JPH04325624A - Austempering treatment for spheroidal graphite cast iron - Google Patents
Austempering treatment for spheroidal graphite cast ironInfo
- Publication number
- JPH04325624A JPH04325624A JP12291291A JP12291291A JPH04325624A JP H04325624 A JPH04325624 A JP H04325624A JP 12291291 A JP12291291 A JP 12291291A JP 12291291 A JP12291291 A JP 12291291A JP H04325624 A JPH04325624 A JP H04325624A
- Authority
- JP
- Japan
- Prior art keywords
- spheroidal graphite
- cast iron
- treatment
- graphite cast
- austenitizing
- 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.)
- Pending
Links
- 229910001141 Ductile iron Inorganic materials 0.000 title claims abstract description 21
- 238000005279 austempering Methods 0.000 title claims description 5
- 238000000034 method Methods 0.000 claims abstract description 8
- 230000009466 transformation Effects 0.000 claims abstract description 7
- 238000001816 cooling Methods 0.000 claims abstract description 3
- 238000005261 decarburization Methods 0.000 claims description 8
- 229910001566 austenite Inorganic materials 0.000 abstract description 9
- 229910001563 bainite Inorganic materials 0.000 abstract description 9
- 229910001562 pearlite Inorganic materials 0.000 abstract description 6
- 229910000859 α-Fe Inorganic materials 0.000 abstract description 4
- 239000011159 matrix material Substances 0.000 abstract description 3
- 229910001018 Cast iron Inorganic materials 0.000 abstract description 2
- 238000010438 heat treatment Methods 0.000 abstract description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 abstract 8
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 abstract 4
- 229910002804 graphite Inorganic materials 0.000 abstract 4
- 239000010439 graphite Substances 0.000 abstract 4
- 229910052742 iron Inorganic materials 0.000 abstract 4
- 238000005520 cutting process Methods 0.000 description 4
- 150000003839 salts Chemical class 0.000 description 3
- 239000002184 metal Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 238000010791 quenching Methods 0.000 description 2
- 230000000171 quenching effect Effects 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Landscapes
- Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
Abstract
Description
【0001】0001
【産業上の利用分野】本発明は、オーステンパーダクタ
イル鋳鉄の切削性を改善するオーステンバ処理法に関す
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an austempering process for improving the machinability of austempered ductile cast iron.
【0002】0002
【従来の技術】自動車部品や建設機械部品のように強度
を必要とする部品用材料として、安価な高強度鋳鉄であ
る球状黒鉛鋳鉄が多用されている。2. Description of the Related Art Spheroidal graphite cast iron, which is an inexpensive high-strength cast iron, is often used as a material for parts that require strength, such as automobile parts and construction machine parts.
【0003】この球状黒鉛鋳鉄の強度、靭性の向上を図
るため、焼入れによるオーステナイト組織をベイナイト
組織とするオーステンバ処理が成される。このオーステ
ンバ処理は、基本的には、たとえば、900℃前後で球
状黒鉛鋳鉄を焼入れ(約1時間)し、400〜450℃
、1時間条件の恒温保持をさせ、ベイナイト基地中にオ
ーステナイトを残留した組織とさせる。[0003] In order to improve the strength and toughness of this spheroidal graphite cast iron, an austenburizing process is performed to change the austenite structure by quenching into a bainite structure. This austempering treatment basically involves, for example, hardening spheroidal graphite cast iron at around 900°C (about 1 hour) and then heating it at 400 to 450°C.
, and kept at constant temperature for 1 hour to form a structure in which austenite remains in the bainite base.
【0004】残留オーステナイトの存在が、切削性を悪
くするため、切削を要する部品へのオーステンパーダク
タイル鋳鉄の利用拡大を困難としている。そこで、切削
性を向上させることを目的として、オーステナイトを完
全にベイナイト変態させることが考えられるが、しかし
、このための処理装置、処理制御が複雑で実用性という
面での改善が望まれている。The presence of retained austenite impairs machinability, making it difficult to expand the use of austempered ductile cast iron for parts that require machining. Therefore, it is considered to completely transform austenite into bainite in order to improve machinability, but the processing equipment and processing control for this are complex, and improvements in practicality are desired. .
【0005】[0005]
【発明が解決しようとする課題】本発明が解決しようと
する課題は、従来技術の前述不具合を解消させ、オース
テンパーダクタイル鋳鉄の切削性を向上させ、強度を必
要とする部品への利用を一層拡大させることにある。[Problems to be Solved by the Invention] The problems to be solved by the present invention are to eliminate the above-mentioned problems of the prior art, improve the machinability of austempered ductile cast iron, and further improve its use in parts requiring strength. It is about expanding.
【0006】[0006]
【課題を解決するための手段】本発明は、前述した課題
を解決するために、基本的には、オーステナイト化処理
に先立ち又は同時に球状黒鉛鋳鉄に対して脱炭層を作る
手段を用いる。[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention basically uses means for creating a decarburized layer in spheroidal graphite cast iron prior to or simultaneously with the austenitizing treatment.
【0007】より具体的には、本発明は、球状黒鉛鋳鉄
を脱炭雰囲気で熱処理すること、850〜950℃にて
焼入れした後恒温状態温度に保つこと、その後空冷する
ことよりなる球状黒鉛鋳鉄オーステンバ処理法を提供す
る。More specifically, the present invention provides spheroidal graphite cast iron by heat treating the spheroidal graphite cast iron in a decarburizing atmosphere, quenching it at 850 to 950°C, then keeping it at a constant temperature, and then cooling it in air. Provides an Austemper treatment method.
【0008】好ましくは、脱炭雰囲気が900〜950
℃、脱炭処理時間を3〜5時間、オーステナイト化時間
を30〜90分、恒温変態温度時間を30〜90分かつ
温度を300〜400℃とする。脱炭処理とオーステナ
イト化処理を同時に行なうことができる。[0008] Preferably, the decarburization atmosphere is 900 to 950
℃, the decarburization treatment time is 3 to 5 hours, the austenitization time is 30 to 90 minutes, the isothermal transformation temperature time is 30 to 90 minutes, and the temperature is 300 to 400℃. Decarburization treatment and austenitization treatment can be performed simultaneously.
【0009】オーステナイト化処理前又は同時の脱炭処
理をすると、球状黒鉛鋳鉄の表面が脱炭状態となり、オ
ーステナイト化処理によりこの脱炭状態は低Cで主とし
てフェライト地となりベイナイト化せず、パーライト地
となる。パーライト層は約0.15mmの深さとなり、
それ以外はオーステナイトがベイナイト組織に変態する
。パーライト化層は、切削性を向上させるので、約1.
5mmの切削量を要する部品に本発明は極めて有為であ
る。[0009] When decarburized before or at the same time as austenitization, the surface of spheroidal graphite cast iron becomes decarburized, and due to austenitization, this decarburized state becomes a low C, mainly ferritic, and does not become bainite, but becomes a pearlite. becomes. The pearlite layer is approximately 0.15mm deep,
In other cases, austenite metamorphoses into bainite structure. The pearlitized layer improves machinability, so approximately 1.
The present invention is extremely useful for parts that require a cutting amount of 5 mm.
【0010】0010
【実施例1】球状黒鉛鋳鉄として、Mg添加による球状
化処理したものを用いた。化学成分は、3.75%C、
2.75%Si、0.20%Mn、0.03%P、0.
008%S、0.025%Cr、0.040%Mgであ
る。[Example 1] As spheroidal graphite cast iron, one that had been subjected to spheroidization treatment by adding Mg was used. Chemical composition: 3.75%C,
2.75%Si, 0.20%Mn, 0.03%P, 0.
008% S, 0.025% Cr, and 0.040% Mg.
【0011】上記成分の球状黒鉛鋳鉄で、外径30φ×
長さ200mmの丸棒を鋳造しこれを共通の供試品とし
た。[0011] Spheroidal graphite cast iron with the above components, outer diameter 30φ×
A round bar with a length of 200 mm was cast and used as a common sample.
【0012】供試品1を900〜950℃に保った脱炭
雰囲気中に4時間保持して、外表面から約0.15mm
深さ迄に脱炭層(図1参照)を作った。[0012] Sample 1 was kept in a decarburizing atmosphere kept at 900 to 950°C for 4 hours, and about 0.15 mm from the outer surface was removed.
A decarburized layer (see Figure 1) was created up to the depth.
【0013】脱炭処理した供試品1を900〜950℃
の温度で、1時間焼入れ(オーステナイト化)し、続い
て、350℃にて1時間恒温状態とさせた。恒温状態を
塩浴により保持させた。その後空冷。[0013] Decarburized sample 1 was heated to 900 to 950°C.
It was quenched (austenitized) at a temperature of 350° C. for 1 hour, and then kept at a constant temperature of 350° C. for 1 hour. A constant temperature condition was maintained using a salt bath. Then air cooled.
【0014】恒温変態温度に保持した供試品1の表面は
、図2から明らかなように、脱炭層のフェライトがパー
ライト変態し、基地がオーステナイトからベイナイト組
織に変態しているAs is clear from FIG. 2, on the surface of specimen 1 maintained at a constant temperature transformation temperature, the ferrite in the decarburized layer is transformed to pearlite, and the matrix is transformed from austenite to bainite structure.
【0015】[0015]
【実施例2】実施例1に示した供試品と同一成分、同一
形状のものを供試品2とする。供試品2を、850〜1
000℃に保った脱炭雰囲気内で、3〜5時間脱炭オー
ステナイト化処理を行ない、続いて塩浴を用いて350
℃の恒温状態を1時間保持した。その後空冷した。[Example 2] A specimen with the same components and the same shape as the specimen shown in Example 1 was designated as specimen 2. Sample 2, 850-1
Decarburized austenitization treatment was carried out for 3 to 5 hours in a decarburized atmosphere maintained at 000°C, followed by 350°C decarburization using a salt bath.
A constant temperature state of 0.degree. C. was maintained for 1 hour. It was then air cooled.
【0016】供試品2の表面は、図2に示す如く、パー
ライト変態している。又、基地はオーステナイトからベ
イナイト組織に変態している。The surface of the sample 2 has been transformed into pearlite, as shown in FIG. In addition, the base is transformed from austenite to bainite structure.
【0017】[0017]
【比較例1】実施例1に示した供試品と同一成分、同一
形状のものを供試品3とした。供試品を900〜950
℃の温度で、1時間の焼入れ(オーステナイト化)をし
、塩浴を用い350℃にて、1時間の恒温処理し、オー
ステナイトをベイナイト組織に変態させた。[Comparative Example 1] A sample having the same components and the same shape as the sample shown in Example 1 was designated as sample 3. 900 to 950 samples
It was quenched (austenitized) at a temperature of 350° C. for 1 hour, and then subjected to constant temperature treatment at 350° C. for 1 hour using a salt bath to transform austenite into a bainite structure.
【0018】[0018]
【実験例】供試品1〜3の丸棒の外表面を、次の条件で
切削をした。
バイト 三菱HT:10
切込み 1.0mm
送り 0.2mm/回転回転数
600rpm[Experimental example] The outer surfaces of round bars of specimens 1 to 3 were cut under the following conditions. Bit Mitsubishi HT: 10 Depth of cut 1.0mm Feed 0.2mm/rotation speed
600rpm
【0019】供試品1と2は、供試品3に対し、同一バ
イトによる切削時間が約1.5倍早くなった。Samples 1 and 2 had cutting times approximately 1.5 times faster than sample 3 using the same cutting tool.
【0020】[0020]
【発明の効果】本発明による球状黒鉛鋳鉄のオーステン
バ処理を施したオーステンパーダクタイル鋳鉄に対する
切削性が向上すると共に、バイトの耐久性が良好となり
、バイトを5割近く長持ちさせ得る。Effects of the Invention According to the present invention, the machinability of spheroidal graphite cast iron on austempered ductile cast iron subjected to austempering treatment is improved, and the durability of the cutting tool is improved, making it possible to extend the tool life by nearly 50%.
【図1】供試品の外表面の脱炭層のフェライト組織を示
す金属組織である。FIG. 1 is a metal structure showing a ferrite structure of a decarburized layer on the outer surface of a specimen.
【図2】供試品の表面のパーライト組織を示す金属組織
である。FIG. 2 is a metal structure showing a pearlite structure on the surface of a sample.
Claims (3)
ること、850〜950℃にてオーステナイト化した後
恒温変態温度に保つこと、その後空冷することよりなる
球状黒鉛鋳鉄のオーステンバ処理法。1. A method for austenburizing spheroidal graphite cast iron, which comprises heat-treating spheroidal graphite cast iron in a decarburizing atmosphere, austenitizing it at 850 to 950°C, then maintaining it at a constant temperature transformation temperature, and then air cooling.
理時間を3〜5時間、オーステナイト化時間を30〜9
0分、恒温変態時間を30〜90分かつ温度を300〜
400℃としている請求項1の球状黒鉛鋳鉄のオーステ
ンバ処理法。2. Decarburization atmosphere: 900 to 950°C, decarburization treatment time: 3 to 5 hours, austenitization time: 30 to 9
0 minutes, isothermal transformation time 30-90 minutes and temperature 300-
The austempering method for spheroidal graphite cast iron according to claim 1, wherein the temperature is 400°C.
ト化処理を同時に行なう請求項1の球状黒鉛鋳鉄のオー
ステンバ処理法。3. The austenburizing method for spheroidal graphite cast iron according to claim 1, wherein the decarburization treatment and the austenitization treatment are performed simultaneously in a decarburization atmosphere.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP12291291A JPH04325624A (en) | 1991-04-26 | 1991-04-26 | Austempering treatment for spheroidal graphite cast iron |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP12291291A JPH04325624A (en) | 1991-04-26 | 1991-04-26 | Austempering treatment for spheroidal graphite cast iron |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH04325624A true JPH04325624A (en) | 1992-11-16 |
Family
ID=14847684
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP12291291A Pending JPH04325624A (en) | 1991-04-26 | 1991-04-26 | Austempering treatment for spheroidal graphite cast iron |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH04325624A (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH05112816A (en) * | 1991-05-24 | 1993-05-07 | Japan Small Corp | Production of adi product having good dimensional accuracy |
JPH07259966A (en) * | 1994-03-24 | 1995-10-13 | Zexel Corp | Housing for power transmission device and manufacture thereof |
-
1991
- 1991-04-26 JP JP12291291A patent/JPH04325624A/en active Pending
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH05112816A (en) * | 1991-05-24 | 1993-05-07 | Japan Small Corp | Production of adi product having good dimensional accuracy |
JPH07259966A (en) * | 1994-03-24 | 1995-10-13 | Zexel Corp | Housing for power transmission device and manufacture thereof |
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