JP2020015927A - Alloy steel for mechanical structure excellent in impact resistance - Google Patents
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本発明は、土木、建設等の分野で使用される土木建設機械等に使用される機械構造用合金鋼に関し、とりわけ土砂や岩石等との摩耗や折損が問題となる環境下で使用される部材として良好な機械構造用合金鋼に関する。 The present invention relates to an alloy steel for a machine structure used for a civil engineering and construction machine used in the fields of civil engineering and construction, etc., and in particular, a member used in an environment where wear and breakage with earth and sand, rocks and the like becomes a problem. As an alloy steel for machine structural use.
土木建設機械に使用される部材は、岩石等を割る際には折損等が生じることがある。また土砂、岩石等によって摩耗も引き起こされる。近年、土木建設機械の使用される環境はますます過酷になってきており、早期折損、早期摩耗が問題視されている。こうした早期折損に対しては部材の靱性を向上させること、早期摩耗に対しては部材を高強度化、高硬度化させる必要がある。 Members used in civil engineering and construction machines may break when rocks or the like are broken. Wear is also caused by soil, rocks and the like. In recent years, the environment in which civil engineering and construction machines are used has become increasingly severe, and early breakage and early wear have been regarded as problems. It is necessary to improve the toughness of the member against such early breakage, and to increase the strength and hardness of the member against early wear.
また、土木建設機械用の部材は大型の部品であることが多いために、焼入れ時に完全に中心部まで硬化させる必要がある。さらに、焼入れ硬化層が浅い場合、表面部の硬化層が一旦摩耗しきってしまうとその内部は急激に摩耗してしまう。そこで、土木建設機械用鋼にはより良好な硬度と靱性とのバランスが求められている。しかしながら、靱性と耐摩耗性はトレードオフの関係にある。たとえば、低温焼入れによると高硬度が得られるものの靱性は低くなりやすいように、それらの両立は一般的に困難である。 In addition, members for civil engineering and construction machines are often large components, and thus need to be completely hardened to the center during quenching. Furthermore, when the hardened hardened layer is shallow, once the hardened layer on the surface is completely worn, the inside thereof is rapidly worn. Therefore, steel for civil engineering construction machines is required to have a better balance between hardness and toughness. However, there is a trade-off between toughness and wear resistance. For example, it is generally difficult to achieve a high hardness by low-temperature quenching so that a high hardness is obtained but a toughness tends to be low.
従来、土砂や岩石などによる摩耗が問題となる土木建設機械に使用される部材に対しては、Ｃｒ、Ｍｏ等の合金元素を多量に添加した鋼材に焼入れを行い、高硬度化した鋼材が使用されている。 Conventionally, for members used in civil engineering and construction equipment where wear due to earth and sand, rocks, etc. poses a problem, steel materials with a large amount of alloying elements such as Cr and Mo are quenched and steel materials with high hardness are used. Have been.
またＣ添加による高硬度化、Ｓｉ、Ｃｒ添加による焼入性の増大、Ｓｉ添加による焼戻軟化抵抗性の向上により、耐摩耗性の向上を志向する方法が提案されている（例えば、特許文献１参照）。しかし、この提案の方法では、硬度向上のためにＣを増加するものの、他方で靱性が低下するという問題が生じてしまう。また、焼入性向上のためにＳｉ、Ｃｒを多量に添加しているものの、今度は過剰な焼入性によって製造性が低下することも懸念される。 Further, there has been proposed a method of improving wear resistance by increasing hardness by adding C, increasing hardenability by adding Si and Cr, and improving tempering softening resistance by adding Si (for example, Patent Document 1). 1). However, in the method of this proposal, although C is increased to improve hardness, on the other hand, there is a problem that toughness is reduced. In addition, although a large amount of Si and Cr is added to improve the hardenability, there is a concern that the excess hardenability may lower the productivity.
次に、Ｂ添加による粒界強化によって靱性の向上を図るとともに、Ｓｉの添加による固溶強化によって耐摩耗性の向上を志向する方法も提案されている（例えば、特許文献２参照）。しかし、この提案の方法では、Ｍｎ、Ｂの添加により焼入性の向上が図られるものの、合金元素が不足しているために焼入性が未だ低く十分とはいえない。すると、大型部材に対し焼入れを行った場合には中心部までの硬化が得られないこととなることから、耐摩耗性が十分とはいえなかった。 Next, a method has been proposed in which toughness is improved by grain boundary strengthening by adding B and wear resistance is enhanced by solid solution strengthening by adding Si (for example, see Patent Document 2). However, in this proposed method, although the hardenability is improved by the addition of Mn and B, the hardenability is still low and not sufficient because the alloying elements are insufficient. Then, when quenching was performed on the large member, hardening up to the center could not be obtained, so that the abrasion resistance was not sufficient.
また、Ｍｎ、Ｃｒ、Ｍｏの複合添加により焼入性、焼戻軟化抵抗性の向上および靱性の向上を志向する方法が提案されている（例えば、特許文献３参照。）。しかし、Ｍｎの添加により粒界への炭化物の偏析が大きくなるので、靱性を低下させる要因となる。また、Ｍｏの添加により成分偏析が大きくなることによって靱性が低下したり、過剰な焼入性によって製造性が低下すること等も懸念される。 In addition, a method has been proposed in which the addition of Mn, Cr, and Mo is aimed at improving hardenability, temper softening resistance, and toughness (for example, see Patent Document 3). However, the addition of Mn increases the segregation of carbides at grain boundaries, which causes a reduction in toughness. In addition, there is a concern that the addition of Mo may increase the segregation of the components, thereby lowering the toughness, or the excessive hardenability may lower the productivity.
そこで、本発明が解決しようとする課題は、土木建設機械用部材、例えばトラックリンク、トラックシュー、リッパーポイント等のような大型の部材にも適用可能で、かつ厳しい衝撃が加わったり摩耗が生じやすい厳しい環境下での使用に適した鋼材として、中心部までの焼入れ性に優れる機械構造用合金鋼を提供することである。 Therefore, the problem to be solved by the present invention is applicable to members for civil engineering and construction equipment, for example, large members such as track links, track shoes, ripper points, etc., and is subject to severe impact or wear. An object of the present invention is to provide an alloy steel for machine structural use having excellent hardenability up to the center as a steel material suitable for use in a severe environment.
また、上記の機械構造用合金鋼を焼入焼戻し処理した際に、優れた硬度と靱性とを兼ね備えている機械構造用合金鋼の提供、すなわち、土木建設機械用部材に好適な、焼入焼戻し後の鋼材中心部の硬さが４５ＨＲＣ以上、２ｍｍＶノッチシャルピー衝撃試験により測定した衝撃値が３５Ｊ／ｃｍ2であることを満たす硬度と靱性に優れる機械構造用合金鋼を提供することである。 Further, when the above-mentioned alloy steel for machine structure is subjected to quenching and tempering treatment, provision of alloy steel for machine structure having both excellent hardness and toughness, that is, quenching and tempering suitable for members for civil engineering construction machinery It is an object of the present invention to provide an alloy steel for machine structural use having excellent hardness and toughness that satisfies that the hardness at the center of the steel material after that is 45 HRC or more and the impact value measured by a 2 mm V notch Charpy impact test is 35 J / cm 2 .
本願の発明者らは、焼入焼戻し処理を施して用いられる土木建設機械用部材に対し、Ｓｉの低減によって粒界炭化物を抑制し、またＡｌ、Ｎの添加によりピンニング粒子であるＡｌＮを析出させることによって結晶粒粗大化を防止することで靱性を改善し、さらにＣ、Ｍｎ、Ｃｒ、Ｍｏを適切に添加することにより、焼入れ時に鋼材の中心部まで焼入れ硬化する、靱性と耐摩耗性の双方に優れる鋼を見出した。 The inventors of the present application suppress the grain boundary carbides by reducing Si, and precipitate AlN, which is pinning particles, by adding Al and N to the civil engineering construction machine member used by performing the quenching and tempering treatment. This improves toughness by preventing crystal grain coarsening, and furthermore, by adding C, Mn, Cr, and Mo appropriately, quench hardens to the center of the steel material during quenching, and provides both toughness and wear resistance. Steel that is excellent in quality.
そこで、本発明の課題を解決するための第１の手段では、質量％で、Ｃ：０．２５〜０．４０％、Ｓｉ：０．０５〜０．３０％、Ｍｎ：１．００〜１．５０％、Ｐ：０．０３０％以下、Ｓ：０．０３０％以下、Ｃｒ：１．５０〜３．００％、Ｍｏ：０．０５〜０．５０％、Ａｌ：０．０２０〜０．０５０％、Ｎ：０．０１００〜０．０２００％を含有し、残部がＦｅおよび不可避的不純物からなり、以下の式（１）のＡの値が１０以上２０以下であることを特徴とする機械構造用合金鋼である。
Ａ＝０．５Ｃ×（１＋０．７Ｓｉ）×（１＋３．６Ｍｎ）×（１＋２．２Ｃｒ）×（１＋３．０Ｍｏ）・・・式（１）
ただし、式中の元素記号には、各元素の含有率（質量％）を代入する。
Therefore, in a first means for solving the problem of the present invention, in mass%, C: 0.25 to 0.40%, Si: 0.05 to 0.30%, Mn: 1.00 to 1 .50%, P: 0.030% or less, S: 0.030% or less, Cr: 1.50 to 3.00%, Mo: 0.05 to 0.50%, Al: 0.020 to 0. 050%, N: 0.0100 to 0.0200%, the balance being Fe and unavoidable impurities, wherein the value of A in the following formula (1) is 10 or more and 20 or less. It is a structural alloy steel.
A = 0.5C × (1 + 0.7Si) × (1 + 3.6Mn) × (1 + 2.2Cr) × (1 + 3.0Mo) Formula (1)
However, the content (% by mass) of each element is substituted for the element symbol in the formula.
第２の手段では、第１の手段の化学成分に加えて、質量％でＮｂ：０．０２〜０．０４％、Ｔｉ：０．００５〜０．０３０％のうち一種または二種を含有し、ＮｂとＴｉの質量％の合計値は０．００５≦（Ｎｂ＋Ｔｉ）≦０．０５０を満足するものであって、残部がＦｅおよび不可避的不純物からなり、以下の式（１）のＡの値が１０以上２０以下であることを特徴とする機械構造用合金鋼である。
Ａ＝０．５Ｃ×（１＋０．７Ｓｉ）×（１＋３．６Ｍｎ）×（１＋２．２Ｃｒ）×（１＋３．０Ｍｏ）・・・式（１）
ただし、式中の元素記号には、各元素の含有率（質量％）を代入する。
In the second means, one or two of Nb: 0.02 to 0.04% and Ti: 0.005 to 0.030% by mass% are contained in addition to the chemical components of the first means. , Nb and Ti satisfy the relationship of 0.005 ≦ (Nb + Ti) ≦ 0.050, the balance being Fe and unavoidable impurities, and the value of A in the following formula (1). Is not less than 10 and not more than 20.
A = 0.5C × (1 + 0.7Si) × (1 + 3.6Mn) × (1 + 2.2Cr) × (1 + 3.0Mo) Formula (1)
However, the content (% by mass) of each element is substituted for the element symbol in the formula.
第３の手段は、質量％で、Ｃ：０．２５〜０．４０％、Ｓｉ：０．０５〜０．３０％、Ｍｎ：１．００〜１．５０％、Ｐ：０．０３０％以下、Ｓ：０．０３０％以下、Ｃｒ：１．５０〜３．００％、Ｍｏ：０．０５〜０．５０％、Ａｌ：０．０２０〜０．０５０％、Ｎ：０．０１００〜０．０２００％を含有し、残部がＦｅおよび不可避的不純物からなり、
以下の式（１）のＡの値が１０以上２０以下であって、
さらにオーステナイト化温度より３０℃〜１００℃高い加熱温度から焼入焼戻し処理した場合、焼入硬さが４５ＨＲＣ以上となっていることを特徴とする機械構造用合金鋼である。
Ａ＝０．５Ｃ×（１＋０．７Ｓｉ）×（１＋３．６Ｍｎ）×（１＋２．２Ｃｒ）×（１＋３．０Ｍｏ）・・・式（１）
ただし、式中の元素記号には、各元素の含有率（質量％）を代入する。
The third means is, by mass%, C: 0.25 to 0.40%, Si: 0.05 to 0.30%, Mn: 1.00 to 1.50%, P: 0.030% or less. , S: 0.030% or less, Cr: 1.50 to 3.00%, Mo: 0.05 to 0.50%, Al: 0.020 to 0.050%, N: 0.0100 to 0. 0200%, the balance being Fe and unavoidable impurities,
The value of A in the following formula (1) is 10 or more and 20 or less,
Further, when subjected to quenching and tempering from a heating temperature of 30 ° C. to 100 ° C. higher than the austenitizing temperature, the quenching hardness is 45 HRC or more, which is an alloy steel for machine structural use.
A = 0.5C × (1 + 0.7Si) × (1 + 3.6Mn) × (1 + 2.2Cr) × (1 + 3.0Mo) Formula (1)
However, the content (% by mass) of each element is substituted for the element symbol in the formula.
第４の手段は第３の手段に記載の化学成分に加えて、質量％で、Ｎｂ：０．０２〜０．０４％、Ｔｉ：０．００５〜０．０３０％のうち一種または二種を含有し、ＮｂとＴｉの質量％の合計値は０．００５≦（Ｎｂ＋Ｔｉ）≦０．０５０を満足するものであって、残部がＦｅおよび不可避的不純物からなり、
以下の式（１）のＡの値が１０以上２０以下であって、
さらにオーステナイト化温度より３０℃〜１００℃高い加熱温度から焼入焼戻し処理した場合、焼入硬さが４５ＨＲＣ以上となっていることを特徴とする機械構造用合金鋼である。
Ａ＝０．５Ｃ×（１＋０．７Ｓｉ）×（１＋３．６Ｍｎ）×（１＋２．２Ｃｒ）×（１＋３．０Ｍｏ）・・・式（１）
ただし、式中の元素記号には、各元素の含有率（質量％）を代入する。
The fourth means includes one or two of Nb: 0.02 to 0.04% and Ti: 0.005 to 0.030% by mass% in addition to the chemical components described in the third means. Contained, and the total value of the mass% of Nb and Ti satisfies 0.005 ≦ (Nb + Ti) ≦ 0.050, and the balance consists of Fe and inevitable impurities.
The value of A in the following formula (1) is 10 or more and 20 or less,
Further, when subjected to quenching and tempering from a heating temperature of 30 ° C. to 100 ° C. higher than the austenitizing temperature, the quenching hardness is 45 HRC or more, which is an alloy steel for machine structural use.
A = 0.5C × (1 + 0.7Si) × (1 + 3.6Mn) × (1 + 2.2Cr) × (1 + 3.0Mo) Formula (1)
However, the content (% by mass) of each element is substituted for the element symbol in the formula.
本発明は、Ｓｉの低減によって粒界炭化物を抑制し、またＡｌ、Ｎの添加によりピンニング粒子であるＡｌＮを析出させることによって結晶粒粗大化を抑止して靱性を改善し、Ｃ、Ｍｎ、Ｃｒ、Ｍｏを適切に添加することにより、焼入れ時に鋼材の中心部まで焼入れ硬化させることができる。そこで、硬さと靱性のバランスに優れた土木建設機械用部材に好適な鋼を得ることができる。 The present invention suppresses grain boundary carbides by reducing Si, and suppresses coarsening of grains by adding Al and N to precipitate AlN, which is pinning particles, to improve toughness. , Mo can be quenched and hardened to the center of the steel material during quenching. Therefore, it is possible to obtain steel suitable for members of civil engineering construction machines having an excellent balance between hardness and toughness.
また、本発明の機械構造用合金鋼は、さらにオーステナイト化温度の３０〜１００℃の高さの加熱温度から焼入焼戻し処理をした際には、鋼材の中心の硬さが４５ＨＲＣ以上となっている。さらにシャルピー衝撃試験により測定した衝撃値が３５Ｊ／ｃｍ2を確保しやすくなっている。そこで、硬さと靱性のバランスに優れた土木建設機械用部材に好適な鋼を得ることができる。 Further, when the alloy steel for machine structural use of the present invention is further quenched and tempered from a heating temperature of 30 to 100 ° C., which is an austenitizing temperature, the hardness of the center of the steel material becomes 45 HRC or more. I have. Further, it is easy to secure an impact value of 35 J / cm 2 measured by a Charpy impact test. Therefore, it is possible to obtain steel suitable for members of civil engineering construction machines having an excellent balance between hardness and toughness.
以下、本発明の機械構造用合金鋼における各成分組成を決定した理由と、式（１）によりＡ値を特定する理由、ならびに焼入温度、焼入焼戻し後の鋼材中心部の硬さの限定理由を説明する。なお、化学成分の％は質量％である。 Hereinafter, the reasons for determining the respective component compositions in the alloy steel for machine structural use of the present invention, the reason for specifying the A value by the formula (1), the quenching temperature, and the limitation of the hardness of the central portion of the steel material after quenching and tempering. Explain why. In addition,% of a chemical component is a mass%.
Ｃ：０．２５〜０．４０％
Ｃは、焼入れ時のマトリックス強度を向上させ、焼入性、耐摩耗性を向上させるのに有効な元素である。Ｃが０．２５％以下では十分な硬度が確保できないため、Ｃは０．２５％以上とする。一方、Ｃが０．４０％を超えると靱性を大きく低下させるため、Ｃは０．４０％以下とする。そこで、Ｃは０．２５〜０．４０％とする。
また、より高い靱性を確保するため、好ましくは、Ｃは０．２５〜０．３５％とする。
C: 0.25 to 0.40%
C is an element effective for improving the matrix strength during quenching and improving the hardenability and wear resistance. If C is 0.25% or less, sufficient hardness cannot be secured, so C is set to 0.25% or more. On the other hand, if C exceeds 0.40%, the toughness is greatly reduced, so C is set to 0.40% or less. Therefore, C is set to 0.25 to 0.40%.
Further, in order to ensure higher toughness, C is preferably set to 0.25 to 0.35%.
Ｓｉ：０．０５〜０．３０％
Ｓｉは、鋼の脱酸に必要であるとともに、焼入性の向上に影響する元素である。焼入れ性を向上させるためには、Ｓｉは０．０５％以上必要である。他方、Ｓｉが０．３０％を超えると粒界炭化物の生成を促進し、靱性を低下させるため、Ｓｉは０．３０％以下とする。そこで、Ｓｉは０．０５〜０．３０％である。
Si: 0.05 to 0.30%
Si is an element necessary for deoxidation of steel and affects the improvement of hardenability. In order to improve hardenability, Si needs to be 0.05% or more. On the other hand, if Si exceeds 0.30%, the formation of grain boundary carbides is promoted, and the toughness is reduced. Therefore, the content of Si is set to 0.30% or less. Therefore, Si is 0.05 to 0.30%.
Ｍｎ：１．００〜１．５０％
Ｍｎは、焼入性の向上、焼戻軟化抵抗性の向上に有効な元素であり、そのためにはＭｎが１．００％以上必要である。一方、Ｍｎが１．５０％を超えると結晶粒界に偏析し、靱性を低下させるため、Ｍｎは１．５０％以下とする。そこで、Ｍｎは１．００〜１．５０％である。
Mn: 1.00 to 1.50%
Mn is an element effective for improving hardenability and tempering softening resistance. For that purpose, Mn must be 1.00% or more. On the other hand, if Mn exceeds 1.50%, it segregates at the crystal grain boundaries and lowers toughness, so Mn is set to 1.50% or less. Therefore, Mn is 1.00 to 1.50%.
Ｐ：０．０３０％以下
Ｐは、結晶粒界に偏析し、靱性を低下させる元素である。そこで、Ｐは０．０３０％以下とする。
P: 0.030% or less P is an element that segregates at crystal grain boundaries and lowers toughness. Therefore, P is set to 0.030% or less.
Ｓ：０．０３０％以下
Ｓは、靱性の低下を招く元素である。そこで、Ｓは０．０３０％以下とする。
S: 0.030% or less S is an element that causes a decrease in toughness. Therefore, S is set to 0.030% or less.
Ｃｒ：１．５０〜３．００％
Ｃｒは、焼入性、焼戻軟化抵抗性を増加させ、耐摩耗性を向上させるのに有効な元素である。Ｃｒが１．５０％以下では鋼材の中心部まで焼入れ硬化させることができないため、Ｃｒは１．５０％以上とする。一方、Ｃｒが３．００％を超えると靱性の低下、焼入性過剰による製造性の低下を招くため、Ｃｒは３．００％以下とする。そこで、Ｃｒは１．５０〜３．００％である。
Cr: 1.50 to 3.00%
Cr is an element effective for increasing hardenability and temper softening resistance and improving wear resistance. If the Cr content is 1.50% or less, it is not possible to harden and harden the center of the steel material, so the Cr content is 1.50% or more. On the other hand, if the Cr content exceeds 3.00%, the toughness is reduced, and the productivity is reduced due to excessive hardenability. Therefore, the Cr content is set to 3.00% or less. Therefore, Cr is 1.50 to 3.00%.
Ｍｏ：０．０５〜０．５０％
Ｍｏは、焼入性、焼戻軟化抵抗性の向上に有効な元素である。焼入性と焼戻軟化抵抗性の向上のためにはＭｏが０．０５％以上必要である。一方、Ｍｏが０．５０％を超えると鋼材の成分偏析を助長するため、Ｍｏは０．５０％以下とする。そこで、Ｍｏは０．０５〜０．５０％である。
Mo: 0.05 to 0.50%
Mo is an element effective for improving hardenability and tempering softening resistance. Mo is required to be 0.05% or more to improve hardenability and temper softening resistance. On the other hand, when Mo exceeds 0.50%, the segregation of components of the steel material is promoted, so that Mo is set to 0.50% or less. Therefore, Mo is 0.05 to 0.50%.
Ａｌ：０．０２０〜０．０５０％
Ａｌは、鋼中でＡｌＮを形成し、ピンニング粒子としてオーステナイト粒径の粗大化を抑制することで靱性の向上に寄与する。靱性の向上のためにはＡｌは０．０２０％以上とする。一方、Ａｌは０．０５０％を超えると窒化物や酸化物が粗大化してしまうので、靱性が低下するとともに製造性が低下することから、Ａｌは０．０５０％以下とする。そこでＡｌは０．０２０〜０．０５０％である。
Al: 0.020 to 0.050%
Al contributes to the improvement of toughness by forming AlN in steel and suppressing coarsening of austenite particle size as pinning particles. To improve toughness, Al is made 0.020% or more. On the other hand, if Al exceeds 0.050%, nitrides and oxides become coarse, so that toughness is reduced and manufacturability is reduced. Therefore, Al is set to 0.050% or less. Therefore, Al is 0.020 to 0.050%.
Ｎ：０．０１００〜０．０２００％
Ｎは、鋼中でＡｌＮを形成し、オーステナイト粒径の粗大化を抑制する元素であり、そのためにはＮが０．０１００％以上必要である。一方、Ｎは０．０２００％を超えると窒化物が粗大化し、靱性が低下するため、Ｎは０．０２００％以下とする。そこで、は０．０１００〜０．０２００％である。
N: 0.0100 to 0.0200%
N is an element that forms AlN in the steel and suppresses the coarsening of the austenite grain size. For that purpose, N must be 0.0100% or more. On the other hand, if N exceeds 0.0200%, the nitride coarsens and the toughness decreases, so N is set to 0.0200% or less. Therefore, is 0.0100 to 0.0200%.
さらに、本発明の機械構造用合金鋼には、選択的成分としてＴｉ、Ｎｂのうち１種類または２種類を、以下に説明する数値範囲で含有させてもよい。 Further, the alloy steel for machine structural use of the present invention may contain one or two of Ti and Nb as selective components in a numerical range described below.
Ｔｉ：０．００５〜０．０３０％
Ｔｉは、ＴｉはＡｌと同様にオーステナイト粒径の粗大化を抑制するのに有効な元素である。そのためにはＴｉは０．００５％以上必要である。一方、Ｔｉは０．０３０％を超えると窒化物の粗大化により靱性が低下するため、Ｔｉは０．０３０％以下とする。そこで、Ｔｉ：０．００５〜０．０３０％である。
Ti: 0.005 to 0.030%
Ti, like Al, is an element effective in suppressing the austenite grain size from becoming coarse. For that, 0.005% or more of Ti is required. On the other hand, if the content of Ti exceeds 0.030%, the toughness decreases due to coarsening of the nitride, so the content of Ti is set to 0.030% or less. Therefore, Ti: 0.005 to 0.030%.
Ｎｂ：０．０２〜０．０４％
Ｎｂは、鋼中でＮｂＣを形成し、オーステナイト粒径の粗大化を抑制することで靱性の向上に寄与する。そのためにはＮｂは０．０２％以上とする。一方、Ｎｂが０．０４％を超えると粗大なＮｂＣが析出し、靱性が低下するため、Ｎｂは０．０４％以下とする。
Nb: 0.02 to 0.04%
Nb forms NbC in steel and contributes to improvement of toughness by suppressing coarsening of austenite grain size. Therefore, Nb is set to 0.02% or more. On the other hand, if Nb exceeds 0.04%, coarse NbC precipitates and the toughness decreases, so Nb is set to 0.04% or less.
ＮｂとＴｉの質量％の合計値 Ｎｂ＋Ｔｉ：０．００５〜０．０５０％
ＮｂとＴｉの質量％の合計値は０．０５０％で効果が飽和するため、ＮｂとＴｉの質量％の合計値は、０．００５〜０．０５０％とする。すなわち、合計値は、０．００５≦（Ｎｂ＋Ｔｉ）≦０．０５０を満足するものである。
Total value of mass% of Nb and Ti Nb + Ti: 0.005 to 0.050%
Since the effect saturates when the total value of the mass% of Nb and Ti is 0.050%, the total value of the mass% of Nb and Ti is 0.005 to 0.050%. That is, the total value satisfies 0.005 ≦ (Nb + Ti) ≦ 0.050.
式（１）について
Ａ＝０．５Ｃ×（１＋０．７Ｓｉ）×（１＋３．６Ｍｎ）×（１＋２．２Ｃｒ）×（１＋３．０Ｍｏ）・・・式（１）
式（１）で示すＡ値が１０以上２０以下であること
式（１）のＡ値は、値が増大する程、鋼材の焼入性は向上する指標であり、式（１）で勘案する成分元素と、Ａ値の算定のための各成分元素の計数は、焼入れ性の観点から設定している。なお、Ａ値は、各元素部分に、該当の元素の成分組成を質量％で表した数値が代入されることで算出して求める。
Ａ値は、鋼材の中心部まで焼入れ硬化することにより、耐摩耗性が向上することから、大型の部材にも十分適用することができるようになる。そこで、φ２００未満の鋼材径に対し中心部まで焼入れ硬化できるように、Ａ値は１０以上とする。
一方、Ａ値が２０以上であると焼入性が過剰となることから、コストの増加、製造性の低下を招くこととなるので、Ａ値は２０以下とする。そこで、本発明における式（１）で示すＡ値は１０以上２０以下の範囲とする。
A = 0.5C × (1 + 0.7Si) × (1 + 3.6Mn) × (1 + 2.2Cr) × (1 + 3.0Mo) for Expression (1) Expression (1)
A value represented by the formula (1) is 10 or more and 20 or less
The A value in the formula (1) is an index for improving the hardenability of the steel as the value increases, and the component elements considered in the formula (1) and the count of each component element for calculating the A value Is set from the viewpoint of hardenability. Note that the A value is calculated and obtained by substituting a numerical value representing the component composition of the corresponding element in mass% into each element portion.
The A value can be sufficiently applied to a large member because the wear resistance is improved by quenching and hardening to the center of the steel material. Therefore, the A value is set to 10 or more so that the steel material having a diameter of less than φ200 can be quenched and hardened to the center.
On the other hand, when the A value is 20 or more, the hardenability becomes excessive, which leads to an increase in cost and a decrease in productivity, so the A value is set to 20 or less. Therefore, the A value represented by the formula (1) in the present invention is set to be in a range of 10 or more and 20 or less.
オーステナイト化温度より３０℃〜１００℃高い加熱温度から焼入焼戻し処理をした際に焼入れされた部材の硬さが４５ＨＲＣ以上となっていること
焼入温度が低いと、十分に鋼材を焼入れ硬化させることができないため、焼入温度は鋼材のオーステナイト化温度より３０℃以上高いものとする。もっとも、焼入温度が過度に高すぎると結晶粒の粗大化が生じて靱性の低下を招くことがあるので、焼入温度は鋼材のオーステナイト化温度より高いとしても１００℃以下の高さとする。そこで、焼入処理のために部材を加熱する温度は、オーステナイト化温度より３０℃〜１００℃高い加熱温度とする。
そして、上記範囲の加熱温度から焼入焼戻処理された機械構造用合金鋼の部材は、焼入焼戻し後の鋼材の中心部硬さが４５ＨＲＣ以上となる。
When the quenching and tempering treatment is performed from a heating temperature 30 ° C. to 100 ° C. higher than the austenitizing temperature, the hardness of the quenched member is 45 HRC or more. Therefore, the quenching temperature is 30 ° C. or more higher than the austenitizing temperature of the steel material. However, if the quenching temperature is too high, the crystal grains may be coarsened and the toughness may be reduced. Therefore, the quenching temperature is set to 100 ° C. or less even if it is higher than the austenitizing temperature of the steel material. Therefore, the temperature at which the member is heated for the quenching treatment is set to a heating temperature 30 ° C. to 100 ° C. higher than the austenitizing temperature.
Then, the hardness of the central part of the steel material after the quenching and tempering of the member of the alloy steel for machine structure subjected to the quenching and tempering treatment from the heating temperature in the above range is 45 HRC or more.
すると、本発明の鋼は、例えばオーステナイト化温度より３０℃〜１００℃高い加熱温度から焼入焼戻した後の鋼材は、鋼材中心部の硬さが４５ＨＲＣ以上であり、なおかつ３５Ｊ／ｃｍ2以上の衝撃値を確保することができるので、硬さと靱性の双方がバランス良く優れたものとなる。 Then, the steel of the present invention, for example, after quenching and tempering from a heating temperature of 30 ° C. to 100 ° C. higher than the austenitizing temperature, has a hardness at the center of the steel of 45 HRC or more and 35 J / cm 2 or more. Since an impact value can be secured, both hardness and toughness are excellent in a well-balanced manner.
さらに、Ｃが０．２５〜０．３５％であるときには、オーステナイト化温度より３０℃〜１００℃高い加熱温度で焼入焼戻した後の鋼材は、鋼材中心部の硬さが４５ＨＲＣ以上であり、なおかつ４０Ｊ／ｃｍ2以上の衝撃値を確保することができるので、硬さとより高い靱性の双方をバランス良く得ることができる。 Further, when C is 0.25 to 0.35%, the steel material after quenching and tempering at a heating temperature 30 ° C. to 100 ° C. higher than the austenitizing temperature has a hardness at the center of the steel material of 45 HRC or more, In addition, since an impact value of 40 J / cm 2 or more can be secured, both hardness and higher toughness can be obtained in a well-balanced manner.
以下に、本発明の実施例を示す。まず、表１に示すＮｏ．１〜１０の実施例鋼およびＮｏ．１１〜２１の比較例鋼のそれぞれの化学成分からなる鋼を１００ｋｇ真空溶解炉で溶製した。 Hereinafter, examples of the present invention will be described. First, No. 1 shown in Table 1 was used. Example steels Nos. 1 to 10 and Nos. Steels composed of the respective chemical components of Comparative Examples 11 to 21 were melted in a 100 kg vacuum melting furnace.
得られた鋼部材を試験片へと加工し、靱性についてはＪＩＳ Ｚ ２２４２に基づいたシャルピー衝撃試験を用いて評価した。また、耐摩耗性については直径１６０ｍｍの鋼材を焼入焼戻ししたときの鋼材中心部の硬さをＪＩＳ Ｚ ２２４５に基づいたロックウェル硬度測定にて評価した。 The obtained steel member was processed into a test piece, and the toughness was evaluated using a Charpy impact test based on JIS Z 2242. As for wear resistance, the hardness of the center of the steel material when the steel material having a diameter of 160 mm was quenched and tempered was evaluated by Rockwell hardness measurement based on JIS Z 2245.
まず表１に示す鋼を１２００℃で直径１６０ｍｍに鍛伸した後、８７０℃で１時間保持後空冷の焼ならしを行った。その後、焼入れ処理として８７０℃に加熱して１００〜２００分保持後に水冷し室温まで冷却した後、２１０℃に６０〜９０分保持後に６０℃に油冷にて室温まで冷却して焼戻しを行い棒鋼を得た。得られた棒鋼について、靱性、耐摩耗性を評価した。
すなわち、上記の条件で製造、熱処理を行った棒鋼について、中心の位置より、それぞれＪＩＳ ３号 ２ｍｍ Ｖノッチシャルピー衝撃試験片を採取し、ＪＩＳ Ｚ ２２４２に準拠してシャルピー衝撃試験を行った。
First, the steel shown in Table 1 was forged to a diameter of 160 mm at 1200 ° C., held at 870 ° C. for 1 hour, and then air-cooled. Thereafter, as a quenching treatment, the steel bar is heated to 870 ° C., kept for 100 to 200 minutes, cooled with water and cooled to room temperature, and then kept at 210 ° C. for 60 to 90 minutes, cooled to room temperature with oil cooling to 60 ° C., and tempered. I got The obtained steel bars were evaluated for toughness and wear resistance.
That is, JIS No. 3 2 mm V-notch Charpy impact test specimens were taken from the center position of the steel bars manufactured and heat-treated under the above conditions, and subjected to a Charpy impact test in accordance with JIS Z2242.
また、上記の条件で製造、熱処理を行った棒鋼について、棒鋼の長さの中心位置（１／２Ｌ位置）より、直径１６０ｍｍ×長さ１５ｍｍを硬さ測定用試験片として採取し、ＪＩＳ Ｚ ２２４５に準拠し、鋼材の直径１６０ｍｍの中心部の硬さをロックウェル硬度測定機にて測定した。
表２にシャルピー衝撃試験、硬さ測定の結果と、焼入性の指標として式（１）のＡ値を示す。
Further, with respect to the steel bar manufactured and heat-treated under the above conditions, a diameter 160 mm × length 15 mm was sampled as a hardness measurement test piece from the center position (１ ／ L position) of the length of the steel bar, and JIS Z 2245 The hardness at the center of the steel material having a diameter of 160 mm was measured by a Rockwell hardness tester in accordance with JIS.
Table 2 shows the results of the Charpy impact test and the hardness measurement, and the A value of the formula (1) as an index of hardenability.
表２に示した通り、本発明に従う実施例鋼（Ｎｏ．１〜１０）は、中心部硬さが４５ＨＲＣ以上、シャルピー衝撃値が３５Ｊ／ｃｍ2以上を満たしており、硬さと靱性のバランスに優れる鋼であることが確認された。 As shown in Table 2, the steels of Examples (Nos. 1 to 10) according to the present invention have a center hardness of 45 HRC or more, a Charpy impact value of 35 J / cm 2 or more, and a balance between hardness and toughness. It was confirmed that the steel was excellent.
また、さらにＣの成分範囲を０．２５〜０．３５％としたときには、すなわち実施例鋼Ｎｏ．１、３、４、６、７、１０は、鋼材中心部の硬さが４５ＨＲＣ以上であり、なおかつシャルピー試験の衝撃値が４０Ｊ／ｃｍ2以上となったことから、硬さと靱性にさらに優れる鋼が得られることが確認された。 Further, when the component range of C is set to 0.25 to 0.35%, that is, in the case of Example Steel No. 1, 3, 4, 6, 7, 10 are steels having a hardness of 45 HRC or more at the center of the steel material and an impact value of 40 J / cm 2 or more in the Charpy test. Was obtained.
これに対し、式（１）で示すＡ値が１０未満である比較例鋼Ｎｏ．１１、１６、１８、１９、２１は、鋼材中心部の硬さが４５ＨＲＣを下回っており、焼入性の不足から鋼材の中心部まで焼入れ硬化していないことが確認された。
他方、式（１）で示すＡ値が２０以上である比較例鋼Ｎｏ．１２、１３では、合金元素量が多いことから焼入性が過剰となっており、製造性の低下、コストの増加が懸念されるとともに、靱性の低下も認められた。
また、Ｓｉ量が多い比較例鋼Ｎｏ．１４、１５では、靱性の低下が認められた。
さらに、Ｃ量が多い比較例鋼Ｎｏ．１７、２０、２２、２３では、Ｃ量が過剰であることから靱性の低下を招いており、シャルピー衝撃値が３５Ｊ／ｃｍ2に満たず、靱性に劣ることが分かった。
On the other hand, the comparative example steel No. in which the A value represented by the formula (1) is less than 10 was used. In Nos. 11, 16, 18, 19, and 21, the hardness at the center of the steel material was lower than 45 HRC, and it was confirmed that hardening was not performed to the center of the steel material due to insufficient hardenability.
On the other hand, the comparative example steel No. having the A value represented by the formula (1) of 20 or more. In Nos. 12 and 13, the hardenability was excessive due to the large amount of alloying elements, and there was a concern about a decrease in productivity and an increase in cost, and a decrease in toughness was also recognized.
In addition, Comparative Example Steel No. In Nos. 14 and 15, a decrease in toughness was observed.
Furthermore, the comparative example steel No. In 17, 20, 22, and 23, since the C content was excessive, the toughness was reduced, and the Charpy impact value was less than 35 J / cm 2 , indicating that the toughness was poor.
Claims (4)
Ａ＝０．５Ｃ×（１＋０．７Ｓｉ）×（１＋３．６Ｍｎ）×（１＋２．２Ｃｒ）×（１＋３．０Ｍｏ）・・・式（１）
ただし、式中の元素記号には、各元素の含有率（質量％）を代入する。 In mass%, C: 0.25 to 0.40%, Si: 0.05 to 0.30%, Mn: 1.00 to 1.50%, P: 0.030% or less, S: 0.030 % Or less, Cr: 1.50 to 3.00%, Mo: 0.05 to 0.50%, Al: 0.020 to 0.050%, N: 0.0100 to 0.0200%, An alloy steel for machine structural use, wherein the balance consists of Fe and unavoidable impurities, and the value of A in the following formula (1) is 10 or more and 20 or less.
A = 0.5C × (1 + 0.7Si) × (1 + 3.6Mn) × (1 + 2.2Cr) × (1 + 3.0Mo) Formula (1)
However, the content (% by mass) of each element is substituted for the element symbol in the formula.
Ａ＝０．５Ｃ×（１＋０．７Ｓｉ）×（１＋３．６Ｍｎ）×（１＋２．２Ｃｒ）×（１＋３．０Ｍｏ）・・・式（１）
ただし、式中の元素記号には、各元素の含有率（質量％）を代入する。 In addition to the chemical components according to claim 1, one or two of Nb: 0.02 to 0.04% and Ti: 0.005 to 0.030% by mass% are contained, and Nb and Ti are contained. The total value of mass% satisfies 0.005 ≦ (Nb + Ti) ≦ 0.050, and the balance consists of Fe and unavoidable impurities, and the value of A in the following formula (1) is 10 or more and 20 or less. Alloy steel for machine structural use characterized by the following.
A = 0.5C × (1 + 0.7Si) × (1 + 3.6Mn) × (1 + 2.2Cr) × (1 + 3.0Mo) Formula (1)
However, the content (% by mass) of each element is substituted for the element symbol in the formula.
以下の式（１）のＡの値が１０以上２０以下であって、
さらにオーステナイト化温度より３０℃〜１００℃高い加熱温度から焼入焼戻し処理した場合、焼入硬さが４５ＨＲＣ以上となっていることを特徴とする機械構造用合金鋼。
Ａ＝０．５Ｃ×（１＋０．７Ｓｉ）×（１＋３．６Ｍｎ）×（１＋２．２Ｃｒ）×（１＋３．０Ｍｏ）・・・式（１）
ただし、式中の元素記号には、各元素の含有率（質量％）を代入する。 In mass%, C: 0.25 to 0.40%, Si: 0.05 to 0.30%, Mn: 1.00 to 1.50%, P: 0.030% or less, S: 0.030 % Or less, Cr: 1.50 to 3.00%, Mo: 0.05 to 0.50%, Al: 0.020 to 0.050%, N: 0.0100 to 0.0200%, The balance consists of Fe and inevitable impurities,
The value of A in the following formula (1) is 10 or more and 20 or less,
An alloy steel for machine structural use, wherein quenching hardness is 45 HRC or more when quenching and tempering is performed at a heating temperature 30 ° C. to 100 ° C. higher than the austenitizing temperature.
A = 0.5C × (1 + 0.7Si) × (1 + 3.6Mn) × (1 + 2.2Cr) × (1 + 3.0Mo) Formula (1)
However, the content (% by mass) of each element is substituted for the element symbol in the formula.
以下の式（１）のＡの値が１０以上２０以下であって、
さらにオーステナイト化温度より３０℃〜１００℃高い加熱温度から焼入焼戻し処理した場合、焼入硬さが４５ＨＲＣ以上となっていることを特徴とする機械構造用合金鋼。
Ａ＝０．５Ｃ×（１＋０．７Ｓｉ）×（１＋３．６Ｍｎ）×（１＋２．２Ｃｒ）×（１＋３．０Ｍｏ）・・・式（１）
ただし、式中の元素記号には、各元素の含有率（質量％）を代入する。 In addition to the chemical components according to claim 3, one or two of Nb: 0.02 to 0.04% and Ti: 0.005 to 0.030% by mass% are contained, and Nb and Ti are contained. Satisfies 0.005 ≦ (Nb + Ti) ≦ 0.050, the balance being Fe and unavoidable impurities,
The value of A in the following formula (1) is 10 or more and 20 or less,
An alloy steel for machine structural use, wherein quenching hardness is 45 HRC or more when quenching and tempering is performed at a heating temperature 30 ° C. to 100 ° C. higher than the austenitizing temperature.
A = 0.5C × (1 + 0.7Si) × (1 + 3.6Mn) × (1 + 2.2Cr) × (1 + 3.0Mo) Formula (1)
However, the content (% by mass) of each element is substituted for the element symbol in the formula.
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Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH07173541A (en) * | 1993-12-17 | 1995-07-11 | Sumitomo Metal Ind Ltd | Production of high strength electric resistance welded pipe for machine structural use |
| JP2005344149A (en) * | 2004-06-01 | 2005-12-15 | Kobe Steel Ltd | High strength steel for large-sized steel forging, and crankshaft |
| JP2010180455A (en) * | 2009-02-06 | 2010-08-19 | Sumitomo Metal Ind Ltd | Case-hardening steel |
| JP2010222697A (en) * | 2008-08-29 | 2010-10-07 | Sanyo Special Steel Co Ltd | Steel for machine structural use having excellent toughness |
| JP2011246798A (en) * | 2009-06-24 | 2011-12-08 | Jfe Steel Corp | High-strength seamless steel tube for oil well with excellent resistance to sulfide stress cracking, and method for producing the same |
| JP2012007221A (en) * | 2010-06-28 | 2012-01-12 | Daido Steel Co Ltd | Method for manufacturing steel for plastic molding die |
| JP2013010983A (en) * | 2011-06-28 | 2013-01-17 | Sanyo Special Steel Co Ltd | Steel for plastic molding mold |
| WO2017038879A1 (en) * | 2015-09-02 | 2017-03-09 | 大同特殊鋼株式会社 | Steel for molds and molding tool |
-
2018
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Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH07173541A (en) * | 1993-12-17 | 1995-07-11 | Sumitomo Metal Ind Ltd | Production of high strength electric resistance welded pipe for machine structural use |
| JP2005344149A (en) * | 2004-06-01 | 2005-12-15 | Kobe Steel Ltd | High strength steel for large-sized steel forging, and crankshaft |
| JP2010222697A (en) * | 2008-08-29 | 2010-10-07 | Sanyo Special Steel Co Ltd | Steel for machine structural use having excellent toughness |
| JP2010180455A (en) * | 2009-02-06 | 2010-08-19 | Sumitomo Metal Ind Ltd | Case-hardening steel |
| JP2011246798A (en) * | 2009-06-24 | 2011-12-08 | Jfe Steel Corp | High-strength seamless steel tube for oil well with excellent resistance to sulfide stress cracking, and method for producing the same |
| JP2012007221A (en) * | 2010-06-28 | 2012-01-12 | Daido Steel Co Ltd | Method for manufacturing steel for plastic molding die |
| JP2013010983A (en) * | 2011-06-28 | 2013-01-17 | Sanyo Special Steel Co Ltd | Steel for plastic molding mold |
| WO2017038879A1 (en) * | 2015-09-02 | 2017-03-09 | 大同特殊鋼株式会社 | Steel for molds and molding tool |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP7544489B2 (en) | 2020-02-17 | 2024-09-03 | 山陽特殊製鋼株式会社 | Alloy steel for machine structures with an excellent balance of hardness and toughness |
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