JP4728884B2 - Induction contour hardened steel and induction contour hardened parts with excellent low cycle fatigue characteristics - Google Patents

Induction contour hardened steel and induction contour hardened parts with excellent low cycle fatigue characteristics Download PDF

Info

Publication number
JP4728884B2
JP4728884B2 JP2006167569A JP2006167569A JP4728884B2 JP 4728884 B2 JP4728884 B2 JP 4728884B2 JP 2006167569 A JP2006167569 A JP 2006167569A JP 2006167569 A JP2006167569 A JP 2006167569A JP 4728884 B2 JP4728884 B2 JP 4728884B2
Authority
JP
Japan
Prior art keywords
less
steel
induction
core
hardened
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
JP2006167569A
Other languages
Japanese (ja)
Other versions
JP2007332439A (en
Inventor
達朗 越智
Original Assignee
新日本製鐵株式会社
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 新日本製鐵株式会社 filed Critical 新日本製鐵株式会社
Priority to JP2006167569A priority Critical patent/JP4728884B2/en
Publication of JP2007332439A publication Critical patent/JP2007332439A/en
Application granted granted Critical
Publication of JP4728884B2 publication Critical patent/JP4728884B2/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Description

本発明は、表層部に高周波焼入れ処理が行われる部品に用いられる低サイクル疲労特性に優れた高周波輪郭焼入れ鋼材、及び高周波輪郭焼入れ部品に関する。   The present invention relates to a high-frequency contour-quenched steel material excellent in low-cycle fatigue characteristics and a high-frequency contour-quenched component, which are used for components subjected to induction hardening on the surface layer portion.
歯車、軸受部品、転動部品、シャフト、及び等速ジョイント部品を高周波輪郭焼入れ処理によって形成する場合、通常、例えばJIS G 4052、JIS G 4104〜4106等に規定されている中炭素の機械構造用合金鋼を、冷間鍛造(転造を含む)又は熱間鍛造−切削により所定の形状に加工した後、輪郭部分に高周波焼入れ(例えば焼入れ深さが0.5〜3mm)を行うことにより形成されている。上記した歯車及び部品は、大きな衝撃が繰り返し加わることにより、繰り返し回数が少ないにもかかわらず疲労破壊することがある。このため、このような疲労破壊に対する耐性(以下、低サイクル疲労特性と記載)が求められている。   When forming gears, bearing parts, rolling parts, shafts, and constant velocity joint parts by high-frequency contour quenching, it is usually used for medium-carbon machine structures defined in JIS G 4052, JIS G 4104-4106, etc. After alloy steel is processed into a predetermined shape by cold forging (including rolling) or hot forging-cutting, it is formed by induction hardening (for example, the quenching depth is 0.5 to 3 mm) in the contour portion. Has been. The gears and parts described above may undergo fatigue failure due to repeated large impacts despite a small number of repetitions. For this reason, resistance to such fatigue fracture (hereinafter referred to as low cycle fatigue characteristics) is required.
低サイクル疲労特性を改善する為の技術としては、例えば浸炭鋼材における技術であるが、特許文献1に記載の技術及び特許文献2に記載の技術がある。
特許文献1に記載の技術は、塑性変形抵抗及び粒界強度の和を一定値以上にすることにより、低サイクル疲労特性を改善するものである。塑性変形抵抗は、鋼材の化学的成分を変数とした式によって算出されるものであり、実質的には芯部硬さが高いほど高くなる。また粒界強度が高い場合は靭性が高くなる。なお、切削性を維持するために、塑性変形抵抗及び粒界強度の和には上限が設けられている。
As a technique for improving the low cycle fatigue characteristics, for example, a technique in carburized steel, there is a technique described in Patent Document 1 and a technique described in Patent Document 2.
The technique described in Patent Document 1 improves low cycle fatigue characteristics by setting the sum of plastic deformation resistance and grain boundary strength to a certain value or more. The plastic deformation resistance is calculated by an equation using the chemical component of the steel as a variable, and substantially increases as the core hardness increases. Further, when the grain boundary strength is high, the toughness becomes high. In order to maintain the machinability, an upper limit is set for the sum of the plastic deformation resistance and the grain boundary strength.
特許文献2に記載の技術は、芯部硬さ及び浸炭層の靭性それぞれを基準値以上にすることにより、低サイクル疲労特性を改善するものである。なお、芯部硬さ及び浸炭層の靭性それぞれは、鋼材の化学的成分を変数とした関数により整理されている。
特開平10−259450号公報(第13及び14段落、図1) 特開2004−238702号公報(第25及び26段落)
The technique described in Patent Document 2 improves the low cycle fatigue characteristics by setting the core hardness and the toughness of the carburized layer to be equal to or higher than a reference value. Each of the core hardness and the toughness of the carburized layer is organized by a function with the chemical component of the steel material as a variable.
JP-A-10-259450 (13th and 14th paragraphs, FIG. 1) JP 2004-238702 A (25th and 26th paragraphs)
上記した従来の技術によれば、硬化層の靭性及び芯部硬さそれぞれが高いほど低サイクル疲労特性が向上する。しかし、本発明者が検討した結果、芯部硬さを高くしても、必ずしも低サイクル疲労特性が十分な値を示すとは限らないことが判明した。
本発明は上記のような事情を考慮してなされたものであり、その目的は、低サイクル疲労特性を安定して良くすることができる、低サイクル疲労特性に優れた高周波輪郭焼入れ鋼材及び高周波輪郭焼入れ部品を提供することにある。
According to the above-described conventional technique, the higher the toughness and core hardness of the hardened layer, the lower the low cycle fatigue characteristics. However, as a result of studies by the present inventors, it has been found that even if the core hardness is increased, the low cycle fatigue characteristics do not always exhibit a sufficient value.
The present invention has been made in consideration of the above-described circumstances, and the object thereof is to stabilize and improve the low cycle fatigue characteristics, and the high frequency contour quenched steel material and the high frequency contour excellent in the low cycle fatigue characteristics. It is to provide a hardened part.
上記課題を解決するための本発明の要旨は以下の通りである。
(a) 質量%で、
C:0.35〜0.6%、
Si:0.01〜1.0%、
Mn:0.2〜1.8%、
S:0.001〜0.15%、
Al:0.001〜0.05%、
N:0.002〜0.020%、
P:0.025%以下、
O:0.0025%以下
Cr:1.8%以下、
含有し、さらに、
o:1.5%以下、
Ni:3.5%以下、
B:0.006%以下、
V:0.5%以下、
Nb:0.04%以下、
Ti:0.2%以下、
の1種又は2種以上を含有し、残部が鉄及び不可避的不純物からなり、表層に高周波焼入れ処理を施した鋼材であって、
(ア)高周波焼入れによる有効硬化層深さが0.5〜3mmであり、
(イ)高周波焼入れ硬化層の旧オーステナイト結晶粒度Nγが8〜15番であり、
(ウ)芯部のフェライト分率が50%以下であり、
(エ)芯部組織において、パーライト、フェライト、及びベイナイトの有効結晶粒径が50μm以下であり、
(オ)下記(1)式で定義される投影芯部硬さHp-coreがHV370以上であり、
(カ)下記(2)式で定義されるA及び下記(3)式で定義されるBが、A−0.00000293×B≧−14の関係を有することを特徴とする、低サイクル疲労特性に優れた高周波輪郭焼入れ鋼材。
Hp-core=Hcore/(1−t/r) …(1)
ただし、Hcore;芯部硬さ、t;有効硬化層深さ、r;破損部位の半径または破損部位の肉厚の半分である。
A=Mo+0.227Ni+190B−7.18C−0.087Si−17.2P−2.74V−0.00955Hs+0.0344Nγ …(2)
ただし、Hs;表面硬さ(HV)、Nγ;高周波焼入れ硬化層の旧オーステナイト結晶粒度。
B=t×(Hcore) … (3)
The gist of the present invention for solving the above problems is as follows.
(A) In mass%,
C: 0.35-0.6%
Si: 0.01 to 1.0%,
Mn: 0.2-1.8%
S: 0.001 to 0.15%,
Al: 0.001 to 0.05%,
N: 0.002 to 0.020%,
P: 0.025% or less,
O: 0.0025% or less ,
Cr: 1.8% or less,
It contains, in addition,
M o: 1.5% or less,
Ni: 3.5% or less,
B: 0.006% or less,
V: 0.5% or less,
Nb: 0.04% or less,
Ti: 0.2% or less,
Is a steel material containing one or more of the following, the balance consisting of iron and inevitable impurities, and subjected to induction hardening treatment on the surface layer,
(A) the effective case depth by induction hardening are 0.5 to 3 mm,
(B) The prior austenite grain size Nγ of the induction-hardened hardened layer is No. 8-15,
(C) The ferrite fraction of the core is 50% or less,
(D) In the core structure, the effective crystal grain size of pearlite, ferrite, and bainite is 50 μm or less,
(E) below (1) Ri der projection core hardness Hp-core is HV370 or more defined by the equation,
(F) Low cycle fatigue characteristics, wherein A defined by the following formula (2) and B defined by the following formula (3) have a relationship of A−0.00000293 × B ≧ −14 High-frequency contour hardened steel.
Hp-core = Hcore / (1-t / r) (1)
Where Hcore: core hardness, t: effective hardened layer depth, r: half of the radius of the damaged part or the thickness of the damaged part.
A = Mo + 0.227Ni + 190B-7.18C-0.087Si-17.2P-2.74V-0.00955Hs + 0.0344Nγ (2)
Where Hs: surface hardness (HV), Nγ: prior austenite grain size of induction hardened layer.
B = t × (Hcore) 2 (3)
(b)表面の残留応力が−500MPa以下であることを特徴とする上記(a)に記載の低サイクル疲労特性に優れた高周波輪郭焼入れ鋼材。
(B) The high-frequency contour quenched steel material having excellent low cycle fatigue characteristics as described in (a) above, wherein the residual stress on the surface is −500 MPa or less.
(c)上記(a)または(b)に記載の高周波輪郭焼入れ鋼材を用いた高周波輪郭焼入れ部品。高周波輪郭焼入れ部品は例えば歯車である。
(C) A high-frequency contour-quenched part using the high-frequency contour-quenched steel described in (a) or (b ) above. The high-frequency contour quenched part is, for example, a gear.
本発明によれば、高周波輪郭焼入れ鋼材において低サイクル疲労特性を安定してよくすることができる。   According to the present invention, low cycle fatigue characteristics can be stably improved in a high-frequency contour hardened steel material.
本発明鋼は、歯車、軸受部品、転動部品、シャフト、及び等速ジョイント部品として使用される高周波輪郭焼入れ鋼材である。   The steel of the present invention is a high-frequency contour hardened steel material used as gears, bearing parts, rolling parts, shafts, and constant velocity joint parts.
本発明者は、鋭意検討の結果、高周波輪郭焼入れ鋼材の低サイクル疲労破壊は、次の過程により生じると考えた。
(A)高周波焼入れ硬化層と芯部の境界付近に歪みが集中し、微小亀裂が発生する。
(B)微小亀裂が高周波焼入れ硬化層に伝搬して、粒界割れを伴って高周波焼入れ硬化層が脆性破壊を起こす。
(C)その後、芯部が急速に破壊する。
As a result of intensive studies, the present inventor considered that low cycle fatigue failure of high-frequency contour-quenched steel is caused by the following process.
(A) Distortion concentrates near the boundary between the induction-hardened hardened layer and the core, and microcracks are generated.
(B) Microcracks propagate to the induction-hardened hardened layer, and the induction-hardened hardened layer causes brittle fracture with intergranular cracking.
(C) Thereafter, the core portion is rapidly broken.
まず、上記(A)の過程を抑制する手段を検討した。高周波焼入れ硬化層が顕著に浅い場合、又は芯部硬さが極度に低い場合、高周波焼入れ硬化層と芯部の境界付近への歪みの集中及び微小亀裂の発生は極めて容易に生じる。このため、高周波焼入れ硬化層深さ及び芯部硬さそれぞれを、ある臨界値以上にする必要がある。   First, means for suppressing the process (A) were studied. When the induction-hardened hardened layer is remarkably shallow, or when the core hardness is extremely low, the strain concentration near the boundary between the induction-hardened hardened layer and the core and the generation of microcracks occur very easily. For this reason, it is necessary to make each induction hardening hardened layer depth and core part hardness more than a certain critical value.
図1は、微小亀裂発生時の破壊メカニズムを説明する為の模式図である。芯部硬さを図中aからbに増加させた場合、破壊起点は変化しないが疲労強度は増加する。一方、有効硬化層深さを深くした場合、破壊起点はtからtに変化するため疲労強度は増加する。そこで、有効硬化層深さ及び芯部硬さの両者を同時に記述できる新しい指標として、下式(1)及び図1で定義される投影芯部硬さHp-coreを定義した。
Hp-core=Hcore/(1−t/r) …(1)
ただし、Hcore;芯部硬さ、t;有効硬化層深さ(JIS G 0559に規定)、r;破損部位の半径または破損部位の肉厚の半分である。破損部位とはいわゆる設計上の危険断面のことであり、歯車部品においては、図2に矢印で示した部分が破損部位の肉厚に相当する。シャフトのような軸状部品では、最小直径部や応力集中が最大となる断面の半径がこれに相当する。
FIG. 1 is a schematic diagram for explaining a fracture mechanism when a microcrack is generated. When the core hardness is increased from a to b in the figure, the fracture starting point does not change, but the fatigue strength increases. On the other hand, when the depth of the effective hardened layer depth, fracture origin fatigue strength to change from t 1 to t 2 is increased. Therefore, the projection core hardness Hp-core defined by the following formula (1) and FIG. 1 is defined as a new index that can describe both the effective hardened layer depth and the core hardness.
Hp-core = Hcore / (1-t / r) (1)
Hcore: core hardness, t: effective hardened layer depth (as defined in JIS G 0559), r: half of the radius of the damaged part or the thickness of the damaged part. The damaged part is a so-called design critical section, and in the gear part, the part indicated by the arrow in FIG. 2 corresponds to the thickness of the damaged part. In a shaft-like component such as a shaft, the minimum diameter portion and the radius of the cross section where the stress concentration is maximum correspond to this.
本発明者が検討した結果、後述する成分系においては、投影芯部硬さHp-coreがHV370未満であれば、低サイクル疲労時において高周波焼入れ硬化層と芯部の境界付近に微小亀裂が容易に発生するが、HV370以上であれば、この微小亀裂の発生を遅延できることが判明した。   As a result of the study by the present inventors, in the component system described later, if the projection core hardness Hp-core is less than HV370, microcracks are easily formed near the boundary between the induction-hardened hardened layer and the core during low cycle fatigue. However, it has been found that the generation of this microcrack can be delayed if it is HV370 or higher.
次に、上記(B)の過程を抑制する手段を検討した。高周波焼入れ硬化層と芯部の境界付近で発生した微小亀裂が高周波焼入れ硬化層に伝搬するか否かは、高周波焼入れ硬化層の靭性、及び微小亀裂先端の3軸応力度により決まると考えた。   Next, means for suppressing the process (B) were studied. It was considered that whether or not the microcrack generated near the boundary between the induction hardening layer and the core propagates to the induction hardening layer depends on the toughness of the induction hardening layer and the degree of triaxial stress at the tip of the microcrack.
高周波焼入れ硬化層の靭性は、表面硬さ(HV)、高周波焼入れ硬化層の旧オーステナイト結晶粒度及び芯部の化学的成分で決まるため、下記式(2)で定義される指標Aを導入した。指標Aが大きいほど高周波焼入れ硬化層の脆性破壊は抑制される。
A=Mo+0.227Ni+190B−7.18C−0.087Si−17.2P−2.74V−0.00955Hs+0.0344Nγ …(2)
ただし、Hs;表面硬さ(HV)、Nγ;高周波焼入れ硬化層の旧オーステナイト結晶粒度である。
Since the toughness of the induction-hardened hardened layer is determined by the surface hardness (HV), the prior austenite crystal grain size of the induction hardened hardened layer, and the chemical component of the core, the index A defined by the following formula (2) was introduced. As the index A is larger, brittle fracture of the induction-hardened hardened layer is suppressed.
A = Mo + 0.227Ni + 190B-7.18C-0.087Si-17.2P-2.74V-0.00955Hs + 0.0344Nγ (2)
Where Hs: surface hardness (HV), Nγ: old austenite grain size of induction hardened layer.
一方、微小亀裂先端の3軸応力度をあらわす指標として、有効硬化層深さ(t)及び芯部の硬さ(Hcore)の関数である下記式(3)で定義される指標Bを導入した。指標Bが小さいほど微小亀裂先端の3軸応力度は小さくなる。
B=t×(Hcore) … (3)
On the other hand, the index B defined by the following formula (3), which is a function of the effective hardened layer depth (t) and the core hardness (Hcore), was introduced as an index representing the degree of triaxial stress at the tip of the microcrack. . The smaller the index B, the smaller the triaxial stress level at the tip of the microcrack.
B = t × (Hcore) 2 (3)
図3は、低サイクル疲労強度の試験結果(本図においては負荷回数が5000回で破断する場合の曲げ応力)と指標Bの関係を示す。試験片は、平行部の直径が12mmの円柱形であり、中央に半円弧の切り欠きを有している。切り欠き半径R=1であり、切り欠き底直径は10mmである。試験方法は荷重制御4点曲げ疲労試験であり、最大負荷応力と最小負荷応力の応力比は0.1、周波数は5Hzである。
本図から、指標Bが小さいほど高周波焼入れ硬化層の脆性破壊が抑制されて低サイクル疲労強度は向上することが分かる。すなわち、指標Bにより、高周波焼入れ硬化層の脆性破壊のしやすさを整理することができる。
FIG. 3 shows the relationship between the test results of low cycle fatigue strength (in this figure, the bending stress when the number of loads is 5000) and the index B. The test piece has a cylindrical shape with a parallel portion having a diameter of 12 mm, and has a semicircular arc notch in the center. The notch radius R = 1 and the notch bottom diameter is 10 mm. The test method is a load control 4-point bending fatigue test, in which the stress ratio between the maximum load stress and the minimum load stress is 0.1, and the frequency is 5 Hz.
From this figure, it is understood that as the index B is smaller, brittle fracture of the induction-hardened hardened layer is suppressed and the low cycle fatigue strength is improved. That is, by the index B, the ease of brittle fracture of the induction hardened layer can be arranged.
そして、指標A及び指標Bが、A−0.00000293×B≧−14の関係を有する場合に、高周波焼入れ硬化層が脆性破壊することを抑制できる。より高い低サイクル疲労強度レベルを指向する場合は、A−0.00000293×B≧−13の関係を有するのが望ましい。また特に高い低サイクル疲労強度レベルを指向する場合は、A−0.00000293×B≧−12の関係を有するのが望ましい。   And when the parameter | index A and the parameter | index B have a relationship of A-0.00000293 * B> =-14, it can suppress that an induction hardening hardened layer carries out a brittle fracture. When aiming at a higher low cycle fatigue strength level, it is desirable to have a relationship of A−0.00000293 × B ≧ −13. Moreover, when aiming at a particularly high low cycle fatigue strength level, it is desirable to have a relationship of A−0.00000293 × B ≧ −12.
また、上記(B)の過程に移行するか否かは、芯部の靭性も影響する。すなわち芯部の靭性が高いほど硬化層が脆性破壊することを抑制できる。芯部の靭性は、芯部のパーライト、フェライト、及びベイナイトの結晶粒径に依存する。芯部の靭性を確保して硬化層が脆性破壊することを抑制するためには、これらの有効結晶粒径を50μm以下にする必要がある。
Moreover, the toughness of a core part also has an influence whether it transfers to the process of said (B). That is, the higher the toughness of the core, the more the brittle fracture of the hardened layer can be suppressed. The toughness of the core part depends on the crystal grain sizes of pearlite, ferrite, and bainite in the core part. In order to secure the toughness of the core and suppress the brittle fracture of the hardened layer, it is necessary to make these effective crystal grain sizes 50 μm or less .
なお、高周波焼入れ前の組織において、鋼中のフェライト分率は、高周波焼入性を確保する観点から、50%以下である必要がある。
In the structure before induction hardening, the ferrite fraction in the steel needs to be 50% or less from the viewpoint of ensuring induction hardenability .
次に、本発明鋼の成分を限定した理由について説明する。なお、以下の記載において%とは質量%を示す。   Next, the reason which limited the component of this invention steel is demonstrated. In the following description, “%” means “% by mass”.
Cは鋼に必要な強度を与えるのに有効な元素である。ただし、0.35%未満では必要な引張り強度を確保することができず、0.6%を超えると硬くなって高周波焼入れ後の芯部靭性が低下し、また冷間加工性が低下する。このため、Cを0.35〜0.6%の範囲内にする必要がある。   C is an element effective for giving the steel the necessary strength. However, if it is less than 0.35%, the required tensile strength cannot be ensured, and if it exceeds 0.6%, it becomes hard and core toughness after induction hardening is lowered, and cold workability is also lowered. For this reason, C needs to be within a range of 0.35 to 0.6%.
Siは鋼の脱酸に有効な元素であるとともに、鋼に必要な強度及び焼入性を与え、更に焼戻し軟化抵抗を向上させるのに有効な元素である。ただし、0.01%未満ではその効果は不十分であり、1.0%を超えると硬さの上昇を招いて冷間鍛造性を低下させる。このため、Siを0.01〜1.0%の範囲内にする必要がある。冷間加工を受ける鋼材の好適範囲は0.02〜0.3%であるが、特に冷間鍛造性を重視する場合は0.02〜0.13%の範囲内にするのが好ましい。一方、Siは粒界強度の増加に有効な元素であり、また軸受部品、転動部品においては転動疲労過程での組織変化及び材質変化の抑制による高寿命化に有効な元素である。そのため、高強度化を指向する場合には、0.2〜1.0%の範囲が好適である。特に転動疲労強度を高いレベルで求める場合には、0.4〜1.0%の範囲にするのが好ましい。   Si is an element effective for deoxidation of steel, and is an element effective for imparting necessary strength and hardenability to the steel and further improving the temper softening resistance. However, if it is less than 0.01%, the effect is insufficient, and if it exceeds 1.0%, the hardness is increased and the cold forgeability is lowered. For this reason, it is necessary to make Si into the range of 0.01 to 1.0%. The preferable range of the steel material subjected to the cold working is 0.02 to 0.3%, but when the cold forgeability is particularly important, it is preferably within the range of 0.02 to 0.13%. On the other hand, Si is an element effective for increasing the grain boundary strength, and in a bearing part and a rolling part, it is an element effective for extending the life by suppressing the structural change and material change during the rolling fatigue process. Therefore, when aiming at high strength, the range of 0.2 to 1.0% is preferable. In particular, when the rolling fatigue strength is obtained at a high level, it is preferably in the range of 0.4 to 1.0%.
Mnは鋼の脱酸に有効な元素であるとともに、鋼に必要な強度及び焼入れ性を与えるのに有効な元素である。ただし、0.2%未満ではその効果は不十分であり、1.8%を超えるとその効果は飽和するのみならず、硬さの上昇を招いて冷間鍛造性が低下する。このため、Mnを0.2〜1.8%の範囲内にする必要がある。好適な範囲は0.5〜1.2%である。なお、冷間鍛造性を重視する場合には0.5〜0.75%の範囲にするのが好ましい。   Mn is an element effective for deoxidation of steel and is an element effective for imparting the necessary strength and hardenability to the steel. However, if it is less than 0.2%, the effect is insufficient, and if it exceeds 1.8%, the effect is not only saturated, but also the hardness is increased and cold forgeability is lowered. For this reason, it is necessary to make Mn into the range of 0.2 to 1.8%. The preferred range is 0.5-1.2%. In addition, when importance is attached to cold forgeability, it is preferable to set it as 0.5 to 0.75% of range.
Sは鋼中でMnSを形成し、これにより被削性の向上をもたらす。ただし、0.001%未満ではその効果は不十分であり、0.15%を超えるとその効果は飽和する一方で粒界偏析を起こして粒界脆化を招く。このため、Sを0.001〜0.15%の範囲内にする必要がある。なお、軸受部品及び転動部品においてはMnSが転動疲労寿命を劣化させるため、Sを極力低減する必要があり、0.001〜0.01%の範囲にするのが望ましい。   S forms MnS in the steel, thereby improving machinability. However, if the content is less than 0.001%, the effect is insufficient. If the content exceeds 0.15%, the effect is saturated while grain boundary segregation occurs, leading to grain boundary embrittlement. For this reason, S needs to be in the range of 0.001 to 0.15%. In addition, since MnS deteriorates the rolling fatigue life in bearing parts and rolling parts, it is necessary to reduce S as much as possible, and it is desirable to make it in the range of 0.001 to 0.01%.
Alは脱酸材として添加する。ただし、0.001%未満ではその効果は不十分であり、0.05%を超えるとAlNが圧延加熱時に溶体化しないで残存し、TiやNbの析出サイトとなり、これらの析出物の微細分散を阻害して高周波焼入れ時の結晶粒の粗大化を助長する。このため、Alを0.001〜0.05%の範囲内にする必要がある。   Al is added as a deoxidizing material. However, if it is less than 0.001%, the effect is insufficient, and if it exceeds 0.05%, AlN remains without solution during rolling and heating, and becomes a precipitation site for Ti and Nb. Fine dispersion of these precipitates This hinders the coarsening of crystal grains during induction hardening. For this reason, it is necessary to make Al into the range of 0.001 to 0.05%.
Nは鋼中でAl、V、Ti、Nb等と結合して窒化物又は炭窒化物を生成し、結晶粒の粗大化を抑制する。ただし、0.002%未満ではその効果は不十分であり、0.020%を超えるとその効果が飽和するとともに冷間加工性が低下する。このため、Nを0.002〜0.020%の範囲にする必要がある。   N combines with Al, V, Ti, Nb, etc. in the steel to form nitrides or carbonitrides, and suppresses coarsening of crystal grains. However, if it is less than 0.002%, the effect is insufficient, and if it exceeds 0.020%, the effect is saturated and cold workability is lowered. For this reason, it is necessary to make N into the range of 0.002-0.020%.
Pは冷間鍛造時の変形抵抗を高め、かつ靭性を低下させる元素である。また焼入れ、焼戻し後の結晶粒界を脆化させ、疲労強度を低下させる元素である。このため、Pを0.025%以下、好ましくは0.015%以下にする必要がある。   P is an element that increases deformation resistance during cold forging and decreases toughness. Further, it is an element that embrittles crystal grain boundaries after quenching and tempering and reduces fatigue strength. For this reason, P needs to be 0.025% or less, preferably 0.015% or less.
Oは粒界偏析を起こして粒界脆化を起こしやすくするとともに、鋼中で硬い酸化物系介在物を形成して脆性破壊を起こしやすくする元素である。このため、Oを0.0025%以下にする必要がある。   O is an element that causes grain boundary segregation to easily cause grain boundary embrittlement, and forms hard oxide inclusions in the steel to easily cause brittle fracture. For this reason, O needs to be 0.0025% or less.
また、本発明鋼ではCr、Mo、Ni、B、V、Nb、及びTiの一種又は2種以上を含有する。   Further, the steel of the present invention contains one or more of Cr, Mo, Ni, B, V, Nb, and Ti.
Crは鋼に強度及び焼入性を与えるのに有効な元素であり、かつ軸受部品及び転動部品においては転動疲労過程での組織変化及び材質劣化の抑制による高寿命化に有効な元素である。ただし、1.8%を超えて添加すると硬さの上昇を招いて冷間鍛造性が低下する。このため、Crを添加する場合には1.8%以下にする必要がある。尚、実施例における発明鋼のCr量の最小値が0.04%であるので、Cr量の下限を0.04%とする。

Cr is an element effective for imparting strength and hardenability to steel, and in bearing parts and rolling parts, it is an element effective for extending the life by suppressing structural changes and material deterioration during the rolling fatigue process. is there. However, if added over 1.8%, the hardness increases and cold forgeability decreases. For this reason, when adding Cr, it is necessary to make it 1.8% or less. In addition, since the minimum value of the Cr amount of the inventive steel in the examples is 0.04%, the lower limit of the Cr amount is set to 0.04%.

Moも鋼に強度及び焼入性を与えるとともに高周波焼入れ層の靭性向上に有効な元素である。また、軸受部品及び転動部品においては転動疲労過程での組織変化及び材質劣化の抑制による高寿命化に有効な元素である。ただし、1.5%を超えて添加すると硬さの上昇を招いて冷間鍛造性が低下する。このため、Moを添加する場合には1.5%以下にする必要がある。特に0.02〜0.5%の範囲が好適である。   Mo is an element effective for imparting strength and hardenability to the steel and improving the toughness of the induction hardened layer. Further, in bearing parts and rolling parts, it is an element effective for extending the life by suppressing the structural change and material deterioration in the rolling fatigue process. However, if added over 1.5%, the hardness is increased and the cold forgeability is lowered. For this reason, when adding Mo, it is necessary to make it 1.5% or less. A range of 0.02 to 0.5% is particularly suitable.
Niも鋼に強度及び強度及び焼入性を与えるとともに高周波焼入れ層の靭性向上に有効な元素であるが、3.5%を超えて添加すると硬さの上昇を招いて冷間鍛造性が低下する。このため、Niを添加する場合には3.5%以下にする必要がある。特に0.1〜3.5%、更には0.4〜2.0%の範囲が好適である。なお、Ni含有量の下限は、0.1%以上にするのが好ましいが、これに限定されるものではない。   Ni is also an element that gives strength, strength and hardenability to steel and is effective in improving the toughness of the induction hardened layer, but if added over 3.5%, the hardness increases and cold forgeability decreases. To do. For this reason, when adding Ni, it is necessary to make it 3.5% or less. A range of 0.1 to 3.5%, more preferably 0.4 to 2.0% is preferable. The lower limit of the Ni content is preferably 0.1% or more, but is not limited to this.
Bも鋼に強度、焼入性、及び焼戻し軟化抵抗を与えるのに有効な元素であり、かつ高周波焼入れ鋼材の粒界強度を向上させることにより高周波焼入れ部品としての疲労強度及び衝撃強度を向上させる効果も有している。ただし、0.006%を超えるとその効果は飽和し、かつ衝撃強度劣化等の悪影響も生じうる。このため、Bを添加する場合には0.006%以下にする必要がある。特に0.0005〜0.003%の範囲が好適である。   B is also an element effective for imparting strength, hardenability, and temper softening resistance to steel, and improves the fatigue strength and impact strength of induction-hardened parts by improving the grain boundary strength of induction-hardened steel. It also has an effect. However, if it exceeds 0.006%, the effect is saturated, and adverse effects such as impact strength deterioration may occur. For this reason, when adding B, it is necessary to make it 0.006% or less. The range of 0.0005 to 0.003% is particularly suitable.
Vも鋼に強度及び焼入性を与えるのに有効な元素であるが、0.5%を超えて添加すると硬さの上昇を招いて冷間鍛造性が低下する。このため、Vを添加する場合には0.5%以下にする必要がある。特に0.03〜0.5%、更には0.07〜0.2%の範囲が好適である。   V is also an effective element for imparting strength and hardenability to the steel, but if added over 0.5%, the hardness is increased and cold forgeability is reduced. For this reason, when adding V, it is necessary to make it 0.5% or less. In particular, a range of 0.03 to 0.5%, more preferably 0.07 to 0.2% is preferable.
Nbは高周波加熱の際に鋼中のC、Nと結合してNb(CN)を形成し、結晶粒の粗大化を抑制するのに有効な元素であるが、0.04%を超えて添加すると硬さの上昇を招いて冷間鍛造性が低下する。このため、Nbを添加する場合には0.04%以下にする必要がある。特に0.03%以下が好適である。なお、Nbの含有量は0.001%以上であるのが好ましいが、特にこれに限定されるものではない。   Nb combines with C and N in steel during high-frequency heating to form Nb (CN), and is an element effective in suppressing the coarsening of crystal grains, but added in excess of 0.04% As a result, the hardness is increased and the cold forgeability is lowered. For this reason, when adding Nb, it is necessary to make it 0.04% or less. Especially 0.03% or less is suitable. In addition, although it is preferable that content of Nb is 0.001% or more, it is not specifically limited to this.
Tiは鋼中で微細なTiC、TiCSを生成させ、これにより高周波焼入れ時のγ粒の微細化を図ることができる。また、B添加鋼においては、Tiは、鋼中でNと結合してTiNを生成することによるBN析出防止、つまり固溶Bの確保を目的として添加する。ただし、0.2%を超えると、TiCの析出による鋼の硬化が顕著になって冷間加工性が顕著に低下し、かつTiN主体の析出物が多くなって転動疲労特性が低下する。このため、Tiの添加量を0.2%以下にする必要がある。好適範囲は0.1%以下である。   Ti generates fine TiC and TiCS in the steel, thereby making it possible to refine the γ grains during induction hardening. Further, in the B-added steel, Ti is added for the purpose of preventing BN precipitation by forming TiN by combining with N in the steel, that is, ensuring solid solution B. However, if it exceeds 0.2%, the hardening of the steel due to the precipitation of TiC becomes remarkable and the cold workability is remarkably reduced, and the precipitates mainly composed of TiN increase and the rolling fatigue characteristics deteriorate. For this reason, it is necessary to make the addition amount of Ti 0.2% or less. The preferred range is 0.1% or less.
またTiの添加量はNbの添加量に応じて調節するのが好ましい。例えばTi+Nbの好適範囲は0.04%以上0.17%未満である。   Moreover, it is preferable to adjust the addition amount of Ti according to the addition amount of Nb. For example, the preferable range of Ti + Nb is 0.04% or more and less than 0.17%.
次に、本発明鋼の製造方法について説明する。製鋼工程において溶鋼の成分調整を行った後、溶鋼を鋳造する(例えば連続鋳造)ことにより鋳片を製造する。次いで、この鋳片を圧延し、更には必要に応じて熱処理、鍛造、機械加工を行うことにより、所定の高周波焼入れ輪郭部品の形状に加工する。圧延条件、鍛造条件、及びその後の冷却条件を調整することにより鋼中のフェライト分率を上記した範囲にする。その後、高周波焼入れを行い、有効硬化層深さを0.5〜3mmにする。更に必要に応じて焼戻しを行う。   Next, a method for producing the steel of the present invention will be described. After adjusting the components of the molten steel in the steel making process, the molten steel is cast (for example, continuous casting) to produce a slab. Next, this slab is rolled, and further subjected to heat treatment, forging, and machining as necessary to form a predetermined induction-quenched contour part. By adjusting the rolling conditions, the forging conditions, and the subsequent cooling conditions, the ferrite fraction in the steel is set to the above range. Thereafter, induction hardening is performed to make the effective hardened layer depth 0.5 to 3 mm. Further, tempering is performed as necessary.
なお、必要に応じて高周波焼入れ後又は焼戻し後にピーニング処理を行い、靭性を改善してもよい。この場合、表面の残有応力が−500MPa以下となるようにピーニング処理を行うのが好ましい。また、高周波焼入れ硬化層の旧オーステナイト結晶粒度Nγが8〜15番であるのが好ましい。   If necessary, peening may be performed after induction hardening or tempering to improve toughness. In this case, it is preferable to perform the peening treatment so that the residual stress on the surface is −500 MPa or less. Further, the prior austenite grain size Nγ of the induction-hardened hardened layer is preferably No. 8-15.
本発明に規定する各条件を満たすように複数種類の高周波焼き入れ鋼材を形成し、その低サイクル疲労強度を測定した。併せて、比較例として、本発明に規定する範囲から逸出する高周波焼き入れ鋼材についても併せて評価した。
本発明の実施例の試験片は、平行部の直径が12mmの円柱形であり、中央部に半円弧の切り欠きを有している。切り欠き半径R=1であり、切り欠き底直径は10mmである。試験方法は荷重制御4点曲げ疲労試験であり、最大負荷応力と最小負荷応力の応力比は0.1、周波数は5Hzである。
A plurality of types of induction-hardened steel materials were formed so as to satisfy the conditions specified in the present invention, and the low cycle fatigue strength was measured. In addition, as a comparative example, an induction hardened steel material that escapes from the range defined in the present invention was also evaluated.
The test piece according to the embodiment of the present invention has a cylindrical shape with a parallel portion having a diameter of 12 mm, and has a semicircular arc notch in the center portion. The notch radius R = 1 and the notch bottom diameter is 10 mm. The test method is a load control four-point bending fatigue test. The stress ratio between the maximum load stress and the minimum load stress is 0.1, and the frequency is 5 Hz.
結果を図4に示す。図4は、X軸及びY軸それぞれを、3軸応力度指数B及び高周波焼き入れ層の靭性指標Aとしたグラフに、本発明の実施例及び比較例をプロットしたものである。図中の数値は低サイクル疲労強度であり、負荷の回数が5000回で破断する場合の曲げ応力(MPa;実験結果から算出)を示している。
従来用いられている代表的な浸炭歯車であるSCM420浸炭材(Cp=0.9%、表面硬さHV800)の5000回の低サイクル疲労強度は約910〜970MPaである。
The results are shown in FIG. FIG. 4 is a graph in which Examples and Comparative Examples of the present invention are plotted on a graph in which the X axis and the Y axis are the triaxial stress index B and the toughness index A of the induction hardened layer. The numerical value in the figure is the low cycle fatigue strength, and shows the bending stress (MPa; calculated from the experimental results) when the load is broken at 5000 times.
The 5000 low cycle fatigue strength of SCM420 carburized material (Cp = 0.9%, surface hardness HV800), which is a typical carburized gear conventionally used, is about 910 to 970 MPa.
比較例は、A−0.00000293×B<−14となっている。この場合、低サイクル疲労強度は910〜970MPaであり、十分な強度を示していない。
一方、A−0.00000293×B≧−14を満たす実施例では、高周波輪郭焼入れ鋼材の低サイクル疲労強度が1000MPa以上になることが示された。また、A−0.00000293×B≧−13を満たす場合に高周波輪郭焼入れ鋼材の低サイクル疲労強度が1100MPa以上になること、及びA−0.00000293×B≧−12を満たす場合に高周波輪郭焼入れ鋼材の低サイクル疲労強度が1200MPa以上になることも示された。
The comparative example is A−0.00000293 × B <−14. In this case, the low cycle fatigue strength is 910 to 970 MPa, which does not indicate sufficient strength.
On the other hand, in the Example satisfying A−0.00000293 × B ≧ −14, it was shown that the low cycle fatigue strength of the high-frequency contour quenched steel material is 1000 MPa or more. Further, when A-0.00000293 × B ≧ −13 is satisfied, the low-cycle fatigue strength of the high-frequency contour hardened steel is 1100 MPa or more, and when A-0.00000293 × B ≧ −12 is satisfied, high-frequency contour quenching is performed. It was also shown that the low cycle fatigue strength of the steel material is 1200 MPa or more.
以上から、A−0.00000293×B≧−14を満たすことにより、高周波輪郭焼入れ鋼材の低サイクル疲労強度が十分に高くなることが示された。   From the above, it was shown that the low cycle fatigue strength of the high-frequency contour quenched steel material is sufficiently increased by satisfying A−0.00000293 × B ≧ −14.
次に、表1の組成を有する鋼材を溶製し、熱間鍛造で40mmφの棒鋼に鍛造した後、焼準処理を行った。上記棒鋼より、平行部の直径が12mmで、中央部に切り欠き半径R=1の半円弧の切り欠き(切り欠き底直径は10mm)を有する試験片を作製し、種々の条件で浸炭焼入れ焼戻し処理を行った後に低サイクル疲労特性を評価した。試験方法は荷重制御4点曲げ疲労試験であり、最大負荷応力と最小負荷応力の応力比は0.1、周波数は5Hzである。
結果を表2に示す。
Next, a steel material having the composition shown in Table 1 was melted and forged into a 40 mmφ bar steel by hot forging, and then subjected to a normalizing treatment. From the steel bar, a test piece having a parallel arc diameter of 12 mm and a semicircular notch with a notch radius R = 1 at the center (the notch bottom diameter is 10 mm) is prepared and carburized and tempered under various conditions. The low cycle fatigue properties were evaluated after the treatment. The test method is a load control 4-point bending fatigue test, in which the stress ratio between the maximum load stress and the minimum load stress is 0.1, and the frequency is 5 Hz.
The results are shown in Table 2.
本発明例では負荷の回数が5000回の低サイクル疲労強度が1400MPa以上と極めて良好な特性を示すことが明らかである。   In the present invention example, it is clear that the low cycle fatigue strength of 5000 times of loading is 1400 MPa or more and exhibits very good characteristics.
一方、比較例21は、C含有量が本願規定の範囲を下回っており、5000回の低サイクル疲労強度が1000MPa未満である。比較例22,23は、C含有量が本願規定の範囲を上回っており、5000回の低サイクル疲労強度が1000MPa未満である。比較例24は、P含有量が本願規定の範囲を上回っており、5000回の低サイクル疲労強度が1000MPa未満である。比較例25,28は投影芯部硬さが本願発明の範囲を下回った場合であり、5000回の低サイクル疲労強度が1000MPa未満である。比較例26,29はA−0.00000293Bの指標が本願発明の範囲を下回っており、5000回の低サイクル疲労強度が1000MPa未満である。なお、比較例26は高周波焼入れ硬化層の旧オーステナイト結晶粒度Nγが8〜15番の範囲を下回っている。比較例27,30は芯部組織の有効結晶粒径が50μm超であり、5000回の低サイクル疲労強度が1000MPa未満である。なお、比較例30は高周波焼入れ硬化層の旧オーステナイト結晶粒度Nγが8〜15番の範囲を下回っている。   On the other hand, in Comparative Example 21, the C content is below the range specified in the present application, and the 5000 low cycle fatigue strength is less than 1000 MPa. In Comparative Examples 22 and 23, the C content exceeds the range specified in the present application, and the low cycle fatigue strength of 5000 times is less than 1000 MPa. In Comparative Example 24, the P content exceeds the range specified in the present application, and the low cycle fatigue strength of 5000 times is less than 1000 MPa. Comparative Examples 25 and 28 are cases where the projection core hardness is below the range of the present invention, and the low cycle fatigue strength of 5000 times is less than 1000 MPa. In Comparative Examples 26 and 29, the index of A-0.000002293B is below the range of the present invention, and the low cycle fatigue strength of 5000 times is less than 1000 MPa. In Comparative Example 26, the prior austenite grain size Nγ of the induction-hardened hardened layer is below the range of No. 8-15. In Comparative Examples 27 and 30, the effective crystal grain size of the core structure is more than 50 μm, and the low cycle fatigue strength of 5000 times is less than 1000 MPa. In Comparative Example 30, the prior austenite grain size Nγ of the induction-hardened hardened layer is below the range of No. 8-15.
次に、一部の試験片については、アークハイト0.5mmAの条件でジョットピーニング処理を行った。結果を表3に示す。ショットピーニング付与により、表面の残留応力を−500MPa以下にすることにより、さらに優れた低サイクル疲労強度が得られることが明らかである。   Next, about some test pieces, the Giotto peening process was performed on the conditions of arc height 0.5mmA. The results are shown in Table 3. It is clear that by providing shot peening, a further excellent low cycle fatigue strength can be obtained by setting the surface residual stress to −500 MPa or less.
微小亀裂発生時の破壊メカニズムを説明する為の模式図。The schematic diagram for demonstrating the fracture mechanism at the time of microcrack generation | occurrence | production. 破損部位を説明する為の模式図。The schematic diagram for demonstrating a damage site | part. 指標Bと低サイクル疲労試験における寿命の関係を示すグラフ。The graph which shows the relationship between the parameter | index B and the lifetime in a low cycle fatigue test. X軸及びY軸それぞれを、3軸応力度指標B及び高周波焼入れ硬化層の靭性指標Aとした上で、本発明の実施例及び比較例をプロットしたグラフ。The graph which plotted the Example and comparative example of this invention, after making each X-axis and Y-axis into the triaxial stress index B and the toughness index A of the induction hardening hardened layer.

Claims (4)

  1. 質量%で、
    C:0.35〜0.6%、
    Si:0.01〜1.0%、
    Mn:0.2〜1.8%、
    S:0.001〜0.15%、
    Al:0.001〜0.05%、
    N:0.002〜0.020%、
    P:0.025%以下、
    O:0.0025%以下
    Cr:0.04〜1.8%以下、
    含有し、さらに、
    o:1.5%以下、
    Ni:3.5%以下、
    B:0.006%以下、
    V:0.5%以下、
    Nb:0.04%以下、
    Ti:0.2%以下、
    の1種又は2種以上を含有し、残部が鉄及び不可避的不純物からなり、表層に高周波焼入れ処理を施した鋼材であって、
    (ア)高周波焼入れによる有効硬化層深さが0.5〜3mmであり、
    (イ)高周波焼入れ硬化層の旧オーステナイト結晶粒度Nγが8〜15番であり、
    (ウ)芯部のフェライト分率が50%以下であり、
    (エ)芯部組織において、パーライト、フェライト、及びベイナイトの有効結晶粒径が50μm以下であり、
    (オ)下記(1)式で定義される投影芯部硬さHp-coreがHV370以上であり、
    (カ)下記(2)式で定義されるA及び下記(3)式で定義されるBが、A−0.00000293×B≧−14の関係を有することを特徴とする、低サイクル疲労特性に優れた高周波輪郭焼入れ鋼材。
    Hp-core=Hcore/(1−t/r) …(1)
    ただし、Hcore;芯部硬さ、t;有効硬化層深さ、r;破損部位の半径または破損部位の肉厚の半分である。
    A=Mo+0.227Ni+190B−7.18C−0.087Si−17.2P−2.74V−0.00955Hs+0.0344Nγ …(2)
    ただし、Hs;表面硬さ(HV)、Nγ;高周波焼入れ硬化層の旧オーステナイト結晶粒度。
    B=t×(Hcore) … (3)
    % By mass
    C: 0.35-0.6%
    Si: 0.01 to 1.0%,
    Mn: 0.2-1.8%
    S: 0.001 to 0.15%,
    Al: 0.001 to 0.05%,
    N: 0.002 to 0.020%,
    P: 0.025% or less,
    O: 0.0025% or less ,
    Cr: 0.04 to 1.8% or less,
    It contains, in addition,
    M o: 1.5% or less,
    Ni: 3.5% or less,
    B: 0.006% or less,
    V: 0.5% or less,
    Nb: 0.04% or less,
    Ti: 0.2% or less,
    Is a steel material containing one or more of the following, the balance consisting of iron and inevitable impurities, and subjected to induction hardening treatment on the surface layer,
    (A) the effective case depth by induction hardening is 0.5 to 3 mm,
    (B) The prior austenite grain size Nγ of the induction-hardened hardened layer is No. 8-15,
    (C) The ferrite fraction of the core is 50% or less,
    (D) In the core structure, the effective crystal grain size of pearlite, ferrite, and bainite is 50 μm or less,
    (E) below (1) Ri der projection core hardness Hp-core is HV370 or more defined by the equation,
    (F) Low cycle fatigue characteristics, wherein A defined by the following formula (2) and B defined by the following formula (3) have a relationship of A−0.00000293 × B ≧ −14 High-frequency contour hardened steel.
    Hp-core = Hcore / (1-t / r) (1)
    Where Hcore: core hardness, t: effective hardened layer depth, r: half of the radius of the damaged part or the thickness of the damaged part.
    A = Mo + 0.227Ni + 190B-7.18C-0.087Si-17.2P-2.74V-0.00955Hs + 0.0344Nγ (2)
    Where Hs: surface hardness (HV), Nγ: prior austenite grain size of induction hardened layer.
    B = t × (Hcore) 2 (3)
  2. 表面の残留応力が−500MPa以下であることを特徴とする請求項1に記載の低サイクル疲労特性に優れた高周波輪郭焼入れ鋼材。 The high frequency contour hardened steel material having excellent low cycle fatigue characteristics according to claim 1, wherein the surface has a residual stress of −500 MPa or less.
  3. 請求項1または2に記載の高周波輪郭焼入れ鋼材を用いた高周波輪郭焼入れ部品。 A high-frequency contour-quenched part using the high-frequency contour-quenched steel material according to claim 1 or 2 .
  4. 前記高周波輪郭焼入れ部品は歯車であることを特徴とする請求項に記載の高周波輪郭焼入れ部品。 The induction hardening component according to claim 3 , wherein the induction hardening component is a gear.
JP2006167569A 2006-06-16 2006-06-16 Induction contour hardened steel and induction contour hardened parts with excellent low cycle fatigue characteristics Active JP4728884B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2006167569A JP4728884B2 (en) 2006-06-16 2006-06-16 Induction contour hardened steel and induction contour hardened parts with excellent low cycle fatigue characteristics

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2006167569A JP4728884B2 (en) 2006-06-16 2006-06-16 Induction contour hardened steel and induction contour hardened parts with excellent low cycle fatigue characteristics

Related Child Applications (1)

Application Number Title Priority Date Filing Date
JP2010248690A Division JP5505264B2 (en) 2010-11-05 2010-11-05 Induction contour hardened steel and induction contour hardened parts with excellent low cycle fatigue characteristics

Publications (2)

Publication Number Publication Date
JP2007332439A JP2007332439A (en) 2007-12-27
JP4728884B2 true JP4728884B2 (en) 2011-07-20

Family

ID=38932190

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2006167569A Active JP4728884B2 (en) 2006-06-16 2006-06-16 Induction contour hardened steel and induction contour hardened parts with excellent low cycle fatigue characteristics

Country Status (1)

Country Link
JP (1) JP4728884B2 (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP6043079B2 (en) * 2012-03-30 2016-12-14 株式会社神戸製鋼所 Steel for gears for induction heat treatment excellent in hot forgeability and gear cutting workability, and gears and methods for producing the gears
CN111304539B (en) * 2020-04-09 2021-02-09 莆田学院 High-speed high-power-density motor rotating shaft and preparation method thereof

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08283910A (en) * 1995-04-17 1996-10-29 Nippon Steel Corp Steel material for induction hardened shaft parts, combining cold workability with torsional fatigue strength characteristic
JPH1017928A (en) * 1996-06-28 1998-01-20 Kawasaki Steel Corp Production of gear steel stock for induction hardening, excellent in machinability and fatigue strength
JPH10195589A (en) * 1996-12-26 1998-07-28 Nippon Steel Corp Induction hardened steel material with high torsional fatigue strength
JPH11302727A (en) * 1998-04-17 1999-11-02 Sanyo Special Steel Co Ltd Production of high strength shaft

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08283910A (en) * 1995-04-17 1996-10-29 Nippon Steel Corp Steel material for induction hardened shaft parts, combining cold workability with torsional fatigue strength characteristic
JPH1017928A (en) * 1996-06-28 1998-01-20 Kawasaki Steel Corp Production of gear steel stock for induction hardening, excellent in machinability and fatigue strength
JPH10195589A (en) * 1996-12-26 1998-07-28 Nippon Steel Corp Induction hardened steel material with high torsional fatigue strength
JPH11302727A (en) * 1998-04-17 1999-11-02 Sanyo Special Steel Co Ltd Production of high strength shaft

Also Published As

Publication number Publication date
JP2007332439A (en) 2007-12-27

Similar Documents

Publication Publication Date Title
JP4728883B2 (en) Carburized and hardened steel and carburized parts with excellent low cycle fatigue properties
JP5862802B2 (en) Carburizing steel
US9890446B2 (en) Steel for induction hardening roughly shaped material for induction hardening
JP4415219B2 (en) Age hardened steel
JP4257539B2 (en) Non-tempered steel for soft nitriding
JP4385019B2 (en) Manufacturing method for steel nitrocarburized machine parts
JP5505263B2 (en) Carburized and hardened steel and carburized parts with excellent low cycle fatigue properties
JP4847681B2 (en) Ti-containing case-hardened steel
WO2019244503A1 (en) Mechanical component
JP6631640B2 (en) Case hardened steel, carburized parts and method of manufacturing case hardened steel
JP3094856B2 (en) High strength, high toughness case hardening steel
JPH11236644A (en) Steel for induction hardening excellent in high strength characteristic and low heat treating strain characteristic and its production
JP3842888B2 (en) Method of manufacturing steel for induction hardening that combines cold workability and high strength properties
JP4728884B2 (en) Induction contour hardened steel and induction contour hardened parts with excellent low cycle fatigue characteristics
WO2017056896A1 (en) Preform for crankshaft, nitride crankshaft, and manufacturing method for same
JP6433341B2 (en) Age-hardening bainite non-tempered steel
JP5131770B2 (en) Non-tempered steel for soft nitriding
JP2009191322A (en) Case-hardened steel superior in grain-coarsening resistance for use in carburized parts
JP5505264B2 (en) Induction contour hardened steel and induction contour hardened parts with excellent low cycle fatigue characteristics
JP6635100B2 (en) Case hardened steel
JP4828321B2 (en) Induction hardened steel and induction hardened parts with excellent low cycle fatigue properties
KR20190008915A (en) Progressive steel and its manufacturing method and manufacturing method of gear parts
JP2009270160A (en) Method for producing steel material for soft-nitriding
JP2007231348A (en) Steel material having excellent fatigue property and its production method
JP2015212414A (en) Steel for cold-forged component

Legal Events

Date Code Title Description
A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20080807

A977 Report on retrieval

Free format text: JAPANESE INTERMEDIATE CODE: A971007

Effective date: 20100826

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20100907

A521 Written amendment

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20101105

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: 20110405

A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

A61 First payment of annual fees (during grant procedure)

Free format text: JAPANESE INTERMEDIATE CODE: A61

Effective date: 20110415

R151 Written notification of patent or utility model registration

Ref document number: 4728884

Country of ref document: JP

Free format text: JAPANESE INTERMEDIATE CODE: R151

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20140422

Year of fee payment: 3

S533 Written request for registration of change of name

Free format text: JAPANESE INTERMEDIATE CODE: R313533

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20140422

Year of fee payment: 3

R350 Written notification of registration of transfer

Free format text: JAPANESE INTERMEDIATE CODE: R350

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20140422

Year of fee payment: 3

S533 Written request for registration of change of name

Free format text: JAPANESE INTERMEDIATE CODE: R313533

R350 Written notification of registration of transfer

Free format text: JAPANESE INTERMEDIATE CODE: R350