JP2936754B2 - Ti alloy excellent in cold forgeability - Google Patents
Ti alloy excellent in cold forgeabilityInfo
- Publication number
- JP2936754B2 JP2936754B2 JP3908991A JP3908991A JP2936754B2 JP 2936754 B2 JP2936754 B2 JP 2936754B2 JP 3908991 A JP3908991 A JP 3908991A JP 3908991 A JP3908991 A JP 3908991A JP 2936754 B2 JP2936754 B2 JP 2936754B2
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- Japan
- Prior art keywords
- alloy
- deformation resistance
- weight
- cold
- type
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Description
【０００１】[0001]
【産業上の利用分野】本発明は、冷間鍛造性に優れたＴ
ｉ合金に関し、詳細には従来のβ型Ｔｉ合金と同程度の
強度を維持しつつ、冷間加工性及び延性を向上させたＴ
ｉ合金に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a T
Regarding the i-alloy, specifically, a T alloy having improved cold workability and ductility while maintaining the same strength as a conventional β-type Ti alloy.
It relates to the i alloy.
【０００２】[0002]
【従来の技術】Ｔｉ合金は添加元素の種類や量によって
組織がかわり、α型，α＋β型，β型等に分類され、各
々個有の特性を示すことが知られている。これまでのＴ
ｉ合金としてはα＋β型Ｔｉ合金であるＴｉ−６Ａｌ−
４Ｖが最も多く利用されており、航空機や宇宙開発機器
を中心として需要が拡大しつつある。最近では上記Ｔｉ
合金の、軽く，強く、しかも耐食性に優れるという特性
に着目して、自動車や家庭用電化製品等をはじめとする
量産型民生品の部品として使用することも検討されはじ
めている。量産に適した部品としては冷間鍛造が効率良
く行なえることが要求され、この為には変形抵抗が小さ
く延性が大きいことが必要である。しかしながら前記α
＋β型Ｔｉ合金であるＴｉ−６Ａｌ−４Ｖは冷間加工性
に乏しく量産用の素材としては不適当である。2. Description of the Related Art It is known that Ti alloys are classified into α-type, α + β-type, β-type, etc., depending on the type and amount of added elements, and each has its own characteristic. The previous T
As the i alloy, Ti-6Al- which is an α + β type Ti alloy
4V is used most frequently, and demand is expanding mainly in aircraft and space development equipment. Recently, the above Ti
Paying attention to the characteristics of the alloy that is light, strong, and excellent in corrosion resistance, the use of the alloy as a part for mass-produced consumer products such as automobiles and household electric appliances has begun to be studied. As a part suitable for mass production, it is required that cold forging can be performed efficiently, and for this purpose, it is necessary that deformation resistance is small and ductility is large. However, the α
Ti-6Al-4V, which is a + β-type Ti alloy, has poor cold workability and is unsuitable as a material for mass production.
【０００３】冷間加工に適したＴｉ合金としてはβ型Ｔ
ｉ合金が有力視されており、応力誘起マルテンサイト変
態を生じるＴｉ−１６Ｖ−４Ｓｎや変形が双晶で起こる
Ｔｉ−１６Ｖ−１０Ｓｎ等が既に開発されている。本発
明者らが上記２種類のβ型Ｔｉ合金について変形抵抗を
比較調査したところ、Ｔｉ−１６Ｖ−４Ｓｎでは0.2 ％
耐力が３０kgf/mm2程度、引張強さが５０kgf/mm2程度で
あるのに対して、Ｔｉ−１６Ｖ−１０Ｓｎの0.2 ％耐力
と引張強さは共に６０kgf/mm2程度にも及び、Ｔｉ−１
６Ｖ−４Ｓｎの方が変形抵抗の面で優れていることを確
認している。[0003] As a Ti alloy suitable for cold working, β-type T
The i alloy is considered to be promising, and Ti-16V-4Sn, which causes stress-induced martensitic transformation, and Ti-16V-10Sn, which deforms twin, have been developed. The present inventors have conducted a comparative study on the deformation resistance of the above two types of β-type Ti alloys.
While the yield strength is about 30 kgf / mm 2 and the tensile strength is about 50 kgf / mm 2 , both the 0.2% proof stress and tensile strength of Ti-16V-10Sn are about 60 kgf / mm 2 , 1
It has been confirmed that 6V-4Sn is superior in terms of deformation resistance.
【０００４】但し、該Ｔｉ−１６Ｖ−４Ｓｎは据込み限
界においては既存のβ型Ｔｉ合金であるＴｉ−１５Ｖ−
３Ｃｒ−３Ｓｎ−３Ａｌ等に劣り、またＡｌを含有して
いないため耐酸化性に不安が残ると共に、時効処理時に
析出するα相が軟らかくて高強度が得られず、かと言っ
てＡｌを添加すると冷間鍛造性が極端に低下するという
問題を有している。However, Ti-16V-4Sn is an existing β-type Ti alloy, Ti-15V-Sn, at the upsetting limit.
Inferior to 3Cr-3Sn-3Al, etc., and because it does not contain Al, there remains anxiety in oxidation resistance, and the α phase precipitated during aging treatment is soft and high strength cannot be obtained. There is a problem that the cold forgeability is extremely reduced.
【０００５】ところで本発明者らは冷間鍛造性に優れた
Ｔｉ合金を開発すべく研究を重ねてきており、これまで
にも冷間鍛造に適した強度と延性を有するＴｉ合金を発
明して先に出願を行なった（特開平１−１２９９４
１）。The present inventors have been studying to develop a Ti alloy having excellent cold forgeability, and have invented a Ti alloy having strength and ductility suitable for cold forging. Filed earlier (Japanese Patent Application Laid-Open No. 1-12994)
1).
【０００６】しかしながら上記先願合金で据込み鍛造を
行ない、既存のβ型Ｔｉ合金であるＴｉ−１５Ｖ−３Ｃ
ｒ−３Ｓｎ−３Ａｌと冷間鍛造性を比較したところ、変
形抵抗の面では優れているが、据込み限界の点ではＴｉ
−１５Ｖ−３Ｃｒ−３Ｓｎ−３Ａｌが８０％の圧縮率を
有するのに対して、上記先願合金は７５％と幾分低い圧
縮率を示している。そこでさらに冷間鍛造性の優れたＴ
ｉ合金を開発することが要望されている。However, upsetting forging is performed using the above-mentioned prior-art alloy, and the existing β-type Ti alloy Ti-15V-3C
Comparing r-3Sn-3Al with cold forgeability, it is excellent in terms of deformation resistance, but Ti in terms of upsetting limit.
While the -15V-3Cr-3Sn-3Al has a compression ratio of 80%, the prior application alloy has a somewhat lower compression ratio of 75%. Therefore, T which is more excellent in cold forgeability
There is a need to develop i-alloys.
【０００７】[0007]
【発明が解決しようとする課題】本発明は上記事情に着
目してなされたものであって、既存のβ型Ｔｉ合金であ
るＴｉ−１５Ｖ−３Ｃｒ−３Ｓｎ−３Ａｌと同程度の据
込み限界を有すると共に変形抵抗がＴｉ−１６Ｖ−４Ｓ
ｎと同程度若しくはそれ以上に低い冷間鍛造性に優れた
Ｔｉ合金を提供することを目的とするものである。SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has an upsetting limit equivalent to that of an existing β-type Ti alloy, Ti-15V-3Cr-3Sn-3Al. With deformation resistance of Ti-16V-4S
An object of the present invention is to provide a Ti alloy excellent in cold forgeability that is as low as or higher than n.
【０００８】[0008]
【課題を解決するための手段】上記目的を達成した本発
明とはＭｏおよび／またはＮｂ：0.5 〜１８重量％，
Ｖ：１３〜１９重量％，Ａｌ：0.5 〜６重量％，Ｓｎ：
0.5 〜６重量％を含有し、残部がＴｉおよび不可避不純
物からなることを要旨とするものである。According to the present invention which has achieved the above objects, the present invention relates to Mo and / or Nb: 0.5 to 18% by weight,
V: 13 to 19% by weight, Al: 0.5 to 6% by weight, Sn:
The gist of the invention is that it contains 0.5 to 6% by weight, with the balance being Ti and unavoidable impurities.
【０００９】[0009]
【作用】本発明者らは変形に伴なって応力誘起マルテン
サイト変態を示すβ型Ｔｉ合金であるＴｉ−１６Ｖ−４
Ｓｎが低い変形抵抗を示すことに着目して、これに種々
の合金元素を添加して実験を繰り返す中で、Ａｌを適量
添加して適当な強度をもたせた上で、ある種のβ相安定
化元素を添加すれば、Ａｌ添加によるα相の安定化を抑
制し、強度及び冷間加工性が共に適切なレベルに改良さ
れることを知見して本発明に想到した。The present inventors have determined that Ti-16V-4, a .beta.-type Ti alloy exhibiting stress-induced martensitic transformation with deformation.
Paying attention to the fact that Sn exhibits low deformation resistance, while adding various alloying elements to this and repeating the experiment, adding an appropriate amount of Al to give appropriate strength, and then stabilizing a certain β phase The present inventors have found that the addition of Al element suppresses the stabilization of the α phase due to the addition of Al, and improves both the strength and the cold workability to appropriate levels.
【００１０】上記β相安定化元素を選択するにあたって
は、Ｍｏ，Ｎｂ，Ｆｅ，Ｃｒの中から選び、種々の添加
量を変えて実験を行なったところ、次の様な結果を得
た。即ちＦｅ，Ｃｒは合金の据込み限界を向上させる点
では寄与するが、変形抵抗をも上昇させてしまうのに対
し、Ｍｏ，Ｎｂは据込み限界を向上させると同時に変形
抵抗もＴｉ−１６Ｖ−４Ｓｎより低く抑えることが可能
であることを見い出したのである。In selecting the above-mentioned β-phase stabilizing element, experiments were carried out by selecting from among Mo, Nb, Fe, and Cr and varying the amount of addition, and the following results were obtained. In other words, Fe and Cr contribute to improving the upsetting limit of the alloy, but also increase the deformation resistance, whereas Mo and Nb improve the upsetting limit and simultaneously increase the deformation resistance of Ti-16V-. They have found that it is possible to keep it below 4Sn.
【００１１】以下本発明合金における各成分元素の添加
量の限定理由について述べる。The reasons for limiting the amount of each component element added in the alloy of the present invention will be described below.
【００１２】Ａｌは時効処理によって十分な引張強度を
得る目的で添加するが、0.5 重量％未満では時効処理を
施しても十分な引張強度が得られず、６重量％を超える
と延性及び冷間鍛造性が著しく低下するので、Ａｌの添
加量は0.5 〜６重量％とした。Al is added for the purpose of obtaining sufficient tensile strength by aging treatment. However, if it is less than 0.5% by weight, sufficient tensile strength cannot be obtained even after aging treatment, and if it exceeds 6% by weight, ductility and cold Since the forgeability is significantly reduced, the amount of Al added is set to 0.5 to 6% by weight.
【００１３】ＭｏとＮｂは据込み限界を向上させ、変形
抵抗を低くする目的で添加するが、0.5 重量％未満では
その効果が見られず、１８重量％を超えると変形抵抗が
かえって上昇するので、0.5 〜１８重量％とした。尚こ
の変形抵抗の上昇は固溶硬化によるものであると考えら
れる。また本合金においてＭｏとＮｂはほぼ同様に作用
するので、両元素の添加量の合計が上記範囲内に入って
いれば、単独に用いても同時に用いても良い。Mo and Nb are added for the purpose of improving the upsetting limit and lowering the deformation resistance. However, if the content is less than 0.5% by weight, the effect is not seen, and if it exceeds 18% by weight, the deformation resistance increases rather. , 0.5 to 18% by weight. It is considered that this increase in deformation resistance is due to solid solution hardening. Since Mo and Nb act almost in the same manner in the present alloy, they may be used alone or simultaneously as long as the total amount of the two elements is within the above range.
【００１４】ＶおよびＳｎの範囲を決定するにあたって
はＡｌおよびＭｏとＮｂを前記範囲内で添加した上で、
ＶおよびＳｎの添加量を変動させながら冷間鍛造性を評
価することによって行なった。Ｖは１３重量％未満では
据込み限界が低く、１９重量％を超えて添加すると変形
抵抗が上昇するので１３〜１９重量％とした。一方Ｓｎ
は0.5 重量％未満になると据え込み限界が極端に低下
し、６重量％を超えて添加すると変形抵抗が上昇するの
で0.5 〜６重量％とした。尚上記据込み限界の低下は焼
入れ時に拡散変態が進行するからであると考えられ、ま
た変形抵抗の上昇は固溶硬化によるものと思われる。In determining the ranges of V and Sn, Al, Mo and Nb are added within the above ranges,
The evaluation was performed by evaluating the cold forgeability while changing the amounts of V and Sn added. If V is less than 13% by weight, the upsetting limit is low, and if it exceeds 19% by weight, the deformation resistance increases, so V is set to 13 to 19% by weight. On the other hand, Sn
When the content is less than 0.5% by weight, the upsetting limit is extremely lowered. When the content exceeds 6% by weight, the deformation resistance is increased. The lowering of the upsetting limit is considered to be due to the diffusion transformation during quenching, and the increase in deformation resistance is considered to be due to solid solution hardening.
【００１５】[0015]
【実施例】表１及び表２に示す種々の組成を有するＴｉ
合金をボタン溶解にて溶製し（各６００ｇ）、２０mmφ
になるまで１０００℃で約５０％の熱間鍛造を行なった
後、９００℃で１０分間保持することによって溶体化処
理を施し水冷を行なった。これより直径１６mm，高さ２
４mmの円柱状試験片を切り出し、端面拘束状態で冷間に
おける据込み鍛造を行なった。EXAMPLES Ti having various compositions shown in Tables 1 and 2 was used.
The alloy is melted by button melting (600 g each), 20 mmφ
After about 50% hot forging was performed at 1000 ° C. until the solution became, a solution treatment was performed by holding at 900 ° C. for 10 minutes, and water cooling was performed. 16mm in diameter and 2 height
A 4 mm cylindrical test piece was cut out and subjected to cold upsetting forging with the end face constrained.
【００１６】冷間鍛造性の評価は参考文献［塑性と加
工，第２７巻，第３０４号（１９８６），５６８頁「冷
間鍛造用炭素鋼線材の変形抵抗と延性に関するデータシ
ート」］記載の手法に基づいて７０％及び８０％の変形
抵抗を測定すると共に、８０％圧縮したときの割れ発生
の有無を観察して行なった。The evaluation of cold forgeability is described in the reference document [Plasticity and Working, Vol. 27, No. 304 (1986), p. 568, “Data Sheet on Deformation Resistance and Ductility of Carbon Steel Wire for Cold Forging”]. The deformation resistance of 70% and 80% was measured based on the technique, and the presence or absence of cracking when compressed by 80% was observed.
【００１７】また一部の合金に対しては５００℃で８時
間保持する時効処理を施して引張試験を行ない、引張強
度及び伸びを測定した。結果は表１及び表２に併記す
る。Some of the alloys were subjected to an aging treatment at 500 ° C. for 8 hours and subjected to a tensile test to measure tensile strength and elongation. The results are shown in Tables 1 and 2.
【００１８】[0018]
【表１】 [Table 1]
【００１９】[0019]
【表２】 [Table 2]
【００２０】Ｎo.１〜２０は各合金成分が本発明範囲に
ある実施例であり、８０％の圧縮によっても割れの発生
は見られず、７０％及び８０％の変形抵抗も比較的低い
値を示している。Ｎo.１〜１４の実施例については時効
処理後の引張性質を調べたが、引張強度は９０kgf/mm2
台と適度であり、伸びも１４％以上と高い。Nos. 1 to 20 are examples in which each alloy component is within the range of the present invention. No cracking is observed even at 80% compression, and the deformation resistance at 70% and 80% is relatively low. Is shown. For the examples of Nos. 1 to 14, the tensile properties after the aging treatment were examined, and the tensile strength was 90 kgf / mm 2.
The table is moderate, and the elongation is as high as 14% or more.
【００２１】Ｎo.２１〜３６は合金成分のいずれかが本
発明範囲をはずれた場合の比較例であり、下記の様に冷
間加工性若しくは時効処理後の引張強度の点で劣ること
がわかる。尚表１では８０％の圧縮で割れが発生した場
合は変形抵抗が測定できないので空欄にしている。Ｎo.
２１，２２はＭｏ，Ｎｂの添加量が少ない場合の比較例
であり、８０％の圧縮で割れが発生しており、変形抵抗
は測定不可能になっている。Nos. 21 to 36 are comparative examples in which one of the alloy components is out of the range of the present invention, and it is found that the alloy is inferior in cold workability or tensile strength after aging treatment as described below. . In Table 1, when a crack occurs at a compression of 80%, the deformation resistance cannot be measured. No.
Reference numerals 21 and 22 are comparative examples in which the amounts of Mo and Nb added are small. Cracks are generated by 80% compression, and the deformation resistance cannot be measured.
【００２２】Ｎo.２３〜２５はＭｏ，Ｎｂの添加量が多
過ぎる場合の比較例であり、変形抵抗が高い。Ｎo.２
６，２７はＡｌの含有量が少ない場合の比較例であり、
時効処理後の引張強さが低い。Ｎo.２８，２９はＡｌの
含有量が多い場合の比較例であり、８０％の圧縮によっ
て割れが発生すると共に時効処理後の伸びが７％以下と
著しく低い。Ｎo.３０はＳｎ量が少ない場合の比較例で
あり、８０％の圧縮によって割れが発生している。一方
Ｎo.３１はＳｎ量が多い場合の比較例であり、７０％及
び８０％での変形抵抗が著しく高い。Ｎo.３２はＶの添
加量が少ない場合の比較例であり、８０％の圧縮によっ
て割れが発生している。これに対してＮo.３３はＶの添
加量が多い場合の比較例であり、７０％及び８０％の変
形抵抗が高い。Ｎo.３４〜３６はＭｏ若しくはＮｂに代
わってＦｅ若しくはＣｒが添加された場合の比較例であ
り、いずれも変形抵抗が著しく高い。Nos. 23 to 25 are comparative examples in which the added amounts of Mo and Nb are too large, and have high deformation resistance. No.2
6 and 27 are comparative examples when the content of Al is small,
Low tensile strength after aging treatment. Nos. 28 and 29 are comparative examples in which the content of Al is large. Cracks are generated by 80% compression, and the elongation after aging treatment is remarkably low at 7% or less. No. 30 is a comparative example in which the amount of Sn is small, and cracks are generated by 80% compression. On the other hand, No. 31 is a comparative example in which the amount of Sn is large, and the deformation resistance at 70% and 80% is remarkably high. No. 32 is a comparative example when the added amount of V is small, and cracks are generated by 80% compression. On the other hand, No. 33 is a comparative example in which the added amount of V is large, and the deformation resistance of 70% and 80% is high. Nos. 34 to 36 are comparative examples in which Fe or Cr is added instead of Mo or Nb, and all have significantly high deformation resistance.
【００２３】[0023]
【発明の効果】本発明は以上の様に構成されているの
で、既存のβ型Ｔｉ合金よりも変形抵抗が低く、しかも
８０％までの据込み鍛造が可能なＴｉ合金を提供するこ
とが可能となった。As described above, according to the present invention, it is possible to provide a Ti alloy having lower deformation resistance than existing β-type Ti alloys and capable of upsetting forging up to 80%. It became.
Claims (1)
量％，Ｖ：１３〜１９重量％，Ａｌ：0.5 〜６重量％，
Ｓｎ：0.5 〜６重量％を含有し、残部がＴｉおよび不可
避不純物からなることを特徴とする冷間鍛造性に優れた
Ｔｉ合金。1. Mo and / or Nb: 0.5 to 18% by weight, V: 13 to 19% by weight, Al: 0.5 to 6% by weight,
Sn: a Ti alloy containing 0.5 to 6% by weight, with the balance being Ti and inevitable impurities, and having excellent cold forgeability.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2-31060 | 1990-02-09 | ||
| JP3106090 | 1990-02-09 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04214830A JPH04214830A (en) | 1992-08-05 |
| JP2936754B2 true JP2936754B2 (en) | 1999-08-23 |
Family
ID=12320934
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3908991A Expired - Fee Related JP2936754B2 (en) | 1990-02-09 | 1991-02-08 | Ti alloy excellent in cold forgeability |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2936754B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20130209824A1 (en) * | 2012-02-15 | 2013-08-15 | Rti International Metals, Inc. | Titanium alloys |
-
1991
- 1991-02-08 JP JP3908991A patent/JP2936754B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH04214830A (en) | 1992-08-05 |
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