JPH0116886B2 - - Google Patents
Info
- Publication number
- JPH0116886B2 JPH0116886B2 JP1724280A JP1724280A JPH0116886B2 JP H0116886 B2 JPH0116886 B2 JP H0116886B2 JP 1724280 A JP1724280 A JP 1724280A JP 1724280 A JP1724280 A JP 1724280A JP H0116886 B2 JPH0116886 B2 JP H0116886B2
- Authority
- JP
- Japan
- Prior art keywords
- temperature
- cast iron
- molybdenum
- spheroidal graphite
- copper
- 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
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 13
- 229910001141 Ductile iron Inorganic materials 0.000 claims description 13
- 239000010949 copper Substances 0.000 claims description 13
- 229910052802 copper Inorganic materials 0.000 claims description 13
- 229910052750 molybdenum Inorganic materials 0.000 claims description 13
- 239000011733 molybdenum Substances 0.000 claims description 13
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical group [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 12
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 claims description 12
- 238000005279 austempering Methods 0.000 claims description 9
- 238000000034 method Methods 0.000 claims description 7
- 238000004519 manufacturing process Methods 0.000 claims description 6
- 229910001566 austenite Inorganic materials 0.000 claims description 5
- 238000005480 shot peening Methods 0.000 claims description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 4
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims description 3
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 3
- 229910052799 carbon Inorganic materials 0.000 claims description 3
- 229910052749 magnesium Inorganic materials 0.000 claims description 3
- 239000011777 magnesium Substances 0.000 claims description 3
- 229910052710 silicon Inorganic materials 0.000 claims description 3
- 239000010703 silicon Substances 0.000 claims description 3
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 claims description 2
- 229910052742 iron Inorganic materials 0.000 claims description 2
- 229910052748 manganese Inorganic materials 0.000 claims description 2
- 239000011572 manganese Substances 0.000 claims description 2
- 239000000463 material Substances 0.000 description 6
- 229910001018 Cast iron Inorganic materials 0.000 description 4
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 4
- 230000005540 biological transmission Effects 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 229910000831 Steel Inorganic materials 0.000 description 3
- 239000010959 steel Substances 0.000 description 3
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 2
- 238000005452 bending Methods 0.000 description 2
- 238000005266 casting Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 229910000734 martensite Inorganic materials 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- 230000000717 retained effect Effects 0.000 description 2
- 150000003839 salts Chemical class 0.000 description 2
- 229910052718 tin Inorganic materials 0.000 description 2
- QIJNJJZPYXGIQM-UHFFFAOYSA-N 1lambda4,2lambda4-dimolybdacyclopropa-1,2,3-triene Chemical compound [Mo]=C=[Mo] QIJNJJZPYXGIQM-UHFFFAOYSA-N 0.000 description 1
- 229910002549 Fe–Cu Inorganic materials 0.000 description 1
- 229910017116 Fe—Mo Inorganic materials 0.000 description 1
- 229910039444 MoC Inorganic materials 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 229910001563 bainite Inorganic materials 0.000 description 1
- 238000005255 carburizing Methods 0.000 description 1
- 238000005261 decarburization Methods 0.000 description 1
- 230000000376 effect on fatigue Effects 0.000 description 1
- 238000009661 fatigue test Methods 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 150000001247 metal acetylides Chemical class 0.000 description 1
- -1 molybdenum carbides Chemical class 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 229910000679 solder Inorganic materials 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 239000011135 tin Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Heat Treatment Of Articles (AREA)
- Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
Description
本発明は、球状黒鉛鋳鉄部品の製造方法に関す
る。
炭素、ケイ素、マンガン及びマグネシウムを含
有する通常の球状黒鉛鋳鉄を加熱してオーステナ
イト化した後、常温より高い所定温度に急冷して
該温度に所定時間保持する、いわゆるオーステン
パ処理を行なつて、耐面圧強度を高める試みは既
になされており、浸炭鋼部品の代替として自動車
の動力伝達用歯車等に使用されている。しかし、
この種鋳鉄材料は、耐疲労強度が劣るため、動力
伝達用歯車に使用する場合、寸法を増大する必要
があり、このことは、関連部の寸法増加の原因に
もなり、全体として重量及び価格の増大を招く欠
点がある。
通常の球状黒鉛鋳鉄に、モリブデン及び場合に
よつてはニツケル、錫、銅等の合金化元素を添加
して、オーステンパ処理を行なうことが特開昭49
−53115号により提案されている。この場合、モ
リブデンの添加量は0.10〜0.26％であり、ニツケ
ルは2.5％以下、好ましくは0.5〜2.5％、錫は0.03
〜0.2％、銅は0.3〜1.0である。このようにして得
られた球状黒鉛鋳鉄は、高い耐疲労強度を持つと
説明されているが、浸炭鋼と同等の性能は発揮し
得ず、動力伝達用歯車のような高い耐面圧強度、
耐疲労強度及び耐焼付性が要求される用途に使用
することはできない。
したがつて、本発明は、すぐれた耐面圧強度、
耐疲労強度及び耐焼付性を持ち、動力伝達用歯車
等にも満足に使用することのできる球状黒鉛鋳鉄
部品の製造方法を提供することを目的とする。
本発明による球状黒鉛鋳鉄部品の製造方法は、
重量比で、炭素2.6〜4.0％、ケイ素1.5〜3.5％、
マンガン0.1〜1.0％、モリブデン0.03〜0.09％、
銅0.3〜1.5％、マグネシウム0.02〜0.10％、残部
が実質的に鉄からなる球状黒鉛鋳鉄を用いる。上
記組成よりなる鋳鉄部品は、850〜1000℃の温度
でこれを加熱し４時間以内該温度に保持してオー
ステナイト化した後に、220〜260℃に急冷して、
該温度で30分以上保持するオーステンパ処理が施
される。このオーステンパ処理の後、該部品には
さらにシヨツトピーニングが行なわれる。
本発明の方法において用いられる球状黒鉛鋳鉄
の組成は、銅及びモリブデンの添加を除いては通
常の球状黒鉛鋳鉄におけると同一であり、重量比
で0.04％以下の硫黄及び0.2％以下のリンを含む
ことができる。銅及びモリブデンを複合添加する
ことにより、耐疲労強度を大巾に高めることがで
きる。銅はパーライト化を促進する元素であり、
（Fe―Cu）3Cの形で基地中に均一分散する性質を
有するが、添加量が1.5％以上になると、結晶粒
界に偏析し、機械的性質たとえば耐面圧強度を低
下させる原因になる。モリブデンも、銅と同様
に、（Fe―Mo）3Cを形成するが、その添加量が
0.09％以上になると、板状のモリブデン炭化物が
形成される。この炭化物は、高硬度のものであ
り、耐面圧強度を高める効果があるが、疲労に対
しては著しい悪影響を及ぼす。また、モリブデン
は、炭化物を生成しない範囲、すなわち0.09％以
下では、基地中に均一に分布する性質があるが、
添加量がそれ以上になると、銅の場合と同様に粒
界近傍に偏析する性質がある。そして、オーステ
ンパ処理時のオーステナイト化温度でモリブデン
炭化物が一部分解し、微細黒鉛を形成する。この
ため、疲労寿命はさらに低下する。したがつて、
本発明においては、モリブデン添加量は0.09％以
下とする。
本発明の方法において、オーステナイト化後の
処理温度を220〜260℃とする理由は、この温度に
保持することにより、高硬度のベイナイト地が得
られるからである。処理温度が220℃以下であれ
ば、マルテンサイトが発生し始めるため、脆化す
る。したがつて、引張強さ及び疲労強度が共に低
下する。260℃以上では、十分な疲労強度が得ら
れない。処理温度が360℃以上になると、疲労強
度は比較的高くなるが、静的強度及び耐面圧強度
が低下する。本発明においては、上述の処理温度
で得られる高硬度表面にシヨツトピーニングを加
えることにより、すぐれた耐疲労強度を得ること
ができる。このように、硬質表面にシヨツトピー
ニングを行なうと、軟質表面に行なつた場合に比
べて、表面下に発生する圧縮応力は大きくなり、
かつ応力層も深くなるので、耐疲労強度の向上率
が比躍的に高められる。
すなわち、特定組成の鋳鉄部品と、特定の処理
との組合せによつて、高い耐面圧強度、高い耐疲
労強度をあわせて有する鋳鉄部品を製造すること
を特徴とする。上記組合せが特に優れている理由
としては、明確ではないが、オーステンパ処理後
の硬度を、銅添加の材料と、銅及びモリブデン添
加の材料とについて比較すると、両者間にほとん
ど差は認められないが、オーステンパ処理後の残
留オーステナイト量は、銅及びモリブデン添加の
材料における方が多くなる傾向にあり、残留オー
ステナイトのシヨツトピーニングによるマルテン
サイト化の効果も期待できる点があげられる。
尚、素材の溶解及び鋳造は通常の球状黒鉛鋳鉄の
製造方法と変るところはなく、モリブデン及び銅
の添加は、炉中又はトリベ添加でも後の性質に影
響は生じない。
実施例
別表に示す組成の球状黒鉛鋳鉄素材を鋳造によ
り製造し、被削性を良好にする目的で、920℃で
２時間、次いで750℃で２時間の加熱処理を行な
い、除冷した。
The present invention relates to a method for manufacturing spheroidal graphite cast iron parts. Ordinary spheroidal graphite cast iron containing carbon, silicon, manganese, and magnesium is heated to austenite, then rapidly cooled to a predetermined temperature higher than room temperature, and held at that temperature for a predetermined time, which is the so-called austempering treatment. Attempts have already been made to increase the surface pressure strength, and it is used in automobile power transmission gears and the like as a substitute for carburized steel parts. but,
This type of cast iron material has poor fatigue strength, so when used in power transmission gears, it is necessary to increase the dimensions, which also causes an increase in the dimensions of related parts, resulting in an overall increase in weight and cost. It has the disadvantage of causing an increase in Japanese Patent Laid-Open No. 49 Sho 49 proposed that ordinary spheroidal graphite cast iron be subjected to austempering treatment by adding alloying elements such as molybdenum and, in some cases, nickel, tin, and copper.
- Proposed by No. 53115. In this case, the amount of molybdenum added is 0.10-0.26%, nickel is 2.5% or less, preferably 0.5-2.5%, and tin is 0.03%.
~0.2%, copper 0.3-1.0. The spheroidal graphite cast iron obtained in this way is said to have high fatigue strength, but it does not have the same performance as carburized steel, and has a high surface pressure strength such as that used in power transmission gears.
It cannot be used in applications that require fatigue resistance and seizure resistance. Therefore, the present invention provides excellent surface pressure resistance,
The purpose of the present invention is to provide a method for manufacturing spheroidal graphite cast iron parts that have fatigue resistance and seizure resistance and can be satisfactorily used for power transmission gears and the like. The method for manufacturing spheroidal graphite cast iron parts according to the present invention includes:
By weight, carbon 2.6-4.0%, silicon 1.5-3.5%,
Manganese 0.1~1.0%, Molybdenum 0.03~0.09%,
Spheroidal graphite cast iron consisting of 0.3 to 1.5% copper, 0.02 to 0.10% magnesium, and the balance substantially iron is used. Cast iron parts having the above composition are heated at a temperature of 850 to 1000°C, held at that temperature for less than 4 hours to austenitize, and then rapidly cooled to 220 to 260°C.
Austempering treatment is performed by holding at this temperature for 30 minutes or more. After this austempering process, the part is further shot peened. The composition of the spheroidal graphite cast iron used in the method of the present invention is the same as that of ordinary spheroidal graphite cast iron, except for the addition of copper and molybdenum, and contains not more than 0.04% sulfur and not more than 0.2% phosphorus by weight. be able to. By adding copper and molybdenum in combination, fatigue strength can be greatly increased. Copper is an element that promotes pearlitization,
(Fe-Cu) has the property of being uniformly dispersed in the matrix in the form of 3C , but when the amount added exceeds 1.5%, it segregates at grain boundaries and causes a decrease in mechanical properties such as surface pressure resistance. Become. Like copper, molybdenum also forms (Fe-Mo) 3 C, but the amount added is
When the content exceeds 0.09%, plate-like molybdenum carbides are formed. This carbide has high hardness and has the effect of increasing surface pressure resistance, but has a significant negative effect on fatigue. In addition, molybdenum has the property of being uniformly distributed in the base in the range where it does not produce carbides, that is, 0.09% or less.
If the amount added is more than that, it tends to segregate near the grain boundaries as in the case of copper. Then, the molybdenum carbide is partially decomposed at the austenitizing temperature during the austempering treatment to form fine graphite. Therefore, the fatigue life is further reduced. Therefore,
In the present invention, the amount of molybdenum added is 0.09% or less. In the method of the present invention, the reason why the treatment temperature after austenitization is set to 220 to 260°C is that by maintaining this temperature, a highly hard bainite base can be obtained. If the processing temperature is below 220°C, martensite will begin to form, resulting in embrittlement. Therefore, both tensile strength and fatigue strength decrease. Sufficient fatigue strength cannot be obtained at temperatures above 260°C. When the treatment temperature is 360°C or higher, the fatigue strength becomes relatively high, but the static strength and surface pressure resistance strength decrease. In the present invention, excellent fatigue resistance can be obtained by adding shot peening to the high hardness surface obtained at the above-mentioned treatment temperature. In this way, when shot peening is performed on a hard surface, the compressive stress generated under the surface is greater than when shot peening is performed on a soft surface.
In addition, since the stress layer also becomes deeper, the rate of improvement in fatigue strength is dramatically increased. That is, the present invention is characterized by manufacturing cast iron parts having both high surface pressure resistance and high fatigue resistance by combining cast iron parts with a specific composition and a specific treatment. The reason why the above combination is particularly excellent is not clear, but when comparing the hardness after austempering of a material with copper added and a material with copper and molybdenum added, there is almost no difference between the two. The amount of retained austenite after austempering tends to be larger in materials to which copper and molybdenum are added, and the effect of converting retained austenite into martensite by shot peening can also be expected.
Note that the melting and casting of the material is no different from the ordinary manufacturing method of spheroidal graphite cast iron, and the addition of molybdenum and copper in the furnace or in the ladle does not affect the subsequent properties. Example A spheroidal graphite cast iron material having the composition shown in the attached table was produced by casting, and in order to improve machinability, it was heat treated at 920°C for 2 hours, then at 750°C for 2 hours, and then slowly cooled.
【表】
次いで、仕上げ寸法に機械加工を行なつた後、
オーステンパ処理を施した。オーステンパ処理
は、脱炭防止のため0.2〜0.3％のCO2を含む浸炭
性雰囲気のバツチ炉において行ない、920℃で70
分のオーステナイト化を行なつた後、あらかじめ
用意したKNO3とNaNO3の混合塩浴を含む低温
用ソルド炉に浸漬し、所定温度まで急冷後、２時
間恒温保持した。処理完了後、約80℃の温水で洗
浄し、乾燥後、シヨツトピーニングを以下の条件
により行なつた。
シヨツトサイズ 0.8mm鋼球
シヨツト時間 10分
アルメンゲージの変形が0.3〜0.4mmになるよう
に条件設定を行なう。
得られた試片を試験した結果、混合塩浴の温度
と引張強さとの間には、第１図に示すような関係
が認められた。また、小野式回転曲げ疲労テスタ
ーによる回転曲げ疲労試験の結果は第２図に示す
通りであり、本発明の方法により得られた試料
は、きわめてすぐれた耐疲労強度を示すことが認
められた。[Table] Next, after machining to the finished dimensions,
Austempered. The austempering treatment was carried out in a batch furnace with a carburizing atmosphere containing 0.2 to 0.3% CO2 to prevent decarburization, and was heated at 920℃ for 70℃.
After austenitizing for 20 minutes, the sample was immersed in a low-temperature solder furnace containing a mixed salt bath of KNO 3 and NaNO 3 prepared in advance, rapidly cooled to a predetermined temperature, and kept constant for 2 hours. After the treatment was completed, it was washed with warm water at about 80°C, dried, and shot peened under the following conditions. Shot size: 0.8mm steel ball Shot time: 10 minutes Set conditions so that the deformation of the Almen gauge is 0.3 to 0.4mm. As a result of testing the obtained specimens, a relationship as shown in FIG. 1 was observed between the temperature of the mixed salt bath and the tensile strength. Further, the results of the rotary bending fatigue test using the Ono type rotary bending fatigue tester are as shown in FIG. 2, and it was confirmed that the sample obtained by the method of the present invention exhibited extremely excellent fatigue resistance.
第１図はオーステナイト処理後の恒温保持温度
を引張強さとの関係を示す図表、第２図は恒温保
持温度と疲労強度との関係を示す図表である。
FIG. 1 is a chart showing the relationship between the constant temperature holding temperature after austenite treatment and tensile strength, and FIG. 2 is a chart showing the relationship between the constant temperature holding temperature and fatigue strength.
Claims (1)
％、マンガン0.1〜1.0％、モリブデン0.03〜0.09
％、銅0.3〜1.5％、マグネシウム0.02〜0.10％、
残部が実質的に鉄からなる球状黒鉛鋳鉄部品を、
850〜1000℃の温度で４時間以内加熱保持してオ
ーステナイト化した後に、220〜260℃に急冷し、
該温度で30分以上保持するオーステンパ処理を行
ない、次いで該部品にシヨツトピーニングを行な
うことを特徴とする球状黒鉛鋳鉄部品の製造方
法。1. Carbon 2.6-4.0%, silicon 1.5-3.5% by weight
%, manganese 0.1~1.0%, molybdenum 0.03~0.09
%, copper 0.3-1.5%, magnesium 0.02-0.10%,
Spheroidal graphite cast iron parts, the remainder of which is essentially iron,
After being heated and held at a temperature of 850 to 1000℃ for less than 4 hours to austenite, it is rapidly cooled to 220 to 260℃,
A method for manufacturing a spheroidal graphite cast iron part, which comprises performing an austempering treatment by holding the part at the temperature for 30 minutes or more, and then subjecting the part to shot peening.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1724280A JPS56116853A (en) | 1980-02-15 | 1980-02-15 | Manufacture of spherical graphite cast iron parts |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1724280A JPS56116853A (en) | 1980-02-15 | 1980-02-15 | Manufacture of spherical graphite cast iron parts |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS56116853A JPS56116853A (en) | 1981-09-12 |
| JPH0116886B2 true JPH0116886B2 (en) | 1989-03-28 |
Family
ID=11938472
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1724280A Granted JPS56116853A (en) | 1980-02-15 | 1980-02-15 | Manufacture of spherical graphite cast iron parts |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS56116853A (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59129730A (en) * | 1983-01-18 | 1984-07-26 | Toyota Motor Corp | Production of high strength crank shaft |
| JPS60121253A (en) * | 1983-12-05 | 1985-06-28 | Nissan Motor Co Ltd | Spheroidal graphite cast iron |
| JP2012117095A (en) * | 2010-11-30 | 2012-06-21 | Ud Trucks Corp | Method for improving fatigue strength of cast iron material |
| CN109706380A (en) * | 2019-01-04 | 2019-05-03 | 湖北宏伟成新型材料有限公司 | A kind of preparation method of CADI abrading-ball |
-
1980
- 1980-02-15 JP JP1724280A patent/JPS56116853A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS56116853A (en) | 1981-09-12 |
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