JP2001172751A - Fe-BASE HEAT-RESISTING ALLOY FOR ENGINE VALVE, WITH EXCELLENT COLD WORKABILITY AND HIGH TEMPERATURE STRENGTH - Google Patents
Fe-BASE HEAT-RESISTING ALLOY FOR ENGINE VALVE, WITH EXCELLENT COLD WORKABILITY AND HIGH TEMPERATURE STRENGTHInfo
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Abstract
Description
【０００１】[0001]
【発明が属する技術分野】本発明は、冷間加工性が良好
で、かつ優れた高温強度を有し、安価な冷間鍛造により
作製される排気エンジンバルブ用耐熱合金に関するもの
である。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-resistant alloy for an exhaust engine valve having good cold workability, excellent high-temperature strength, and produced by inexpensive cold forging.
【０００２】[0002]
【従来の技術】今日、耐熱鋼及び超耐熱合金は多くの用
途に用いられているが、代表的な用途の一つに排気エン
ジンバルブが挙げられる。2. Description of the Related Art Today, heat-resistant steels and super-heat-resistant alloys are used in many applications. One of the typical applications is an exhaust engine valve.
【０００３】従来、ガソリンエンジンやディーゼルエン
ジンの排気バルブ用材料としては高Mn系のγ鋼であるSU
H35(Fe-8.5Mn-21Cr-4Ni-0.5C-0.4N)が広く使用されてき
た。一部使用温度の高いエンジン及び高負荷となるエン
ジンには、NCF751(Ni-15.5Cr-1Nb-2.3Ti-1.2Al-7Fe) が
使用されるに至ってきた。Conventionally, as a material for an exhaust valve of a gasoline engine or a diesel engine, SU which is a high Mn gamma steel has been used.
H35 (Fe-8.5Mn-21Cr-4Ni-0.5C-0.4N) has been widely used. NCF751 (Ni-15.5Cr-1Nb-2.3Ti-1.2Al-7Fe) has come to be used for engines that are partially used at high temperatures and for engines that have high loads.
【０００４】しかし、NCF751はNiを約70% も含み非常に
高価であるために最近ではNCF751よりも省資源でかつNC
F751に近い高温強度、組織安定性を有する合金の開発が
行われてきた。更に、特に最近では自動車に使用される
部品においては長時間使用後の特性劣化の抑制、使用材
料の組織安定性が要求されてきている。However, since NCF751 is very expensive including about 70% of Ni, it has recently been required to save resources and to reduce the cost of NCF751.
Alloys with high-temperature strength and structural stability close to F751 have been developed. Furthermore, recently, particularly for parts used in automobiles, suppression of characteristic deterioration after long-term use and structural stability of materials used have been required.
【０００５】その要求を満たす提案として、発明者ら
は、例えば特開平7-109539号には、重量％でC:0.10% 以
下、Si:1.0% 以下、Mn:3.0% 以下、Ni:30 〜49% 、Cr:1
0 〜18% 、Al:1.6〜3.0%、を含み、a 属とVa属から選ば
れる一種または二種以上の元素を合計で1.5 〜6.0%含有
し、かつ原子% でAl、Ti、Zr、Hf、V 、Nb、Taの関係式
及び原子% でCr、Mo、W の関係式を規定することによ
り、長時間加熱後の特性劣化の抑制、組織安定性を改善
した合金を提案した。[0005] As a proposal satisfying the requirements, for example, Japanese Patent Application Laid-Open No. 7-109539 discloses that in weight percent C: 0.10% or less, Si: 1.0% or less, Mn: 3.0% or less, Ni: 30% or less. 49%, Cr: 1
0 to 18%, Al: 1.6 to 3.0%, contains 1.5 to 6.0% in total of one or more elements selected from the genus a and the genus Va, and contains Al, Ti, Zr, By defining the relational expressions of Hf, V, Nb, and Ta and the relational expressions of Cr, Mo, and W in atomic%, we proposed an alloy that suppressed the deterioration of characteristics after long-time heating and improved the structural stability.
【０００６】[0006]
【発明が解決しようとする課題】排気エンジンバルブの
成形方法としては熱間アップセット工法、熱間押し出し
工法及び冷間鍛造法の種々の工法が存在し、現在は熱間
アップセット工法、熱間押し出し工法が主に行われてい
る。There are various methods for forming an exhaust engine valve, such as a hot upset method, a hot extrusion method and a cold forging method. The extrusion method is mainly used.
【０００７】しかし、現在行われている熱間成形法で
は、寸法精度や多工数等の問題があるために、品質向上
やコスト低減を目的とした工数削減が求められている。
これらの要求を解決するためにエンジンバルブを冷間鍛
造で成型することが提案されている。この方法は、単位
時間内で多数のエンジンバルブ製造が可能であるため
に、工数削減によるコスト低減が見込まれる。However, in the hot forming method which is currently performed, there are problems such as dimensional accuracy and many man-hours, and therefore, man-hour reduction for the purpose of quality improvement and cost reduction is required.
In order to solve these requirements, it has been proposed to form the engine valve by cold forging. According to this method, since a large number of engine valves can be manufactured in a unit time, cost reduction is expected due to reduction of man-hours.
【０００８】また、冷間鍛造成型した後に時効硬化処理
をすることで、材料を硬化させた状態で使用すれば、従
来の熱間成型した場合と比較して、使用時の硬さも従来
の場合と比較して大きく上昇させると期待される。In addition, when the material is used in a hardened state by performing an age hardening treatment after cold forging, the hardness during use is lower than that in the conventional hot forming. It is expected to increase significantly compared to.
【０００９】しかしながら、エンジンバルブとして使用
した場合において、高温に長時間さらされた時に組織が
不安定化して、強度が低下する危険性もあるので、対象
となる合金選定やその合金の成分調整には、十分な選択
と注意が必要である。However, when used as an engine valve, there is a risk that the structure will become unstable and the strength will decrease when exposed to a high temperature for a long time. Therefore, it is necessary to select a target alloy and adjust the composition of the alloy. Requires careful choice and care.
【００１０】例えば、この冷間鍛造するエンジンバルブ
材に、従来から使用されているSUH35 を用いると、C 量
が高いために固溶化処理後の硬さを低減させることが難
しく、かつMn量が高いために加工硬化を起こすために冷
間鍛造により作製することは困難であった。For example, when conventionally used SUH35 is used as the cold forged engine valve material, it is difficult to reduce the hardness after the solution treatment because the C content is high, and the Mn content is low. Due to its high cost, it was difficult to produce it by cold forging to cause work hardening.
【００１１】また、特開平7-109539号に開示されている
合金は、エンジンバルブとして必要な性能である高温強
度については、十分な特性を有するが、変形抵抗が高い
ために、エンジンバルブを冷間鍛造することが困難であ
るという問題があった。The alloy disclosed in Japanese Patent Application Laid-Open No. 7-109539 has sufficient characteristics for high-temperature strength, which is a performance required for an engine valve. However, there is a problem that it is difficult to forge the steel.
【００１２】本発明の目的は、冷間鍛造が可能で、かつ
冷間鍛造後の直接時効処理によって強度の向上が見込ま
れる耐熱合金として、コストが比較的安価である特開平
7-109539号に開示する合金について、高温強度と組織安
定性を確保する元素範囲を大きく変えることなく、冷間
鍛造性を改善した耐熱合金を提供することである。An object of the present invention is to provide a heat-resistant alloy which can be cold forged and whose strength is expected to be improved by a direct aging treatment after the cold forging.
An object of the present invention is to provide a heat-resistant alloy having improved cold forgeability without greatly changing the element range for ensuring the high-temperature strength and the structural stability of the alloy disclosed in No. 7-109539.
【００１３】[0013]
【課題を解決するための手段】本発明者等は、特開平7-
109539号の合金を基に冷間鍛造性を改善する各合金元素
の最適化を行った。Means for Solving the Problems The present inventors have disclosed in Japanese Patent Laid-Open No.
Based on the alloy of No. 109539, optimization of each alloy element to improve cold forgeability was performed.
【００１４】本発明者等の検討によれば、高温強度に関
しては、特開平7-109539号に記載の合金の発明手法がそ
のまま利用でき、マトリクスとなるγ相と、析出強化相
となるγ' 相の両相の組成の最適化と両相の量比を最適
化することにより達成されることを知見した。According to the study of the present inventors, the high-temperature strength can be directly applied to the alloy invention disclosed in Japanese Patent Application Laid-Open No. 7-109539, and a γ phase serving as a matrix and a γ ′ serving as a precipitation strengthening phase can be used. It has been found that this can be achieved by optimizing the composition of both phases of the phase and optimizing the quantitative ratio of both phases.
【００１５】一方、冷間鍛造性は、析出強化相となる
γ' 相を構成する元素を、マトリクスであるγ相中に完
全に固溶させた状態、即ち、Feをベースとする高いNi量
と高いCr量を含有するγ相中に、種々の元素を基本的に
Fe原子を置換する形で固溶させた相状態において冷間加
工するときの変形抵抗によって良否を判断する必要があ
る。On the other hand, the cold forgeability is determined by a state in which the elements constituting the γ 'phase serving as the precipitation strengthening phase are completely dissolved in the γ phase serving as the matrix, that is, a high Ni content based on Fe. And various elements in the γ phase containing high Cr content
It is necessary to judge pass / fail based on deformation resistance at the time of cold working in a phase state in which a solid solution is formed by replacing Fe atoms.
【００１６】高温強度と冷間鍛造性は相反する性能であ
るが、本発明者等は、以上の知見を踏まえ、特開平7-10
9539号に記載された開示合金に対してNi、Co、Mo、C 、
Al、Ti、Nb等の種々の合金元素を最適に制御することで
強度と冷間加工性がともに良好で、両者の特性のバラン
スを保った合金を見出し、本発明に到達した。Although the high-temperature strength and the cold forgeability are contradictory performances, the present inventors have taken the above findings into consideration in Japanese Patent Application Laid-Open No.
For the disclosed alloy described in No. 9539, Ni, Co, Mo, C,
By optimally controlling various alloying elements such as Al, Ti, and Nb, the present inventors have found an alloy having both good strength and good cold workability and maintaining a balance between the two properties, and reached the present invention.
【００１７】即ち本発明は、重量％でC:0.08% 以下、S
i:1.0% 以下、Mn:1.0% 以下、Ni及び3.0 以下(0% を含
む) のCoを合計で25% を超え30% 未満、Cr:10 〜18% 、
Al:1.2〜2.5%、Ti:1.5〜3.0 、IVa 族とVa族から選ばれ
る一種または二種以上の元素を合計で1.5 〜6.0%を含
み、残部は不純物を除き実質的にFeからなる良好な冷間
加工性及び高温強度を具備したエンジンバルブ用Fe基耐
熱合金である。That is, according to the present invention, C: not more than 0.08% by weight,
i: 1.0% or less, Mn: 1.0% or less, Ni and 3.0 or less (including 0%) Co in total exceeding 25% and less than 30%, Cr: 10 to 18%,
Al: 1.2 to 2.5%, Ti: 1.5 to 3.0, containing 1.5 to 6.0% in total of one or two or more elements selected from the IVa group and the Va group, with the balance being substantially Fe, excluding impurities Fe-based heat-resistant alloy for engine valves having excellent cold workability and high-temperature strength.
【００１８】好ましくは、重量％でC:0.05以下、Si:0.5
以下、Mn:0.5以下、Ni及び3.0 以下(0% を含む) のCoを
合計で26.5〜28.5、Cr:12 〜16、Al:1.2〜2.5 、Ti:1.5
〜3.0 、Nb:0.2〜2.0 を含み、残部は不純物を除き実質
的にFeからなる良好な冷間加工性及び高温強度を具備し
たエンジンバルブ用Fe基耐熱合金であり、重量％でMo:3
% 以下とW:3%以下の一種または二種を含んでも良く、更
に好ましくは、重量%で、0.015%以下のB を含む。Preferably, C: 0.05 or less and Si: 0.5% by weight
Hereinafter, Mn: 0.5 or less, Ni and 3.0 or less (including 0%) Co in total 26.5 to 28.5, Cr: 12 to 16, Al: 1.2 to 2.5, Ti: 1.5
~ 3.0, Nb: 0.2 ~ 2.0, the remainder is Fe-based heat-resistant alloy for engine valves with good cold workability and high-temperature strength consisting essentially of Fe excluding impurities.
% Or less and one or two kinds of W: 3% or less, more preferably 0.015% or less by weight of B 2.
【００１９】また、上記合金は原子% でAlの含有量と他
元素の含有量を、下記関係式を満たすのが良い。The above alloy preferably satisfies the following relational expression in terms of the content of Al and the content of other elements in atomic%.
【００２０】0.50≦[Al]/([Al]+[Ti]+[Zr]+[Hf]+[V]+[N
b]+[Ta])≦0.60 或いは、上記合金は、原子% でCrの含有量と他元素の含
有量を、下記関係式を満たすのが望ましい。0.50 ≦ [Al] / ([Al] + [Ti] + [Zr] + [Hf] + [V] + [N
b] + [Ta]) ≦ 0.60 Alternatively, in the above alloy, it is desirable that the content of Cr and the content of other elements in atomic% satisfy the following relational expression.
【００２１】0.14≦([Cr]+[Mo]+[W])/([Ni]+[Co]+[Fe]+
[Cr]+[Mo]+[W])≦0.20 本発明で更に好ましくは、重量% で、0.01% 以下のY と
0.01% 以下のREM の一種または二種を含む。0.14 ≦ ([Cr] + [Mo] + [W]) / ([Ni] + [Co] + [Fe] +
[Cr] + [Mo] + [W]) ≦ 0.20 In the present invention, more preferably, Y and 0.01% by weight or less are used.
Contains one or two REMs of 0.01% or less.
【００２２】上記の本発明のFe基耐熱合金は、60% 〜80
% 冷間加工の後に800 ℃で、400 時間加熱後の800 ℃-2
45MPa で回転曲げ疲労試験を行った際の破断回数が1.0
×10 6 回以上であり、更に、70% 冷間加工を行う際に要
する真応力を1800MPa 以下である。The above-mentioned Fe-based heat-resistant alloy of the present invention has a content of 60% to 80%.
% 800 ° C after cold working, 800 ° C-2 after heating for 400 hours
The number of breaks in the rotational bending fatigue test at 45 MPa was 1.0
× 10 6Or more times, and also required for 70% cold working.
Is less than or equal to 1800 MPa.
【００２３】[0023]
【発明の実施の形態】本発明は、Niを始めとした固溶元
素の添加量を高温強度に必要な最小限量にとどめ、各元
素量の最適化を図り、強度と冷間加工性がともに良好
で、両者の特性のバランスを保ちつつ、特に冷間加工性
を向上させたエンジンバルブ用Fe基耐熱合金を提供する
ものである。BEST MODE FOR CARRYING OUT THE INVENTION The present invention minimizes the amount of solid solution elements such as Ni added to the minimum required for high-temperature strength, optimizes the amounts of each element, and achieves both strength and cold workability. An object of the present invention is to provide an Fe-base heat-resistant alloy for an engine valve, which is favorable and has particularly improved cold workability while maintaining a balance between the two properties.
【００２４】以下に本発明で規定する各元素の限定理由
を説明する。先ず、C はTiやNb、Ta等と結びついてMC炭
化物を形成し、結晶粒の粗大化を防止する作用があるた
めに少量添加する必要がある。しかし0.08% を超える過
度の添加は硬さを上昇させて、冷間加工性を劣化させ、
更に長時間加熱時にMCからM2 3C6 へ分解反応を起こし
て、常温における粒界の延性を低下させる。The reasons for limiting each element specified in the present invention will be described below. First, C is combined with Ti, Nb, Ta, etc. to form MC carbides and has an effect of preventing the crystal grains from becoming coarse, so that a small amount of C must be added. However, excessive addition exceeding 0.08% increases the hardness, deteriorating the cold workability,
Furthermore, when heated for a long time, a decomposition reaction occurs from MC to M 2 3 C 6, and the ductility of grain boundaries at room temperature is reduced.
【００２５】更に実際にバルブを冷間鍛造する際にMC炭
化物が多いと、バルブ成形時にその炭化物を起点にして
割れる危険性がある。よってC は0.08% 以下とする。よ
り好適なC の範囲は0.05% 以下である。Further, when the valve is actually cold forged, if there is a large amount of MC carbide, there is a risk that the valve may be cracked starting from the carbide during molding. Therefore, C is set to 0.08% or less. A more preferred C range is 0.05% or less.
【００２６】SiとMnは本発明合金において脱酸元素とし
て添加されるが、いずれも過度の添加は高温強度の低下
を招く。更にMnについては変形抵抗を上昇させて冷間加
工性を低下させるために各々1.0%以下と低くした。更に
好適な範囲は各々0.5%以下である。Although Si and Mn are added as deoxidizing elements in the alloy of the present invention, excessive addition of both causes reduction in high-temperature strength. Mn was further reduced to 1.0% or less in order to increase deformation resistance and reduce cold workability. More preferred ranges are each 0.5% or less.
【００２７】Niはマトリクスのγ相を安定化させると共
に高温強度も高める。更にγ' 相の構成元素として必須
の元素である。Ni stabilizes the γ phase of the matrix and increases the high-temperature strength. Further, it is an essential element as a constituent element of the γ 'phase.
【００２８】また、Coはγマトリクスに固溶してγ相を
安定化させるとともに、熱間加工領域ではγ' 相の固溶
を促進させて熱間加工性を改善し、更に、実用温度領域
ではγ' 相の析出量を増加させ、高温強度を向上させ
る。In addition, Co forms a solid solution in the γ matrix to stabilize the γ phase, and in the hot working region, promotes the solid solution of the γ ′ phase to improve hot workability. Increases the precipitation amount of the γ 'phase and improves the high-temperature strength.
【００２９】このNiとCoは、ともにγ相を安定化させ、
高温強度を上昇させる点で同じ働きをするためにCoはNi
に置換する形で添加することを可能とするが、CoはNiよ
り高価な元素であるため、添加する場合には3%以下が良
い。Both Ni and Co stabilize the γ phase,
Co is Ni in order to do the same in increasing the high temperature strength.
Can be added in the form of substitution, but since Co is an element more expensive than Ni, when Co is added, the content is preferably 3% or less.
【００３０】そして、Ni及び3.0 以下(0% を含む) のCo
が合計で25% 以下の場合には、強化に寄与するγ' 相の
析出量が少なくなるために強度が不十分となる。またマ
トリクスの組織が不安定化しγ' 相そのものの粗大化が
起こり高温強度が低下する恐れがある。一方、Ni及び3.
0 以下(0% を含む) のCoが合計で30% 以上添加すると変
形抵抗が上昇して冷間加工性が劣化する。Then, Ni and Co of 3.0 or less (including 0%)
Is less than 25% in total, the strength becomes insufficient because the amount of the γ 'phase contributing to strengthening is reduced. In addition, the matrix structure may be destabilized and the γ 'phase itself may become coarse, resulting in a decrease in high-temperature strength. On the other hand, Ni and 3.
If a total of 0% or less (including 0%) of Co is added at 30% or more, the deformation resistance increases and the cold workability deteriorates.
【００３１】従って、Ni及び3.0 以下(0% を含む) のCo
を合計で25％を超え30% 未満の範囲に限定する。より望
ましい範囲は26.5〜28.5% である。Therefore, Ni and Co of 3.0 or less (including 0%)
Is limited to a range of more than 25% and less than 30% in total. A more desirable range is 26.5-28.5%.
【００３２】Crは合金の耐酸化性を向上させるために必
要不可欠な元素であり、最低10% は必要であるが、18%
を超えるとCrに富んだシグマ( σ) 相、マルテンサイト
( α')相もしくはフェライト( α) 相を析出し、長時間
加熱後の組織安定性を劣化させ、また、変形抵抗も上昇
して冷間加工性を低下させるために10〜18% とする。よ
り望ましい範囲は12〜16% である。Cr is an indispensable element for improving the oxidation resistance of the alloy, and at least 10% is necessary, but 18%
Above the chromium-rich sigma (σ) phase, martensite
Precipitate the (α ') phase or ferrite (α) phase, degrade the structure stability after long-time heating, and increase the deformation resistance to reduce the cold workability by 10 to 18%. . A more desirable range is 12-16%.
【００３３】Alは安定なγ' 相を析出させて要求される
高温強度を得るために本発明において不可欠な元素でか
つ、冷間加工性も向上させる元素である。従って、最低
1.2%は必要であり、2.5%を超えると熱間加工性を低下さ
せるので1.2 〜2.5%に限定する。より好適な範囲は1.5
〜2.0%である。Al is an element indispensable in the present invention for precipitating a stable γ 'phase and obtaining a required high-temperature strength, and is also an element for improving cold workability. Therefore, at least
1.2% is necessary, and if it exceeds 2.5%, the hot workability is reduced, so it is limited to 1.2 to 2.5%. A more preferred range is 1.5
~ 2.0%.
【００３４】TiはNi、Alと共にγ' 相を形成し、γ' 相
を強化して高温強度を向上させるので、1.5%以上必要で
あるが3.0%以上添加すると冷間加工性が低下し、また高
温においてγ' 相がイータ( η：Ｎｉ3 Ｔｉ) 相へ変態
し、高温強度を低下させるので1.5 〜3.0%に限定する。
より好適な範囲は1.8 〜2.5%である。Since Ti forms a γ ′ phase together with Ni and Al and strengthens the γ ′ phase to improve high-temperature strength, 1.5% or more is required. At high temperatures, the γ 'phase is transformed into an eta (η: Ni 3 Ti) phase, which lowers the high-temperature strength, so the content is limited to 1.5 to 3.0%.
A more preferred range is 1.8-2.5%.
【００３５】IVa 族、Va族の元素は、本発明合金におい
て、Alと共にNiと結びついてγ' 相を形成し、γ' 相を
強化して高温強度を向上させる作用があり、一種または
二種以上を合計で1.5%以上添加する必要がある。しか
し、これらの元素が合計で6.0%を越えると、熱間加工性
を劣化させ、かつ高温長時間加熱後にγ' 相が不安定と
なってη相やデルタ( δ：Ｎｉ3 Ｎｂ) 相へ変態し、組
織安定性が低下するので1.5 〜6.0%に限定する。より好
適な範囲は3.0 〜5.0%である。In the alloys of the present invention, the elements belonging to the group IVa and Va form an γ 'phase by binding with Ni together with Al to form a γ' phase, thereby strengthening the γ 'phase and improving the high-temperature strength. It is necessary to add 1.5% or more in total. However, if these elements exceed 6.0% in total, the hot workability is deteriorated, and the γ 'phase becomes unstable after heating at a high temperature for a long time, so that the γ phase and the delta (δ: Ni 3 Nb) phase are formed. It is limited to 1.5 to 6.0% because of metamorphosis and reduced tissue stability. A more preferred range is 3.0-5.0%.
【００３６】IVa 族の元素においてはTiの添加が好まし
い。ZrとHfはγへの固溶度がTiより低く、Tiほど多量に
は添加できない。V a 族の元素ではNbの添加がもっとも
好ましく0.2 〜2.0%添加するのが良い。より好適な範囲
は0.3 〜1.2%である。In the group IVa element, the addition of Ti is preferred. Zr and Hf have a lower solid solubility in γ than Ti, and cannot be added in a larger amount than Ti. Of the elements of the Va group, Nb is most preferably added, and 0.2 to 2.0% is preferably added. A more preferred range is from 0.3 to 1.2%.
【００３７】一方、V はNbより固溶強化作用が弱く、耐
酸化性も低下させるので過度の添加は好ましくない。Ta
はNb以上にγ' を固溶強化させるが希少資源で高価であ
るので多量の添加は好ましくない。On the other hand, V has a weaker solid solution strengthening action than Nb and also lowers the oxidation resistance, so excessive addition is not preferred. Ta
Although γ ′ is solid-solution strengthened more than Nb, it is a rare resource and expensive, so addition of a large amount is not preferable.
【００３８】MoとW はCrと同様にγマトリクスに固溶強
化し、高温疲労強度と高温クリープ破断強度を向上させ
る効果を有する。そのために必要に応じて一種または二
種を3%以下の範囲で添加できる。しかし、Crを含めたこ
れらの元素添加のマトリクスに対する比が高温長時間加
熱後におけるσ相やα' 相及びα相の析出に寄与してく
るために下記関係式を満たすことが望ましい。即ち、原
子% でB 値をB=([Cr]+[Mo]+[W])/([Ni]+[Co]+[Fe]+[Cr]
+[Mo]+[W])として、0.14≦B ≦0.20である。Like Cr, Mo and W are solid-solution strengthened in a γ matrix, and have the effect of improving high-temperature fatigue strength and high-temperature creep rupture strength. Therefore, if necessary, one or two kinds can be added in a range of 3% or less. However, since the ratio of the addition of these elements including Cr to the matrix contributes to the precipitation of the σ phase, α 'phase and α phase after heating at a high temperature for a long time, it is desirable to satisfy the following relational expression. That is, the B value is expressed as B = ([Cr] + [Mo] + [W]) / ([Ni] + [Co] + [Fe] + [Cr]
+ [Mo] + [W]), and 0.14 ≦ B ≦ 0.20.
【００３９】本発明合金の特徴である冷間鍛造により製
造したバルブにおいて高温長時間加熱後にも特性劣化し
ないということを達成するには上記の如く、Cr、Mo、W
量の規定の他にNi、Alと共にγ' 相を形成するIVa 族、
V a 族についても限定する必要がある。As described above, in order to achieve the characteristics of the valve manufactured by cold forging, which is a feature of the alloy of the present invention, that the characteristics do not deteriorate even after heating at a high temperature for a long time, as described above, Cr, Mo, W
Group IVa which forms a γ 'phase with Ni and Al,
The V a group also needs to be limited.
【００４０】即ち、原子% でA 値=[Al]/([Al]+[Ti]+[Z
r]+[Hf]+[V]+[Nb]+[Ta]) 値を高めることによりγ' 相
の高温での安定性を向上させることが可能となるが、A
値が高すぎると長時間高温強度を低下させる。従って、
上記A 値は0.50〜0.60とするのが好ましい。A 値のより
好適な範囲は0.52〜0.58である。That is, A value = [Al] / ([Al] + [Ti] + [Z
r] + [Hf] + [V] + [Nb] + [Ta]) It is possible to improve the stability of the γ 'phase at high temperatures by increasing the value.
If the value is too high, the high-temperature strength for a long time is reduced. Therefore,
The A value is preferably 0.50 to 0.60. A more preferred range for the A value is from 0.52 to 0.58.
【００４１】B （ホウ素）は本発明において粒界強化作
用があり、高温強度及び延性を向上させ、適量添加でき
るが、多量に添加すると初期溶融温度を低下させて熱間
加工性を低下させるために0.015%以下での添加が好まし
い。B (boron) has the effect of strengthening the grain boundary in the present invention, improves high-temperature strength and ductility, and can be added in an appropriate amount. However, if added in a large amount, the initial melting temperature is lowered and hot workability is lowered. Is preferably added at 0.015% or less.
【００４２】MgとCaは脱酸、脱硫元素として合金の清浄
度を高め、高温強度、延性を改善し、一種または二種適
量添加できる。しかし、過度の添加は初期溶融温度を低
下させて熱間加工性を低下させるために各々0.02% 以下
での添加が好ましい。Mg and Ca as deoxidizing and desulfurizing elements increase the cleanliness of the alloy, improve the high-temperature strength and ductility, and can be added in one or two kinds in an appropriate amount. However, excessive addition lowers the initial melting temperature and lowers the hot workability, so that each addition is preferably 0.02% or less.
【００４３】Y 及びREM は本発明において高温での耐酸
化性を高めるのに有効であり、本発明合金に一種または
二種添加できる。しかし、添加量が0.01% を超えると熱
間加工性を低下させるために上限は0.01% とするのが好
ましい。In the present invention, Y and REM are effective in increasing the oxidation resistance at high temperatures, and one or two of them can be added to the alloy of the present invention. However, if the added amount exceeds 0.01%, the hot workability is reduced, so that the upper limit is preferably set to 0.01%.
【００４４】また、上記以外で下記の元素については以
下に示す範囲であれば本発明合金に含まれても良い。 Cu≦0.3%、Ag≦0.2%、P ≦0.04% 、S ≦0.02% 、O ≦0.
02% 、N ≦0.05% より望ましくは Cu≦0.1%、Ag≦0.1%、P ≦0.02% 、S ≦0.005%、O ≦0.
01% 、N ≦0.01% 本発明のFe基耐熱合金をエンジンバルブとする時には、
合金の軟化を目的として、900 〜1050℃の範囲の温度
で、30〜60分保持の固溶化熱処理を施した後、冷間加工
を行う。その際に、大きな冷間歪みが付与され、過剰に
歪が加わればη相の析出が促進されるので、冷間加工の
加工度は60〜80% の範囲内で行うと良い。この冷間加工
後に、エンジンバルブとして必要とされる硬さの付与の
ために例えば720 〜780 ℃で、3 〜5 時間程度の時効処
理を施すことが好ましい。In addition, the following elements other than the above may be included in the alloy of the present invention as long as they are in the following ranges. Cu ≦ 0.3%, Ag ≦ 0.2%, P ≦ 0.04%, S ≦ 0.02%, O ≦ 0.
02%, N ≦ 0.05%, more preferably Cu ≦ 0.1%, Ag ≦ 0.1%, P ≦ 0.02%, S ≦ 0.005%, O ≦ 0.
01%, N ≦ 0.01% When the Fe-base heat-resistant alloy of the present invention is used as an engine valve,
For the purpose of softening the alloy, it is subjected to a solution heat treatment at a temperature in the range of 900 to 1050 ° C. for 30 to 60 minutes, followed by cold working. At that time, a large cold strain is applied, and if excessive strain is applied, the precipitation of the η phase is promoted. Therefore, it is preferable to perform the cold working within a range of 60 to 80%. After the cold working, it is preferable to perform aging treatment at, for example, 720 to 780 ° C. for about 3 to 5 hours in order to impart hardness required for an engine valve.
【００４５】本発明のFe基耐熱合金は、エンジンバルブ
として用いる場合には、運転中のエンジン内の雰囲気温
度700 〜800 ℃に長時間曝されるため、以下の模擬評価
を行うと良い。When the Fe-base heat-resistant alloy of the present invention is used as an engine valve, it is exposed to an ambient temperature of 700 to 800 ° C. for a long time in an operating engine.
【００４６】模擬評価では、上述の60〜80% の冷間加工
を施した試料を用いて、700 〜800℃の温度域に加熱す
る。この時、この温度範囲において、使用中に過剰なη
相の析出が起こり易く、強度が低下するおそれがある80
0 ℃近辺での温度において、400 時間加熱する。In the simulation evaluation, the sample subjected to the cold working of 60 to 80% is heated to a temperature range of 700 to 800 ° C. At this time, in this temperature range, excess η during use is used.
Phase precipitation is likely to occur, and the strength may decrease.80
Heat for 400 hours at a temperature around 0 ° C.
【００４７】そのため、模擬評価は、特別に過酷な条件
下での高温強度の判断基準として、60% 〜80% 冷間加工
の後に800 ℃で、400 時間加熱を施した試料（表３で
は、「長時間加熱（過時効処理）後」として示してい
る。）を、使用温度を想定した800 ℃で、245MPaの回転
曲げ疲労試験に供し、その時の破断回数が1.0 ×106 回
以上であれば良好な高温疲労強度特性が得られるものと
判断した。Therefore, the simulated evaluation was carried out as a criterion for determining the high-temperature strength under particularly severe conditions, in which a sample subjected to heating at 800 ° C. for 400 hours after cold working at 60% to 80% (in Table 3, "After prolonged heating (overage treatment)") was subjected to a 245MPa rotational bending fatigue test at 800 ° C assuming the operating temperature, and if the number of fractures at that time was 1.0 × 10 6 or more It was determined that good high temperature fatigue strength characteristics could be obtained.
【００４８】また、冷間加工性の判断基準として、固溶
化熱処理後の試料で、据え込み圧縮試験を行った際の70
% 加工に相当する真応力値が1800MPa 以下とした。As a criterion for judging the cold workability, 70% of the sample after solution heat treatment was subjected to an upsetting compression test.
% The true stress value corresponding to processing was set to 1800 MPa or less.
【００４９】[0049]
【実施例】表1 、２に試験に供した合金の化学組成を示
す。試料は表1 、２の組成の合金を真空誘導溶解によっ
て10kgのインゴットにした後に熱間加工によって33mmφ
の棒材を作製した。EXAMPLES Tables 1 and 2 show the chemical compositions of the alloys tested. The sample was made into an ingot of 10 kg by vacuum induction melting the alloys of the compositions shown in Tables 1 and 2, and then 33 mmφ by hot working.
Was prepared.
【００５０】この試料を1030℃×30分保持後油冷の固溶
化処理を行ったものについて、常温硬さ測定及び冷間加
工性の試験を行った。硬さはロックウェル硬度計によっ
て測定した。冷間加工性の試験は、φ6 ×9mm の試料を
アムスラー試験機で圧縮荷重をかけて試料の長さを測定
する作業を、荷重を上げていきながら順次繰り返して行
い、圧縮加工率と応力の関係を求めた。これらの試験結
果の常温硬さと冷間圧縮率７０％の時の真応力を表３の
「固溶化熱処理後冷間据込圧縮試験」欄に示す。After holding this sample at 1030 ° C. for 30 minutes and subjecting it to an oil-cooled solution treatment, a normal temperature hardness measurement and a cold workability test were conducted. Hardness was measured with a Rockwell hardness tester. In the cold workability test, the work of measuring the length of a sample of φ6 × 9 mm by applying a compressive load with an Amsler tester and sequentially increasing the load is performed, and the compression work rate and stress Seeking a relationship. The true stress at the room temperature hardness and the cold compressibility of 70% of the test results are shown in the column of "cold upset compression test after solution heat treatment" in Table 3.
【００５１】上記の熱間加工した棒材について、以下に
示す二種類の熱処理を施した。先ず、第一の熱処理は、
1030℃×30分保持後油冷の固溶化処理を行った後に70%
の加工率で冷間引抜きを行い、更に1030℃×30分保持後
油冷の固溶化処理、750 ℃×4 時間保持後空冷の時効処
理を行った試料を「従来熱処理（固溶化熱処理あり）
材」とした。これは、冷間引抜き後に固溶化処理を行っ
て、加工で付与される歪みの影響をなくしたもので、従
来の熱間鍛造工程を行った際の特性に近いものが得られ
ることを予想したものである。The hot-worked rod was subjected to the following two types of heat treatment. First, the first heat treatment
70% after oil-cooled solution treatment after holding at 1030 ° C x 30 minutes
Cold-drawn at a processing rate of, and further subjected to oil-cooled solid solution treatment after holding at 1030 ° C for 30 minutes, and air-cooled aging treatment after holding at 750 ° C for 4 hours and subjected to “conventional heat treatment (with solution treatment heat treatment)”.
Material ". This is a solution treatment performed after cold drawing to eliminate the effect of strain imparted by processing, and it was expected that a material close to the characteristics when a conventional hot forging process was performed would be obtained. Things.
【００５２】次に、第二の熱処理としては、冷間鍛造を
模擬する工程として、1030℃×30分保持後油冷の固溶化
処理を行った後に70% の加工率で冷間引抜きを行い、そ
の後直接750 ℃×4 時間保持後空冷の時効処理を行った
工程とし、この試料を「固溶化熱処理なし( 直接時効)
材」とした。これら２種類の熱処理を行ったそれぞれの
試料を各試験に供した。Next, as a second heat treatment, as a step of simulating cold forging, after being kept at 1030 ° C. for 30 minutes, an oil-cooled solution treatment was performed, and then a cold drawing was performed at a working rate of 70%. Then, directly hold at 750 ° C for 4 hours and then perform air-cooling aging treatment.This sample was treated as `` no solution heat treatment (direct aging)
Material ". Each sample subjected to these two types of heat treatment was subjected to each test.
【００５３】２種類の熱処理を行ったそれぞれについて
引張試験は常温及び800 ℃において行ない、ASTM法によ
り平行部直径6.35mm、伸び4Dにて測定した。引張強さ
は、表３の各々「引張強さ(MPa) 」欄に示している。Tensile tests were performed at room temperature and 800 ° C. for each of the two types of heat treatment, and measured by the ASTM method at a parallel part diameter of 6.35 mm and an elongation of 4D. The tensile strength is shown in the column of "Tensile strength (MPa)" in Table 3.
【００５４】また、長時間加熱処理( 過時効処理) は、
従来熱処理材、固溶化熱処理なし材の各々について時効
処理後、800 ℃×400 時間後空冷の処理を行った。実際
のバルブの性能評価を模擬する試験として、回転曲げ疲
労試験を行った。回転曲げ疲労試験は、一定の曲げモー
メントを試料に与えた状態で試料を回転させる試験であ
る。試料は、平行部径8mm で行ない、条件は、回転数35
00rpm 、R=-1、試験温度800 ℃で245MPaの応力をかけた
際の破断回数により、高温強度を評価した。衝撃値につ
いては、U ノッチ 形状の試料で行ない、試験温度20℃で3
回測定して平均を求めた。ミクロ観察については、縦断
面のD/4 部について行った。また、高温長時間加熱処理
後の析出相の面積率測定は、走査型電子顕微鏡(SEM) を
用いて2500倍の倍率で三視野観察し、それを写真撮影
後、画像解析を行って測定した。The long-time heat treatment (overage treatment)
The conventional heat-treated material and the material without solution heat treatment were each aged and then air-cooled after 800 ° C for 400 hours. A rotary bending fatigue test was performed as a test simulating the performance evaluation of an actual valve. The rotating bending fatigue test is a test in which a sample is rotated while a constant bending moment is applied to the sample. The sample was prepared with a parallel part diameter of 8 mm.
High temperature strength was evaluated by the number of breaks when a stress of 245 MPa was applied at 00 rpm, R = -1, and a test temperature of 800 ° C. The impact value was measured on a U-notched sample at a test temperature of 20 ° C.
The measurement was repeated and the average was determined. Micro observation was performed on the D / 4 part of the longitudinal section. In addition, the area ratio of the precipitated phase after high-temperature and long-time heat treatment was measured using a scanning electron microscope (SEM) by observing three fields of view at a magnification of 2500 times, taking a picture of it, and performing image analysis. .
【００５５】[0055]
【表１】 [Table 1]
【００５６】[0056]
【表２】 [Table 2]
【００５７】[0057]
【表３】 [Table 3]
【００５８】表１と２のNo.1〜14は発明合金、No.15 〜
18は比較合金で、No.15 はNi量が本発明の範囲内から少
ない側に外れている合金、No.16 はCrならびにB 値が本
発明の範囲より多い合金、No.17 は、A 値が小さくTi量
が高く本発明の組成範囲から外れている合金、No.18 は
特開平7-109539号に開示された組成範囲の合金で本発明
の合金と比較して、Ni量が高い合金である。また、表２
のA 値、B 値はそれぞれ原子% で表される下記に示され
る値でる。In Tables 1 and 2, Nos. 1 to 14 are invention alloys and Nos. 15 to
No. 18 is a comparative alloy, No. 15 is an alloy in which the amount of Ni is out of the range of the present invention, No. 16 is an alloy in which the Cr and B values are higher than those of the present invention, and No. 17 is A No. 18 is an alloy having a small Ti value and a high Ti content and deviating from the composition range of the present invention, compared with the alloy of the present invention in an alloy having a composition range disclosed in Japanese Patent Application Laid-Open No. Alloy. Table 2
The A value and B value of are the values shown below expressed in atomic%, respectively.
【００５９】 A 値＝[Al]/([Al]+[Ti]+[Zr]+[Hf]+[V]+[Nb]+[Ta]) B 値＝([Cr]+[Mo]+[W])/([Ni]+[Co]+[Fe]+[Cr]+[Mo]+
[W]) 表３に示すように、冷間加工性については、比較合金の
No.16 合金はCr量を、No.17 合金はTiを多く含有するた
めに変形抵抗(70%加工時真応力) が高く冷間加工性が悪
い。また、No.18 合金は、特開平7-109539号に開示され
ているものであるが、Ni量を多く含有するため、本発明
合金と比較すると変形抵抗が高く冷間加工性が十分でな
い。A value = [Al] / ([Al] + [Ti] + [Zr] + [Hf] + [V] + [Nb] + [Ta]) B value = ([Cr] + [Mo] + [W]) / ([Ni] + [Co] + [Fe] + [Cr] + [Mo] +
[W]) As shown in Table 3, the cold workability of the comparative alloy
The No. 16 alloy contains a large amount of Cr and the No. 17 alloy has a large amount of Ti, so that it has high deformation resistance (true stress at 70% processing) and poor cold workability. No. 18 alloy is disclosed in Japanese Patent Application Laid-Open No. 7-109539. However, since the alloy contains a large amount of Ni, it has higher deformation resistance and insufficient cold workability as compared with the alloy of the present invention.
【００６０】以上のことから、固溶元素を本発明合金の
範囲より多量に添加すると、合金の変形抵抗が上昇し、
冷間加工性が低下する危険性がある。From the above, when the solid solution element is added in a larger amount than the range of the alloy of the present invention, the deformation resistance of the alloy increases,
There is a risk that the cold workability is reduced.
【００６１】しかし、その一方で、冷間加工性の向上を
目的として、Ni量を減少させると(No.15合金) 、マトリ
ックスの高温強度が低下するため、疲労強度や引張強度
が低下する。However, on the other hand, when the amount of Ni is reduced (No. 15 alloy) for the purpose of improving the cold workability, the high-temperature strength of the matrix is reduced, so that the fatigue strength and the tensile strength are reduced.
【００６２】以上のことから、Niを始めとする添加合金
元素の量をいたずらに多すぎても少なすぎても両方の特
性を同時に満足することは出来ない。本発明合金(No.1
〜14) は、この点を踏まえて、Niを始めとする合金元素
量を最適化し、強度と冷間加工性を両立させたものであ
る。本発明合金は、いずれも良好な冷間加工性、引張強
度、疲労強度及び高靭性( 衝撃値) を示している。From the above, both characteristics cannot be satisfied at the same time if the amounts of alloying elements, such as Ni, are too large or too small. Invention alloy (No. 1
Based on this point, Nos. 14 to 14) optimize the amounts of alloying elements including Ni and achieve both strength and cold workability. The alloys of the present invention all show good cold workability, tensile strength, fatigue strength and high toughness (impact value).
【００６３】ただ、発明合金の中でもγ' 相を形成する
A 値が高めのNo.9や14合金はγ' 相そのものの強度が高
くないために、本発明合金の中では、強度の上昇があま
り期待出来ない。A 値は本発明の範囲より小さくても、
大きくても、疲労強度を十分に満足することが出来な
い。However, among the alloys of the invention, a γ 'phase is formed.
No. 9 and No. 14 alloys with higher A values do not have high strength of the γ 'phase itself, so that the alloy of the present invention cannot be expected to increase in strength very much. Even if the A value is smaller than the range of the present invention,
Even if it is large, the fatigue strength cannot be sufficiently satisfied.
【００６４】例えば、疲労強度においては、比較合金で
あるNo.17 合金はA 値が低く、Ti量が高いために、長時
間加熱処理後に強度に寄与しないη相が多量に析出する
ので、他の合金と比較すると、疲労強度の上昇があまり
期待出来ない。For example, regarding the fatigue strength, the comparative alloy No. 17 alloy has a low A value and a high Ti content, so that a large amount of η phase which does not contribute to the strength is precipitated after a long-time heat treatment. No increase in fatigue strength can be expected as compared to the alloy of No.
【００６５】更に、比較合金であるA 値及びTi量が本発
明の範囲から外れる合金No.17 やB値が成分範囲内から
外れるNo.16 は、η相やσ相が析出するために、靭性の
指標となる衝撃値が大きく低下する。Further, the comparative alloy No. 17 in which the A value and the Ti content are out of the range of the present invention and No. 16 in which the B value is out of the component range, the η phase and the σ phase are precipitated. The impact value as an index of toughness is greatly reduced.
【００６６】したがって、上記の元素量の最適化同様
に、更に疲労強度や衝撃値に対しては、A 値やB 値によ
って特性が大きく低下する危険性があるので、A 値、B
値についても厳密に制御する必要がある。Therefore, similarly to the optimization of the element amounts described above, there is a risk that the characteristics of the fatigue strength and the impact value are greatly reduced by the A value and the B value.
The values also need to be strictly controlled.
【００６７】また、本発明合金において、固溶化熱処理
なし( 直接時効処理) 材は、従来熱処理材と比較して、
時効処理後の引張強さが高く、過時効処理後の疲労強度
( 疲労寿命) 、衝撃値が若干低下する傾向があるが、い
ずれの合金も良好な特性を示しており、本発明合金は、
固溶化熱処理を省略しても十分な特性を有していること
が分かる。In the alloy of the present invention, the material without the solution heat treatment (direct aging treatment) is compared with the conventional heat treated material.
High tensile strength after aging treatment, fatigue strength after overaging treatment
(Fatigue life), the impact value tends to decrease slightly, but all alloys show good characteristics, the alloy of the present invention,
It can be seen that even if the solution heat treatment is omitted, it has sufficient characteristics.
【００６８】以上説明したように、本発明合金は、エン
ジンバルブの性能として必要である従来合金とほぼ同等
の靭性や機械的性質を有しながら、従来合金よりも良好
な冷間加工性を具備した合金であることが分かる。As explained above, the alloy of the present invention has almost the same toughness and mechanical properties as the conventional alloy necessary for the performance of the engine valve, but has better cold workability than the conventional alloy. It can be seen that the alloy was made.
【００６９】[0069]
【発明の効果】本発明のエンジンバルブ用Fe基耐熱合金
は、固溶化処理後の硬さを低減して冷間加工性を飛躍的
に改善することができ、冷間鍛造可能でかつ高温での組
織安定性及び高温疲労強度に優れたエンジンバルブ材を
製造することが可能となり、エンジンバルブ製造コスト
を格段に低減させることができる。The Fe-base heat-resistant alloy for an engine valve according to the present invention can significantly improve cold workability by reducing the hardness after solution treatment, and can be cold forged at high temperatures. This makes it possible to manufacture an engine valve material having excellent structural stability and high-temperature fatigue strength, thereby significantly reducing engine valve manufacturing costs.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 佐藤 光司 島根県安来市安来町2107番地２ 日立金属 株式会社冶金研究所内 (72)発明者 大野 丈博 島根県安来市安来町2107番地２ 日立金属 株式会社安来工場内 (72)発明者 佐藤 克明 埼玉県和光市中央一丁目４番１号 株式会 社本田技術研究所内 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Koji Sato 2107-2 Yasugi-cho, Yasugi-shi, Shimane Hitachi Metals Research Institute, Ltd. (72) Inventor Takehiro Ohno 2107-2 Yasugi-cho, Yasugi-shi, Shimane Hitachi Metals, Ltd. Yasugi Plant (72) Inventor Katsuaki Sato 1-4-1, Chuo, Wako-shi, Saitama Pref.
Claims (10)
1.0以下、Ni及び3.0以下(0% を含む) のCoを合計で25を
超え30未満、Cr:10 〜18、Al:1.2〜2.5 、Ti:1.5〜3.0
を含み、IVa 族と Va 族から選ばれる一種または二種以
上の元素を合計で1.5 〜6.0 とを含み、残部は不純物を
除き実質的にFeからなることを特徴とする良好な冷間加
工性及び高温強度を具備したエンジンバルブ用Fe基耐熱
合金。C: 0.08 or less, Si: 1.0 or less, Mn:
1.0 or less, Ni and 3.0 or less (including 0%) Co exceeding 25 and less than 30 in total, Cr: 10-18, Al: 1.2-2.5, Ti: 1.5-3.0
Good cold workability characterized in that one or two or more elements selected from the group IVa and the group Va are contained in a total amount of 1.5 to 6.0, and the balance is substantially made of Fe excluding impurities. And Fe-base heat-resistant alloy for engine valves with high temperature strength.
0.5以下、Ni及び3.0以下(0% を含む) のCoを合計で26.5
〜28.5、Cr:12 〜16、Al:1.2〜2.5 、Ti:1.5〜3.0 、N
b:0.2〜2.0 を含み、残部は不純物を除き実質的にFeか
らなることを特徴とする請求項１に記載の良好な冷間加
工性及び高温強度を具備したエンジンバルブ用Fe基耐熱
合金。2. C: 0.05 or less, Si: 0.5 or less, Mn:
0.5 or less, Ni and 3.0 or less (including 0%) Co in total 26.5
~ 28.5, Cr: 12 ~ 16, Al: 1.2 ~ 2.5, Ti: 1.5 ~ 3.0, N
2. The Fe-base heat-resistant alloy for engine valves having good cold workability and high-temperature strength according to claim 1, wherein b: 0.2 to 2.0, with the balance being substantially Fe except for impurities.
たは二種を含むことを特徴とする請求項１または２に記
載の良好な冷間加工性及び高温強度を具備したエンジン
バルブ用Fe基耐熱合金。3. Good cold workability and high-temperature strength according to claim 1 or 2, comprising one or two of Mo: 3% or less and W: 3% or less by weight%. Fe-base heat-resistant alloy for engine valves.
特徴とする請求項１乃至３の何れかに記載の良好な冷間
加工性及び高温強度を具備したエンジンバルブ用Fe基耐
熱合金。4. The Fe-base heat-resistant engine valve having good cold workability and high temperature strength according to claim 1, wherein the Fe-containing heat-resistant material contains 0.015% or less by weight of B 2. alloy.
徴とする請求項１乃至４の何れかに記載の良好な冷間加
工性及び高温強度を具備したエンジンバルブ用Fe基耐熱
合金。 0.50≦[Al]/([Al]+[Ti]+[Zr]+[Hf]+[V]+[Nb]+[Ta])≦0.
605. The Fe-base heat-resistant alloy for an engine valve having good cold workability and high-temperature strength according to claim 1, wherein the following relational expression is satisfied in atomic%. 0.50 ≦ [Al] / ([Al] + [Ti] + [Zr] + [Hf] + [V] + [Nb] + [Ta]) ≦ 0.
60
徴とする請求項１乃至４の何れかに記載の良好な冷間加
工性及び高温強度を具備したエンジンバルブ用Fe基耐熱
合金。 0.14≦([Cr]+[Mo]+[W])/([Ni]+[Co]+[Fe]+[Cr]+[Mo]+
[W])≦0.206. The Fe-base heat-resistant alloy for engine valves having good cold workability and high-temperature strength according to claim 1, wherein the following relational expression is satisfied in atomic%. 0.14 ≦ ([Cr] + [Mo] + [W]) / ([Ni] + [Co] + [Fe] + [Cr] + [Mo] +
[W]) ≦ 0.20
のCaの一種または二種を含むことを特徴とする請求項１
乃至６の何れかに記載の良好な冷間加工性及び高温強度
を具備したエンジンバルブ用Fe基耐熱合金。7. The method according to claim 1, wherein one or two of Mg and 0.02% of Ca are contained in a percentage by weight of 0.02% or less.
7. An Fe-based heat-resistant alloy for an engine valve having good cold workability and high-temperature strength according to any one of claims 1 to 6.
のREM の一種または二種を含むことを特徴とする請求項
１乃至７の何れかに記載の良好な冷間加工性及び高温強
度を具備したエンジンバルブ用Fe基耐熱合金。8. The good cold workability and good cold workability according to claim 1, comprising one or two kinds of Y in less than 0.01% and REM in less than 0.01% by weight. Fe-based heat-resistant alloy for engine valves with high-temperature strength.
0 時間加熱後の800℃-245MPa で回転曲げ疲労試験を行
った際の破断回数が1.0 ×106 回以上であることを特徴
とする請求項１乃至８の何れかに記載の良好な冷間加工
性及び高温強度を具備したエンジンバルブ用Fe基耐熱合
金。9. 60% to 80% at 800 ° C. after cold working at 40 ° C.
The good cold according to any one of claims 1 to 8, wherein the number of fractures in a rotational bending fatigue test at 800 ° C-245MPa after heating for 0 hour is 1.0 × 10 6 times or more. Fe-base heat-resistant alloy for engine valves with workability and high-temperature strength.
を1800MPa 以下であることを特徴とする請求項１乃至９
の何れかに記載の良好な冷間加工性及び高温強度を具備
したエンジンバルブ用Fe基耐熱合金。10. The method according to claim 1, wherein a true stress required for performing 70% cold working is 1800 MPa or less.
13. An Fe-base heat-resistant alloy for an engine valve having good cold workability and high-temperature strength according to any one of the above.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP35677899A JP4057208B2 (en) | 1999-12-16 | 1999-12-16 | Fe-base heat-resistant alloy for engine valves with good cold workability and high-temperature strength |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP35677899A JP4057208B2 (en) | 1999-12-16 | 1999-12-16 | Fe-base heat-resistant alloy for engine valves with good cold workability and high-temperature strength |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2001172751A true JP2001172751A (en) | 2001-06-26 |
| JP4057208B2 JP4057208B2 (en) | 2008-03-05 |
Family
ID=18450728
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP35677899A Expired - Fee Related JP4057208B2 (en) | 1999-12-16 | 1999-12-16 | Fe-base heat-resistant alloy for engine valves with good cold workability and high-temperature strength |
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| Country | Link |
|---|---|
| JP (1) | JP4057208B2 (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7651575B2 (en) | 2006-07-07 | 2010-01-26 | Eaton Corporation | Wear resistant high temperature alloy |
| JP2015030873A (en) * | 2013-08-01 | 2015-02-16 | 株式会社東芝 | Austenitic heat resistant steel and turbine component |
| JP2015183256A (en) * | 2014-03-25 | 2015-10-22 | 株式会社東芝 | Austenitic heat resistant steel and turbine component |
| EP3795272A1 (en) | 2019-09-20 | 2021-03-24 | Hitachi Metals, Ltd. | Nut-shaped fcc magnet and method for manufacturing the same |
| CN116904724A (en) * | 2023-07-12 | 2023-10-20 | 舟山市7412工厂 | Bolt and heat treatment process thereof |
-
1999
- 1999-12-16 JP JP35677899A patent/JP4057208B2/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7651575B2 (en) | 2006-07-07 | 2010-01-26 | Eaton Corporation | Wear resistant high temperature alloy |
| JP2015030873A (en) * | 2013-08-01 | 2015-02-16 | 株式会社東芝 | Austenitic heat resistant steel and turbine component |
| JP2015183256A (en) * | 2014-03-25 | 2015-10-22 | 株式会社東芝 | Austenitic heat resistant steel and turbine component |
| EP3795272A1 (en) | 2019-09-20 | 2021-03-24 | Hitachi Metals, Ltd. | Nut-shaped fcc magnet and method for manufacturing the same |
| CN116904724A (en) * | 2023-07-12 | 2023-10-20 | 舟山市7412工厂 | Bolt and heat treatment process thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| JP4057208B2 (en) | 2008-03-05 |
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