JP2005325398A - High-strength gear and manufacturing method therefor - Google Patents
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Abstract
Description
この発明は、自動車や各種産業機器等に使用される、高い曲げ疲労強度および面圧疲労強度を有する高強度歯車およびその製造方法に関するものである。 The present invention relates to a high-strength gear having high bending fatigue strength and surface fatigue strength used for automobiles and various industrial equipment, and a method for manufacturing the same.
自動車等に用いられている歯車には、近年、省エネルギー化による車体重量の軽量化に伴って、サイズの小型化が要求され、また、エンジンの高出力化に伴って歯車にかかる負荷が増大している。歯車の耐久性は、主に歯元の曲げ疲労破壊ならびに歯面の面圧疲労破壊によって決まる。 In recent years, gears used in automobiles and the like have been required to be smaller in size as the weight of the vehicle body has been reduced due to energy saving, and the load on the gears has increased as the output of the engine has increased. ing. The durability of a gear is mainly determined by the bending fatigue failure of the tooth root and the surface pressure fatigue failure of the tooth surface.
従来、歯車は、ＪＩＳ ＳＣＭ４２０Ｈ、ＳＣＭ８２２Ｈ等により規定された肌焼鋼を用いて歯車材を調製し、この歯車材に浸炭等の表面処理を施して製造されていた。しかしながら、このような歯車は、高応力下での使用に耐えられるものではないことから、鋼材の変更、熱処理方法の変更、表面の加工硬化処理等によって、歯元曲げ疲労強度、耐ピッチング性の向上を図っていた。 Conventionally, gears have been manufactured by preparing gear materials using case-hardened steel defined by JIS SCM420H, SCM822H, etc., and subjecting the gear materials to surface treatment such as carburization. However, such gears cannot withstand use under high stress, and therefore, by changing steel materials, changing heat treatment methods, surface work hardening treatments, etc., tooth root bending fatigue strength and pitting resistance can be improved. I was trying to improve.
例えば、特公平０７−１２２１１８号公報（特許文献１）には、鋼中のＳｉを低減して、Ｍｎ、Ｃｒ、Ｍｏ、Ｎｉをコントロールすることにより、浸炭熱処理後の表面の粒界酸化層を低減して亀裂の発生を少なくし、不完全焼入層生成を抑制することにより、表面硬さの低減を抑えて疲労強度を高め、さらに、Ｃａを添加して、亀裂の発生・伝播を助長するＭｎＳの延伸を制御する方法が開示されている。以下、この方法を先行技術１という。 For example, in Japanese Patent Publication No. 07-122118 (Patent Document 1), by reducing Si in steel and controlling Mn, Cr, Mo and Ni, a grain boundary oxide layer on the surface after carburizing heat treatment is provided. By reducing the generation of cracks and suppressing the generation of incompletely hardened layers, the reduction of surface hardness is suppressed and the fatigue strength is increased. Furthermore, Ca is added to promote the generation and propagation of cracks. A method for controlling the stretching of MnS is disclosed. Hereinafter, this method is referred to as Prior Art 1.
また、特許第２９４５７１４号公報（特許文献２）には、素材としてＳｉを０．２５〜１．５０％添加した鋼材を用いて焼戻し軟化抵抗を高める方法が開示されている。以下、この方法を先行技術２という。
Japanese Patent No. 2945714 (Patent Document 2) discloses a method of increasing temper softening resistance using a steel material to which 0.25 to 1.50% of Si is added as a material. Hereinafter, this method is referred to as Prior
しかしながら、上述した先行技術には、下記の問題があった。 However, the above-described prior art has the following problems.
先行技術１によれば、Ｓｉを低減することにより、粒界酸化層および不完全焼入れ層が低減するので、歯元での曲げ疲労亀裂発生を抑えることはできる。しかし、逆に焼戻し軟化抵抗が低下して、破壊の発生が歯元から歯面側に移行する結果、歯面での摩擦熱による焼戻し軟化を抑えることができなくなって表面が軟化する。このために、ピッチングが発生しやすくなるという問題があった。 According to Prior Art 1, since the grain boundary oxide layer and the incompletely hardened layer are reduced by reducing Si, it is possible to suppress the occurrence of bending fatigue cracks at the tooth root. However, the temper softening resistance decreases, and the occurrence of fracture shifts from the tooth base to the tooth surface. As a result, temper softening due to frictional heat on the tooth surface cannot be suppressed, and the surface softens. For this reason, there has been a problem that pitching is likely to occur.
先行技術２では、焼戻し軟化抵抗を上げるために逆にＳｉ等を添加し、粒界酸化進行の抑制のために浸炭工法を真空浸炭あるいはプラズマ浸炭等に限定しているが、この方法は、製造コストが上がるので量産化に不適である。
In
従って、この発明の目的は、上述した問題を解決して、歯元曲げ疲労強度が従来の歯車よりも高く、さらに、面圧疲労特性に優れた量産可能な高強度歯車およびその製造方法を提供することにある。 Accordingly, an object of the present invention is to solve the above-described problems, and provide a high-strength gear capable of mass production that has a higher root bending fatigue strength than that of a conventional gear and that is excellent in surface pressure fatigue characteristics, and a method for manufacturing the same. There is to do.
本願発明者等は、上述した課題を解決するために、鋭意、研究を重ねた結果、以下の知見を得た。 The inventors of the present application have earnestly studied to solve the above-mentioned problems, and as a result, obtained the following knowledge.
（１）鋼材中のＳｉ、Ｃｒを増量することによって、焼戻し軟化抵抗を高めると共に、歯車接触面での発熱による軟化を抑えれば、歯車駆動時に生じる歯面の亀裂発生を抑制することができる。 (1) By increasing the amount of Si and Cr in the steel material, the temper softening resistance is increased, and if the softening due to heat generation at the gear contact surface is suppressed, the generation of cracks in the tooth surface that occurs during gear driving can be suppressed. .
（２）曲げ疲労および疲労亀裂の起点となり得る粒界酸化層については、Ｓｉをある量以上添加することにより、粒界酸化層の成長方向が深さ方向から表面の密度増加方向に変わる。従って、起点となるような深さ方向に成長した酸化層がなくなるので、曲げ疲労および疲労亀裂の起点となりにくくなる。さらに、この酸化層は、剥離し易くなり、ショットピーニングによりほぼ剥離して無くなるために、影響がでない。 (2) For the grain boundary oxide layer that can be the starting point of bending fatigue and fatigue cracks, the growth direction of the grain boundary oxide layer changes from the depth direction to the surface density increase direction by adding a certain amount or more of Si. Therefore, since there is no oxide layer grown in the depth direction as a starting point, it becomes difficult to be a starting point for bending fatigue and fatigue cracks. Furthermore, this oxide layer is easy to peel off, and is almost unpeeled by shot peening, so there is no influence.
（３）上記（１）および（２）の通り、Ｓｉは、焼戻し軟化抵抗の向上と粒界酸化層のコントロールに有効であるが、その両方を満たすためのＳｉ量の適正値がある。 (3) As described in the above (1) and (2), Si is effective in improving the temper softening resistance and controlling the grain boundary oxide layer, but there is an appropriate value of the Si amount to satisfy both.
（４）歯面の浸炭部表面は、マルテンサイトおよび４０体積％以下の残留オーステナイトにすることにより硬度低下を抑制できる。また、表層のＣ含有量は、０．９ｍａｓｓ％未満にして表層の粒界セメンタイトの生成を抑えることによって、曲げ疲労および面圧疲労での疲労亀裂の発生を抑えることができる。 (4) The surface of the carburized portion of the tooth surface can be reduced in hardness by using martensite and retained austenite of 40% by volume or less. Further, the generation of fatigue cracks in bending fatigue and surface pressure fatigue can be suppressed by setting the C content of the surface layer to less than 0.9 mass% and suppressing the formation of grain boundary cementite in the surface layer.
この発明は、上記知見に基づきなされたものであって、下記を特徴とするものである。 The present invention has been made on the basis of the above findings, and is characterized by the following.
請求項１記載の発明は、Ｃ：０．１０〜０．２５％、Ｓｉ：０．８〜１．２％、Ｍｎ：０．６〜２．０％、Ｓ：０．００６％以上、Ｃｒ：１．０〜２．０％、Ｍｏ：０．２〜０．８％、Ａｌ：０．００５〜０．２００％、Ｎ：０．００５０〜０．０２００％（以上、ｍａｓｓ％）を含有し、残部がＦｅおよび不可避的不純物からなる鋼材を、鍛造あるいは機械加工により歯車形状に形成したものからなり、歯車形状に形成後、浸炭処理あるいは浸炭窒化処理を施した時の、表層のＣ含有量が０．９ｍａｓｓ％未満、歯車の表層から１００μｍ深さ位置までの残留オーステナイト量が４０体積％以下、且つ、組織がマルテンサイト単相であることに特徴を有するものである。 The invention according to claim 1 includes C: 0.10 to 0.25%, Si: 0.8 to 1.2%, Mn: 0.6 to 2.0%, S: 0.006% or more, Cr : 1.0-2.0%, Mo: 0.2-0.8%, Al: 0.005-0.200%, N: 0.0050-0.0200% (above, mass%) contained In addition, the steel material comprising the balance Fe and inevitable impurities is formed into a gear shape by forging or machining, and after forming into a gear shape, carburizing treatment or carbonitriding treatment is performed, and C content in the surface layer The amount is less than 0.9 mass%, the amount of retained austenite from the surface layer of the gear to the depth of 100 μm is 40% by volume or less, and the structure is characterized by a martensite single phase.
請求項２記載の発明は、請求項１記載の発明において、鋼材は、Ｎｂ：０．０１０〜０．０６０％、Ｖ：０．０５〜０．２０％（以上、ｍａｓｓ％）の少なくとも１種をさらに含有していることに特徴を有するものである。
The invention according to
請求項３記載の発明は、請求項１または２記載の発明において、鋼材は、Ｔｉ：０．００５〜０．０５０％、Ｂ：０．０００５〜０．０１００％（以上、ｍａｓｓ％）をさらに含有していることに特徴を有するものである。
The invention according to claim 3 is the invention according to
請求項４記載の発明は、Ｃ：０．１０〜０．２５％、Ｓｉ：０．８〜１．２％、Ｍｎ：０．６〜２．０％、Ｓ：０．００６％以上、Ｃｒ：１．０〜２．０％、Ｍｏ：０．２〜０．８％、Ａｌ：０．００５〜０．２００％、Ｎ：０．００５０〜０．０２００％（以上、ｍａｓｓ％）を含有し、残部がＦｅおよび不可避的不純物からなる鋼材を、鍛造あるいは機械加工により歯車形状に形成して歯車材を調製し、次いで、前記歯車材に浸炭処理あるいは浸炭窒化処理を施し、さらに、アークハイト０．３ｍｍＡ以上のショットピーニングを施して、表層のＣ含有量を０．９ｍａｓｓ％未満、歯車の表層から１００μｍ深さ位置までの残留オーステナイト量を４０体積％以下、且つ、組織をマルテンサイト単相とすることに特徴を有するものである。 Invention of Claim 4 is C: 0.10-0.25%, Si: 0.8-1.2%, Mn: 0.6-2.0%, S: 0.006% or more, Cr : 1.0-2.0%, Mo: 0.2-0.8%, Al: 0.005-0.200%, N: 0.0050-0.0200% (above, mass%) contained Then, a steel material having the balance of Fe and inevitable impurities is formed into a gear shape by forging or machining to prepare a gear material, and then the carburizing treatment or carbonitriding treatment is applied to the gear material, and the arc height is further increased. Shot peening of 0.3 mmA or more is performed, the C content of the surface layer is less than 0.9 mass%, the amount of retained austenite from the surface layer of the gear to the 100 μm depth position is 40% by volume or less, and the structure is a martensite single phase. Is characterized by
請求項５記載の発明は、請求項４記載の発明において、鋼材として、Ｎｂ：０．０１０〜０．０６０％、Ｖ：０．０５〜０．２０％（以上、ｍａｓｓ％）の少なくとも１種をさらに含有したものを使用することに特徴を有するものである。
The invention according to
請求項６記載の発明は、請求項４または５記載の発明において、鋼材として、Ｔｉ：０．００５〜０．０５０％、Ｂ：０．０００５〜０．０１００％（以上、ｍａｓｓ％）をさらに含有するものを使用することに特徴を有するものである。
The invention according to claim 6 is the invention according to
この発明によれば、曲げ疲労特性および面圧疲労特性に優れた、３０００ＭＰａ以上の高面圧を必要とする自動車や各種産業機器等に使用される歯車を製造することができる。 According to the present invention, it is possible to manufacture a gear that is excellent in bending fatigue characteristics and surface pressure fatigue characteristics and that is used in automobiles, various industrial equipment, and the like that require a high surface pressure of 3000 MPa or more.
以下に、各限定理由について述べる。 Below, each reason for limitation is described.
Ｃ：０．１０〜０．２５ｍａｓｓ％
Ｃは、強度確保のために必要であり、その量は、浸炭焼戻し後の内部硬さを決定するが、その量が０．１０ｍａｓｓ％未満では、内部の硬さが低下しすぎるために歯車としての強度を確保できない。一方、０．２５ｍａｓｓ％を超えると、歯車内部の靭性が低下して、疲労亀裂が進展しやすくなるため曲げ疲労特性が低下するばかりでなく、加工性の劣化が起る。従って、Ｃ含有量は、０．１０〜０．２５ｍａｓｓ％の範囲内に限定した。
C: 0.10 to 0.25 mass%
C is necessary for securing the strength, and the amount thereof determines the internal hardness after carburizing and tempering. However, if the amount is less than 0.10 mass%, the internal hardness is excessively reduced, so that the gear is used. Can not secure the strength of. On the other hand, if it exceeds 0.25 mass%, the toughness inside the gear is lowered and fatigue cracks are likely to progress, so that not only the bending fatigue characteristics are lowered, but also workability is deteriorated. Therefore, the C content is limited to a range of 0.10 to 0.25 mass%.
Ｓｉ：０．８〜１．２ｍａｓｓ％
Ｓｉは、焼戻し軟化抵抗を高めるのに有効な元素であると共に、粒界酸化層深さを抑える効果がある。軟化抵抗が低いと、歯車駆動時に歯車同士の摩擦により歯車表層が焼戻され軟化して、面圧疲労特性が低下する。粒界酸化層深さが大きいと疲労起点となりやすいために曲げ疲労特性、面圧疲労特性の何れも低下する。
Si: 0.8-1.2 mass%
Si is an element effective for increasing the temper softening resistance and has an effect of suppressing the depth of the grain boundary oxide layer. If the softening resistance is low, the gear surface layer is tempered and softened by friction between the gears when the gears are driven, and the surface pressure fatigue characteristics are deteriorated. If the grain boundary oxide layer depth is large, it tends to become a fatigue starting point, so both the bending fatigue characteristics and the surface pressure fatigue characteristics are lowered.
Ｓｉの適正範囲を調べるために、以下の試験を行った。 In order to investigate the appropriate range of Si, the following tests were conducted.
Ｓｉ添加量だけを変更して材料を溶解し、それらの材料に図１に示すパターンに従って浸炭処理を行い回転曲げ疲労試験を行った。また、図２に示す形状および寸法の試験片を用いて面圧疲労特性の指標であるローラーピッチング試験を行った。さらに、それぞれの材料について３００℃での焼戻しによる軟化量および粒界酸化層深さを調査した。 Only the amount of Si added was changed to dissolve the materials, and these materials were subjected to carburizing treatment according to the pattern shown in FIG. In addition, a roller pitching test, which is an index of surface pressure fatigue characteristics, was performed using a test piece having the shape and dimensions shown in FIG. Furthermore, the softening amount and the grain boundary oxide layer depth by tempering at 300 ° C. were investigated for each material.
曲げ疲労強度を粒界酸化層深さで整理した結果を図３に示す。図３から粒界酸化層が１０μｍ以下になると、曲げ疲労強度が向上することが分かった。 The result of arranging the bending fatigue strength by the grain boundary oxide layer depth is shown in FIG. FIG. 3 indicates that the bending fatigue strength is improved when the grain boundary oxide layer is 10 μm or less.
次に、面圧疲労強度を３００℃焼戻し軟化量で整理した結果を図４に示す。図４から３００℃焼戻しによる軟化量ΔＨＶが１００ＨＶ以下で面圧疲労強度が向上することが分かった。 Next, FIG. 4 shows the results of arranging the surface pressure fatigue strength by the temper softening amount at 300 ° C. From FIG. 4, it was found that the surface pressure fatigue strength is improved when the softening amount ΔHV by tempering at 300 ° C. is 100 HV or less.
図５に、Ｓｉ量と粒界酸化層深さおよび３００℃焼戻し軟化量との関係を示す。 FIG. 5 shows the relationship between the Si amount, the grain boundary oxide layer depth, and the 300 ° C. temper softening amount.
図５から、Ｓｉは、歯面の摩擦による発熱程度の温度である３００℃での焼戻しにおいて、硬度低下抑制には、０．８ｍａｓｓ％以上で効果があることが分かり、２．０ｍａｓｓ％を超えると効果が飽和することが分かった。 From FIG. 5, it can be seen that Si has an effect of suppressing hardness reduction at 0.8 mass% or more in tempering at 300 ° C., which is about the temperature of heat generation due to friction of the tooth surface, and exceeds 2.0 mass%. And the effect was saturated.
図５から粒界酸化層深さに及ぼすＳｉ量は、０．１ｍａｓｓ％以下および０．６ｍａｓｓ％以上で効果があることが分かった。また、１．２ｍａｓｓ％を超えるとその効果は飽和することが分かった。 From FIG. 5, it was found that the effect of Si amount on the grain boundary oxide layer depth was 0.1 mass% or less and 0.6 mass% or more. Moreover, it turned out that the effect will be saturated when it exceeds 1.2 mass%.
以上の実験結果から、粒界酸化層深さおよび３００℃焼戻し軟化量の両方の効果が得られるＳｉ添加量の範囲は、０．８〜１．２ｍａｓｓ％であり、０．８ｍａｓｓ％未満では、面圧疲労強度の向上が図れず、１．２ｍａｓｓ％を超えて添加してもこれらの効果は飽和してしまうためにコスト的に無駄である。従って、Ｓｉ含有量は、０．８〜１．２ｍａｓｓ％の範囲内に限定した。 From the above experimental results, the range of Si addition amount in which both the grain boundary oxide layer depth and the 300 ° C. temper softening effect can be obtained is 0.8 to 1.2 mass%, and less than 0.8 mass%, The surface fatigue strength cannot be improved, and even if added over 1.2 mass%, these effects are saturated, and this is wasteful in cost. Therefore, the Si content is limited to the range of 0.8 to 1.2 mass%.
Ｍｎ：０．６〜２．０ｍａｓｓ％
Ｍｎは、鋼の焼入れ性を高める元素である。焼入れ性を確保するためには、Ｍｎの添加量は、０．６ｍａｓｓ％以上必要であるが、２．０ｍａｓｓ％を超えて添加しても過剰に焼入れ性が上がり、残留オーステナイト量が過多となって硬さの低下を招くばかりなので、Ｍｎ添加量の上限は、２．０ｍａｓｓ％とした。
Mn: 0.6 to 2.0 mass%
Mn is an element that enhances the hardenability of steel. In order to ensure hardenability, the amount of Mn added must be 0.6 mass% or more, but even if added over 2.0 mass%, the hardenability is excessively increased and the amount of retained austenite becomes excessive. Therefore, the upper limit of the Mn addition amount is set to 2.0 mass%.
Ｓ：０．００６ｍａｓｓ％以上
Ｓは、Ｍｎと結合してＭｎＳを形成し、被削性を向上させる効果を持つが、０．００６ｍａｓｓ％未満では、生成するＭｎＳが少なすぎてその効果が現われない。従って、Ｓ含有量は、０．００６ｍａｓｓ％以上に限定した。
S: 0.006 mass% or more S combines with Mn to form MnS and has an effect of improving machinability. However, if it is less than 0.006 mass%, the generated MnS is so small that the effect does not appear. . Therefore, the S content is limited to 0.006 mass% or more.
Ｃｒ：１．０〜２．０ｍａｓｓ％
Ｃｒは、焼入れ性向上元素であると共に、焼戻し軟化抵抗を高める元素である。両方の性能を発揮させるには１．０ｍａｓｓ％以上の添加が必要である。しかし、その添加量が２．０ｍａｓｓ％を超えると、軟化抵抗を高める効果は飽和して焼入れ性が高くなりすぎる。このため歯車内部の靭性が劣化して、疲労亀裂の進展が早くなるために曲げ疲労強度が低下する。従って、Ｃｒ含有量は、１．０〜２．０ｍａｓｓ％の範囲内に限定した。
Cr: 1.0-2.0 mass%
Cr is an element that enhances hardenability and increases temper softening resistance. In order to exhibit both performances, addition of 1.0 mass% or more is necessary. However, when the addition amount exceeds 2.0 mass%, the effect of increasing the softening resistance is saturated and the hardenability becomes too high. For this reason, the toughness inside the gears deteriorates and the fatigue cracks progress more quickly, so the bending fatigue strength decreases. Therefore, the Cr content is limited to a range of 1.0 to 2.0 mass%.
Ｍｏ：０．２〜０．８ｍａｓｓ％
Ｍｏは、焼入れ性向上元素である。そのためには０．２ｍａｓｓ％以上の添加が必要であるが、０．８ｍａｓｓ％を超えて添加してもその効果は飽和し、しかも、高価な合金であるので経済性も悪い。従って、Ｍｏ含有量は、０．２〜０．８ｍａｓｓ％の範囲内に限定した。
Mo: 0.2-0.8 mass%
Mo is a hardenability improving element. For that purpose, addition of 0.2 mass% or more is necessary, but even if added in excess of 0.8 mass%, the effect is saturated, and since it is an expensive alloy, the economy is poor. Therefore, the Mo content is limited to the range of 0.2 to 0.8 mass%.
Ａｌ：０．００５〜０．２００ｍａｓｓ％
Ａｌは、脱酸に有効な元素であり、その効果は、０．００５ｍａｓｓ％以上の添加で発揮される。また、Ｎと結合してＡｌＮを生成し、結晶粒の粗大化を抑える働きがある。その効果は、０．２００ｍａｓｓ％までの添加で有効であり、それを超えると粗大粒が発生して疲労亀裂が進展しやすくなるために、曲げ疲労強度および面圧疲労強度が低下する。従って、Ａｌ含有量は、０．００５〜０．２００ｍａｓｓ％の範囲内に限定した。
Al: 0.005 to 0.200 mass%
Al is an element effective for deoxidation, and the effect is exhibited by addition of 0.005 mass% or more. In addition, it combines with N to produce AlN, and has a function of suppressing coarsening of crystal grains. The effect is effective when added up to 0.200 mass%, and if it exceeds that, coarse grains are generated and fatigue cracks tend to progress, so that the bending fatigue strength and the surface pressure fatigue strength are reduced. Therefore, the Al content is limited to a range of 0.005 to 0.200 mass%.
Ｎ：０．００５０〜０．０２００ｍａｓｓ％
Ｎは、Ａｌと結合してＡｌＮを生成し、結晶粒の粗大化を抑えて疲労強度を向上させる。その効果を得るには０．００５ｍａｓｓ％以上必要であるが、０．０２００ｍａｓｓ％を超えるとその効果は飽和するだけでなく、内部にブローボール等の欠陥を発生させ、結果的に曲げ疲労強度の低下を招く。従って、Ｎ含有量は、０．００５〜０．０２００ｍａｓｓ％の範囲内に限定した。
N: 0.0050-0.0200 mass%
N combines with Al to produce AlN, and suppresses coarsening of crystal grains to improve fatigue strength. In order to obtain the effect, 0.005 mass% or more is necessary. However, if it exceeds 0.0200 mass%, the effect is not only saturated, but also defects such as blow balls are generated inside, resulting in bending fatigue strength. Incurs a decline. Therefore, the N content is limited to a range of 0.005 to 0.0200 mass%.
Ｎｂ：０．０１０〜０．０６０ｍａｓｓ％
Ｎｂは、炭窒化物形成により結晶粒を微細化させる。これにより歯元曲げ疲労強度の向上が図られる。結晶粒を微細化させるには０．０１０ｍａｓｓ％以上必要であり、０．０６０ｍａｓｓ％以上添加してもその効果は飽和してしまう。従って、Ｎｂ含有量は、０．０１０〜０．０６０ｍａｓｓ％の範囲内に限定した。
Nb: 0.010 to 0.060 mass%
Nb refines crystal grains by forming carbonitrides. As a result, the root bending fatigue strength is improved. In order to refine crystal grains, 0.010 mass% or more is necessary, and the effect is saturated even if 0.060 mass% or more is added. Therefore, the Nb content is limited to the range of 0.010 to 0.060 mass%.
Ｖ：０．０５〜０．２０ｍａｓｓ％
Ｖは、Ｓｉ、Ｃｒと同じく焼戻し軟化抵抗を高める。また、それと同時に炭窒化物を形成して結晶粒の微細化を行いＳｉの偏析を抑制する効果も持っている。その効果を発揮させるためには、０．０５ｍａｓｓ％以上の添加が必要である。しかし、この効果は、０．２０ｍａｓｓ％を超えて添加しても飽和してしまい、十分な効果は得られず、製造コストが上がるだけである。従って、Ｖ含有量は、０．０５〜０．２０ｍａｓｓ％の範囲内に限定した。
V: 0.05-0.20 mass%
V increases the temper softening resistance in the same manner as Si and Cr. At the same time, carbonitrides are formed to refine crystal grains and to suppress the segregation of Si. In order to exhibit the effect, addition of 0.05 mass% or more is necessary. However, this effect is saturated even if added in excess of 0.20 mass%, a sufficient effect cannot be obtained, and the manufacturing cost only increases. Therefore, the V content is limited to the range of 0.05 to 0.20 mass%.
Ｔｉ：０．００５〜０．０５０ｍａｓｓ％、Ｂ：０．０００５〜０．０１００ｍａｓｓs％
Ｂは、焼入れ性を上げるのに有効である。その効果は、０．０００５ｍａｓｓ％以上で得られ、０．０１００ｍａｓｓ％を超えると飽和してしまう。従って、Ｂ含有量は、０．０００５〜０．０１００ｍａｓｓ％の範囲内に限定した。しかし、Ｂの焼入れ性向上効果は、ＢがＮ化合物で存在した場合は、無効であるためＢ添加と同時にＮを固定するためにＴｉを添加する。その適正添加量は、Ｎ量により異なるが、０．００５〜０．０５０ｍａｓｓ％の範囲内である。
Ti: 0.005-0.050 mass%, B: 0.0005-0.0100 mass%
B is effective in increasing the hardenability. The effect is obtained at 0.0005 mass% or more, and when it exceeds 0.0100 mass%, the effect is saturated. Therefore, the B content is limited to a range of 0.0005 to 0.0100 mass%. However, the effect of improving the hardenability of B is ineffective when B is an N compound, so Ti is added to fix N simultaneously with the addition of B. The appropriate addition amount varies depending on the N amount, but is in the range of 0.005 to 0.050 mass%.
なお、不可避不純物としてのＰおよび酸素含有量は、できるだけ低い方が望ましい。 The P and oxygen contents as inevitable impurities are preferably as low as possible.
また、被削性を向上させるために必要に応じて、Ｓ、Ｐｂ、Ｓｅ、Ｃａ等の快削元素を含有させても良い。 Moreover, you may contain free-cutting elements, such as S, Pb, Se, and Ca, as needed in order to improve machinability.
表層Ｃ含有量：０．９ｍａｓｓ％未満
浸炭により表層のＣ含有量は高くなる。その結果、表面硬度が上がり、曲げ疲労および面圧疲労強度が向上する。しかし、表層Ｃ含有量が０．９ｍａｓｓ％以上になると、表層付近の粒界にセメンタイトを析出させ、疲労の起点となるために、曲げ疲労強度および面圧疲労強度が低下する。従って、表層Ｃ含有量は、０．９ｍａｓｓ％未満に限定した。
Surface layer C content: less than 0.9 mass% The C content of the surface layer is increased by carburization. As a result, the surface hardness is increased, and bending fatigue and surface fatigue strength are improved. However, if the surface layer C content is 0.9 mass% or more, cementite is precipitated at the grain boundary near the surface layer and becomes a starting point of fatigue, so that the bending fatigue strength and the surface pressure fatigue strength are lowered. Therefore, the surface layer C content is limited to less than 0.9 mass%.
歯面表層の残留オーステナイト量≦４０体積％以下
残留オーステナイトは、それ自体では軟質だが、それが歯面の表層に存在している場合、歯車の駆動中の応力によりマルテンサイトに変態し、硬化するので、曲げおよび面圧疲労に対して亀裂進展を抑制する効果を持つ。しかし、残留オーステナイト量が４０体積％を超えると、逆に表層の硬さの低下が大きくなり過ぎて、曲げ疲労特性および面圧疲労特性は悪くなる。従って、残留オーステナイト量は、４０体積％以下に限定した。
Residual austenite content of the tooth surface surface layer ≦ 40 volume% or less Residual austenite is soft by itself, but when it exists on the surface layer of the tooth surface, it transforms into martensite due to stress during driving of the gear and hardens. Therefore, it has the effect of suppressing crack propagation against bending and surface pressure fatigue. However, when the amount of retained austenite exceeds 40% by volume, the hardness of the surface layer is excessively decreased, and the bending fatigue characteristics and the surface pressure fatigue characteristics are deteriorated. Therefore, the amount of retained austenite is limited to 40% by volume or less.
組織：マルテンサイト単相組織
Ｓｉ、Ｖ等を添加した場合、変態点の上昇により、焼入れ加熱温度でもオーステナイト単相にならず、フェライトが発生する。フェライトは、曲げ疲労破壊での亀裂の進行を早め、疲労強度が低下しやすい。従って、組織は、マルテンサイト単相に限定した。なお、フェライト発生回避については、各種元素の添加量を調整することにより可能である。
Structure: Martensite single phase structure When Si, V, or the like is added, an austenite single phase is not formed even at the quenching heating temperature due to an increase in the transformation point, and ferrite is generated. Ferrite accelerates the progress of cracks due to bending fatigue failure, and fatigue strength tends to decrease. Therefore, the structure was limited to the martensite single phase. It should be noted that the generation of ferrite can be avoided by adjusting the addition amount of various elements.
ショットピーニングのアークハイト：０．３ｍｍＡ以上
ショットピーニングは、表層付近に圧縮残留応力を付与して曲げ疲労強度、面圧疲労強度をさらに上昇させる。この処理を行う場合、アークハイトが０．３ｍｍＡ以下では圧縮残留応力の付与が少なすぎるために曲げ疲労強度、面圧疲労強度をさらに上げることができない。従って、ショットピーニングは、アークハイト０．３ｍｍＡ以上で施すべきである。
Shot peening arc height: 0.3 mmA or more Shot peening imparts compressive residual stress in the vicinity of the surface layer to further increase bending fatigue strength and surface fatigue strength. When this treatment is performed, if the arc height is 0.3 mmA or less, the application of compressive residual stress is too small, so that the bending fatigue strength and the contact pressure fatigue strength cannot be further increased. Therefore, shot peening should be performed at an arc height of 0.3 mmA or more.
この発明を実施例により比較例と対比し、さらに詳細に説明する。 The present invention will be described in more detail in comparison with comparative examples by way of examples.
表１に示す化学成分組成を有する鋼を溶解した。表１に示すＮｏ．１〜１０は、この発明の歯車の製造に用いた本発明鋼であり、Ｎｏ．１１〜１９は、この発明の範囲外である比較鋼である。そして、Ｎｏ．２０、２１は、従来鋼であり、それぞれＪＩＳ ＳＣＭ４２０Ｈ、ＳＣＭ８２２Ｈであり、同じく、この発明の範囲外である。 Steel having the chemical composition shown in Table 1 was melted. No. shown in Table 1. Nos. 1 to 10 are steels of the present invention used for manufacturing the gears of the present invention. 11 to 19 are comparative steels that are outside the scope of the present invention. And No. 20 and 21 are conventional steels, which are JIS SCM420H and SCM822H, respectively, which are also outside the scope of the present invention.
溶製した本発明鋼、比較鋼および従来鋼からなる各インゴットを熱間圧延して丸棒鋼を調製し、得られた丸棒鋼に対し焼準処理を実施して、本発明供試体Ｎｏ．１〜１０、比較供試体Ｎｏ．１１〜１９および従来供試体Ｎｏ．２０、２１を得た。 Each ingot made of the invented steel of the present invention, comparative steel and conventional steel is hot-rolled to prepare a round bar steel, and the obtained round bar steel is subjected to a normalizing treatment. 1-10, comparative specimen No. 11-19 and the conventional specimen No. 20, 21 were obtained.
焼準処理後の各供試体から、２０ｍｍφの各種特性試験用丸棒鋼、小野式回転曲げ疲労試験片およびローラーピッチング試験片を採取した。各種特性試験用丸棒鋼および各試験片に対して、図１に示すパターンに従って浸炭焼入れ・焼戻し処理を施した後、表面にアークハイト０．３ｍｍＡのショットピーニングを施し、各種特性試験、回転曲げ疲労試験およびローラーピッチング試験を実施した。その結果を、粒界酸化層、浸炭部γ粒度および表層Ｃ含有量の結果と併せて表２に示す。 From each specimen after the normalizing treatment, a round bar steel for various characteristic tests of 20 mmφ, an Ono type rotating bending fatigue test piece and a roller pitching test piece were collected. Carved quenching and tempering treatments are performed according to the pattern shown in Fig. 1 on the round bar steel and various test pieces for various characteristic tests, and then the surface is subjected to shot height peening with an arc height of 0.3 mmA to perform various characteristic tests and rotational bending fatigue. Tests and roller pitching tests were performed. The results are shown in Table 2 together with the results of the grain boundary oxide layer, the carburized portion γ grain size, and the surface layer C content.
以下にそれぞれの調査内容について説明する。 The contents of each survey are described below.
(１)有効硬化層深さ、内部の組織、内部靭性、内部硬度
２０ｍｍφの丸棒鋼を切断し、断面の硬度分布を測定し、ビッカース硬さで５５０ＨＶの得られる深さを調査し、有効硬化層深さとした。また、各丸棒鋼の浸炭焼入れ・焼戻しにおける内部（非浸炭部）の組織を検鏡試験で観察し、フェライト析出の有無を確認した。さらに、内部よりＪＩＳ３号衝撃試験片を作製し、２０℃における衝撃値を調査した。内部の硬度については、ビッカース硬度計を用いて測定した。
(1) Effective hardened layer depth, internal structure, internal toughness, internal hardness Cut 20mmφ round bar steel, measure the hardness distribution of the cross section, investigate the depth to obtain 550HV in Vickers hardness, effective hardening It was the depth. Moreover, the inside (non-carburized part) structure in the carburizing and quenching and tempering of each round bar steel was observed with a spectroscopic test to confirm the presence or absence of ferrite precipitation. Furthermore, a JIS No. 3 impact test piece was produced from the inside, and the impact value at 20 ° C. was investigated. The internal hardness was measured using a Vickers hardness tester.
（２）表層残留オーステナイト
別の丸棒鋼を用いて、表層下２０μｍ位置での残留γ量を測定した。なお、測定面の研磨には電解研磨を使用し、測定にはＸ線回折装置を使用した。
(2) Surface layer retained austenite Using another round steel bar, the amount of residual γ at a
（３）回転曲げ疲労特性
直径３２ｍｍの丸棒鋼供試体から、平行部直径１０ｍｍの試験片を採取し、平行部にこれと直角方向の深さ３ｍｍの切り欠き（切り欠き係数：１．４）を全周に亘って付けた回転曲げ疲労試験片を調製した。この試験片全数に対し、浸炭焼入れ・焼戻しを行った。その後、各供試体の試験片について半数にショットピーニング処理（アークハイト：０．３ｍｍＡ）を行った。そして、各試験片のショットピーニング実施品、未実施品について、小野式回転曲げ疲労試験機を使用して１０7回を疲労限度として回転曲げ疲労試験を行い、回転曲げ疲労強度を測定した。
(3) Rotating bending fatigue characteristics A test piece with a parallel part diameter of 10 mm was sampled from a round steel bar with a diameter of 32 mm, and a notch with a depth of 3 mm perpendicular to the parallel part was obtained (notch coefficient: 1.4). Was prepared for a rotating bending fatigue test piece. Carburization quenching and tempering were performed on all the test pieces. Thereafter, half of the test pieces of each specimen were subjected to shot peening treatment (arc height: 0.3 mmA). And about the test peened execution goods of each test piece, and the non-execution goods, the rotation bending fatigue strength was measured by using the Ono-type rotation bending fatigue tester with 10 7 times as a fatigue limit, and the rotation bending fatigue strength was measured.
（４）ローラーピッチング試験（面圧疲労特性）
直径３２ｍｍの丸棒鋼供試体から図２に示す試験面の直径が２６ｍｍ、幅が２８ｍｍの円筒部を有する試験片を作製した。さらに、直径７０ｍｍの丸棒鋼を用いて、鍛造により直径１３５ｍｍとした後、焼準処理を行い、直径１３０ｍｍ、幅１８ｍｍの大ローラーを作製した。次いで、ローラー状試験片および大ローラーの浸炭焼入れ・焼戻し処理を行った。その後、それぞれの半数について回転曲げ疲労試験片と同じ条件でショットピーニング処理（アークハイト：０．３ｍｍＡ）を実施した。そして、各試験片のショットピーニング実施品、未実施品について、ローラーピッチング試験機を使用して１０7回を疲労限度として試験を行った。そのときの試験条件は、回転数：１５００ｒｐｍ、すべり率４０％、潤滑剤：ミッションオイル、油温：１２０℃であった。
(4) Roller pitching test (surface fatigue characteristics)
A test piece having a cylindrical portion having a diameter of 26 mm and a width of 28 mm as shown in FIG. 2 was prepared from a round steel bar having a diameter of 32 mm. Furthermore, after using a round steel bar with a diameter of 70 mm to obtain a diameter of 135 mm by forging, a normalizing process was performed to produce a large roller with a diameter of 130 mm and a width of 18 mm. Next, carburizing and tempering treatment of the roller-shaped test piece and the large roller was performed. Thereafter, a shot peening treatment (arc height: 0.3 mmA) was carried out under the same conditions as for the rotating bending fatigue test piece for each half. Then, the shot peened product and the unexecuted product of each test piece were tested using a roller pitching tester with 10 7 times as the fatigue limit. The test conditions at that time were as follows: rotation speed: 1500 rpm, slip rate of 40%, lubricant: mission oil, oil temperature: 120 ° C.
表１および表２から以下の事項が明らかとなった。 From Table 1 and Table 2, the following matters became clear.
本発明供試体Ｎｏ．１〜１０は、従来供試体Ｎｏ．２０、２１に比べて、内部靭性、浸炭部γ粒度、残留γ量は同等であるものの、粒界酸化層が小さくなっており、そのため、回転曲げ疲労強度が向上した。また、Ｓｉにより焼戻し軟化抵抗が高いために面圧疲労強度が著しく上昇した。 Specimen No. of the present invention. 1 to 10 are conventional specimen Nos. Compared to 20 and 21, the internal toughness, carburized part γ grain size, and residual γ amount were the same, but the grain boundary oxide layer was smaller, and therefore the rotational bending fatigue strength was improved. Moreover, since the temper softening resistance is high due to Si, the surface pressure fatigue strength is remarkably increased.
これに対して、比較供試体Ｎｏ．１１は、Ｃ含有量が本発明範囲より低く、Ｓｉ含有量が本発明の範囲を超えて高いために、内部にフェライトが析出した。そのため内部の硬さが低すぎて、回転曲げ疲労強度が低下した。 In contrast, comparative specimen No. In No. 11, since the C content was lower than the range of the present invention and the Si content exceeded the range of the present invention, ferrite precipitated inside. Therefore, the internal hardness was too low, and the rotational bending fatigue strength was reduced.
比較供試体Ｎｏ．１２は、Ｃ含有量が本発明の範囲を超えており、焼入れ性が高すぎる。そのため内部の靭性が低下した。また、残留γ量が多くなりすぎて浸炭層の硬度が低下し、回転曲げ疲労強度、面圧疲労強度共に低下した。 Comparative specimen No. No. 12, the C content exceeds the range of the present invention, and the hardenability is too high. Therefore, the internal toughness decreased. Further, the amount of residual γ increased too much, and the hardness of the carburized layer decreased, and both the rotary bending fatigue strength and the surface pressure fatigue strength decreased.
比較供試体Ｎｏ．１３は、Ｃｒ含有量が本発明の範囲を超えて高い。そのため内部衝撃値が低くなりすぎたために、回転曲げ疲労強度が低下した。また、Ａｌ含有量が低すぎて、浸炭部γ粒が大きくなっているために面圧疲労強度が低下した。 Comparative specimen No. No. 13 has a high Cr content exceeding the range of the present invention. Therefore, since the internal impact value became too low, the rotational bending fatigue strength decreased. Moreover, since the Al content was too low and the carburized portion γ grains were large, the surface pressure fatigue strength was reduced.
比較供試体Ｎｏ．１４は、Ｍｎ含有量が本発明の範囲より多く、そのために焼入れ性が高すぎた。このために、有効硬化層深さが深くなりすぎて、浸炭層に残留γが多過ぎた。この結果、回転曲げ疲労強度、面圧疲労強度共に低下した。 Comparative specimen No. No. 14 had a Mn content greater than the range of the present invention, and therefore the hardenability was too high. For this reason, the effective hardened layer depth became too deep, and there was too much residual γ in the carburized layer. As a result, both the rotary bending fatigue strength and the contact pressure fatigue strength decreased.
比較供試体Ｎｏ．１５は、Ｍｎ含有量が本発明範囲より低いために、焼入れ性が低すぎて有効硬化層深さが浅すぎ、この結果、マトリックスの強度が不足して、回転曲げ疲労強度が低下した。 Comparative specimen No. In No. 15, since the Mn content was lower than the range of the present invention, the hardenability was too low and the effective hardened layer depth was too shallow. As a result, the strength of the matrix was insufficient and the rotational bending fatigue strength was lowered.
比較供試体Ｎｏ．１６は、Ｃｒ含有量が本発明の範囲より少ないために、焼戻し軟化抵抗が低く、また、焼入れ性が低いために有効硬化層が浅かった。そのため、回転曲げ疲労強度、面圧疲労強度共に低下した。 Comparative specimen No. In No. 16, the Cr content was less than the range of the present invention, so the temper softening resistance was low, and the hardenability was low, so the effective hardened layer was shallow. For this reason, both the rotary bending fatigue strength and the contact pressure fatigue strength decreased.
比較供試体Ｎｏ．１７は、Ｓｉ含有量が本発明の範囲より少ないために、焼戻し軟化抵抗が低く、そのため面圧疲労強度が低下した。 Comparative specimen No. In No. 17, since the Si content was less than the range of the present invention, the temper softening resistance was low, and therefore the surface pressure fatigue strength was reduced.
比較供試体Ｎｏ．１８は、Ｍｏ含有量が本発明範囲よりも低く、そのために焼入れ性が低すぎて内部硬さが低く、有効硬化層深さが浅いために回転曲げ疲労強度が低下した。 Comparative specimen No. In No. 18, the Mo content was lower than the range of the present invention, so that the hardenability was too low, the internal hardness was low, and the effective hardened layer depth was shallow, so the rotational bending fatigue strength was lowered.
比較供試体Ｎｏ．１９は、Ａｌ含有量が本発明範囲よりも高い。そのために結晶粒が大きくなりすぎて、回転曲げ疲労強度、面圧疲労強度共に低下した。 Comparative specimen No. No. 19 has an Al content higher than the range of the present invention. Therefore, the crystal grains became too large, and both the rotational bending fatigue strength and the surface pressure fatigue strength were reduced.
比較供試体Ｎｏ．２０、２１は、従来鋼のＪＩＳ ＳＣＭ４２０Ｈ、ＳＣＭ８２２Ｈであるが、Ｓｉ含有量が本発明の範囲より低く、その結果、粒界酸化層が深くなり、回転曲げ疲労強度、面圧疲労強度共に低下した。 Comparative specimen No. 20 and 21 are JIS SCM420H and SCM822H of conventional steels, but the Si content is lower than the range of the present invention. As a result, the grain boundary oxide layer becomes deep, and both the rotational bending fatigue strength and the surface pressure fatigue strength are reduced. .
Claims (6)
Ｓｉ：０．８〜１．２％、
Ｍｎ：０．６〜２．０％、
Ｓ：０．００６％以上、
Ｃｒ：１．０〜２．０％、
Ｍｏ：０．２〜０．８％、
Ａｌ：０．００５〜０．２００％、
Ｎ：０．００５０〜０．０２００％（以上、ｍａｓｓ％）
を含有し、残部がＦｅおよび不可避的不純物からなる鋼材を、鍛造あるいは機械加工により歯車形状に形成したものからなり、歯車形状に形成後、浸炭処理あるいは浸炭窒化処理を施した時の、表層のＣ含有量が０．９ｍａｓｓ％未満、歯車の表層から１００μｍ深さ位置までの残留オーステナイト量が４０体積％以下、且つ、組織がマルテンサイト単相であることを特徴とする高強度歯車。 C: 0.10 to 0.25%,
Si: 0.8 to 1.2%,
Mn: 0.6 to 2.0%,
S: 0.006% or more,
Cr: 1.0-2.0%,
Mo: 0.2 to 0.8%,
Al: 0.005 to 0.200%,
N: 0.0050-0.0200% (above, mass%)
And the balance of Fe and inevitable impurities is formed into a gear shape by forging or machining, and after forming into a gear shape, carburizing treatment or carbonitriding treatment is performed. A high-strength gear having a C content of less than 0.9 mass%, a retained austenite amount of 40% by volume or less from the gear surface to a depth of 100 μm, and a martensite single phase.
Ｎｂ：０．０１０〜０．０６０％、
Ｖ：０．０５〜０．２０％（以上、ｍａｓｓ％）
の少なくとも１種をさらに含有していることを特徴とする、請求項１記載の高強度歯車。 The steel material is
Nb: 0.010 to 0.060%,
V: 0.05-0.20% (above, mass%)
The high-strength gear according to claim 1, further comprising at least one of the following.
Ｔｉ：０．００５〜０．０５０％、
Ｂ：０．０００５〜０．０１００％（以上、ｍａｓｓ％）
をさらに含有していることを特徴とする、請求項１または２記載の高強度歯車。 The steel material is
Ti: 0.005 to 0.050%,
B: 0.0005 to 0.0100% (above, mass%)
The high-strength gear according to claim 1, further comprising:
Ｓｉ：０．８〜１．２％、
Ｍｎ：０．６〜２．０％、
Ｓ：０．００６％以上、
Ｃｒ：１．０〜２．０％、
Ｍｏ：０．２〜０．８％、
Ａｌ：０．００５〜０．２００％、
Ｎ：０．００５０〜０．０２００％（以上、ｍａｓｓ％）
を含有し、残部がＦｅおよび不可避的不純物からなる鋼材を、鍛造あるいは機械加工により歯車形状に形成して歯車材を調製し、次いで、前記歯車材に浸炭処理あるいは浸炭窒化処理を施し、さらに、アークハイト０．３ｍｍＡ以上のショットピーニングを施して、表層のＣ含有量を０．９ｍａｓｓ％未満、歯車の表層から１００μｍ深さ位置までの残留オーステナイト量を４０体積％以下、且つ、組織をマルテンサイト単相とすることを特徴とする、高強度歯車の製造方法。 C: 0.10 to 0.25%,
Si: 0.8 to 1.2%,
Mn: 0.6 to 2.0%,
S: 0.006% or more,
Cr: 1.0-2.0%,
Mo: 0.2 to 0.8%,
Al: 0.005 to 0.200%,
N: 0.0050-0.0200% (above, mass%)
A steel material containing the balance Fe and inevitable impurities is formed into a gear shape by forging or machining, and then the gear material is subjected to carburizing treatment or carbonitriding treatment, Shot peening with an arc height of 0.3 mmA or more is performed, the C content of the surface layer is less than 0.9 mass%, the amount of retained austenite from the surface layer of the gear to the 100 μm depth position is 40% by volume or less, and the structure is martensite. A method for producing a high-strength gear, characterized by being a single phase.
Ｎｂ：０．０１０〜０．０６０％、
Ｖ：０．０５〜０．２０％（以上、ｍａｓｓ％）
の少なくとも１種をさらに含有したものを使用することを特徴とする、請求項４記載の、高強度歯車の製造方法。 As the steel material,
Nb: 0.010 to 0.060%,
V: 0.05-0.20% (above, mass%)
The method for producing a high-strength gear according to claim 4, wherein a material further containing at least one of the above is used.
Ｔｉ：０．００５〜０．０５０％、
Ｂ：０．０００５〜０．０１００％（以上、ｍａｓｓ％）
をさらに含有するものを使用することを特徴とする、請求項４または５記載の、高強度歯車の製造方法。 As the steel material,
Ti: 0.005 to 0.050%,
B: 0.0005 to 0.0100% (above, mass%)
The method for producing a high-strength gear according to claim 4 or 5, characterized in that a material further containing
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Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
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| JP2008179848A (en) * | 2007-01-24 | 2008-08-07 | Jfe Bars & Shapes Corp | Steel for gear having superior impact fatigue resistance and contact fatigue strength, and gear using the same |
| JP2008261037A (en) * | 2007-04-13 | 2008-10-30 | Sumitomo Metal Ind Ltd | Carburized component or carbonitrided component made of steel and subjected to shot peening |
| WO2009034970A1 (en) * | 2007-09-12 | 2009-03-19 | Sanyo Special Steel Co., Ltd. | Case-hardening steel being excellent in contact pressure fatigue strength, impact strength and bending fatigue strength |
| JP2009068065A (en) * | 2007-09-12 | 2009-04-02 | Sanyo Special Steel Co Ltd | Case hardening steel excellent in bearing fatigue-strength, impact strength and bending fatigue-strength |
| JP2009263767A (en) * | 2008-03-31 | 2009-11-12 | Jfe Steel Corp | Method for manufacturing high-strength case hardened steel part |
| CN104308483A (en) * | 2014-09-05 | 2015-01-28 | 南京金鑫传动设备有限公司 | Method for manufacturing small module gear |
| CN110157864A (en) * | 2019-05-21 | 2019-08-23 | 武汉钢铁有限公司 | A kind of 1300MPa grades of low hydrogen-induced delayed cracking sensibility hot forming steel and production method |
| JP2021095627A (en) * | 2019-12-13 | 2021-06-24 | 愛知製鋼株式会社 | Differential hypoid gear, pinion gear, and paired hypoid gears formed by combination thereof |
| CN114045432A (en) * | 2021-10-30 | 2022-02-15 | 天津荣程联合钢铁集团有限公司 | 22CrMoH hardenability-maintaining gear steel and preparation method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP2008179848A (en) * | 2007-01-24 | 2008-08-07 | Jfe Bars & Shapes Corp | Steel for gear having superior impact fatigue resistance and contact fatigue strength, and gear using the same |
| JP2008261037A (en) * | 2007-04-13 | 2008-10-30 | Sumitomo Metal Ind Ltd | Carburized component or carbonitrided component made of steel and subjected to shot peening |
| WO2009034970A1 (en) * | 2007-09-12 | 2009-03-19 | Sanyo Special Steel Co., Ltd. | Case-hardening steel being excellent in contact pressure fatigue strength, impact strength and bending fatigue strength |
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| JP2021095627A (en) * | 2019-12-13 | 2021-06-24 | 愛知製鋼株式会社 | Differential hypoid gear, pinion gear, and paired hypoid gears formed by combination thereof |
| JP7123098B2 (en) | 2019-12-13 | 2022-08-22 | 愛知製鋼株式会社 | Differential hypoid gears, pinion gears, and hypoid gear pairs that combine these |
| CN114045432A (en) * | 2021-10-30 | 2022-02-15 | 天津荣程联合钢铁集团有限公司 | 22CrMoH hardenability-maintaining gear steel and preparation method thereof |
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