JPH06293939A - Bearing parts excellent in high temperature rolling fatigue characteristic - Google Patents

Bearing parts excellent in high temperature rolling fatigue characteristic

Info

Publication number
JPH06293939A
JPH06293939A JP8093893A JP8093893A JPH06293939A JP H06293939 A JPH06293939 A JP H06293939A JP 8093893 A JP8093893 A JP 8093893A JP 8093893 A JP8093893 A JP 8093893A JP H06293939 A JPH06293939 A JP H06293939A
Authority
JP
Japan
Prior art keywords
less
steel
bearing component
rolling fatigue
high temperature
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
JP8093893A
Other languages
Japanese (ja)
Inventor
Shiyuugorou Adachi
周悟郎 足立
Yoshitake Matsushima
義武 松島
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Kobe Steel Ltd
Original Assignee
Kobe Steel Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Kobe Steel Ltd filed Critical Kobe Steel Ltd
Priority to JP8093893A priority Critical patent/JPH06293939A/en
Publication of JPH06293939A publication Critical patent/JPH06293939A/en
Withdrawn legal-status Critical Current

Links

Abstract

PURPOSE:To provide bearing parts superior in high temp. rolling fatigue characteristic to the ones prepared by using conventional high carbon chromium bearing steel and case hardening steel as a stock. CONSTITUTION:A steel, having a composition which consists of 0.7-1.3% C, <0.5% Si, 0.3-2% Mn, <=0.02% S, 0.51-6% Cr, 0.015-0.06% Al, 0.003-0.02% N, and the balance Fe with inevitable impurities and contains, if necessary, prescribed amounts of Mo, W, V, Nb, Ni, Cu, Co, etc., and in which the contents of P, Ti, and O among the inevitable impurities are controlled to <=0.02%, <=0.003%, and <=0.003%, respectively, is used as a stock. The parts can be obtained by subjecting parts, prepared by using the stock, to quench-and-temper treatment. Further, the average grain size of carbide in the steel is regulated to <=2mum.

Description

【発明の詳細な説明】Detailed Description of the Invention

【0001】[0001]

【産業上の利用分野】本発明は、高炭素クロム軸受部品
や肌焼軸受部品より優れた転動疲労性を有する軸受部品
に関し、殊に高温下の使用環境においても軸受寿命が低
下しない優れた転動疲労性を示す軸受部品に関するもの
である。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing component having a rolling fatigue resistance superior to that of a high carbon chrome bearing component or a case hardening bearing component, and in particular, it has an excellent bearing life even in a use environment at high temperature. The present invention relates to a bearing component that exhibits rolling fatigue.

【0002】[0002]

【従来の技術】自動車や産業機械等に用いられる軸受部
品には、従来から高炭素クロム軸受用鋼が素材として汎
用されており、例えばSUJ1(JISG 4805)
のCr量を増やしたSUJ2が中・小型軸受部品に、ま
たMnやSi量を増やしたSUJ3が大型軸受部品に夫
々多用されてきた。またSCr420(JISG 41
04)に代表される肌焼軸受鋼も、軸受部品の素材とし
て使用されてきた。
2. Description of the Related Art Conventionally, high carbon chromium bearing steel has been widely used as a raw material for bearing parts used in automobiles and industrial machines. For example, SUJ1 (JISG 4805).
The SUJ2 with an increased amount of Cr has been widely used for medium and small-sized bearing parts, and the SUJ3 with an increased amount of Mn and Si has been used for large-sized bearing parts. In addition, SCr420 (JISG 41
Case-hardened bearing steel represented by 04) has also been used as a material for bearing parts.

【0003】しかしながら近年になって、エンジンの高
出力化、高回転化、機械部品の小型化等に伴なって軸受
まわりの温度が上昇していく傾向にあり、こうした状況
のもとでは、SUJ2やSCr420等を素材とした軸
受部品では、高温の使用環境における十分な転動疲労寿
命が得られないという問題があった。
However, in recent years, the temperature around the bearing has tended to rise with the increase in the output of the engine, the increase in the rotation speed, the miniaturization of mechanical parts, etc. Under these circumstances, the SUJ2 A bearing component made of, for example, SCr420 or the like has a problem that a sufficient rolling contact fatigue life cannot be obtained in a high temperature use environment.

【0004】一方過酷な条件下で使用される軸受部品に
は、AISI M50等が素材として使用される様にな
っている。AISI M50を素材とする軸受部品で
は、高温環境下の使用においても優れた転動疲労性が得
られるが、AISI M50は合金元素を多量に含むこ
とから素材費が高くなり、また加工性の点で問題があ
り、加工費も高くなるという欠点がある。
On the other hand, AISI M50 or the like has been used as a material for bearing parts used under severe conditions. A bearing component made of AISI M50 has excellent rolling contact fatigue resistance even when used in a high temperature environment. However, AISI M50 contains a large amount of alloying elements, resulting in high material cost and workability. However, there is a problem that the processing cost becomes high.

【0005】こうしたことから、高温下(300℃以
下)での転動疲労性に優れ、従来のAISI M50と
比較して素材費や加工費が安価な軸受部品の実現が要望
されている。
For these reasons, there is a demand for the realization of a bearing component which is excellent in rolling contact fatigue at high temperatures (300 ° C. or lower) and which is lower in material cost and processing cost than the conventional AISI M50.

【0006】[0006]

【発明が解決しようとする課題】本発明はこうした状況
のもとになされたものであって、その目的は、従来の高
炭素クロム軸受鋼や肌焼鋼を素材としたときよりも優れ
た高温転動疲労性を有し、且つAISI M50と比較
して素材比や加工費が安価である様な軸受部品を提供す
ることにある。
SUMMARY OF THE INVENTION The present invention has been made under these circumstances, and its purpose is to provide a high temperature which is superior to that of a conventional high carbon chromium bearing steel or case hardening steel. An object of the present invention is to provide a bearing component which has rolling fatigue properties and which has a lower material ratio and a lower processing cost than AISI M50.

【0007】[0007]

【課題を解決するための手段】上記目的を達成し得た本
発明とは、C:0.7〜1.3%,Si:0.5%未
満,Mn:0.3〜2%,S:0.02%以下,Cr:
0.51〜6%,Al:0.015〜0.06%,N:
0.003〜0.02%を夫々含有し、残部Feおよび
不可避不純物からなり、該不可避不純物中P:0.02
%以下,Ti:0.003%以下,O:0.003%以
下に夫々抑制してなる鋼を素材とし、該素材によって作
製された部品に、焼入れ・焼戻し処理を施したものであ
り、炭化物の平均粒径が2μm以下である点に要旨を有
するものである。
According to the present invention which has achieved the above object, C: 0.7 to 1.3%, Si: less than 0.5%, Mn: 0.3 to 2%, S : 0.02% or less, Cr:
0.51-6%, Al: 0.015-0.06%, N:
0.003 to 0.02%, respectively, with the balance Fe and unavoidable impurities, and P: 0.02 in the unavoidable impurities.
%, Ti: 0.003% or less, O: 0.003% or less are used as raw materials, and the parts made of the materials are subjected to quenching and tempering treatment, and carbides. It has a gist that the average particle diameter of is less than 2 μm.

【0008】また本発明に係る軸受部品は、上記の元素
を基本成分とするものであるが、必要に応じてMo,
W,V,Nb,Ni,Cu,Co等を含有するものであ
ってもよい。更に、本発明に係る軸受部品において、焼
入れ加熱時に、窒素を表層部に浸入させる処理を施した
ものであり、炭窒化物の平均粒径が2μm以下であるも
のは、高温転動疲労性をさらに向上させることができ
る。
The bearing component according to the present invention contains the above-mentioned elements as basic components.
It may contain W, V, Nb, Ni, Cu, Co or the like. Further, in the bearing component according to the present invention, a treatment for infiltrating nitrogen into the surface layer portion at the time of quenching heating is performed, and a carbon nitride having an average particle size of 2 μm or less has high temperature rolling fatigue resistance. It can be further improved.

【0009】[0009]

【作用】本発明は上述の如く構成されるが、要するに、
高温下での使用で問題となる硬さの低下を抑制するため
に、各種合金元素量を調整して焼戻し軟化抵抗性を向上
させるとともに、炭化物形成元素であるCr(必要によ
って、Mo,W,V,Nb)を添加すことによって積極
的に炭化物を折出させ、且つ焼入れ・焼戻し処理によっ
て炭化物の平均粒径を2μm以下に調整した軸受部品
は、高温での使用条件下でも優れた転動疲労性を示すこ
とを見出し、本発明を完成した。また上記軸受部品にお
いて、焼入れ加熱時に窒素を表層部に浸入させる処理を
施して炭窒化物の平均粒径を2μm以下に調整したもの
は、該軸受部品の高温転動疲労性を更に向上させること
ができることも判明した。まず、本発明に係る軸受部品
における化学成分限定理由は下記の通りである。
The present invention is constructed as described above, but in short,
In order to suppress the decrease in hardness, which is a problem in use at high temperatures, the amount of various alloy elements is adjusted to improve the temper softening resistance, and the carbide forming element Cr (if necessary, Mo, W, V and Nb) are added to cause carbides to positively break out, and the average grain size of carbides is adjusted to 2 μm or less by quenching and tempering treatment. Bearing parts have excellent rolling characteristics even under high temperature use conditions. The inventors have found that they exhibit fatigue properties and completed the present invention. Further, in the above-mentioned bearing component, the one in which nitrogen is infiltrated into the surface layer portion during quenching and heating so that the average grain size of carbonitride is adjusted to 2 μm or less, further improves the high temperature rolling fatigue resistance of the bearing component. It also turned out to be possible. First, the reasons for limiting the chemical components in the bearing component according to the present invention are as follows.

【0010】C:0.7〜1.3% Cはマトリックスに固溶してマルテンサイトを強化し、
また炭化物を増加させて焼戻し後の硬さを向上させるの
に必要な元素である。この様な効果を発揮させる為に
は、Cの含有量は0.7%以上とする必要がある。しか
しながら、C含有量が1.3%を超えると、炭化物が粗
大化し、転動疲労性が低下し、また靭性,切削性,冷間
加工性および温間加工性等が低下する。
C: 0.7-1.3% C is a solid solution in the matrix to strengthen martensite,
It is also an element necessary to increase the amount of carbide and improve the hardness after tempering. In order to exert such an effect, the content of C needs to be 0.7% or more. However, if the C content exceeds 1.3%, the carbides are coarsened, the rolling fatigue is deteriorated, and the toughness, machinability, cold workability, warm workability, etc. are deteriorated.

【0011】Si:0.5%未満 Siは焼戻しの第1段階(マルテンサイト中に固溶して
いるCが炭化物として折出する階段)の終了と第2段階
(残留オーステナイトが分解する段階)の開始を遅ら
せ、焼戻し軟化抵抗生を向上させる元素であるが、0.
5%以上含有させてもその効果は飽和し、切削性,冷間
加工性および温間加工性が著しく低下する。従って、S
iの含有量は0.5%未満とする必要がある。
Si: Less than 0.5% Si is the end of the first stage of tempering (the step in which C dissolved in martensite as carbides is extruded) and the second step (the stage in which residual austenite decomposes). Is an element that delays the onset of heat treatment and improves temper softening resistance resistance.
Even if contained in an amount of 5% or more, the effect is saturated and the machinability, cold workability and warm workability are significantly reduced. Therefore, S
The content of i needs to be less than 0.5%.

【0012】Mn:0.3〜2% Mnは脱酸・脱硫元素であり、また焼入性を向上させる
元素である。Mn含有量が0.3%未満ではこのような
効果は期待できず、また2%を超えて含有してもその効
果は飽和し、かえって切削生,冷温間加工性が低下す
る。
Mn: 0.3-2% Mn is a deoxidizing / desulfurizing element and also an element for improving hardenability. If the Mn content is less than 0.3%, such an effect cannot be expected, and if the Mn content exceeds 2%, the effect is saturated, and rather the cutting raw and cold-warm workability deteriorates.

【0013】S:0.02%以下 Sは鋼中において殆どがMnSの形で含有されており、
切削性を向上させる元素である。しかしながら、O含有
量が少ない場合には却って転動疲労性を低下させ、また
冷間加工性や温間加工性にも悪影響を及ぼす。よって、
これらの点を考慮してS含有量は0.02%以下とす
る。
S: 0.02% or less S is mostly contained in the steel in the form of MnS,
It is an element that improves machinability. However, when the O content is low, the rolling fatigue property is rather deteriorated and the cold workability and the warm workability are adversely affected. Therefore,
Considering these points, the S content is 0.02% or less.

【0014】Cr:0.51〜6% CrはCと結合して微細な炭化物を生成し、高温での硬
さを向上させて高温転動疲労性を向上させる。Cr含有
量が0.51%未満では炭化物が粗大化し、転動疲労性
が低下する。またCr含有量が6%を超えると、切削
性,冷間加工性および温間加工性を低下させる。よっ
て、Cr含有量は0.51〜6%とする。
Cr: 0.51-6% Cr combines with C to form fine carbides, which improves hardness at high temperatures and improves high temperature rolling fatigue. If the Cr content is less than 0.51%, the carbides are coarsened and the rolling fatigue resistance deteriorates. If the Cr content exceeds 6%, the machinability, cold workability and warm workability are deteriorated. Therefore, the Cr content is 0.51 to 6%.

【0015】Al:0.015〜0.06% Alは脱酸と結晶粒の微細化に有効な元素であり、Al
含有量が0.015%未満ではこのような効果はなく、
また0.06%を超えると結晶粒の微細化効果は飽和し
てしまい、さらに多く含有量させると逆に結晶粒が成長
しやすくなる。よって、Alは含有量は0.015〜
0.06%とする。
Al: 0.015 to 0.06% Al is an element effective in deoxidizing and refining crystal grains.
If the content is less than 0.015%, there is no such effect,
If it exceeds 0.06%, the effect of refining the crystal grains is saturated, and if the content is further increased, the crystal grains tend to grow. Therefore, the content of Al is 0.015
It is set to 0.06%.

【0016】N:0.003〜0.02% NはAl,V,Nb等と結合して窒化物を生成し、結晶
粒を微細化して鋼の強靭化を図るのに有効な元素であ
る。N含有量が0.003%未満ではこのような効果は
少なく、また0.02%を超えて含有すると冷間加工性
および温間加工性を低下させる。よってN含有量は、
0.003〜0.02%とする。
N: 0.003 to 0.02% N is an effective element for combining with Al, V, Nb and the like to form a nitride and refining the crystal grains to strengthen the steel. . When the N content is less than 0.003%, such an effect is small, and when the N content exceeds 0.02%, cold workability and warm workability are deteriorated. Therefore, the N content is
It is set to 0.003 to 0.02%.

【0017】本発明の軸受部品は、以上の元素を基本成
分とし残部鉄および不可避不純物からなるものである
が、該不可避不純物中P,Ti,O等は夫々下記の如く
抑制する必要がある。
The bearing component of the present invention comprises the above elements as basic components and the balance iron and unavoidable impurities. P, Ti, O, etc. in the unavoidable impurities must be suppressed as described below.

【0018】P:0.02%以下 Pは靭性を低下させる元素であるから、このP含有量は
極力低減させる必要があり、P含有量は0.02%以下
とする。
P: 0.02% or less Since P is an element that reduces toughness, it is necessary to reduce the P content as much as possible, and the P content is 0.02% or less.

【0019】Ti:0.003%以下 TiはNと結合して粗大なTiNを生成し、転動疲労
性、冷間加工性および温間加工性を低下させる元素であ
り、極力低くする必要がある。こうした観点から、Ti
含有量は、0.003%以下とする。
Ti: 0.003% or less Ti is an element that combines with N to form coarse TiN and deteriorates rolling fatigue resistance, cold workability and warm workability, and it is necessary to reduce it as much as possible. is there. From this viewpoint, Ti
The content is 0.003% or less.

【0020】O:0.003%以下 OはAlやSiと結合し、鋼中において酸化物系介在物
を生成する元素であり、鋼中における含有量が多くなる
と転動疲労性を低下させると共に、切削性、冷間加工性
にも悪影響を及ぼすので極力低減する必要がある。よっ
て、O含有量
O: 0.003% or less O is an element that combines with Al and Si and forms oxide inclusions in the steel. When the content in the steel increases, the rolling fatigue resistance decreases and It also has an adverse effect on machinability and cold workability, so it is necessary to reduce it as much as possible. Therefore, O content

【0021】は0.003%以下とする。Is 0.003% or less.

【0022】本発明の軸受部品には、必要に応じてM
o,W,V,Nb,Ni,Cu,Co等を含有してもよ
い。これらの元素を添加するときの含有量は下記の通り
である。
If necessary, the bearing component of the present invention may have M
You may contain o, W, V, Nb, Ni, Cu, Co etc. The contents when these elements are added are as follows.

【0023】Mo:2%以下およびW:1%以下よりな
る群から選ばれる1種または2種 MoおよびWは、Crと同じく炭化物を生成し、分散強
化によって硬さを大きくするのに有効な元素である。し
かしながらMo含有量が2%およびW含有量が1%を夫
々超えて含有されると効果が飽和すると共に、切削性,
冷間加工性および温間加工性が低下する。
Mo: 1% or 2 selected from the group consisting of 2% or less and W: 1% or less Mo and W are effective in increasing the hardness by dispersion strengthening by forming carbides like Cr. It is an element. However, when the Mo content exceeds 2% and the W content exceeds 1%, the effect is saturated and the machinability,
Cold workability and warm workability are reduced.

【0024】V:0.03〜2%およびNb:0.01
〜0.5%よりなる群から選ばれる1種または2種 VおよびNbは共に鋼中のC,Nと結合して炭窒化物を
生成し、結晶粒を微細化し、且つ焼戻し軟化抵抗性を向
上させるのに有効な元素である。Vの含有量が0.03
%未満およびNb含有量が0.01%未満ではその様な
効果は発揮されず、逆にVの含有量が2%およびNbの
含有量が0.5%をそれぞれ超えて含有されてもその効
果が飽和する。
V: 0.03 to 2% and Nb: 0.01
~ 1% or 2 kinds selected from the group consisting of 0.5% V and Nb both combine with C and N in the steel to form carbonitrides, refine the crystal grains, and temper softening resistance. It is an effective element to improve. V content is 0.03
%, And the Nb content is less than 0.01%, such an effect is not exhibited. Conversely, even if the V content is more than 2% and the Nb content is more than 0.5%, The effect is saturated.

【0025】Ni:3%以下 Niは焼入性を向上させる元素であり、質量の大きな部
品における焼入れ・焼戻し処理を容易にする元素であ
る。また靭性をを向上させる元素でもある。しかしなが
ら、3%を超えて含有されると、切削性,冷間加工性お
よび温間加工性を低下させ、更に焼入れ・焼戻し後に残
留オーステナイトが多量に生成し、寸法安定性が劣化す
る。
Ni: 3% or less Ni is an element that improves the hardenability, and is an element that facilitates the quenching / tempering treatment in a component having a large mass. It is also an element that improves toughness. However, if it is contained in excess of 3%, the machinability, cold workability and warm workability are deteriorated, and a large amount of retained austenite is generated after quenching and tempering, which deteriorates the dimensional stability.

【0026】Cu:1%以下 Cuは焼入性,耐蝕性を増加させる元素であり、且つ耐
摩耗性を向上させる元素であるが、1%を超えると赤熱
脆性を助長して熱間加工時に割れが発生する。よって、
Cuの含有量は1%以下とする必要がある。
Cu: 1% or less Cu is an element that increases hardenability and corrosion resistance, and is an element that improves wear resistance. However, if it exceeds 1%, red hot brittleness is promoted to promote hot working. Cracks occur. Therefore,
The Cu content needs to be 1% or less.

【0027】Co:0.03〜3% Coは耐蝕性を向上させる元素であり、且つ共析点温度
を上げて炭化物および炭窒化物を微細化させる元素であ
る。この様な効果を発揮させるためには、0.03%以
上含有させる必要があるが、3%を超えるとその効果は
飽和する。よって、Coの含有量は,0.03〜3%と
する必要がある。
Co: 0.03 to 3% Co is an element that improves the corrosion resistance and also increases the temperature of the eutectoid point to refine the carbides and carbonitrides. In order to exert such an effect, it is necessary to contain 0.03% or more, but if it exceeds 3%, the effect is saturated. Therefore, the Co content needs to be 0.03 to 3%.

【0028】尚本発明の軸受部品においては、焼入れ加
熱時に、窒素を表層部に浸入させる処理を施したもの
は、高温転動疲労性を更に向上させることができる。以
下本発明を実施例によって更に詳細に説明するが、下記
実施例は本発明を限定する性質のものではなく、前・後
記の趣旨に徴して設計変更することはいずれも本発明の
技術的範囲に含まれるものである。
In the bearing component of the present invention, the high temperature rolling contact fatigue resistance can be further improved if the bearing part is subjected to the treatment of infiltrating nitrogen into the surface layer portion at the time of quenching and heating. Hereinafter, the present invention will be described in more detail with reference to Examples, but the following Examples are not intended to limit the scope of the present invention, and it is technically within the scope of the present invention to change the design in view of the gist of the preceding and the following. Are included in.

【0029】[0029]

【実施例】表1に示す化学成分の本発明鋼No.1 〜9お
よび比較鋼No.10〜18を、小型真空炉にて溶製し
た。尚比較鋼No.17はJISのSUJ2であり、また
比較鋼No.18はJIS SCr420である。
EXAMPLES Steels No. 1 to 9 of the present invention and comparative steels No. 10 to 18 having the chemical composition shown in Table 1 were melted in a small vacuum furnace. The comparative steel No. 17 is JIS SUJ2, and the comparative steel No. 18 is JIS SCr420.

【0030】[0030]

【表1】 [Table 1]

【0031】上記の鋼を熱間鍛造によって、直径60m
mおよび20mmの丸棒に鍛伸した後、比較鋼No.1〜
17については鍛造後ソーキング処理を行い、巨大炭化
物の拡散消失処理を行後、球状化焼鈍を行った。また鋼
No.18については、熱間鍛造後焼鈍を行なった。
The above steel was hot forged to a diameter of 60 m.
m and 20 mm round bar, after forging, comparative steel No. 1
For No. 17, soaking treatment was performed after forging, diffusion disappearance treatment of giant carbide was performed, and then spheroidizing annealing was performed. Steel No. 18 was annealed after hot forging.

【0032】その後、直径60mmの丸棒については、
直径60mm,厚さ5mmの試験片に加工し、下記の熱
処理を行ない、表面をラッピング加工した後、面圧53
0kgf/mm2 の条件で130℃の温度下で転動疲労
試験を実施した。
Then, for a round bar having a diameter of 60 mm,
After processing into a test piece having a diameter of 60 mm and a thickness of 5 mm, the following heat treatment is performed, the surface is lapped, and the surface pressure is 53
A rolling fatigue test was carried out at a temperature of 130 ° C. under the condition of 0 kgf / mm 2 .

【0033】一方直径20mmの丸棒については、直径
20mm,厚さ5mmの試験片に加工し、下記の熱処理
を行なった後、高温硬さ(300℃)の測定、表層部に
おける炭化物の平均粒径を測定した。尚炭化物の平均粒
径の測定は、SEM写真撮影を行ない、その後画像解析
によって平均粒径を求めた。
On the other hand, for a round bar having a diameter of 20 mm, a test piece having a diameter of 20 mm and a thickness of 5 mm was processed and subjected to the heat treatment described below, followed by measurement of high temperature hardness (300 ° C.) and average grain size of carbide in the surface layer portion. The diameter was measured. The average particle size of the carbide was measured by taking an SEM photograph and then determining the average particle size by image analysis.

【0034】<各鋼の熱処理条件> (1) 鋼No.1〜17 焼入れ:840℃×40min/油冷 焼戻し:220℃×2hr/空冷 (2) 鋼No.18 焼入れ:925℃×10hr(浸炭処理)/油冷(カー
ボンポテンシャル:0.8重量%) 焼戻し:250℃×2hr/空冷 これら試験片の高温硬さと高温転動疲労試験結果を表2
に示す。尚転動疲労試験結果についてはL10(10%累
積被損率)寿命で評価した。
<Heat treatment conditions for each steel> (1) Steel No. 1 to 17 Quenching: 840 ° C x 40 min / oil cooling Tempering: 220 ° C x 2 hr / air cooling (2) Steel No. 18 Quenching: 925 ° C x 10 hr ( Carburizing treatment / oil cooling (carbon potential: 0.8% by weight) Tempering: 250 ° C x 2 hr / air cooling Table 2 shows the high temperature hardness and high temperature rolling fatigue test results of these test pieces.
Shown in. The rolling fatigue test results were evaluated by the L 10 (10% cumulative damage rate) life.

【0035】[0035]

【表2】 [Table 2]

【0036】これらの結果より次の様に考察できる。本
発明の実施例(鋼No.1〜9)のものは、いずれも転動
疲労寿命が鋼No.17,18の従来鋼を用いたものより
も優れている。これに対し、C含有量の多い比較鋼No.
10を用いたものは、鋼No.1を用いたものに比べ、粗
大炭化物の生成によって高温硬さが低下し、転動疲労寿
命が低下している。またC含有量の少ない比較鋼No.1
1を用いたものは、鋼No.1を用いたものに比べ、高温
硬さが低下しており、鋼No.16,17の従来鋼を用い
たものよりも転動疲労寿命が短くなっている。Cr含有
量の多い鋼No.12を用いたものは、鋼No.2を用いた
ものに比べ、高温硬さおよび転動疲労寿命とも差がな
く、効果が飽和している。Mo含有量の多い鋼No.13
を用いたものは、鋼No.3を用いたものに比べ、高温硬
さおよび転動疲労寿命とも差がなく、効果が飽和してい
る。V含有量の多い鋼No.14を用いたものは、鋼No.
4を用いたものに比べ、高温硬さおよび転動疲労寿命と
も差がなく、効果が飽和している。更にTi含有量また
はO含有量の多い鋼No.15,16を用いたものは、鋼
No.17,18の従来鋼を用いたものよりも転動疲労寿
命が短くなっている。
From these results, it can be considered as follows. Each of the examples of the present invention (Steel Nos. 1 to 9) has a rolling fatigue life superior to those of the conventional steels of Steel Nos. 17 and 18. On the other hand, comparative steel No.
The steel using No. 10 had a lower high-temperature hardness due to the formation of coarse carbides and the rolling fatigue life was shorter than that using the steel No. 1. Comparative steel No. 1 with low C content
Compared with the one using steel No. 1, the high temperature hardness was lower, and the rolling fatigue life was shorter than that using the conventional steel of steel No. 16 and 17. There is. Compared with the one using steel No. 2, the one using steel No. 12 with a high Cr content has no difference in high temperature hardness and rolling fatigue life, and the effect is saturated. Steel with high Mo content No.13
Compared with the one using steel No. 3, there was no difference in high temperature hardness and rolling fatigue life, and the effect was saturated. Steel No. 14 having a high V content was used.
There is no difference between the high temperature hardness and the rolling fatigue life, and the effect is saturated, as compared with the one using No. Further, the steels using the steel Nos. 15 and 16 having a large content of Ti or O have shorter rolling fatigue life than the steels using steels Nos. 17 and 18 of the conventional steels.

【0037】次に、鋼No.1を用い、球状化処理条件お
よび焼入れ条件を変化させることによって、炭化物の平
均粒径を変化させ、炭化物の平均粒径と高温硬さ(30
0℃)の関係を調査した。その結果を、図1に示す。こ
れにより炭化物の平均粒径を2μm以下に制御すること
は、高温硬さを高めて転動疲労寿命の向上に有効である
ことがわかる。
Next, using steel No. 1, by changing the spheroidizing treatment condition and the quenching condition, the average grain size of the carbide was changed, and the average grain size of the carbide and the high temperature hardness (30
The relationship of 0 ° C.) was investigated. The result is shown in FIG. From this, it is understood that controlling the average grain size of the carbides to 2 μm or less is effective in increasing the high temperature hardness and improving the rolling contact fatigue life.

【0038】更に、本発明鋼No.1,2および比較鋼N
o.15について、以下に示す熱処理を行なった後、高温
硬さの測定と転動疲労試験を行った。その結果を表3に
示す。表3から明らかな様に、窒素を表層部に侵入させ
ることによって、より優れた転動疲労性が得られること
がわかる。 <熱処理条件> 浸炭窒化・焼入れ:870℃×5hr/油冷(カーボン
ポテンシャル:1.0%,アンモニア流量:2リッター
/min) 焼戻し:220℃×2hr/空冷
Further, the invention steel Nos. 1 and 2 and the comparative steel N
For o.15, the following heat treatment was performed, and then high temperature hardness measurement and rolling fatigue test were performed. The results are shown in Table 3. As is apparent from Table 3, it is understood that more excellent rolling contact fatigue resistance can be obtained by injecting nitrogen into the surface layer portion. <Heat treatment conditions> Carbonitriding / quenching: 870 ° C x 5 hr / oil cooling (carbon potential: 1.0%, ammonia flow rate: 2 liter / min) Tempering: 220 ° C x 2 hr / air cooling

【0039】[0039]

【表3】 [Table 3]

【0040】[0040]

【発明の効果】以上述べたように本発明によれば、従来
のM50等の高合金の軸受鋼を使用することなく、高温
下でも優れた転動疲労性を有する軸受部品が実現でき
た。また本発明の軸受部品は、炭化物または炭窒化物が
微細化して硬さが高いので、自動車の歯車粉等の異物が
混入する様な潤滑条件化で使用しても、異物噛み込みに
よる圧痕がつきにくいという利点もある。
As described above, according to the present invention, it is possible to realize a bearing component having excellent rolling fatigue resistance even at high temperature without using a conventional high alloy bearing steel such as M50. In addition, since the bearing component of the present invention has a high hardness due to the refinement of carbides or carbonitrides, even if it is used under a lubricating condition such that foreign matter such as gear powder of an automobile is mixed, indentation due to foreign matter entrapment may occur. It also has the advantage of being difficult to stick to.

【図面の簡単な説明】[Brief description of drawings]

【図1】炭化物の平均粒径と高温硬さの関係を示すグラ
フである。
FIG. 1 is a graph showing the relationship between the average grain size of carbides and high-temperature hardness.

Claims (7)

【特許請求の範囲】[Claims] 【請求項1】 C:0.7〜1.3%(重量%の意味、
以下同じ),Si:0.5%未満,Mn:0.3〜2
%,S:0.02%以下,Cr:0.51〜6%,A
l:0.015〜0.06%,N:0.003〜0.0
2%を夫々含有し、残部Feおよび不可避不純物からな
り、該不可避不純物中P:0.02%以下,Ti:0.
003%以下,O:0.003%以下に夫々抑制してな
る鋼を素材とし、該素材によって作製された部品に、焼
入れ、焼戻し処理を施したものであり、炭化物の平均粒
径が2μm以下であることを特徴とする高温転動疲労性
に優れた軸受部品。
1. C: 0.7 to 1.3% (meaning% by weight,
The same shall apply hereinafter), Si: less than 0.5%, Mn: 0.3 to 2
%, S: 0.02% or less, Cr: 0.51 to 6%, A
1: 0.015-0.06%, N: 0.003-0.0
2% of each, and the balance Fe and unavoidable impurities, P: 0.02% or less in the unavoidable impurities, Ti: 0.
003% or less and O: 0.003% or less are used as raw materials, and the parts made of the materials are subjected to quenching and tempering treatments, and the average grain size of the carbides is 2 μm or less. A bearing component with excellent high temperature rolling fatigue.
【請求項2】 請求項1に記載の軸受部品において、更
にMo:2%以下およびW:1%以下から選ばれる1種
または2種を含有する鋼を素材とするものである軸受部
品。
2. The bearing component according to claim 1, further comprising a steel containing one or two selected from Mo: 2% or less and W: 1% or less.
【請求項3】 請求項1または2に記載の軸受部品おい
て、更にV:0.03〜2%およびNb:0.01〜
0.5%から選ばれる1種または2種を含有する鋼を素
材とするものである軸受部品。
3. The bearing component according to claim 1, further comprising V: 0.03 to 2% and Nb: 0.01 to.
Bearing parts made of steel containing one or two kinds selected from 0.5%.
【請求項4】 請求項1〜3のいずれかに記載の軸受部
品において、更にNi:3%以下を含有する鋼を素材と
するものである軸受部品。
4. The bearing component according to claim 1, which is made of steel containing Ni: 3% or less.
【請求項5】 請求項1〜4のいずれかに記載の軸受部
品において、更にCu:1%以下を含有する鋼を素材と
するものである軸受部品。
5. The bearing component according to claim 1, which further comprises Cu: 1% or less of steel.
【請求項6】 請求項1〜5のいずれかに記載の軸受部
品おいて、更にCo:0.03〜3%を含有する鋼を素
材とするものである軸受部品。
6. The bearing component according to claim 1, which is made of steel containing Co: 0.03 to 3%.
【請求項7】 焼入れ加熱時に窒素を表層部に浸入させ
る処理を施したものであり、炭窒化物の平均粒径が2μ
m以下である請求項1〜6のいずれかに記載の軸受部
品。
7. A carbonitride having an average particle size of 2 μm, which has been subjected to a treatment in which nitrogen is infiltrated into the surface layer during quenching and heating.
The bearing component according to any one of claims 1 to 6, which has a m or less.
JP8093893A 1993-04-07 1993-04-07 Bearing parts excellent in high temperature rolling fatigue characteristic Withdrawn JPH06293939A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP8093893A JPH06293939A (en) 1993-04-07 1993-04-07 Bearing parts excellent in high temperature rolling fatigue characteristic

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP8093893A JPH06293939A (en) 1993-04-07 1993-04-07 Bearing parts excellent in high temperature rolling fatigue characteristic

Publications (1)

Publication Number Publication Date
JPH06293939A true JPH06293939A (en) 1994-10-21

Family

ID=13732417

Family Applications (1)

Application Number Title Priority Date Filing Date
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Country Status (1)

Country Link
JP (1) JPH06293939A (en)

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* Cited by examiner, † Cited by third party
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WO2000028102A1 (en) * 1998-11-11 2000-05-18 Ntn Corporation High-temperature rolling bearing part
DE19982613B3 (en) * 1998-11-11 2013-05-29 Ntn Corp. High-temperature bearings part
DE10062036C2 (en) * 1999-12-14 2003-09-04 Nsk Ltd Rolling bearing and method for producing a component of a rolling bearing
US6602360B2 (en) * 2000-02-10 2003-08-05 Nsk Ltd. Rolling bearing
US7763124B2 (en) 2003-04-16 2010-07-27 Jfe Steel Corporation Steel material with excellent rolling fatigue life and method of producing the same
WO2004092434A1 (en) * 2003-04-16 2004-10-28 Jfe Steel Corporation Steel material with excellent rolling fatigue life and method of producing the same
WO2006068205A1 (en) * 2004-12-24 2006-06-29 Jtekt Corporation Rolling-sliding elements and process for production of the same
JPWO2006068205A1 (en) * 2004-12-24 2008-06-12 株式会社ジェイテクト Rolling and sliding parts and manufacturing method thereof
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JP2007113034A (en) * 2005-10-18 2007-05-10 Kobe Steel Ltd Bearing steel
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WO2010067872A1 (en) * 2008-12-12 2010-06-17 株式会社ジェイテクト Constituent member of bearing, process for production of same, and ball-and-roller bearing provided with the constituent member
JP2010248612A (en) * 2008-12-12 2010-11-04 Jtekt Corp Constituent member of bearing, process for production of same, and ball-and-roller bearing provided with the constituent member
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CN103014536A (en) * 2013-01-06 2013-04-03 奉化市金燕钢球有限公司 High-carbon high-chromium stainless bearing steel and preparation method thereof
CN103667964A (en) * 2013-11-07 2014-03-26 安徽省智汇电气技术有限公司 Medium carbon steel material for pump bearing and preparation method of medium carbon steel material
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