JP2716063B2 - Spheroidal graphite cast iron with excellent low temperature toughness - Google Patents
Spheroidal graphite cast iron with excellent low temperature toughnessInfo
- Publication number
- JP2716063B2 JP2716063B2 JP62323812A JP32381287A JP2716063B2 JP 2716063 B2 JP2716063 B2 JP 2716063B2 JP 62323812 A JP62323812 A JP 62323812A JP 32381287 A JP32381287 A JP 32381287A JP 2716063 B2 JP2716063 B2 JP 2716063B2
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- impact value
- low temperature
- elongation
- present
- cast iron
- Prior art date
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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
本発明は低温靭性にすぐれた球状黒鉛鋳鉄に関する。
従来技術
従来のフェライト地を有する球状黒鉛鋳鉄FCD37又はF
CD40は、伸び、衝撃値は高いが、引張強さが低く、パー
ライト地であるFCD50又はFCD60では引張強さや耐力は高
いが伸びや衝撃値、特に低温での衝撃値が低い。
これらを改善する為にNiを添加する方法が特公昭61−
33897号公報等によって開示されている。この発明では
−15℃で最低1.7kgf・m/cm2の衝撃値しか得られない。
また、C:0.3〜4.2％、Si:1.3〜2.2％、Ni:1〜５％、M
g:0.02〜0.08％と残部Fe及びMn、Cr、Sn、Ｖ、Mo、Cuな
どの不純物よりなる鋳放しパーライト地球状黒鉛鋳鉄が
特開昭和53−97918号として開示されている。このもの
は、同一製品内で均一なパーライトを得るために、フェ
ライト化促進元素であるSiを低い値に押え、パーライト
安定化のために、Ni（１〜５％）を含有させることによ
りSiを減少させるものである。
さらに、重量比で3.3〜4.4％のＣ、2.0〜3.5％のSi、
およびMg,Ca、稀土類元素の少なくとも１種を球状化に
十分な量含み、フェライト化阻害元素であるMnは0.15％
以下、Ｐは0.06％以下、Crは0.05％以下、Niは0.15％以
下、Cuは0.06％以下、Snは0.01％以下とし、残余が鉄か
らなる高純度銑鉄中にBiまたはTeの少なくとも１種を0.
005〜0.02％含有させて鋳造する厚肉フェライト型球状
黒鉛鋳鉄の製造方法が特公昭47−18337号に開示されて
いる。この方法は、Cr、Mnが極度に偏折する肉厚が50mm
以上の鋳物を対象としているものであり、この方法で
は、単にフェライト化することのみを追求しているため
Siが最大3.5％まで許容され、フェライト阻害元素であ
るNiは、単に低い方（0.15％以下）がよいとしている。
自動車用や産業用鋳物部品は最近さらに強靭性を要求
されかつ−40℃程度の低温下でも使用されることが多
く、このような低温でも高い衝撃値が要求されるように
なった。
そこで本発明者等は、Niを重量％で0.5〜1.0％未満添
加することにより伸びと共に−40℃程度の低温における
衝撃値を向上させた。
また上記発明ではフェライト組織であることを条件と
し実施例ではフェライト化焼なましを行なっているが、
製造原価を低減する意味では焼なましを行なわず、鋳放
し状態で使用することが最も好ましい。
また、微量のBiを添加することにより黒鉛粒数を300
ケ/mm2以上にすることによって、パーライトを減少さ
せ、熱処理をしなくても、又は熱処理をするとしても低
温でかつ短時間の熱処理で充分な伸びと衝撃値を確保す
る。
もちろん焼なましを行なってフェライト組織にすれ
ば、更に高い伸びや靭性が得られることはいうまでもな
い。
発明が解決しようとする課題
本発明の目的は、伸びと衝撃値、特に−40℃程度の低
温での衝撃値を向上せしめ、また必要に応じてBiを添加
することにより熱処理を省くか、行っても低温でかつ短
時間の熱処理を行うのみで製造原価を低減し得る球状黒
鉛鋳鉄を提供するものである。
課題を解決するための手段
本発明の低温靭性にすぐれた球状黒鉛鋳鉄は、
重量％でC:3.0 〜4.0％
Si:1.5 〜2.3％
Mn: ＜0.3％
P : ＜0.03％
Ni:0.5 〜1.0％未満
Cr: ＜0.10％
Mg:0.02〜0.06％
残余鉄及び不可避的不純物からなり、かつCE値が3.9〜
4.6％の溶湯を用いるか、必要に応じて上記組成の溶湯
に0.005〜0.03％のBiを添加し、該Bi添加と同時に又は
添加後に接種を行ない、黒鉛粒数を300ケ/mm2以上とし
たことを特徴とするものである。
Biの残留含有量は0.0015〜0.015％とするのがよい。
本発明において、CE値とはSiの重量％の３分の１とＣ
の重量％との和である。
次に、前記数値の限定理由について説明する。
Ｃは3.0％未満では鋳造性が悪くなり、かつ黒鉛粒数
が減少するためパーライトが多くなる。また4.0％を超
えるとキッシュ黒鉛が出やすくなり強度が低下する。
Siは1.5％未満では炭化物が析出しやすくなり衝撃値
と伸びが低下する。また2.3％を超えるとシリコフェラ
イトの影響で衝撃値や伸びが低下する。
Mnが0.3％を超えるとパーライトが多くなり衝撃値と
伸びが低下する。
Ｐは0.03％を超えるとステダイトの影響で衝撃値と伸
びが低下する。
Niは0.5％未満では強度が得られない。また、1.0％以
上であると特に低温（−40℃）での伸び、衝撃値が低下
する。
Crが0.1％を超えると炭化物が析出しやすくなり衝撃
値と伸びが低下する。
Mgは0.02％未満では黒鉛が球状化せず、0.06％を超え
ると、ひけ巣、炭化物が出やすくなるばかりでなく、経
済的にも不利となる。
CE値は3.9％未満では炭化物が出やすくなり、また鋳
造性も悪くなる。4.6％を超えるとキッシュ黒鉛が出や
すくなる。
Biはその残留含有量が0.0015％未満では黒鉛粒数増大
効果が低下し、そのため鋳放し組織中にセメンタイトが
発生するようになる。
また残留含有量が0.0150％を超えるとBiの黒鉛球状化
阻害効果が現出し、黒鉛の球状化率が70％以下となって
機械的諸性質が劣化する。
Biは球状黒鉛鋳鉄溶湯に対する溶け込み歩留まり率が
悪く、しかも変動も大きいため、その残留含有量を0.00
15〜0.0150％にするためには添加量として0.005〜0.030
％に設定する必要がある。
黒鉛粒数は、300ケ/mm2未満では、黒鉛間距離が大き
くなりパーライトの析出が多くなって衝撃値、伸びが低
下する。
〔作 用〕
本発明は、引張強さ、耐力が高く、かつ伸び、衝撃
値、特に−40℃での衝撃値の高い球状黒鉛鋳鉄が鋳放し
でも得ることができる。
またフェライト化焼なまし熱処理を行なえば、更に高
い衝撃値、伸びが得られる。
〔実施例.1〕
１）化学成分
２）鋳 型
25mm厚さ×250mm長さのＹブロックの鋳型をCO2鋳型で
造型した。
３）結 果
上記鋳型に溶湯を注入して作成したテストピースにつ
いての調査結果を以下に記す。
第１図（ａ），（ｂ），（ｃ），（ｄ），（ｅ）に顕
微鏡組織を示す。本発明材は第１図（ａ）であり、第１
図（ｂ），（ｃ）はそれぞれNiが1.05％、、1.98％であ
る比較材を示し、第１図（ｄ），（ｅ）それぞれ従来材
FCD40,FCD60を示すものである。
第２図、第３図に機械的性質を示す。本発明の0.53％
Ni材は、1.05％Ni比較材に較べて引張強さ、耐力はやや
劣るものの、伸び、室温での衝撃値、低温（−40℃）で
の衝撃値は高い値を示している。また、本発明の0.53％
Ni材は、1.98％Ni比較材に較べて引張強さ、耐力はやや
劣るものの、伸び、室温での衝撃値、低温（−40℃）で
の衝撃値は高い値を示し、特に低温（−40℃）での衝撃
値は２倍以上高い値を示している。
さらに、本発明の0.53％Ni材は引張強さ、耐力はFCD4
0に較べて同等であり、伸び、室温での衝撃値が高く、
特に低温（−40℃）での衝撃値は２倍以上高い値を示し
ている。また、本発明の0.53％Ni材は、FCD60材に較べ
ると引張強さ、耐力は低いが、第３図に示すように、伸
び、室温での衝撃値は優れており、特に低温（−40℃）
での衝撃値が格段に改善されている。
このように本発明材は、従来の材質に較べて特に低温
（−40℃）で極めて優れた材質であることがわかる。
〔実施例.2〕
１）化学成分
〔実施例.1〕と同じ。
２）熱処理
〔実施例.1〕で得られた素材（除FCD60）を次の熱処
理サイクルにてフェライト化焼なましを行った。
900℃×２時間→720℃×２時間→炉冷
３）結果
第４図（ａ），（ｂ），（ｃ），（ｄ）は顕微鏡組織
を示すものである。本発明材は第４図（ａ）に示すよう
にNiを添加しても完全にフェライト化されている。な
お、第４図（ｂ），（ｃ）は、それぞれNiが1.05％、1.
98％である比較材を示し、第４図（ｄ）は従来材FCD40
（熱処理材）を示すものである。また熱処理を施したも
のの機械的性質を第５図、第６図に示す。
本発明の0.53％Ni材は1.05％Ni比較材に較べて引張強
さ、耐力はやや劣るものの、伸びが著しく改善され、室
温での衝撃値、低温（−40℃）での衝撃値も優れてい
る。また、本発明の0.53％Ni材は、1.98％Ni比較材に較
べて引張強さ、耐力は劣るものの、伸びが著しく改善さ
れ、室温での衝撃値も優れ、特に低温（−40℃）での衝
撃値が改善される。
さらに、本発明の0.53％Ni材は、引張強さ、耐力はFC
D40熱処理材と同程度であるが、伸び、室温での衝撃値
が著しく改善され、特に低温（−40℃）での衝撃値が改
善される。
〔実施例.3〕
１）化学成分
２）鋳 型
25mm厚さ×250mm長さのＹブロックの鋳型をCO2鋳型で
造型した。
３）結 果
上記鋳型に溶湯を注入して作成したテストピースにつ
いての調査結果を以下に記す。
第７図（ａ），（ｂ），（ｃ）に顕微鏡組織を示す。
本発明材は第７図（ａ）であり、第７図（ｂ），（ｃ）
は、それぞれNiが1.05％、1.98％である比較材を示すも
のである。FCD40、FCD60は黒鉛粒数が本発明材に較べて
少ない。これは本発明材がBiを添加しているため黒鉛粒
数が多くなっている。
第８図、第９図に機械的性質を示すが、本発明の0.53
％Ni材は、1.05％Ni比較材に較べて引張強さ、耐力はや
や劣るものの、伸び、室温での衝撃値、低温（−40℃）
での衝撃値は高い値を示している。また、本発明の0.53
％Ni材は、1.98％Ni比較材に較べて引張強さ、耐力は劣
るものの、伸び、室温での衝撃値、低温（−40℃）での
衝撃値は高い値を示し、特に低温（−40℃）での衝撃値
は２倍以上高い値を示している。
さらに、本発明の0.51％Ni材は引張強さ、耐力はFCD4
0に較べて多少劣るものの、伸び、室温での衝撃値はき
わめて高い値を示し、特に低温（−40℃）での衝撃値が
格段に改善される。このように本発明材は、従来の材質
に較べて極めて優れた材質であることがわかる。
また、本発明の0.51％Ni材は、FCD60に比べて、第９
図に示すように、伸び、室温衝撃値及び低温（−40℃）
での衝撃値が極めて優れていることがわかる。
〔実施例.4〕
１）化学成分
〔実施例.3〕と同じ。
２）熱処理
〔実施例.3〕で得られた素材（除FCD60）を次の熱処
理サイクルにてフェライト化焼なましを行った。
900℃×２時間→720℃×２時間→炉冷
３）結 果
第10図（ａ），（ｂ），（ｃ）は顕微鏡組織を示すも
のである。本発明材は第10図（ａ）であり、第10図
（ｂ），（ｃ）は、それぞれNiが1.05％、1.98％である
比較材を示すものである。熱処理をほどこしたものにお
いても、本発明材の黒鉛粒数はFCD40熱処理材よりも多
いことが明らかである。
第11図、第12図に機械的性質を示す。本発明の0.53％
Ni材は、1.05％Ni比較材に較べて引張強さ、耐力はやや
劣るものの、伸びが著しく改善され、室温での衝撃値、
低温（−40℃）での衝撃値も優れている。また、本発明
の0.53％Ni材は、1.98％Ni比較材に較べて引張強さ、耐
力は劣るものの、伸びが著しく改善され、室温での衝撃
値もやや優れ、特に低温（−40℃）での衝撃値が改善さ
れる。
さらに、本発明の0.51％Ni材は引張強さ、耐力はFCD4
0熱処理材と同程度であるが、伸び、室温での衝撃値は
著しく改善され、特に低温（−40℃）での衝撃値が改善
される。
〔発明の効果〕
以上の説明で明らかなように、本発明の低温靭性にす
ぐれた球状黒鉛鋳鉄は、前述のとおり鋳放し状態でより
優れた伸び及び衝撃値、とくに−40℃程度の低温におい
て優れた衝撃値を有するものであるが、熱処理を施すと
鋳放し材に較べ、更に優れた伸び、衝撃値、特に低温で
の衝撃値が改善される。
すわわち、球状黒鉛鋳鉄の機械的性質の向上と製造原
価の低減に著しい効果をもたらすものである。Description: TECHNICAL FIELD The present invention relates to a spheroidal graphite cast iron having excellent low-temperature toughness. Conventional technology Conventional spheroidal graphite cast iron with ferrite ground FCD37 or F
CD40 has high elongation and impact values, but low tensile strength. FCD50 or FCD60, which is pearlite, has high tensile strength and proof stress but low elongation and impact values, especially low-temperature impact values. To improve these, a method of adding Ni is disclosed in
No. 33897 discloses this. According to the present invention, an impact value of at least 1.7 kgf · m / cm 2 at −15 ° C. can be obtained. Also, C: 0.3 to 4.2%, Si: 1.3 to 2.2%, Ni: 1 to 5%, M
Japanese Patent Application Laid-Open No. 53-97918 discloses an as-cast pearlite terrestrial graphite cast iron comprising g: 0.02 to 0.08% and a balance of Fe and impurities such as Mn, Cr, Sn, V, Mo, and Cu. In order to obtain a uniform pearlite within the same product, the content of Si, which is a ferrite-promoting element, is suppressed to a low value, and Ni (1 to 5%) is contained to stabilize pearlite. It is to decrease. Furthermore, by weight ratio 3.3-4.4% C, 2.0-3.5% Si,
And at least one of Mg, Ca, and rare earth elements in an amount sufficient for spheroidization, and Mn, which is a ferrite formation inhibiting element, is 0.15%
In the following, P is 0.06% or less, Cr is 0.05% or less, Ni is 0.15% or less, Cu is 0.06% or less, Sn is 0.01% or less, and at least one of Bi and Te is contained in high-purity pig iron whose balance is iron. To 0.
Japanese Patent Publication No. 47-18337 discloses a method for producing a thick ferrite type spheroidal graphite cast iron which is cast at a content of 005 to 0.02%. In this method, the thickness at which Cr and Mn are extremely bent is 50 mm.
This method is intended for the above castings, and this method only pursues ferrite conversion.
It states that Si is allowed up to 3.5%, and that Ni, which is a ferrite inhibiting element, is preferably simply lower (0.15% or less). Recently, cast parts for automobiles and industrial use are required to have higher toughness and are often used even at a low temperature of about −40 ° C., and a high impact value is required even at such a low temperature. Therefore, the present inventors improved the elongation and the impact value at a low temperature of about −40 ° C. by adding Ni by 0.5 to less than 1.0% by weight. Further, in the above invention, ferritizing annealing is performed in the examples on condition that the ferrite structure is used.
In order to reduce the manufacturing cost, it is most preferable to use the as-cast condition without annealing. Also, by adding a small amount of Bi, the number of graphite
By setting the particle size to at least 10 g / mm 2 , pearlite is reduced, and even if heat treatment is not performed, or even if heat treatment is performed, sufficient elongation and impact value are ensured by low-temperature and short-time heat treatment. Needless to say, higher annealing and toughness can be obtained by annealing to obtain a ferrite structure. The object of the present invention is to improve the elongation and impact value, especially the impact value at low temperature of about -40 ° C, and to eliminate or perform heat treatment by adding Bi as necessary. It is an object of the present invention to provide a spheroidal graphite cast iron which can reduce the production cost only by performing a heat treatment at a low temperature for a short time. Means for Solving the Problems The spheroidal graphite cast iron having excellent low-temperature toughness of the present invention is as follows: C: 3.0 to 4.0% by weight% Si: 1.5 to 2.3% Mn: <0.3% P: <0.03% Ni: 0.5 to 1.0% Cr: <0.10% Mg: 0.02-0.06% Consists of residual iron and unavoidable impurities and has a CE value of 3.9-
Use 4.6% molten metal or add 0.005 to 0.03% Bi as needed to the molten metal having the above composition, inoculate at the same time or after the addition of Bi, and reduce the number of graphite particles to 300 particles / mm 2 or more. It is characterized by having done. The residual content of Bi is preferably set to 0.0015 to 0.015%. In the present invention, the CE value is one third of the weight percent of Si and C
And the weight percent of Next, the reasons for limiting the numerical values will be described. If C is less than 3.0%, castability will be poor and pearlite will increase due to a decrease in the number of graphite particles. On the other hand, if it exceeds 4.0%, quiche graphite tends to be produced, and the strength is reduced. If the content of Si is less than 1.5%, carbides are easily precipitated, and the impact value and elongation decrease. If it exceeds 2.3%, the impact value and elongation decrease due to the effect of silico ferrite. If Mn exceeds 0.3%, pearlite increases and impact value and elongation decrease. If P exceeds 0.03%, the impact value and elongation decrease due to the influence of steadite. If Ni is less than 0.5%, strength cannot be obtained. On the other hand, when the content is 1.0% or more, elongation at a low temperature (−40 ° C.) and impact value decrease. If the Cr content exceeds 0.1%, carbides are easily precipitated, and the impact value and elongation decrease. If the content of Mg is less than 0.02%, the graphite will not be spheroidized, and if the content is more than 0.06%, not only shrinkage cavities and carbides will be easily generated, but also it will be economically disadvantageous. When the CE value is less than 3.9%, carbides are easily generated, and castability is also deteriorated. If it exceeds 4.6%, quiche graphite is likely to be produced. If Bi has a residual content of less than 0.0015%, the effect of increasing the number of graphite particles is reduced, and as a result, cementite is generated in the as-cast structure. If the residual content exceeds 0.0150%, the effect of Bi to inhibit the spheroidization of graphite appears, and the spheroidization ratio of graphite becomes 70% or less, deteriorating the mechanical properties. Bi has a low melt yield rate in molten spheroidal graphite cast iron, and its fluctuation is large.
In order to reach 15 to 0.0150%, add 0.005 to 0.030
Must be set to%. If the number of graphite particles is less than 300 pcs / mm 2 , the distance between the graphites will increase, and pearlite will increase, resulting in a decrease in impact value and elongation. [Operation] In the present invention, a spheroidal graphite cast iron having high tensile strength and proof stress, and high elongation and impact value, particularly high impact value at −40 ° C., can be obtained even as cast. Further, a higher impact value and elongation can be obtained by performing a ferrite annealing heat treatment. [Example 1] 1) Chemical components 2) Mold A 25 mm thick x 250 mm long Y block mold was formed using a CO 2 mold. 3) Results Investigation results of test pieces made by injecting the molten metal into the above molds are described below. 1 (a), (b), (c), (d) and (e) show the microscopic structures. The material of the present invention is shown in FIG.
FIGS. 1 (b) and 1 (c) show comparative materials in which Ni is 1.05% and 1.98%, respectively, and FIGS. 1 (d) and 1 (e) show conventional materials, respectively.
It shows FCD40 and FCD60. 2 and 3 show mechanical properties. 0.53% of the present invention
Although the Ni material has a slightly lower tensile strength and proof strength than the 1.05% Ni comparative material, the elongation, the impact value at room temperature, and the impact value at a low temperature (−40 ° C.) are high. In addition, 0.53% of the present invention
Although the Ni material has slightly lower tensile strength and proof stress than the 1.98% Ni comparative material, it shows high values of elongation, impact value at room temperature, and impact value at low temperature (-40 ° C), especially at low temperature (− The impact value at 40 ° C) is more than twice as high. Furthermore, the 0.53% Ni material of the present invention has tensile strength and proof stress of FCD4
Equivalent to 0, elongation, high impact value at room temperature,
In particular, the impact value at a low temperature (−40 ° C.) is more than twice as high. Further, the 0.53% Ni material of the present invention has a lower tensile strength and proof stress than the FCD60 material, but as shown in FIG. 3, has an excellent elongation and an excellent impact value at room temperature, and particularly has a low temperature (−40). ℃)
The impact value at is greatly improved. Thus, it can be seen that the material of the present invention is an extremely excellent material at a low temperature (−40 ° C.) as compared with the conventional material. [Example 2] 1) Chemical components Same as [Example 1]. 2) Heat treatment The material (excluding FCD60) obtained in [Example 1] was subjected to ferrite annealing in the next heat treatment cycle. 900 ° C. × 2 hours → 720 ° C. × 2 hours → furnace cooling 3) Results FIGS. 4 (a), (b), (c) and (d) show microscopic structures. As shown in FIG. 4 (a), the material of the present invention is completely ferritized even when Ni is added. 4 (b) and 4 (c) show that the Ni content is 1.05% and the Ni content is 1.0%, respectively.
FIG. 4 (d) shows a conventional material FCD40 which is 98%.
(Heat-treated material). 5 and 6 show the mechanical properties of the heat-treated one. The 0.53% Ni material of the present invention has slightly improved tensile strength and proof stress compared with the 1.05% Ni comparative material, but has significantly improved elongation and excellent impact value at room temperature and impact value at low temperature (-40 ° C). ing. Also, the 0.53% Ni material of the present invention has significantly improved elongation and excellent impact value at room temperature, although the tensile strength and proof stress are inferior to the 1.98% Ni comparative material, especially at low temperatures (−40 ° C.). Impact value is improved. Further, the 0.53% Ni material of the present invention has a tensile strength and a proof stress of FC.
It is comparable to the D40 heat-treated material, but has significantly improved elongation and impact value at room temperature, especially at low temperature (-40 ° C). [Example.3] 1) Chemical components 2) Mold A 25 mm thick x 250 mm long Y block mold was formed using a CO 2 mold. 3) Results Investigation results of test pieces made by injecting the molten metal into the above molds are described below. FIGS. 7 (a), (b) and (c) show microscopic structures.
FIG. 7 (a) shows the material of the present invention, and FIGS. 7 (b) and 7 (c).
Indicates a comparative material in which Ni is 1.05% and 1.98%, respectively. FCD40 and FCD60 have a smaller number of graphite particles than the material of the present invention. This is because the material of the present invention contains Bi and the number of graphite particles is large. FIGS. 8 and 9 show the mechanical properties.
% Ni material has slightly lower tensile strength and proof strength than 1.05% Ni comparative material, but elongation, impact value at room temperature, low temperature (-40 ℃)
Shows a high impact value. In addition, 0.53 of the present invention
Although the tensile strength and proof stress are inferior to the 1.98% Ni comparative material, the elongation, the impact value at room temperature, and the impact value at low temperature (−40 ° C.) show high values, especially at low temperature (−40%). The impact value at 40 ° C) is more than twice as high. Further, the 0.51% Ni material of the present invention has tensile strength and proof stress of FCD4
Although slightly inferior to 0, the elongation and the impact value at room temperature show extremely high values, and particularly, the impact value at a low temperature (−40 ° C.) is remarkably improved. Thus, it can be seen that the material of the present invention is an extremely excellent material as compared with the conventional material. In addition, the 0.51% Ni material of the present invention has a ninth
As shown, elongation, room temperature impact value and low temperature (-40 ℃)
It can be seen that the impact value was extremely excellent. [Example.4] 1) Chemical components Same as [Example.3]. 2) Heat treatment The material (excluding FCD60) obtained in [Example 3] was subjected to ferrite annealing in the next heat treatment cycle. 900 ° C × 2 hours → 720 ° C × 2 hours → Furnace cooling 3) Results Figs. 10 (a), (b) and (c) show the microscopic structures. The material of the present invention is FIG. 10 (a), and FIGS. 10 (b) and (c) show comparative materials in which Ni is 1.05% and 1.98%, respectively. It is clear that even in the heat-treated material, the number of graphite particles of the material of the present invention is larger than that of the FCD40 heat-treated material. Fig. 11 and Fig. 12 show the mechanical properties. 0.53% of the present invention
Although the Ni material has a slightly lower tensile strength and proof stress than the 1.05% Ni comparative material, the elongation is significantly improved, the impact value at room temperature,
Excellent impact value at low temperature (-40 ° C). Also, the 0.53% Ni material of the present invention has a significantly improved elongation and a slightly superior impact value at room temperature, particularly at a low temperature (-40 ° C), although the tensile strength and proof stress are inferior to the 1.98% Ni comparative material. The impact value is improved. Further, the 0.51% Ni material of the present invention has tensile strength and proof stress of FCD4
0 Equivalent to the heat-treated material, but the elongation and the impact value at room temperature are remarkably improved, especially the impact value at low temperature (−40 ° C.). [Effects of the Invention] As is clear from the above description, the spheroidal graphite cast iron excellent in low-temperature toughness of the present invention has better elongation and impact value in the as-cast state as described above, particularly at a low temperature of about -40 ° C. Although it has an excellent impact value, the heat treatment improves the elongation and impact value, especially at low temperature, as compared with the as-cast material. In other words, it has a remarkable effect on improving mechanical properties of spheroidal graphite cast iron and reducing manufacturing costs.
【図面の簡単な説明】
第１図（ａ），（ｂ），（ｃ），（ｄ），（ｅ）、第４
図（ａ），（ｂ），（ｃ），（ｄ）、第７図（ａ），
（ｂ），（ｃ）、第10図（ａ），（ｂ），（ｃ）はとも
に金属顕微鏡組織写真、
第２図，第３図，第５図，第６図，第８図，第９図，第
11図，第12図はともに機械的性質を示すグラフである。BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 (a), (b), (c), (d), (e), 4th
Figures (a), (b), (c), (d), FIG. 7 (a),
(B), (c), and FIGS. 10 (a), (b), and (c) are metallographic micrographs, respectively, and FIGS. 2, 3, 5, 5, 6, 8, and Fig. 9
11 and 12 are graphs showing mechanical properties.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 小幡 文雄 福岡県京都郡苅田町長浜町35番地 日立 金属株式会社九州工場内 (72)発明者 酒井 潤 埼玉県和光市中央１丁目４番１号 株式 会社本田技術研究所内 (72)発明者 夏目 毅 埼玉県和光市中央１丁目４番１号 株式 会社本田技術研究所内 (56)参考文献 特開 昭53−97918（ＪＰ，Ａ) 特公 昭47−18337（ＪＰ，Ｂ１) ────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Fumio Obata Hitachi 35, Nagahama-cho, Kanda-cho, Kyoto-gun, Fukuoka Metal Corporation Kyushu Factory (72) Inventor Jun Sakai 1-4-1 Chuo, Wako-shi, Saitama Inside Honda Technical Research Institute (72) Inventor Takeshi Natsume 1-4-1 Chuo, Wako-shi, Saitama Inside Honda Technical Research Institute (56) References JP-A-53-97918 (JP, A) JP-B-47-18337 (JP, B1)
Claims (1)
4.6％である組成の溶湯に0.005〜0.03％のBiを添加し、
該Bi添加と同時に又は添加後に接種を行ない、黒鉛粒数
を300ケ/mm2以上とした低温靭性にすぐれた球状黒鉛鋳
鉄。 ２．Biの含有量を0.0015〜0.015％とした特許請求の範
囲第１項記載の低温靭性にすぐれた球状黒鉛鋳鉄。(57) [Claims] C by weight: 3.0 to 4.0% Si: 1.5 to 2.3% Mn: <0.3% P: <0.03% Ni: less than 0.5 to 1.0% Cr: <0.10% Mg: 0.02 to 0.06% From residual iron and unavoidable impurities And CE value is 3.9 ~
Add 0.005-0.03% Bi to the molten metal of 4.6% composition,
Spheroidal graphite cast iron excellent in low-temperature toughness, inoculated simultaneously with or after the addition of Bi and having a graphite particle number of 300 / mm 2 or more. 2. The spheroidal graphite cast iron having excellent low-temperature toughness according to claim 1, wherein the Bi content is 0.0015 to 0.015%.
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62323812A JP2716063B2 (en) | 1987-03-09 | 1987-12-23 | Spheroidal graphite cast iron with excellent low temperature toughness |
| GB8805483A GB2203448B (en) | 1987-03-09 | 1988-03-08 | Nodular cast iron |
| DE3807455A DE3807455C2 (en) | 1987-03-09 | 1988-03-08 | Nodular cast iron with high impact strength and method for its treatment |
| US07/165,873 US4889687A (en) | 1987-03-09 | 1988-03-09 | Nodular cast iron having a high impact strength and process of treating the same |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62-52205 | 1987-03-09 | ||
| JP5220587 | 1987-03-09 | ||
| JP62323812A JP2716063B2 (en) | 1987-03-09 | 1987-12-23 | Spheroidal graphite cast iron with excellent low temperature toughness |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| JPH01245A JPH01245A (en) | 1989-01-05 |
| JPS64245A JPS64245A (en) | 1989-01-05 |
| JP2716063B2 true JP2716063B2 (en) | 1998-02-18 |
Family
ID=26392817
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62323812A Expired - Fee Related JP2716063B2 (en) | 1987-03-09 | 1987-12-23 | Spheroidal graphite cast iron with excellent low temperature toughness |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2716063B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2730959B2 (en) * | 1988-03-09 | 1998-03-25 | 日立金属株式会社 | Spheroidal graphite cast iron and method for producing the same |
| JPH06116677A (en) * | 1992-10-06 | 1994-04-26 | Nippon Steel Corp | Ductile cast iron material excellent in tenacity and surface roughening resistance |
| AU5106400A (en) * | 1999-06-08 | 2000-12-28 | Asahi Tec Corporation | Non-austempered spheroidal graphite cast iron |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5917183B2 (en) * | 1977-02-09 | 1984-04-19 | 日立金属株式会社 | As-cast pearlite terrestrial graphite cast iron |
-
1987
- 1987-12-23 JP JP62323812A patent/JP2716063B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPS64245A (en) | 1989-01-05 |
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