JP2005097682A - Steel, steel sheet and stock belt for continuously variable transmission belt, continuously variable transmission belt, and production method therefor - Google Patents
Steel, steel sheet and stock belt for continuously variable transmission belt, continuously variable transmission belt, and production method therefor Download PDFInfo
- Publication number
- JP2005097682A JP2005097682A JP2003333811A JP2003333811A JP2005097682A JP 2005097682 A JP2005097682 A JP 2005097682A JP 2003333811 A JP2003333811 A JP 2003333811A JP 2003333811 A JP2003333811 A JP 2003333811A JP 2005097682 A JP2005097682 A JP 2005097682A
- Authority
- JP
- Japan
- Prior art keywords
- less
- continuously variable
- steel
- variable transmission
- transmission belt
- 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.)
- Withdrawn
Links
Classifications
-
- Y—GENERAL 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
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Landscapes
- Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
- Heat Treatment Of Articles (AREA)
Abstract
Description
本発明は、溶接によりリング状にしたのちリング圧延して製造される無段変速機ベルト用の鋼，鋼板および素材ベルト並びに無段変速機ベルトおよびその製造法に関する。 The present invention relates to a steel, a steel plate and a material belt for a continuously variable transmission belt manufactured by ring rolling after welding into a ring shape, a continuously variable transmission belt, and a manufacturing method thereof.
従来、無段変速機ベルトに用いる金属リング材としては１８Ｎiマルエージング鋼が使用されてきた。この材料は焼入れ状態でほぼマルテンサイト単相であり、時効処理によって硬度を上昇させ、さらに窒化処理で表面層を硬化させることで素材の耐摩耗性や疲労特性を付与することが可能である。しかし、１８Ｎiマルエージング鋼はＣoを１０％以上含有しているために非常に高価であり、リサイクル性にも問題がある。また、リング溶接時の熱履歴で硬度が上昇するので、そのままリング圧延に供すると板厚制御や周長制御が難しくなる。このため、リング溶接後に焼鈍工程を入れているのが現状であり、工程負荷も大きい。 Conventionally, 18Ni maraging steel has been used as a metal ring material used for a continuously variable transmission belt. This material is substantially martensite single phase in the quenched state, and can increase the hardness by aging treatment and further impart the wear resistance and fatigue characteristics of the material by hardening the surface layer by nitriding treatment. However, 18Ni maraging steel is very expensive because it contains 10% or more of Co, and there is a problem in recyclability. In addition, since the hardness increases due to the heat history during ring welding, it is difficult to control the plate thickness and the circumference when subjected to ring rolling as it is. For this reason, it is the present condition that the annealing process is put after ring welding, and the process load is also large.
下記特許文献１には、１８Ｎiマルエージング鋼よりもさらに疲労特性を向上させた無段変速機ベルト用材料として、準安定オーステナイト系ステンレス鋼を使用したものが記載されている。これは、リング圧延時に加工誘起マルテンサイトを生成させ、さらに時効窒化処理を施すことにより非常に高い疲労特性を実現したものである。 Patent Document 1 listed below uses a metastable austenitic stainless steel as a continuously variable transmission belt material having improved fatigue characteristics as compared with 18Ni maraging steel. This realizes extremely high fatigue properties by generating work-induced martensite during ring rolling and further applying an aging nitriding treatment.
しかしながら、特許文献１の準安定オーステナイト系鋼は、溶体化処理後において基本的にオーステナイト単相組織であるから、十分な量の加工誘起マルテンサイトを確保するためにはリング圧延の工程に大きな負荷がかかる。特に溶接部は歪の少ないオーステナイト単相組織となるため、母材部と溶接部とでほとんど差のない組織状態を得るにはリング圧延での負荷を増大させる必要がある。また、リング圧延後もオーステナイト相が多く存在するので窒化処理には長時間を要する。特許文献１によると時効窒化処理は２０分以上必要であるとされるが、発明者らのその後の調査の結果、２０分程度の短時間では必ずしも安定して窒化が達成ないことがわかった。 However, since the metastable austenitic steel of Patent Document 1 basically has an austenite single-phase structure after solution treatment, a large load is imposed on the ring rolling process in order to ensure a sufficient amount of work-induced martensite. It takes. In particular, since the welded portion has an austenite single-phase structure with little distortion, it is necessary to increase the load in ring rolling in order to obtain a structure state with almost no difference between the base metal part and the welded part. In addition, since many austenite phases exist after ring rolling, a long time is required for the nitriding treatment. According to Patent Document 1, aging nitriding treatment is said to be required for 20 minutes or more. However, as a result of subsequent investigations by the inventors, it has been found that nitriding is not always stably achieved in a short time of about 20 minutes.
一方、昨今では無段変速機の設計技術の進歩等により、特許文献１の材料ほど高い疲労特性を必要としないリング材の用途も増えつつある。特許文献１の材料はコストおよび特性の面で必ずしも合理的とは言えない。 On the other hand, recently, due to advances in design technology for continuously variable transmissions, the use of ring materials that do not require as high fatigue characteristics as the material of Patent Document 1 is increasing. The material of Patent Document 1 is not always reasonable in terms of cost and characteristics.
本発明は、リサイクル性に優れ、リング圧延時に周長制御・板厚制がし易く、かつ、リング圧延や窒化処理の工程負荷を大幅に軽減できる無段変速機ベルト用材料であって、特にコスト・性能バランスに優れたもの、およびそれを用いた無段変速機ベルトを提供することを目的とする。 The present invention is a material for a continuously variable transmission belt that is excellent in recyclability, is easy to control the circumferential length and thickness during ring rolling, and can greatly reduce the process load of ring rolling and nitriding treatment, An object of the present invention is to provide an excellent cost / performance balance and a continuously variable transmission belt using the same.
発明者らの詳細な研究の結果、上記目的は特定組成に調整されたマルテンサイト系ステンレス鋼を使用することにより達成できることがわかった。すなわち、上記目的は、Ｃ：０.１５％以下，Ｓi：２.０％以下，Ｍn：２.０％以下，Ｐ：０.０６０％以下，Ｓ：０.０２０％以下，Ｎi：３.０〜１０.０％，Ｃr：１２.０〜２０.０％，Ｎ：０.１０％以下好ましくは０.０５％以下，Ｍo：４.０％以下，Ｔi：０.７０％以下，Ｏ：０.０２％以下であり、さらに必要に応じてＣu：５.０％以下，Ｎb：０.５０％以下，Ａl：２.０％以下，Ｂ：０.０１５％以下，ＲＥＭ：０.２０％以下，Ｙ：０.２０ ％以下，Ｃa：０.１０％以下，およびＭg：０.１０％以下のうち１種または２種以上を含有し、残部がＦeおよび不可避的不純物からなり、かつ下記(１)式で定義されるＭd(Ｎ)値が１００を超えるように成分調整された無段変速機ベルト用の鋼よって達成される。
Ｍd(Ｎ)＝５８０−５２０Ｃ−２Ｓi−１６Ｍn−１６Ｃr−２３Ｎi−２６Ｃu−３００Ｎ−１０Ｍo ……(１)
ここで、(１)式の元素記号の箇所には質量％で表された当該元素の含有量が代入される。
As a result of detailed studies by the inventors, it has been found that the above object can be achieved by using a martensitic stainless steel adjusted to a specific composition. That is, the objectives are as follows: C: 0.15% or less, Si: 2.0% or less, Mn: 2.0% or less, P: 0.060% or less, S: 0.020% or less, Ni: 3. 0 to 10.0%, Cr: 12.0 to 20.0%, N: 0.10% or less, preferably 0.05% or less, Mo: 4.0% or less, Ti: 0.70% or less, O : 0.02% or less, and if necessary, Cu: 5.0% or less, Nb: 0.50% or less, Al: 2.0% or less, B: 0.015% or less, REM: 0.00 20% or less, Y: 0.20% or less, Ca: 0.10% or less, and Mg: 0.10% or less, and the balance consists of Fe and inevitable impurities, And it is achieved by the steel for continuously variable transmission belts whose components are adjusted so that the Md (N) value defined by the following formula (1) exceeds 100.
Md (N) = 580-520C-2Si-16Mn-16Cr-23Ni-26Cu-300N-10Mo (1)
Here, the content of the element represented by mass% is substituted for the element symbol in the formula (1).
また、前記の鋼からなる鋼板を溶体化処理することにより６０体積％以上のマルテンサイトを生成させた鋼板であって、溶接によりリング状にしてリング圧延に供するための鋼板が提供される。
ここで、リング圧延とは、リング状の無端金属ベルトを２個のドラムあるいはプーリーに架けて張力を付与した状態で回動させながら圧延ロールで冷間圧延する圧延方法である。
Moreover, the steel plate which produced | generated the martensite of 60 volume% or more by solution-treating the steel plate which consists of said steel, Comprising: The steel plate for making it ring-shaped by welding and using for ring rolling is provided.
Here, the ring rolling is a rolling method in which a ring-shaped endless metal belt is cold-rolled with a rolling roll while being rotated with two tensions applied to two drums or pulleys.
無段変速機ベルトを製造するための中間製品として、前記の鋼からなる溶体化処理後の鋼板を溶接してリング状にしたのちリング圧延することにより、溶接部および母材部とも８０積％を超えるマルテンサイト（加工誘起マルテンサイトを含む）を有する組織とした素材ベルトであって、後工程で表面を窒化して無段変速機ベルトを得るための素材ベルトが提供される。
素材ベルトは圧延されているので、リング圧延前の溶接部は圧延方向に引き延ばされている。したがって、ここでいう「溶接部」とはリング圧延前の溶接部に由来する部分を意味する。同様に、ここでいう「母材部」とはリング圧延前の母材部（溶接部以外の部分）に由来する部分を意味する。
As an intermediate product for manufacturing a continuously variable transmission belt, the steel plate after solution treatment made of the above steel is welded into a ring shape and then ring-rolled, so that both the welded portion and the base material portion are 80% by volume. There is provided a material belt having a structure having a martensite exceeding (including processing-induced martensite), for obtaining a continuously variable transmission belt by nitriding the surface in a subsequent process.
Since the material belt is rolled, the welded portion before ring rolling is stretched in the rolling direction. Therefore, the “welded part” here means a part derived from the welded part before ring rolling. Similarly, the “base material part” here means a part derived from the base material part (part other than the welded part) before ring rolling.
最終的な無段変速機ベルトとして、前記の鋼からなる溶体化処理後の鋼板を溶接してリング状にしたのちリング圧延し、その後の工程で表面を窒化して得られた無段変速機ベルトであって、鋼素地は溶接部および母材部とも８０体積％を超えるマルテンサイト（加工誘起マルテンサイトを含む）を有する組織を呈し、表層部が窒化層で覆われた無段変速機ベルトが提供される。なかでも、板厚０.０３〜０.５ｍｍ，幅３〜５０ｍｍであり、引張強さが１３００Ｎ／ｍｍ2以上，疲労限界応力が６００Ｎ／ｍｍ2以上である無段変速機ベルトが提供される。
ここで鋼素地とは、表層の窒化層を除くマトリクスをいう。
As a final continuously variable transmission belt, a continuously variable transmission obtained by welding and rolling the steel plate after solution treatment made of the steel described above, then rolling and nitriding the surface in the subsequent process A continuously variable transmission belt in which a steel base exhibits a structure having martensite (including processing-induced martensite) exceeding 80% by volume in both a welded portion and a base material portion, and a surface layer portion is covered with a nitride layer. Is provided. Among them, a thickness 0.03 to 0.5 mm, a width of 3 to 50 mm, a tensile strength of 1300 N / mm 2 or more, the continuously variable transmission belt is provided fatigue limit stress is 600N / mm 2 or more .
Here, the steel substrate refers to a matrix excluding the nitrided surface layer.
また本発明では、無段変速機ベルトの製造法として、前記の鋼からなる溶体化処理後の鋼板を溶接してリング状にしたのち、圧延率３〜６０％のリング圧延を施し、必要に応じてバレル研摩，ショットピーニング処理およびショットブラスト処理のうち１種または２種以上を施し、その後、３００〜６００℃の窒化環境下に１〜２０分間曝すことにより時効処理および窒化処理を同時に行う無段変速機ベルトの製造法が提供される。 Moreover, in this invention, as a manufacturing method of a continuously variable transmission belt, after welding the steel plate after solution treatment which consists of said steel and making it ring shape, ring rolling with a rolling rate of 3 to 60% is given, and it is required In accordance with barrel polishing, shot peening treatment and shot blasting treatment, one or more kinds are applied, and then aging treatment and nitriding treatment are performed simultaneously by exposure to a nitriding environment at 300 to 600 ° C. for 1 to 20 minutes. A method of manufacturing a step transmission belt is provided.
特にその窒化環境が、アンモニアガスを主成分（少なくとも４０体積％以上含有）とするガスである製造法、および、ＮaＣＮ，ＫＣＮ，ＮaＣＮＯおよびＫＣＮＯの１種または２種以上を基本成分（少なくとも４０質量％以上含有）とし、これにＮa2ＣＯ3およびＫ2ＣＯ3の１種または２種を添加した溶融塩である製造法が提供される。 In particular, the production method in which the nitriding environment is a gas containing ammonia gas as a main component (containing at least 40% by volume or more), and one or more of NaCN, KCN, NaCNO and KCNO as basic components (at least 40 mass) And a production method of a molten salt obtained by adding one or two of Na 2 CO 3 and K 2 CO 3 thereto.
本発明ではマルテンサイト系ステンレス鋼を用いたことにより、従来の１８Ｎiマルエージング鋼に比べリサイクル性に優れ、リング圧延時に周長制御・板厚制がし易いというメリットがある。また、準安定オーステナイト系ステンレス鋼を用いた場合に比べ、リング圧延や窒化処理の工程負荷を大幅に軽減でき、かつ、溶接部と母材部で特性にほとんど差のない無段変速機ベルトが容易に製造できるというメリットがある。特に本発明によれば、コストと性能のバランスに優れた無段変速機ベルトが提供できる。したがって本発明は、コスト面がマイナス要因となっている無段変速機の普及に寄与しうるものである。 In the present invention, the use of martensitic stainless steel is advantageous in that it is more recyclable than conventional 18Ni maraging steel, and it is easy to control the circumference and plate thickness during ring rolling. Compared to the case of using metastable austenitic stainless steel, the process load of ring rolling and nitriding treatment can be greatly reduced, and a continuously variable transmission belt with almost no difference in characteristics between the welded part and the base metal part. There is an advantage that it can be easily manufactured. In particular, according to the present invention, a continuously variable transmission belt excellent in balance between cost and performance can be provided. Therefore, the present invention can contribute to the spread of continuously variable transmissions whose cost is a negative factor.
発明者らの詳細な検討の結果、コストと性能のバランスに優れた無段変速機ベルトはマルテンサイト系ステンレス鋼を使用することによって達成可能であることが明らかになった。ただし、単に鋼種をマルテンサイト系にするだけで無段変速機ベルトにそのまま使用できるわけではない。それには、化学組成の厳密な調整と、適切な製造工程が必要となる。以下、本発明を特定するための事項について説明する。 As a result of detailed studies by the inventors, it has been clarified that a continuously variable transmission belt excellent in balance between cost and performance can be achieved by using martensitic stainless steel. However, it is not possible to use the steel grade as it is for a continuously variable transmission belt simply by making the steel type martensitic. This requires precise adjustment of the chemical composition and appropriate manufacturing processes. Hereinafter, matters for specifying the present invention will be described.
Ｃは、オーステナイト形成元素であり、高温で生成するδフェライト相の抑制やマルテンサイト相の強化に極めて有効である。しかし、Ｃ含有量の増加に伴い、溶体化処理後の冷却中や時効処理時に粒界に析出するＣr炭化物が増加し、耐粒界腐食性や疲労特性の低下要因となる。これは熱処理条件等の最適化によりある程度回避できるが、工業的な限界を考慮すると、Ｃ含有量の上限は０.１５質量％に制限される。Ｃ含有量の下限は、溶体化処理後に概ね６０体積％以上のマルテンサイト量が確保できる限り特に制限されないが、０.００５質量％以上のＣ含有が望ましい。 C is an austenite-forming element and is extremely effective in suppressing the δ ferrite phase generated at high temperatures and strengthening the martensite phase. However, with an increase in the C content, Cr carbide precipitated at the grain boundaries during cooling after the solution treatment or during aging treatment increases, which causes a decrease in intergranular corrosion resistance and fatigue characteristics. This can be avoided to some extent by optimizing the heat treatment conditions and the like, but considering the industrial limit, the upper limit of the C content is limited to 0.15% by mass. The lower limit of the C content is not particularly limited as long as a martensite amount of approximately 60% by volume or more can be secured after the solution treatment, but 0.005% by mass or more of C content is desirable.
Ｓiは、マルテンサイト相を固溶強化し、特にリング圧延後の高強度化に寄与する。歪時効により時効硬化能を向上させる効果もある。しかし過度の添加は高温割れを誘発し易く、製造上の問題を生じる。このためＳi含有量は２.０質量％以下に限される。 Si strengthens the martensite phase by solid solution, and contributes to increasing the strength particularly after ring rolling. There is also an effect of improving age hardening ability by strain aging. However, excessive addition tends to induce hot cracking and causes manufacturing problems. For this reason, Si content is limited to 2.0 mass% or less.
Ｍnは、高温域でのδフェライト相の生成を抑制する。しかし、多量の添加は溶体化処理後の残留オーステナイト量を多くし、強度低下の要因となる。このためＭn含有量は２.０質量％以下に制限される。 Mn suppresses the formation of the δ ferrite phase in the high temperature range. However, a large amount of addition increases the amount of retained austenite after the solution treatment, which causes a decrease in strength. For this reason, Mn content is restrict | limited to 2.0 mass% or less.
Ｐは、固溶強化能が大きい元素であるが、靱性に悪影響を与えることがあるために０.０６０質量％以下に制限される。
Ｓは、熱間圧延での耳切れ発生の面から好ましくない元素であり、０.０２０質量％以下に制限される。
P is an element having a large solid solution strengthening ability, but is limited to 0.060% by mass or less because it may adversely affect toughness.
S is an element that is not preferable from the viewpoint of occurrence of edge breakage in hot rolling, and is limited to 0.020% by mass or less.
Ｎiは、Ｍnと同様にδフェライト相の生成を抑制する。また、時効硬化に寄与する。これらの効果を十分に発揮させるには３.０質量％以上のＮiが必要である。しかし、多量のＮi含有は溶体化処理後の残留オーステナイト量を増加させ、強度低下の要因となる。このためＮi含有量は３.０〜１０.０質量％の範囲に限定される。 Ni, like Mn, suppresses the formation of the δ ferrite phase. It also contributes to age hardening. To sufficiently exhibit these effects, 3.0% by mass or more of Ni is necessary. However, a large amount of Ni contained increases the amount of retained austenite after the solution treatment, which causes a decrease in strength. For this reason, Ni content is limited to the range of 3.0-10.0 mass%.
Ｎは、Ｃと同様にオーステナイト形成元素であり、δフェライト生成を抑制し、マルテンサイト相の強化に寄与する。ただし、Ｔiとの非金属介在物を生成し易いので、０.１０質量％以下に制限される。０.０５質量％以下とすることが一層好ましい。 N, like C, is an austenite-forming element, suppresses the formation of δ ferrite, and contributes to the strengthening of the martensite phase. However, since it is easy to produce non-metallic inclusions with Ti, it is limited to 0.10% by mass or less. More preferably, it is 0.05 mass% or less.
Ｍoは、ステンレス鋼の耐食性を向上させ、また、時効処理時に炭化物を微細に分散させる効果がある。さらにＭoには、高温で時効した場合に歪の急激な解放を抑制する効果があり、時効温度の高温・短時間化に寄与し得る。ただし、後述のように窒化処理と時効処理を同時に行う場合には窒化によって熱処理時間が律速されるため、本発明では特にＭoを添加しなくてもよい。一方、Ｍoを多量に添加するとδフェライトが生成し易くなるので、Ｍoを添加する場合は４.０質量％以下の範囲で行うことが望ましい。特に好ましいＭoの含有量範囲は０.５〜２.５質量％である。 Mo improves the corrosion resistance of stainless steel and has the effect of finely dispersing carbides during aging treatment. Furthermore, Mo has an effect of suppressing rapid release of strain when aged at a high temperature, and can contribute to a high aging temperature and a short time. However, when the nitriding treatment and the aging treatment are performed simultaneously as will be described later, the heat treatment time is limited by nitriding, and therefore Mo is not particularly required in the present invention. On the other hand, when a large amount of Mo is added, δ ferrite is likely to be formed. Therefore, when Mo is added, it is preferable to perform the addition in a range of 4.0% by mass or less. A particularly preferable Mo content range is 0.5 to 2.5% by mass.
Ｔiは、析出硬化作用を呈し、強度向上に寄与する。ただし、０.７０質量％を超えると製鋼スラブの表面疵が発生し易くなり、製造面での問題が顕在化する。このためＴi含有量の上限は０.７０質量％に制限される。なお、Ｔiは０.１０質量％以上添加することが好ましい。 Ti exhibits precipitation hardening action and contributes to strength improvement. However, if it exceeds 0.70% by mass, surface flaws of the steelmaking slab are likely to occur, and problems on the manufacturing surface become obvious. For this reason, the upper limit of Ti content is limited to 0.70 mass%. Ti is preferably added in an amount of 0.10% by mass or more.
Ｏは、酸化物系の非金属介在物を形成して鋼の清浄度を低下させるため、０.０２質量％以下に制限される。 O is limited to 0.02% by mass or less because it forms oxide-based nonmetallic inclusions and lowers the cleanliness of the steel.
Ｂは、熱間圧延温度域でのδフェライト相とオーステナイト相の変形抵抗の差に起因した熱間加工性の低下を改善する作用があり、特に熱延耳切れの防止に有効である。しかし、過度の添加は低融点硼化物の形成を招き、逆に熱間加工性を劣化させる。このため、Ｂを添加する場合は０.０１５質量％以下の範囲で行う必要がある。なお、Ｂは０.００１質量％以上添加することが特に好ましい。 B has the effect of improving the decrease in hot workability due to the difference in deformation resistance between the δ ferrite phase and the austenite phase in the hot rolling temperature range, and is particularly effective in preventing hot-earing breakage. However, excessive addition leads to the formation of a low-melting boride and conversely deteriorates hot workability. For this reason, when adding B, it is necessary to carry out in the range of 0.015 mass% or less. B is particularly preferably added in an amount of 0.001% by mass or more.
Ｃuは、時効硬化に寄与する。ただし、過剰の添加は熱間加工性の低下を招くので、Ｃuを添加する場合は５.０質量％以下の範囲で行う必要がある。なお、Ｃuは０.５質量％以上添加することが特に好ましい。 Cu contributes to age hardening. However, excessive addition causes a decrease in hot workability. Therefore, when Cu is added, it is necessary to add it in a range of 5.0% by mass or less. Cu is particularly preferably added in an amount of 0.5% by mass or more.
Ｎbは、時効処理時の強度向上に有効であるが、高温強度上昇による熱間加工性の低下を招くので、Ｎbを添加する場合は０．５0質量％以下の範囲で行う。なお、Ｎbは０.０５質量％以上添加することが特に好ましい。 Nb is effective in improving the strength at the time of aging treatment, but causes a decrease in hot workability due to an increase in high-temperature strength. Therefore, when Nb is added, it is performed in a range of 0.50% by mass or less. Nb is particularly preferably added in an amount of 0.05% by mass or more.
Ａlは、製鋼時の脱酸に有効であるとともに、ＴiやＮｂと同様に析出硬化に寄与する。しかし、２.０質量％を超えて添加してもこれらの効果は飽和し、逆に溶接性の低下や表面欠陥の増加といった弊害を招く。したがって、Ａlを添加する場合は２.０質量％以下の範囲で行う。なお、Ａlは０.０１質量％以上含有させることが特に好ましい。 Al is effective for deoxidation during steel making and contributes to precipitation hardening in the same manner as Ti and Nb. However, even if added in excess of 2.0% by mass, these effects are saturated, and conversely, adverse effects such as a decrease in weldability and an increase in surface defects are caused. Therefore, when adding Al, it is carried out in a range of 2.0% by mass or less. Al is particularly preferably contained in an amount of 0.01% by mass or more.
ＲＥＭ（希土類元素），Ｙ，ＣaおよびＭgは熱間加工性の向上に有効な元素であり、耐酸化性の向上にも有効である。これらの１種または２種以上の元素を添加する場合は、ＲＥＭ，Ｙについてはそれぞれ０.２０質量％以下、Ｃa，Ｍgについてはそれぞれ０.１０質量％以下の範囲で行うことが適切である。なお、ＲＥＭは０.００１質量％以上、Ｙは０.００３質量％以上、Ｃaは０.００１質量％以上、Ｍgは０.００５質量％以上添加することが特に効果的である。 REM (rare earth element), Y, Ca, and Mg are effective elements for improving hot workability and also effective for improving oxidation resistance. When one or more of these elements are added, it is appropriate that REM and Y are each within a range of 0.20% by mass or less, and Ca and Mg are each within a range of 0.10% by mass or less. . Note that it is particularly effective to add 0.001% by mass or more of REM, 0.003% by mass or more of Y, 0.001% by mass or more of Ca, and 0.005% by mass or more of Mg.
以上の含有量範囲において、さらに下記(１)式で定義されるＭd(Ｎ)値が１００を超えるように各元素の含有量を調整する。
Ｍd(Ｎ)＝５８０−５２０Ｃ−２Ｓi−１６Ｍn−１６Ｃr−２３Ｎi−２６Ｃu−３００Ｎ−１０Ｍo ……(１)
In the content range described above, the content of each element is adjusted so that the Md (N) value defined by the following formula (1) exceeds 100.
Md (N) = 580-520C-2Si-16Mn-16Cr-23Ni-26Cu-300N-10Mo (1)
従来、Ｍd(Ｎ)値が１００を超えると加工誘起マルテンサイトの生成が活発になりすぎ、疲労特性の向上には逆効果であると考えられていた。しかし発明者らの最近の研究の結果、Ｍd(Ｎ)値が１００を超える領域でも無段変速機ベルトとして十分使用できる特性が付与できることが明らかになった。むしろ、Ｍd(Ｎ)値を１００を超える値に調整することによって、リング圧延の負荷を軽減することができ、かつ、窒化処理の時間も短縮することができるという大きなコストメリットが得られる。このため、本発明では鋼の化学組成をＭd(Ｎ)値が１００を超えるように調整する。 Conventionally, when the Md (N) value exceeds 100, the production of work-induced martensite becomes too active, and it has been considered to be counterproductive to improving fatigue properties. However, as a result of recent studies by the inventors, it has become clear that characteristics that can be sufficiently used as a continuously variable transmission belt can be imparted even in a region where the Md (N) value exceeds 100. Rather, by adjusting the Md (N) value to a value exceeding 100, a great cost merit is obtained that the load of ring rolling can be reduced and the nitriding time can be shortened. Therefore, in the present invention, the chemical composition of the steel is adjusted so that the Md (N) value exceeds 100.
以上の化学組成を有するマルテンサイト系ステンレス鋼を熱間圧延あるいはさらに冷間圧延して、リング圧延に供するために適切な板厚の鋼板とする。これに溶体化処理を施し、６０体積％以上のマルテンサイト相を有する鋼板を得る。この段階でマルテンサイト量が６０体積％未満だとリング圧延で生成させるべき加工誘起マルテンサイトの量が多くなり、リング圧延の負荷が大きくなって好ましくない。溶体化処理は、９５０〜１１００℃の範囲で均熱０〜１０分加熱後、水冷または空冷する条件で行うことができる。通常、溶体化処理後に酸洗を行う。 The martensitic stainless steel having the above chemical composition is hot-rolled or further cold-rolled to obtain a steel plate having an appropriate thickness for use in ring rolling. This is subjected to a solution treatment to obtain a steel sheet having a martensite phase of 60% by volume or more. If the amount of martensite is less than 60% by volume at this stage, the amount of work-induced martensite to be generated by ring rolling increases, and the load of ring rolling increases, which is not preferable. The solution treatment can be performed under conditions of water cooling or air cooling after heating in a range of 950 to 1100 ° C. for 0 to 10 minutes. Usually, pickling is performed after the solution treatment.
溶体化処理後の前記鋼板を所定の長さおよび幅のバンドにカットし、このバンドの端部どうしを溶接により接合して無端金属ベルトを得る。この無端金属ベルトを２個のドラムあるいはプーリーに架けて張力を付与した状態で回動させながらリング圧延を行う。無段変速機ベルト所定の長さ・板厚になるまでリング圧延を行う。その際、リング圧延後に溶接部および母材部とも８０体積％を超えるマルテンサイト（加工誘起マルテンサイトを含む）を有する組織状態とすることが重要である。実質的に１００％マルテンサイト組織となってもよい。マルテンサイト量がこれより少ないと十分な強度および疲労特性を付与することが難しい。また、後工程の窒化処理に長時間を要する。 The steel plate after the solution treatment is cut into a band having a predetermined length and width, and ends of the band are joined together by welding to obtain an endless metal belt. Ring rolling is performed while the endless metal belt is rotated on two drums or pulleys while being rotated. Ring rolling is performed until the continuously variable transmission belt reaches a predetermined length and thickness. At that time, it is important that the welded portion and the base metal portion have a martensite (including work-induced martensite) exceeding 80% by volume after ring rolling. A substantially 100% martensite structure may be formed. If the amount of martensite is less than this, it is difficult to impart sufficient strength and fatigue characteristics. Further, a long time is required for the nitriding process in the subsequent process.
リング圧延に供する無端金属ベルトの初期周長および板厚を、その鋼（化学組成）に必要な圧延率に基づいて適切にコントロールすることが必要である。リング圧延率は３〜６０％の範囲で設定することが好ましい。前記の化学組成範囲であれば、この圧延率範囲において溶接部および母材部とも８０体積％を超えるマルテンサイトを有する組織とすることが可能であり、ベルト全周においてほぼ均一な特性が得られる。リング圧延を終えた段階のこのベルト（中間製品）を本発明では「素材ベルト」と呼んでいる。 It is necessary to appropriately control the initial circumferential length and thickness of an endless metal belt subjected to ring rolling based on the rolling rate required for the steel (chemical composition). The ring rolling rate is preferably set in the range of 3 to 60%. Within the above-described chemical composition range, it is possible to obtain a structure having martensite exceeding 80 volume% in both the welded portion and the base metal portion in this rolling rate range, and substantially uniform characteristics can be obtained over the entire belt circumference. . In the present invention, this belt (intermediate product) at the stage where ring rolling has been completed is called a “material belt”.
この素材ベルトに、必要に応じてバレル研摩，ショットピーニング処理またはショットブラスト処理を施す。これらのうち１種のみを施してもよいし、２種以上を順次施す「複合処理」としてもよい。これらの処理により素材ベルト表面に圧縮応力が付与され、疲労特性の向上に有効となる。 This material belt is subjected to barrel polishing, shot peening or shot blasting as necessary. Of these, only one type may be applied, or “composite processing” in which two or more types are sequentially applied may be used. By these treatments, compressive stress is applied to the material belt surface, which is effective in improving fatigue characteristics.
次いで、時効処理と窒化処理を兼ねた時効窒化処理を行う。前記素材ベルトまたは前記バレル研摩等を施したベルトを３００〜６００℃の窒化環境下に１〜２０分間曝すことによって時効窒化処理が達成できる。前述のように、リング圧延後には８０体積％を超えるマルテンサイト相を有する組織に調整されているので、２０分以下の短時間で窒化を終了することができる。１５分以下の短時間処理とすることが一層好ましい。同時に、時効処理も達成され、強度および疲労特性が一層向上する。 Next, an aging nitriding treatment that combines an aging treatment and a nitriding treatment is performed. An aging nitriding treatment can be achieved by exposing the material belt or the barrel-polished belt to a nitriding environment at 300 to 600 ° C. for 1 to 20 minutes. As described above, since the structure is adjusted to a structure having a martensite phase exceeding 80 volume% after ring rolling, nitriding can be completed in a short time of 20 minutes or less. More preferably, the treatment is performed for a short time of 15 minutes or less. At the same time, an aging treatment is also achieved, and the strength and fatigue properties are further improved.
窒化環境としては、ガス窒化法，塩浴窒化法，ガス浸硫窒化法，プラズマ窒化法等の環境が使用できる。 As the nitriding environment, an environment such as a gas nitriding method, a salt bath nitriding method, a gas immersion nitriding method, or a plasma nitriding method can be used.
ガス窒化法の場合は、アンモニアガスを主成分とするガス環境が使用できる。例えば、アンモニアガスに、ＲＸガス（吸熱型変成ガス；ＣＯ＋Ｈ2＋Ｎ2），プロパンガス，ブタンガス，（ＣＯ2＋ＣＯ）混合ガス等を混合した雰囲気を採用することが好適である。 In the case of the gas nitriding method, a gas environment mainly containing ammonia gas can be used. For example, it is preferable to employ an atmosphere obtained by mixing ammonia gas with RX gas (endothermic modified gas; CO + H 2 + N 2 ), propane gas, butane gas, (CO 2 + CO) mixed gas, or the like.
塩浴窒化法の場合は、例えば、ＮaＣＮ，ＫＣＮ，ＮaＣＮＯおよびＫＣＮＯの１種または２種以上を少なくとも合計４０質量％以上含有し、これにＮa2ＣＯ3およびＫ2ＣＯ3の１種または２種を添加した溶融塩に浸漬する方法が好適である。 In the case of the salt bath nitriding method, for example, one or two of NaCN, KCN, NaCNO and KCNO are contained in a total of at least 40% by mass, and one or two of Na 2 CO 3 and K 2 CO 3 are contained therein. A method of immersing in a molten salt to which a seed is added is preferable.
このようにして得られた無端金属ベルトは、鋼素地が溶接部および母材部とも８０体積％を超えるマルテンサイト（加工誘起マルテンサイトを含む）を有する組織を呈し、表層部が窒化層で覆われたものであり、無段変速機ベルトとして使用できる優れた特性を有する。なかでも、板厚０.０３〜０.５ｍｍ，幅３〜５０ｍｍであり、引張強さが１３００Ｎ／ｍｍ2以上，疲労限界応力が６００Ｎ／ｍｍ2以上の合理的な特性を呈する無段変速機ベルトがコスト−性能バランスに優れたものとして提供できる。 The endless metal belt thus obtained has a structure in which the steel base has martensite (including work-induced martensite) exceeding 80% by volume in both the welded portion and the base metal portion, and the surface layer portion is covered with a nitride layer. It has excellent characteristics that can be used as a continuously variable transmission belt. Among them, a thickness 0.03 to 0.5 mm, a width of 3 to 50 mm, a tensile strength of 1300 N / mm 2 or more, CVT fatigue limit stress exhibits 600N / mm 2 or more reasonable properties The belt can be provided with an excellent cost-performance balance.
表１に供試材の化学組成を示す。鋼１〜鋼７が本発明対象鋼、鋼８〜１３が比較鋼である。 Table 1 shows the chemical composition of the test materials. Steels 1 to 7 are steels according to the present invention, and steels 8 to 13 are comparative steels.
いずれの鋼も真空溶解炉で溶製し、鍛造、熱延、中間焼鈍、冷延を行い、１０５０℃で１分間保持したのち水冷する溶体化処理を施して無端金属ベルトにするための素材鋼板を得た。各鋼板から幅２０ｍｍのベルトを切り出し、長手方向の両端部をＴＩＧ溶接にて接合して無端金属ベルトとした。これを圧延率６〜５４％の範囲で板厚０.１８ｍｍまでリング圧延を行った。リング圧延後の素材ベルトにバレル研磨，ショットブラスト処理およびショットピーニング処理の１種または２種以上の機械的表面処理を施し、その後、５０体積％アンモニアガス＋５０体積％ＮＸガスからなる種々の温度の混合ガス中で１５分間加熱して時効処理と窒化処理を同時に行った（時効窒化処理）。 Each steel is melted in a vacuum melting furnace, forged, hot-rolled, intermediate-annealed, cold-rolled, held at 1050 ° C for 1 minute, and then subjected to a solution treatment that is water-cooled to form an endless metal belt Got. A belt having a width of 20 mm was cut out from each steel plate, and both end portions in the longitudinal direction were joined by TIG welding to form an endless metal belt. This was subjected to ring rolling to a sheet thickness of 0.18 mm within a rolling rate of 6 to 54%. The material belt after the ring rolling is subjected to one or more mechanical surface treatments such as barrel polishing, shot blasting and shot peening, and then at various temperatures composed of 50% by volume ammonia gas + 50% by volume NX gas. An aging treatment and a nitriding treatment were simultaneously performed by heating in a mixed gas for 15 minutes (aging nitriding treatment).
溶体化処理後の鋼板および、時効窒化処理後の無端ベルトについて、板断面の光学顕微鏡観察によりマルテンサイト量（時効処理後のものについては加工誘起マルテンサイトを含む）を測定した。なお、時効窒化処理の前後でマルテンサイト量はほとんど変化しないことを確かめている。 With respect to the steel plate after solution treatment and the endless belt after aging nitriding treatment, the amount of martensite (including work-induced martensite in the case of aging treatment) was measured by optical microscope observation of the plate cross section. It has been confirmed that the amount of martensite hardly changes before and after the aging nitriding treatment.
また、時効窒化処理後の無端ベルトから試験片を切り出して、引張強さおよび疲労限を測定した。
引張試験は、ＪＩＳ Ｚ ２２０１に規定の１３Ｂ号試験片を用い、ＪＩＳ Ｚ ２２４１に準じて行った。
疲労限は、長さ１００ｍｍ，幅８ｍｍの平行部を有する試験片を用いて、回転数６００ｒｐｍ，応力比（最大応力／最小応力）；−１の条件で両振り曲げ疲労試験を行って求めた。１×１０7サイクルで破断しない最大応力を疲労限とした。
結果を表２に示す。
Moreover, a test piece was cut out from the endless belt after the aging nitriding treatment, and the tensile strength and the fatigue limit were measured.
The tensile test was performed according to JIS Z 2241 using a 13B test piece defined in JIS Z 2201.
The fatigue limit was obtained by performing a double-bending bending fatigue test using a test piece having a parallel portion of 100 mm in length and 8 mm in width under the conditions of a rotation speed of 600 rpm and a stress ratio (maximum stress / minimum stress); . The maximum stress that did not break in 1 × 10 7 cycles was defined as the fatigue limit.
The results are shown in Table 2.
本発明例であるＮｏ.１〜１０は、リング圧延率６０％以下，時効窒化処理１５分という工程負荷の少ない手法にて、引張強さ１３００Ｎ／ｍｍ2以上，疲労限６００Ｎ／ｍｍ2以上のＣＶＴベルト用金属リングに適したものが得られた。 The present invention is an example No.1~10, the ring rolling of 60% or less, with a small approach the process load of aging nitriding 15 minutes, tensile strength 1300 N / mm 2 or more, fatigue limit 600N / mm 2 or more What was suitable for the metal ring for CVT belts was obtained.
これに対し、比較例であるＮｏ.１１および１３は本発明規定の化学組成を有する鋼（発明対象鋼）を用いたが、時効窒化処理温度が高すぎたため引張強さ，疲労限とも低かった。Ｎｏ.１２も発明対象鋼であるが、時効窒化処理温度が低すぎたため疲労限に劣った。Ｎｏ.１４および１５はＮi含有量が低すぎたため時効硬化能が小さく、引張強さおよび疲労限が低かった。また、Ｎｏ.１４の場合、Ａl含有量が高すぎたためＡlＮが多量に生成したことも特性低下に影響した。Ｎｏ.１６はＮ含有量が比較的高いためにＴiＮの生成が比較的多く、また、Ｍd(Ｎ)が低すぎたためにマルテンサイト量が８０体積％に達せず、結果的に疲労限が低かった。Ｎｏ.１７はＴi含有量が高すぎたため多量のＴiＮが生成し、疲労限が低かった。Ｎｏ.１８はＭd(Ｎ)が低すぎたためにマルテンサイト量が８０体積％に達せず、疲労限が低かった。Ｎｏ.１９はＣ含有量が高すぎたため炭化物析出量が多くなり、疲労限が低かった。なお、Ｎｏ.１７はＴiＮ起因の表面疵が多発し、Ｎｏ.１９は鋭敏化による発銹が問題となった。 On the other hand, Nos. 11 and 13 as comparative examples used steel having the chemical composition defined in the present invention (invention target steel), but because the aging nitriding temperature was too high, the tensile strength and fatigue limit were both low. . No. 12 is also a steel subject to invention, but its fatigue limit was inferior because the aging nitriding temperature was too low. Nos. 14 and 15 had a low age-hardening ability because the Ni content was too low, and the tensile strength and fatigue limit were low. Further, in the case of No. 14, since the Al content was too high, a large amount of AlN was produced, which also affected the characteristic deterioration. In No. 16, since the N content is relatively high, the production of TiN is relatively large, and since Md (N) is too low, the martensite amount does not reach 80% by volume, resulting in a low fatigue limit. It was. In No. 17, since the Ti content was too high, a large amount of TiN was generated, and the fatigue limit was low. In No. 18, since Md (N) was too low, the amount of martensite did not reach 80% by volume, and the fatigue limit was low. In No. 19, since the C content was too high, the amount of precipitated carbide increased, and the fatigue limit was low. In No. 17, surface defects caused by TiN occurred frequently, and in No. 19, defects due to sensitization became a problem.
Claims (11)
Ｍd(Ｎ)＝５８０−５２０Ｃ−２Ｓi−１６Ｍn−１６Ｃr−２３Ｎi−２６Ｃu−３００Ｎ−１０Ｍo ……(１) In mass%, C: 0.15% or less, Si: 2.0% or less, Mn: 2.0% or less, P: 0.060% or less, S: 0.020% or less, Ni: 3.0 to 10.0%, Cr: 12.0 to 20.0%, N: 0.10% or less, Mo: 4.0% or less, Ti: 0.70% or less, O: 0.02% or less, Steel for continuously variable transmission belts, the balance of which is Fe and inevitable impurities, and whose components are adjusted so that the Md (N) value defined by the following formula (1) exceeds 100.
Md (N) = 580-520C-2Si-16Mn-16Cr-23Ni-26Cu-300N-10Mo (1)
Ｍd(Ｎ)＝５８０−５２０Ｃ−２Ｓi−１６Ｍn−１６Ｃr−２３Ｎi−２６Ｃu−３００Ｎ−１０Ｍo ……(１) In mass%, C: 0.15% or less, Si: 2.0% or less, Mn: 2.0% or less, P: 0.060% or less, S: 0.020% or less, Ni: 3.0 to 10.0%, Cr: 12.0 to 20.0%, N: 0.10% or less, Mo: 4.0% or less, Ti: 0.70% or less, O: 0.02% or less, Further, Cu: 5.0% or less, Nb: 0.50% or less, Al: 2.0% or less, B: 0.015% or less, REM: 0.20% or less, Y: 0.20% or less, Ca : Md (N) containing not less than 0.10% and Mg: not more than 0.10%, the balance being Fe and inevitable impurities, and defined by the following formula (1) ) Steel for continuously variable transmission belts whose components are adjusted so that the value exceeds 100.
Md (N) = 580-520C-2Si-16Mn-16Cr-23Ni-26Cu-300N-10Mo (1)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2003333811A JP2005097682A (en) | 2003-09-25 | 2003-09-25 | Steel, steel sheet and stock belt for continuously variable transmission belt, continuously variable transmission belt, and production method therefor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2003333811A JP2005097682A (en) | 2003-09-25 | 2003-09-25 | Steel, steel sheet and stock belt for continuously variable transmission belt, continuously variable transmission belt, and production method therefor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2005097682A true JP2005097682A (en) | 2005-04-14 |
Family
ID=34461711
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2003333811A Withdrawn JP2005097682A (en) | 2003-09-25 | 2003-09-25 | Steel, steel sheet and stock belt for continuously variable transmission belt, continuously variable transmission belt, and production method therefor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2005097682A (en) |
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007270350A (en) * | 2006-03-07 | 2007-10-18 | Kyushu Univ | High strength stainless steel and method for manufacturing high strength stainless steel |
| CN108624809A (en) * | 2017-03-24 | 2018-10-09 | 宝山钢铁股份有限公司 | Excellent seawater corrosion resistance, anti-fatigue performance and the brittle ultrahigh-strength steel plates of environment resistant and its manufacturing method |
| CN109423570A (en) * | 2017-08-23 | 2019-03-05 | 宝山钢铁股份有限公司 | A kind of steel for low-temperature pressure container and its manufacturing method |
| US20210072702A1 (en) * | 2019-09-05 | 2021-03-11 | Seiko Epson Corporation | Watch Component And Watch |
| WO2022138194A1 (en) * | 2020-12-24 | 2022-06-30 | 日鉄ステンレス株式会社 | Precipitation-hardened martensitic stainless steel having excellent fatigue-resistance characteristics |
| US11644795B2 (en) | 2019-09-05 | 2023-05-09 | Seiko Epson Corporation | Watch component and watch |
| US11669049B2 (en) | 2019-10-30 | 2023-06-06 | Seiko Epson Corporation | Watch component and watch |
| US11687038B2 (en) | 2019-12-13 | 2023-06-27 | Seiko Epson Corporation | Watch outer packaging component and watch |
| US11774913B2 (en) | 2019-11-11 | 2023-10-03 | Seiko Epson Corporation | Watch component and watch |
| US11809140B2 (en) | 2019-12-13 | 2023-11-07 | Seiko Epson Corporation | Housing and device |
-
2003
- 2003-09-25 JP JP2003333811A patent/JP2005097682A/en not_active Withdrawn
Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007270350A (en) * | 2006-03-07 | 2007-10-18 | Kyushu Univ | High strength stainless steel and method for manufacturing high strength stainless steel |
| CN108624809A (en) * | 2017-03-24 | 2018-10-09 | 宝山钢铁股份有限公司 | Excellent seawater corrosion resistance, anti-fatigue performance and the brittle ultrahigh-strength steel plates of environment resistant and its manufacturing method |
| CN109423570A (en) * | 2017-08-23 | 2019-03-05 | 宝山钢铁股份有限公司 | A kind of steel for low-temperature pressure container and its manufacturing method |
| CN109423570B (en) * | 2017-08-23 | 2020-07-28 | 宝山钢铁股份有限公司 | Steel for low-temperature pressure vessel and manufacturing method thereof |
| US11644795B2 (en) | 2019-09-05 | 2023-05-09 | Seiko Epson Corporation | Watch component and watch |
| US20210072702A1 (en) * | 2019-09-05 | 2021-03-11 | Seiko Epson Corporation | Watch Component And Watch |
| US11669048B2 (en) * | 2019-09-05 | 2023-06-06 | Seiko Epson Corporation | Watch component and watch |
| US11669049B2 (en) | 2019-10-30 | 2023-06-06 | Seiko Epson Corporation | Watch component and watch |
| US11774913B2 (en) | 2019-11-11 | 2023-10-03 | Seiko Epson Corporation | Watch component and watch |
| US11687038B2 (en) | 2019-12-13 | 2023-06-27 | Seiko Epson Corporation | Watch outer packaging component and watch |
| US11809140B2 (en) | 2019-12-13 | 2023-11-07 | Seiko Epson Corporation | Housing and device |
| TWI788143B (en) * | 2020-12-24 | 2022-12-21 | 日商日鐵不銹鋼股份有限公司 | Precipitation-hardened Asada loose iron-based stainless steel with excellent fatigue resistance |
| WO2022138194A1 (en) * | 2020-12-24 | 2022-06-30 | 日鉄ステンレス株式会社 | Precipitation-hardened martensitic stainless steel having excellent fatigue-resistance characteristics |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP6452454B2 (en) | Rolled material for high strength spring and wire for high strength spring | |
| JP4728883B2 (en) | Carburized and hardened steel and carburized parts with excellent low cycle fatigue properties | |
| JP2008280610A (en) | Carburized and high-frequency hardened part having high strength | |
| JP4872846B2 (en) | Rough shape for nitriding gear and nitriding gear | |
| WO2012077705A1 (en) | Gas-carburized steel component with excellent surface fatigue strength, gas-carburizing steel material, and process for producing gas-carburized steel component | |
| JP2009280836A (en) | High strength pc steel wire excellent in delayed crack resistance characteristic, and manufacturing method therefor | |
| JP2007177317A (en) | Steel for machine structure having excellent strength, ductility, toughness and abrasion resistance, its production method and metal belt using the same | |
| JP4252893B2 (en) | Duplex stainless steel strip for steel belt | |
| JP5505263B2 (en) | Carburized and hardened steel and carburized parts with excellent low cycle fatigue properties | |
| JP3562192B2 (en) | Component for induction hardening and method of manufacturing the same | |
| JP3421265B2 (en) | Metastable austenitic stainless steel sheet for continuously variable transmission belt and method of manufacturing the same | |
| JP7152832B2 (en) | machine parts | |
| JP2011208225A (en) | METHOD FOR PRODUCING HIGH STRENGTH COMPONENT USING Ti-B-ADDED STEEL AND HAVING EXCELLENT LOW CYCLE FATIGUE STRENGTH | |
| JP2003113449A (en) | High-strength/high-toughness stainless steel sheet superior in delayed fracture resistance and manufacturing method therefor | |
| JP2005097682A (en) | Steel, steel sheet and stock belt for continuously variable transmission belt, continuously variable transmission belt, and production method therefor | |
| JPH0421757A (en) | High surface pressure gear | |
| JP2004315968A (en) | Steel wire for high strength spring having excellent workability, and high strength spring | |
| JP5146063B2 (en) | High strength steel with excellent internal fatigue damage resistance and method for producing the same | |
| JP3470660B2 (en) | Chromium stainless steel material for spring and multi-layered structure for spring and method for producing the same | |
| JP3550886B2 (en) | Manufacturing method of gear steel for induction hardening excellent in machinability and fatigue strength | |
| JP2006265664A (en) | Method for producing belt for continuously variable transmission | |
| JP7031428B2 (en) | Steel for soaking and quenching, soaking and quenching parts and their manufacturing methods | |
| JPH08260039A (en) | Production of carburized and case hardened steel | |
| JP2002053936A (en) | Austenitic stainless steel plate for continuously variable transmission belt metallic ring and its production method | |
| JP2006265663A (en) | Steel for continuously variable transmission, stock material steel sheet, and belt for continuously variable transmission |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A300 | Withdrawal of application because of no request for examination |
Free format text: JAPANESE INTERMEDIATE CODE: A300 Effective date: 20061205 |