JP2613612B2 - Graphite cast steel - Google Patents
Graphite cast steelInfo
- Publication number
- JP2613612B2 JP2613612B2 JP63029314A JP2931488A JP2613612B2 JP 2613612 B2 JP2613612 B2 JP 2613612B2 JP 63029314 A JP63029314 A JP 63029314A JP 2931488 A JP2931488 A JP 2931488A JP 2613612 B2 JP2613612 B2 JP 2613612B2
- Authority
- JP
- Japan
- Prior art keywords
- graphite
- less
- cast steel
- steel
- 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.)
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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】 （技術分野） 本発明は黒鉛鋳鋼に係り、特に鋳造のままで、被削性
と機械的性質（延性）に優れた黒鉛鋳鋼の特性の改善に
関するものである。Description: TECHNICAL FIELD The present invention relates to a graphite cast steel, and more particularly to an improvement in characteristics of a graphite cast steel having excellent machinability and mechanical properties (ductility) as cast.
（背景技術） 従来から、塑性加工や切削加工等を容易とするため
に、鋳鋼の内部に球場黒鉛を析出させた黒鉛鋼乃至は黒
鉛鋳鋼が知られている。ところで、そのような黒鉛を鋳
鋼中に析出させるには、黒鉛鋼では黒鉛化熱処理を施せ
ば良いが、鋳鋼においても同様な熱処理により黒鉛を析
出させようとすると、その熱処理に長時間を要し、しか
も析出した黒鉛が粗大で、形状が球状とならないため
に、熱処理では所期の目的を達成するのが難しいとされ
ている。尤も、鋳鋼に対しては、溶製時にマグネシウ
ム，カルシウム等を接種すると、鋳造のままで球状黒鉛
を鋳物中に生成させることが出来るが、球状黒鉛の分布
が均一ではなく、しかも析出した黒鉛粒径が大きいた
め、被削性の製品特性は充分に満足し得るものではなか
ったのである。(Background Art) Conventionally, graphite steel or graphite cast steel in which spherical graphite is precipitated inside cast steel in order to facilitate plastic working, cutting work and the like has been known. By the way, in order to precipitate such graphite in cast steel, it is only necessary to perform a graphitization heat treatment on graphite steel.However, if a similar heat treatment is to be performed on cast steel, the heat treatment requires a long time. Further, it is said that it is difficult to achieve the intended purpose by heat treatment because the precipitated graphite is coarse and does not become spherical in shape. However, when cast steel is inoculated with magnesium, calcium, etc. during smelting, spheroidal graphite can be formed in the casting as cast, but the distribution of spheroidal graphite is not uniform, and the precipitated graphite particles Due to the large diameter, the machinability product characteristics were not sufficiently satisfactory.
このため、本発明者らは、先に、特開昭61−248284号
として、溶製時に希土類元素の接種を行なう改善策を提
案し、これによって、鋳造のままで、微細な球状黒鉛が
鋳物中に均一に析出，分布した、被削性と機械的性質に
優れた鋳鋼を得ることが出来ることとなった。For this reason, the present inventors have previously proposed, as Japanese Patent Application Laid-Open No. 61-248284, an improvement measure for inoculating a rare earth element at the time of smelting. It has become possible to obtain cast steel having excellent machinability and mechanical properties uniformly precipitated and distributed therein.
ところが、本発明者らの更なる研究の結果、このよう
な、従来の黒鉛鋳鋼に比べて優れた特性を有する快削黒
鉛鋳鋼にあっては、マンガン、クロム等の炭化物形成元
素を添加して、その強度を向上せしめようとした場合に
おいて、析出黒鉛が粗大且つ不均一となる問題を生じる
ことが明らかとなったのである。However, as a result of further research by the present inventors, such free-cutting graphite cast steel having excellent properties as compared to conventional graphite cast steel, manganese, a carbide-forming element such as chromium is added. It has been clarified that when the strength is to be improved, a problem that the deposited graphite is coarse and non-uniform occurs.
（解決課題） ここにおいて、本発明は、上記の事情を背景にして為
されたものであって、その解決すべき課題とするところ
は、先に提案した快削黒鉛鋳鋼の優れた特性を損なうこ
となく、換言すれば鋳造のままで、微細且つ均一な球状
黒鉛が析出せしめられるようにすると共に、かかる鋳鋼
の強度を向上せしめようとすることにある。(Problem to be Solved) Here, the present invention has been made in view of the above circumstances, and the problem to be solved is to impair the excellent characteristics of the free-cutting graphite cast steel proposed earlier. In other words, in other words, it is to make fine and uniform spheroidal graphite precipitate as cast and to improve the strength of the cast steel.
（解決手段） そして、本発明は、かかる課題解決のために、重量基
準で、0.45〜2.0％の炭素（Ｃ）、1.0〜3.2％のケイ素
（Si）、0.01〜1.0％の希土類元素（REM）を含み、且つ
0.005〜0.400％のカルシウム（Ca）及び0.005〜0.400％
のマグネシウム（Mg）のうちの１種若しくは２種を含む
と共に、更に0.3％を越え、2.0％以下のマンガン（M
n）、0.1％を越え、1.0％以下のクロム（Cr）、0.01％
を越え、1.0％以下のモリブテン（Mo）、0.01％を越
え、0.5％以下のタングステン（Ｗ）、0.01％を越え、
0.5％以下のバナジウム（Ｖ）、0.01％を越え、0.5以下
のニオブ（Nb）、及び0.015％を越え、0.5％以下のチタ
ン（Ti）のうちの１種若しくは２種以上を含む、残部が
鉄（Fe）及び不可避的不純物からなる、黒鉛平均粒径が
3.0μｍ以下の、被削性と延性に優れた黒鉛鋳鋼を、そ
の要旨とするものである。(Solution) In order to solve this problem, the present invention provides, on a weight basis, carbon (C) of 0.45 to 2.0%, silicon (Si) of 1.0 to 3.2%, and rare earth element (REM) of 0.01 to 1.0%. ) And
0.005-0.400% calcium (Ca) and 0.005-0.400%
Containing one or two of magnesium (Mg), and further containing more than 0.3% and not more than 2.0% of manganese (Mg).
n), more than 0.1% and less than 1.0% chromium (Cr), 0.01%
More than 1.0% or less molybdenum (Mo), more than 0.01%, less than 0.5% tungsten (W), more than 0.01%,
0.5% or less of vanadium (V), more than 0.01%, less than 0.5 of niobium (Nb), and more than 0.015% and less than 0.5% of titanium (Ti) Graphite composed of iron (Fe) and unavoidable impurities has an average particle size of
The object of the present invention is to provide a cast graphite steel having excellent machinability and ductility of 3.0 μm or less.
このように、本発明にあっては、鋳造のままで、極め
て微細且つ均一な球状黒鉛を析出せしめるべく、REMを
添加する一方、強度を向上させるために添加されるMn,C
r等の炭化物形成元素によって惹起される析出黒鉛の粗
大化、不均一化を、CaやMgの添加により防止するように
したのである。即ち、黒鉛鋳鋼においては、析出黒鉛が
微細且つ均一なもの程、同じ引張強さにおいて比較する
と、延性、被削性が良好となるのであり、それ故、本発
明において、炭化物形成元素とCa,Mgを添加することに
より、黒鉛平均粒径を3.0μｍ以下と為し、以てより高
強度で、しかも延性、被削性の優れた黒鉛鋳鋼を製造す
ることが出来たのである。As described above, in the present invention, REM is added in order to precipitate extremely fine and uniform spheroidal graphite as cast, while Mn and C are added in order to improve the strength.
The addition of Ca and Mg prevents the coarsening and non-uniformity of precipitated graphite caused by carbide-forming elements such as r. That is, in graphite cast steel, the more fine and uniform the precipitated graphite, the better the ductility and machinability when compared at the same tensile strength.Therefore, in the present invention, the carbide forming element and Ca, By adding Mg, the graphite average particle size was reduced to 3.0 μm or less, and thus a graphite cast steel having higher strength and excellent ductility and machinability could be produced.
ところで、かかる本発明に従う快削黒鉛鋳鋼の各合金
成分の作用並びにその含有量の限定理由は、以下の通り
である。なお、以下に示される百分率は、何れも重量を
基準とするものである。By the way, the action of each alloy component of the free-cutting graphite cast steel according to the present invention and the reason for limiting the content thereof are as follows. In addition, the percentages shown below are all based on weight.
C:0.45〜2.0％ この元素は、鋳鋼中の黒鉛生成に不可欠な元素であ
り、その下限値（0.45％）に満たない含有量では、球状
黒鉛の析出量が少なく、黒鉛による被削性向上効果が充
分でない。また、上限値（2.0％）を越えるようになる
と、網目状黒鉛が析出して、機械的性質が低下し、好ま
しくない。C: 0.45 to 2.0% This element is indispensable for the formation of graphite in cast steel. If its content is less than the lower limit (0.45%), the precipitation amount of spheroidal graphite is small and machinability is improved by graphite. The effect is not enough. On the other hand, if it exceeds the upper limit (2.0%), reticulated graphite precipitates and mechanical properties are deteriorated, which is not preferable.
Si:1.0〜3.2％ Siは黒鉛の析出を促進する。その含有量が1.0％未満
では、その効果が小さく、黒鉛析出量が少ない。一方、
3.2％を越える含有量では、鋳鋼の硬度が増大し、延性
が著しく低下する問題を惹起する。Si: 1.0 to 3.2% Si promotes the precipitation of graphite. If the content is less than 1.0%, the effect is small and the amount of graphite deposition is small. on the other hand,
If the content exceeds 3.2%, the hardness of the cast steel increases, causing a problem that ductility is significantly reduced.
REM:0.01〜1.0％ REMとしては、原子番号57のLaから原子番号71のLuま
での元素を指し、この１種または２種以上が用いられる
こととなるが、そのようなREMは黒鉛の析出を促す元素
である。そして、その効果は、0.01％程度の低い含有量
から認められ、0.1〜1.0％の範囲で充分に高められる。
しかし、1.0％を越えるような含有量になると、鋳物の
ヒケが大きく、割れが生じる恐れがある。REM: 0.01 to 1.0% REM refers to an element from La with an atomic number of 57 to Lu with an atomic number of 71, and one or more of these elements are used. Is an element that promotes And the effect is recognized from a low content of about 0.01%, and is sufficiently enhanced in the range of 0.1 to 1.0%.
However, when the content exceeds 1.0%, sink of the casting is large, and there is a possibility that cracks may occur.
Ca:0.005〜0.400％ Mg:0.005〜0.400％ これらの元素は、後述する炭化物形成元素を添加した
場合において惹起される、析出黒鉛の粗大化、不均一化
を防止する効果を有する。そして、その効果を充分に奏
せしめるためには、それら元素は、それぞれ、少なくと
も0.005％以上添加せしめる必要があるが、それら元素
を、その上限値の0.400％を越えて添加しても、その効
果は飽和するようになり、より以上の微細化効果を期待
することは困難となる。Ca: 0.005 to 0.400% Mg: 0.005 to 0.400% These elements have an effect of preventing coarsening and non-uniformity of precipitated graphite caused when a carbide forming element described later is added. And, in order to sufficiently exhibit the effect, it is necessary to add at least 0.005% or more of each of these elements. Becomes saturated, and it becomes difficult to expect a further miniaturization effect.
Mn:0.3％超,2.0％以下 Cr:0.1％超,1.0以下 Mo:0.01％超,1.0％以下 W:0.01％超,0.5％以下 V:0.01％超,0.5％以下 Nb:0.01％超,0.5％以下 Ti:0.015％超,0.5％以下 これらの元素は何れも炭化物形成元素であって、それ
ら元素の少なくとも１種の添加により、鋳鋼中に炭化物
を形成して、機械的性質、特に強度を向上せしめること
となるが、それら元素のそれぞれの下限値に満たない添
加では、その添加効果を充分に発揮することが出来な
い。また、これら元素をそれぞれの上限値以上含有する
ようになると、黒鉛の球状化を著しく阻害し、靭延性を
低下せしめる等の問題を惹起する。Mn: More than 0.3%, 2.0% or less Cr: More than 0.1%, 1.0 or less Mo: More than 0.01%, 1.0% or less W: More than 0.01%, 0.5% or less V: More than 0.01%, 0.5% or less Nb: More than 0.01%, 0.5% or less Ti: more than 0.015%, 0.5% or less These elements are all carbide forming elements, and when at least one of these elements is added, carbides are formed in the cast steel, and the mechanical properties, particularly the strength, However, if the addition of these elements is less than the lower limit of each of them, the effect of the addition cannot be sufficiently exhibited. Further, when these elements are contained in amounts exceeding the respective upper limits, spheroidization of graphite is remarkably inhibited, and problems such as reduction in toughness and ductility are caused.
（実施例） 以下に、本発明の幾つかの実施例を示し、本発明を更
に具体的に明らかにすることとするが、本発明が、その
ような実施例の記載によって、何等の制約をも受けるも
のでないことは、言うまでもないところである。(Examples) Hereinafter, some examples of the present invention will be shown to clarify the present invention more specifically. However, the present invention imposes some restrictions by the description of such examples. It goes without saying that you don't receive anything.
また、本発明には、以下の実施例の他にも、更には上
記の具体的記述以外にも、本発明の趣旨を逸脱しない限
りにおいて、当業者の知識に基づいて種々なる変更、修
正、改良等を加え得るものであることが、理解されるべ
きである。In addition, in addition to the following examples, the present invention, in addition to the above-described specific description, various changes, corrections, and modifications based on the knowledge of those skilled in the art without departing from the spirit of the present invention. It should be understood that improvements can be made.
先ず、下記第１表に示される合金成分からなる組成の
鋳鋼を、50kg誘導炉で溶製して、第１図（ａ）及び
（ｂ）に示される鋳造品を砂型鋳造し、次いで、その得
られた鋳造品を770℃×２時間の熱処理を施した後、空
冷した。そして、この得られた鋳造品について、それぞ
れ、切削試験及び引張試験を行なうと共に、顕微鏡観察
を行なった。なお、REMとしてはミッシュメタルを使用
した。また、No.1〜13は、本発明に従う鋳鋼であり、更
にＡ〜Ｄは、それぞれの本発明鋼に対応する引張強さを
有するように調整された比較鋼である。First, a cast steel having a composition comprising the alloy components shown in Table 1 below was melted in a 50 kg induction furnace, and a casting shown in FIGS. 1 (a) and 1 (b) was sand-cast. The obtained cast product was subjected to a heat treatment at 770 ° C. for 2 hours and then air-cooled. Then, the obtained cast product was subjected to a cutting test and a tensile test, respectively, and was observed under a microscope. In addition, misch metal was used as REM. Further, Nos. 1 to 13 are cast steels according to the present invention, and A to D are comparative steels adjusted to have tensile strengths corresponding to the respective steels of the present invention.
ところで、引張強さ及び伸びの試験方法は、第１図
（ａ）及び（ｂ）に示される如く、各鋳造品より、その
破線部分をJIS4号引張試験片として取り出し、それぞれ
の試験を行なった。また、切削能率に係る試験は、第１
図（ａ）及び（ｂ）に示される鋳造品の健全部のドリル
寿命試験によって行なった。より具体的には、工具とし
て、SKH51,φ５ストレートシャンクドリルを用い、送
り:0.1mm/rev、穴深さ:20mmにて、各鋳造品の工具寿命
と切削速度との関係を求め、比較鋼Ａの工具寿命が1000
mmとなる切削速度を基準（100）として、それに対する
各鋳造品の工具寿命が1000mmとなる切削速度の比を、切
削能率とした。By the way, as shown in FIGS. 1 (a) and 1 (b), the test methods for tensile strength and elongation were as follows: a broken line portion was taken out from each casting as a JIS No. 4 tensile test piece, and each test was performed. . In addition, the test related to cutting efficiency is the first
This was performed by a drill life test of a sound part of the cast product shown in FIGS. More specifically, using a SKH51, φ5 straight shank drill as a tool, at a feed of 0.1 mm / rev and a hole depth of 20 mm, the relationship between the tool life and cutting speed of each casting was determined, and the comparison steel Tool life of A is 1000
The cutting speed at which the tool life of each casting was 1000 mm was defined as the cutting efficiency, with the cutting speed at which mm was used as the reference (100).
得られた結果を、黒鉛平均粒径と共に、下記第２表に
示す。The results obtained are shown in Table 2 below together with the average graphite particle size.
かかる第１表と第２表の対比から明らかなように、本
発明鋼１と比較鋼Ａとは、60kg f/mm2級の引張強さに調
整されたものであり、また本発明鋼2,3,4と比較鋼Ｂと
は、70kg f/mm2級の引張強さに、更に、本発明鋼５と比
較鋼Ｃとは、80kg f/mm2級の引張強さに、そしてまた、
本発明鋼６〜13と比較鋼Ｄとは、90kg f/mm2級の引張強
さに、それぞれ調整されたものであるが、比較鋼A,B,C,
Dに比べて、本発明鋼１〜13にあっては、CaやMgの添加
効果によって、析出黒鉛の平均粒径が3.0μｍ以下の著
しく小さなものとなり、そして伸びや切削能率が著しく
向上されているのである。 As is clear from the comparison between Tables 1 and 2, the steel 1 of the present invention and the comparative steel A were adjusted to a tensile strength of 60 kg f / mm 2 class, and the steel 2 of the present invention , 3,4 and comparative steel B have a tensile strength of 70 kg f / mm 2 class, and steel 5 of the present invention and comparative steel C have a tensile strength of 80 kg f / mm 2 class, and ,
The inventive steels 6 to 13 and the comparative steel D were adjusted to a tensile strength of 90 kg f / mm 2 class, respectively, and the comparative steels A, B, C, and
Compared with D, in the steels 1 to 13 of the present invention, due to the effect of adding Ca and Mg, the average particle size of the precipitated graphite becomes significantly smaller than 3.0 μm, and the elongation and cutting efficiency are significantly improved. It is.
（発明の効果） 以上の説明から明らかなように、本発明に従う黒鉛鋳
鋼は、希土類元素の効果により、鋳造のままで、微細且
つ均一な球状黒鉛を析出せしめた快削黒鉛鋳鋼の強度
を、Mn,Cr等の炭化物形成元素の量により調整しつつ、C
a及び／又はMgの添加により黒鉛の析出状況（粒径，分
布）を改善して、その延製、被削性を向上せしめ得たも
のであり、換言すれば被削性や機械的性質を向上せしめ
つつ、強度特性を効果的に高め得たものであって、そこ
に、本発明の格別顕著な技術的意義が存するのである。(Effects of the Invention) As is clear from the above description, the graphite cast steel according to the present invention has the strength of a free-cut graphite cast steel in which fine and uniform spheroidal graphite is precipitated as it is cast by the effect of the rare earth element. While adjusting by the amount of carbide forming elements such as Mn and Cr, C
By adding a and / or Mg, the precipitation (particle size, distribution) of graphite was improved, and its production and machinability were improved. In other words, machinability and mechanical properties were improved. The strength characteristics can be effectively enhanced while being improved, and there is a remarkable technical significance of the present invention.
第１図（ａ）及び（ｂ）は、それぞれ、実施例におい
て、砂型鋳造された鋳造品の正面図及びその側面図を示
すものである。FIGS. 1 (a) and 1 (b) show a front view and a side view of a sand-cast casting in the embodiment, respectively.
Claims (1)
2％のケイ素、0.01〜1.0％の希土類元素を含み、且つ0.
005〜0.400％のカルシウム及び0.005〜0.400％のマグネ
シウムのうちの１種若しくは２種を含むと共に、更に0.
3％を越え、2.0％以下のマンガン、0.1％を越え、1.0％
以下のクロム、0.01％を越え、1.0％以下のモリブテ
ン、0.01％を越え、0.5％以下のタングステン、0.01％
を越え、0.5％以下のバナジウム、0.01％を越え、0.5％
以下のニオブ、及び0.015％を越え、0.5％以下のチタン
のうちの１種若しくは２種以上を含む、残部が鉄及び不
可避的不純物からなる、黒鉛平均粒径が3.0μｍ以下
の、被削性と延性に優れた黒鉛鋳鋼。(1) 0.45 to 2.0% of carbon, 1.0 to 3.
Containing 2% silicon, 0.01-1.0% rare earth element and
It contains one or two of 005 to 0.400% calcium and 0.005 to 0.400% magnesium, and further contains 0.1%.
More than 3%, less than 2.0% manganese, more than 0.1%, 1.0%
Less than chromium, more than 0.01%, less than 1.0% molybdenum, more than 0.01%, less than 0.5% tungsten, 0.01%
Over 0.5% of vanadium, over 0.01%, 0.5%
Machinability, containing one or more of the following niobium and titanium exceeding 0.015% and 0.5% or less, the balance consisting of iron and unavoidable impurities, and having an average graphite particle size of 3.0 μm or less Graphite cast steel with excellent ductility.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63029314A JP2613612B2 (en) | 1988-02-10 | 1988-02-10 | Graphite cast steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63029314A JP2613612B2 (en) | 1988-02-10 | 1988-02-10 | Graphite cast steel |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01205058A JPH01205058A (en) | 1989-08-17 |
| JP2613612B2 true JP2613612B2 (en) | 1997-05-28 |
Family
ID=12272758
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63029314A Expired - Fee Related JP2613612B2 (en) | 1988-02-10 | 1988-02-10 | Graphite cast steel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2613612B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5478523A (en) * | 1994-01-24 | 1995-12-26 | The Timken Company | Graphitic steel compositions |
| CN104532115A (en) * | 2014-12-31 | 2015-04-22 | 铜陵市经纬流体科技有限公司 | Hydrogen-embrittlement-resistant high-strength soft sealing sluice valve body and preparation method thereof |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5321030A (en) * | 1976-08-11 | 1978-02-27 | Toyo Chiyuukou Kk | Crushing balls |
| JPS61174358A (en) * | 1985-01-30 | 1986-08-06 | Toyota Motor Corp | Spheroidal graphite cast steel of high strength |
-
1988
- 1988-02-10 JP JP63029314A patent/JP2613612B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH01205058A (en) | 1989-08-17 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |