JPH02138429A - High strength beta-series titanium alloy having excellent corrosion resistance and stress corrosion cracking resistance - Google Patents
High strength beta-series titanium alloy having excellent corrosion resistance and stress corrosion cracking resistanceInfo
- Publication number
- JPH02138429A JPH02138429A JP10890889A JP10890889A JPH02138429A JP H02138429 A JPH02138429 A JP H02138429A JP 10890889 A JP10890889 A JP 10890889A JP 10890889 A JP10890889 A JP 10890889A JP H02138429 A JPH02138429 A JP H02138429A
- Authority
- JP
- Japan
- Prior art keywords
- resistance
- alloy
- titanium alloy
- content
- corrosion resistance
- 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
- 230000007797 corrosion Effects 0.000 title claims abstract description 29
- 238000005260 corrosion Methods 0.000 title claims abstract description 29
- 229910001069 Ti alloy Inorganic materials 0.000 title claims abstract description 24
- 238000005336 cracking Methods 0.000 title claims abstract description 10
- 239000000956 alloy Substances 0.000 claims abstract description 26
- 229910045601 alloy Inorganic materials 0.000 claims abstract description 24
- 229910052758 niobium Inorganic materials 0.000 claims abstract description 9
- 229910052715 tantalum Inorganic materials 0.000 claims abstract description 9
- 229910052726 zirconium Inorganic materials 0.000 claims abstract description 9
- 239000010936 titanium Substances 0.000 claims abstract description 8
- 229910052720 vanadium Inorganic materials 0.000 claims abstract description 8
- 239000012535 impurity Substances 0.000 claims abstract description 7
- 229910052750 molybdenum Inorganic materials 0.000 claims abstract description 7
- 229910052742 iron Inorganic materials 0.000 claims abstract description 4
- 230000032683 aging Effects 0.000 abstract description 13
- 230000035882 stress Effects 0.000 abstract description 4
- 229910052719 titanium Inorganic materials 0.000 abstract description 3
- 230000001105 regulatory effect Effects 0.000 abstract 3
- 229910052782 aluminium Inorganic materials 0.000 abstract 2
- 230000000052 comparative effect Effects 0.000 description 12
- 239000003129 oil well Substances 0.000 description 11
- 230000000694 effects Effects 0.000 description 6
- 239000000203 mixture Substances 0.000 description 5
- 238000011156 evaluation Methods 0.000 description 4
- 238000013001 point bending Methods 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 3
- 238000005098 hot rolling Methods 0.000 description 3
- 238000001556 precipitation Methods 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- 238000009864 tensile test Methods 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- RWSOTUBLDIXVET-UHFFFAOYSA-N Dihydrogen sulfide Chemical compound S RWSOTUBLDIXVET-UHFFFAOYSA-N 0.000 description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 2
- 229910052804 chromium Inorganic materials 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 230000018109 developmental process Effects 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 229910000037 hydrogen sulfide Inorganic materials 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- 239000006104 solid solution Substances 0.000 description 2
- 230000000087 stabilizing effect Effects 0.000 description 2
- 229910052717 sulfur Inorganic materials 0.000 description 2
- 229910052721 tungsten Inorganic materials 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- -1 Moreover Inorganic materials 0.000 description 1
- 101000993059 Homo sapiens Hereditary hemochromatosis protein Proteins 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 238000007545 Vickers hardness test Methods 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 229910000856 hastalloy Inorganic materials 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 229910000765 intermetallic Inorganic materials 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 239000003208 petroleum Substances 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000005728 strengthening Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Abstract
Description
【発明の詳細な説明】
［産業上の利用分野］
この発明は、油井環境および地熱環境において使用され
るパイプ、アクセサリ−および生産数何機器用材料等に
用いられる、耐食性および耐応力腐食割れ性に優れた高
強度β系チダン合金に関するものである。[Detailed Description of the Invention] [Industrial Application Field] This invention provides corrosion resistance and stress corrosion cracking resistance for use in pipes, accessories, and materials for equipment used in oil well environments and geothermal environments. The present invention relates to a high-strength β-based titanium alloy with excellent properties.
［従来の技術］
近年、石油資源の開発環境は、高深度油井の開発に代表
されるように、高濃度のＣＬイオン、高い硫化水素ガス
および炭酸ガス分圧を有する高温且つ高圧環境となりつ
つある。また、単体の硫黄（以下、Ｓｏという）が存在
する腐食環境もあるといわれている。従来、このような
厳しい環境において使用することを目的とした合金とし
て、下記のものが提案されている。[Prior Art] In recent years, the development environment for petroleum resources has become a high-temperature and high-pressure environment with high concentrations of CL ions, high hydrogen sulfide gas, and high partial pressures of carbon dioxide gas, as typified by the development of deep oil wells. . It is also said that there are corrosive environments in which elemental sulfur (hereinafter referred to as So) exists. Conventionally, the following have been proposed as alloys intended for use in such harsh environments.
（１）チタンは、一般に優れた耐食性を有し、且つ、熱
処理によって、高強度を得ることができる等、油井管に
必要な特性を備えている。このため、Ｔｉ−１５Ｖ−３
Ａ（１−３Ｃｒ−３Ｓｎなどの高強度チタン合金が、前
述のような油井環境および地熱環境で試験的に使用され
ている。(1) Titanium generally has excellent corrosion resistance and has properties necessary for oil country tubular goods, such as being able to obtain high strength through heat treatment. Therefore, Ti-15V-3
High strength titanium alloys such as A(1-3Cr-3Sn) have been used experimentally in oil well and geothermal environments as described above.
（２）実験室的には、Ｔｉ−３ＡｆＴｉ−３Ａｆｉ−８
Ｖ−６Ｃｒ−４からなるβ−Ｃチタン合金（商品名）の
Ｃリング試験がオートクレーブ中で行なわれ、Ｓｏのな
い条件下で、良好な結果を示すことが、１９８６年、米
国において１発行された、’ Ｉｎｄｕｓｔｒｉａｌ
Ａｐｐｌｉｃａｔｉｏｎ ｏｆ Ｔｉｔａｎｉｕｍ ａ
ｎｄＺｉｒｕｃｏｎｉｕｍ’第１４４〜１６１頁に開示
されている。(2) In the laboratory, Ti-3AfTi-3Afi-8
A C-ring test was conducted on β-C titanium alloy (trade name) consisting of V-6Cr-4 in an autoclave, and it was published in the United States in 1986 that it showed good results under So-free conditions. 'Industrial
Application of Titanium a
nd Ziruconium', pages 144-161.
（３）ＮｉをベースとするハステロイＣ−２７６（商品
名）が実用に供されている。(3) Hastelloy C-276 (trade name) based on Ni is in practical use.
（４）特開昭６３−３１７６３７号公報には、ＴｉをＭ
Ｏに３ｗｔ、％以上添加した合金が開示されている。(4) Japanese Patent Application Laid-open No. 63-317637 discloses that Ti is M
An alloy in which 3 wt.% or more of O is added is disclosed.
［発明が解決しようとする課題］
しかしながら、上記（１）の合金は、耐食性および応力
腐食割れ性（以下、耐ＳＣＣ性という）ともに不充分で
、厳しい油井環境および地熱環境での使用に耐えられな
かった。[Problems to be Solved by the Invention] However, the above alloy (1) has insufficient corrosion resistance and stress corrosion cracking resistance (hereinafter referred to as SCC resistance), and cannot withstand use in harsh oil well environments and geothermal environments. There wasn't.
（２）上記（２）の合金は、Ｓｏを含まない油井環境に
おいて使用可能であることが開示されているのみで、Ｓ
６を含む厳しい環境下での使用に耐えられるか否かは不
明である。(2) The alloy mentioned in (2) above is only disclosed to be usable in an oil well environment that does not contain So.
It is unknown whether it can withstand use under harsh environments including 6.
（３）上記（３）の合金は、密度が高いので、 ６００
０ｍ以上の高深度油井ではその重量が問題となる。(3) The alloy in (3) above has a high density, so 600
In deep oil wells of 0 m or more, the weight becomes a problem.
また、８０ ｋｇｆ／ ｖｔｓ２の強度を得るのに５０
％以上の冷間加工を施こす必要があるので、高強度を得
にくい。Also, to obtain a strength of 80 kgf/vts2, it takes 50 kgf/vts2.
% or more, it is difficult to obtain high strength.
（４）上記（４）の合金は、硬化深度が浅いために焼入
れが難しいα＋β系Ｔｉ合金であるので、油井のアクセ
サリ−用素材として最も多用される厚肉製品において、
１００ ｋｇｆ／ ｍ”以上の強度を均一に得ることが
困難である。(4) The alloy mentioned in (4) above is an α+β Ti alloy that is difficult to harden due to its shallow hardening depth.
It is difficult to uniformly obtain a strength of 100 kgf/m'' or more.
従って、この発明の目的は、高濃度のＨ，ＳやＳｏを含
む厳しい環境下で、十分な耐食性および耐ＳＣＣ性を有
する高強度β系チタン合金を提供することにある。Therefore, an object of the present invention is to provide a high-strength β-based titanium alloy that has sufficient corrosion resistance and SCC resistance in a harsh environment containing high concentrations of H, S, and So.
［課題を解決するための手段］ 第１の発明は、 ＡＱ：０．５から２．Ｏｗｔ、１未満。[Means to solve the problem] The first invention is AQ: 0.5 to 2. Owt, less than 1.
Ｍｏ：５．Ｏから１０．Ｏｖｔ、％、 ｖ ；８から１２ｗｔ０％、 Ｚｒ：３から（３ｖｔ、％、 但し、Ｍｏ、ＶおよびＺｒは、下記関係式％式％） を満足する。Mo:5. O to 10. Ovt, %, v; 8 to 12wt0%, Zr: From 3 (3vt, %, However, Mo, V and Zr are expressed by the following relational formula (%) satisfy.
残り、Ｔｉおよび不可避的不純物。The remainder is Ti and unavoidable impurities.
但し、前記不可避的不純物としての、０、およびＦｅの
それぞれの含有量は、
０については、０．４すｔ、％以下。However, the content of each of 0 and Fe as the unavoidable impurities is 0.4st% or less for 0.
Ｆｅについては、１．Ｏｗｔ、Ｚ以下。Regarding Fe, 1. Owt, below Z.
からなることに特徴を有し、
第２の発明は、前記合金に、 ５ｗｔ、％のＮｂおよび
／または５ｗｔ、％のＴａが、更に付加的に含有され、
且つ、Ｍｏ、Ｖ、Ｚｒ、ＮｂおよびＴａは、下記関係式
％式％）
を満足することに特徴を有するものである。The second invention is characterized in that the alloy further additionally contains 5 wt.% Nb and/or 5 wt.% Ta,
Moreover, Mo, V, Zr, Nb, and Ta are characterized by satisfying the following relational expression (%).
本願発明者等は、高濃度のＨ，ＳやＳｏを含む厳しい環
境下で、十分な耐食性および耐ＳＣＣ性を有する高強度
チタン合金を得べく、鋭意研究を重ねた。この結果、次
の知見を得た。即ち、Ｍ。The inventors of the present application have conducted intensive research in order to obtain a high-strength titanium alloy that has sufficient corrosion resistance and SCC resistance in a harsh environment containing high concentrations of H, S, and So. As a result, the following findings were obtained. That is, M.
を含むＴｉ合金の素材について、これを、油井用材料の
使用温度域である２００から２５０℃の温度域に１４４
０時間保持した後、その硬度を調べた。この結果、 β
相が不安定のα＋β系Ｔｉ合金の素材は、使用中に硬度
変化が生じるために、油井用材料として使用するには問
題がある。これに対して、β相が安定なβ系チタン合金
は１時効処理によって高強度が容易に得られ且つ硬化深
度が深いので、強度面で、α＋β系Ｔｉ合金より有利で
ある。Regarding the Ti alloy material containing
After holding for 0 hours, the hardness was examined. As a result, β
Since the α+β Ti alloy material, which has an unstable phase, undergoes hardness changes during use, it is problematic to use it as an oil well material. On the other hand, a β-based titanium alloy with a stable β phase can easily obtain high strength by one aging treatment and has a deep hardening depth, so it is more advantageous than an α+β-based Ti alloy in terms of strength.
この発明は、上述した知見に基づきなされ！已ものであ
る。This invention was made based on the above-mentioned knowledge! It's a thing.
次に、この発明のＴｉ合金の化学成分組成を、上述のよ
うに限定した理由について以下に述べる。Next, the reason why the chemical composition of the Ti alloy of the present invention is limited as described above will be described below.
（１）ＡＱ：
ＡＱは、時効の際、α相などの二次析出相を析出し、強
度の上昇に寄与する。この効果は、ＡＱの含有量がＱ、
５ｗｔ、対以上で認められる。一方、Ａｎの含有量が２
ｔｉｔ、１以上では、耐ＳＣＣ性が劣化する。従って、
ＡＱ含有量はＱ 、 ５ ｗｔ、％以上２ｗｔ、Ｚ未満
に限定すべきである。(1) AQ: AQ precipitates secondary precipitated phases such as α phase during aging and contributes to an increase in strength. This effect is due to the AQ content Q,
5wt, permitted in pairs or more. On the other hand, the content of An is 2
tit, 1 or more, the SCC resistance deteriorates. Therefore,
The AQ content should be limited to more than Q, 5 wt,% and less than 2 wt, Z.
Ａ Ｑの添加効果を調べるために、以下の試験を行った
。即ち、この発明の範囲内の成分組成からなるチタン合
金に異なる量のＡＱを添加し、このチタン合金の各々を
アーク溶解によって、長さ１３０ｍｍ、幅４０画、厚さ
２０ｎｎの寸法のインゴットとし、 １０５０℃にて熱
間鍛造して長さ１７０１、幅３０ｎｎ、厚さ２０ｏｍの
寸法のスラブとした。In order to investigate the effect of adding AQ, the following test was conducted. That is, different amounts of AQ were added to titanium alloys having compositions within the range of the present invention, and each of these titanium alloys was melted by arc melting to form ingots with dimensions of 130 mm in length, 40 strokes in width, and 20 nm in thickness. It was hot forged at 1050°C to form a slab with dimensions of 1701 mm in length, 30 nn in width, and 20 om in thickness.
次いで、このスラブに対して９００℃で最終熱間圧延を
施して、厚さ６ｍの熱延板とし、β相領域で３０分間保
持し、次いで、水冷の溶体化処理および５５０℃の温度
域で５時間、時効処理を施し、試験片を切り出した。そ
して、これらの試験片をビッカース硬さ試験に供して、
脆化相の析出に伴なうＡＱの影響について調べた。この
結果を第１図に示す。第１図において、Ｏ印は、ＴＬ−
９Ｍ。Next, this slab was subjected to a final hot rolling at 900°C to form a hot rolled plate with a thickness of 6 m, held in the β phase region for 30 minutes, and then subjected to water cooling solution treatment and a temperature range of 550°C. After aging for 5 hours, test pieces were cut out. Then, these specimens were subjected to Vickers hardness test,
The influence of AQ on the precipitation of the embrittlement phase was investigated. The results are shown in FIG. In Figure 1, the O mark is TL-
9M.
−６，５Ｖ−５Ｚｒ−０，２Ｆｅ−０，２（０）からな
るチタン合金であり１時効処理条件は、５５０’Ｘ５ｈ
ｒである。そして、・印は、０印と同一の合金であり、
時効処理条件は、４００℃Ｘ５ｂｒである。It is a titanium alloy consisting of -6,5V-5Zr-0,2Fe-0,2(0), and the aging treatment conditions are 550' x 5 h.
It is r. And, the mark is the same alloy as the mark 0,
The aging treatment conditions are 400°C x 5br.
第１図から明らかなように、５５０℃で時効処理を施し
たチタン合金Ｏは、ＡＱ添加に伴い硬度が上昇した。こ
れに′より、ＡＱは、α相の析出により強度の上昇に寄
与することが分る。一方、脆化領域にある、４００℃で
時効処理を行ったチタン合金・は、ＡＱ添加に伴い硬度
が低下した。これにより、ＡＱ添加が脆化相の抑制に対
しても効果を有することが分る。As is clear from FIG. 1, the hardness of titanium alloy O subjected to aging treatment at 550° C. increased with the addition of AQ. This shows that AQ contributes to an increase in strength through the precipitation of α phase. On the other hand, the hardness of the titanium alloy aged at 400° C., which is in the embrittlement region, decreased with the addition of AQ. This shows that the addition of AQ is also effective in suppressing the brittle phase.
（２） Ｍｏ：
Ｍｏは、 β相を安定化させる元素で油井環境及び地熱
環境中での耐食性を付与するものである。(2) Mo: Mo is an element that stabilizes the β phase and provides corrosion resistance in oil well environments and geothermal environments.
しかしながら、ＭＯの含有量が、１０ｗｔ、％を超える
と、コスト及び溶解性が悪化する。一方、Ｍ。However, when the MO content exceeds 10 wt%, cost and solubility deteriorate. On the other hand, M.
の含有量が５ｗｔ、１未満では所望の耐食性が得られな
い。従って、Ｍｏ含有量は、５ｗｔ、１以上、１０ｗｔ
、ｘ以下の範囲に限定すべきである。If the content is less than 5wt, 1, the desired corrosion resistance cannot be obtained. Therefore, the Mo content is 5wt, 1 or more, 10wt
, x or less.
（３）Ｚｒ：
Ｚｒは、Ｔｉに対し、全率固溶して強化に寄与する。ま
た、ＡＱ共存下での高硫化水素分圧とＳ。(3) Zr: Zr completely forms a solid solution with Ti and contributes to strengthening. In addition, high hydrogen sulfide partial pressure and S in the coexistence of AQ.
を含む油井環境で、耐ＳＣＣ性の向上に寄与する。Contributes to improved SCC resistance in oil well environments including
しかし、Ｚｒの含有量が３ｗｔ、１未満では耐ＳＣＣの
向上効果が得られない。一方、Ｚｒの含有量が６ｗｔ、
％を超えるとコスト高及び脆化の原因となる。However, if the Zr content is less than 3 wt.1, the effect of improving SCC resistance cannot be obtained. On the other hand, the Zr content is 6wt,
%, it causes high cost and embrittlement.
従って、 Ｚｒの含有量は３ｗｔ、１以上６ｗｔ、％
以下に限定すべきである。Therefore, the Zr content is 3wt, 1 or more 6wt, %
It should be limited to:
（４）Ｖ：
■は、油井環境及び地熱環境中での耐食性に大きくは寄
与しないが、全率固溶型のβ安定化元素であるため、β
単相を得る際のβ相生成元素として、及び延性を改善す
るために添加される。(4) V: Although it does not significantly contribute to corrosion resistance in oil well environments and geothermal environments, it is a β-stabilizing element that is completely solid solution.
It is added as a β phase forming element when obtaining a single phase and to improve ductility.
Ｔｉ−９Ｍｏ−５Ｚｒ−０，２Ｆｅ−０，２（０）から
なるチタン合金にＶを添加し、９００℃で最終熱間圧延
を施し、β相領域で３０分保持後、水冷の溶体化処理お
よび５５０℃の温度域で５時間、時効処理を施して試駆
片を調製し、これらの試験片に対して室温において延性
を調べた。この結果を第２図に示す。第２図から明らか
なように２ｖを添加することによって、室温における延
性が改善されることがわかる。しかしながら、■の含有
量が８ｗｔ、１未満では、伸びが小さく、一方、■の含
有量が１２ｗｔ、％を超えるとコストおよび耐食性の点
から好ましくない、また、β系チタン合金において、そ
のβ相生成能が、 １６ｗｔ、％）Ｍｏ＋ ５／７（Ｖ
＋Ｚｒ）の範囲にあるものは、２３０℃で保持するとα
相などの析出がみられ、相安定性に欠ける。従って。V was added to a titanium alloy consisting of Ti-9Mo-5Zr-0,2Fe-0,2(0), subjected to final hot rolling at 900°C, held in the β phase region for 30 minutes, and then water-cooled solution treatment. Test specimens were prepared by aging in a temperature range of 550° C. for 5 hours, and the ductility of these test specimens was examined at room temperature. The results are shown in FIG. As is clear from FIG. 2, the addition of 2v improves the ductility at room temperature. However, if the content of ■ is less than 8wt, 1, the elongation is small, while if the content of The production capacity is 16wt, %)Mo+ 5/7(V
+Zr) When kept at 230℃, α
Precipitation of phases is observed, and phase stability is lacking. Therefore.
■の含有量は、８ｗｔ、％以上１２ｔｉｔ、Ｚ以下の範
囲で。The content of (2) is in the range of 8 wt, % or more and 12 tit, Z or less.
１６ｗｔ、％≦Ｍｏ＋ ５／７（Ｖ＋Ｚｒ）を満たす範
囲に限定すべきである。It should be limited to a range that satisfies 16wt, %≦Mo+5/7(V+Zr).
（５）Ｎｂ、Ｔａ：
ＮｂおよびＴａは、油井および地熱環境中での耐食性を
改善する。しかしながら、ＮｂおよびＴａの含有量が５
ｗｔ、％を超えると、耐食性には寄与するがコストの点
で好ましくない。従って、ＮｂおよびＴａは、 β相生
成元素として補助的に使用されるべきであり、Ｎｂの含
有量は５ｗｔ、％以下、Ｔａの含有量は５ｗｔ、％以下
に限定する。但し１組織の安定性の点からＮｂおよびＴ
ａの含有量は、１６ｗｔ、％≦Ｍｏ＋５／７（Ｖ＋Ｚｒ
）＋３１５（Ｎｂ＋Ｔａ）を満たす範囲に限定すべきで
ある。(5) Nb, Ta: Nb and Ta improve corrosion resistance in oil well and geothermal environments. However, the content of Nb and Ta is 5
If it exceeds wt.%, it contributes to corrosion resistance but is not preferable in terms of cost. Therefore, Nb and Ta should be used supplementarily as β phase forming elements, and the Nb content is limited to 5 wt.% or less, and the Ta content is limited to 5 wt.% or less. However, from the viewpoint of stability of the structure, Nb and T
The content of a is 16wt, %≦Mo+5/7(V+Zr
)+315(Nb+Ta).
第３図は、ダウンホールエージングによって、組織変化
を起さない領域および、本発明範囲を、β相生成能を持
つ合金元素の含有量との関係で示したグラフである。第
３図に示したＴｉ合金のＡＱ含有量は、 いずれも０
、５ ｗｔ、％以上２ｗｔ、ｘ未満の範囲にある。FIG. 3 is a graph showing the region where no structural changes occur due to downhole aging and the range of the present invention in relation to the content of alloying elements having β-phase forming ability. The AQ content of the Ti alloys shown in Figure 3 is 0.
, 5 wt,% or more and less than 2 wt, x.
第３図から明らかなように、ダウンホールエージングを
生じない領域は、 １６ｗｔ、％≦Ｍｏ＋５／７（Ｖ＋
Ｚｒ）＋３１５（Ｎｂ＋Ｔａ）を満たす範囲にあること
がわかる。As is clear from Fig. 3, the area where downhole aging does not occur is 16wt, %≦Mo+5/7(V+
It can be seen that the range satisfies Zr)+315(Nb+Ta).
（６）Ｏ：
０は、合金中に不可避的に含まれるが、０．４ｗｔ、気
を超えると延性が劣化する。従って、○の含有量は、
０．４ｗｔ０％以下とすべきである。(6) O: O is unavoidably contained in the alloy, but if it exceeds 0.4 wt, the ductility deteriorates. Therefore, the content of ○ is
It should be 0.4wt0% or less.
（７）Ｆｅ：
共析型β相安定化元素であるＦｅは、合金中に不可避的
に含まれる。Ｆｅは、高いβ相生成能を有し強度の上昇
に寄与する。しかしながら、Ｆｅの含有量が１ｗｔ、％
を超えると耐食性が劣化する。(7) Fe: Fe, which is a eutectoid β-phase stabilizing element, is inevitably included in the alloy. Fe has a high β-phase generation ability and contributes to an increase in strength. However, the Fe content is 1wt%
Corrosion resistance deteriorates when it exceeds.
従って、Ｆｅの含有量は、１ｔｓｔ、％以下に限定すべ
きである。Therefore, the content of Fe should be limited to 1 tst,% or less.
なお、Ｆｅ以外の共析型β相安定化元素としては、Ｎｉ
、Ｃｏ、Ｃｒ、Ｗなどがあるが、これらの元素が添加さ
れると、ダウンホールエージングにより金属間化合物等
を析出して脆化を生じたり、加工性などの機械的性質が
害される。しかしながら、Ｎｉ、Ｃｏ、Ｃｒ、Ｗのすく
なくとも１種の含有量が合計で４ｗｔ、％未満であれば
耐食性、耐ＳＣＣ性に悪影響を及ぼすことはない。In addition, as eutectoid β phase stabilizing elements other than Fe, Ni
, Co, Cr, W, etc., but when these elements are added, intermetallic compounds etc. are precipitated due to downhole aging, resulting in embrittlement and mechanical properties such as workability are impaired. However, if the total content of at least one of Ni, Co, Cr, and W is less than 4 wt.%, corrosion resistance and SCC resistance will not be adversely affected.
次に、この発明を実施例により更に詳細に説明する。Next, the present invention will be explained in more detail with reference to Examples.
［実施例１］
第１表に示す、この発明の範囲内の成分組成を有する本
発明合金Ｎａ １〜２５およびこの発明の範囲外の成分
組成を有する比較合金Ｎα２６〜３５の各々をアーク溶
解によって、長さ１３０ｍｍ、Ｉ［４０薗、厚さ２ｏＩ
ＩＩ１１の寸法のインゴットとし、１０５０℃にて熱間
鍛造して長さ１７０ｎｗａ、幅ｇｏｎｎ＋、厚さ２０画
の寸法のスラブとした。次いで、このスラブに対して９
００℃で最終熱間圧延を施して、厚さ６Ｉの熱延板とし
、β相領域で３０分間保持し、次いで、水冷の溶体化処
理および５５０℃の温度域で５時間１峙効処理を施し、
試験片を切り出した。[Example 1] Each of the present invention alloys Na 1 to 25 having a composition within the range of the present invention and the comparative alloys Nα26 to 35 having a composition outside the range of the present invention shown in Table 1 was melted by arc melting. , length 130mm, I[40mm, thickness 2oI
An ingot with dimensions of II11 was prepared, and hot forged at 1050° C. to obtain a slab with dimensions of 170 nwa in length, gonn+ in width, and 20 strokes in thickness. Then 9 for this slab
Final hot rolling was performed at 00°C to obtain a hot rolled sheet with a thickness of 6I, held in the β phase region for 30 minutes, and then subjected to water cooling solution treatment and 1 side effect treatment in a temperature range of 550°C for 5 hours. alms,
A test piece was cut out.
これらの試験片について、引張試験を実施して機械的性
質を調べた。また時効熱処理を施した後、硬度試験を行
って相安定性を調べた。そして、四点曲げ試験を実施し
て耐食性、耐ＳＣＣ性を調べた。その結果を第１表に併
せて示す。These test pieces were subjected to a tensile test to examine their mechanical properties. In addition, after aging heat treatment, a hardness test was conducted to examine phase stability. Then, a four-point bending test was conducted to examine corrosion resistance and SCC resistance. The results are also shown in Table 1.
引張試験による機械的性質については、降伏強度を示し
た。相安定性の評価は、２３２℃で１４４０時間時効熱
処理を施した後、硬度の変化しないものを０．硬度の変
化するものを×とした。As for mechanical properties by tensile test, yield strength was shown. Evaluation of phase stability was performed by aging heat treatment at 232°C for 1440 hours, and then determining whether the hardness remained unchanged or 0. Those whose hardness changed were marked as ×.
四点曲げ試験は、第４図に示すように、試験片の四点に
所定の荷重をかけた後、腐食環境に浸漬し、割れの有無
および腐食状態を評価するものである。この実施例にお
いて実施した四点曲げ試験の腐食環境は、２３２℃、９
０ａｔｍＨ２Ｓ−５５ａｔｏ＋Ｃｏ、、２５％ＮａＣＱ
＋１ｇ／＋２３’とし、オートクレーブ中で６０日間試
験を行なった。In the four-point bending test, as shown in FIG. 4, a predetermined load is applied to four points on a test piece, and then the test piece is immersed in a corrosive environment to evaluate the presence or absence of cracks and the state of corrosion. The corrosive environment for the four-point bending test conducted in this example was 232°C, 9
0atmH2S-55ato+Co, 25%NaCQ
+1 g/+23', and the test was conducted in an autoclave for 60 days.
耐ＳＣＣ性の評価は、割れ無しを○、割れ発生を×で示
した。また、耐食性の評価は、腐食速度が０．５＋ｎｍ
／年未満をＱ、０ 、５ ｎｗｎ ／年以上を×で示し
た６
第１表から明らかなように１本発明合金は、何れも耐食
性および耐ＳＣＣ性に優れ、しかも、高強度を有してい
る。In the evaluation of SCC resistance, no cracking was indicated by ◯, and cracking was indicated by ×. In addition, the evaluation of corrosion resistance shows that the corrosion rate is 0.5+nm.
Less than / year is shown by Q, 5 nwn / year or more is shown by ing.
これに対して、ＡＱの含有量がこの発明の範囲から外れ
て高い比較合金Ｎａ３１は耐ＳＣＣ性が悪かった。Ａｆ
ｌが添加されていない比較合金Ｎα３３は強度が低かっ
た。Ｍｏの含有量がこの発明の範囲から外れて低い比較
合金Ｎα２９，３０．およびＭｏが添加されていない比
較合金Ｎα３２は耐食性が悪かった。 Ｚｒの含有量が
この発明の範囲から外れて低いＮα３５は、耐ＳＣＣ性
が悪かった。On the other hand, the comparative alloy Na31, which had a high AQ content outside the range of the present invention, had poor SCC resistance. Af
Comparative alloy Nα33 to which l was not added had low strength. Comparative alloys Nα29, 30. Comparative alloy Nα32 to which Mo was not added had poor corrosion resistance. Nα35 with a low Zr content outside the range of the present invention had poor SCC resistance.
ＡＱおよびＭｏの含有量がこの発明の範囲内であっても
ＡＱ、Ｍｏ、ＶおよびＺｒの含有量が１６≦Ｍｏ＋５／
７（Ｖ＋Ｚｒ）の範囲から外れて低い比較合金Ｎα２６
．２７および２８は、室温でβ単相が得られないか、ま
たは、相安定性が悪かった。 Ｆｅの含有量がこの発明
の範囲を外れて高い比較合金Ｎａ３４は、高強度ではあ
るが、耐食性が悪かった。Even if the content of AQ and Mo is within the range of this invention, the content of AQ, Mo, V and Zr is 16≦Mo+5/
Comparative alloy Nα26 that is outside the range of 7(V+Zr)
．． In samples 27 and 28, a β single phase could not be obtained at room temperature or the phase stability was poor. Comparative alloy Na34, which had a high Fe content outside the range of the present invention, had high strength but poor corrosion resistance.
［比較例］
第２表に示すこの発明の範囲外の成分組成を有する比較
Ｔｉ合金Ｎα１〜５、および、Ｎｊ、、Ｆｅベースの比
較合金Ｎα６から、上述した実施例と同一条件に従って
試験片を切り出し、これらの試験片の各々について、引
張試験を実施して機械的性質を調べた。この結果を第２
表に示す。また、これらの試験片の各々について四点曲
げ試験を、第３表に示すＡ−Ｅの５種類の異なる環境の
試験条件下でオートクレーブ中で３０日間実施して、耐
食性および耐ＳＣＣ性について調べた。その結果を第２
表に示す。耐食性および耐ＳＣＣ性の評価は、割れ無し
を０、割れ発生を×で示した。また、各合金の母相組織
を第２表に併せて示す。[Comparative Example] Test pieces were prepared from the comparative Ti alloys Nα1 to Nα5 having component compositions outside the range of the present invention shown in Table 2, and the Nj, Fe-based comparative alloy Nα6 according to the same conditions as in the above-mentioned Examples. Each of these test pieces was cut out and subjected to a tensile test to examine its mechanical properties. This result is the second
Shown in the table. In addition, a four-point bending test was conducted on each of these test pieces in an autoclave for 30 days under the test conditions of five different environments A to E shown in Table 3 to investigate the corrosion resistance and SCC resistance. Ta. The result is the second
Shown in the table. In the evaluation of corrosion resistance and SCC resistance, 0 indicates no cracking, and × indicates cracking. Table 2 also shows the matrix structure of each alloy.
第２表から明らかなように、比較合金Ｎｏ １およびＮ
α６は降伏応力および破断強度とも１００ｋｇｆ／ＩＩ
！１１２以下の低い数値を示した。比較合金Ｎα２〜５
は何れもＳｏを含む高温の腐食環境で割れが発生した。As is clear from Table 2, comparative alloys No. 1 and N
α6 is both yield stress and breaking strength of 100kgf/II
! It showed a low value of 112 or less. Comparative alloy Nα2~5
In both cases, cracking occurred in a high-temperature corrosive environment containing So.
［発明の効果］
以上説明したように、この発明によれば、高濃度のＨ２
ＳやＳｏを含む厳しい環境下で、 十分な耐食性および
耐ＳＣＣ性を有することは勿論、高い強度を有するβ系
チタン合金を得ることができるといった有用な効果がも
たらされる。[Effects of the Invention] As explained above, according to the present invention, high concentration H2
This provides useful effects such as being able to obtain a β-based titanium alloy that not only has sufficient corrosion resistance and SCC resistance but also has high strength in a harsh environment containing S and So.
・・試験片。··Test pieces.
Claims (1)
足する。 残り、Ｔｉおよび不可避的不純物、 但し、前記不可避的不純物としての、Ｏ、 およびＦｅのそれぞれの含有量は、 Ｏについては、０．４ｗｔ．％以下、 Ｆｅについては、１．０ｗｔ％以下。 からなることを特徴とする、耐食性および耐応力腐食割
れ性に優れた高強度β系チタン合金。 ２ 前記合金は、５ｗｔ．％のＮｂおよび／または５ｗ
ｔ．％のＴａを、更に付加的に含有し、且つ、Ｍｏ，Ｖ
，Ｚｒ，ＮｂおよびＴａは、下記関係式 １６ｗｔ％≦Ｍｏ＋（５）／（７）（Ｖ＋Ｚｒ）＋（３
）／（５）（Ｎｂ＋Ｔａ）を満足することを特徴とする
、請求項１記載のチタン合金。[Claims] 1 Al: 0.5 to 2.0wt. Less than Mo: 5.0 to 10.0wt. %, V: 8 to 12 wt. %, Zr: 3 to 6 wt. %, however, Mo, V and Zr are expressed by the following relational expression 16wt. %≦Mo+(5)/(7)(V+Zr) is satisfied. The remaining content is Ti and unavoidable impurities. However, the respective contents of O and Fe as the unavoidable impurities are as follows: For O, the content is 0.4 wt. % or less, and for Fe, 1.0wt% or less. A high-strength β-based titanium alloy with excellent corrosion resistance and stress corrosion cracking resistance. 2 The alloy has a weight of 5 wt. %Nb and/or 5w
t. % Ta, and Mo, V
, Zr, Nb and Ta are determined by the following relational expression 16wt%≦Mo+(5)/(7)(V+Zr)+(3
)/(5)(Nb+Ta).
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10501388 | 1988-04-27 | ||
| JP63-105013 | 1988-04-27 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH02138429A true JPH02138429A (en) | 1990-05-28 |
| JP2623826B2 JP2623826B2 (en) | 1997-06-25 |
Family
ID=14396185
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP10890889A Expired - Lifetime JP2623826B2 (en) | 1988-04-27 | 1989-04-27 | High-strength β-based titanium alloy with excellent corrosion resistance and stress corrosion cracking resistance |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2623826B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110983102A (en) * | 2019-12-02 | 2020-04-10 | 中国石油天然气集团有限公司 | Titanium alloy oil pipe and manufacturing method thereof |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2005005677A1 (en) * | 2003-07-15 | 2005-01-20 | Minoru Fumoto | Titanium alloy and eyeglass frame excelling in spring characteristic |
-
1989
- 1989-04-27 JP JP10890889A patent/JP2623826B2/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110983102A (en) * | 2019-12-02 | 2020-04-10 | 中国石油天然气集团有限公司 | Titanium alloy oil pipe and manufacturing method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2623826B2 (en) | 1997-06-25 |
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