JP3544460B2 - Method for producing hardened steel with excellent fatigue properties - Google Patents
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Description
【発明の属する技術分野】
本発明は、浸炭あるいは浸炭窒化処理を行って使用されるはだ焼き鋼で、転動疲労寿命および回転曲げ疲労寿命の優れたはだ焼き鋼に関するものである。
【０００２】
【従来の技術】
従来、機械構造用鋼で転動疲労寿命や回転曲げ疲労寿命を要する鋼は、対炭素鋼を浸炭あるいは浸炭窒化して使用している場合が多い。疲労強度の向上には、マトリックスの強化と結晶粒の安定化が必要であるが、浸炭あるいは浸炭窒化処理は高温で長時間熱処理されるため、結晶粒が粗大化しやすく、また、結晶粒が粗大化した場合、疲労強度が著しく劣化する。そのため、例えば、特開昭５６−１１６８５７号公報に記載の発明など、従来からＡｌやＮｂの炭窒化物で結晶粒の安定化を試みたものは多くあるが、結晶粒を粗大化させない量のみの添加量にとどまり、マトリックスの強化まで試みたものはなかった。
【０００３】
【発明が解決しようとする課題】
そこで本発明では、従来の浸炭あるいは浸炭窒化用鋼にＴｉを０．１０〜０．３０％と過剰に添加し、適切な温度で圧延を行うことにより、鋼中に微細なＴｉ炭化物を多数分散析出させ、結晶粒を安定化するとともに、転動疲労寿命および回転曲げ疲労強度を向上させたはだ焼き鋼の製造方法である。
【０００４】
【課題を解決するための手段】
上記の課題を解決するためのこの発明の手段は、請求項１の発明では、質量％で、Ｃ：０．１０〜．４５％、Ｓｉ：０．０５〜０．５０％、Ｍｎ：０．２〜１．５％、Ｔｉ：０．１０〜０．３０％、Ｎ：＜０．０１％を含有し、残部Ｆｅ及び不可避不純物からなる鋼材を、鋳片から鋼片に圧延する際、１２５０℃〜１４００℃の温度範囲に加熱して熱間圧延を行い、一旦室温まで冷却した後、ついで、この鋼片をＡｃ3〜１０５０℃の温度範囲で加熱して圧延することを特徴とする転動疲労寿命および回転曲げ疲労寿命に優れたはだ焼き鋼の製造方法である。
【０００５】
請求項２の発明では、質量％で、Ｃ：０．１０〜．４５％、Ｓｉ：０．０５〜０．５０％、Ｍｎ：０．２〜１．５％、Ｔｉ：０．１０〜０．３０％、Ｎ：＜０．０１％を含有し、さらに選択的に、Ｃｒ：０．１５〜２．０％、Ｍｏ：０．０３〜１．５％、Ｎｉ：０．１〜３．０％の中から少なくとも１種以上を含み、残部Ｆｅ及び不可避不純物からなる鋼材を、鋳片から鋼片に圧延する際、１２５０℃〜１４００℃の温度範囲に加熱して熱間圧延を行い、一旦室温まで冷却した後、ついで、この鋼片をＡｃ3〜１０５０℃の温度範囲で加熱して圧延することを特徴とする転動疲労寿命および回転曲げ疲労寿命に優れたはだ焼き鋼の製造方法である。
【０００６】
請求項３の発明では、質量％で、Ｃ：０．１０〜．４５％、Ｓｉ：０．０５〜０．５０％、Ｍｎ：０．２〜１．５％、Ｔｉ：０．１０〜０．３０％、Ｎ：＜０．０１％、Ｂ：０．０００５〜０．００５０％を含み、残部Ｆｅ及び不可避不純物からなる鋼材を、鋳片から鋼片に圧延する際、１２５０℃〜１４００℃の温度範囲に加熱して熱間圧延を行い、一旦室温まで冷却した後、ついで、この鋼片をＡｃ3〜１０５０℃の温度範囲で加熱して圧延することを特徴とする転動疲労寿命および回転曲げ疲労寿命に優れたはだ焼き鋼の製造方法。
【０００７】
請求項４の発明では、質量％で、Ｃ：０．１０〜．４５％、Ｓｉ：０．０５〜０．５０％、Ｍｎ：０．２〜１．５％、Ｔｉ：０．１０〜０．３０％、Ｎ：＜０．０１％、Ｂ：０．０００５〜０．００５０％を含有し、さらに選択的に、Ｃｒ：０．１５〜２．０％、Ｍｏ：０．０３〜１．５％、Ｎｉ：０．１〜３．０％の少なくとも１種以上を含み、残部Ｆｅ及び不可避不純物からなる鋼材を、鋳片から鋼片に圧延する際、１２５０℃〜１４００℃の温度範囲に加熱して熱間圧延を行い、一旦室温まで冷却した後、ついで、この鋼片をＡｃ3〜１０５０℃の温度範囲で加熱して圧延することを特徴とする転動疲労寿命および回転曲げ疲労寿命に優れたはだ焼き鋼の製造方法である。
【０００８】
本発明は上記のように、従来の機械構造用鋼にＴｉを０．１０〜０．３０％添加し、１２５０℃〜１４００℃の温度範囲に加熱して鋳片を鋼片に圧延し、ついで、Ａｃ3〜１０５０℃の温度範囲に加熱して製品圧延を行なうことにより、圧延ままで微細に分散析出したＴｉ炭化物が得られ、この微細に分散析出したＴｉ炭化物が結晶粒成長の阻止およびマトリックスの強化として働き、結晶粒の粗大化が起こらず、かつ転動疲労寿命および回転曲げ疲労強度に優れたはだ焼き鋼が得られる。
【０００９】
本発明の組成割合の限定理由を述べる。
Ｃは、焼入れ性を著しく向上させる元素であり、部品の機械的性質に対してはだ焼き鋼として要求される強さや衝撃値を得るためには最低０．１０％必要である。また、Ｃ量が増加すると強度が増すが、Ｃが０．４５％を超えると加工性が著しく低下するため、Ｃ量は、Ｃ：０．１０〜０．４５％とする。
【００１０】
Ｓｉは、焼入れ性に効果のある元素であるが、０．０５％未満では脱酸効果が十分でなく、０．５０％を超えると加工性が著しく低下するため、０．０５〜０．５０％とする。
【００１１】
Ｍｎは、鋼の焼入れ性に効果のある元素であるが、０．２％未満では焼入れ性が不足し、１．５％を超えると加工性が低下するため、０．２〜１．５％とする。
【００１２】
Ｔｉは、鋼中にＴｉ炭化物の形で微細分散し、転動疲労寿命を向上させ、また焼入れ時の結晶粒の粗大化を抑制する元素であるが、０．１０％以下では、その効果が少なく、また、０．３０％を超えると加工性が低下するため、含有量を０．１０〜０．３０％とする。
【００１３】
Ｎは、本発明鋼では必要ないばかりか、Ｎ量が増えると疲労強度に有害なＴｉ窒化物が増えるため、Ｎ：＜０．０１％とする。
【００１４】
Ｂは、極く微量の添加によって、鋼の焼入性を著しく向上させる元素であるが、０．０００５％未満ではその効果は十分ではなく、０．００５％を超えると、逆に焼入性を低下させ靭性を劣化させる。そのため、含有量を０．０００５〜０．００５％とする。
【００１５】
Ｃｒ、Ｍｏ、Ｎｉは、焼入れ性、靱性、疲労寿命の向上に効果のある元素で選択的に１種以上添加できるが、少なすぎると効果がなく、多すぎると効果は飽和する。そこで、Ｃｒ：０．１５〜２．０％、Ｍｏ：０．０３〜１．５％、Ｎｉ：０．１〜３．０％とする。
【００１６】
本発明による製造方法は、上記化学成分を含有する鋼を対象とし、鋳片から鋼片に圧延する際、１２５０℃〜１４００℃の温度範囲に加熱して熱間圧延を行い、ついでこの鋼片をＡｃ3〜１０５０℃の温度範囲で加熱して圧延するものである。ここで、鋳片を１２５０℃〜１４００℃の温度範囲に加熱して、鋼片に圧延するのは、一旦、Ｔｉ炭化物を完全に固溶さすためであり、１２５０℃未満の加熱ではＴｉ炭化物の固溶が不十分であり、また加熱炉の耐用性から１４００℃以下とする。次に、鋼片をＡｃ3〜１０５０℃の温度範囲で加熱して圧延するのは、圧延段階で微細なＴｉ炭化物を鋼中に多数分散析出させるためで、１０５０℃を超える温度に加熱すると微細なＴｉ炭化物が得られず、またＡｃ3 未満の加熱温度では、フェライトや炭化物が残り、圧延後の組織において均一な組織が得られないためである。
【００１７】
【発明の実施の形態】
表１に示す化学成分組成の供試鋼（比較鋼１〜４、発明鋼１〜４）を真空溶解炉で溶製し、鋳片を１６７ｍｍφの鋼片に圧延して、ついで、６５ｍｍφおよび２０ｍｍφに圧延し、焼きならし後、スラスト型寿命試験片（６０ｍｍφ×４．５ｍｍＴ）および回転曲げ疲労試験片（８．０ｍｍ×１７ｍｍＬ）に加工し、試験片に供した。
【００１８】
また、本発明の実施の形態の鋼組成を表１の発明鋼１〜４に示す。発明鋼１はＳ２０ＣにＴｉを０．１５９％添加したものであり、発明鋼２は発明鋼１にＣｒとＭｏを添加したものである。発明鋼３は、発明鋼１のＳｉ、Ｍｎを低減し、Ｂを添加したものであり、発明鋼４は発明鋼１にＣｒを添加したものである。これらの鋼を、まず、１２５０℃〜１４００℃の温度に加熱し圧延を行い、ついでＡｃ３ 〜１０５０℃の温度に加熱して、圧延を行い素材として用いる。
【００１９】
【実施例】
まず、転動疲労寿命試験の試験条件を示す。表１に示す種々の成分組成材を６５ｍｍφ棒鋼に圧延し、６０ｍｍφ×４．５ｍｍＴに加工し、９３０℃×６時間で浸炭焼入れ焼き戻し処理を行い、スラスト型転動寿命試験を行った。試験条件は最大ヘルツ応力５．２４ＧＰａ、応力繰返し数１８００ｃｐｍで累積破損確率１０％（Ｌ１０）の繰返し数の比で評価した。
【００２０】
次に、回転曲げ疲労試験の試験条件を示す。表１に示す種々の成分組成材を２０ｍｍφ棒鋼に圧延し、平行部８．０ｍｍφ×１７ｍｍＬの平滑試験片に加工し、９３０℃×６時間で浸炭焼入れ焼き戻し処理をを行い、回転曲げ疲労試験片を行った。試験条件は回転数３０００ｒｐｍで１０７回疲労時間強度（疲労限強度）の比で評価した。
【００２１】
表１に今回実験に用いた鋼の成分を示す。比較鋼１はＳ２０Ｃ鋼であり、比較鋼２は、比較鋼１にＣｒとＭｏを含有させた鋼である。比較例３は比較例１のＳｉ、Ｍｎを低減し、Ｂを添加したものであり、比較例４は、比較例３にＣｒを含有させた鋼である。
【００２２】
これに対し、発明鋼１〜４は比較鋼に対して、Ｔｉを添加した鋼で、本発明の実施の形態を示す実施例である。
【００２３】
【表１】
次に、表１に示す鋼を表２に示す温度範囲に加熱して、熱間圧延を行い素材を製造し、試験片を作成して、転動疲労試験機および回転曲げ疲労試験機を用いて試験を行い、累積破損率１０％（Ｌ１０）の応力繰返し回数における比較例１（Ｓ２０Ｃ鋼）の寿命を１、あるいは、１０７ 回疲労時間強度における比較例１の疲労強度を１とし、これに対する寿命比及び疲労強度比で評価を行った。
【００２５】
その結果を表２に示す。表２より、比較鋼１に対しＴｉを０．１５９％添加した発明鋼１は転動疲労寿命および回転曲げ疲労寿命が向上していることがわかる。しかしながらＮｏ．２およびＮｏ．３は圧延温度が不適切なので、その効果はあまり大きくなく、圧延温度が適切なＮｏ．４が最も効果が大きい。同様に、比較鋼２に対しＴｉを０．１５５％添加した発明鋼２は転動疲労寿命および回転曲げ疲労寿命が向上しており、特に圧延温度が最も適切な、Ｎｏ．８が最も効果が大きい。発明鋼７および発明鋼８も同様である。
【００２６】
【表２】
以上の試験の結果、Ｔｉを添加し適切な加熱条件で圧延することによって、転動疲労寿命および回転曲げ疲労寿命が向上していることがわかる。また、実施例は比較例に対して浸炭時の結晶粒も安定しており、Ｔｉ炭化物の微細な析出物が確認された。
【００２８】
【発明の効果】
以上説明した通り、本発明による鋼は、Ｔｉを０．０１〜０．３０％添加し、適切な加熱温度で圧延することにすることにより、転動疲労寿命および回転曲げ疲労寿命が向上するという優れた効果を有するものである。さらにＢを極く微量添加して鋼の焼入性を著しく向上させている。まはさらにＣｒ、Ｍｏ、Ｎｉを選択的に添加してさらに焼入れ性、靱性、疲労寿命を向上させている。TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to a case hardened steel used after being subjected to carburizing or carbonitriding treatment and having excellent rolling fatigue life and rotational bending fatigue life.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, many steels for machine structural use which require rolling fatigue life or rotating bending fatigue life are often used by carburizing or carbonitriding carbon steel. In order to improve the fatigue strength, it is necessary to strengthen the matrix and stabilize the crystal grains.However, since the carburizing or carbonitriding treatment is performed at a high temperature for a long time, the crystal grains are likely to be coarsened. , Fatigue strength is significantly degraded. Therefore, for example, there have been many attempts to stabilize crystal grains with carbon nitrides of Al and Nb, such as the invention described in Japanese Patent Application Laid-Open No. 56-116857 , but only an amount that does not cause the crystal grains to be coarsened. , And no attempt was made to strengthen the matrix.
[0003]
[Problems to be solved by the invention]
Therefore, in the present invention, a large number of fine Ti carbides are dispersed in steel by adding an excessive amount of Ti to 0.10 to 0.30% to conventional carburizing or carbonitriding steel and performing rolling at an appropriate temperature. This is a method for producing a case hardened steel that precipitates and stabilizes crystal grains, and also has improved rolling fatigue life and rotational bending fatigue strength.
[0004]
[Means for Solving the Problems]
The means of the invention to solve the above problems, the invention of claim 1, in mass%, C: 0.10 to. 45%, Si: 0.05 to 0.50%, Mn: 0.2 to 1.5%, Ti: 0.10 to 0.30%, N: <0.01%, with the balance Fe and When rolling a steel material consisting of unavoidable impurities from a slab to a slab, it is heated to a temperature range of 1250 ° C. to 1400 ° C. to perform hot rolling, and once cooled to room temperature, the slab is then subjected to Ac 3. A method for producing a case hardened steel having excellent rolling fatigue life and rotational bending fatigue life, characterized by being heated and rolled in a temperature range of -1050 ° C.
[0005]
In the invention of claim 2, in mass%, C: 0.10 to. 45%, Si: 0.05-0.50%, Mn: 0.2-1.5%, Ti: 0.10-0.30%, N: <0.01%, more selective Contains at least one or more of Cr: 0.15 to 2.0%, Mo: 0.03 to 1.5%, and Ni: 0.1 to 3.0%, with the balance being Fe and inevitable impurities. When the resulting steel material is rolled from a slab to a slab, it is heated to a temperature range of 1250 ° C. to 1400 ° C. to perform hot rolling, and once cooled to room temperature, and then the slab is Ac 3 to 1050 ° C. A method for producing a case hardened steel having excellent rolling fatigue life and rotational bending fatigue life characterized by being heated and rolled in the above temperature range.
[0006]
In the invention of claim 3, in mass%, C: 0.10 to. 45%, Si: 0.05 to 0.50%, Mn: 0.2 to 1.5%, Ti: 0.10 to 0.30%, N: <0.01%, B: 0.0005 to When rolling a steel material containing 0.0050%, the balance being Fe and unavoidable impurities, from a slab to a slab, it was heated to a temperature range of 1250 ° C. to 1400 ° C., hot-rolled, and once cooled to room temperature. Then, a method for producing a case-hardened steel having excellent rolling fatigue life and rotational bending fatigue life, wherein the steel slab is heated and rolled in a temperature range of Ac 3 to 1050 ° C.
[0007]
In the invention of claim 4, in mass%, C: 0.10 to. 45%, Si: 0.05 to 0.50%, Mn: 0.2 to 1.5%, Ti: 0.10 to 0.30%, N: <0.01%, B: 0.0005 to 0.0050%, and optionally, at least one or more of Cr: 0.15 to 2.0%, Mo: 0.03 to 1.5%, and Ni: 0.1 to 3.0%. Including, the steel material consisting of the balance Fe and unavoidable impurities, when rolling from cast slabs to steel slabs, hot rolling is performed by heating to a temperature range of 1250 ° C to 1400 ° C, and once cooled to room temperature, A method for producing a case hardened steel having excellent rolling fatigue life and rotational bending fatigue life, characterized in that the steel slab is heated and rolled in a temperature range of Ac 3 to 1050 ° C.
[0008]
As described above, the present invention adds 0.10 to 0.30% of Ti to a conventional steel for machine structural use, heats the steel to a temperature range of 1250 ° C. to 1400 ° C., and rolls the slab into a steel slab. , Ac 3 to 1050 ° C., the product is rolled to obtain a finely dispersed and precipitated Ti carbide as rolled, and the finely dispersed and precipitated Ti carbide prevents crystal grain growth and matrix A hardened steel which does not cause coarsening of crystal grains and has excellent rolling fatigue life and rotational bending fatigue strength is obtained.
[0009]
The reasons for limiting the composition ratio of the present invention will be described.
C is an element which remarkably improves the hardenability, and at least 0.10% is required for obtaining the strength and impact value required for hardened steel with respect to the mechanical properties of parts. Further, the strength increases as the C content increases, but when C exceeds 0.45%, the workability remarkably deteriorates. Therefore, the C content is C: 0.10 to 0.45%.
[0010]
Si is an element having an effect on hardenability, but if it is less than 0.05%, the deoxidizing effect is not sufficient, and if it exceeds 0.50%, workability is remarkably reduced. %.
[0011]
Mn is an element effective for the hardenability of steel, but if it is less than 0.2%, the hardenability is insufficient, and if it exceeds 1.5%, the workability is reduced. And
[0012]
Ti is an element that is finely dispersed in steel in the form of Ti carbides, improves rolling fatigue life, and suppresses the coarsening of crystal grains during quenching. If the content is small, and if it exceeds 0.30%, the workability decreases, so the content is made 0.10 to 0.30%.
[0013]
N is not necessary in the steel of the present invention, and when the amount of N increases, Ti nitride harmful to fatigue strength increases.
[0014]
B is an element that remarkably improves the hardenability of steel by adding a very small amount. However, if the content is less than 0.0005%, the effect is not sufficient. And toughness is deteriorated. Therefore, the content is made 0.0005 to 0.005%.
[0015]
Cr, Mo, and Ni are elements that are effective in improving the hardenability, toughness, and fatigue life, and one or more of them can be selectively added. Therefore, Cr: 0.15 to 2.0%, Mo: 0.03 to 1.5%, and Ni: 0.1 to 3.0%.
[0016]
The production method according to the present invention is directed to a steel containing the above-mentioned chemical component, and when rolling from a cast slab to a steel slab, is heated to a temperature range of 1250 ° C. to 1400 ° C. to perform hot rolling. Is rolled by heating in a temperature range of Ac 3 to 1050 ° C. Here, by heating the slab to a temperature range of 1250 ° C. to 1400 ° C., for rolling steel pieces, once is because refer complete solid solution of Ti carbide, the Ti carbide is heated below 1250 ° C. The solid solution is insufficient, and the temperature is set to 1400 ° C. or less from the durability of the heating furnace. Next, the slab is heated and rolled in a temperature range of Ac 3 to 1050 ° C. in order to cause a large number of fine Ti carbides to be dispersed and precipitated in the steel in the rolling stage. Ti carbide cannot be obtained, and Ac 3 If the heating temperature is lower than this , ferrite and carbide remain, and a uniform structure cannot be obtained in the structure after rolling.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Test steels (comparative steels 1-4, invention steels 1-4) having the chemical composition shown in Table 1 were melted in a vacuum melting furnace, and the slabs were rolled into 167 mmφ steel slabs, followed by 65 mmφ and 20 mmφ. After normalizing, the test piece was processed into a thrust type life test specimen (60 mmφ × 4.5 mmT) and a rotating bending fatigue test specimen (8.0 mm × 17 mmL), and provided as test specimens.
[0018]
The steel compositions of the embodiment of the present invention are shown in Invention Steels 1 to 4 in Table 1. Invention Steel 1 is obtained by adding 0.159% of Ti to S20C, and Invention Steel 2 is obtained by adding Cr and Mo to Invention Steel 1. Invention Steel 3 is obtained by reducing Si and Mn of Invention Steel 1 and adding B, and Invention Steel 4 is obtained by adding Cr to Invention Steel 1. These steels are first heated to a temperature of 1250 ° C. to 1400 ° C. and rolled, and then heated to a temperature of Ac 3 to 1050 ° C. and rolled to use as a material.
[0019]
【Example】
First, test conditions of the rolling fatigue life test will be described. The various component compositions shown in Table 1 were rolled into 65 mmφ steel bars, processed to 60 mmφ × 4.5 mmT, carburized, quenched and tempered at 930 ° C. × 6 hours, and a thrust rolling life test was performed. The test conditions were evaluated based on the ratio of the number of repetitions at a maximum Hertz stress of 5.24 GPa, a stress repetition rate of 1800 cpm, and a cumulative failure probability of 10% (L 10 ).
[0020]
Next, test conditions of the rotating bending fatigue test will be described. The various component compositions shown in Table 1 were rolled into 20mmφ steel bars, processed into parallel test pieces of 8.0mmφ × 17mmL, carburized, quenched and tempered at 930 ° C. for 6 hours, and subjected to a rotary bending fatigue test. Pieces went. The test conditions were evaluated by the ratio of fatigue time strength (fatigue limit strength) 107 times at a rotation speed of 3000 rpm.
[0021]
Table 1 shows the components of the steel used in this experiment. Comparative steel 1 is S20C steel, and comparative steel 2 is steel in which Cr and Mo are added to comparative steel 1. Comparative Example 3 is a steel in which Si and Mn of Comparative Example 1 are reduced and B is added, and Comparative Example 4 is a steel in which Comparative Example 3 contains Cr.
[0022]
On the other hand, inventive steels 1 to 4 are steels in which Ti is added to comparative steels, and are examples showing the embodiment of the present invention.
[0023]
[Table 1]
Next, the steel shown in Table 1 was heated to the temperature range shown in Table 2, hot-rolled to produce a material, a test piece was prepared, and a rolling fatigue tester and a rotary bending fatigue tester were used. were tested Te, 1 life Comparative example stress repeat count of the cumulative failure rate 10% (L 10) 1 (S20C steel) or, the fatigue strength of Comparative example 1 in 10 7 times fatigue time strength and 1, Evaluation was made based on the life ratio and the fatigue strength ratio.
[0025]
Table 2 shows the results. From Table 2, it can be seen that the inventive steel 1 in which 0.159% of Ti is added to the comparative steel 1 has improved rolling fatigue life and rotational bending fatigue life. However, no. 2 and No. No. 3 has an inadequate rolling temperature because the rolling temperature is inappropriate. 4 is the most effective. Similarly, Invention Steel 2 in which 0.155% of Ti is added to Comparative Steel 2 has improved rolling fatigue life and rotational bending fatigue life. 8 is the most effective. The same applies to invention steel 7 and invention steel 8.
[0026]
[Table 2]
As a result of the above test, it can be understood that rolling fatigue under rolling conditions and rolling fatigue life are improved by adding Ti and rolling under appropriate heating conditions. Further, in the examples, the crystal grains at the time of carburizing were more stable than the comparative examples, and fine precipitates of Ti carbide were confirmed.
[0028]
【The invention's effect】
As described above, the steel according to the present invention improves the rolling fatigue life and the rotating bending fatigue life by adding 0.01 to 0.30% of Ti and rolling at an appropriate heating temperature. It has excellent effects. Further, a very small amount of B is added to significantly improve the hardenability of the steel. Furthermore, quenching properties, toughness, and fatigue life are further improved by selectively adding Cr, Mo, and Ni.
Claims (4)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP26804097A JP3544460B2 (en) | 1997-09-11 | 1997-09-11 | Method for producing hardened steel with excellent fatigue properties |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP26804097A JP3544460B2 (en) | 1997-09-11 | 1997-09-11 | Method for producing hardened steel with excellent fatigue properties |
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| Publication Number | Publication Date |
|---|---|
| JPH1192824A JPH1192824A (en) | 1999-04-06 |
| JP3544460B2 true JP3544460B2 (en) | 2004-07-21 |
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| US7081174B2 (en) | 2002-04-30 | 2006-07-25 | Sanyo Special Steel Co., Ltd. | Process for producing steel products having improved grain size properties and machinability |
| CN102131945B (en) | 2009-01-16 | 2014-04-16 | 新日铁住金株式会社 | Case hardening steel, carburized component, and method for producing case hardening steel |
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