JP2009057597A - Gear and manufacturing method thereof - Google Patents
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- JP2009057597A JP2009057597A JP2007225631A JP2007225631A JP2009057597A JP 2009057597 A JP2009057597 A JP 2009057597A JP 2007225631 A JP2007225631 A JP 2007225631A JP 2007225631 A JP2007225631 A JP 2007225631A JP 2009057597 A JP2009057597 A JP 2009057597A
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- 238000004519 manufacturing process Methods 0.000 title claims abstract description 19
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 36
- 239000010959 steel Substances 0.000 claims abstract description 36
- 229910001567 cementite Inorganic materials 0.000 claims abstract description 34
- KSOKAHYVTMZFBJ-UHFFFAOYSA-N iron;methane Chemical compound C.[Fe].[Fe].[Fe] KSOKAHYVTMZFBJ-UHFFFAOYSA-N 0.000 claims abstract description 34
- 239000010410 layer Substances 0.000 claims abstract description 25
- 238000000034 method Methods 0.000 claims abstract description 25
- 238000010438 heat treatment Methods 0.000 claims abstract description 21
- 229910052748 manganese Inorganic materials 0.000 claims abstract description 17
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 17
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 16
- 230000008569 process Effects 0.000 claims abstract description 15
- 229910052750 molybdenum Inorganic materials 0.000 claims abstract description 13
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 12
- 239000002344 surface layer Substances 0.000 claims abstract description 7
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 6
- 238000001816 cooling Methods 0.000 claims abstract description 6
- 239000012535 impurity Substances 0.000 claims abstract description 5
- 238000010791 quenching Methods 0.000 claims abstract description 3
- 230000000171 quenching effect Effects 0.000 claims abstract description 3
- 238000005255 carburizing Methods 0.000 claims description 27
- 229910052759 nickel Inorganic materials 0.000 claims description 12
- 239000002245 particle Substances 0.000 claims description 5
- 229910052742 iron Inorganic materials 0.000 claims description 2
- 230000000452 restraining effect Effects 0.000 abstract 1
- 230000000052 comparative effect Effects 0.000 description 12
- 239000007789 gas Substances 0.000 description 12
- 238000010586 diagram Methods 0.000 description 11
- 238000012360 testing method Methods 0.000 description 10
- 239000000654 additive Substances 0.000 description 7
- 230000000996 additive effect Effects 0.000 description 7
- 238000012545 processing Methods 0.000 description 5
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 3
- 239000005977 Ethylene Substances 0.000 description 3
- 229910001566 austenite Inorganic materials 0.000 description 3
- 229910052739 hydrogen Inorganic materials 0.000 description 3
- 239000001257 hydrogen Substances 0.000 description 3
- 238000001556 precipitation Methods 0.000 description 3
- 239000004215 Carbon black (E152) Substances 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 229910052737 gold Inorganic materials 0.000 description 2
- 229930195733 hydrocarbon Natural products 0.000 description 2
- 150000002430 hydrocarbons Chemical class 0.000 description 2
- 229910052697 platinum Inorganic materials 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 229910000658 steel phase Inorganic materials 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 238000013467 fragmentation Methods 0.000 description 1
- 238000006062 fragmentation reaction Methods 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 238000012886 linear function Methods 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000010705 motor oil Substances 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 238000009628 steelmaking Methods 0.000 description 1
- 229910000859 α-Fe Inorganic materials 0.000 description 1
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- Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
- Heat Treatment Of Articles (AREA)
- Gears, Cams (AREA)
Abstract
Description
本発明は、製造に必要な時間が短く、かつ粗大なセメンタイトの残留の抑制及び焼戻し軟化抵抗の向上により耐ピッチング性が向上した歯車及びその製造方法に関する。 The present invention relates to a gear having improved pitching resistance by suppressing the residual coarse cementite and improving temper softening resistance, and a method for manufacturing the same.
建設機械車両の減速機やホイールローダのベベルギアなどに用いられる歯車に求められる特性の一つに、耐ピッチング性すなわち面圧強度の向上がある。耐ピッチング性を向上させる方法として、歯車を浸炭処理して表面に硬化層を形成する方法がある（例えば特許文献１参照）。 One of the characteristics required for gears used in reduction gears for construction machinery vehicles and bevel gears for wheel loaders is improvement in pitting resistance, that is, surface pressure strength. As a method for improving the pitting resistance, there is a method of carburizing a gear to form a hardened layer on the surface (see, for example, Patent Document 1).
図９は、歯車に真空浸炭処理を行う従来の方法を説明するためのチャートであり、図１０（Ａ）〜（Ｄ）は、それぞれ図９のＡ〜Ｄのタイミングにおける鋼の組織を示す模式図である。本図に示す方法では、まず歯車を減圧雰囲気下で加熱する。そしてＡｃ３点以上の所定の温度（本図に示す例では１０００℃）に達した場合、この温度に維持したまま、雰囲気に炭化水素ガスを導入する。これにより、浸炭が行われる。このとき、図１０（Ａ）の模式図に示すように、オーステナイト結晶粒界に粗大なセメンタイトが析出する。 FIG. 9 is a chart for explaining a conventional method for subjecting a gear to a vacuum carburizing process, and FIGS. 10A to 10D are schematic diagrams showing steel structures at timings A to D in FIG. 9, respectively. FIG. In the method shown in the figure, the gear is first heated under a reduced pressure atmosphere. Then, when a predetermined temperature of Ac 3 points or higher (1000 ° C. in the example shown in the figure) is reached, hydrocarbon gas is introduced into the atmosphere while maintaining this temperature. Thereby, carburization is performed. At this time, coarse cementite precipitates at the austenite grain boundaries as shown in the schematic diagram of FIG.
そして一定時間ほど浸炭が行われた後、炭化水素ガスの導入を終了し、かつ歯車を所定の温度に所定時間ほど維持する。これにより、図１０（Ｂ）及び（Ｃ）に示すように、粗大なセメンタイトが徐々に溶解し、そして消滅していく。 Then, after carburizing for a certain time, the introduction of the hydrocarbon gas is finished, and the gear is maintained at a predetermined temperature for a predetermined time. As a result, as shown in FIGS. 10B and 10C, coarse cementite gradually dissolves and disappears.
その後、歯車をＡｒ１点以下に空冷する。次いで歯車を再び加熱し、歯車をＡｃ１点以上の温度で所定時間保持する。これにより、図１０（Ｄ）に示すように、微細な粒状のセメンタイトが分散析出する。 Thereafter, the gear is air-cooled to Ar 1 point or less. Next, the gear is heated again, and the gear is held at a temperature of Ac 1 point or higher for a predetermined time. Thereby, as shown in FIG. 10D, fine granular cementite is dispersed and precipitated.
上記した従来例では、浸炭処理後にセメンタイト分散の為の熱処理を行っても、例えば図１０（Ｃ）に示すように、粗大なセメンタイトが結晶粒界に残留する場合があった。粗大なセメンタイトは応力集中源となり、歯車の耐ピッチング性を低下させてしまう。なお、Ａ１点を跨ぐように歯車の加熱・冷却を複数回繰り返して炭化物を分断する方法も考えられるが、この場合、歯車の製造に必要な時間が長くなってしまう。 In the conventional example described above, even when heat treatment for dispersing cementite is performed after carburizing, coarse cementite may remain at the grain boundaries as shown in FIG. 10C, for example. Coarse cementite becomes a source of stress concentration and reduces the gear pitting resistance. Although considered a method of dividing a plurality of times repeatedly carbide heating and cooling of the gear so as to straddle the point A, in this case, becomes long the time required for the manufacture of gears.
また、使用中の歯車には、すべりによる摩擦熱が加わる為、常温雰囲気で歯車が使用されている場合であっても、歯車の表面は高温になりやすい。このため、歯車の耐ピッチング性を向上させるためには歯車の焼戻し軟化抵抗を向上させる必要がある In addition, since frictional heat due to sliding is applied to the gear in use, the surface of the gear tends to be hot even when the gear is used in a room temperature atmosphere. For this reason, it is necessary to improve the temper softening resistance of the gear in order to improve the pitting resistance of the gear.
本発明は上記のような事情を考慮してなされたものであり、その目的は、製造に必要な時間が短く、かつ粗大なセメンタイトの残留の抑制及び焼戻し軟化抵抗の向上により耐ピッチング性が向上した歯車及びその製造方法を提供することにある。 The present invention has been made in view of the above circumstances, and its purpose is to shorten the time required for production, and to improve the pitting resistance by suppressing the residual coarse cementite and improving the temper softening resistance. An object of the present invention is to provide a gear and a manufacturing method thereof.
上記課題を解決する為、本発明に係る歯車は、質量％で、Ｃ：０．１０〜０．３０％、Ｓｉ：１．０〜１．５％、Ｍｎ：０．２０〜１．５％、Ｃｒ：０．３１％以下、Ｍｏ：０．１〜１．０％、残部がＦｅ及び不可避的不純物からなり、かつ下記（１）式を満たす鋼で形成され、
表層に炭素濃度が１質量％以上の浸炭層が形成され、かつ該浸炭層中のセメンタイトの平均粒径が５μｍ以下であることを特徴とする。
ｗＣｒ≦（１．４２×１０−３ｗＳｉ＋４．１５×１０−４ｗＮｉ−３．４５×１０−４ｗＭｎ−１．０６×１０−４ｗＭｏ−９．１２×１０−４）Ｔ−１．３７ｗＳｉ＋０．３８６ｗＮｉ＋０．２２１ｗＭｎ−０．１４７ｗＭｏ＋１．３５…（１）
ただし、ｗＣｒ、ｗＳｉ、ｗＮｉ、ｗＭｎ、及びｗＭｏはそれぞれＣｒ、Ｓｉ、Ｎｉ、Ｍｎ、及びＭｏの質量％、Ｔ＝浸炭処理を行う処理温度（Ｋ）。
In order to solve the above-mentioned problems, the gear according to the present invention is, in mass%, C: 0.10 to 0.30%, Si: 1.0 to 1.5%, Mn: 0.20 to 1.5%. Cr: 0.31% or less, Mo: 0.1-1.0%, the balance is formed of steel consisting of Fe and inevitable impurities, and satisfying the following formula (1),
A carburized layer having a carbon concentration of 1% by mass or more is formed on the surface layer, and an average particle diameter of cementite in the carburized layer is 5 μm or less.
w Cr ≦ (1.42 × 10 -3 w Si + 4.15 × 10 -4 w Ni -3.45 × 10 -4 w Mn -1.06 × 10 -4 w Mo -9.12 × 10 -4 ) T-1.37w Si + 0.386w Ni + 0.221w Mn -0.147w Mo +1.35 (1)
However, w Cr, w Si, w Ni, w Mn, and w Mo, respectively Cr, Si, Ni, Mn, and Mo wt%, T = the carburizing treatment is performed treating temperature (K).
また本発明に係る歯車の製造方法は、質量％で、Ｃ：０．１０〜０．３０％、Ｓｉ：１．０〜１．５％、Ｍｎ：０．２０〜１．５％、Ｃｒ：０．３１％以下、Ｍｏ：０．１〜１．０％、残部がＦｅ及び不可避的不純物からなり、かつ下記（１）式を満たす鋼からなる歯車を製造する工程と、
前記歯車をＡｃ３点以上に加熱して真空浸炭処理を行うことにより、該歯車の表層に炭素濃度が１質量％以上の浸炭層を形成し、その後前記歯車をＡｒ１以下の温度に冷却する工程と、
前記歯車をＡｃ１点以上に加熱して所定時間保持することにより、前記浸炭層中に、平均粒径が５μｍ以下のセメンタイトを形成する工程と、
前記歯車を冷却して焼入れする工程と、
を具備する。
ｗＣｒ≦（１．４２×１０−３ｗＳｉ＋４．１５×１０−４ｗＮｉ−３．４５×１０−４ｗＭｎ−１．０６×１０−４ｗＭｏ−９．１２×１０−４）Ｔ−１．３７ｗＳｉ＋０．３８６ｗＮｉ＋０．２２１ｗＭｎ−０．１４７ｗＭｏ＋１．３５…（１）
ただし、ｗＣｒ、ｗＳｉ、ｗＮｉ、ｗＭｎ、及びｗＭｏはそれぞれＣｒ、Ｓｉ、Ｎｉ、Ｍｎ、及びＭｏの質量％、Ｔ＝浸炭処理を行う処理温度（Ｋ）。
Moreover, the manufacturing method of the gear which concerns on this invention is the mass%, C: 0.10-0.30%, Si: 1.0-1.5%, Mn: 0.20-1.5%, Cr: 0.31% or less, Mo: 0.1 to 1.0%, the process of manufacturing a gear made of steel that consists of Fe and inevitable impurities, and satisfies the following formula (1):
The gear is heated to Ac 3 points or higher and vacuum carburized to form a carburized layer having a carbon concentration of 1% by mass or more on the surface layer of the gear, and then the gear is cooled to a temperature of Ar 1 or lower. Process,
The step of forming cementite having an average particle diameter of 5 μm or less in the carburized layer by heating the gear to Ac 1 point or more and holding for a predetermined time;
Cooling and quenching the gear;
It comprises.
w Cr ≦ (1.42 × 10 -3 w Si + 4.15 × 10 -4 w Ni -3.45 × 10 -4 w Mn -1.06 × 10 -4 w Mo -9.12 × 10 -4 ) T-1.37w Si + 0.386w Ni + 0.221w Mn -0.147w Mo +1.35 (1)
However, w Cr, w Si, w Ni, w Mn, and w Mo, respectively Cr, Si, Ni, Mn, and Mo wt%, T = the carburizing treatment is performed treating temperature (K).
前記浸炭層を形成する工程において、前記歯車の表層に前記浸炭層を形成した後、セメンタイトを分断化させるための繰り返し熱処理を行わずに前記歯車をＡｒ１以下の温度に冷却することも可能である。 In the step of forming the carburized layer, after the carburized layer is formed on the surface layer of the gear, it is also possible to cool the gear to a temperature of Ar1 or lower without performing repeated heat treatment for dividing cementite. .
以下、図面を参照して本発明の実施形態に係る歯車について説明する。この歯車は、例えば建設機械車両の減速機やホイールローダのベベルギアなどに用いられる。以下、質量％を単に％と表示する。本発明者は、真空浸炭時の熱処理条件において粗大なセメンタイトが生成せず、微細なセメンタイトが分散することにより耐ピッチング性が高く、かつ焼戻し軟化抵抗が高い歯車を開発する為、鋭意検討を行った。 Hereinafter, a gear according to an embodiment of the present invention will be described with reference to the drawings. This gear is used, for example, for a reduction gear of a construction machine vehicle or a bevel gear of a wheel loader. Hereinafter, the mass% is simply expressed as%. The present inventor has conducted extensive studies to develop gears that do not generate coarse cementite under the heat treatment conditions during vacuum carburization, and have high pitting resistance and high temper softening resistance by dispersing fine cementite. It was.
まず、焼戻し軟化抵抗を高くするために、歯車を構成する鋼への添加元素としてＳｉに着目した。Ｓｉを添加することにより、焼戻し軟化抵抗は上昇する。焼戻し軟化抵抗を十分得るためには、Ｓｉを１％以上鋼に添加する必要がある。一方、Ｓｉを過剰に添加すると被削性が劣化する為、１．５％を上限とした。 First, in order to increase the temper softening resistance, attention was focused on Si as an additive element to the steel constituting the gear. By adding Si, the temper softening resistance increases. In order to obtain sufficient temper softening resistance, it is necessary to add 1% or more of Si to the steel. On the other hand, if Si is added excessively, machinability deteriorates, so 1.5% was made the upper limit.
またＳｉは、フェライト生成元素である為、Ｓｉを添加することにより鋼のＡ３点は上昇する。これを補うためには、オーステナイト生成元素を鋼に添加する必要がある。オーステナイト生成元素としては、Ｃ，Ｎ，Ｃｕ，Ａｕ，Ｐｔ，Ｍｎ，Ｎｉなどがある。これらのうち、Ｃは硬さを著しく上昇させて機械加工性を劣化させる。また、Ｎは製鋼工程において特殊な設備が必要になり、コストが高くなる。またＣｕは赤熱脆性を引き起こす。またＡｕ，Ｐｔは高価である。以上のことから、本発明ではＭｎ，Ｎｉを添加することにより、Ａ３点の上昇を抑制することにした。 The Si, since a ferrite forming element, the A 3 point of the steel increased by adding Si. In order to compensate for this, it is necessary to add austenite-forming elements to the steel. Examples of austenite generating elements include C, N, Cu, Au, Pt, Mn, and Ni. Of these, C significantly increases the hardness and degrades the machinability. Further, N requires special equipment in the steel making process, and the cost becomes high. Cu also causes red hot brittleness. Au and Pt are expensive. From the above, in the present invention by adding Mn, the Ni, and to suppress an increase in A 3 points.
Ａ３点の上昇を抑制するためには、Ｍｎを０．２％以上添加する必要がある。また、Ｍｎは焼入性を向上させ、歯車に必要な内部強度を与える元素でもある。ただしＭｎを過剰に添加すると被削性が劣化する為、上限を１．５％とした。Ａ３点の上昇を抑制するために不足する分は、Ｎｉで補った。Ｎｉの添加量は、例えば次式（１）で定められる。
Ａｅ３（℃）＝９１０−２０３Ｃ（質量％）０．５＋４４．７Ｓｉ（質量％）−１５．２Ｎｉ（質量％）−３０Ｍｎ（質量％）＋３１．５Ｍｏ（質量％）＋１１Ｃｒ（質量％）…（１）
A In order to suppress the increase of 3 points, it is necessary to add 0.2% or more of Mn. Mn is also an element that improves hardenability and provides the internal strength necessary for the gear. However, if Mn is added excessively, the machinability deteriorates, so the upper limit was made 1.5%. A Insufficient amount to suppress the increase of 3 points was compensated with Ni. The amount of Ni added is determined by the following equation (1), for example.
Ae 3 (° C.) = 910-203C (mass%) 0.5 + 44.7 Si (mass%) − 15.2 Ni (mass%) − 30Mn (mass%) + 31.5 Mo (mass%) + 11Cr (mass%) (1)
なお、上記した添加元素のほかに、本発明では、以下の理由によりＣｒ及びＭｏを鋼に添加することにした。 In addition to the additive elements described above, in the present invention, Cr and Mo are added to the steel for the following reason.
Ｃｒは、焼入性を向上させるために必要な元素である。しかし、過剰に添加すると、後述するように浸炭処理中にセメンタイトが生成しやすくなるため、上限を０．３１％とした。 Cr is an element necessary for improving hardenability. However, if added in excess, cementite is likely to be generated during the carburizing treatment as will be described later, so the upper limit was made 0.31%.
Ｍｏは、焼入性を向上させ、歯車に必要な内部強度を与える元素である。この効果を得るためには、Ｍｏを０．１％以上添加する必要がある。一方、Ｍｏを過剰に添加すると被削性が劣化する為、上限を１．０％とした。 Mo is an element that improves hardenability and provides the internal strength necessary for the gear. In order to acquire this effect, it is necessary to add Mo 0.1% or more. On the other hand, if Mo is added excessively, machinability deteriorates, so the upper limit was made 1.0%.
次に、製造工程数を少なくする方法を検討した。真空浸炭時の熱処理条件においてセメンタイトが生成しない場合、セメンタイト分断化の為の繰り返し熱処理を行う必要が無くなり、歯車の製造工程数が少なくなる。本発明者はこの点に着目し、上記した添加元素を含有する鋼において、真空浸炭時の熱処理条件においてセメンタイトを生成させない方法を検討した。図１〜図４の各図は、真空浸炭時（すなわち炭素活量ａｃ＝１）において、セメンタイト析出の有無に及ぼす合金元素の影響を示す図である。具体的には、図１は、Ｃｒ濃度を横軸にしてＳｉ濃度を縦軸にした場合の、９００℃，９５０℃，１０００℃における鋼の相を示す図である。図２は、Ｃｒ濃度を横軸にしてＮｉ濃度を縦軸にした場合の、９００℃，９５０℃，１０００℃における鋼の相を示す図である。図３は、Ｃｒ濃度を横軸にしてＭｎ濃度を縦軸にした場合の、９００℃，９５０℃，１０００℃における鋼の相を示す図である。図４は、Ｃｒ濃度を横軸にしてＭｏ濃度を縦軸にした場合の、９００℃，９５０℃，１０００℃における鋼の相を示す図である。 Next, a method for reducing the number of manufacturing steps was examined. If cementite is not generated under the heat treatment conditions during vacuum carburization, there is no need to perform repeated heat treatment for cementite fragmentation, and the number of gear manufacturing steps is reduced. The present inventor paid attention to this point and studied a method in which cementite was not generated under the heat treatment conditions during vacuum carburization in the steel containing the above-described additive elements. 1 to 4 are diagrams showing the influence of alloy elements on the presence or absence of cementite precipitation during vacuum carburization (that is, carbon activity ac = 1). Specifically, FIG. 1 is a diagram showing steel phases at 900 ° C., 950 ° C., and 1000 ° C. when the Cr concentration is on the horizontal axis and the Si concentration is on the vertical axis. FIG. 2 is a diagram showing steel phases at 900 ° C., 950 ° C., and 1000 ° C. when the Cr concentration is on the horizontal axis and the Ni concentration is on the vertical axis. FIG. 3 is a diagram showing phases of steel at 900 ° C., 950 ° C., and 1000 ° C. when the Cr concentration is on the horizontal axis and the Mn concentration is on the vertical axis. FIG. 4 is a diagram showing phases of steel at 900 ° C., 950 ° C., and 1000 ° C. when the Cr concentration is on the horizontal axis and the Mo concentration is on the vertical axis.
真空浸炭処理中にセメンタイト（θ）が生成するか否かは、添加している合金元素が相対的にオーステナイト（γ）を安定にするか、セメンタイトを安定にするかによって定まる。例えば、ＣｒとＳｉについては図1のようにSi量が増加するほどγ領域が拡大し、Ｃｒ量が増加するほどγ+θ領域が拡大する。 Whether or not cementite (θ) is generated during the vacuum carburizing process depends on whether the alloying element that is added relatively stabilizes austenite (γ) or stabilizes cementite. For example, for Cr and Si, as shown in FIG. 1, the γ region increases as the Si amount increases, and the γ + θ region increases as the Cr amount increases.
添加元素の濃度の範囲が狭い場合、図１に示したγとγ+θの境界線は直線で近似でき、次式（２）のように表すことができる。
ｗＣｒ＝ａＳｉｗＳｉ＋ｂ …（２）
ここで、ａＳｉ、ｂは定数である。
When the concentration range of the additive element is narrow, the boundary line between γ and γ + θ shown in FIG. 1 can be approximated by a straight line and can be expressed as the following equation (2).
w Cr = a Si w Si + b ... (2)
Here, a Si and b are constants.
ａＳｉは、狭い温度範囲では次式（３）に示すように、温度（Ｋ）の1次関数として表すことができる。
ａＳｉ＝ｐＳｉＴ＋ｑＳｉ …（３）
そして図１において、境界線の左側の領域では真空浸炭中にはθが生成せず、この領域が本発明においてねらいとする領域である。
a Si can be expressed as a linear function of temperature (K) as shown in the following equation (3) in a narrow temperature range.
a Si = p Si T + q Si (3)
In FIG. 1, θ is not generated during vacuum carburization in the region on the left side of the boundary line, and this region is a region aimed at in the present invention.
また図２、図３、及び図４に示すように、Ｎｉ、Ｍｎ、及びＭｏも、Ｓｉの場合と同様に、γ、θそれぞれの安定度を上記式（２）及び（３）と同様の式を用いて、Ｃｒとの相対値として表すことができる。Ｓｉ、Ｎｉ、Ｍｎ、及びＭｏそれぞれにおける式（３）の係数ｐ，ｑは表１のようになる。なお、Crとの比較で表現したのは、Si、Ni、Mn、Mo、Crの中で、Crが最もθを安定にする元素だからである。 As shown in FIGS. 2, 3, and 4, Ni, Mn, and Mo also have the same stability of γ and θ as in the above formulas (2) and (3), as in the case of Si. Using a formula, it can be expressed as a relative value to Cr. Table 1 shows the coefficients p and q of Equation (3) in each of Si, Ni, Mn, and Mo. In addition, the reason for expressing by comparison with Cr is that, among Si, Ni, Mn, Mo, and Cr, Cr is an element that most stabilizes θ.
そして上記した各元素の相互作用は少ない為、複数の元素を鋼に添加した場合におけるγ、θそれぞれの安定度は、Ｃｒとの相対値として、上記式（２）の和として表すことができる。上記式（２）の和において、上記したｂの値は、次式（４）においては１．３５になった。 And since there is little interaction of each above-mentioned element, when a plurality of elements are added to steel, the stability of each of γ and θ can be expressed as the sum of the above formula (2) as a relative value with Cr. . In the sum of the formula (2), the value of b described above is 1.35 in the following formula (4).
また上記したように、図１〜４において境界線の左側の領域では真空浸炭中にはθが生成せず、この領域が本発明においてねらいとする領域である。従って、次式（４）が真空浸炭中にθが生成しない条件になる。
ｗＣｒ≦（１．４２×１０−３ｗＳｉ＋４．１５×１０−４ｗＮｉ−３．４５×１０−４ｗＭｎ−１．０６×１０−４ｗＭｏ−９．１２×１０−４）Ｔ−１．３７ｗＳｉ＋０．３８６ｗＮｉ＋０．２２１ｗＭｎ−０．１４７ｗＭｏ＋１．３５…（４）
In addition, as described above, in the region on the left side of the boundary line in FIGS. 1 to 4, θ is not generated during vacuum carburization, and this region is the region aimed at in the present invention. Therefore, the following equation (4) is a condition that θ is not generated during vacuum carburization.
w Cr ≦ (1.42 × 10 -3 w Si + 4.15 × 10 -4 w Ni -3.45 × 10 -4 w Mn -1.06 × 10 -4 w Mo -9.12 × 10 -4 ) T-1.37w Si + 0.386w Ni + 0.221w Mn -0.147w Mo +1.35 (4)
次に、本発明における歯車の製造方法について説明する。まず上記した条件を満たす成分を有する鋼を溶製し、この鋼を用いて歯車を形成する。次いで、この歯車を、図５に示す処理チャートに従って処理する。 Next, the manufacturing method of the gear in this invention is demonstrated. First, steel having a component that satisfies the above conditions is melted, and a gear is formed using this steel. Next, this gear is processed according to the processing chart shown in FIG.
具体的には、まず歯車を真空浸炭炉内でＡｃ３点以上の温度（例えば１０００℃）まで加熱する。そして雰囲気に浸炭ガスを導入し、歯車を真空浸炭処理して歯車の表層に浸炭層を形成する。浸炭ガスは、例えばエチレンと水素の混合ガスであるが、これに限定されない。 Specifically, the gear is first heated to a temperature of Ac 3 point or higher (for example, 1000 ° C.) in a vacuum carburizing furnace. Then, a carburizing gas is introduced into the atmosphere, and the gear is vacuum carburized to form a carburized layer on the surface of the gear. The carburizing gas is, for example, a mixed gas of ethylene and hydrogen, but is not limited thereto.
一定時間（例えば１１０分）ほど真空浸炭処理を行った後、浸炭ガスの導入を終了して真空浸炭処理を終了する。図６（Ａ）は、真空浸炭処理が終了した直後（図５のＡ点）における歯車の浸炭層の組織を模式的に示す図である。上記した成分を有しているため、真空浸炭処理後の歯車の浸炭層には、セメンタイトが析出していない。そして、Ｎ２ガスを導入し、放冷ファンを駆動させることにより、歯車をＡｒ１点以下に冷却する。 After performing the vacuum carburizing process for a certain time (for example, 110 minutes), the introduction of the carburizing gas is terminated and the vacuum carburizing process is terminated. FIG. 6A is a diagram schematically showing the structure of the carburized layer of the gear immediately after the completion of the vacuum carburizing process (point A in FIG. 5). Since it has the above-mentioned components, cementite is not deposited in the carburized layer of the gear after the vacuum carburizing treatment. Then, N 2 gas was introduced, by driving the cooling fan to cool the gear below 1 point Ar.
次いで歯車を再び加熱してＡｃ１点以上の温度（例えば８５０℃）にして、この温度で一定時間（例えば９０分）熱処理する。図６（Ｂ）は、この熱処理が終了した直後（図５のＢ点）における歯車の浸炭層の組織を模式的に示す図である。熱処理を行うことにより、歯車の浸炭層には、セメンタイトが析出する。このときのセメンタイトの粒径は微細であり、その平均値は５μｍ以下になる。その後、歯車をＭｓ点以下に急冷（例えば油冷）する。 Next, the gear is heated again to a temperature of Ac 1 point or higher (for example, 850 ° C.), and heat treatment is performed at this temperature for a certain time (for example, 90 minutes). FIG. 6B is a diagram schematically showing the structure of the carburized layer of the gear immediately after the end of the heat treatment (point B in FIG. 5). By performing the heat treatment, cementite precipitates in the carburized layer of the gear. The particle size of cementite at this time is fine, and the average value is 5 μm or less. Thereafter, the gear is rapidly cooled (for example, oil-cooled) below the Ms point.
このように、本発明に係る歯車を製造する際には、真空浸炭処理を行った後、セメンタイト分断化のための繰り返し熱処理を行っていない。また、真空浸炭処理後の加熱・冷却は１サイクルのみである。このため、従来と比較して製造に必要な時間が短くなる。 Thus, when manufacturing the gear which concerns on this invention, after performing a vacuum carburizing process, the repeated heat processing for cementite parting is not performed. Moreover, heating / cooling after vacuum carburizing is only one cycle. For this reason, the time required for production is shorter than in the prior art.
表２に示す添加成分を有する実施例１，２に係る鋼を溶製し、これらを図５に示した処理チャートに従って真空浸炭処理した。真空浸炭時の鋼の温度を１０００℃として、真空浸炭処理時間を１１０分とした。またセメンタイト析出の為の熱処理温度を８５０℃として、熱処理時間を９０分とした。浸炭ガスとしては、エチレンと水素の混合ガスを用いた。 Steels according to Examples 1 and 2 having additive components shown in Table 2 were melted and vacuum carburized according to the processing chart shown in FIG. The steel temperature during vacuum carburization was set to 1000 ° C., and the vacuum carburization time was set to 110 minutes. The heat treatment temperature for cementite precipitation was 850 ° C., and the heat treatment time was 90 minutes. As the carburizing gas, a mixed gas of ethylene and hydrogen was used.
また、表２に示す添加成分を有する比較例１，２に係る鋼を、図５に示した処理チャートに従って真空浸炭処理した。真空浸炭時の鋼の温度を１０００℃として、真空浸炭処理時間を７０分として、拡散のための熱処理を３８分とした。またセメンタイト析出の為の熱処理温度を８５０℃として、熱処理時間を６０分とした。浸炭ガスとしては、エチレンと水素の混合ガスを用いた。なお、比較例２に係る鋼は、それぞれＳＣＭ４２０，ＳＮＣＭ２２０である。 Moreover, the steel which concerns on the comparative examples 1 and 2 which has an addition component shown in Table 2 was vacuum-carburized according to the processing chart shown in FIG. The temperature of the steel at the time of vacuum carburizing was 1000 ° C., the time for vacuum carburizing was 70 minutes, and the heat treatment for diffusion was 38 minutes. The heat treatment temperature for cementite precipitation was 850 ° C., and the heat treatment time was 60 minutes. As the carburizing gas, a mixed gas of ethylene and hydrogen was used. In addition, the steel which concerns on the comparative example 2 is SCM420 and SNCM220, respectively.
また、比較例３に係る複数の鋼を、図１１に示した処理チャートに従ってガス浸炭処理した。なお、比較例３に係る鋼の添加成分は、実施例１，２に係る鋼の添加成分と略同じである。 In addition, a plurality of steels according to Comparative Example 3 were subjected to gas carburization treatment according to the treatment chart shown in FIG. In addition, the additive component of the steel which concerns on the comparative example 3 is substantially the same as the additive component of the steel which concerns on Example 1,2.
図７（Ａ）は、実施例１に係る鋼の浸炭層の組織写真であり、図７（Ｂ）は、比較例１に係る鋼の浸炭層の組織写真である。なお、図７（Ｂ）の写真の倍率は、図７（Ａ）と同じである。図７（Ｂ）に示すように、比較例１においては、浸炭処理時に生成した粗大なセメンタイト（炭化物）が残留していた。これに対して、図７（Ａ）に示すように、実施例１においては、粗大なセメンタイトが生成しておらず、セメンタイトは微細粒の状態で分散していた。 FIG. 7 (A) is a structural photograph of the carburized layer of steel according to Example 1, and FIG. 7 (B) is a structural photograph of the carburized layer of steel according to Comparative Example 1. Note that the magnification of the photograph in FIG. 7B is the same as that in FIG. As shown in FIG. 7B, in Comparative Example 1, coarse cementite (carbide) generated during the carburizing process remained. In contrast, as shown in FIG. 7A, in Example 1, coarse cementite was not generated, and cementite was dispersed in the form of fine particles.
次に、実施例１，２に対してローラピッチング試験を行い、さらに比較例３に対してローラピッチング試験を行った。ローラピッチング試験とは、小ローラである試験ローラに対して大ローラである負荷ローラを所定の面圧で押圧し、負荷ローラを所定の回転数で回転させて、ピッチングが発生するまでの回転数を調べる試験である。なお、試験ローラは負荷ローラに対して一定の割合ですべる。 Next, a roller pitching test was performed on Examples 1 and 2, and a roller pitching test was performed on Comparative Example 3. The roller pitching test refers to the number of rotations until pitching occurs by pressing the load roller, which is a large roller, against the test roller, which is a small roller, with a predetermined surface pressure and rotating the load roller at a predetermined number of rotations. It is a test to examine. Note that the test roller slides at a fixed rate relative to the load roller.
図８は、実施例１，２に対してローラピッチング試験を行った結果を、比較例３に対してローラピッチング試験を行って結果と共に示す図であり、横軸にピッチングが発生するまでの回転数、縦軸に面圧（ｋｇ／ｍｍ２）を示している。ローラピッチング試験の条件としては、小ローラの回転速度＝２０００ｒｐｍ、すべり率＝４０％、潤滑剤として８０℃のエンジンオイルＥＯ３０を使用した。また負荷ローラとしては、ＳＣＭ４２０に浸炭処理を行ったものを使用した。なお、比較例３における、ピッチングが発生するまでの回転数と面圧の関係は回帰直線で示している。 FIG. 8 is a diagram showing the result of the roller pitching test performed on Examples 1 and 2 together with the result of the roller pitching test performed on Comparative Example 3, and the rotation until pitching occurs on the horizontal axis. The surface pressure (kg / mm 2) is shown on the number and vertical axis. As conditions for the roller pitching test, a small roller rotational speed = 2000 rpm, a slip rate = 40%, and an engine oil EO30 of 80 ° C. as a lubricant was used. Moreover, as a load roller, what performed carburizing process to SCM420 was used. In addition, in Comparative Example 3, the relationship between the rotational speed until the occurrence of pitching and the surface pressure is shown by a regression line.
本図から、実施例１，２に係る鋼は、耐ピッチング性が比較例３に対して高いことが示された。これは、粗大なセメンタイトの残留が抑制され、かつ焼戻し軟化抵抗が向上したためである。 From this figure, it was shown that the steel according to Examples 1 and 2 has higher pitting resistance than Comparative Example 3. This is because residual coarse cementite is suppressed and temper softening resistance is improved.
以上より、本発明に係る成分を有する鋼を本発明に係る方法で処理することにより、耐ピッチング性が高くなることが示された。 From the above, it was shown that the pitting resistance is enhanced by treating the steel having the component according to the present invention with the method according to the present invention.
尚、本発明は上述した実施形態に限定されるものではなく、本発明の主旨を逸脱しない範囲内で種々変更して実施することが可能である。 Note that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.
Claims (3)
表層に炭素濃度が１質量％以上の浸炭層が形成され、かつ該浸炭層中のセメンタイトの平均粒径が５μｍ以下であることを特徴とする歯車。
ｗＣｒ≦（１．４２×１０−３ｗＳｉ＋４．１５×１０−４ｗＮｉ−３．４５×１０−４ｗＭｎ−１．０６×１０−４ｗＭｏ−９．１２×１０−４）Ｔ−１．３７ｗＳｉ＋０．３８６ｗＮｉ＋０．２２１ｗＭｎ−０．１４７ｗＭｏ＋１．３５…（１）
ただし、ｗＣｒ、ｗＳｉ、ｗＮｉ、ｗＭｎ、及びｗＭｏはそれぞれＣｒ、Ｓｉ、Ｎｉ、Ｍｎ、及びＭｏの質量％、Ｔ＝浸炭処理を行う処理温度（Ｋ）。 In mass%, C: 0.10 to 0.30%, Si: 1.0 to 1.5%, Mn: 0.20 to 1.5%, Cr: 0.31% or less, Mo: 0.1 -1.0%, the balance is made of steel consisting of Fe and inevitable impurities, and satisfying the following formula (1),
A gear having a carburized layer having a carbon concentration of 1% by mass or more formed on a surface layer, and an average particle diameter of cementite in the carburized layer is 5 μm or less.
w Cr ≦ (1.42 × 10 -3 w Si + 4.15 × 10 -4 w Ni -3.45 × 10 -4 w Mn -1.06 × 10 -4 w Mo -9.12 × 10 -4 ) T-1.37w Si + 0.386w Ni + 0.221w Mn -0.147w Mo +1.35 (1)
However, w Cr, w Si, w Ni, w Mn, and w Mo, respectively Cr, Si, Ni, Mn, and Mo wt%, T = the carburizing treatment is performed treating temperature (K).
前記歯車をＡｃ３点以上に加熱して真空浸炭処理を行うことにより、該歯車の表層に炭素濃度が１質量％以上の浸炭層を形成し、その後前記歯車をＡｒ１以下の温度に冷却する工程と、
前記歯車をＡｃ１点以上に加熱して所定時間保持することにより、前記浸炭層中に、平均粒径が５μｍ以下のセメンタイトを形成する工程と、
前記歯車を冷却して焼入れする工程と、
を具備する歯車の製造方法。
ｗＣｒ≦（１．４２×１０−３ｗＳｉ＋４．１５×１０−４ｗＮｉ−３．４５×１０−４ｗＭｎ−１．０６×１０−４ｗＭｏ−９．１２×１０−４）Ｔ−１．３７ｗＳｉ＋０．３８６ｗＮｉ＋０．２２１ｗＭｎ−０．１４７ｗＭｏ＋１．３５…（１）
ただし、ｗＣｒ、ｗＳｉ、ｗＮｉ、ｗＭｎ、及びｗＭｏはそれぞれＣｒ、Ｓｉ、Ｎｉ、Ｍｎ、及びＭｏの質量％、Ｔ＝浸炭処理を行う処理温度（Ｋ）。 In mass%, C: 0.10 to 0.30%, Si: 1.0 to 1.5%, Mn: 0.20 to 1.5%, Cr: 0.31% or less, Mo: 0.1 -1.0%, the process of manufacturing the gearwheel which consists of steel which consists of Fe and an unavoidable impurity, and satisfy | fills following (1) Formula,
The gear is heated to Ac 3 points or higher and vacuum carburized to form a carburized layer having a carbon concentration of 1% by mass or more on the surface layer of the gear, and then the gear is cooled to a temperature of Ar 1 or lower. Process,
The step of forming cementite having an average particle diameter of 5 μm or less in the carburized layer by heating the gear to Ac 1 point or more and holding for a predetermined time;
Cooling and quenching the gear;
The manufacturing method of the gear which comprises this.
w Cr ≦ (1.42 × 10 -3 w Si + 4.15 × 10 -4 w Ni -3.45 × 10 -4 w Mn -1.06 × 10 -4 w Mo -9.12 × 10 -4 ) T-1.37w Si + 0.386w Ni + 0.221w Mn -0.147w Mo +1.35 (1)
However, w Cr, w Si, w Ni, w Mn, and w Mo, respectively Cr, Si, Ni, Mn, and Mo wt%, T = the carburizing treatment is performed treating temperature (K).
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2007225631A JP5191710B2 (en) | 2007-08-31 | 2007-08-31 | Gear and manufacturing method thereof |
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| JP2007225631A JP5191710B2 (en) | 2007-08-31 | 2007-08-31 | Gear and manufacturing method thereof |
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| JP5191710B2 JP5191710B2 (en) | 2013-05-08 |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101339983B1 (en) | 2011-05-12 | 2013-12-10 | 스미도모쥬기가이고교 가부시키가이샤 | Cryo-pump and fabrication method thereof |
| US9212416B2 (en) | 2009-08-07 | 2015-12-15 | Swagelok Company | Low temperature carburization under soft vacuum |
| US9617632B2 (en) | 2012-01-20 | 2017-04-11 | Swagelok Company | Concurrent flow of activating gas in low temperature carburization |
| RU2709381C1 (en) * | 2018-11-02 | 2019-12-17 | Андрей Павлович Навоев | Method for low-temperature cementation (ltc) of steel |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0421757A (en) * | 1990-05-15 | 1992-01-24 | Nissan Motor Co Ltd | High surface pressure gear |
| JPH09111403A (en) * | 1995-10-11 | 1997-04-28 | Toa Steel Co Ltd | Low strain type carburized and quenched steel stock for gear |
| JPH11117059A (en) * | 1997-08-11 | 1999-04-27 | Komatsu Ltd | Carburized member, its production, and carburizing treatment system |
| JPH11222627A (en) * | 1998-01-30 | 1999-08-17 | Komatsu Ltd | Rolling member and its production |
| JP2002322536A (en) * | 2001-04-23 | 2002-11-08 | Aichi Steel Works Ltd | High strength gear having excellent bending strength of dedendum and pitting resistance, and producing method therefor |
| JP2003027142A (en) * | 2001-07-10 | 2003-01-29 | Aichi Steel Works Ltd | High strength gear having excellent bending strength of dedendum and pitting resistance, and production method therefor |
-
2007
- 2007-08-31 JP JP2007225631A patent/JP5191710B2/en not_active Expired - Fee Related
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0421757A (en) * | 1990-05-15 | 1992-01-24 | Nissan Motor Co Ltd | High surface pressure gear |
| JPH09111403A (en) * | 1995-10-11 | 1997-04-28 | Toa Steel Co Ltd | Low strain type carburized and quenched steel stock for gear |
| JPH11117059A (en) * | 1997-08-11 | 1999-04-27 | Komatsu Ltd | Carburized member, its production, and carburizing treatment system |
| JPH11222627A (en) * | 1998-01-30 | 1999-08-17 | Komatsu Ltd | Rolling member and its production |
| JP2002322536A (en) * | 2001-04-23 | 2002-11-08 | Aichi Steel Works Ltd | High strength gear having excellent bending strength of dedendum and pitting resistance, and producing method therefor |
| JP2003027142A (en) * | 2001-07-10 | 2003-01-29 | Aichi Steel Works Ltd | High strength gear having excellent bending strength of dedendum and pitting resistance, and production method therefor |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9212416B2 (en) | 2009-08-07 | 2015-12-15 | Swagelok Company | Low temperature carburization under soft vacuum |
| US10156006B2 (en) | 2009-08-07 | 2018-12-18 | Swagelok Company | Low temperature carburization under soft vacuum |
| US10934611B2 (en) | 2009-08-07 | 2021-03-02 | Swagelok Company | Low temperature carburization under soft vacuum |
| KR101339983B1 (en) | 2011-05-12 | 2013-12-10 | 스미도모쥬기가이고교 가부시키가이샤 | Cryo-pump and fabrication method thereof |
| US9617632B2 (en) | 2012-01-20 | 2017-04-11 | Swagelok Company | Concurrent flow of activating gas in low temperature carburization |
| US10246766B2 (en) | 2012-01-20 | 2019-04-02 | Swagelok Company | Concurrent flow of activating gas in low temperature carburization |
| US11035032B2 (en) | 2012-01-20 | 2021-06-15 | Swagelok Company | Concurrent flow of activating gas in low temperature carburization |
| RU2709381C1 (en) * | 2018-11-02 | 2019-12-17 | Андрей Павлович Навоев | Method for low-temperature cementation (ltc) of steel |
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| JP5191710B2 (en) | 2013-05-08 |
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