JP5583352B2 - Induction hardening steel and induction hardening parts with excellent static torsional fracture strength and torsional fatigue strength - Google Patents

Induction hardening steel and induction hardening parts with excellent static torsional fracture strength and torsional fatigue strength Download PDF

Info

Publication number
JP5583352B2
JP5583352B2 JP2009035005A JP2009035005A JP5583352B2 JP 5583352 B2 JP5583352 B2 JP 5583352B2 JP 2009035005 A JP2009035005 A JP 2009035005A JP 2009035005 A JP2009035005 A JP 2009035005A JP 5583352 B2 JP5583352 B2 JP 5583352B2
Authority
JP
Japan
Prior art keywords
induction hardening
torsional
steel
strength
induction
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.)
Active
Application number
JP2009035005A
Other languages
Japanese (ja)
Other versions
JP2010189702A (en
Inventor
和明 福岡
邦和 冨田
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
JFE Bars and Shapes Corp
Original Assignee
JFE Bars and Shapes Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by JFE Bars and Shapes Corp filed Critical JFE Bars and Shapes Corp
Priority to JP2009035005A priority Critical patent/JP5583352B2/en
Publication of JP2010189702A publication Critical patent/JP2010189702A/en
Application granted granted Critical
Publication of JP5583352B2 publication Critical patent/JP5583352B2/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00Technologies related to metal processing
    • Y02P10/25Process efficiency

Description

本発明は高周波焼入れ用鋼および高周波焼入れ部品に関し、特に30KHz以下の周波数で高周波焼入れされる自動車および各種産業機器で使用されるシャフト等の軸状部品の素材として好適な鋼および該鋼を素材とする高周波焼入れ部品に関する。   TECHNICAL FIELD The present invention relates to induction hardening steel and induction hardening parts, and in particular, steel suitable as a material for shaft parts such as shafts used in automobiles and various industrial equipment induction hardened at a frequency of 30 KHz or less and the steel as a material. It relates to induction hardening parts.

自動車や産業機械で、高周波焼入れ・焼戻しを施して製造される部品のうち、静捩り破壊を起こしたり、捩り疲労破壊したりするものは、軸部を有する部品がほとんどである。   Of the parts manufactured by induction hardening and tempering in automobiles and industrial machines, most of the parts that cause static torsional fracture or torsional fatigue breakage have parts with shafts.

例えば、ドライブシャフト,アクスルシャフト,ステアリングシャフト,クランクシャフト等のシャフト部品や、モーターのシャフトや変速ギヤ用のシャフト等も相当する。   For example, shaft parts such as a drive shaft, an axle shaft, a steering shaft, and a crankshaft, a motor shaft, a transmission gear shaft, and the like also correspond.

近年、製品のコンパクト化に対応するため、部品類を高強度化してサイズを小さくする方法が取られており、これらの高周波焼入れ部品においても同様である。そのため、色々な手法で高強度化する対策が取られている。   In recent years, in order to cope with the downsizing of products, a method of increasing the strength of parts and reducing the size has been taken, and the same applies to these induction-hardened parts. Therefore, various measures are taken to increase the strength.

特許文献1は捩り疲労特性に優れた高周波焼入れ用鋼ならびに高周波焼入れ部品に関し、破壊の起点になると予想されるMnSの形状を制御し、さらに高周波焼入れのムラの原因となるフェライトの面積率と粒径を規定している。   Patent Document 1 relates to a steel for induction hardening and an induction hardening component having excellent torsional fatigue characteristics, controls the shape of MnS that is expected to be the starting point of fracture, and further, the ferrite area ratio and grains that cause unevenness in induction hardening. The diameter is specified.

特許文献2は高周波焼入れ部品に関し、衝撃曲げ特性および耐衝撃ねじり特性を向上させるため、高周波焼入れによる硬化深さを特定範囲に規定し、高周波焼入れ部組織をマルテンサイト率が90%以上の均一なマルテンサイト組織に規定することが記載されている。   Patent Document 2 relates to induction hardening parts, in order to improve impact bending characteristics and impact torsional characteristics, the hardening depth by induction hardening is specified within a specific range, and the induction hardening structure has a uniform martensite ratio of 90% or more. It describes that it is prescribed in the martensite organization.

特開2002−069566号公報JP 2002-069566 A 特開平10−36937号公報JP-A-10-36937

しかしながら、特許文献1記載の高周波焼入れ用鋼は、MnSの形状を変えるために希土類金属であるCa,Zr,Mg、Yのいずれかを添加しなければならず経済性と製造性が悪い。また、フェライト量は鋼中の炭素含有量と組織形成時の冷却速度が密接に関係してくるために、化学成分ごとに精密なコントロールが必要である。   However, in the induction hardening steel described in Patent Document 1, any of rare earth metals Ca, Zr, Mg, and Y must be added in order to change the shape of MnS, resulting in poor economy and manufacturability. Moreover, since the ferrite content is closely related to the carbon content in the steel and the cooling rate during the formation of the structure, precise control is required for each chemical component.

さらにフェライト粒微細化においてはフェライト核生成サイトの増大と均一分散が必要で、鍛造と圧延方法および微細析出物の析出状態をコントロールすることが必要であるが最適条件の選定は容易でない。   Further, in the refinement of ferrite grains, it is necessary to increase the number of ferrite nucleation sites and uniformly disperse them, and it is necessary to control the forging and rolling method and the precipitation state of fine precipitates, but it is not easy to select optimum conditions.

特許文献2記載の高周波焼入れ部品は、高周波焼入れした領域の板厚方向や径方向の深さと高周波焼入れして得られる組織とを所定のものとするため、部品形状に応じた高周波焼入条件を成分組成との関係において選定しなければならず、経済性と作業効率が低下する。   The induction-hardened component described in Patent Document 2 has a predetermined thickness and depth in the induction-hardened region and a structure obtained by induction hardening. It must be selected in relation to the component composition, and the economic efficiency and work efficiency are reduced.

そこで、本発明は、高周波焼入れ用鋼および前記鋼を素材とする静捩り破壊強度および捩り疲労強度に優れる部品を提供することを目的とする。   Then, an object of this invention is to provide the components which are excellent in the static torsion fracture strength and the torsional fatigue strength which use the steel for induction hardening and the said steel as a raw material.

本発明者等は、上記課題を解決するために、鋭意研究を行い、以下の知見を得た。
1.高周波焼入後に得られる、内部硬さと硬化層深さ、焼入れ部の結晶粒径を規定し、硬度分布を最適化することで、静捩り破壊強度と捩り疲労強度を向上させることが可能である。
2.高周波焼入れ前の鋼素材の組織をパーライト主体とすると、高周波焼入れによる硬化層の深さが安定し、且つ、高周波焼入れ・焼戻し後の硬さのバラツキを抑えることが可能となる。
In order to solve the above-mentioned problems, the present inventors conducted intensive research and obtained the following knowledge.
1. It is possible to improve static torsional fracture strength and torsional fatigue strength by prescribing the internal hardness, hardened layer depth and crystal grain size of the quenched part obtained after induction hardening and optimizing the hardness distribution. .
2. If the structure of the steel material before induction hardening is mainly pearlite, the depth of the hardened layer by induction hardening becomes stable, and it becomes possible to suppress variations in hardness after induction hardening and tempering.

本発明は以上の知見を基に更に検討を加えてなされたもので、すなわち、本発明は、1.質量%で、C:0.40〜0.55%、Si:0.05〜0.50%、Mn:0.60〜2.00%、P:0.030%以下、S:0.005〜0.060%、Cr:0.05〜0.50%、Mo:0.35%以下、B:0.0005〜0.0080%、Ti:0.010〜0.035%、N:0.0050〜0.0100%を含有し、残部Feおよび不可避的不純物からなる成分組成と、初析フェライト体積率が15%未満のパーライト主体のミクロ組織を備えることを特徴とする高周波焼入れ用鋼。
2.成分組成に、更に、質量%で、V:0.005〜0.4%、Nb:0.01〜0.10%の1種以上を含むことを特徴とする1記載の高周波焼入れ用鋼。
3.成分組成が、更に、下記(1)および(2)式を満足する事を特徴とする1または2に記載の高周波焼入れ用鋼。
0.80≦C+Si/7+Mn/5+Cr/9+Mo/2+V/2≦1.00 ・・・(1)
1.11≦0.36×C+0.18×Si+0.27×Mn+0.30×Cr+0.43×Mo+135×B+0.24≦1.31 ・・・(2)
これらの式において各元素は含有量(質量%)を示し、含有しない元素は0とする。
4.1乃至3の何れか一つに記載の高周波焼入れ用鋼を素材とし、圧延、鍛造若しくは機械加工またはそれらの組み合わせにより軸部を有する部品形状とした後、前記軸部を高周波焼入れ・焼戻しにより有効硬化層深さ/半径の比が0.4〜0.6、焼入れ部の結晶粒度は粒度7.0以上とした、静捩り破壊強度および捩り疲労強度に優れた高周波焼入れ部品。
5.更に、高周波焼入れ・焼戻しをした後の硬さ分布が、下記(3)式を満足することを特徴とする4に記載の静捩り破壊強度および捩り疲労強度に優れた高周波焼入れ部品。
The present invention has been made on the basis of the above findings and has been further studied. In mass%, C: 0.40 to 0.55%, Si: 0.05 to 0.50%, Mn: 0.60 to 2.00%, P: 0.030% or less, S: 0.005 -0.060%, Cr: 0.05-0.50%, Mo: 0.35% or less, B: 0.0005-0.0080%, Ti: 0.010-0.035%, N: 0 A steel for induction hardening characterized by comprising a component composition comprising .0050-0.0100%, the balance being Fe and inevitable impurities, and a microstructure of pearlite mainly having a proeutectoid ferrite volume fraction of less than 15%.
2. 2. The steel for induction hardening according to 1, wherein the component composition further includes one or more of V: 0.005 to 0.4% and Nb: 0.01 to 0.10% by mass%.
3. The steel for induction hardening according to 1 or 2, wherein the component composition further satisfies the following formulas (1) and (2):
0.80 ≦ C + Si / 7 + Mn / 5 + Cr / 9 + Mo / 2 + V / 2 ≦ 1.00 (1)
1.11 ≦ 0.36 × C + 0.18 × Si + 0.27 × Mn + 0.30 × Cr + 0.43 × Mo + 135 × B + 0.24 ≦ 1.31 (2)
In these formulas, each element indicates a content (mass%), and an element not included is 0.
After using the steel for induction hardening according to any one of 4.1 to 3 as a raw material to form a part having a shaft portion by rolling, forging, machining, or a combination thereof, the shaft portion is induction hardened and tempered. Thus, the induction hardened component having excellent static torsional fracture strength and torsional fatigue strength, in which the effective hardened layer depth / radius ratio is 0.4 to 0.6 and the crystal grain size of the quenched portion is 7.0 or more.
5. Furthermore, the induction hardened component having excellent static torsional fracture strength and torsional fatigue strength according to 4, wherein the hardness distribution after induction hardening and tempering satisfies the following formula (3):

6.高周波焼入れ・焼戻しを施した部分に、更に、ショットピーニングを行うことを特徴とする、4または5に記載の静捩り破壊強度および捩り疲労強度に優れた高周波焼入れ部品。 6). 4. The induction-hardened component having excellent static torsional fracture strength and torsional fatigue strength according to 4 or 5, wherein the part subjected to induction hardening and tempering is further subjected to shot peening.

本発明によれば、自動車,産業機械等で従来から使用されている、一般的には5KHz〜30KHzの高周波焼入れ・焼戻しの条件を変える事無く、優れた、静捩り破壊強度および捩り疲労特性を備えた部品を製造し、またその素材を提供する事が可能で産業上極めて有用である。   According to the present invention, excellent static torsional fracture strength and torsional fatigue characteristics have been used without changing the conditions of induction hardening and tempering that have been conventionally used in automobiles, industrial machines, etc., and generally from 5 KHz to 30 KHz. It is extremely useful industrially because it is possible to manufacture the parts provided and to provide the materials.

静捩り破壊試験用および捩り疲労試験用試験片の形状を示す図。The figure which shows the shape of the test piece for a static torsion fracture test and a torsional fatigue test.

本発明に係る高周波焼入れ用鋼は、成分組成と高周波焼入れ前のミクロ組織(熱間圧延後のミクロ組織)を規定する。
[成分組成]説明において%は質量%とする。
C:0.40〜0.55%
Cは高周波焼入れにおいて硬度確保のために必要で、高周波焼入れ・焼もどし後の表面硬さを決定する。また、高周波焼入れ前の圧延あるいは鍛造ままの状態における組織形成にも影響する。
The steel for induction hardening according to the present invention defines the component composition and the microstructure before induction hardening (the microstructure after hot rolling).
[Ingredient composition] In the description, “%” means “mass%”.
C: 0.40 to 0.55%
C is necessary for ensuring hardness in induction hardening, and determines the surface hardness after induction hardening and tempering. In addition, it affects the structure formation in the state of rolling or forging before induction hardening.

C含有量が0.40%に満たないと高周波焼入れ前組織がパーライト主体ではなく、フェライト・パーライト二相組織となり、フェライト分率が15%以上になるため、焼入れ深さのバラツキが大きくなるばかりでなく、高周波焼入れ・焼戻し後の表面硬さが低下して部品としての強度を確保できない。一方、0.55%を超えると焼入性が高くなりすぎるために、焼き割れが発生しやすくなるため、0.40〜0.55%とする。   If the C content is less than 0.40%, the structure before induction hardening is not pearlite, but a ferrite-pearlite two-phase structure, and the ferrite fraction is 15% or more, so that the variation in the quenching depth only increases. In addition, the surface hardness after induction hardening and tempering decreases, and the strength as a part cannot be secured. On the other hand, if it exceeds 0.55%, the hardenability becomes too high, so that cracks are likely to occur, so 0.40 to 0.55%.

Si:0.05〜0.50%
Siは脱酸元素である。Si添加量が0.05%未満の場合は脱酸の効果が十分得られず、内部に酸化物が残存して疲労強度が低下する。一方、0.50%を超えると硬さが上昇して靭性が低下するために静捩り破壊強度が低下するため、Si添加量は0.05〜0.50%とする。
Si: 0.05 to 0.50%
Si is a deoxidizing element. When the amount of Si added is less than 0.05%, a sufficient deoxidation effect cannot be obtained, and oxide remains in the interior, resulting in a decrease in fatigue strength. On the other hand, if it exceeds 0.50%, the hardness is increased and the toughness is lowered, so that the static torsional fracture strength is lowered. Therefore, the Si addition amount is made 0.05 to 0.50%.

Mn:0.60〜2.00%
Mnは焼入性を高める元素である。焼入性を確保するため、0.60%以上必要で、一方、2.00%を超えて添加すると、焼入性が高すぎて焼き割れを生じるため、Mn添加量は0.60〜2.00%とする。
Mn: 0.60 to 2.00%
Mn is an element that enhances hardenability. In order to ensure hardenability, 0.60% or more is necessary. On the other hand, if added over 2.00%, the hardenability is too high to cause quench cracking, so the Mn addition amount is 0.60-2. 0.000%.

P:0.030%以下
Pは粒界に偏析して粒界を脆化させる作用があり、0.030%を超えると顕著となるため、0.030%以下とする。不可避的不純物のため、製造コストに悪影響を与えない範囲で低減させることが望ましい。
P: 0.030% or less P has an action of segregating at the grain boundaries and embrittles the grain boundaries. When it exceeds 0.030%, it becomes remarkable, so 0.030% or less. Since it is an unavoidable impurity, it is desirable to reduce it within a range that does not adversely affect the manufacturing cost.

S:0.060%以下
SはMnと結合してMnSを形成し、切削性を向上させるが、過剰なMnSは焼入れ性を低下させ、捩り疲労での破壊起点となって疲労強度を低下させるため、0.060%以下とする。不可避的不純物のため、製造コストに悪影響を与えない範囲で低減させることが望ましい。
S: 0.060% or less S combines with Mn to form MnS and improves machinability. However, excessive MnS reduces hardenability and serves as a starting point for fracture in torsional fatigue, thus reducing fatigue strength. Therefore, it is made 0.060% or less. Since it is an unavoidable impurity, it is desirable to reduce it within a range that does not adversely affect the manufacturing cost.

Cr:0.05〜0.50%
Crは焼入性向上元素であり、その作用を得るため0.05%以上を添加する。一方、0.50%を超えると焼入性が高くなりすぎて焼き割れを起こしやすくなるため、0.05〜0.50%とする。
Cr: 0.05 to 0.50%
Cr is a hardenability improving element, and 0.05% or more is added to obtain its effect. On the other hand, if it exceeds 0.50%, the hardenability becomes too high and it is easy to cause a burning crack, so 0.05 to 0.50%.

Mo:0.35%以下
Moは焼入性向上元素であり、添加するが、0.35%を超えると、焼き割れが発生しやすくなるため0.35%以下とする。
Mo: 0.35% or less Mo is a hardenability-improving element and is added. However, if it exceeds 0.35%, a cracking is likely to occur, so the content is made 0.35% or less.

Ti:0.010〜0.035%
TiはNとの結合力が強く、Bよりも優先して結合し、Ti窒化物あるいはTi炭窒化物を形成する。Tiが0.010%未満の場合、固溶したNが残ってBNを形成して、Bの焼入れ性向上効果が得られない。一方、0.035%を超えて添加してもその効果は飽和するため、0.010〜0.035%とする。
Ti: 0.010 to 0.035%
Ti has a strong bonding force with N and is bonded in preference to B to form Ti nitride or Ti carbonitride. When Ti is less than 0.010%, solid solution N remains to form BN, and the effect of improving the hardenability of B cannot be obtained. On the other hand, even if added over 0.035%, the effect is saturated, so 0.010 to 0.035%.

B:0.0005〜0.0080%
Bは焼入性向上元素であり、高周波焼入れにおいて硬化層深さを増大させる。その効果を得るには0.0005%以上必要であるが、0.0080%を超えるとその効果は飽和するため0.0005〜0.0080%とする。
B: 0.0005 to 0.0080%
B is a hardenability improving element and increases the depth of the hardened layer in the induction hardening. To obtain this effect, 0.0005% or more is necessary. However, if it exceeds 0.0080%, the effect is saturated, so 0.0005 to 0.0080%.

N:0.0100%以下
Nは、Tiと結合してTiNを形成させ、焼入れ性に寄与する固溶Bの確保を行う必要がある。Nが高いとTiと結合出来ずに残留する固溶Nが存在し、Bと優先して結合するために固溶Bの確保が難しくなる。安定して固溶Bを確保するためにはNは0.0100%以下である必要がある。よって、N含有量は0.0100%以下とした。
N: 0.0100% or less N needs to be bonded to Ti to form TiN and to secure solid solution B that contributes to hardenability. When N is high, solid solution N that remains without being bonded to Ti exists and bonds with B preferentially, so that it is difficult to secure solid solution B. In order to ensure the solid solution B stably, N needs to be 0.0100% or less. Therefore, the N content is set to 0.0100% or less.

以上が本発明鋼の基本成分組成で、高周波焼入れ・焼戻し処理後において、優れた静捩り破壊強度および捩り疲労強度の部品が得られるが、更に、部品において静捩り破壊強度および捩り疲労強度を向上させる場合、Nb,Vの一種以上を添加する。   The above is the basic component composition of the steel of the present invention. After induction hardening and tempering, parts with excellent static torsional fracture strength and torsional fatigue strength can be obtained. When it is used, at least one of Nb and V is added.

また、下記(1)、(2)式のパラメータ式を満足するように成分設計を行うとNb,Vの一種以上を添加した場合より、更に、捩り疲労強度を向上させることが可能である。(1)、(2)式のパラメータ式の効果は基本成分組成においても、更に基本成分組成にNb、Vの一種以上を添加した場合と同様に得られる。   Moreover, when the component design is performed so as to satisfy the following parameter formulas (1) and (2), the torsional fatigue strength can be further improved as compared with the case where one or more of Nb and V are added. The effects of the parameter formulas (1) and (2) can be obtained in the basic component composition in the same manner as when one or more of Nb and V are added to the basic component composition.

Nb:0.01〜0.10%、V:0.0005〜0.4%の1種以上
NbおよびVはCと結合して微細析出する事により、内部の硬度を向上させ、静捩り破壊強度および捩り疲労強度の向上に寄与する。その効果が得られるのはNb:0.01%以上、V:0.0005%以上で、一方、Nb:0.10%超え、V:0.4%超えではその効果が飽和するため、上記範囲とする。
One or more of Nb: 0.01 to 0.10%, V: 0.0005 to 0.4% Nb and V combine with C to precipitate finely, thereby improving internal hardness and static torsion fracture Contributes to improvement of strength and torsional fatigue strength. The effect can be obtained when Nb: 0.01% or more, V: 0.0005% or more, while Nb: more than 0.10% and V: more than 0.4%, the effect is saturated. Range.

0.80≦C+Si/7+Mn/5+Cr/9+Mo/2+V/2≦1.00 ・・・(1)
1.11≦0.36×C+0.18×Si+0.27×Mn+0.30×Cr+0.43×Mo+135×B+0.24≦1.31 ・・・(2)
これらの式において各元素は含有量(質量%)を示し、含有しない元素は0とする。
0.80 ≦ C + Si / 7 + Mn / 5 + Cr / 9 + Mo / 2 + V / 2 ≦ 1.00 (1)
1.11 ≦ 0.36 × C + 0.18 × Si + 0.27 × Mn + 0.30 × Cr + 0.43 × Mo + 135 × B + 0.24 ≦ 1.31 (2)
In these formulas, each element indicates a content (mass%), and an element not included is 0.

(1)式は内部硬度をコントロールするための成分設計指針を示す。内部硬度が低いと捩り疲労強度が低下しやすく、高いと加工性が悪くなる。強度と加工性のバランスを考慮した上で最も良好な特性の得るため、(1)式の値を0.801.00とする。 Equation (1) indicates a component design guideline for controlling the internal hardness. If the internal hardness is low, the torsional fatigue strength tends to decrease, and if it is high, the workability deteriorates. In order to obtain the best characteristics in consideration of the balance between strength and workability, the value of equation (1) is set to 0.80 to 1.00 .

(2)式は30KHz以下の周波数を用いる一般的な高周波焼入れ条件において、有効硬化層深さの指標となる式で、捩り疲労強度の向上に、最適な有効硬化層深さ/半径とするため、(2)式の値を1.111.31とする。尚、本発明鋼の被削性を向上させるため、Pb、Ca等の快削元素を含有させてもよい。 Equation (2) is an equation that is an index of effective hardened layer depth under general induction hardening conditions using a frequency of 30 KHz or less, and is used to obtain an optimum effective hardened layer depth / radius for improving torsional fatigue strength. , (2) values are set to 1.11 to 1.31 . In order to improve the machinability of the steel of the present invention, free cutting elements such as Pb and Ca may be included.

[前組織]
本発明鋼は熱間圧延後、高周波焼入れ前のミクロ組織を初析フェライト体積率が15%未満のパーライト主体の組織とする。フェライト分率が15%以上となると、焼入れ深さのバラツキが大きくなるばかりでなく、高周波焼入れ・焼戻し後の表面硬さが低下して部品としての強度を確保できない。
[Previous organization]
In the steel of the present invention, the microstructure before hot quenching and before induction hardening is made to be a pearlite-based structure having a proeutectoid ferrite volume fraction of less than 15%. When the ferrite fraction is 15% or more, not only the variation in the quenching depth increases, but also the surface hardness after induction hardening and tempering decreases, and the strength as a part cannot be secured.

本発明に係る高周波焼入れ用鋼を素材として、高周波焼入れ部品を製造する場合、一般的な高周波焼入れに用いられる、30KHz以下の周波数で焼入れして、1.有効硬化層深さ/半径の比を0.4〜0.6、2.焼入れ部の結晶粒度:粒度7.0以上とし、特に静捩り破壊強度を向上させる場合、後述するパラメータ式((3)式)を満足させるように、硬度分布と軸寸法(軸径)の関係を調整する。尚、本発明鋼は軸状の形状を有する部品の素材として好適であるが、限定するものではない。軸状の形状を有する部品でない場合は、以下の説明において、半径を板厚方向の深さとする。但し、(3)式は軸状部材を対象とする場合にのみ適用する。   When producing induction-hardened parts using the induction-quenched steel according to the present invention as a raw material, the steel is quenched at a frequency of 30 KHz or less, which is used for general induction hardening. 1. Effective hardened layer depth / radius ratio of 0.4 to 0.6; Hardened part crystal grain size: When the grain size is 7.0 or more, especially when improving the static torsional fracture strength, the relationship between the hardness distribution and the shaft dimension (shaft diameter) so as to satisfy the parameter formula (formula (3)) described later Adjust. In addition, although this invention steel is suitable as a raw material of the components which have an axial shape, it is not limited. When the part is not a part having an axial shape, the radius is defined as the depth in the thickness direction in the following description. However, the formula (3) is applied only when the shaft-shaped member is targeted.

捩り疲労強度は硬化層深さによって変わり、硬化層深さ/半径の値が0.4未満では、硬化層が薄くて、疲労亀裂が発生しやすく、一方、硬化層深さ/半径の値が0.6を超えると、部品内部から疲労亀裂が発生しやすくなるため、0.4〜0.6とする。   The torsional fatigue strength varies depending on the hardened layer depth. When the hardened layer depth / radius value is less than 0.4, the hardened layer is thin and fatigue cracks are likely to occur. If it exceeds 0.6, fatigue cracks are likely to occur from the inside of the part, so 0.4 to 0.6.

焼入れ部の結晶粒度が粒度7.0未満の場合、鋼中不純物による粒界の脆化が起こりやすくなり、粒界を起点とした疲労亀裂が発生しやすくなるため、焼入れ部の結晶粒度は粒度7.0以上とする。   When the grain size of the quenched part is less than 7.0, the grain boundary becomes brittle due to impurities in the steel, and fatigue cracks starting from the grain boundary are likely to occur. 7.0 or higher.

静捩り破壊強度を向上させる場合、表層から中心までの硬度分布プロファイルを最適化することが有効で、(3)式を満足するように高周波焼入れ条件を制御する。また、部品での捩り疲労強度をさらに向上させたい場合は高周波焼入れ・焼戻しを行った部分にショットピーニングを行ってもよい。以下、本発明を実施例により比較例と対比し、その作用効果を詳細に説明する。   In order to improve the static torsional fracture strength, it is effective to optimize the hardness distribution profile from the surface layer to the center, and the induction hardening conditions are controlled so as to satisfy the expression (3). Further, when it is desired to further improve the torsional fatigue strength of the part, shot peening may be performed on the portion subjected to induction hardening and tempering. Hereinafter, the present invention will be compared with comparative examples by way of examples, and the effects thereof will be described in detail.

表1に示す化学成分を有する鋼を常法により溶解ー溶製ー熱間圧延し、直径40mmの丸棒鋼を調製した。表中、No.1〜31は、本発明範囲内の成分組成を有する開発鋼で、No.32〜46は本発明範囲外の成分組成を有する比較例である。No.47は従来鋼でJIS S45Cで、本発明範囲外の成分組成である。   Steel having the chemical components shown in Table 1 was melted, melted, and hot-rolled by a conventional method to prepare a round steel bar having a diameter of 40 mm. In the table, No. 1-31 are developed steels having a component composition within the scope of the present invention. 32 to 46 are comparative examples having component compositions outside the scope of the present invention. No. 47 is a conventional steel and is JIS S45C, which is a component composition outside the scope of the present invention.

得られた丸棒鋼を800mm長さに切断加工し、両端部それぞれ100mm長さ位置までを鍛造して60φとした後、さらに機械加工により、平行部が圧延ままのサイズである40mmφで300mm長さの丸棒試験片とし、高周波焼入れ・焼戻し処理を施し、静捩り破壊試験用および捩り疲労試験用試験片とした。図1に静捩り破壊試験用および捩り疲労試験用試験片の形状を示す。   The obtained round steel bar was cut into a length of 800 mm, both ends were forged up to 100 mm length positions to 60φ, and further machined to a parallel portion of 40 mmφ and a length of 300 mm at 40 mmφ. A round bar test piece was subjected to induction hardening and tempering treatment to obtain a test piece for static torsional fracture test and torsional fatigue test. FIG. 1 shows the shapes of test pieces for a static torsional fracture test and a torsional fatigue test.

高周波焼入れ・焼戻しは、全ての供試鋼で、周波数5KHz、移動速度9mm/秒で高周波焼入れを行い、その後160℃で2時間の焼戻しを行った。尚、用いた条件は、従来より、S45Cを素材とする部品で同じ軸径の部品で採用されている条件である。   Induction hardening and tempering were performed on all test steels by induction hardening at a frequency of 5 KHz and a moving speed of 9 mm / second, and then tempering at 160 ° C. for 2 hours. The conditions used are those conventionally used for parts made of S45C and having the same shaft diameter.

尚、開発鋼No.32の鋼材については、上記高周波焼入れ条件で作成した試験片(No.32−1)に加えて、高周波焼入れ条件を変えた捩り試験片も作成した。   The developed steel No. For the steel material No. 32, in addition to the test piece (No. 32-1) prepared under the induction hardening conditions, a torsion test piece with different induction hardening conditions was also prepared.

試験片No.31−2、31−3、31−4は、それぞれ周波数10KHz、30KHz、32KHzとし、送り速度を調整して、前記高周波焼入れ条件で作成したものと同等の硬度分布とした。   Specimen No. 31-2, 31-3, and 31-4 had frequencies of 10 KHz, 30 KHz, and 32 KHz, respectively, and the feed rate was adjusted to have a hardness distribution equivalent to that produced under the induction hardening conditions.

試験片No.31−5は、周波数は5KHzのままで送り速度を12mm/秒と速めて硬化層深さ/半径の比を本発明範囲よりも小さくした。
試験片No.31−6は、周波数は5KHzのままで送り速度を6mm/秒と遅くして硬化層深さ/半径の比を本発明よりも大きくした。
Specimen No. In the case of 31-5, the ratio of the hardened layer depth / radius was made smaller than the range of the present invention by increasing the feed rate to 12 mm / second while maintaining the frequency at 5 KHz.
Specimen No. In the case of 31-6, the ratio of the hardened layer depth / radius was made larger than that of the present invention by reducing the feed rate to 6 mm / second while keeping the frequency at 5 KHz.

試験片No.32−2は、周波数32KHz、送り7mm/秒で焼入加熱時の最高到達温度を上げて、前記高周波焼入れ条件で作成したものと同等の硬度分布を保ちながら、結晶粒を大きくした。   Specimen No. No. 32-2 increased the maximum temperature during quenching heating at a frequency of 32 KHz and a feed rate of 7 mm / second, and increased the crystal grains while maintaining the same hardness distribution as that prepared under the induction hardening conditions.

試験片No.32−3は、周波数は5KHzのままで送り速度を12mm/秒と速めて硬化層深さ/半径の比を本発明範囲よりも小さくした。   Specimen No. In No. 32-3, the feed rate was increased to 12 mm / sec with the frequency kept at 5 KHz, and the ratio of the cured layer depth / radius was made smaller than the range of the present invention.

試験片No.32−4は、周波数は5KHzのままで送り速度を6mm/秒と遅くして硬化層深さ/半径の比を本発明よりも大きくした。   Specimen No. In the case of 32-4, the ratio of the hardened layer depth / radius was made larger than that of the present invention by reducing the feed rate to 6 mm / second while keeping the frequency at 5 KHz.

高周波焼入れ、焼戻しを行った後、焼入れ層の結晶粒度を測定した。さらに、高周波焼入れされた軸部を切断し、ビッカース硬度試験機を用いて表面硬度、内部硬度、および断面の硬度分布を中心まで測定した。   After induction hardening and tempering, the crystal grain size of the quenched layer was measured. Further, the induction-quenched shaft portion was cut, and the surface hardness, internal hardness, and cross-sectional hardness distribution were measured to the center using a Vickers hardness tester.

有効硬化層深さはビッカース硬さで450HVの得られる深さを、断面の円周形状の表面で45°づつ位置を変えて8方向において調査した結果の平均を求めて、有効硬化層深さとした。硬化層深さムラは8方向のそれぞれにおいて求められる有効硬化層深さを比較して、最大値と最小値の差が0.2mm以上の場合を硬化層深さムラ有りとした。また、硬度分布の測定結果を用いて(3)式を計算した。   The effective hardened layer depth is obtained by calculating the average of the results obtained by examining the depth obtained at 450 HV in Vickers hardness and changing the position by 45 ° on the circumferential surface of the cross section in 8 directions. did. The cured layer depth unevenness was compared with the effective cured layer depth required in each of the eight directions, and when the difference between the maximum value and the minimum value was 0.2 mm or more, the cured layer depth unevenness was determined. Moreover, (3) Formula was calculated using the measurement result of hardness distribution.

静捩り破壊試験は試験片の両端部(鍛造ままで60Φ)の一方の片端部を固定し、他方のつかみ部を1°/分で回転させて破断させて、最大トルクを求めて評価した。   In the static torsion fracture test, one end of one end of the test piece (60Φ as it was forged) was fixed, and the other grip was rotated at 1 ° / min to break, and the maximum torque was determined and evaluated.

捩り疲労試験は、試験片を固定し、両端部を反対方向に同一変位だけ捩ってトルクを加えて行い、1千万回の繰り返しの捩りでも破断しない最大トルクを疲労強度として評価した。   The torsional fatigue test was performed by fixing the test piece, twisting both ends in the opposite direction by the same displacement and applying torque, and evaluating the maximum torque that does not break even after repeated 10 million torsion as the fatigue strength.

表2に高周波焼入れ・焼戻し後の試験片性状および静捩り破壊試験、捩り疲労試験の結果を示す。尚、供試鋼の高周波焼入れ前の組織は、いずれの供試鋼でも本発明の規定を満足していた。   Table 2 shows the properties of the test pieces after induction hardening and tempering and the results of static torsional fracture test and torsional fatigue test. Note that the structure of the test steel before induction hardening satisfied the provisions of the present invention for any of the test steels.

No.1〜31−3の試験片は目標とする有効硬化層深さが得られ、高い静捩り破壊強度ならびに捩り疲労強度が得られていることが確認された。   No. It was confirmed that the target effective hardened layer depth was obtained for the test pieces 1 to 31-3, and high static torsional fracture strength and torsional fatigue strength were obtained.

特に、(1)式および(2)式を満足したNo.1、2、4、7、10〜13、15〜18、23〜31−3の試験片はより高い捩り疲労強度が得られており、(3)式を満足したNo.1〜3、5、6、8、10〜18、20〜31−3の試験片はより高い静捩り破壊強度が得られていた。   In particular, No. 1 satisfying the expressions (1) and (2). The test pieces of 1, 2, 4, 7, 10-13, 15-18, 23-31-3 had higher torsional fatigue strength, and No. 1 satisfying the expression (3) was obtained. The test pieces of 1 to 3, 5, 6, 8, 10 to 18, and 20 to 31-3 had higher static torsional fracture strength.

(1)、(2)、(3)式のすべてを満足したNo.1、2、10〜13、15〜18、23〜31−3の試験片は静捩り破壊強度および捩り疲労強度ともに、その他の試験片と比較してより高い値が得られた。   No. 1 satisfying all of the expressions (1), (2) and (3). The test pieces of 1, 2, 10-13, 15-18 and 23-31-3 were higher in both static torsion fracture strength and torsional fatigue strength than the other test pieces.

それに対し、比較例となる試験片No.32はC含有量が本発明範囲より低く、硬化層深さにムラが認められ、表面硬度も低い値だった。さらに硬化層深さも浅くなっていた。そのため、静捩り破壊強度が低く、捩り疲労強度も低い結果であった。   On the other hand, the test piece No. No. 32 had a C content lower than the range of the present invention, unevenness in the cured layer depth was observed, and the surface hardness was also low. Furthermore, the depth of the hardened layer was also shallow. Therefore, the static torsional fracture strength was low and the torsional fatigue strength was also low.

試験片No.33はC含有量が本発明の範囲を超えて多いため、焼入性が高すぎて焼き割れが発生し、静捩り破壊強度および捩り疲労強度は調査不可能であった。
試験片No.34はSi含有量が本発明の範囲よりも低いため製鋼での製造時に生成した酸化物が多く残って疲労起点となって、捩り疲労強度が低下した。
Specimen No. No. 33 has a C content exceeding the range of the present invention, so that the hardenability is too high and a crack is generated, and the static torsional fracture strength and torsional fatigue strength cannot be investigated.
Specimen No. In No. 34, since the Si content was lower than the range of the present invention, a large amount of oxide generated during production in steelmaking remained and became a fatigue starting point, and the torsional fatigue strength was lowered.

試験片No.35はSi含有量が本発明の範囲を超えて高く、内部硬さが高くなりすぎ、静捩り破壊強度が低下した。試験片No.36はMn含有量が本発明の範囲より低く、焼入性が低く、有効硬化層深さが浅くなりすぎて、静捩り破壊強度、および捩り疲労疲労強度ともに低下した。   Specimen No. No. 35 had a high Si content exceeding the range of the present invention, the internal hardness became too high, and the static torsional fracture strength decreased. Specimen No. In No. 36, the Mn content was lower than the range of the present invention, the hardenability was low, the effective hardened layer depth was too shallow, and both the static torsional fracture strength and the torsional fatigue fatigue strength were reduced.

試験片No.37はMn含有量が本発明範囲より高いために焼入性が高くて焼き割れが発生した。試験片No.38はP含有量が本発明の範囲より高くなったために粒界が脆くなり、静捩り破壊強度および捩り疲労強度がともに低下した。   Specimen No. No. 37 had a high Mn content and therefore had high hardenability and caused cracking. Specimen No. In No. 38, since the P content was higher than the range of the present invention, the grain boundary became brittle, and both the static torsional fracture strength and the torsional fatigue strength decreased.

試験片No.39はS含有量が本発明の範囲より高く、そのためにMnS介在物が多くなりすぎて、焼入性を低下させ、静捩り破壊強度が低下した。また、多量のMnSが存在したため捩り疲労強度の破壊起点となって捩り疲労強度が低下した。   Specimen No. No. 39 had an S content higher than the range of the present invention, so that MnS inclusions were excessive, thereby reducing the hardenability and reducing the static torsional fracture strength. In addition, since a large amount of MnS was present, the torsional fatigue strength decreased as a starting point of torsional fatigue strength.

試験片No.40はCr含有量が本発明範囲よりも低く、そのために焼入性が低下して内部硬さが低く、有効硬化層深さが浅いために静捩り破壊強度および捩り疲労強度が低下した。   Specimen No. In No. 40, the Cr content was lower than the range of the present invention, so that the hardenability was lowered, the internal hardness was low, and the effective hardened layer depth was shallow, so that the static torsional fracture strength and torsional fatigue strength were reduced.

試験片No41はCr含有量が本発明範囲よりも高いために焼入性が高く、焼き割れが発生した。試験片No.42はMo含有量が本発明の範囲より高く、その結果、硬化層深さが深くなりすぎて、捩り疲労強度が低下した。   Since test piece No41 had Cr content higher than the range of this invention, its hardenability was high and the burning crack generate | occur | produced. Specimen No. No. 42 had a Mo content higher than the range of the present invention. As a result, the depth of the hardened layer became too deep, and the torsional fatigue strength was lowered.

試験片No.43はB含有量が本発明の範囲より低く、焼入性が低下したために硬化層深さが浅くなり、静捩り破壊強度および捩り疲労強度が低下した。   Specimen No. In No. 43, the B content was lower than the range of the present invention, and the hardenability decreased, so that the hardened layer depth became shallow, and the static torsional fracture strength and torsional fatigue strength decreased.

試験片No.44はTi含有量が本発明の範囲より低く、固溶したBが確保できずに焼入性が低下した。そのため硬化層深さが浅くなり、静捩り破壊強度および捩り疲労強度が低下した。   Specimen No. No. 44 had a Ti content lower than the range of the present invention, and solid solution B could not be secured, resulting in a decrease in hardenability. Therefore, the hardened layer depth became shallow, and static torsional fracture strength and torsional fatigue strength decreased.

試験片No.45はTi含有量が本発明の範囲より高いため、TiN介在物が多くて破壊起点となり、静捩り破壊強度および捩り疲労強度が低下した。   Specimen No. No. 45 has a Ti content higher than the range of the present invention, so that there were many TiN inclusions and became the starting point of fracture, and static torsional fracture strength and torsional fatigue strength were reduced.

試験片No.46はN含有量が本発明の範囲より高く、固溶したBが確保できずに焼入性が低下して硬化層深さが浅くなって、静捩り破壊強度および捩り疲労強度が低下した。   Specimen No. No. 46 had a higher N content than the range of the present invention, and could not secure solid solution B, but the hardenability decreased and the hardened layer depth became shallow, and the static torsional fracture strength and torsional fatigue strength decreased.

従来鋼No.47はBが添加されていないために焼入性が低く、硬化層深さが浅くて、また結晶粒も大きかった。そのため静捩り破壊強度および捩り疲労強度が低下した。   Conventional steel No. 47 had no hardenability because B was not added, the hardened layer was shallow, and the crystal grains were large. As a result, static torsional fracture strength and torsional fatigue strength decreased.

また、開発鋼である試験片No.31を従来よりも高い周波数で高周波焼入れしたNo.31−4は結晶粒度が発明範囲よりも小さく、結晶粒が大きいために捩り疲労強度が低下した。硬化層深さを発明範囲より浅くしたNo.31−5および、発明範囲よりも硬化層深さを深くしたNo.31−6は静捩り破壊強度および捩り疲労強度が低下した。   In addition, test piece No. No. 31 was induction hardened at a higher frequency than before. In 31-4, the crystal grain size was smaller than the range of the invention, and the torsional fatigue strength decreased because the crystal grains were large. No. with a hardened layer depth shallower than the scope of the invention. 31-5 and No. 31 in which the depth of the hardened layer was deeper than the scope of the invention. In 31-6, the static torsional fracture strength and torsional fatigue strength were reduced.

Claims (5)

質量%で、C:0.40〜0.55%、Si:0.15〜0.50%、Mn:0.60〜2.00%、P:0.030%以下、S:0.005〜0.060%、Cr:0.05〜0.50%、Mo:0.35%以下、B:0.0005〜0.0080%、Ti:0.010〜0.035%、N≦0.0100%を含有し、残部Feおよび不可避的不純物からなる成分組成と、初析フェライト体積率が15%未満のパーライト主体のミクロ組織を備え、
前記成分組成が、更に、下記(1)および(2)式を満足する事を特徴とする高周波焼入れ用鋼。
0.80≦C+Si/7+Mn/5+Cr/9+Mo/2+V/2≦1.00 ・・・(
1)
1.11≦0.36×C+0.18×Si+0.27×Mn+0.30×Cr+0.43
×Mo+135×B+0.24≦1.31 ・・・(2)
これらの式において各元素は含有量(質量%)を示し、含有しない元素は0とする。
In mass%, C: 0.40 to 0.55%, Si: 0.15 to 0.50%, Mn: 0.60 to 2.00%, P: 0.030% or less, S: 0.005 -0.060%, Cr: 0.05-0.50%, Mo: 0.35% or less, B: 0.0005-0.0080%, Ti: 0.010-0.035%, N≤0 0.0100%, a composition comprising the balance Fe and inevitable impurities, and a pearlite-based microstructure with a proeutectoid ferrite volume fraction of less than 15%,
The steel for induction hardening , wherein the component composition further satisfies the following formulas (1) and (2) .
0.80 ≦ C + Si / 7 + Mn / 5 + Cr / 9 + Mo / 2 + V / 2 ≦ 1.00 (
1)
1.11 ≦ 0.36 × C + 0.18 × Si + 0.27 × Mn + 0.30 × Cr + 0.43
× Mo + 135 × B + 0.24 ≦ 1.31 (2)
In these formulas, each element indicates a content (mass%), and an element not included is 0.
成分組成に、更に、質量%で、V:0.005〜0.4%、Nb:0.01〜0.10%の1種以上を含むことを特徴とする請求項1記載の高周波焼入れ用鋼。   The component composition further comprises one or more of V: 0.005 to 0.4% and Nb: 0.01 to 0.10% by mass%, according to claim 1, steel. 請求項1又は2に記載の高周波焼入れ用鋼を素材とし、圧延、鍛造若しくは機械加工またはそれらの組み合わせにより軸部を有する部品形状とした後、前記軸部を高周波焼入れ・焼戻しにより有効硬化層深さ/半径の比が0.4〜0.6、焼入れ部の結晶粒度は粒度7.0以上とした、静捩り破壊強度および捩り疲労強度に優れた高周波焼入れ部品。 The steel for induction hardening according to claim 1 or 2 is used as a raw material, and after forming into a part shape having a shaft portion by rolling, forging or machining or a combination thereof, the effective hardening layer depth is obtained by induction hardening and tempering. Induction-hardened parts having excellent static torsional fracture strength and torsional fatigue strength with a thickness / radius ratio of 0.4 to 0.6 and a grain size of the quenched portion of 7.0 or more. 更に、高周波焼入れ・焼戻しをした後の硬さ分布が、下記(3)式を満足することを特徴とする請求項に記載の静捩り破壊強度および捩り疲労強度に優れた高周波焼入れ部品。

Furthermore, the hardness distribution after induction hardening and tempering satisfies the following formula (3): The induction hardening component excellent in static torsional fracture strength and torsional fatigue strength according to claim 3 .

高周波焼入れ・焼戻しを施した部分に、更に、ショットピーニングを行うことを特徴とする、請求項4に記載の静捩り破壊強度および捩り疲労強度に優れた高周波焼入れ部品。The induction-quenched part excellent in static torsional fracture strength and torsional fatigue strength according to claim 4, wherein shot peening is further performed on the portion subjected to induction hardening and tempering.
JP2009035005A 2009-02-18 2009-02-18 Induction hardening steel and induction hardening parts with excellent static torsional fracture strength and torsional fatigue strength Active JP5583352B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2009035005A JP5583352B2 (en) 2009-02-18 2009-02-18 Induction hardening steel and induction hardening parts with excellent static torsional fracture strength and torsional fatigue strength

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2009035005A JP5583352B2 (en) 2009-02-18 2009-02-18 Induction hardening steel and induction hardening parts with excellent static torsional fracture strength and torsional fatigue strength

Publications (2)

Publication Number Publication Date
JP2010189702A JP2010189702A (en) 2010-09-02
JP5583352B2 true JP5583352B2 (en) 2014-09-03

Family

ID=42816047

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2009035005A Active JP5583352B2 (en) 2009-02-18 2009-02-18 Induction hardening steel and induction hardening parts with excellent static torsional fracture strength and torsional fatigue strength

Country Status (1)

Country Link
JP (1) JP5583352B2 (en)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5445345B2 (en) * 2010-06-17 2014-03-19 新日鐵住金株式会社 Steel bar for steering rack bar and manufacturing method thereof
US9533531B2 (en) * 2012-11-20 2017-01-03 Mitchell Z. Dziekonski Modular axle shaft assemblies for use with racing vehicles and other vehicles
JP7009938B2 (en) * 2017-11-07 2022-01-26 日産自動車株式会社 Axle shaft
CN109402517A (en) * 2018-12-28 2019-03-01 首钢集团有限公司 One kind exempting from cold forging pinion steel and preparation method thereof of annealing

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3809004B2 (en) * 1998-02-24 2006-08-16 新日本製鐵株式会社 Induction quenching steel with excellent high strength and low heat treatment strain characteristics and its manufacturing method

Also Published As

Publication number Publication date
JP2010189702A (en) 2010-09-02

Similar Documents

Publication Publication Date Title
US20130186522A1 (en) Carburizing steel having excellent cold forgeability and method of manufacturing the same
KR20090125134A (en) Case-hardened steel pipe excellent in workability and process for production thereof
JP4581966B2 (en) Induction hardening steel
JP2007146232A (en) Method for producing soft-nitrided machine part made of steel
WO2019244503A1 (en) Mechanical component
JP2004225102A (en) High strength steel for pinion shaft, and production method therefor
JPH10195589A (en) Induction hardened steel material with high torsional fatigue strength
JP5583352B2 (en) Induction hardening steel and induction hardening parts with excellent static torsional fracture strength and torsional fatigue strength
JPH11236644A (en) Steel for induction hardening excellent in high strength characteristic and low heat treating strain characteristic and its production
JP6057626B2 (en) Machine structural steel with low heat treatment deformation
JPH08283910A (en) Steel material for induction hardened shaft parts, combining cold workability with torsional fatigue strength characteristic
JP2004027334A (en) Steel for induction tempering and method of producing the same
JP3842888B2 (en) Method of manufacturing steel for induction hardening that combines cold workability and high strength properties
JP4448047B2 (en) A steel for skin hardening that has excellent grain coarsening resistance and cold workability, and can omit softening annealing.
JP4488228B2 (en) Induction hardening steel
JP2012237052A (en) Case-hardened steel excellent in cold forgeability and suppressing ability of crystal grain coarsening, and method for manufacturing the same
JP4752800B2 (en) Non-tempered steel
JP4556770B2 (en) Carburizing steel and method for producing the same
JP4757831B2 (en) Induction hardening part and manufacturing method thereof
JPH09111401A (en) Steel for machine structural use, excellent in machinability and quenching crack resistance, and its production
JP2004183065A (en) High strength steel for induction hardening, and production method therefor
JP2006265703A (en) Steel for case hardening having excellent crystal grain coarsening resistance and cold workability and method for producing the same
JP2007231411A (en) Method of manufacturing machine structure component
JP2004124190A (en) Induction-tempered steel having excellent twisting property
JP6394844B1 (en) Shaft member

Legal Events

Date Code Title Description
A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20110906

RD03 Notification of appointment of power of attorney

Free format text: JAPANESE INTERMEDIATE CODE: A7423

Effective date: 20120322

RD04 Notification of resignation of power of attorney

Free format text: JAPANESE INTERMEDIATE CODE: A7424

Effective date: 20120328

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20130820

A521 Written amendment

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20131015

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20131210

A521 Written amendment

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20140207

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20140408

A521 Written amendment

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20140606

TRDD Decision of grant or rejection written
A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

Effective date: 20140624

A61 First payment of annual fees (during grant procedure)

Free format text: JAPANESE INTERMEDIATE CODE: A61

Effective date: 20140716

R150 Certificate of patent or registration of utility model

Ref document number: 5583352

Country of ref document: JP

Free format text: JAPANESE INTERMEDIATE CODE: R150

S111 Request for change of ownership or part of ownership

Free format text: JAPANESE INTERMEDIATE CODE: R313114

R360 Written notification for declining of transfer of rights

Free format text: JAPANESE INTERMEDIATE CODE: R360

R360 Written notification for declining of transfer of rights

Free format text: JAPANESE INTERMEDIATE CODE: R360

R371 Transfer withdrawn

Free format text: JAPANESE INTERMEDIATE CODE: R371

S111 Request for change of ownership or part of ownership

Free format text: JAPANESE INTERMEDIATE CODE: R313114

R350 Written notification of registration of transfer

Free format text: JAPANESE INTERMEDIATE CODE: R350

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250