JPH03285042A - Non-heat treated free cutting steel excellent in high temperature ductility - Google Patents
Non-heat treated free cutting steel excellent in high temperature ductilityInfo
- Publication number
- JPH03285042A JPH03285042A JP8667990A JP8667990A JPH03285042A JP H03285042 A JPH03285042 A JP H03285042A JP 8667990 A JP8667990 A JP 8667990A JP 8667990 A JP8667990 A JP 8667990A JP H03285042 A JPH03285042 A JP H03285042A
- Authority
- JP
- Japan
- Prior art keywords
- less
- steel
- cutting steel
- heat treated
- free cutting
- 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.)
- Granted
Links
- 229910000915 Free machining steel Inorganic materials 0.000 title claims abstract description 12
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 4
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 4
- 229910052745 lead Inorganic materials 0.000 claims abstract description 4
- 229910052720 vanadium Inorganic materials 0.000 claims abstract description 4
- 239000012535 impurity Substances 0.000 claims abstract description 3
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 3
- 229910052698 phosphorus Inorganic materials 0.000 claims abstract description 3
- 229910000831 Steel Inorganic materials 0.000 abstract description 20
- 239000010959 steel Substances 0.000 abstract description 20
- 238000009749 continuous casting Methods 0.000 abstract description 7
- 229910052797 bismuth Inorganic materials 0.000 abstract description 2
- 229910052804 chromium Inorganic materials 0.000 abstract description 2
- 229910052748 manganese Inorganic materials 0.000 abstract description 2
- 238000004519 manufacturing process Methods 0.000 abstract description 2
- 238000000034 method Methods 0.000 abstract description 2
- 230000001105 regulatory effect Effects 0.000 abstract 1
- 230000000694 effects Effects 0.000 description 7
- 238000001556 precipitation Methods 0.000 description 6
- 238000005728 strengthening Methods 0.000 description 5
- 230000007423 decrease Effects 0.000 description 4
- 238000005336 cracking Methods 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 229910001566 austenite Inorganic materials 0.000 description 2
- 238000005266 casting Methods 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 150000001247 metal acetylides Chemical class 0.000 description 2
- 239000010953 base metal Substances 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000004745 nonwoven fabric Substances 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 238000005204 segregation Methods 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 238000005496 tempering Methods 0.000 description 1
- 238000009864 tensile test Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Landscapes
- Heat Treatment Of Steel (AREA)
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は、クランク軸等の機械構造用熱間鍛造部品とし
て使用するに適した高温延性の優れた非調質快削鋼に関
するものである。[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a non-thermal free-cutting steel with excellent high-temperature ductility and suitable for use as hot-forged parts for machine structures such as crankshafts. .
（従来の技術）
熱間鍛造部品の製造に関しては、鋳造後、焼入焼戻等の
熱処理によって所定の強度を得ることとしているが、近
年、コストダウンを目的として熱間鍛造のままで所定の
強度を得るいわゆる非調質鋼が採用されるようになって
きた。(Prior art) In the production of hot forged parts, after casting, heat treatments such as quenching and tempering are used to obtain a specified strength. So-called non-temperature steel has come to be used for its strength.
かかる非調質鋼では、高強度化を目的としてＶを、また
被削性の向上を目的としてＳ、Ｐｂを添加するのが一般
的である。In such non-tempered steel, V is generally added for the purpose of increasing strength, and S and Pb are generally added for the purpose of improving machinability.
（発明が解決しようとする課題）
しかしながら、上記したｓ、ｐｂを含む非調質快削鋼は
高温延性が低く、連続鋳造法で製造すると熱間での鋳片
割れが発生し易いという問題があった。そこで、これま
ではかかる非調質快削鋼はインゴットでしか製造できず
、歩留り等コストアップの要因となっていた。(Problems to be Solved by the Invention) However, the above-mentioned non-thermal free-cutting steel containing S and Pb has low high-temperature ductility, and when manufactured by continuous casting, there is a problem in that slab cracking easily occurs during hot casting. Ta. Therefore, until now, such non-tempered free-cutting steel could only be produced in the form of ingots, which caused an increase in yield and other costs.
なお、前記連続鋳造時に発生する高温割れは、Ｓ等の脆
化作用を助長する元素が添加されていることに加えて、
ＡＩＮがオーステナイト粒界に析出すること、及びオー
ステナイト粒内にＶ等の強い析出強化元素が析出するこ
とにより、粒内に対する粒界の相対的延性が低下し、連
続鋳造鋳片の矯正臼げの際に鋳片の表面又は表面直下に
微小亀裂が生成し、圧延時にその亀裂が開口することが
原因である。In addition, the hot cracking that occurs during continuous casting is caused by the addition of elements that promote embrittlement such as S,
Due to the precipitation of AIN at the austenite grain boundaries and the precipitation of strong precipitation-strengthening elements such as V within the austenite grains, the relative ductility of the grain boundaries with respect to the inside of the grains decreases, and the straightening of continuously cast slabs decreases. The cause is that microcracks are generated on or just below the surface of the slab, and the cracks open during rolling.
本発明はかかる問題点に鑑みて成されたものであり、ｓ
、ｐｂを含有した非調質快削鋼において、高温延性を改
善し連続鋳造法によっても製造可能な非調質快削鋼を提
供することを目的としている。The present invention has been made in view of such problems, and s
The present invention aims to provide a non-thermal free-cutting steel containing Pb, which has improved high-temperature ductility and can be manufactured by continuous casting.
（課題を解決するための手段）
上記した本発明の目的を達成するために、本発意者らは
、鋭意実験・研究を重ねた結果、高温延性を改善し連続
鋳造法によっても製造可能な非調質快削鋼を得るために
は、以下の条件を満足することが有効であることを知見
した。(Means for Solving the Problems) In order to achieve the above-mentioned object of the present invention, the inventors of the present invention have conducted intensive experiments and research to find a non-woven fabric with improved high-temperature ductility that can also be manufactured by continuous casting. It has been found that it is effective to satisfy the following conditions in order to obtain tempered free-cutting steel.
■ 高温延性を向上するには、ＡＩＮの析出を抑制する
ことが有効であり、これには鋼中ＯＮの含有量を下げる
ことが対策となるが、非調質鋼ではＮは■と結合して化
合物を生成し、析出強化に寄与するため、鋼中のＮの含
有量は下げることができない。■ To improve high-temperature ductility, it is effective to suppress the precipitation of AIN, and a countermeasure for this is to lower the ON content in the steel, but in non-thermal steel, N combines with ■. The content of N in steel cannot be lowered because it generates compounds and contributes to precipitation strengthening.
従って、ＡＩの添加量をほぼ脱酸剤として寄与する量だ
けとすれば有効であること。Therefore, it is effective if the amount of AI added is approximately the amount that contributes as a deoxidizing agent.
■ 析出強化元素であるＶの添加量を高温延性が低下し
ない範囲に限定することが有効であること。(2) It is effective to limit the amount of V, which is a precipitation-strengthening element, to a range that does not reduce high-temperature ductility.
本発明は、かかる知見に基づいて成されたものであり、
その要旨は、重量％で、Ｃ： ０．６０％以下、Ｓｉ
： １．５％以下、Ｍｎ ： ２．０％以下、Ｐ ：
０．０３５％以下、Ｓ ： ０．０４０〜０．５０％、
Ｐｂ ： ０．３０％以下、Ｃｒ ： ０．５０％以下
、Ｖ：０．１５％以下、Ｎ：０．００７０〜０．０１５
０％、Ａｌ ： ０．００５％以下を含有し、必要に応
じて更に、Ｃａ ： ０．０１％以下、Ｂｉ ： ０．
３０％以下の１種以上を含有し、残部は実質的にＰｅ及
び不可避的不純物から成る高温延性の優れた非調質快削
鋼である。The present invention was made based on such knowledge,
The gist is that in weight %, C: 0.60% or less, Si
: 1.5% or less, Mn: 2.0% or less, P:
0.035% or less, S: 0.040-0.50%,
Pb: 0.30% or less, Cr: 0.50% or less, V: 0.15% or less, N: 0.0070 to 0.015
0%, Al: 0.005% or less, and further contains Ca: 0.01% or less, Bi: 0.0% or less, if necessary.
It is a non-thermal free-cutting steel with excellent high-temperature ductility, containing 30% or less of one or more elements, with the remainder essentially consisting of Pe and unavoidable impurities.
（作 用）
以下に本発明における鋼の成分組成の限定理由について
説明する。(Function) The reason for limiting the composition of steel in the present invention will be explained below.
Ｃ：Ｃは固溶強化及び■、Ｃｒなどと炭化物を形成して
鋼の強度を増すのに必須の元素であるが、０．６０％を
超えると必要以上に硬化し加工性が低下することから本
発明ではその含有量を０゜６０％以下とした。C: C is an essential element for solid solution strengthening and forming carbides with Cr, etc. to increase the strength of steel, but if it exceeds 0.60%, it will harden more than necessary and reduce workability. Therefore, in the present invention, the content is set to 0°60% or less.
Ｓｉ ： Ｓｉは鋼の脱酸剤として有効な成分であるが
、その含有量が１．５％を超えると介在物が増加し、延
性が低下するため、本発明ではその含有量を１．５％以
下と定めた。Si: Si is an effective component as a deoxidizing agent for steel, but if its content exceeds 1.5%, inclusions increase and ductility decreases, so in the present invention, the content is reduced to 1.5%. % or less.
Ｍｎ ： Ｍｎは母材の強度及び靭性を向上させる作用
があるが、その含有量が２．０％を趙えると、靭性劣化
及び偏析が増加するため、本発明ではその含有量を２．
０％以下と定めた。Mn: Mn has the effect of improving the strength and toughness of the base metal, but if its content exceeds 2.0%, toughness deterioration and segregation will increase, so in the present invention, the content is reduced to 2.0%.
It was set as 0% or less.
Ｐ：Ｐの含有量を低減させることは鋼の強靭化に極めて
有効であり、好ましくはＰは極力少ない方が良いが、完
全になくすることはできない。P: Reducing the content of P is extremely effective in making steel tougher, and it is preferable to reduce P as much as possible, but it cannot be completely eliminated.
しかし、本発明鋼の性能を安定して発揮させるためには
、Ｐは０．０３５％以下とする必要がある。However, in order to stably exhibit the performance of the steel of the present invention, P needs to be 0.035% or less.
Ｓ：Ｓは被削性の改善に不可欠な元素であるが、０．０
４０％未満では顕著な効果が認められず、他方０．５０
％を超えると熱間加工性を劣化させるため、本発明では
その含有量を０．０４０％〜０．５０％と定めた。S: S is an essential element for improving machinability, but 0.0
At less than 40%, no significant effect was observed; on the other hand, at 0.50
In the present invention, the content is set at 0.040% to 0.50%, since hot workability deteriorates when the content exceeds 0.040% to 0.50%.
ｐｂ ： ｐｂは被削性を向上するのに有効な元素であ
るが、多く添加すると機械的性質が著しく低下するから
本発明ではその上限を０．３０％とした。PB: PB is an effective element for improving machinability, but if added in large quantities, the mechanical properties deteriorate significantly, so in the present invention, the upper limit is set to 0.30%.
Ｃｒ ： Ｃｒは炭化物の形成により硬度を向上するの
に有効な元素であるが、コスト上から本発明では上限を
０．５０％とした。Cr: Cr is an effective element for improving hardness by forming carbides, but in view of cost, the upper limit is set to 0.50% in the present invention.
■：■は高強度化に有効な元素であるが、その含有量が
０．１５％を超えると熱間加工性を劣化させるため、本
発明ではその含有量を０．１５％以下と定めた。■:■ is an effective element for increasing strength, but if its content exceeds 0.15%, hot workability deteriorates, so in the present invention, its content is set at 0.15% or less. .
Ｎ：Ｎは■と化合物を形成し、析出強化に寄与するため
非調質鋼には必須の元素である。しかし、含有量が０．
００７０％未満では添加の効果は少なく、他方０．０１
５０％を超えると青熱脆性の問題が発生する。このため
、本発明では添加量を０．００７０％〜０．０１５０％
と定めた。N: N forms a compound with ■ and contributes to precipitation strengthening, so it is an essential element for non-tempered steel. However, the content is 0.
If it is less than 0.070%, the effect of addition is small; on the other hand, if it is 0.01
If it exceeds 50%, the problem of blue brittleness occurs. Therefore, in the present invention, the amount added is 0.0070% to 0.0150%.
It was determined that
ＡＩ：Ａｌは脱酸剤として寄与するが、ＡＩＮの析出を
抑制するため、本発明ではその含有量を０．００５％以
下と定めた。AI: Al contributes as a deoxidizing agent, but in order to suppress precipitation of AIN, the content is set at 0.005% or less in the present invention.
Ｃａ ： Ｃａは鋼中の酸化物を被削性に適したものに
変化させる性質があり、その結果、被削性改善に有効な
元素であるが、添加量が多くなると介在物が増加し、逆
に被削性が低下することから本発明ではその上限を０．
０１％とした。Ca: Ca has the property of changing oxides in steel to ones suitable for machinability, and as a result, it is an effective element for improving machinability, but when the amount added increases, inclusions increase, On the contrary, machinability decreases, so in the present invention, the upper limit is set to 0.
It was set as 01%.
Ｂｉ ： Ｂｉはｐｂに類僚した効果があり、主に５Ｓ
ｐｂと複合添加して使用されるが、コスト及び添加効果
の向上の点から本発明ではその上限を０．３０％とした
。Bi: Bi has similar effects to pb, mainly on 5S.
Although it is used in combination with pb, the upper limit is set to 0.30% in the present invention in order to improve cost and addition effects.
（実 施 例）
次に本発明を実施例により比較例と対比しながら説明す
る。なお、これらの実施例は本発明の効果を示す例示で
あって、本発明の技術的範囲を何等制限するものでない
ことは勿論である。(Example) Next, the present invention will be explained using Examples while comparing with Comparative Examples. It should be noted that these Examples are merely illustrative of the effects of the present invention, and of course do not limit the technical scope of the present invention.
先ず通常の方法によって下記表に示す成分組成の鋼（符
号Ａ−Ｈ及びＡ”〜Ｈ’ ）を溶製した。First, steels having the compositions shown in the table below (coded as A-H and A''-H') were melted by a conventional method.
鋼Ａ−Ｈは本発明の範囲内の組成を有しているもので、
鋼Ａ′〜Ｈ”は表中＊印を付した点において本発明の範
囲から外れたものである。Steels A-H have compositions within the scope of the present invention,
Steels A' to H'' are outside the scope of the present invention in the points marked * in the table.
これらの溶製鋼を連続鋳造法によって１５０ ｋｇ鋼塊
となし、この表面部より試験片を採取し、高温引張試験
を行った。These molten steels were made into a 150 kg steel ingot by a continuous casting method, and a test piece was taken from the surface of the ingot and subjected to a high-temperature tensile test.
上記表より、本発明鋼は高温延性に優れていることが明
らかである。From the above table, it is clear that the steel of the present invention has excellent high-temperature ductility.
（発明の効果）
以上説明したように、本発明によると、従来鋼に比べて
７００〜１０００°Ｃの延性が大幅に増加し、しかも連
続鋳造法によって製造した場合にも鋳片割れが発生せず
、従来鋼と比較して大幅なコストダウンが図れる。(Effects of the Invention) As explained above, according to the present invention, the ductility at 700 to 1000°C is significantly increased compared to conventional steel, and even when manufactured by continuous casting, slab cracking does not occur. , it is possible to achieve significant cost reductions compared to conventional steel.
Claims (2)
以下、Ｍｎ：２．０％以下、Ｐ：０．０３５％以下、Ｓ
：０．０４０〜０．５０％、Ｐｂ：０．３０％以下、Ｃ
ｒ：０．５０％以下、Ｖ：０．１５％以下、Ｎ：０．０
０７０〜０．０１５０％、Ａｌ：０．００５％以下を含
有し、残部は実質的にＦｅ及び不可避的不純物から成る
ことを特徴とする高温延性の優れた非調質快削鋼。(1) In weight%, C: 0.60% or less, Si: 1.5%
Below, Mn: 2.0% or less, P: 0.035% or less, S
: 0.040 to 0.50%, Pb: 0.30% or less, C
r: 0.50% or less, V: 0.15% or less, N: 0.0
A non-thermal free-cutting steel with excellent high-temperature ductility, characterized in that it contains 0.070 to 0.0150%, Al: 0.005% or less, and the remainder essentially consists of Fe and inevitable impurities.
Ｂｉ：０．３０％以下の１種以上を含有することを特徴
とする請求項１記載の高温延性の優れた非調質快削鋼。(2) As a component element, further Ca: 0.01% or less,
The non-thermal free-cutting steel with excellent high-temperature ductility according to claim 1, characterized in that it contains one or more types of Bi: 0.30% or less.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8667990A JP2926856B2 (en) | 1990-03-30 | 1990-03-30 | Non-tempered free-cutting steel with excellent hot ductility |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8667990A JP2926856B2 (en) | 1990-03-30 | 1990-03-30 | Non-tempered free-cutting steel with excellent hot ductility |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH03285042A true JPH03285042A (en) | 1991-12-16 |
| JP2926856B2 JP2926856B2 (en) | 1999-07-28 |
Family
ID=13893708
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP8667990A Expired - Lifetime JP2926856B2 (en) | 1990-03-30 | 1990-03-30 | Non-tempered free-cutting steel with excellent hot ductility |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2926856B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000282169A (en) * | 1999-04-02 | 2000-10-10 | Nippon Steel Corp | Steel excellent in forgeability and machinability |
| US7195736B1 (en) | 2000-02-10 | 2007-03-27 | Sanyo Special Steel Co., Ltd. | Lead-free steel for machine structural use with excellent machinability and low strength anisotropy |
| CN110029263A (en) * | 2019-04-22 | 2019-07-19 | 南京钢铁股份有限公司 | The process of sulfur-bearing Aluminum steel production |
-
1990
- 1990-03-30 JP JP8667990A patent/JP2926856B2/en not_active Expired - Lifetime
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000282169A (en) * | 1999-04-02 | 2000-10-10 | Nippon Steel Corp | Steel excellent in forgeability and machinability |
| US7195736B1 (en) | 2000-02-10 | 2007-03-27 | Sanyo Special Steel Co., Ltd. | Lead-free steel for machine structural use with excellent machinability and low strength anisotropy |
| US7445680B2 (en) | 2000-02-10 | 2008-11-04 | Sanyo Special Steel Co., Ltd. | Lead-free steel for machine structural use with excellent machinability and low strength anisotropy |
| CN110029263A (en) * | 2019-04-22 | 2019-07-19 | 南京钢铁股份有限公司 | The process of sulfur-bearing Aluminum steel production |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2926856B2 (en) | 1999-07-28 |
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