JP2567258B2 - Iron-based casting having high strength, high rigidity, and high toughness, and a method for producing the same - Google Patents
Iron-based casting having high strength, high rigidity, and high toughness, and a method for producing the sameInfo
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- JP2567258B2 JP2567258B2 JP62265900A JP26590087A JP2567258B2 JP 2567258 B2 JP2567258 B2 JP 2567258B2 JP 62265900 A JP62265900 A JP 62265900A JP 26590087 A JP26590087 A JP 26590087A JP 2567258 B2 JP2567258 B2 JP 2567258B2
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- iron
- toughness
- rigidity
- strength
- graphite
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- Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
Description
【発明の詳細な説明】 産業上の利用分野 本発明は、高強度、高剛性、高靭性を有する鉄系鋳物
およびその製造法に関するものであり、とくに、自動車
のクランクシャフト、コンロッド、カムシャフトなどの
部品用材料に適した、鋳造性が良好で、高強度、高剛
性、高靭性を有する鉄系鋳物およびその製造法に関する
ものである。Description: TECHNICAL FIELD The present invention relates to an iron-based casting having high strength, high rigidity, and high toughness and a method for producing the same, and in particular, an automobile crankshaft, connecting rod, camshaft, and the like. The present invention relates to an iron-based casting having good castability, high strength, high rigidity, and high toughness, which is suitable as a material for parts, and a manufacturing method thereof.
先行技術 近年、自動車用部品においては、軽量化のニーズか
ら、材料の高強度化が、また、振動、騒音対策の面か
ら、材料の高剛性化が、それぞれ求められている。2. Description of the Related Art In recent years, in automobile parts, there has been a demand for higher strength of materials due to the need for weight reduction, and higher rigidity for materials in terms of measures against vibration and noise.
今日、自動車用部品として多く用いられている球状黒
鉛鋳鉄は、優れた鋳造性を有し、また、オーステンパー
処理などによって高強度化が図られているが、この球状
黒鉛鋳鉄は、通常、2.5重量％以上の炭素を含んでいる
ため、弾性係数が低く、剛性の面で劣るという問題があ
った。また、鋳鋼は、強度、剛性面で優れているが、製
造がしにくく、加工性に劣るという欠点があった。Today, spheroidal graphite cast iron, which is often used as automobile parts, has excellent castability, and high strength is achieved by austempering and the like. Since it contains carbon by weight or more, there is a problem that the elastic modulus is low and the rigidity is poor. Further, cast steel is excellent in strength and rigidity, but has a drawback that it is difficult to manufacture and is inferior in workability.
このような状況下で、特開昭61-174358号公報は、Fe
−Ｃ−Si系の過共析組成を有し、マグネシウム、カルシ
ウム、セリウムなどの球状化元素を加えることにより球
状化した黒鉛とベイナイト組織からなる低炭素の球状黒
鉛鋳鉄を提案している。Under such circumstances, JP-A-61-174358 discloses that Fe
A low-carbon spheroidal graphite cast iron having a -C-Si-based hypereutectoid composition and composed of graphite spheroidized by adding a spheroidizing element such as magnesium, calcium, or cerium and a bainite structure is proposed.
発明の解決しようとする問題点 しかしながら、このようにマグネシウム、カルシウ
ム、セリウムなどの球状化元素を加えることにより黒鉛
の球状化を図るときは、球状化処理時に激しい反応や温
度低下が生じて、歩留まりが悪く、また製造上の管理が
困難であるだけでなく、球状黒鉛が微細化しにくく、疲
労強度に劣るなど、自動車のクランクシャフト、コンロ
ッド、カムシャフトなどの部品に使用するには、十分な
強度が得られないという問題があった。Problems to be Solved by the Invention However, when spheroidizing graphite by adding spheroidizing elements such as magnesium, calcium, and cerium in this way, a vigorous reaction and temperature decrease occur during the spheroidizing treatment, and the yield Is not only difficult to manage and is difficult to control in manufacturing, but it is difficult to make spheroidal graphite fine and has poor fatigue strength, so it has sufficient strength to be used for parts such as automobile crankshafts, connecting rods, and camshafts. There was a problem that could not be obtained.
また、自動車のクランクシャフトやコンロッド、サス
ペンションのナックル部などの部材には、エンジンの運
転中に、引張りおよび圧縮荷重やねじり荷重が繰り返し
加わるため、クラックなどの発生を防止する上で、靭性
を向上させて疲労強度を高めることが必要であるが、十
分な強度、剛性を備え、かつ、高靭性を有する鉄系鋳物
は、得られていなかった。In addition, tensile, compressive, and torsional loads are repeatedly applied to parts such as automobile crankshafts, connecting rods, and knuckles of suspensions while the engine is running, improving crack toughness and preventing cracks. Although it is necessary to increase the fatigue strength by doing so, an iron-based casting having sufficient strength and rigidity and high toughness has not been obtained.
発明の目的 本発明は、鋳造性が良好で、高強度、高剛性、高靭性
を有する鉄系鋳物およびその製造法を提供することを目
的とするものである。OBJECT OF THE INVENTION It is an object of the present invention to provide an iron-based casting having good castability, high strength, high rigidity, and high toughness, and a method for producing the same.
本発明の別の目的は、自動車のクランクシャフト、コ
ンロッド、カムシャフトなどの部品用材料に適した、鋳
造性が良好で、高強度、高剛性、高靭性を有する鉄系鋳
物およびその製造法を提供することにある。Another object of the present invention is to provide an iron-based casting having good castability, high strength, high rigidity, and high toughness, which is suitable for materials for parts such as automobile crankshafts, connecting rods, and camshafts, and a manufacturing method thereof. To provide.
発明の構成 本発明のかかる目的は、0.5〜2.5重量％の炭素、1.0
〜4.0重量％の珪素、0.6重量％以下のマンガン、0.05重
量％以下のイオウ、0.01〜0.1重量％の硼素を含み、オ
ーステンパー処理によって、基地をベイナイトと残留オ
ーステナイトとの混在組織とし、球状黒鉛が分散した組
織とすることによって達成される。DETAILED DESCRIPTION OF THE INVENTION Such an object of the present invention is to provide 0.5 to 2.5% by weight of carbon,
~ 4.0 wt% silicon, 0.6 wt% or less manganese, 0.05 wt% or less sulfur, 0.01 ~ 0.1 wt% boron, by the austempering process, the matrix to a mixed structure of bainite and residual austenite, spherical graphite It is achieved by having a distributed organization.
本発明において、オーステンパー処理は、通常のオー
ステンパー処理と同様に、オーステナイト化処理と恒温
変態処理とからなり、これにより、基地をベイナイトと
残留オーステナイトとの混在組織とするためのものであ
る。オーステナイト化処理は、830〜980℃で５〜120分
間、鋳物素材を保持したのち、恒温変態処理温度に保っ
たソルト浴などに浸漬しておこなうことが好ましい。オ
ーステナイト化処理保持温度が、830℃未満では、均
一、安定なオーステナイト化が達成されないため、所望
の強度、靭性を得ることができず、他方、980℃を越え
ると、結晶粒が粗大化し、靭性および延性を低下させて
しまう。また、オーステナイト化保持時間が、５分未満
では、所望のオーステナイト化が実現できず、他方、12
0分を越えても、意味がない。オーステナイト化処理
は、電気炉などで直接加熱保持する方法によってもよ
い。また、恒温変態処理は、オーステナイト化された鋳
物素材を、ソルト浴などで、230〜450℃の温度で、30〜
180分間、恒温保持することによっておこなうことが望
ましい。230℃未満では、マルテンサイトを多量に形成
してしまい、所望の基地組織を得ることができず、他
方、450℃を越えると、パーライト組織が生じ、靭性の
低下を招いてしまう。また、保持時間が、30分未満で
は、多量の不安定なオーステナイトが残留し、空冷の過
程で、マルテンサイトが生成して、靭性が低下するし、
他方、180℃を越えると、残留オーステナイトの分解が
促進され、炭化物の析出が生じてしまう。In the present invention, the austempering treatment comprises an austenitizing treatment and a constant temperature transformation treatment as in the case of the ordinary austempering treatment, whereby the matrix has a mixed structure of bainite and retained austenite. The austenitizing treatment is preferably carried out by holding the casting material at 830 to 980 ° C. for 5 to 120 minutes and then immersing it in a salt bath kept at a constant temperature transformation treatment temperature. If the holding temperature for austenitizing treatment is less than 830 ° C, uniform and stable austenitizing cannot be achieved, so desired strength and toughness cannot be obtained. On the other hand, if it exceeds 980 ° C, the crystal grains become coarse and toughness increases. And ductility will be reduced. Further, if the austenitizing holding time is less than 5 minutes, the desired austenitizing cannot be realized, while
There is no point in exceeding 0 minutes. The austenitizing treatment may be carried out by directly heating and holding it in an electric furnace or the like. In addition, the isothermal transformation treatment is carried out by casting the austenitized casting material in a salt bath at a temperature of 230 to 450 ° C for 30 to
It is desirable to do this by keeping the temperature constant for 180 minutes. If it is lower than 230 ° C, a large amount of martensite is formed and a desired matrix structure cannot be obtained. On the other hand, if it is higher than 450 ° C, a pearlite structure is generated and toughness is deteriorated. Further, when the holding time is less than 30 minutes, a large amount of unstable austenite remains, martensite is generated in the process of air cooling, and the toughness decreases,
On the other hand, when the temperature exceeds 180 ° C., decomposition of retained austenite is promoted, and carbide is precipitated.
本発明において、炭素は、珪素とともに、黒鉛の生成
を促進する元素である。炭素の含有量が、0.5重量％未
満では、鋳造性、とくに、流動性および引け性が悪化す
るとともに黒鉛の生成が少なく、炭化物が多く析出し、
延性が低くなってしまう。他方、2.5重量％を越える
と、黒鉛の析出が多くなりすぎ、強度が低下するととも
に弾性係数が低下して、剛性を十分高めることができな
くなる。In the present invention, carbon is an element that promotes the formation of graphite together with silicon. If the carbon content is less than 0.5% by weight, castability, especially fluidity and shrinkage will deteriorate, and the production of graphite will be small, and a large amount of carbide will be precipitated.
The ductility will be low. On the other hand, if it exceeds 2.5% by weight, the precipitation of graphite becomes too much, the strength is lowered and the elastic modulus is lowered, and the rigidity cannot be sufficiently enhanced.
本発明において、珪素は、黒鉛の生成を促進する元素
であり、この含有量が、1.0重量％未満では、黒鉛の生
成が少なく、炭化物が多く析出すにとともに、鋳造性が
著しく悪化し、他方、3.0重量％を越えると、黒鉛、フ
エライトが多く析出し、強度および剛性が低下してしま
う。In the present invention, silicon is an element that promotes the formation of graphite, and when the content is less than 1.0% by weight, the production of graphite is small, and a large amount of carbide is precipitated, and the castability is significantly deteriorated. , 3.0% by weight, graphite and ferrite are precipitated in large amounts, resulting in deterioration of strength and rigidity.
本発明において、マンガンは、炭化物の生成を促進す
る元素であるが、この含有量が、0.6重量％を越える
と、黒鉛の生成が阻害され、また、不純物であるイオウ
と化合して、MnSを作り、黒鉛の球状化が不十分とな
り、延性も悪化させてしまうだけでなく、オーステンパ
ー処理した基地の組成の靭性を著しく低下させてしま
う。In the present invention, manganese is an element that promotes the formation of carbides, but if this content exceeds 0.6% by weight, the formation of graphite is inhibited, and it is combined with sulfur that is an impurity to form MnS. Not only does the spheroidization of graphite become insufficient and the ductility deteriorates, but also the toughness of the composition of the austempered matrix is significantly reduced.
本発明において、イオウは不純物であり、マンガンと
化合して、MnSを作り、黒鉛の球状化を悪化させるの
で、0.05重量％以下に抑えることが必要である。In the present invention, sulfur is an impurity and combines with manganese to form MnS and deteriorates the spheroidization of graphite. Therefore, it is necessary to suppress the content to 0.05% by weight or less.
本発明において、硼素は、黒鉛の球状化を促進させる
元素である。硼素を添加することにより、基地中に適度
な黒鉛核が生成し、鋳造性が著しく改善されるとともに
微細な球状黒鉛が組織中に分散され、強度が大幅に向上
する。硼素の含有量が、0.01重量％未満では、かかる効
果が十分でなく、また、0.1重量％を越えて添加して
も、かかる効果が飽和してしまうので、意味がない。In the present invention, boron is an element that promotes spheroidization of graphite. By adding boron, appropriate graphite nuclei are generated in the matrix, the castability is remarkably improved, and fine spheroidal graphite is dispersed in the structure, and the strength is significantly improved. If the content of boron is less than 0.01% by weight, such effect is not sufficient, and if it is added in excess of 0.1% by weight, the effect is saturated, so that it is meaningless.
本発明において、さらに、必要に応じて、ビスマス、
チタンおよびテルルのうち、少なくとも１種を、0.05重
量％以下、添加してもよい。硼素のみでは、黒鉛は比較
的粗大となるため、機械的性質が必ずしも十分でない場
合があるが、これらを添加すると、黒鉛のより一層の微
細化を図ることができ、好ましい。In the present invention, further, if necessary, bismuth,
At least one of titanium and tellurium may be added in an amount of 0.05% by weight or less. If only boron is used, graphite becomes relatively coarse, so that the mechanical properties may not always be sufficient. However, if these are added, graphite can be further miniaturized, which is preferable.
また、本発明において、さらに、鋳物素材の肉厚が厚
い場合などに、内部まで十分急冷されずにパーライト組
織などが生成されることを防止して、焼入れ性を向上さ
せるために、必要に応じ、銅、ニッケル、モリブデン、
バナジウムなどの元素を添加してもよい。これらの元素
の添加量は、0.05〜0.2重量％が好ましい。Further, in the present invention, when the casting material has a large wall thickness, etc., in order to prevent the formation of a pearlite structure or the like without being rapidly cooled sufficiently to the inside, and to improve the hardenability, as necessary. , Copper, nickel, molybdenum,
An element such as vanadium may be added. The addition amount of these elements is preferably 0.05 to 0.2% by weight.
実施例 以下、本発明の効果を、より一層明確にするため、実
施例を掲げる。Examples Examples will be given below to further clarify the effects of the present invention.
実施例 第１表に示す組成のJIS45,No.12に規定される試験片
サンプルを作り、機械的特性を調べた。サンプル＃１〜
５は、本発明の実施例にかかり、サンプル＃６、７は、
比較例である。第１表の化学組成中、りん（Ｐ）は、不
純物である。鋳型としては、200mm×20mm×40mmのＹ型
ブロック形状の鋳型で、サンプル＃１は、金型を用い、
その他のサンプルは、シエル型を用いた。また、溶解炉
としては、10kg高周波溶解炉を用いた。鋳造後、サンプ
ル＃６は、調質処理（焼入れ後、焼戻し処理）を施した
が、その他のサンプルについては、オーステンパー処理
をおこなった。オーステンパー処理は、サンプルを900
℃で、１時間30分、オーステナイト化処理をおこなった
のち、380℃で、１時間30分、ソルト浴に浸漬すること
によっておこなった。Example A test piece sample having the composition shown in Table 1 and defined in JIS45, No. 12 was prepared and its mechanical properties were investigated. Sample # 1
5 relates to the embodiment of the present invention, and Samples # 6 and 7 are
This is a comparative example. In the chemical composition shown in Table 1, phosphorus (P) is an impurity. The mold is a 200 mm × 20 mm × 40 mm Y-shaped block mold, and sample # 1 is a mold.
The other samples were shell type. As the melting furnace, a 10 kg high frequency melting furnace was used. After casting, sample # 6 was subjected to a tempering treatment (after quenching and tempering treatment), while the other samples were subjected to austempering treatment. Austempered 900 samples
After performing an austenitizing treatment at 1 ° C. for 1 hour and 30 minutes, it was performed by immersing in a salt bath at 380 ° C. for 1 hour and 30 minutes.
こうして得られた本発明の実施例にかかるサンプル＃
１〜５は、いずれも、残留オーステナイトとベイナイト
の混在した基地組織に球状黒鉛が分散した組織を形成し
ていた。第１図に、サンプル＃１の組織を示す写真が示
されている。第１図の写真において、黒い円形の部分は
球状黒鉛を、灰色の部分はベイナイトを、また、その他
の白い部分は残留オーステナイトを、それぞれ、示して
いる。 Sample # according to Example of the present invention thus obtained
In all of Nos. 1 to 5, a structure in which spheroidal graphite was dispersed in a matrix structure in which retained austenite and bainite were mixed was formed. A photograph showing the structure of Sample # 1 is shown in FIG. In the photograph of FIG. 1, the black circular portion indicates spheroidal graphite, the gray portion indicates bainite, and the other white portions indicate retained austenite.
また、第２表には、これらのサンプルの機械的性質を
測定した結果が示されている。In addition, Table 2 shows the results of measuring the mechanical properties of these samples.
第２表中、硬さHvは、ビッカーズ硬度を示す。第２表
より明らかなように、本発明の実施例であるサンプル＃
１〜５は、いずれも所望以上の引張り強度、ヤング率
（剛性を示す）、硬さを備え、また、靭性を示す伸びも
所望以上であることがわかった。これに対し、比較例で
あるサンプル＃６は、剛性、靭性は所望以上であるもの
の、引張り強度および硬さが十分でなく、また、＃７
は、靭性および硬さは所望以上であるものの、引張り強
度および剛性が劣っていることがわかった。さらに、サ
ンプル＃６は、鋳鋼であり、鋳造性も悪かった。 In Table 2, hardness Hv indicates Vickers hardness. As is clear from Table 2, sample # which is an embodiment of the present invention
It was found that all of 1 to 5 have tensile strength, Young's modulus (indicative of rigidity) and hardness that are higher than desired, and that elongation that indicates toughness is also higher than desired. On the other hand, Sample # 6, which is a comparative example, has rigidity and toughness that are higher than desired, but has insufficient tensile strength and hardness.
Was found to have poor toughness and hardness, but poor tensile strength and rigidity. Further, Sample # 6 was cast steel and had poor castability.
以上の実施例より、本発明にかかる鉄系鋳鉄は、高強
度、高剛性および高靭性という要求を同時に満足するも
のであることが判明した。From the above examples, it was found that the iron-based cast iron according to the present invention simultaneously satisfies the requirements of high strength, high rigidity and high toughness.
本発明は、以上の実施例に限定されることなく特許請
求の範囲に記載された発明の範囲内で種々の変更が可能
であり、それらも本発明の範囲内に包含されるものであ
ることはいうまでもない。The present invention is not limited to the above embodiments, and various modifications can be made within the scope of the invention described in the claims, and those modifications are also included in the scope of the present invention. Needless to say.
発明の効果 本発明によれば、製造が容易で、高強度、高剛性、高
靭性を有する鉄系鋳物を得ることが可能となり、軽量
で、かつ高い強度、剛性および靭性が同時に要求される
自動車のクランクシャフト、コンロッド、カムシャフト
などの部品に適した鉄系鋳物を容易に得ることが可能と
なる。EFFECTS OF THE INVENTION According to the present invention, it is possible to obtain an iron-based casting that is easy to manufacture, has high strength, high rigidity, and high toughness, is lightweight, and is simultaneously required to have high strength, rigidity, and toughness. It is possible to easily obtain iron-based castings suitable for parts such as crankshafts, connecting rods, and camshafts.
【図面の簡単な説明】 第１図は実施例におけるサンプル＃１の組織を示す写真
である。BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a photograph showing the structure of Sample # 1 in the examples.
Claims (2)
珪素、0.6重量％以下のマンガン、0.05重量％以下のイ
オウ、0.01〜0.1重量％の硼素を含み、オーステンパー
処理により、基地がベイナイトと残留オーステナイトと
の混在組織からなり、球状黒鉛が分散していることを特
徴とする高強度、高剛性、高靭性を有する鉄系鋳物。1. Containing 0.5 to 2.5 wt% carbon, 1.0 to 4.0 wt% silicon, 0.6 wt% or less manganese, 0.05 wt% or less sulfur, and 0.01 to 0.1 wt% boron, and by austempering treatment, An iron-based casting having high strength, high rigidity, and high toughness, characterized in that the matrix has a mixed structure of bainite and retained austenite and spheroidal graphite is dispersed.
珪素、0.6重量％以下のマンガン、0.05重量％以下のイ
オウ、0.01〜0.1重量％の硼素を含む鉄系鋳物素材をオ
ーステンパー処理し、基地をベイナイトと残留オーステ
ナイトとの混在組織とし、球状黒鉛を分散させたことを
特徴とする高強度、高剛性、高靭性を有する鉄系鋳物の
製造法。2. An iron-based casting material containing 0.5 to 2.5 wt% carbon, 1.0 to 4.0 wt% silicon, 0.6 wt% or less manganese, 0.05 wt% or less sulfur, and 0.01 to 0.1 wt% boron. A method for producing an iron-based casting having high strength, high rigidity, and high toughness, which is obtained by performing a tempering treatment to form a matrix having a mixed structure of bainite and retained austenite and dispersing spherical graphite.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62265900A JP2567258B2 (en) | 1987-10-21 | 1987-10-21 | Iron-based casting having high strength, high rigidity, and high toughness, and a method for producing the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62265900A JP2567258B2 (en) | 1987-10-21 | 1987-10-21 | Iron-based casting having high strength, high rigidity, and high toughness, and a method for producing the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01108342A JPH01108342A (en) | 1989-04-25 |
| JP2567258B2 true JP2567258B2 (en) | 1996-12-25 |
Family
ID=17423664
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62265900A Expired - Fee Related JP2567258B2 (en) | 1987-10-21 | 1987-10-21 | Iron-based casting having high strength, high rigidity, and high toughness, and a method for producing the same |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2567258B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5043028A (en) * | 1990-04-27 | 1991-08-27 | Applied Process | High silicon, low carbon austemperable cast iron |
| JP2803331B2 (en) * | 1990-06-21 | 1998-09-24 | トヨタ自動車株式会社 | Manufacturing method of high toughness cast steel |
| SE531107C2 (en) * | 2006-12-16 | 2008-12-23 | Indexator Ab | Method |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5754246A (en) * | 1980-09-13 | 1982-03-31 | Mazda Motor Corp | Spheroidal graphite cast iron of excellent machinability |
| JPS60110843A (en) * | 1983-11-18 | 1985-06-17 | Toyota Motor Corp | Spheroidal graphite cast iron for austempering |
| JPS61174358A (en) * | 1985-01-30 | 1986-08-06 | Toyota Motor Corp | Spheroidal graphite cast steel of high strength |
| JPS61177324A (en) * | 1985-01-04 | 1986-08-09 | ポンタ‐ムーソン・エス・アー | Method and apparatus for continuously producing spheroidizing graphite cast iron pipe |
-
1987
- 1987-10-21 JP JP62265900A patent/JP2567258B2/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5754246A (en) * | 1980-09-13 | 1982-03-31 | Mazda Motor Corp | Spheroidal graphite cast iron of excellent machinability |
| JPS60110843A (en) * | 1983-11-18 | 1985-06-17 | Toyota Motor Corp | Spheroidal graphite cast iron for austempering |
| JPS61177324A (en) * | 1985-01-04 | 1986-08-09 | ポンタ‐ムーソン・エス・アー | Method and apparatus for continuously producing spheroidizing graphite cast iron pipe |
| JPS61174358A (en) * | 1985-01-30 | 1986-08-06 | Toyota Motor Corp | Spheroidal graphite cast steel of high strength |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH01108342A (en) | 1989-04-25 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |