413

Year of fee payment: 5

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20130413

Year of fee payment: 6

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20140413

Year of fee payment: 7

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

LAPS Cancellation because of no payment of annual fees