JPH0559486A - Steel for cold forging excellent in induction hardenability and fatigue property - Google Patents
Steel for cold forging excellent in induction hardenability and fatigue propertyInfo
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- JPH0559486A JPH0559486A JP24462691A JP24462691A JPH0559486A JP H0559486 A JPH0559486 A JP H0559486A JP 24462691 A JP24462691 A JP 24462691A JP 24462691 A JP24462691 A JP 24462691A JP H0559486 A JPH0559486 A JP H0559486A
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- fatigue
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- cold forgeability
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Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は冷間鍛造により塑性加工
した後、高周波焼入する機械構造用鋼に関し、詳細には
自動車の足廻り部品、例えば等速ジョイントのアウター
レース等に好適な高周波焼入性及び疲労特性に優れた冷
間鍛造用鋼に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to steel for machine structural use which is induction hardened after being plastically worked by cold forging, and in particular, high frequency suitable for undercarriage parts of automobiles such as outer races of constant velocity joints. The present invention relates to a steel for cold forging excellent in hardenability and fatigue characteristics.
【０００２】[0002]
【従来の技術】高周波焼入処理により最終品質を得るた
めの機械構造用鋼としては、Ｃ：0.40〜0.60％を含有す
る中炭素鋼が一般に用いられ、熱間鍛造によって塑性加
工されてきた。但し熱間鍛造だけでは鍛造品の寸法精度
が悪く、その後に重切削工程が必要であることから、寸
法精度が良くて切削量を軽減できる冷間鍛造が採用され
るようになってきている。一方この冷間鍛造では、圧延
鋼材の冷間鍛造性向上を目的として球状化焼鈍が施され
るものの、ＪＩＳ中炭素鋼の球状化焼鈍材では変形抵抗
が高く冷間鍛造工具寿命が問題視されており、また割れ
発生限界が低いため圧縮加工での材料割れが問題となっ
ている。2. Description of the Related Art A medium carbon steel containing C: 0.40 to 0.60% is generally used as a steel for machine structure for obtaining final quality by induction hardening, and has been plastically worked by hot forging. However, since the dimensional accuracy of the forged product is poor only by hot forging and a heavy cutting step is required after that, cold forging that has good dimensional accuracy and can reduce the cutting amount has been adopted. On the other hand, in this cold forging, spheroidizing annealing is performed for the purpose of improving the cold forgeability of the rolled steel, but the spheroidizing annealed material of JIS medium carbon steel has high deformation resistance and cold forging tool life is a problem. In addition, since the crack generation limit is low, material cracking during compression processing has become a problem.
【０００３】この様な問題に対して、高周波焼入性を確
保した上で球状化焼鈍された中炭素鋼の冷間鍛造性を改
良する技術が種々提案されている。例えば特公平１−３
８８４７号公報には低Ｓｉ，低Ｍｎによって冷間鍛造性
を向上させると共に、Ｃ，Ｂ，Ｔｉ，Ｃｒによって高周
波焼入性を確保する技術が開示されている。また特公平
２−４７５３６号公報には低Ｓｉ，低Ｍｎ，低Ｐ，低Ｎ
を必須要件としてさらにＡｌ，Ｏ量を極力低下せしめる
と共に、Ｃａによる脱酸を行なうことによって冷間鍛造
性を向上させ、且つＴｉ，Ｂ，Ｃ，Ｃｒの添加によって
高周波焼入性を確保する技術が開示されている。For such problems, various techniques have been proposed for improving the cold forgeability of medium carbon steel which is spheroidized and annealed while ensuring the induction hardenability. For example, Japanese Patent Fair 1-3
Japanese Patent No. 8847 discloses a technique of improving cold forgeability by low Si and low Mn and ensuring induction hardenability by C, B, Ti and Cr. Japanese Patent Publication No. 2-47536 discloses low Si, low Mn, low P, low N.
Is a technology that further reduces the amount of Al and O as essential requirements, improves the cold forgeability by performing deoxidation with Ca, and secures the induction hardenability by adding Ti, B, C and Cr. Is disclosed.
【０００４】しかしながら、上記の従来技術では変形抵
抗や割れ発生限界で評価される冷間鍛造性は向上するに
しても、高周波焼入された製品のねじり疲労強度及び転
動疲労寿命といった疲労特性は不十分であり、高周波焼
入性のみならず疲労特性にも優れた冷間鍛造用鋼が要望
されている。However, even though the cold forgeability, which is evaluated by the deformation resistance and the limit of crack generation, is improved in the above-mentioned prior art, the fatigue characteristics such as torsional fatigue strength and rolling fatigue life of the induction hardened product are not improved. There is a demand for a steel for cold forging that is insufficient and has excellent fatigue properties as well as induction hardenability.
【０００５】[0005]
【発明が解決しようとする課題】本発明は上記事情に着
目してなされたものであって、転動面を有する軸物製
品、特に等速ジョイントのアウターレースにおいて重要
な要求特性であるねじり疲労強度及び転動疲労寿命を向
上させ、なおかつ冷間鍛造性に優れた機械構造用鋼であ
る高周波焼入性及び疲労特性に優れた冷間鍛造用鋼を提
供しようとするものである。SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has a torsional fatigue strength which is an important required characteristic in a shaft product having a rolling surface, particularly in an outer race of a constant velocity joint. Another object of the present invention is to provide a cold forging steel having improved rolling fatigue life and excellent in cold forgeability, which is a steel for machine structural use, which is excellent in induction hardenability and fatigue characteristics.
【０００６】[0006]
【課題を解決するための手段】上記目的を達成した本発
明の冷間鍛造用鋼とは、Ｃ：0.4 〜0.6 ％，Ｓｉ：0.1
％以下，Ｍｎ：0.2 〜0.4 ％，Ｐ：0.015 ％以下，Ｓ：
0.005 〜0.015 ％，Ｃｒ：0.20〜0.50％，Ｍｏ：0.08〜
0.30％，Ｂ：0.0005〜0.0030％，Ｔｉ：0.02〜0.05％，
Ａｌ：0.01〜0.05％，Ｎ：0.006 ％以下，Ｏ：0.002 ％
以下を含有し、かつＣｒ＋Ｍｏ：0.30〜0.80％であり、
残部Ｆｅおよび不可避不純物からなることを要旨とする
ものである。The steel for cold forging according to the present invention which has achieved the above object is C: 0.4 to 0.6%, Si: 0.1.
% Or less, Mn: 0.2 to 0.4%, P: 0.015% or less, S:
0.005 to 0.015%, Cr: 0.20 to 0.50%, Mo: 0.08 to
0.30%, B: 0.0005 to 0.0030%, Ti: 0.02 to 0.05%,
Al: 0.01-0.05%, N: 0.006% or less, O: 0.002%
Contains the following, and Cr + Mo: 0.30 to 0.80%,
The gist is that the balance consists of Fe and unavoidable impurities.
【０００７】[0007]
【作用】本発明者らは低Ｓｉ，低Ｍｎ，低Ｐ，低Ｓ，低
Ｏによって球状化焼鈍材の冷間鍛造性の尺度である変形
抵抗を低下させ、割れ発生限界の増大を図った。そして
Ｂを添加した成分系において、ＣｒとＭｏの複合添加が
Ｃｒ＋Ｍｏ：0.30〜0.80％の範囲内であれば、冷間鍛造
性を阻害することなく、高周波焼入製品のねじり疲労強
度及び転動疲労寿命の向上を図ることができるとの知見
を得て、高周波焼入製品の疲労寿命に優れた冷間鍛造用
鋼を開発することに成功した。以下、本発明鋼の含有成
分および含有量について説明する。The present inventors reduced the deformation resistance, which is a measure of the cold forgeability of the spheroidized annealed material, by low Si, low Mn, low P, low S, and low O, and increased the crack initiation limit. .. Then, in the component system containing B, if the combined addition of Cr and Mo is within the range of Cr + Mo: 0.30 to 0.80%, the torsional fatigue strength and rolling of the induction hardened product are not impaired without impairing the cold forgeability. Based on the knowledge that the fatigue life can be improved, we have succeeded in developing a steel for cold forging that has excellent fatigue life for induction hardened products. Hereinafter, the components and contents of the steel of the present invention will be described.
【０００８】Ｃは含有量が0.4 ％未満では必要な最小硬
さが得られず、耐摩耗性が劣化し、一方0.6 ％を超える
と冷間鍛造性が著しく低下するばかりか、切削加工性や
研削加工性を劣化させる。従ってＣ含有量は0.4 〜0.6
％とした。Ｓｉは含有量が0.1 ％を超えると、球状化焼
鈍材の変形抵抗と割れ発生限界の冷間鍛造性を劣化させ
る。従ってＳｉ含有量は0.1 ％以下とした。Ｍｎは含有
量が0.2 ％未満では脱酸が不充分であり、一方0.4 ％を
超えて含有させると球状化焼鈍材の変形抵抗が著しく増
大する。従ってＭｎ含有量は0.2 〜0.4 ％とした。Ｐは
低Ｐ化することにより、球状化焼鈍材の変形抵抗の低下
と割れ発生限界の向上効果がある。含有量が0.015 ％を
超えるとこれらの効果は期待できない。従って、Ｐ含有
量は0.015 ％以下とした。When the content of C is less than 0.4%, the required minimum hardness cannot be obtained and the wear resistance is deteriorated. On the other hand, when it exceeds 0.6%, not only the cold forgeability is remarkably lowered but also the machinability and the machinability are deteriorated. It deteriorates the grinding processability. Therefore, the C content is 0.4 to 0.6.
%. If the Si content exceeds 0.1%, it deteriorates the deformation resistance of the spheroidized annealed material and the cold forgeability at the cracking limit. Therefore, the Si content is set to 0.1% or less. If the Mn content is less than 0.2%, deoxidation is insufficient, while if the Mn content exceeds 0.4%, the deformation resistance of the spheroidized annealed material remarkably increases. Therefore, the Mn content is set to 0.2 to 0.4%. By reducing the P content of P, the deformation resistance of the spheroidized annealed material is reduced and the crack generation limit is improved. If the content exceeds 0.015%, these effects cannot be expected. Therefore, the P content is set to 0.015% or less.
【０００９】Ｓは低Ｓ化することにより、球状化焼鈍材
の割れ発生限界を著しく向上させる効果がある。但し転
動面を有する軸物製品は、一般に冷間鍛造加工後にドリ
ル加工等の切削加工が施されるので、被削性の点からＳ
含有量の下限値は0.005 ％とし、冷間鍛造加工の割れ発
生限界の点から0.015 ％を上限とした。Ｃｒは球状化焼
鈍材の変形抵抗を著しく増大させることなく高周波焼入
性を向上させ、製品の疲労特性を向上させる元素であ
る。高周波焼入性と製品の疲労特性の向上から下限値は
0.20％とし、変形抵抗の著しい増大を避けるため上限値
は0.50％とした。Ｍｏは本発明鋼において重要な役割を
もつ元素である。即ち、冷間鍛造性を著しく阻害するこ
となく高周波焼入性を向上させ、さらに製品の疲労特性
を向上させる目的で添加される。その含有量が0.08％未
満ではこの効果が発揮されず、一方0.30％を超えると疲
労特性は向上するものの、球状化焼鈍材の変形抵抗を著
しく増大させ冷間鍛造が困難となる。従ってＭｏの含有
量は0.08〜0.30％とした。By reducing S, S has the effect of significantly improving the cracking limit of the spheroidized annealed material. However, a shaft product having a rolling surface is generally subjected to a cutting process such as a drilling process after the cold forging process.
The lower limit of the content was 0.005%, and 0.015% was the upper limit in view of the cracking limit of cold forging. Cr is an element that improves the induction hardenability without significantly increasing the deformation resistance of the spheroidized annealed material and improves the fatigue characteristics of the product. The lower limit is due to the improvement of induction hardenability and product fatigue characteristics.
The upper limit was 0.20% and 0.50% to avoid a significant increase in deformation resistance. Mo is an element that plays an important role in the steel of the present invention. That is, it is added for the purpose of improving the induction hardenability without significantly impairing the cold forgeability and further improving the fatigue property of the product. If the content is less than 0.08%, this effect is not exhibited. On the other hand, if it exceeds 0.30%, the fatigue properties are improved, but the deformation resistance of the spheroidized annealed material is significantly increased, and cold forging becomes difficult. Therefore, the content of Mo is set to 0.08 to 0.30%.
【００１０】尚Ｃｒ＋Ｍｏが0.30％未満の場合、冷間鍛
造性は良好であるが、高周波焼入により十分な有効硬化
層深さが得られないため製品の疲労特性が著しく劣化し
てしまう。またＣｒ＋Ｍｏが0.80％を超えると、圧延材
組織はフェライト，パーライトにベーナイトが生成した
組織となり、ベーナイトの生成は球状化焼鈍材の変形抵
抗を著しく増大させ、このことが複雑形状である等速ジ
ョイントのアウターレースの冷間鍛造を不可能にすると
いった問題が生じてくる。このことから、Ｃｒ＋Ｍｏ：
0.30〜0.80％とした。When Cr + Mo is less than 0.30%, the cold forgeability is good, but the sufficient hardened layer depth cannot be obtained by induction hardening, so that the fatigue property of the product is significantly deteriorated. When Cr + Mo exceeds 0.80%, the rolled material has a structure in which bainite is formed in ferrite and pearlite, and the formation of bainite remarkably increases the deformation resistance of the spheroidized annealed material. There will be problems such as making cold forging of outer races impossible. From this, Cr + Mo:
It was set to 0.30 to 0.80%.
【００１１】Ｂは高周波焼入性を確保するために含有さ
せるが、含有量が0.0005％未満では十分な効果が得られ
ず、一方0.0030％を超えて含有させても効果は飽和して
しまう。従ってＢ含有量は0.0005〜0.0030％とした。Ｔ
ｉはＢを含有させるにあたってはＮを固定するために必
要な元素である。含有量が0.02％未満ではこの効果は少
なく、一方0.05％を超えて含有させても効果はそれほど
上昇せず、しかもＴｉ系非金属介在物に起因して製品の
転動疲労寿命を劣化させることになる。従ってＴｉ含有
量は0.02〜0.05％とした。B is contained in order to secure the induction hardenability, but if the content is less than 0.0005%, a sufficient effect cannot be obtained, while if it exceeds 0.0030%, the effect is saturated. Therefore, the B content is set to 0.0005 to 0.0030%. T
i is an element necessary for fixing N when B is contained. If the content is less than 0.02%, this effect is small, while if it exceeds 0.05%, the effect does not increase so much, and the rolling fatigue life of the product is deteriorated due to Ti-based non-metallic inclusions. become. Therefore, the Ti content is 0.02 to 0.05%.
【００１２】Ａｌは結晶粒の微細化のために含有させる
元素である。含有量が0.01％未満ではこの効果は少な
く、一方0.05％を超えて含有させても効果は飽和してし
まう。従ってＡｌ含有量は0.01〜0.05％とした。Ｎは含
有量が過多になると変形抵抗を増大させ、割れ発生限界
も低下させるので0.006 ％以下とした。Ｏは含有量が0.
002 ％以上になると割れ発生限界を著しく低下させると
共に、アルミナ系非金属介在物量を増大させ、転動疲労
寿命を低下させる。従ってＯ含有量は0.002 ％以下とし
た。Al is an element contained for refining crystal grains. If the content is less than 0.01%, this effect is small, while if it exceeds 0.05%, the effect is saturated. Therefore, the Al content is set to 0.01 to 0.05%. If the N content is excessive, it increases the deformation resistance and also lowers the crack initiation limit, so the N content was made 0.006% or less. O content is 0.
When it is 002% or more, the cracking limit is significantly lowered, the amount of alumina-based nonmetallic inclusions is increased, and the rolling fatigue life is shortened. Therefore, the O content is set to 0.002% or less.
【００１３】[0013]
【００１４】表１に示す種々の成分組成材を48mmφ棒鋼
に圧延した。球状化焼鈍処理後、冷間鍛造性を調査する
ため46mmφ×69mmHの円柱試験片を作製し、端面拘束圧
縮試験から割れ発生限界と変形抵抗を求めた。変形抵抗
はひずみ1.08（圧縮率60％）での値を求めた。Various component compositions shown in Table 1 were rolled into 48 mmφ steel bars. After the spheroidizing annealing treatment, a 46 mmφ × 69 mmH columnar test piece was prepared to investigate the cold forgeability, and the crack initiation limit and deformation resistance were obtained from the end face constrained compression test. The deformation resistance was determined at a strain of 1.08 (compression rate 60%).
【００１５】また48mmφ球状化焼鈍材は、平行部25mmφ
にセレーションの付いたねじり疲労試験片と12mmφ×22
mmH の転動疲労試験片に加工し、ねじり試験片は20ＫＨ
ｚ，転動疲労試験片は200 ＫＨｚで高周波加熱を行った
のち水焼入れし、150 ℃で焼きもどし処理した。試験片
断面のＨｖ硬さ分布を測定し、Ｈｖ≧480 以上の深さを
有効硬化深さとした。The spheroidized annealed material of 48 mmφ has a parallel portion of 25 mmφ.
Torsional fatigue test piece with serration and 12mmφ × 22
Processed into a rolling fatigue test piece of mmH, the torsion test piece is 20KH
The z and rolling fatigue test pieces were subjected to high frequency heating at 200 KHz, water quenching, and tempering at 150 ° C. The Hv hardness distribution in the cross section of the test piece was measured, and the depth of Hv ≧ 480 or more was defined as the effective hardening depth.
【００１６】ねじり疲労試験は100cpmの正弦波トルク
（120 〜200kgf・m) を負荷し、繰り返し破断回数６×10
4 でのトルク値をねじり疲労強度とした。また転動疲労
試験は、２円筒形転動疲労試験機を用いて接触応力600k
gf/mm2, 回転数46000rpmの条件で試験し、累積破損率10
％（Ｌ10）の繰り返し回数を転動疲労強度とした。結果
は表２に示す。In the torsional fatigue test, a sine wave torque of 100 cpm (120 to 200 kgf · m) was applied, and the number of repeated fractures was 6 × 10.
The torque value at 4 was taken as the torsional fatigue strength. In addition, the rolling fatigue test was conducted using a 2 cylindrical rolling fatigue tester with a contact stress of 600k.
Tested under the conditions of gf / mm 2 and rotation speed 46000 rpm, cumulative damage rate 10
% (L 10 ) was defined as the rolling fatigue strength. The results are shown in Table 2.
【００１７】[0017]
【表１】 [Table 1]
【００１８】[0018]
【表２】 [Table 2]
【００１９】No. １〜18は本発明に係る成分組成の１つ
以上を満足しない場合の比較例であり、少なくとも冷間
鍛造性，高周波焼入性，疲労特性のいずれかに劣る。N
o. １，２，５は夫々ＪＩＳ規格Ｓ45Ｃ，Ｓ53Ｃ，Ｓ58
Ｃに相当する鋼である。No. ３はＣｒ＋Ｍｏの値が過少
の場合の比較例であり、No. ４は過多の場合の比較例で
ある。No. ３は同一Ｃ量のNo. ２と比較して冷間鍛造性
に優れるものの、転動疲労寿命に劣っている。一方No.
４は、No. ２と比較してねじり疲労強度と転動疲労寿命
に優れるものの、冷間鍛造性は著しく劣る。Nos. 1 to 18 are comparative examples when one or more of the component compositions according to the present invention are not satisfied, and at least any of cold forgeability, induction hardenability and fatigue properties is inferior. N
o. 1, 2 and 5 are JIS standards S45C, S53C and S58, respectively.
It is a steel equivalent to C. No. 3 is a comparative example when the value of Cr + Mo is too small, and No. 4 is a comparative example when the value is too large. No. 3 is superior in cold forgeability to No. 2 having the same C content, but inferior in rolling fatigue life. On the other hand, No.
No. 4 is excellent in torsional fatigue strength and rolling fatigue life as compared with No. 2, but cold forgeability is remarkably inferior.
【００２０】No. ６はＣが少な過ぎる場合の比較例であ
り、実施例であるNo.20 と比較して冷間鍛造性は同等以
上であるが、高周波焼入性に劣り、ねじり疲労強度及び
転動疲労寿命の疲労特性に劣る。No. ７はＣが多過ぎる
場合の比較例であり、実施例であるNo.24 と比較して疲
労特性は同等であるが冷間鍛造性に劣る。No. ８はＳｉ
が多過ぎる場合の比較例であり、実施例であるNo.21 と
比較して疲労特性は同等であるが冷間鍛造性に劣る。N
o. ９はＭｎが少な過ぎる場合の比較例であり、実施例
であるNo.21 と比較して変形抵抗に優れるものの疲労特
性に劣る。No. １０はＭｎが多過ぎる場合の比較例であ
り、疲労特性にやや優れるものの冷間鍛造性に劣る。No. 6 is a comparative example when the amount of C is too small, and the cold forgeability is equal to or higher than that of No. 20 which is an example, but the induction hardenability is poor and the torsional fatigue strength is low. And inferior rolling fatigue life fatigue characteristics. No. 7 is a comparative example in the case where the amount of C is too large, and the fatigue characteristics are the same as those of the example No. 24, but the cold forgeability is poor. No. 8 is Si
Is a comparative example when there is too much, and the fatigue properties are equivalent to those of the example No. 21, but the cold forgeability is poor. N
o.9 is a comparative example in the case where Mn is too small, and is superior in deformation resistance to the fatigue resistance as compared with No. 21 which is an example. No. 10 is a comparative example when the Mn content is too large, and although the fatigue characteristics are slightly excellent, the cold forgeability is inferior.
【００２１】No.11 はＰが多過ぎる場合の比較例であ
り、実施例であるNo.21 と比較して疲労特性は同等であ
るが冷間鍛造性に劣る。No.12 はＳが多過ぎる場合の比
較例であり、実施例であるNo.21 と比較して疲労特性は
同等であるが冷間鍛造性に劣る。No.13 はＢが少な過ぎ
る場合の比較例であり、実施例であるNo.21 と比較して
冷間鍛造性は同等であるが高周波焼入性が劣り、疲労特
性が著しく劣る。No.14 はＴｉが少な過ぎる場合の比較
例であってボロン窒化物が形成されており、実施例であ
るNo.21 と比較して高周波焼入性が劣化し、疲労特性が
著しく劣る。No.15 はＴｉが多過ぎる場合の比較例であ
ってＴｉの過剰添加によってＴｉ系介在物が生成され、
実施例であるNo.21 と比較して疲労特性とりわけ転動疲
労寿命が著しく劣る。No. 11 is a comparative example when the amount of P is too large, and the fatigue characteristics are the same as those of No. 21, which is an example, but the cold forgeability is poor. No. 12 is a comparative example when the S content is too large, and the fatigue properties are the same as those of the example No. 21, but the cold forgeability is poor. No. 13 is a comparative example when B is too small, and the cold forgeability is equivalent to that of No. 21 which is an example, but the induction hardenability is poor and the fatigue property is remarkably poor. No. 14 is a comparative example when Ti is too small, and boron nitride is formed, and the induction hardenability is deteriorated and fatigue properties are remarkably inferior as compared with No. 21 which is an example. No. 15 is a comparative example when there is too much Ti, and Ti-based inclusions are generated by excessive addition of Ti,
Fatigue properties, especially rolling fatigue life, are significantly inferior to those of No. 21 which is an example.
【００２２】No.16 はＡｌが少な過ぎる場合の比較例で
あり、結晶粒度が粗いため実施例であるNo.21 と比較し
て割れ発生限界の冷間鍛造性及び疲労特性が劣る。No.1
7 はＮが多過ぎる場合の比較例であって、実施例である
No.21 と比較して疲労特性はほぼ同等であるが、冷間鍛
造性は著しく劣る。No.18 はＯが多過ぎる場合の比較例
であり、鋼中の清浄度が劣るため実施例であるNo.21 と
比較して冷間鍛造性及び疲労特性が劣る。No. 16 is a comparative example in the case where the amount of Al is too small, and since the grain size is coarse, the cold forgeability at the limit of cracking and the fatigue properties are inferior to No. 21 which is an example. No.1
7 is a comparative example when N is too much, and is an example
Fatigue properties are almost the same as No. 21, but cold forgeability is significantly inferior. No. 18 is a comparative example when the O content is too large, and the cold forgeability and fatigue properties are inferior to No. 21 which is an example because the cleanliness in the steel is inferior.
【００２３】これに対して、No.19 〜24は本発明に係る
成分組成のすべてを満足する実施例であり、冷間鍛造
性，高周波焼入性，疲労特性のすべてに優れている。Ｃ
ｒ＋Ｍｏを適量添加したNo.19 は同一Ｃ量のNo. １と比
較して冷間鍛造性と共にねじり疲労強度及び転動疲労寿
命に優れている。No. 20，21，22はＣｒ量を一定にし
て、Ｍｏ添加量を増大させた実施例である。ねじり疲労
強度と転動疲労寿命が、Ｍｏの増大に伴って向上するこ
とを示している。またNo. 20，21，22は同一Ｃ量の No.
２と比較して冷間鍛造性、ねじり疲労強度及び転動疲労
寿命のいずれにおいても優れている。On the other hand, Nos. 19 to 24 are examples satisfying all of the component compositions according to the present invention and are excellent in all of cold forgeability, induction hardenability and fatigue characteristics. C
No. 19 with an appropriate amount of r + Mo added is superior in cold forgeability to torsional fatigue strength and rolling fatigue life compared to No. 1 with the same C content. Nos. 20, 21, and 22 are examples in which the Cr content was kept constant and the Mo addition amount was increased. It is shown that the torsional fatigue strength and the rolling fatigue life improve as Mo increases. In addition, Nos. 20, 21, and 22 have the same C content.
Excellent in cold forgeability, torsional fatigue strength and rolling contact fatigue life as compared with No. 2.
【００２４】No. 23は No.21のＣｒ添加量を高めた場合
の実施例である。No.23 と No.21の比較から適量のＣｒ
の増大は冷間鍛造性を阻害することなくねじり疲労強度
と転動疲労寿命を向上させていることがわかる。No. 24
は同一Ｃ量の No.５と比較して冷間鍛造性、ねじり疲労
強度及び転動疲労寿命のいずれにおいても優れている。No. 23 is an example in which the Cr addition amount of No. 21 is increased. Comparing No.23 and No.21, a proper amount of Cr
It can be seen that the increase in the value improves the torsional fatigue strength and rolling fatigue life without impairing the cold forgeability. No. 24
Are superior in cold forgeability, torsional fatigue strength and rolling contact fatigue life compared to No. 5 with the same C content.
【００２５】[0025]
【発明の効果】本発明は以上の様に構成されているの
で、冷間鍛造性に優れ、かつ高周波焼入された製品のね
じり疲労強度と転動疲労寿命に優れた鋼材を得ることが
でき、特に等速ジョイントのアウターレース用材料とし
て好適な高周波焼入性及び疲労特性に優れた冷間鍛造用
鋼が提供できることとなった。EFFECTS OF THE INVENTION Since the present invention is constituted as described above, it is possible to obtain a steel material which is excellent in cold forgeability and has excellent torsional fatigue strength and rolling fatigue life of an induction-hardened product. In particular, it has become possible to provide a cold forging steel excellent in induction hardenability and fatigue properties, which is suitable as a material for outer races of constant velocity joints.
Claims (1)
Ｍｎ：0.2 〜0.4 ％，Ｐ：0.015 ％以下，Ｓ：0.005 〜
0.015 ％，Ｃｒ：0.20〜0.50％，Ｍｏ：0.08〜0.30％，
Ｂ：0.0005〜0.0030％，Ｔｉ：0.02〜0.05％，Ａｌ：0.
01〜0.05％，Ｎ：0.006 ％以下，Ｏ：0.002 ％以下を含
有し、かつＣｒ＋Ｍｏ：0.30〜0.80％であり、残部Ｆｅ
および不可避不純物からなることを特徴とする高周波焼
入性及び疲労特性に優れた冷間鍛造用鋼。1. C: 0.4 to 0.6%, Si: 0.1% or less,
Mn: 0.2-0.4%, P: 0.015% or less, S: 0.005-
0.015%, Cr: 0.20 to 0.50%, Mo: 0.08 to 0.30%,
B: 0.0005 to 0.0030%, Ti: 0.02 to 0.05%, Al: 0.
01 to 0.05%, N: 0.006% or less, O: 0.002% or less, and Cr + Mo: 0.30 to 0.80% with the balance Fe
And a steel for cold forging excellent in induction hardenability and fatigue characteristics, which is characterized by comprising unavoidable impurities.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP24462691A JPH0559486A (en) | 1991-08-28 | 1991-08-28 | Steel for cold forging excellent in induction hardenability and fatigue property |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP24462691A JPH0559486A (en) | 1991-08-28 | 1991-08-28 | Steel for cold forging excellent in induction hardenability and fatigue property |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0559486A true JPH0559486A (en) | 1993-03-09 |
Family
ID=17121553
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP24462691A Pending JPH0559486A (en) | 1991-08-28 | 1991-08-28 | Steel for cold forging excellent in induction hardenability and fatigue property |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0559486A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1069201A2 (en) * | 1999-07-13 | 2001-01-17 | Daido Tokushuko Kabushiki Kaisha | Steel for induction hardening |
| DE19928775C2 (en) * | 1998-06-29 | 2001-10-31 | Nsk Ltd | Induction hardened roller bearing device |
| WO2012048917A1 (en) * | 2010-10-11 | 2012-04-19 | Schaeffler Technologies AG & Co. KG | Quenched and tempered steel, use thereof as bar material, threaded spindle, toothed rack, toothed rack elements and method for producing same |
| JP2012251184A (en) * | 2011-05-31 | 2012-12-20 | Sanyo Special Steel Co Ltd | Steel excellent in fatigue characteristic and toughness |
-
1991
- 1991-08-28 JP JP24462691A patent/JPH0559486A/en active Pending
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19928775C2 (en) * | 1998-06-29 | 2001-10-31 | Nsk Ltd | Induction hardened roller bearing device |
| US6332714B1 (en) | 1998-06-29 | 2001-12-25 | Nsk Ltd. | Induction-hardened rolling bearing device |
| EP1069201A2 (en) * | 1999-07-13 | 2001-01-17 | Daido Tokushuko Kabushiki Kaisha | Steel for induction hardening |
| EP1069201A3 (en) * | 1999-07-13 | 2002-01-16 | Daido Tokushuko Kabushiki Kaisha | Steel for induction hardening |
| WO2012048917A1 (en) * | 2010-10-11 | 2012-04-19 | Schaeffler Technologies AG & Co. KG | Quenched and tempered steel, use thereof as bar material, threaded spindle, toothed rack, toothed rack elements and method for producing same |
| US9267195B2 (en) | 2010-10-11 | 2016-02-23 | Schaeffler Technologies AG & Co. KG | Tempered steel |
| JP2012251184A (en) * | 2011-05-31 | 2012-12-20 | Sanyo Special Steel Co Ltd | Steel excellent in fatigue characteristic and toughness |
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