JPH04314842A - Steel material for shaft parts excellent in induction hardenability - Google Patents
Steel material for shaft parts excellent in induction hardenabilityInfo
- Publication number
- JPH04314842A JPH04314842A JP7974691A JP7974691A JPH04314842A JP H04314842 A JPH04314842 A JP H04314842A JP 7974691 A JP7974691 A JP 7974691A JP 7974691 A JP7974691 A JP 7974691A JP H04314842 A JPH04314842 A JP H04314842A
- Authority
- JP
- Japan
- Prior art keywords
- weight
- steel
- less
- hardenability
- shaft parts
- 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- Withdrawn
Links
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 33
- 239000010959 steel Substances 0.000 title claims abstract description 33
- 230000006698 induction Effects 0.000 title claims abstract description 15
- 239000000463 material Substances 0.000 title description 13
- 239000012535 impurity Substances 0.000 claims abstract description 3
- 239000000203 mixture Substances 0.000 abstract description 4
- 229910052698 phosphorus Inorganic materials 0.000 abstract description 3
- 238000010008 shearing Methods 0.000 abstract description 2
- 229910052717 sulfur Inorganic materials 0.000 abstract description 2
- 229910052799 carbon Inorganic materials 0.000 abstract 1
- 229910052757 nitrogen Inorganic materials 0.000 abstract 1
- 229910052760 oxygen Inorganic materials 0.000 abstract 1
- 230000001105 regulatory effect Effects 0.000 abstract 1
- 238000005520 cutting process Methods 0.000 description 14
- 238000010791 quenching Methods 0.000 description 10
- 230000000694 effects Effects 0.000 description 9
- 238000005096 rolling process Methods 0.000 description 7
- 230000000171 quenching effect Effects 0.000 description 6
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 5
- 238000010438 heat treatment Methods 0.000 description 5
- 238000005482 strain hardening Methods 0.000 description 5
- 230000015572 biosynthetic process Effects 0.000 description 4
- 238000000034 method Methods 0.000 description 3
- 238000010301 surface-oxidation reaction Methods 0.000 description 3
- 238000005275 alloying Methods 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- 238000005242 forging Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 238000005496 tempering Methods 0.000 description 2
- 238000005097 cold rolling Methods 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 230000008094 contradictory effect Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000005098 hot rolling Methods 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000005204 segregation Methods 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
Landscapes
- Shafts, Cranks, Connecting Bars, And Related Bearings (AREA)
Abstract
Description
【0001】0001
【産業上の利用分野】本発明は、熱間圧延のままで冷間
加工性及び高周波焼入性に優れた軸部品用鋼材に関し、
特に自動車用ドライブシャフト、等速ジョイントに好適
な鋼に関する。[Industrial Application Field] The present invention relates to a steel material for shaft parts that has excellent cold workability and induction hardenability even after hot rolling.
In particular, it relates to steel suitable for automobile drive shafts and constant velocity joints.
【0002】0002
【従来の技術】自動車用ドライブシャフト等の軸部品は
、温間鍛造後、高周波焼入、焼戻し処理を行い、表面硬
さを高くして使用される。しかし、近年は、部品が多品
種化する傾向にあり、寸法精度向上の要求が生じ、温間
鍛造前に、圧延のままの鋼材を事前にシャーで細分化し
、温間鍛造後さらに冷間加工する方法が取られている。2. Description of the Related Art Shaft parts such as drive shafts for automobiles are used after warm forging, followed by induction hardening and tempering to increase surface hardness. However, in recent years, there has been a tendency for parts to become more diverse, and there has been a demand for improved dimensional accuracy. A method is being taken to do so.
【0003】また、近年、環境問題、特にCO2 ガス
低減を目的とし、自動車部品に対する軽量化の要求があ
り、軸部品などの場合、軽量化の点から、最も重要な製
品特性であるねじり強度の向上が、要望されている。一
般に、ねじり強度を上昇させるためには高周波焼入れに
よる焼入硬化深さを増加させる手法がとられている。焼
入硬化深さを増加させるためには、高周波焼入条件の変
更、特に高周波誘導加熱装置の周波数の低減、あるいは
鋼材の合金元素量を増加させることが考えられる。高周
波誘導加熱装置の周波数を下げるためには、新しく高価
な高周波発振機の購入が必要であり、経済的ではない。
一方、合金元素を増加した場合には、素材の強度が上昇
し、切削、冷間加工などに問題が生じる。さらに、焼入
れ深さ(X/r、X:焼入層の深さ、r:軸材の半径)
の増加のみで高強度を達成するのは効率的でなく、X/
rが0.5を越えて焼入れ深さを増加しても強度の増加
は著しくない。[0003] In recent years, there has been a demand for lighter automobile parts in order to reduce environmental issues, especially CO2 gas.In the case of shaft parts, etc., torsional strength, which is the most important product characteristic, has been required in order to reduce weight. Improvement is required. Generally, in order to increase torsional strength, a method of increasing the quench hardening depth by induction hardening is used. In order to increase the quench hardening depth, it is possible to change the induction hardening conditions, particularly to reduce the frequency of the high frequency induction heating device, or to increase the amount of alloying elements in the steel material. In order to lower the frequency of the high-frequency induction heating device, it is necessary to purchase a new and expensive high-frequency oscillator, which is not economical. On the other hand, when the alloying element is increased, the strength of the material increases, causing problems in cutting, cold working, etc. Furthermore, the quenching depth (X/r, X: depth of the quenching layer, r: radius of the shaft material)
It is not efficient to achieve high strength only by increasing
Even if r exceeds 0.5 and the quenching depth is increased, the strength does not increase significantly.
【0004】0004
【発明が解決しようとする課題】前記要求特性を満足す
るには、従来法のように、焼入れ性向上元素を単に添加
又は増加させただけでは、問題は、解決されない。つま
りシャー切断性、冷間加工性と焼入性は、相反するもの
であり、これら特性を両立させる技術は未だ確立されて
いない。Problems to be Solved by the Invention In order to satisfy the above-mentioned required characteristics, the problem cannot be solved by simply adding or increasing the hardenability improving element as in the conventional method. In other words, shear cuttability, cold workability, and hardenability are contradictory, and a technology that achieves both of these properties has not yet been established.
【0005】本発明が前記問題点を解決するために、良
好なシャー切断性を有し、冷間加工時の工具寿命が長く
、高ねじり強度を有する軸部材、すなわち、高周波焼入
性と冷間加工性の優れた高強度軸部品用鋼材を提供する
ことを目的とする。In order to solve the above-mentioned problems, the present invention provides a shaft member that has good shear cutting properties, a long tool life during cold working, and high torsional strength. The purpose is to provide a high-strength steel material for shaft parts with excellent machinability.
【0006】[0006]
【課題を解決するための手段】本発明はC :0.3
5〜0.60重量%、
Si:0.05重量%以下、
Mn:0.50重量%超〜0.65重量%未満P :
0.020重量%以下、
S :0.035重量%以下、
Cr:0.30重量%超〜0.50重量%未満Ti:0
.01〜0.05重量%、
B :0.0003〜0.0050重量%、N :
0.005重量%以下
O :0.002重量%以下
を含有し、残部Fe及び不可避的不純物より成る高周波
焼入性に優れた軸部品用鋼である。さらに上記成分に加
えて、
Mo:0.05〜0.50重量%
を含有すると一層好適な高周波焼入性に優れた軸部品鋼
を得る。[Means for solving the problems] The present invention provides C: 0.3
5 to 0.60 wt%, Si: 0.05 wt% or less, Mn: more than 0.50 wt% to less than 0.65 wt% P:
0.020% by weight or less, S: 0.035% by weight or less, Cr: more than 0.30% by weight and less than 0.50% by weight, Ti: 0
.. 01-0.05% by weight, B: 0.0003-0.0050% by weight, N:
This is a steel for shaft parts that contains 0.005% by weight or less of O: 0.002% by weight or less, and the remainder is Fe and unavoidable impurities, and has excellent induction hardenability. Furthermore, when Mo: 0.05 to 0.50% by weight is contained in addition to the above-mentioned components, a shaft component steel having even more suitable induction hardenability can be obtained.
【0007】[0007]
【作用】本発明者らは、鋭意検討した結果より、シャー
切断性に関与する圧延のままの鋼材TS(引張強さ)に
及ぼす化学組成の影響は、
C>Mn>Cr>Mo>Si>B
の順であり、焼入性に関しては、
B>C>Mn>Mo<Cr>Si
の順であることを知見した。これらの知見をもとに、熱
処理工程で、表面酸化寄因となるSiは、圧延材TS、
焼入性へ与える影響が少ないので、極力低減させ、B,
Cr,Moについては、TSへの影響が小さく、焼入性
を向上させることができ、積極的に活用することにより
、目的を達成でき、本発明を構成した。[Function] As a result of extensive studies, the inventors have found that the influence of chemical composition on as-rolled steel TS (tensile strength), which is involved in shear cutting properties, is as follows: C>Mn>Cr>Mo>Si> It was found that the order of hardenability was B>C>Mn>Mo<Cr>Si. Based on these findings, Si, which causes surface oxidation in the heat treatment process, can be removed from rolled material TS,
Since it has little effect on hardenability, it should be reduced as much as possible, and B.
Regarding Cr and Mo, they have a small influence on TS and can improve hardenability, and by actively utilizing them, the purpose can be achieved and the present invention has been constructed.
【0008】本発明の成分限定理由について述べる。
C:高周波焼入性への影響がもっとも強い元素であり、
所要ねじり強度を確保するためには、焼入硬化深さを高
めねばならず、0.35重量%以上必要とし、良好なシ
ャー切断性、転造性を得るため、上限を0.60重量%
とした。
Si:鋼材の焼入性に効果が少く、転造時の工具寿命を
低減させる作用があり、できるだけ低減することが望ま
しいが熱処理の表面酸化も考慮し、0.05重量%以下
とした。[0008] The reason for limiting the ingredients of the present invention will be described. C: It is an element that has the strongest influence on induction hardenability,
In order to secure the required torsional strength, it is necessary to increase the quench hardening depth, which requires 0.35% by weight or more, and to obtain good shear cutting properties and rolling properties, the upper limit is set to 0.60% by weight.
And so. Si: It has little effect on the hardenability of steel materials and has the effect of reducing tool life during rolling, so it is desirable to reduce it as much as possible, but considering surface oxidation during heat treatment, it is set to 0.05% by weight or less.
【0009】Mn:鋼材の焼入性を向上させる元素であ
り、同時に鋼中のSを固定して熱間脆性を防止する元素
である。0.50重量%以下では、焼入性向上効果がな
い。0.65重量%以上では転造時の工具寿命を低下さ
せるので0.65重量%未満とした。
P:焼入時の焼割れを助長する元素であるので、極力低
減することが望ましく、0.02重量%まで許容される
。Mn: An element that improves the hardenability of steel, and at the same time fixes S in the steel to prevent hot embrittlement. If it is less than 0.50% by weight, there is no effect of improving hardenability. If it is 0.65% by weight or more, the life of the tool during rolling will be reduced, so the content is set to be less than 0.65% by weight. P: Since it is an element that promotes quench cracking during quenching, it is desirable to reduce it as much as possible, and it is allowed up to 0.02% by weight.
【0010】S:被削性を向上させる元素であるが、冷
間加工性に関しては、低下させるため、上限を0.03
5重量%とした。
Cr:焼入性向上に有効な元素であるとともに、冷間加
工時の変形能を向上させるため、0.30重量%超添加
する。シャー切断性、コスト面より、0.50重量%未
満とする。[0010] S: An element that improves machinability, but it lowers cold workability, so the upper limit is set to 0.03.
The content was 5% by weight. Cr: is an element effective in improving hardenability, and is added in excess of 0.30% by weight in order to improve deformability during cold working. From the viewpoint of shear cutting performance and cost, the content should be less than 0.50% by weight.
【0011】Mo:Crと同様に焼入性を向上させ、耐
軟化抵抗性に有効な元素であり、0.05重量%以上必
要とする。0.50重量%を超えれば、冷間加工性、軸
中心付近の靭性劣化を招く。
Ti:Nと結合してTiNを形成し、Bの焼入性向上効
果を発揮させる元素で、積極的に添加するが、0.01
重量%未満では、その効果が小さく、一方0.05重量
%を超えて含有すると、TiNが多量に形成され疲労特
性の劣化を招き、0.01〜0.05重量%の範囲に限
定する。Mo: Like Cr, it is an element that improves hardenability and is effective in softening resistance, and is required in an amount of 0.05% by weight or more. If it exceeds 0.50% by weight, cold workability and toughness near the shaft center will deteriorate. Ti: An element that combines with N to form TiN and exhibits the effect of improving the hardenability of B. Although it is actively added, the amount of 0.01
If the content is less than 0.05% by weight, the effect will be small, while if the content exceeds 0.05% by weight, a large amount of TiN will be formed, leading to deterioration of fatigue properties, so the content is limited to a range of 0.01 to 0.05% by weight.
【0012】B:微量の添加により焼入性を向上させる
元素であり、0.0003重量%未満では、その効果が
小さく、また0.0050重量%を越えて添加すると、
Bの焼入性効果が低下する。
N:Bの焼入性向上のため極力低減させるが、0.00
5重量%を越えて含有されると、粗大なTiNの形成及
びフリー固溶N量の増加をまねき、疲労特性、軸中心付
の靭性劣化を招く。[0012] B: An element that improves hardenability when added in a trace amount; if it is less than 0.0003% by weight, the effect is small, and if it is added in excess of 0.0050% by weight,
The hardenability effect of B is reduced. N: It is reduced as much as possible to improve the hardenability of B, but 0.00
If the content exceeds 5% by weight, this leads to the formation of coarse TiN and an increase in the amount of free solid solution N, leading to deterioration of fatigue properties and toughness of the shaft center.
【0013】O:酸化物を形成し、冷間加工性を阻害す
るので、上限を0.002重量%とした。O: Forms oxides and impedes cold workability, so the upper limit was set at 0.002% by weight.
【0014】[0014]
【実施例】本発明鋼を、比較鋼、従来鋼とともに実施例
に示す。表1、表3に示す化学組成の5t鋼塊を溶製し
、ビレット圧延、棒鋼圧延を経て、直径25mmの直棒
とした。この棒鋼を素材として、シャー切断後、温間鍛
造、冷間加工、転造によるセレーション加工し、高周波
焼入焼戻しを実施した。[Example] The steel of the present invention is shown in Examples together with comparative steel and conventional steel. A 5t steel ingot having the chemical composition shown in Tables 1 and 3 was melted and subjected to billet rolling and steel bar rolling to form a straight bar with a diameter of 25 mm. This steel bar was used as a raw material, and after shear cutting, it was subjected to serration processing by warm forging, cold working, and rolling, and then induction quenching and tempering.
【0015】シャー切断性、鋼材の焼入深さ、ねじり強
度及び転造時の工具寿命を調査した結果を表2、表4に
示す。なお、工具寿命は、従来鋼(No.31)を1と
して評価した。
No.1〜12:本発明鋼においては、シャー切断性、
工具寿命比、ねじり強度において従来鋼と比較し、優れ
た特性を示している。[0015] Tables 2 and 4 show the results of an investigation of shear cutting performance, quenching depth of steel, torsional strength, and tool life during rolling. Note that the tool life was evaluated with the conventional steel (No. 31) as 1. No. 1 to 12: In the steel of the present invention, shear cutting property,
It shows superior properties compared to conventional steel in terms of tool life ratio and torsional strength.
【0016】No.13,14:C量が0.35重量%
を下回るとねじり強度が従来鋼より低下し、C量が0.
60重量%より高い場合は、圧延まま時のTS増加によ
りシャー破損が多発する。
No.15:Si量が0.05重量%より高いと、熱処
理時表面酸化が促進され、シャー破損を招く。[0016]No. 13,14: C content is 0.35% by weight
If the C content is less than 0.0, the torsional strength will be lower than that of conventional steel, and the C content will be less than 0.
If it is higher than 60% by weight, shear damage will occur frequently due to an increase in TS during as-rolling. No. 15: When the amount of Si is higher than 0.05% by weight, surface oxidation is promoted during heat treatment, leading to shear damage.
【0017】No.16,17:Mnについて、0.5
0重量%以下では、シャー切断性は良好であるが、ねじ
り強度が従来鋼より向上しない。多量のMnは、圧延ま
ま材のTS増加を招き、加工性に影響を及ぼす。
No.18,19:P,Sがそれぞれ0.020重量%
、0.035重量%を越えて多く含まれる場合又は残存
する場合、粒界P偏析、MnS介在物の形成により、シ
ャー切断時、鋼材側に割れが発生する。[0017]No. 16,17: For Mn, 0.5
When the content is 0% by weight or less, the shear cutting properties are good, but the torsional strength is not improved compared to conventional steel. A large amount of Mn causes an increase in TS of the as-rolled material and affects workability. No. 18,19: P and S are each 0.020% by weight
, or if it remains in excess of 0.035% by weight, cracks will occur on the steel material side during shear cutting due to grain boundary P segregation and the formation of MnS inclusions.
【0018】No.20,21,22:Cr、Moの添
加は、ねじり強度は、増加するが、圧延のままのTSの
増加をもたらし、加工性は低下する。
No.23:Tiの増加は、TiNの形成を多くし、特
に、シャー切断時、鋼材側の割れ発生を引き起こす。[0018]No. 20, 21, 22: Addition of Cr and Mo increases torsional strength, but increases as-rolled TS and reduces workability. No. 23: An increase in Ti increases the formation of TiN, which causes cracks to occur on the steel side, especially during shear cutting.
【0019】No.24:多量のBは、粒界に偏析し、
シャー切断時鋼材側の割れ発生を招く。
No.25:多量のNは粗大TiNを形成させ、鋼材の
靭性、延性を低下させ、加工性、シャー切断性を阻害す
る。[0019]No. 24: A large amount of B segregates at grain boundaries,
This causes cracks to occur on the steel side when shearing. No. 25: A large amount of N forms coarse TiN, reduces the toughness and ductility of the steel material, and impedes workability and shear cutting performance.
【0020】No.26:多量の酸化物形成により、シ
ャー切断時鋼材での割れを誘発する。[0020]No. 26: The formation of a large amount of oxides induces cracks in the steel material during shear cutting.
【0021】[0021]
【表1】[Table 1]
【0022】[0022]
【表2】[Table 2]
【0023】[0023]
【表3】[Table 3]
【0024】[0024]
【表4】[Table 4]
【0025】[0025]
【発明の効果】本発明は、シャー切断、冷間加工、ねじ
り強度を満足する軸部品用鋼材の最適成分系を見出し、
生産性、コストを阻害することなく、製造する技術の確
立を図った。また、一般機械部品にも適用できる。[Effects of the Invention] The present invention has discovered an optimal composition system for a steel material for shaft parts that satisfies shear cutting, cold working, and torsional strength.
The aim was to establish a manufacturing technology that would not hinder productivity or cost. It can also be applied to general mechanical parts.
Claims (2)
Si:0.05重量%以下、 Mn:0.50重量%超〜0.65重量%未満P :
0.020重量%以下、 S :0.035重量%以下、 Cr:0.30重量%超〜0.50重量%未満Ti:0
.01〜0.05重量%、 B :0.0003〜0.0050重量%、N :
0.005重量%以下 O :0.002重量%以下 を含有し、残部Fe及び不可避的不純物より成る高周波
焼入性に優れた軸部品用鋼。[Claim 1] C: 0.35 to 0.60% by weight,
Si: 0.05% by weight or less, Mn: more than 0.50% by weight and less than 0.65% by weight P:
0.020% by weight or less, S: 0.035% by weight or less, Cr: more than 0.30% by weight and less than 0.50% by weight, Ti: 0
.. 01-0.05% by weight, B: 0.0003-0.0050% by weight, N:
A steel for shaft parts containing 0.005% by weight or less of O: 0.002% by weight or less, with the balance consisting of Fe and unavoidable impurities, which has excellent induction hardenability.
鋼。2. The shaft component steel with excellent induction hardenability according to claim 1, further containing Mo: 0.05 to 0.50% by weight.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP7974691A JPH04314842A (en) | 1991-04-12 | 1991-04-12 | Steel material for shaft parts excellent in induction hardenability |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP7974691A JPH04314842A (en) | 1991-04-12 | 1991-04-12 | Steel material for shaft parts excellent in induction hardenability |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH04314842A true JPH04314842A (en) | 1992-11-06 |
Family
ID=13698795
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP7974691A Withdrawn JPH04314842A (en) | 1991-04-12 | 1991-04-12 | Steel material for shaft parts excellent in induction hardenability |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH04314842A (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2004027258A (en) * | 2002-06-21 | 2004-01-29 | Sanyo Special Steel Co Ltd | Cutting-finished bar steel having excellent shear cuttability and method of producing the bar steel |
JP2005320575A (en) * | 2004-05-07 | 2005-11-17 | Sumitomo Metal Ind Ltd | Seamless steel pipe and its production method |
-
1991
- 1991-04-12 JP JP7974691A patent/JPH04314842A/en not_active Withdrawn
Cited By (5)
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JP2004027258A (en) * | 2002-06-21 | 2004-01-29 | Sanyo Special Steel Co Ltd | Cutting-finished bar steel having excellent shear cuttability and method of producing the bar steel |
JP2005320575A (en) * | 2004-05-07 | 2005-11-17 | Sumitomo Metal Ind Ltd | Seamless steel pipe and its production method |
WO2005116284A1 (en) * | 2004-05-07 | 2005-12-08 | Sumitomo Metal Industries, Ltd. | Seamless steel pipe and method for production thereof |
US7316143B2 (en) | 2004-05-07 | 2008-01-08 | Sumitomo Metal Industries, Ltd. | Seamless steel tubes and method for producing the same |
JP4706183B2 (en) * | 2004-05-07 | 2011-06-22 | 住友金属工業株式会社 | Seamless steel pipe and manufacturing method thereof |
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