JPS5917184B2 - As-cast pearlite terrestrial graphite cast iron - Google Patents
As-cast pearlite terrestrial graphite cast ironInfo
- Publication number
- JPS5917184B2 JPS5917184B2 JP1240177A JP1240177A JPS5917184B2 JP S5917184 B2 JPS5917184 B2 JP S5917184B2 JP 1240177 A JP1240177 A JP 1240177A JP 1240177 A JP1240177 A JP 1240177A JP S5917184 B2 JPS5917184 B2 JP S5917184B2
- Authority
- JP
- Japan
- Prior art keywords
- pearlite
- terrestrial
- cast iron
- cast
- graphite cast
- 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
Links
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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】
本発明は基地組織がパーライト及びフェライトの混合組
織(以下単にパーライト地と記す)からなる球状黒鉛鋳
鉄に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to spheroidal graphite cast iron whose matrix structure is a mixed structure of pearlite and ferrite (hereinafter simply referred to as pearlite base).
基地組織がパーライト地である球状黒鉛鋳鉄は鋳放し状
態で容易に得ることができるので、古くから鋳放し状態
で製造され、又使用されている。Spheroidal graphite cast iron, whose base structure is pearlite, can be easily obtained in an as-cast state, so it has been manufactured and used in an as-cast state for a long time.
この場合、パーライト地球状黒鉛鋳鉄を得るためには、
目的とする硬度と製品肉厚に応じてMn量を増減する方
法によっていたが、Mnはパーライト化を促進すると同
時にセメンタイトの晶(析)出を促進する元素であるた
め、必要以上にMnを含有すると上記の好ましからざる
組織により局部的に硬度が高くなり、脆くなったり、あ
るいは切削性が大幅に低下するなどの問題があった。In this case, to obtain pearlitic terrestrial graphite cast iron,
The method used was to increase or decrease the amount of Mn depending on the target hardness and product wall thickness, but since Mn is an element that promotes pearlite formation and at the same time promotes the crystallization (precipitation) of cementite, it is necessary to contain more Mn than necessary. Then, due to the above-mentioned undesirable structure, there were problems such as locally increasing hardness, making the steel brittle, or significantly reducing machinability.
従って、鋳放し状態で使用されるパーライト地球状黒鉛
鋳鉄を製造する場合、上記の好ましからざる組織の晶(
析)出を防止するため、一般的にはSi含有量を高くす
る(2.5〜3.0係)ことによりなされてきた。Therefore, when manufacturing pearlitic terrestrial graphite cast iron to be used in the as-cast state, crystals of the above-mentioned undesirable structure (
In order to prevent precipitation, it has generally been done by increasing the Si content (2.5 to 3.0).
このように従来の方法によって製造されたパーライト地
球状黒鉛鋳鉄は、Mn量及びSi量が高いことに起因し
て鋳物の鋳型内での冷却速度の影響を受けやすく、同一
製品内でも均一なパーライト組織とはなり得なかった。Pearlite terrestrial graphite cast iron manufactured by conventional methods is susceptible to the cooling rate within the casting mold due to its high Mn and Si contents, and even within the same product, pearlite is uniform. It could not become an organization.
即ち同一製品であっても、肉厚が薄く、冷却速度の速い
ところでは完全パーライト地となり硬度は高い。That is, even if the product is the same, if the wall thickness is thin and the cooling rate is fast, it will become completely pearlite and have high hardness.
逆に厚肉部など冷却速度の遅いところでは、フェライト
地を多量に含んだパーライト地組織となり硬度は低く、
軟かくなる傾向が強い。On the other hand, in areas where the cooling rate is slow, such as in thick-walled areas, the hardness is low due to the pearlite texture containing a large amount of ferrite.
It has a strong tendency to become soft.
さらに各ヒート間の球状化処理方法、接種効果の差や各
枠組の注湯終了から型ばらしまでの鋳型内冷却時間の差
、接種効果のフェーディング現象による差など種々の変
動要因の影響により、同一製品を多量生産する場合、製
品毎の組織、硬度に大きなばらつきを生じるのが常であ
る。Furthermore, due to the influence of various variables such as the spheroidization treatment method between each heat, the difference in inoculation effect, the difference in the cooling time in the mold from the end of pouring of each framework to the mold release, and the difference due to the fading phenomenon of inoculation effect, When mass-producing the same product, there are usually large variations in structure and hardness from product to product.
これらは偏にフェライト化促進元素であるSiと、パー
ライト化促進元素であるMnとの作用の相反する元素を
同時に多量に含有させたためである。This is because Si, which is an element that promotes ferrite formation, and Mn, which is an element that promotes pearlite formation, are contained in large quantities at the same time, elements that have opposite effects.
本発明は上記の点に鑑み、フェライト化促進元素である
Si量を低く抑え、Mn、Cr、Vなどの炭化物(セメ
ンタイト)生成元素をも低く抑え炭化物生成傾向のない
、パーライト化促進元素であるSnを含有させることに
より、より均一な組織、硬度及び性質をもった鋳放しパ
ーライト地球状黒鉛鋳鉄を提供するものである。In view of the above points, the present invention is a pearlite-promoting element that suppresses the amount of Si, which is a ferrite-promoting element, and also suppresses carbide (cementite)-forming elements such as Mn, Cr, and V, and does not have a tendency to form carbides. The inclusion of Sn provides as-cast pearlite terrestrial graphite cast iron with more uniform structure, hardness, and properties.
球状黒鉛鋳鉄中に現われるセメンタイト組織の晶(析)
出を抑制できればフェライト化促進元素であるSi含有
量を低くすることが可能で、そのことによりパーライト
化が促進されるのみでなく、Si含有量が高いことに起
因する組織、硬度及び性質のばらつきを減少させること
が期待できる。Crystallization of cementite structure appearing in spheroidal graphite cast iron
If this can be suppressed, it is possible to lower the Si content, which is an element that promotes ferrite formation, which not only promotes pearlite formation, but also reduces variations in structure, hardness, and properties caused by high Si content. can be expected to decrease.
又球状黒鉛鋳鉄中に通常含有されるパーライト安定化元
素は、Mn、Cr、V、Sn、Mo、Cuなどであるが
、このうち共晶セル境界部に偏析し、セメンタイト組織
の晶(析)出を促進する元素はMn 。Pearlite stabilizing elements normally contained in spheroidal graphite cast iron include Mn, Cr, V, Sn, Mo, Cu, etc., but these elements segregate at the eutectic cell boundaries and cause crystallization of the cementite structure. The element that promotes production is Mn.
Cr、V、M6である。They are Cr, V, and M6.
従ってこれらの元素を上記の好ましからざる組織の晶(
析)出限界以下に抑叫くえ、その代りにSnを目的とす
る硬度に合わせて適量含有させることにより、Si量を
減少させ得るものである。Therefore, these elements can be mixed into crystals with the above-mentioned unfavorable structure (
The amount of Si can be reduced by suppressing the amount of Sn to below the precipitation limit and instead containing an appropriate amount of Sn in accordance with the target hardness.
以下本発明を実施例に基いて詳細に説明する。The present invention will be explained in detail below based on examples.
実施例
低周波炉に球状黒鉛鋳鉄戻り屑40%、ソレルメタル(
商品名)20係、鋼屑40係を配合溶解し、昇温、成分
調整後出湯時にFe−8Fe−8i−%Mg)で球状化
処理を行った。Example: In a low frequency furnace, 40% of spheroidal graphite cast iron return waste and Sorel metal (
Product name) 20 parts and steel scrap 40 parts were blended and melted, and after raising the temperature and adjusting the composition, a spheroidization treatment was performed with Fe-8Fe-8i-%Mg) at the time of tapping.
更にFe−8iで0.6%の接種を施し、肉厚の異なる
板が放射状に並んだ空隙部を有する砂型鋳型に鋳込んだ
。Further, the material was inoculated with 0.6% Fe-8i and cast into a sand mold having a cavity in which plates of different thicknesses were arranged radially.
この場合の鋼屑は市販の良質鋼屑を使用した。In this case, commercially available high quality steel scrap was used.
この時の化学成分を第1表に示し、又板厚での機械的性
質を第2表に示し、板厚10mm及び70mmにおける
それぞれの顕微鏡組織を第1図及び第2図に示す。The chemical components at this time are shown in Table 1, the mechanical properties at different plate thicknesses are shown in Table 2, and the microscopic structures at plate thicknesses of 10 mm and 70 mm are shown in FIGS. 1 and 2, respectively.
第2表から明らかなように板厚5mmにおいては若干の
セメンタイトが認められるが、板厚10mm以上ではパ
ーライトとフェライトの混合組織であり板厚1107I
Lと70mmとのブリネル硬さの差は24であり引張り
強さでは7.2に9/−であり、10m7IL以上の板
厚ではいずれも良好な伸びを示している。As is clear from Table 2, a small amount of cementite is observed when the plate thickness is 5 mm, but when the plate thickness is 10 mm or more, the structure is a mixture of pearlite and ferrite, and the plate thickness is 1107I.
The difference in Brinell hardness between L and 70 mm is 24, and the tensile strength is 7.2 to 9/-, and both exhibit good elongation at plate thicknesses of 10 m7IL or more.
この場合板厚5闘のものについては引張試験片の加工が
困難なため試験は行っていない。In this case, the test was not conducted on the plate having a thickness of 5 mm because it was difficult to process the tensile test piece.
又第1表の分析結果かられかるように通常のパーライト
地球状黒鉛鋳鉄に多量に含有されているMnは0.16
%と非常に低い含有量となっている。Also, as can be seen from the analysis results in Table 1, the large amount of Mn contained in ordinary pearlite terrestrial graphite cast iron is 0.16.
%, the content is very low.
共晶セル境界に偏析しやすい等の含有量を低く保ち、更
にCr、Cu、Mo、V等の総合有量を0.1042%
とすることにより、セメンタイト組織の晶(析)出を防
止することができた。The content of Cr, Cu, Mo, V, etc., which is likely to segregate at the eutectic cell boundary, is kept low, and the total content of Cr, Cu, Mo, V, etc. is reduced to 0.1042%.
By doing so, crystallization (precipitation) of cementite structure could be prevented.
これらのことにより板厚10mmにおいても良好な伸び
を示すものである。Due to these factors, it shows good elongation even at a plate thickness of 10 mm.
本発明においては不可避的に含有される各成分それぞれ
単独の炭化物を晶(析)出させる限界含有量は、Cr、
Vで0.10%であり、Moは0.25係である。In the present invention, the limit content for crystallizing (precipitating) individual carbides of each component that is unavoidably contained is Cr,
V is 0.10%, and Mo is 0.25%.
Cnはそれ自体では炭化物析出促進元素ではないが、C
r、V、Mo、Cuの総和量が0.50係を超えると各
元素側々には限界含有量以下であっても、やはり炭化物
の析出が著しくなるため、この量を超えてはならない。Cn itself is not an element that promotes carbide precipitation, but Cn
If the total amount of r, V, Mo, and Cu exceeds a factor of 0.50, carbide precipitation will still be significant even if the content of each element is below the limit, so this amount should not be exceeded.
またSnを含有させて基地組織の均一なパーライト化を
図るためには、他のパーライト化促進元素含有量を低く
保たなければ、その相乗効果により、基地組織のばらつ
きを招くことになる。Furthermore, in order to uniformly transform the matrix structure into pearlite by incorporating Sn, unless the content of other pearlite-promoting elements is kept low, the synergistic effect of these elements will cause variations in the matrix structure.
例えばCuはその含有量が0.20%まではパーライト
化促進作用は殆んどないが0.25%以上になると、そ
の作用効果が急増してくる。For example, Cu has almost no effect of promoting pearlite formation up to 0.20%, but when the content exceeds 0.25%, its effect rapidly increases.
従ってCu含有量が0.10%のものと0.30%のも
のにそれぞれ0.050%のSnを含有させると、後者
の場合の方がよりパーライト化が促進され、硬度が高く
、引張強さも高いものとなる。Therefore, if 0.050% Sn is added to a Cu content of 0.10% and 0.30%, the latter will promote pearlite formation, have higher hardness, and have higher tensile strength. It will also be expensive.
これはCu及びSnのパーライト化促進作用の相乗効果
によるものであり、Sn添加により。This is due to the synergistic effect of the pearlitization promoting effects of Cu and Sn, and is due to the addition of Sn.
ヒート間のばらつきの少ない硬度を持った均一なパーラ
イト組織を得るためには、Cu含有量を0.20%以下
に保つ必要がある。In order to obtain a uniform pearlite structure with hardness with little variation between heats, it is necessary to keep the Cu content at 0.20% or less.
またMnの炭化物品(析)出促進作用は板厚によっても
異なるが、冷却速度の速い薄肉においては0.30%以
上にな:るとその作用が顕著になるためこれ以下にする
必要がある。The effect of Mn on accelerating the precipitation of carbide products (precipitation) varies depending on the plate thickness, but in thin walls where the cooling rate is fast, the effect becomes noticeable at 0.30% or more, so it is necessary to reduce the amount below this value. .
Mnが通常作業で達成できる0、1〜0.2係であれば
Siは2.0係以下の範囲で良く、この時基地組織をパ
ーライト化させるに必要なSn量は、製品肉厚と目標硬
度により多少の差はあるが、0.025%以下のSn量
ではパーライト化促進作用が低下し薄肉部でも充分なパ
ーライト組織は得られない。If Mn is 0.1 to 0.2, which can be achieved in normal operations, then Si may be in the range of 2.0 or less, and the amount of Sn required to turn the base structure into pearlite depends on the product thickness and target. Although there are some differences depending on the hardness, if the Sn content is 0.025% or less, the pearlite formation promotion effect decreases and a sufficient pearlite structure cannot be obtained even in a thin wall part.
上限の0.2係は厚肉部において完全パーライト組織に
する必要な量であり、それ以上含有させる必要はない。The upper limit of 0.2 is the amount necessary to form a complete pearlite structure in the thick part, and there is no need to contain more than that.
第3表は従来のパーライト地球状黒鉛鋳鉄の化学成分、
第4表はその機械的性質を示すものである。Table 3 shows the chemical composition of conventional pearlitic terrestrial graphite cast iron.
Table 4 shows its mechanical properties.
この比較例によって本発明によるパーライト地球状黒鉛
鋳鉄がいかにすぐれているかが明白である。This comparative example clearly shows how superior the pearlitic terrestrial graphite cast iron according to the invention is.
比較例
低周波炉に球状黒鉛鋳鉄戻り屑40係、ソレルメタル(
商品名)20%、鋼屑40係を配合、溶解し昇温、成分
調整後出湯時にFe−Fe−8i−5%Mg)で球状化
処理を行った。Comparative example: 40 pieces of spheroidal graphite cast iron returned to a low frequency furnace, Sorel metal (
After blending 20% (trade name) and 40% steel scrap, melting and raising the temperature, and adjusting the composition, a spheroidizing treatment was performed with Fe-Fe-8i-5%Mg).
この溶湯にFe−8iで0.6係の接種を施し、実施例
と同様の試験片を鋳込んだ。This molten metal was inoculated with Fe-8i at a rate of 0.6, and a test piece similar to that in the example was cast.
この場合の鋼屑は市販の一般鋼屑を使用した。Commercially available general steel scrap was used as the steel scrap in this case.
化学成分及び各板厚での機械的性質はそれぞれ第3表及
び第4表に示す通りで、板厚10mm及び70mrnに
おけるそれぞれの顕微鏡組織を第3図及び第4図に示す
。The chemical components and mechanical properties at each plate thickness are shown in Tables 3 and 4, respectively, and the microstructures at plate thicknesses of 10 mm and 70 mrn are shown in FIGS. 3 and 4, respectively.
本例の場合には第3表、第4表及び第3図、第4図から
明らかなように板厚5mm、 10v271+及び3
0mmにおいてはセメンタイトが晶(析)出し硬度が高
く、従って伸びが極端に小さくなっている。In the case of this example, as is clear from Tables 3 and 4 and Figures 3 and 4, the plate thickness is 5 mm, 10v271+ and 3
At 0 mm, cementite crystallizes (precipitates) and has high hardness, so the elongation is extremely small.
板厚5mmにおいては基地組織の大部分がセメンタイト
であり白銑化傾向の著しいことが明白である。When the plate thickness is 5 mm, most of the base structure is cementite, and it is clear that there is a marked tendency to white iron.
逆に板厚70闘においてはパーライトよりもフェライト
量が多く引張強さは低く、伸びが増加している。Conversely, when the plate thickness is 70mm, the amount of ferrite is higher than that of pearlite, the tensile strength is lower, and the elongation is increased.
板厚10mrn及び70mmでのブリネルかたさの差は
67であり、引張強さでは23kg/maの差があり、
いずれも本発明の実施例と比較してばらつきの大きいこ
とが明らかである。The difference in Brinell hardness between plate thicknesses of 10 mrn and 70 mm is 67, and the difference in tensile strength is 23 kg/ma.
It is clear that there are large variations in both cases compared to the examples of the present invention.
この場合のCr、Mo、V、Snの総合有量は0.18
5%であり特許請求の範囲第3項の限定数値内ではある
が、Cr含有量が炭化物主成限界値の0,10%を超え
ており、しかもMn含有量も0.58%と非常に高い。In this case, the total amount of Cr, Mo, V, and Sn is 0.18
5%, which is within the numerical limit set forth in claim 3, but the Cr content exceeds the carbide main formation limit value of 0.10%, and the Mn content is also extremely high at 0.58%. expensive.
これらの元素の含有量が高いため前述のように薄肉部に
おいて炭化物を主成し、一方Si量が2.66%と高い
ことにより厚肉部でのパーライト量が減少し、硬度が低
下することを示している。Because the content of these elements is high, carbides mainly form in the thin-walled parts as mentioned above, while the amount of Si is high at 2.66%, so the amount of pearlite in the thick-walled parts decreases, resulting in a decrease in hardness. It shows.
以上の説明で明らかなように炭化物生成傾向の強いMn
、Cr 、Mo 、Vを適切な量に抑え、更にSi含
有量を低下させパーライト化促進元素としてSnを目標
硬度に応じて適当量含有させることにより、通常のパー
2イト地球状黒鉛鋳鉄に比べて組織及び機械的性質のば
らつきが少ない極めて有用パーライト地球状黒鉛鋳鉄を
得ることができるものである。As is clear from the above explanation, Mn has a strong tendency to form carbides.
By suppressing , Cr, Mo, and V to appropriate amounts, and further reducing the Si content and containing an appropriate amount of Sn as a pearlitization promoting element according to the target hardness, it has a higher This makes it possible to obtain extremely useful pearlitic terrestrial graphite cast iron with little variation in structure and mechanical properties.
第1図及び第2図は本発明による板厚1101n及び7
0mmの顕微鏡組織第3図及び第4図は従来の板厚10
mm及び70mmの顕微鏡組織を示す写真である。Figures 1 and 2 show plate thicknesses of 1101n and 7 according to the present invention.
0mm microscopic structure Figures 3 and 4 are for conventional plate thickness 10mm.
It is a photograph showing microscopic structures of mm and 70 mm.
Claims (1)
n0.025〜0.20%、Mg 0.02〜0.0
8%とし残部Fe及びMn、Cr、V、Moなどの不純
物よりなることを特徴とする鋳放しパーライト地球状黒
鉛鋳鉄。 2 Mn含有量を0.30%以下とする特許請求の範
囲第1項記載の鋳放しパーライト地球状黒鉛鋳鉄。 3 Cr<0.10%、 Cu<0.20 %、V<
0.10%Mo < 0.25%とする特許請求の範囲
第1項または第2項に記載の鋳放しパーライト地球状黒
鉛鋳鉄。 4 Cr、Cu、V、Moの総和を0.50%以下と
する特許請求の範囲第1項ないし第3項のいずれかに記
載の鋳放しパーライト地球状黒鉛鋳鉄。[Claims] IC3-4.2%, S i 1.3-2.2%, S
n0.025-0.20%, Mg 0.02-0.0
As-cast pearlite terrestrial graphite cast iron, characterized in that the balance is 8% Fe and impurities such as Mn, Cr, V, and Mo. 2. The as-cast pearlite terrestrial graphite cast iron according to claim 1, wherein the Mn content is 0.30% or less. 3 Cr<0.10%, Cu<0.20%, V<
The as-cast pearlite terrestrial graphite cast iron according to claim 1 or 2, wherein 0.10%Mo<0.25%. 4. The as-cast pearlite terrestrial graphite cast iron according to any one of claims 1 to 3, wherein the sum of Cr, Cu, V, and Mo is 0.50% or less.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP1240177A JPS5917184B2 (en) | 1977-02-09 | 1977-02-09 | As-cast pearlite terrestrial graphite cast iron |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP1240177A JPS5917184B2 (en) | 1977-02-09 | 1977-02-09 | As-cast pearlite terrestrial graphite cast iron |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS5397919A JPS5397919A (en) | 1978-08-26 |
JPS5917184B2 true JPS5917184B2 (en) | 1984-04-19 |
Family
ID=11804231
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP1240177A Expired JPS5917184B2 (en) | 1977-02-09 | 1977-02-09 | As-cast pearlite terrestrial graphite cast iron |
Country Status (1)
Country | Link |
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JP (1) | JPS5917184B2 (en) |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS55164055A (en) * | 1979-06-08 | 1980-12-20 | Toyota Motor Corp | Spherical graphite cast iron for surface quenching |
FR2493191A1 (en) * | 1980-10-31 | 1982-05-07 | Usinor | CASTING COLD ROLLING CYDINDER AND MANUFACTURING METHOD THEREOF |
JP2624886B2 (en) * | 1990-09-19 | 1997-06-25 | 株式会社日立製作所 | Elevator equipment |
CN108193128A (en) * | 2018-02-24 | 2018-06-22 | 焦作固德联合机械制造有限公司 | A kind of high tenacity concrete pumps bend pipe casting method |
-
1977
- 1977-02-09 JP JP1240177A patent/JPS5917184B2/en not_active Expired
Also Published As
Publication number | Publication date |
---|---|
JPS5397919A (en) | 1978-08-26 |
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