JP2019167578A - Maraging steel for metal belt - Google Patents
Maraging steel for metal belt Download PDFInfo
- Publication number
- JP2019167578A JP2019167578A JP2018055989A JP2018055989A JP2019167578A JP 2019167578 A JP2019167578 A JP 2019167578A JP 2018055989 A JP2018055989 A JP 2018055989A JP 2018055989 A JP2018055989 A JP 2018055989A JP 2019167578 A JP2019167578 A JP 2019167578A
- Authority
- JP
- Japan
- Prior art keywords
- maraging steel
- hardness
- strength
- metal
- metal 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.)
- Granted
Links
- 229910001240 Maraging steel Inorganic materials 0.000 title claims abstract description 42
- 239000002184 metal Substances 0.000 title claims abstract description 39
- 229910052751 metal Inorganic materials 0.000 title claims abstract description 39
- 230000032683 aging Effects 0.000 claims abstract description 28
- 229910052750 molybdenum Inorganic materials 0.000 claims abstract description 7
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 6
- 239000012535 impurity Substances 0.000 claims abstract description 6
- 229910052759 nickel Inorganic materials 0.000 claims abstract description 3
- 229910052799 carbon Inorganic materials 0.000 claims description 3
- 239000000243 solution Substances 0.000 abstract description 9
- 229910045601 alloy Inorganic materials 0.000 abstract description 8
- 239000000956 alloy Substances 0.000 abstract description 8
- 239000000203 mixture Substances 0.000 abstract description 8
- 239000006104 solid solution Substances 0.000 abstract description 2
- 230000005540 biological transmission Effects 0.000 description 14
- 238000005121 nitriding Methods 0.000 description 11
- 229910000734 martensite Inorganic materials 0.000 description 7
- 238000005728 strengthening Methods 0.000 description 7
- 229910001566 austenite Inorganic materials 0.000 description 6
- 229910000765 intermetallic Inorganic materials 0.000 description 6
- 238000001556 precipitation Methods 0.000 description 6
- 230000035882 stress Effects 0.000 description 6
- 230000007423 decrease Effects 0.000 description 5
- 150000004767 nitrides Chemical class 0.000 description 5
- 229910000831 Steel Inorganic materials 0.000 description 4
- 239000011159 matrix material Substances 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- 239000010959 steel Substances 0.000 description 4
- 230000009466 transformation Effects 0.000 description 3
- 229910000943 NiAl Inorganic materials 0.000 description 2
- NPXOKRUENSOPAO-UHFFFAOYSA-N Raney nickel Chemical compound [Al].[Ni] NPXOKRUENSOPAO-UHFFFAOYSA-N 0.000 description 2
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 238000006073 displacement reaction Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 150000001247 metal acetylides Chemical class 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 238000000137 annealing Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000005097 cold rolling Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000005242 forging Methods 0.000 description 1
- 238000005098 hot rolling Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 150000002736 metal compounds Chemical class 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000013589 supplement Substances 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
Abstract
Description
本発明は、例えば自動車用無段変速機に用いられる金属ベルト用マルエージング鋼に関するものである。 The present invention relates to maraging steel for metal belts used in, for example, continuously variable transmissions for automobiles.
マルエージング鋼は、２０００ＭＰａ前後の非常に高い引張強さをもつため、例えば、０．５ｍｍ以下の鋼帯に加工され、高強度が要求される自動車用無段変速機の金属無端ベルト等に使用されている。その代表的な組成には、質量％で１８％Ｎｉ−８％Ｃｏ−５％Ｍｏ−０．４５％Ｔｉ−０．１％Ａｌ−ｂａｌ．Ｆｅがある。しかし、上記のマルエージング鋼は、非常に高い引張強度が得られる一方、疲労強度に関しては必ずしも高くない。マルエージング鋼の疲労強度を劣化させる最大の要因にＴｉＮ介在物が挙げられる。このＴｉＮ介在物は、大きさが大きくなり易いうえに、形状も立方体であることから介在物を起点とした疲労破壊が生じ易くなる。そのため、Ｔｉを添加しないマルエージング鋼が提案されている。窒化処理される金属無端ベルト用のマルエージング鋼に含まれるＴｉは、合金の基地（マトリックス）の強度を向上させるだけでなく、窒化層の強度を高める重要元素である。このＴｉを添加しないとすると基地と窒化層の両方の強度が低下することになる。そのためＴｉを添加しないマルエージング鋼においては、Ｔｉに代わる元素を用いて基地と窒化層とを強化する必要がある。 Because maraging steel has a very high tensile strength of around 2000 MPa, it is processed into, for example, metal endless belts for continuously variable transmissions for automobiles that are processed into steel strips of 0.5 mm or less and require high strength. Has been. Its typical composition is 18% Ni-8% Co-5% Mo-0.45% Ti-0.1% Al-bal. There is Fe. However, the above-mentioned maraging steel can obtain very high tensile strength, but is not necessarily high in terms of fatigue strength. TiN inclusions can be cited as the largest factor that degrades the fatigue strength of maraging steel. The TiN inclusions are likely to increase in size and also have a cubic shape, so that fatigue failure starting from the inclusions is likely to occur. Therefore, maraging steel without adding Ti has been proposed. Ti contained in the maraging steel for a metal endless belt to be nitrided is an important element that not only increases the strength of the matrix (matrix) of the alloy but also increases the strength of the nitrided layer. If this Ti is not added, the strength of both the base and the nitrided layer will decrease. Therefore, in maraging steel to which no Ti is added, it is necessary to strengthen the matrix and the nitrided layer using an element instead of Ti.
基地と窒化層とを強化する方法としては、基地の強化に寄与するＣｏやＭｏの含有量を高めたうえで、窒化層の強化にＣｒやＡｌを用いる方法がある。この方法は、例えば、本願出願人の出願に係る国際公開ＷＯ２００９／００８０７１パンフレット（特許文献１）に開示されている。この提案は自動車無段変速機用の部材として使用される金属無端ベルトのマルエージング鋼において、Ｔｉを添加しないマルエージング鋼においても時効処理後およびガス軟窒化後に高い引張強さと内部硬さが得られることを示している。 As a method of strengthening the base and the nitride layer, there is a method of using Cr or Al for strengthening the nitride layer after increasing the content of Co or Mo contributing to the strengthening of the base. This method is disclosed, for example, in International Publication WO2009 / 008071 Pamphlet (Patent Document 1) relating to the application of the present applicant. This proposal is based on a metal endless belt maraging steel used as a member for an automobile continuously variable transmission, and even in a maraging steel to which no Ti is added, high tensile strength and internal hardness are obtained after aging treatment and after gas soft nitriding. It is shown that.
上述した特許文献１で示したマルエージング鋼は、Ｔｉを添加しないマルエージング鋼においても高い強度が得られる点では有利であるものの、開示された成分範囲において、時効処理およびガス軟窒化後の強度水準は大きく変化しており、製造性の点では安定した機械的特性を得るのが難しいという問題があった。金属ベルト用マルエージング鋼は、内部硬さが高すぎると材料内部欠陥起因で早期に破断し、また内部硬さが低すぎると低応力下で塑性変形するため硬さや強度などの機械的特性の変化が大きいと実用化する上で大きな問題となる。
本発明の目的は、金属ベルト用マルエージング鋼の合金組成に起因する強度や硬さ水準を適正化することで、製造性や機械的特性に優れる金属ベルト用マルエージング鋼を提供することである。
Although the maraging steel shown in Patent Document 1 described above is advantageous in that high strength can be obtained even in maraging steel not containing Ti, in the disclosed component range, strength after aging treatment and gas soft nitriding The level has changed greatly, and there has been a problem that it is difficult to obtain stable mechanical characteristics in terms of manufacturability. If the internal hardness is too high, the maraging steel for metal belts will break early due to internal defects in the material, and if the internal hardness is too low, it will be plastically deformed under low stress, so it has mechanical properties such as hardness and strength. If the change is large, it becomes a big problem in practical use.
An object of the present invention is to provide a maraging steel for metal belts that is excellent in manufacturability and mechanical properties by optimizing the strength and hardness level resulting from the alloy composition of the maraging steel for metal belts. .
本発明者は、合金成分に起因した強度水準の大きな変化に対し、Ｃｒ、Ｍｏ、Ｃｏ、Ａｌの添加量を適正範囲に管理することで安定した機械的特性が得られることを見いだし本発明に到達した。
すなわち本発明は、質量％で、Ｃ：０．０１％以下、Ｎｉ：１８．０〜２０．０％、Ｃｒ：０．８〜１．２％、Ｍｏ：４．５〜６．０％、Ｃｏ：９．０〜１４．０％、Ａｌ：０．８〜１．７％、残部は、Ｆｅ及び不可避的不純物でなる金属ベルト用マルエージング鋼である。
好ましくは、前記マルエージング鋼は、９００℃×１時間の固溶化処理と４８０℃×１時間の時効処理を行ったとき、ビッカース硬さで５５０ＨＶ以上の硬さを有する金属ベルト用マルエージング鋼である。
好ましくは、前記マルエージング鋼は、９００℃×１時間の固溶化処理と４８０℃×３時間の時効処理を行ったとき、ビッカース硬さで６００ＨＶ以上の硬さを有する金属ベルト用マルエージング鋼である。
The present inventor has found that stable mechanical characteristics can be obtained by managing the addition amount of Cr, Mo, Co, and Al within an appropriate range against a large change in strength level caused by the alloy components. Reached.
That is, the present invention is mass%, C: 0.01% or less, Ni: 18.0-20.0%, Cr: 0.8-1.2%, Mo: 4.5-6.0%, Co: 9.0 to 14.0%, Al: 0.8 to 1.7%, and the balance is maraging steel for metal belt made of Fe and inevitable impurities.
Preferably, the maraging steel is a maraging steel for metal belts having a Vickers hardness of 550 HV or higher when a solution treatment at 900 ° C. × 1 hour and an aging treatment at 480 ° C. × 1 hour are performed. is there.
Preferably, the maraging steel is a maraging steel for metal belts having a Vickers hardness of 600 HV or higher when a solution treatment at 900 ° C. × 1 hour and an aging treatment at 480 ° C. × 3 hours are performed. is there.
本発明の金属ベルト用マルエージング鋼は合金組成に起因する強度や硬さ水準を適正化することで、優れた製造性を有しており，自動車用無段変速機の金属無端ベルトのように強度と製造性が要求される部材に使用されると安定した機械的特性が得られるなど、工業的な効果を持つことが期待される。 The maraging steel for metal belts of the present invention has excellent manufacturability by optimizing the strength and hardness level resulting from the alloy composition, like the metal endless belt of a continuously variable transmission for automobiles. When used for members that require strength and manufacturability, it is expected to have industrial effects such as obtaining stable mechanical properties.
上述したように、本発明の重要な特徴は安定した製造性と機械的特性を得るために必要な合金組成を適正化したことにある。
本発明の金属ベルト用マルエージング鋼において、以下の範囲で各化学組成を規定した理由は以下の通りである。なお、特に記載のない限り質量％として記す。
＜Ｃ：０．０１％以下＞
Ｃ（炭素）は、ＭｏやＣｒと炭化物を形成して、析出すべき金属間化合物や窒化物を減少させて強度を低下させるため、低く抑える必要がある。また、Ｃを積極添加すると、例えば無段変速機部品に必要とされる溶接性が低下する危険性が高くなる。このような理由からＣは０．０１％以下とした。好ましくは、０．００８％以下である。一方で、Ｃの微量添加は微細な炭化物を形成し、強度向上に寄与することから０．００１％以上が好ましい。
As described above, an important feature of the present invention is that the alloy composition necessary for obtaining stable manufacturability and mechanical properties is optimized.
In the maraging steel for metal belts of the present invention, the reason why each chemical composition is specified in the following range is as follows. Unless otherwise specified, the mass% is indicated.
<C: 0.01% or less>
C (carbon) needs to be kept low because it forms carbides with Mo and Cr and reduces the strength of the intermetallic compound and nitride to be precipitated. Further, if C is positively added, there is a high risk that the weldability required for, for example, a continuously variable transmission component will be reduced. For these reasons, C is set to 0.01% or less. Preferably, it is 0.008% or less. On the other hand, addition of a small amount of C forms fine carbides and contributes to improvement in strength, so 0.001% or more is preferable.
＜Ｎｉ：１８．０〜２０．０％＞
Ｎｉは、金属ベルト用マルエージング鋼の基地組織である低Ｃマルテンサイト組織を安定して形成させるため、少なくとも１８．０％は必要である。しかし、２０．０％を超えるとオーステナイト組織が安定化し、マルテンサイト変態を起こし難くなることから、Ｎｉは１８．０〜２０．０％とした。Ｎｉの好ましい上限は１８．５％超であり、好ましい下限は１９．５％である。
＜Ｃｒ：０．８〜１．２％＞
Ｃｒは、窒化を行う場合にＮとの親和力が強く、窒化深さを浅くし、窒化硬さを高めたり、窒化表面の圧縮残留応力を増加させたりする元素であるため、必須で添加する。しかし、０．８％より少ないと効果が小さく、一方で１．２％を越えると窒化硬さが高くなり過ぎてしまい、金属ベルトの製造工程の中で不可避的に形成される表面傷などの欠陥に対する感受性が高まり、疲労強度が低下することからＣｒは０．８〜１．２％とした。Ｃｒのより好ましい下限は０．９％であり、好ましい上限は１．１％である。
<Ni: 18.0 to 20.0%>
Ni needs to be at least 18.0% in order to stably form a low C martensite structure, which is a base structure of maraging steel for metal belts. However, if it exceeds 20.0%, the austenite structure is stabilized and it is difficult to cause martensitic transformation, so Ni was made 18.0 to 20.0%. A preferable upper limit of Ni is more than 18.5%, and a preferable lower limit is 19.5%.
<Cr: 0.8 to 1.2%>
Cr is an element that has a strong affinity for N when nitriding, reduces the nitriding depth, increases the nitriding hardness, and increases the compressive residual stress on the nitriding surface, so is essential. However, if the content is less than 0.8%, the effect is small. On the other hand, if the content exceeds 1.2%, the nitriding hardness becomes too high, and surface scratches inevitably formed in the metal belt manufacturing process. Since the susceptibility to defects increases and the fatigue strength decreases, the Cr content is set to 0.8 to 1.2%. A more preferable lower limit of Cr is 0.9%, and a preferable upper limit is 1.1%.
＜Ｍｏ：４．５〜６．０％＞
Ｍｏは、時効処理時にＮｉ３Ｍｏ等の微細な金属間化合物を形成し、析出強化に寄与する重要な元素である。また、Ｍｏは窒化による表面の硬さ及び圧縮残留応力を大きくするために有効な元素である。このためのＭｏは、４．５％より少ないと金属化合物の析出量の低下により引張強度が不十分となり、一方、６．０％より多いとＦｅ、Ｍｏを主要元素とする粗大な金属間化合物を形成しやすくなるとともに固溶化処理で形成されるオーステナイト相を固溶強化するため冷却過程でマルテンサイト変態を阻害するためＭｏは４．５〜６．０％とした。Ｍｏの好ましい下限は４．５％超であり、好ましい上限は５．８％である。
＜Ｃｏ：９．０〜１４．０％＞
Ｃｏは、マトリックスのマルテンサイト組織の安定性に大きく影響することなく、固溶化処理温度で時効析出物形成元素であるＭｏの固溶度を増加させ、時効析出温度域でのＭｏの固溶度を低下させることによってＭｏを含む微細な金属間化合物の析出を促進し、時効析出強化に寄与する重要な元素である。そのため、Ｃｏは強度面、靭性面から多く添加することが必要である。Ｃｏが９．０％未満ではＴｉを低減した金属ベルト用マルエージング鋼では十分な強度が得られ難く、一方１４．０％を超えて添加するとオーステナイトが安定化してマルテンサイト組織が得られ難くなることから、９．０％以上１４．０％以下とした。好ましいＣｏの下限は１０．０％超であり、好ましい上限は１３．５％である。
<Mo: 4.5-6.0%>
Mo is an important element that contributes to precipitation strengthening by forming fine intermetallic compounds such as Ni 3 Mo during aging treatment. Mo is an effective element for increasing the surface hardness and compressive residual stress due to nitriding. For this purpose, if Mo is less than 4.5%, the tensile strength becomes insufficient due to a decrease in the amount of precipitated metal compound, whereas if it exceeds 6.0%, a coarse intermetallic compound containing Fe and Mo as main elements. In order to inhibit the martensitic transformation during the cooling process in order to strengthen the austenite phase formed by the solution treatment and to enhance the solid solution, the Mo content is set to 4.5 to 6.0%. The preferable lower limit of Mo is more than 4.5%, and the preferable upper limit is 5.8%.
<Co: 9.0 to 14.0%>
Co increases the solid solubility of Mo, which is an aging precipitate forming element, at the solution treatment temperature without greatly affecting the stability of the martensitic structure of the matrix, and the solubility of Mo in the aging precipitation temperature range is increased. Is an important element that promotes the precipitation of fine intermetallic compounds containing Mo and contributes to strengthening of aging precipitation. Therefore, it is necessary to add much Co in terms of strength and toughness. When Co is less than 9.0%, it is difficult to obtain sufficient strength with a maraging steel for metal belts with reduced Ti. On the other hand, when it exceeds 14.0%, austenite is stabilized and it is difficult to obtain a martensite structure. Therefore, the content was set to 9.0% or more and 14.0% or less. The preferable lower limit of Co is more than 10.0%, and the preferable upper limit is 13.5%.
＜Ａｌ：０．８〜１．７％＞
Ａｌは、通常、脱酸のために少量添加されるが、本来、時効処理時にＮｉと共にＮｉＡｌを形成して強化に寄与する元素である。Ｔｉを無添加とした本発明の金属ベルト用マルエージング鋼ではＡｌの添加によって強度を補う必要がある。また、Ｔｉを無添加とした金属ベルト用マルエージング鋼において窒化処理を容易にして良好な窒化層を得るためにもＡｌの添加が必要である。Ａｌは、０．８％未満では時効処理による十分な強化作用が得られず、一方１．７％より多いと窒化層が硬くなりすぎてしまい疲労強度を低下させたり、表面に薄くて安定な酸化膜を形成して窒化反応を阻害したりすることから、Ａｌは０．８％以上１．７％以下とした。好ましいＡｌの下限は０．９％であり、好ましいＡｌの上限は１．６％である。
＜残部：Ｆｅ及び不純物＞
残部は実質的にＦｅであるが、製造上不可避的に混入する不純物は含まれる。不純物含有量は少ない方が好ましいが、以下の範囲であれば差し支えない。
Ｐ≦０．０５％、Ｓ≦０．０５％、Ｚｒ≦０．０１％、Ｃａ≦０．０1％、Ｍｇ≦０．００５％、Ｎ≦０．０５％
<Al: 0.8 to 1.7%>
Al is usually added in a small amount for deoxidation, but is originally an element that contributes to strengthening by forming NiAl together with Ni during aging treatment. In the maraging steel for metal belts of the present invention in which Ti is not added, it is necessary to supplement the strength by adding Al. In addition, in order to obtain a good nitrided layer by facilitating nitriding in a maraging steel for metal belts without addition of Ti, addition of Al is necessary. If Al is less than 0.8%, sufficient strengthening action due to the aging treatment cannot be obtained. On the other hand, if it exceeds 1.7%, the nitride layer becomes too hard and fatigue strength is reduced, and the surface is thin and stable. Since the oxide film is formed to inhibit the nitriding reaction, Al is made 0.8% to 1.7%. A preferable lower limit of Al is 0.9%, and a preferable upper limit of Al is 1.6%.
<Balance: Fe and impurities>
The balance is substantially Fe, but includes impurities that are inevitably mixed in production. Although it is preferable that the impurity content is small, it may be within the following range.
P ≦ 0.05%, S ≦ 0.05%, Zr ≦ 0.01%, Ca ≦ 0.01%, Mg ≦ 0.005%, N ≦ 0.05%
次に本発明で規定した熱処理後のビッカース硬さについて説明する。
本発明の金属ベルト用マルエージング鋼は自動車用無段変速機の部材として使用される場合、固溶化処理および時効処理などの調質熱処理と窒化処理などの表面処理を経て使用される。９００℃×１時間の固溶化処理は金属間化合物や窒化物の析出に必要な合金元素を母相のオーステナイト中に固溶させ、時効処理ではＮｉ３ＭｏやＮｉＡｌなどの金属間化合物を析出させることを目的にしている。
本発明では４８０℃における時効時間を１時間と３時間とし、時効処理後のビッカース硬さをそれぞれ５５０ＨＶ以上と６００ＨＶ以上としている。４８０℃で１時間の時効処理は製造性を考慮したもので、短時間時効で自動車用無段変速機の金属無段ベルトに必要とされる硬さ水準の５５０ＨＶ以上を得るために規定したものである。硬さが５５０ＨＶよりも低いと、例えば金属ベルトに引張の応力が作用した場合、容易に塑性変形してしまい、機械部品として使用することができなくなる。一方、４８０℃で３時間の時効処理は金属ベルトの高強度化を考慮したもので、硬度を６００ＨＶ以上とすることで自動車変速機の金属ベルトの許容できる応力レベルを高めることができるため、無段変速機の高トルク化や高排気量化に貢献することが期待できる。一方で、６００ＨＶよりも低いと、例えば金属ベルトに高排気量化や高トルク化に伴う高い応力が作用した場合、塑性変形のおそれがある。
Next, the Vickers hardness after the heat treatment defined in the present invention will be described.
When the maraging steel for a metal belt of the present invention is used as a member of a continuously variable transmission for an automobile, it is used after a heat treatment such as a solution treatment and an aging treatment and a surface treatment such as a nitriding treatment. The solution treatment at 900 ° C. for 1 hour causes the alloy elements necessary for precipitation of intermetallic compounds and nitrides to be dissolved in the austenite of the parent phase, and the aging treatment precipitates intermetallic compounds such as Ni 3 Mo and NiAl. It is aimed at that.
In the present invention, the aging time at 480 ° C. is 1 hour and 3 hours, and the Vickers hardness after the aging treatment is 550 HV or more and 600 HV or more, respectively. The aging treatment for 1 hour at 480 ° C. is based on manufacturability, and is specified for obtaining a hardness level of 550 HV or more required for metal continuously variable belts for continuously variable transmissions for automobiles with short-term aging. It is. When the hardness is lower than 550 HV, for example, when a tensile stress is applied to the metal belt, it is easily plastically deformed and cannot be used as a machine part. On the other hand, the aging treatment for 3 hours at 480 ° C. is intended to increase the strength of the metal belt. By setting the hardness to 600 HV or higher, the allowable stress level of the metal belt of the automobile transmission can be increased. It can be expected to contribute to higher torque and higher displacement of the step transmission. On the other hand, if it is lower than 600 HV, for example, when a high stress is applied to the metal belt due to an increase in displacement or torque, there is a risk of plastic deformation.
以上に説明する本発明の金属ベルト用マルエージング鋼を使用すれば、合金組成に起因する強度や硬さ水準を適正化でき、製造性や機械的特性に優れる金属ベルト用マルエージング鋼とすることができる。
本発明のマルエージング鋼から構成される鋼帯は主に自動車用無段変速機に使用される金属無端ベルトとて使用されることから引張強さや疲労強度に代表される機械的特性を向上させた動力伝達用ベルトのリング素材として最適である。
If the maraging steel for metal belts of the present invention described above is used, the strength and hardness level resulting from the alloy composition can be optimized, and the maraging steel for metal belts excellent in manufacturability and mechanical properties. Can do.
The steel strip composed of the maraging steel of the present invention is mainly used as a metal endless belt used in a continuously variable transmission for automobiles, and therefore improves mechanical properties represented by tensile strength and fatigue strength. Ideal as a ring material for a power transmission belt.
以下の実施例で本発明を更に詳しく説明する。
真空溶解で２００ｋｇ鋼塊を作製し、鍛造、熱間圧延を行い、焼鈍と冷間圧延を繰返して、幅が１８０ｍｍ、厚さ０．４２ｍｍの金属ベルト用マルエージング鋼帯を作製した。その後、９００℃で１時間の固溶化処理を行ない、更に４８０℃で１時間と３時間の時効処理を行なった。この実施例の化学組成を表１に示す。
また、表２に各試料を時効した後の内部硬さを示す。なお、硬さはビッカース硬度計を用い、荷重５００ｇｆで測定した。
The following examples further illustrate the present invention.
A 200 kg steel ingot was produced by vacuum melting, forging and hot rolling were performed, and annealing and cold rolling were repeated to produce a maraging steel strip for a metal belt having a width of 180 mm and a thickness of 0.42 mm. Thereafter, a solution treatment was performed at 900 ° C. for 1 hour, and an aging treatment was further performed at 480 ° C. for 1 hour and 3 hours. The chemical composition of this example is shown in Table 1.
Table 2 shows the internal hardness after aging each sample. The hardness was measured using a Vickers hardness tester with a load of 500 gf.
表２より、本発明の金属ベルト用マルエージング鋼Ｎｏ．１〜３は、何れも４８０℃で１時間の時効処理後のビッカース硬さが５５０ＨＶ以上が得られた。４８０℃で３時間の時効後のビッカース硬さは、５８０ＨＶ以上であり、自動車用変速機の金属ベルト用途として十分な内部硬さを有している。中でも特に、Ｎｏ．１及び２のマルエージング鋼については、６００ＨＶ以上の硬さが得られた。
一方でＭｏ添加量が６．４％と高い比較例のＮｏ．１０は、４８０℃で３時間の時効処理後のビッカース硬さが４７２ＨＶと低い値となっている。Ｍｏ添加量が高いため、固溶化処理時にＭｏがオーステナイト相を安定化しマルテンサイト変態を抑制するともに、時効処理により不安定なマルテンサイト相が逆変態オーステナイト相へと変化したことでビッカース硬さが低下したと考えられる。Ｃｏ添加量が８％と低い比較例のＮｏ．１１は、時効処理後のビッカース硬さが１時間で５４３ＨＶ、３時間で５７４ＨＶと低い。これはＣｏ添加量の低下に起因したＮｉ３Ｍｏ析出量の減少によるものと考えられる。
From Table 2, the maraging steel no. 1 to 3, Vickers hardness after aging treatment at 480 ° C. for 1 hour was 550 HV or more. The Vickers hardness after aging at 480 ° C. for 3 hours is 580 HV or more, and has sufficient internal hardness for use as a metal belt in an automobile transmission. Especially, no. For the maraging steels 1 and 2, a hardness of 600 HV or higher was obtained.
On the other hand, No. of a comparative example with Mo addition amount as high as 6.4%. No. 10 has a low Vickers hardness of 472 HV after aging treatment at 480 ° C. for 3 hours. Since the amount of Mo added is high, Mo stabilizes the austenite phase during the solution treatment and suppresses martensitic transformation, and the unstable martensite phase changes to the reverse transformed austenite phase due to aging treatment. It is thought that it fell. Comparative Example No. with a low Co addition amount of 8% No. 11 has a low Vickers hardness after aging treatment of 543 HV in 1 hour and 574 HV in 3 hours. This is considered to be due to a decrease in the amount of Ni 3 Mo precipitation due to a decrease in the amount of Co addition.
本発明の金属ベルト用マルエージング鋼は、過酷な条件で使用される金属ベルトに用いることが可能であるため、自動車用無段変速機等に使用される動力伝達金属ベルトのような高引張強度、高疲労強度が要求される部材に適用できる。
Since the maraging steel for metal belts of the present invention can be used for metal belts used under severe conditions, it has high tensile strength like power transmission metal belts used for continuously variable transmissions for automobiles. It can be applied to members that require high fatigue strength.
Claims (3)
2. The maraging steel has a Vickers hardness of 600 HV or more when subjected to a solution treatment at 900 ° C. × 1 hour and an aging treatment at 480 ° C. × 3 hours. Maraging steel for metal belts.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2018055989A JP7172080B2 (en) | 2018-03-23 | 2018-03-23 | Maraging steel for metal belts |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2018055989A JP7172080B2 (en) | 2018-03-23 | 2018-03-23 | Maraging steel for metal belts |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2019167578A true JP2019167578A (en) | 2019-10-03 |
| JP7172080B2 JP7172080B2 (en) | 2022-11-16 |
Family
ID=68106430
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2018055989A Active JP7172080B2 (en) | 2018-03-23 | 2018-03-23 | Maraging steel for metal belts |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP7172080B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP7447377B2 (en) | 2020-03-24 | 2024-03-12 | 株式会社プロテリアル | Manufacturing method of Ti-free maraging steel |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002167652A (en) * | 2000-11-28 | 2002-06-11 | Daido Steel Co Ltd | Thin sheet material excellent in high strength-high fatigue resisting characteristic |
| JP2009013464A (en) * | 2007-07-04 | 2009-01-22 | Hitachi Metals Ltd | Maraging steel for metal belt |
| WO2010110379A1 (en) * | 2009-03-26 | 2010-09-30 | 日立金属株式会社 | Maraging steel strip |
-
2018
- 2018-03-23 JP JP2018055989A patent/JP7172080B2/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002167652A (en) * | 2000-11-28 | 2002-06-11 | Daido Steel Co Ltd | Thin sheet material excellent in high strength-high fatigue resisting characteristic |
| JP2009013464A (en) * | 2007-07-04 | 2009-01-22 | Hitachi Metals Ltd | Maraging steel for metal belt |
| WO2010110379A1 (en) * | 2009-03-26 | 2010-09-30 | 日立金属株式会社 | Maraging steel strip |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP7447377B2 (en) | 2020-03-24 | 2024-03-12 | 株式会社プロテリアル | Manufacturing method of Ti-free maraging steel |
Also Published As
| Publication number | Publication date |
|---|---|
| JP7172080B2 (en) | 2022-11-16 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP5429651B2 (en) | Maraging steel strip | |
| US6767414B2 (en) | Maraging steel having high fatigue strength and maraging steel strip made of same | |
| WO2012077705A1 (en) | Gas-carburized steel component with excellent surface fatigue strength, gas-carburizing steel material, and process for producing gas-carburized steel component | |
| JP5034803B2 (en) | Steel sheet for soft nitriding treatment and method for producing the same | |
| JP2011153364A (en) | Crankshaft and method for producing the same | |
| JP5046363B2 (en) | Maraging steel for power transmission belt with high fatigue strength and maraging steel strip for power transmission belt using the same | |
| EP2180073B1 (en) | Maraging steel for metallic belt | |
| JP5333686B1 (en) | Maraging steel | |
| JP2010189697A (en) | Crankshaft and method for producing the same | |
| JP2003113449A (en) | High-strength/high-toughness stainless steel sheet superior in delayed fracture resistance and manufacturing method therefor | |
| JP5007930B2 (en) | Maraging steel having high fatigue strength, maraging steel strip using the same, and method for producing maraging steel having high fatigue strength | |
| JP7172080B2 (en) | Maraging steel for metal belts | |
| JP2006028568A (en) | Steel for high temperature carburizing and its production method | |
| JP4451919B1 (en) | Steel sheet and manufacturing method thereof, and steel belt for continuously variable transmission | |
| JP4507149B2 (en) | Maraging steel for power transmission belt with high fatigue strength and maraging steel strip for power transmission belt using the same | |
| JP2001240943A (en) | Maraging steel with high fatigue strength, and maraging steel strip using it | |
| JP4178490B2 (en) | Maraging steel with high fatigue strength and maraging steel strip using it | |
| JP4307329B2 (en) | Piston ring wire and piston ring | |
| JP7447377B2 (en) | Manufacturing method of Ti-free maraging steel | |
| JP4821711B2 (en) | Steel for soft nitriding | |
| JP7167482B2 (en) | Non-heat treated steel for nitriding and crankshaft | |
| JP2005163181A (en) | Carburizing heat treatment method of case-hardening boron steel having excellent crystal grain size characteristic | |
| JP2008075136A (en) | Steel material composed of nitriding steel for cold-working excellent in weldability and strong characteristic, and nitriding steel part composed of this steel material |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20210215 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20220224 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20220317 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20220422 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20220823 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20220901 |
|
| 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: 20221004 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20221017 |
|
| R150 | Certificate of patent or registration of utility model |
Ref document number: 7172080 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| 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 |