JPS61157626A - Manufacture of ferritic-austenitic two-phase stainless steel - Google Patents
Manufacture of ferritic-austenitic two-phase stainless steelInfo
- Publication number
- JPS61157626A JPS61157626A JP27600384A JP27600384A JPS61157626A JP S61157626 A JPS61157626 A JP S61157626A JP 27600384 A JP27600384 A JP 27600384A JP 27600384 A JP27600384 A JP 27600384A JP S61157626 A JPS61157626 A JP S61157626A
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- Prior art keywords
- less
- stainless steel
- strength
- corrosion resistance
- heat treatment
- 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.)
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/004—Heat treatment of ferrous alloys containing Cr and Ni
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Heat Treatment Of Steel (AREA)
Abstract
Description
【発明の詳細な説明】
「発明の目的」
本発明はフェライト・オーステナイト２相ステンレス鋼
の製造方法に係り、フェライト・オーステナイト２相ス
テンレス鋼の強度を時効熱処理によって向上せしめ、靭
性および耐食性を損うことなしに強度増加を得しめよう
とするものである。[Detailed Description of the Invention] "Object of the Invention" The present invention relates to a method for producing a ferritic-austenitic duplex stainless steel, which improves the strength of the ferritic-austenitic duplex stainless steel by aging heat treatment, thereby reducing toughness and corrosion resistance. This is an attempt to increase strength without causing any damage.
産業上の利用分野
フェライト・オーステナイト２相ステンレス鋼の製造技
術。Industrial application technology for manufacturing ferritic-austenitic duplex stainless steel.
従来の技術
フェライト・オーステナイト２相ステンレス鋼はその高
強度と優れた耐食性、耐応力腐食割れ性を有することが
近年においては炭酸ガス油井をはじめとするサワーガス
油井用鋼管として使用されつつある。ところが、このよ
うな油井環境の苛酷化とともに油井の高深度化に伴って
、より高強度で靭性の優れた２相ステンレス鋼が望まれ
ている。BACKGROUND OF THE INVENTION Ferrite-austenite duplex stainless steel has high strength, excellent corrosion resistance, and stress corrosion cracking resistance, and has recently been used as steel pipes for sour gas oil wells including carbon dioxide oil wells. However, as oil well environments become more severe and oil wells become deeper, duplex stainless steels with higher strength and superior toughness are desired.
然してこのサワーガス油井管用２相ステンレス鋼として
は、Ｃｒを２０〜２８ｗｔ％、Ｍｏ ： ２〜４ｗｔ％
を含み、フェライト相の体積率が４０〜６０％である鋼
種が耐食性、耐応力腐食割れ性により優れている点から
、さらにＮ−ｔ−０，１〜０．３ｗｔ％添加した鋼種は
耐食性と共に高強度であることから最適な成分系とされ
ている。However, this duplex stainless steel for sour gas oil country pipes contains 20 to 28 wt% Cr and 2 to 4 wt% Mo.
Steel types with a ferrite phase volume fraction of 40 to 60% are superior in corrosion resistance and stress corrosion cracking resistance, and steel types with an additional Nt-0.1 to 0.3 wt% have excellent corrosion resistance as well as corrosion resistance. It is considered to be the most suitable component system due to its high strength.
なおこのような２相ステンレスの高強度化に関しては、
■ フェライト相の体積率を７０〜９０％と多くする方
法。In order to increase the strength of such two-phase stainless steel, there are two methods: (1) increasing the volume fraction of the ferrite phase to 70 to 90%;
■ 冷間加工による方法。■ Cold working method.
■ 合金元素添加による方法
■ 時効熱処理による方法
があり、例えば特開昭５２−３６５１２号、特公昭５１
−２９８４８号、同５９−７３４７号、同５６−２１４
５号、同５０−４６０６号、特開昭５９−７０７１９号
などに示されている。■ A method by adding alloying elements ■ A method by aging heat treatment.
-29848, 59-7347, 56-214
No. 5, No. 50-4606, and Japanese Unexamined Patent Publication No. 59-70719.
発明が解決しようとする問題点・
然し前記したような従来のものにおいてもそれぞれに問
題点を有し、即ち上記した一般的な２相ステンレス鋼に
おいてはその溶体化熱処理ままの強度が０．２％耐力で
５０〜６０ｋｇ／顛２と高く、オーステナイト系ステン
レス鋼の強度に対し略２倍の強度を有するものの油井管
の強度レベルの１つである８０ＫＳｉ Ｃ０，２％耐
力で５７ｋｇ／１２以上）を超える製品を安定して製造
することが容易でない。Problems to be Solved by the Invention However, each of the conventional stainless steels described above has its own problems, namely, the strength of the above-mentioned general duplex stainless steel after solution heat treatment is 0.2. Although it has a high % proof stress of 50 to 60 kg/2, and has approximately twice the strength of austenitic stainless steel, it is one of the strength levels of oil country tubular goods (80KSi C0.2% proof stress of 57 kg/12 or more) It is not easy to stably manufacture products that exceed
又前記した■の方法は、強度および熱間加工性の上では
有効であるが、靭性および耐食性に問題がある。Further, the method (2) described above is effective in terms of strength and hot workability, but has problems in toughness and corrosion resistance.
然して前記■のものは、０．２％耐力１００ｋｇ／朋２
以上の高強度が得られるが、靭性の低下と耐応力腐食割
れ性が劣化する。又この方法は冷間加工が困難な形状の
製品（例えば溶接部を有するものや、複雑な形状に熱間
成形されたもの）への応用ができない。However, the one mentioned above has a 0.2% yield strength of 100kg/Tomo2
Although the above-mentioned high strength can be obtained, the toughness and stress corrosion cracking resistance deteriorate. Furthermore, this method cannot be applied to products with shapes that are difficult to cold-work (for example, products with welded parts or products hot-formed into complex shapes).
■の方法によるものは、熱間加工性の劣化と、靭性およ
び耐食性の劣化が避は得ない。即ちＳｉ。When using method (2), deterioration in hot workability, toughness and corrosion resistance are inevitable. That is, Si.
Ｍｎ ＋ Ｍｏ ＋ Ｗ等の固溶強化元素を多く添加す
ると熱間加、工性を低下させるσ相の析出を促進する。Addition of a large amount of solid solution strengthening elements such as Mn + Mo + W promotes precipitation of σ phase which reduces hot workability.
一方ＴＩ ＋ Ｚｒ ＋Ｈｆ ＋ Ｖ ＩＮｂ 、Ｔａ
およびＡ１などを添加するとフェライト中に炭窒化物が
析出し、強度は上昇するものの、フェライト相を著しく
脆化させ、耐孔食性も劣化する。On the other hand, TI + Zr + Hf + V INb , Ta
When A1 and the like are added, carbonitrides precipitate in the ferrite, and although the strength increases, the ferrite phase becomes significantly brittle and the pitting corrosion resistance also deteriorates.
更に■によるものは、σ相脆化および４７５℃脆化によ
り硬化させる方法であり、強度や耐摩耗性は向上するが
著しい脆化を伴い、耐食性も劣化するごととなる。Furthermore, method (2) is a method of hardening by σ-phase embrittlement and 475° C. embrittlement, which improves strength and wear resistance but causes significant embrittlement and deteriorates corrosion resistance.
「発明の構成」
問題点を解決するための手段
Ｃ：０．０２ｗｔ％以下、 Ｓｉ ： １．０ｗｔ％以
下、Ｍｎ ： １．５ｗｔ％以下、 Ｃｒ： ２１〜
２８ｗｔ％、Ｎｉ：：３〜３ｗｔ％、 ＭＯ：１〜
４ｉｎｔ％、Ｎ ： ０．１〜０．３ｗｔ％、 Ｃｕ：
２ｗｔ％以下、Ｗ：２ｗｔ％以下、 へ１：０．０
２袈ｔ％以下、Ｔｉ、Ｖ、Ｎｂ、Ｔａ ：何れも０．１
ｔｖｔ％以下、Ｚｒ、Ｂ：何れも０．０１ｗｔ％以下、
Ｐ：０．０２ｗｔ％以下、 Ｓ ： ０．００５ｗｔ％
以下を含有した鋼を１０００〜１１５０°Ｃで溶体化熱
処理後、４５０〜５００″Ｃで３０〜１２０分の時効熱
処理することを特徴とするフェライト・オーステナイト
２相ステンレス鋼の製造方法。"Structure of the invention" Means for solving the problem C: 0.02wt% or less, Si: 1.0wt% or less, Mn: 1.5wt% or less, Cr: 21~
28wt%, Ni::3~3wt%, MO:1~
4 int%, N: 0.1 to 0.3 wt%, Cu:
2wt% or less, W: 2wt% or less, to 1:0.0
2 t% or less, Ti, V, Nb, Ta: All 0.1
tvt% or less, Zr, B: all 0.01wt% or less,
P: 0.02wt% or less, S: 0.005wt%
A method for producing a ferritic-austenitic duplex stainless steel, which comprises solution heat treating a steel containing the following at 1000 to 1150°C and then subjecting it to aging heat treatment at 450 to 500″C for 30 to 120 minutes.
作用
ｉｖｔ％（以下単に％という）でＣを０．０２％以下と
することにより耐食性を確保し、Ｓｉを１．０％以下、
Ｍｎを１．５％以下とすることによって熱間加工性およ
び靭性が確保される。Corrosion resistance is ensured by setting C to 0.02% or less in action ivt% (hereinafter simply referred to as %), and Si to 1.0% or less.
By controlling Mn to 1.5% or less, hot workability and toughness are ensured.
Ｃｒ２１％以上で耐食性が得られ、又２８％以下として
熱間加工性を得しめる。Ｎｉ３％以上で耐食性が確保さ
れ、又８％以下とすることによってフェライト相体積率
を適切に得しめる。ｌ′ＩＯを１％以上として耐孔食性
が得られ、又４％以下として熱エライト体積率を適切に
得しめる。Corrosion resistance is obtained when Cr is 21% or more, and hot workability is obtained when Cr is 28% or less. Corrosion resistance is ensured when the Ni content is 3% or more, and an appropriate ferrite phase volume fraction is obtained when the Ni content is 8% or less. Pitting corrosion resistance can be obtained by setting l'IO to 1% or more, and an appropriate thermoelite volume fraction can be obtained by setting l'IO to 4% or less.
１０００〜１１５０℃で溶体化熱処理してから４５０〜
５００℃で３０〜１２０分の時効熱処理することにより
均一な熱処理をなし、第一段階の硬化を図ると共に脆化
をなからしめる。After solution heat treatment at 1000~1150℃, 450~
Aging heat treatment at 500° C. for 30 to 120 minutes provides uniform heat treatment, achieves the first stage of hardening, and eliminates embrittlement.
実施例
上述したような本発明について更に説明すると、本発明
はサワーガス油井用鋼管などに用いられるステンレス鋼
として、窒素を含有し、フェライト体積率が４０〜６０
％であるフェライト・オーステナイト２相ステンレス鋼
の強度を靭性及び耐食性を損なうことなく向上させる方
法として、熱間加工後あるいは冷間加工後、１０００〜
１１５０°Ｃの温度で溶体化熱処理し、その後４５０〜
５００℃の温度範囲で２時間以内の時効熱処理を施する
ことを特徴とするものである。EXAMPLE To further explain the present invention as described above, the present invention is a stainless steel used for steel pipes for sour gas oil wells, etc., which contains nitrogen and has a ferrite volume fraction of 40 to 60.
% of ferritic-austenitic duplex stainless steel without impairing its toughness and corrosion resistance.
Solution heat treatment at a temperature of 1150 °C, then 450 ~
It is characterized in that aging heat treatment is performed within 2 hours at a temperature range of 500°C.
即ち本発明者等は、２相ステンレス鋼の高強度化の方法
としては、既に述べたような■〜■の方法があるが、油
井管用２相ステンレス鋼として求められる特性から、■
のフェライト体積率の増加、冷間加工、合金元素添加に
よる方法には問題があるとして、■に挙げた時効熱処理
による方法について検討した結果、４５０〜５００℃で
の時効熱処理によって、靭性、耐食性、耐・応力腐食割
れ性をほとんど劣化させないで、強度を増加させること
ができることを見出した。That is, the present inventors believe that methods for increasing the strength of duplex stainless steel include methods (1) to (3) as described above, but from the characteristics required for duplex stainless steel for oil country tubular goods, (1)
Considering that there are problems with the method of increasing the ferrite volume fraction, cold working, and adding alloying elements, we investigated the method of aging heat treatment listed in (2) and found that aging heat treatment at 450 to 500°C improves toughness, corrosion resistance, It has been found that strength can be increased with almost no deterioration in resistance to stress corrosion cracking.
高Ｃｒフェライト系ステンレス鋼や、２相ステンレス鋼
を４００〜５００℃で熱処理すると、フェライト相中に
α′相が析出し、著しい脆化が生しることはよく知られ
ている。然しなから、このα相の析出に伴う脆化が生じ
る前の短時間側での時効挙動については、不明な点が多
かった。そこで、本発明者等は、４００〜６００°Ｃの
温度範囲における短時間時効挙動を調査したところ、第
１図に示すごとく、時効硬化挙動が見出された。即ち、
４００℃及び６００°Ｃでの時効硬化挙動とは異なる、
４５０ ”Ｃ及び５００℃の時効では、α′相の析出に
起因すると考えられる著しい硬化挙動の前段階に一段目
の硬化が見出され、この段階を第１図で便宜上Ｓｉａｇ
ｅ Ｉと示し、著しい硬化が進行する段階Ｓｉａｇｅ
Ｕと区別した。このＳｉａｇｅ Ｔでは、１０５０
℃溶体化熱処理材と比較して、ビッカース硬さでは２０
〜３０硬化しているにもかかわらず、第２図の衝撃試験
結果が示すように、時効後も高い靭性を保持している。It is well known that when high Cr ferritic stainless steel or duplex stainless steel is heat treated at 400 to 500°C, α' phase precipitates in the ferrite phase, resulting in significant embrittlement. However, there are many unknown points regarding the aging behavior in the short period before embrittlement occurs due to the precipitation of the α phase. Therefore, the present inventors investigated short-time aging behavior in a temperature range of 400 to 600°C, and found age hardening behavior as shown in FIG. That is,
Different age hardening behavior at 400°C and 600°C,
In aging at 450"C and 500°C, a first stage of hardening was found before the significant hardening behavior, which is thought to be caused by the precipitation of the α' phase.
e I, the stage where significant hardening progresses
Distinguished from U. In this Siage T, 1050
Compared to the solution heat treated material, the Vickers hardness is 20
Despite being hardened by ~30%, it retains high toughness even after aging, as shown by the impact test results in Figure 2.
ところが、Ｓｉａｇｅ Ｔｌでは、硬度の上昇とともに
急激に衝撃値が低下し、靭性が失われる。また引張試験
の結果においても、Ｓｉａｇｅ Ｉでは、伸び、絞り
ともに溶体化ままのものに比較してほとんど低下せず、
０．２％耐力、および引張強さはともに、５〜ｌＱｋｇ
／ｎ＋上昇することが確認された。本発明においてはこ
のような新しい知見より、Ｓｉａｇｅ Ｔが現われる
４５０〜５００°Ｃの温度範囲で、かつＳｉａｇｅ ］
Ｉの段階に至らない短時間側で時効熱処理することによ
って、靭性を損なうことなく、０．２％耐力、引張強さ
を５ ｋｇ ／ １以上増加させることが可能となった
。また、この時効熱処理を実施した後の耐食性及び耐応
力腐食割れ性は、はとんど劣化しないことも確認された
。However, in Siage Tl, as the hardness increases, the impact value rapidly decreases and toughness is lost. In addition, the tensile test results showed that Siage I showed almost no decrease in both elongation and reduction of area compared to the solution-treated product.
Both 0.2% proof stress and tensile strength are 5~1Qkg
/n+ was confirmed to increase. In the present invention, based on such new knowledge, in the temperature range of 450 to 500 ° C where Siage T appears, and Siage]
By performing the aging heat treatment in a short period of time before reaching stage I, it became possible to increase the proof stress by 0.2% and the tensile strength by 5 kg/1 or more without impairing the toughness. It was also confirmed that the corrosion resistance and stress corrosion cracking resistance after this aging heat treatment hardly deteriorated.
次に、本発明における限定条件について説明すると先ず
鋼の成分組成限定理由は以下の通りである。Next, the limiting conditions in the present invention will be explained. First, the reason for limiting the composition of steel is as follows.
Ｃは、鋼の溶製上不可避的に混入して（る元素であるが
、ｗｔ％（以下単に％という）で０．２％を超えると炭
化物を形成し、耐食性を劣化させるので０．２％以下と
した。C is an element that is unavoidably mixed during the melting process of steel, but if it exceeds 0.2% in wt% (hereinafter simply referred to as %), it forms carbides and deteriorates corrosion resistance, so 0.2 % or less.
Ｓｉ、 Ｍｎは、鋼の溶製上必要な元素であるが、いず
れもα相の析出を促進する元素であり、熱間加工性及び
靭性の点から、Ｓｉは１．０％以下、Ｍｎは１．５％以
下とする。Si and Mn are elements necessary for melting steel, but both promote the precipitation of α phase, and from the viewpoint of hot workability and toughness, Si should be 1.0% or less, and Mn should be 1.0% or less. 1.5% or less.
Ｃｒは、２１％未満では耐食性が不充分であり、２８％
を超えるとα相の析出が著しく生じ易くなり熱間加工性
上問題となるため、２１〜２８％の範囲とした。If Cr is less than 21%, corrosion resistance is insufficient;
If the content exceeds 21% to 28%, precipitation of the α phase becomes extremely likely to occur, causing problems in hot workability.
Ｎｉは、３％未満では耐食性が不充分であり、その上限
はフェライト相の体積率を左右するＣｒ、 Ｍｏ、Ｎ等
の主要元素とのバランスによって決定され、フェライト
相の体積率を４０〜６０％に保つためには８％を超えな
いことが必要であり、３〜８％の範囲とする。If Ni is less than 3%, corrosion resistance is insufficient, and the upper limit is determined by the balance with major elements such as Cr, Mo, and N, which influence the volume fraction of the ferrite phase, and the volume fraction of the ferrite phase is set to 40 to 60%. %, it is necessary not to exceed 8%, and the range is 3 to 8%.
Ｍｏは、１％未満では耐孔食性に問題があり、４％を超
えるとα相の析出を促進させるために熱間加工性が劣化
するので、１〜４％の範囲とした。When Mo is less than 1%, there is a problem in pitting corrosion resistance, and when it exceeds 4%, hot workability is deteriorated because it promotes precipitation of the α phase, so the content is set in the range of 1 to 4%.
Ｎは、耐食性の改善及び高強度を得るために０．１％以
上必要であり、０．３％を超えると造塊上問題を生じ、
またフェライト相の体積率が４０〜６０％の範囲をはず
れるために、０．３％以下とする。N is required to be 0.1% or more in order to improve corrosion resistance and obtain high strength, and if it exceeds 0.3%, problems will occur in agglomeration.
Further, since the volume fraction of the ferrite phase is out of the range of 40 to 60%, it is set to 0.3% or less.
Ｃｕ、 Ｗは、耐食性を改善するが、それぞれ２％を超
えると熱間加工性を害するので、２％以下とすることが
必要である。Cu and W improve corrosion resistance, but if each exceeds 2% they impair hot workability, so they need to be kept at 2% or less.
ＡＩは、強力な脱酸作用を持つが、０．０２％を超える
とフェライト相中に窒化物を形成し、靭性を著しく劣化
させるので、０．０２％以下とする。Al has a strong deoxidizing effect, but if it exceeds 0.02%, it forms nitrides in the ferrite phase and significantly deteriorates toughness, so the content is limited to 0.02% or less.
Ｔｉ、 Ｖ 、Ｎｂ 、Ｔａ 、Ｚｒ 、 Ｂについて
は、これらの元素は強度を増加させるが、いずれも窒化
物を形成する傾向が大であり、靭性を著しく低下させる
ため、Ｔｉ、 Ｖ 、Ｎｂ 、Ｔａは０．１％以下、Ｚ
ｒ ＋ ８は０．０１％以下とする。Regarding Ti, V, Nb, Ta, Zr, and B, although these elements increase strength, they all have a large tendency to form nitrides, which significantly reduces toughness. Ta is 0.1% or less, Z
r+8 shall be 0.01% or less.
ｐ、ｓは、鋼中に不可避的に混入してくる元素であるが
、Ｐは靭性を劣化させるために０．０２％以下、Ｓは熱
間加工性に有害であるためＯ，ＯＯ５％以下とする。P and S are elements that are inevitably mixed into steel, but P is 0.02% or less because it deteriorates toughness, and S is harmful to hot workability, so O and OO are 5% or less. shall be.
なおフェライト体積率について・は、耐食性、耐応力腐
食割れ性は、フェライト体積率が５０％前後で最も優れ
ているため、激しい腐食環境で使用される油井管として
は、４０〜６０％の範囲であることが望ましい。加えて
、フェライト体積率が４０％未満であると強度が低く、
一方６０％を超えると靭性が低下するため、１０００〜
１１５０℃で溶体化熱処理された組織においてフェライ
ト体積率は、４０〜６０％の範囲であること゛とする。Regarding the ferrite volume fraction, corrosion resistance and stress corrosion cracking resistance are best at a ferrite volume fraction of around 50%, so for oil country tubular goods used in severely corrosive environments, a range of 40 to 60% is recommended. It is desirable that there be. In addition, when the ferrite volume fraction is less than 40%, the strength is low;
On the other hand, if it exceeds 60%, the toughness decreases, so
The ferrite volume fraction in the structure subjected to solution heat treatment at 1150° C. is in the range of 40 to 60%.
又時効熱処理条件の限定理由については以下の如くであ
る。即ち温度は、本発明の構成上量も重要な点で ２相
ステンレス鋼を４７５°Ｃ脆化温度域で時効処理すると
、二段階の硬化現象が現われることを見出し、この第一
段階の硬化現象を利用して、靭性をほとんど劣化させな
いで強度を増加させることであり、二段硬化現象が明瞭
に現われる４５０〜５００℃を時効熱処理の範囲とする
。The reasons for limiting the aging heat treatment conditions are as follows. In other words, temperature is also important in terms of the composition of the present invention.It was discovered that when duplex stainless steel is aged in the 475°C embrittlement temperature range, a two-stage hardening phenomenon appears, and this first-stage hardening phenomenon The aging heat treatment is performed at a temperature of 450 to 500°C, where the two-step hardening phenomenon clearly appears.
更に時効時間の限定理由は以下の如くである。Furthermore, the reason for limiting the statute of limitations is as follows.
４５０〜５００℃の温度範囲で現われる二段階時効挙動
の第一段階の硬化は、本発明の対象とする２相ステンレ
ス鋼の成分系においては、０．５時間ですでに開始して
いることが明らかであるが、製品を均一に熱処理するた
めに０．５時間以上の時効時間が必要である。一方策二
段階の硬化が現われる時間は、特にＣｒ量が多くなると
短くなる傾向がある。時効処理時間が長くなり、第二段
階の硬化が始まると、靭性が急激に低下するが、時効時
間が２時間を超えなければ第一段階の硬化のみであり、
著しく脆化することはない。このような理由から時効時
間を０．５〜２時間とした。The first stage of hardening of the two-stage aging behavior, which occurs in the temperature range of 450 to 500°C, has already started in 0.5 hours in the composition system of the duplex stainless steel that is the object of the present invention. Obviously, an aging time of 0.5 hours or more is required to uniformly heat treat the product. On the other hand, the time required for two-stage hardening to occur tends to become shorter, especially as the amount of Cr increases. When the aging treatment time becomes longer and the second stage of hardening begins, the toughness decreases rapidly, but if the aging time does not exceed 2 hours, only the first stage of hardening will occur.
No significant embrittlement occurs. For this reason, the aging time was set to 0.5 to 2 hours.
本発明によるものの具体的な製造例について説明すると
以下の如くである。A specific manufacturing example of the product according to the present invention will be described below.
次の第１表に示す化学組成の２相ステンレス鋼を熱間押
出により製管し、１０５０℃で溶体化熱処理を施した後
、４５０〜５００℃の温度範囲で。A duplex stainless steel having the chemical composition shown in Table 1 below was made into a pipe by hot extrusion, and after being subjected to solution heat treatment at 1050°C, at a temperature range of 450 to 500°C.
０、５〜４ｈ時効処理した供試材の引張特性及びシャル
ピー衝撃試験した。Tensile properties and Charpy impact tests were conducted on test materials that had been aged for 0.5 to 4 hours.
上記した引張特性及びシャルピー衝撃試験の結果は次の
第２表の通りである。The results of the tensile properties and Charpy impact test described above are shown in Table 2 below.
即ちこの第２表の結果によれば本発明の時効熱処理によ
って、溶体化熱処理ままのものに比較して、０．２％耐
力、引張強さともに５〜１０ｋｇ／１ｍ２増加し、０．
２％耐力” ７ｋｇ ／ １１＊ ｚ以上の強度が得ら
れている。また、４５０℃ｘ４ｈの時効処理では、比較
例のものが強度は０．２％耐力、引張強さともに１０ｋ
ｇ／ｗｒ＊２以上増加しているものの、シャルピー吸収
エネルギーは著しく低下しているが、本発明の製造例で
のシャルピー吸収エネルギーは、いずれも２０ ｋｇ−
ｍ以上の高い値を示している。That is, according to the results in Table 2, the aging heat treatment of the present invention increases both the yield strength and the tensile strength by 0.2% by 5 to 10 kg/1 m2, compared to the solution heat treated one.
2% proof stress" 7kg / 11*z or more strength has been obtained. In addition, in aging treatment at 450℃ x 4 hours, the comparative example has a strength of 0.2% proof stress and a tensile strength of 10k.
Although the Charpy absorbed energy has decreased significantly, although the Charpy absorbed energy has increased by more than g/wr*2, the Charpy absorbed energy in the production examples of the present invention is 20 kg-
It shows a high value of more than m.
更に、このような製造例によるものについて、その耐食
性、耐応力腐食割れ試験の結果は、第３図に示す通りで
、時効熱処理材でも溶体化熱処理材とほぼ同等の耐食性
、耐応力腐食割れ性を有していることが明らかである。Furthermore, the results of the corrosion resistance and stress corrosion cracking tests for the products manufactured in this way are as shown in Figure 3, and the aging heat treated material has almost the same corrosion resistance and stress corrosion cracking resistance as the solution heat treated material. It is clear that it has
なおこの第３図に示すものについて説明すると、（Ａ）
は５％Ｈ２ＳＯ，液によるＪＩＳ ＧＯ５９１による
試験結果で、（［１）はＪＩＳ ＧＯ５７３、（Ｃ）
はＪ Ｉ Ｓ ＧＯ５７８による試験結果であり、又
（Ｄ）は応力腐食割れ試験としてオートクレーブ中で２
０％ＮａＣ１液中で１気圧のＨｚＳおよび９気圧のＣＯ
２ガスを吹込み４逓間の４点曲げによる試験結果を示す
ものである。In addition, to explain what is shown in this Fig. 3, (A)
is the test result according to JIS GO591 using 5% H2SO, liquid, ([1) is JIS GO573, (C)
is the test result according to JIS GO578, and (D) is the test result in an autoclave as a stress corrosion cracking test.
1 atm HzS and 9 atm CO in 0% NaCl solution
This figure shows the test results obtained by blowing 2 gases and performing 4-point bending between 4 stages.
「発明の効果」
以上説明したような本発明によるときはフェライト・オ
ーステナイト２相ステンレス鋼の強度を時効熱処理によ
って向上せしめ、靭性や耐食性を侑うことなしに好まし
い強度増加を得しめるものであるから工業的にその効果
の大きい発明である。"Effects of the Invention" According to the present invention as explained above, the strength of ferritic-austenitic duplex stainless steel is improved by aging heat treatment, and a desirable increase in strength can be obtained without compromising toughness or corrosion resistance. This invention has great industrial effects.
図面ば本発明の技術的内容を示すものであって、第１図
は２和ステンレス鋼の４００〜６００°Ｃにおける短時
間時効挙動の結果を示した図表、第２図はその機械的性
質を要約して示す図表、第３図は製造例によるものの各
種試験結果を要約して示した図表である。
特許出願人 日本鋼管株式会社
発明者 高岡 遠離
同 石火 嘉−
同 稲積 透The drawings show the technical content of the present invention, with Fig. 1 being a diagram showing the results of short-term aging behavior of Niwa stainless steel at 400 to 600°C, and Fig. 2 showing its mechanical properties. Figure 3 is a diagram summarizing the results of various tests for manufacturing examples. Patent applicant: Nippon Kokan Co., Ltd. Inventor: Takaoka Tori Yoshi Ishibi Toru Inazumi
Claims (1)
ｎ：１．５ｗｔ％以下、Ｃｒ：２１〜２８ｗｔ％、Ｎｉ
：３〜８ｗｔ％、Ｍｏ：１〜４ｗｔ％、Ｎ：０．１〜０
．３ｗｔ％、Ｃｕ：２ｗｔ％以下、Ｗ：２ｗｔ％以下、
Ａｌ：０．０２ｗｔ％以下、Ｔｉ、Ｖ、Ｎｂ、Ｔａ：何
れも０．１ｗｔ％以下、Ｚｒ、Ｂ：何れも０．０１ｗｔ
％以下、 ｐ：０．０２ｗｔ％以下、Ｓ：０．００５ｗｔ％以下を
含有した鋼を１０００〜１１５０℃で溶体化熱処理後、
４５０〜５００℃で３０〜１２０分の時効熱処理するこ
とを特徴とするフェライト・オーステナイト２相ステン
レス鋼の製造方法。[Claims] C: 0.02wt% or less, Si: 1.0wt% or less, M
n: 1.5 wt% or less, Cr: 21 to 28 wt%, Ni
:3-8wt%, Mo:1-4wt%, N:0.1-0
．． 3wt%, Cu: 2wt% or less, W: 2wt% or less,
Al: 0.02wt% or less, Ti, V, Nb, Ta: all 0.1wt% or less, Zr, B: all 0.01wt
% or less, P: 0.02 wt% or less, S: 0.005 wt% or less, after solution heat treatment at 1000 to 1150°C,
A method for producing ferritic-austenitic duplex stainless steel, comprising aging heat treatment at 450-500°C for 30-120 minutes.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP27600384A JPS61157626A (en) | 1984-12-29 | 1984-12-29 | Manufacture of ferritic-austenitic two-phase stainless steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP27600384A JPS61157626A (en) | 1984-12-29 | 1984-12-29 | Manufacture of ferritic-austenitic two-phase stainless steel |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS61157626A true JPS61157626A (en) | 1986-07-17 |
Family
ID=17563417
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP27600384A Pending JPS61157626A (en) | 1984-12-29 | 1984-12-29 | Manufacture of ferritic-austenitic two-phase stainless steel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS61157626A (en) |
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5599408A (en) * | 1992-09-04 | 1997-02-04 | Mitsubishi Jukogyo Kabushiki Kaisha | Method of producing a structural member |
| US5716466A (en) * | 1993-12-20 | 1998-02-10 | Shinko Kosen Kogyo Kabushiki Kaisha | Stainless steel wire product |
| JP2012188727A (en) * | 2011-03-14 | 2012-10-04 | Nippon Steel & Sumikin Stainless Steel Corp | High-strength high-corrosion resistance stainless steel bolt excellent in stress corrosion crack resistance, and its manufacturing method |
| CN102770572A (en) * | 2010-02-18 | 2012-11-07 | 新日铁住金不锈钢株式会社 | Duplex stainless steel material for vacuum vessels, and process for manufacturing same |
| WO2014112445A1 (en) | 2013-01-15 | 2014-07-24 | 株式会社神戸製鋼所 | Duplex stainless steel material and duplex stainless steel pipe |
| JP2014141726A (en) * | 2013-01-25 | 2014-08-07 | Seiko Instruments Inc | Two-phase stainless steel, method of manufacturing the same, and diaphragm, pressure sensor, and diaphragm valve using two-phase stainless steel |
| JP2015078429A (en) * | 2013-09-11 | 2015-04-23 | 株式会社神戸製鋼所 | Duplex stainless steel material and duplex stainless steel tube |
| JP2015110828A (en) * | 2013-11-05 | 2015-06-18 | 株式会社神戸製鋼所 | Duplex stainless steel material and duplex stainless steel tube |
| JP2017002352A (en) * | 2015-06-09 | 2017-01-05 | 株式会社神戸製鋼所 | Duplex stainless steel material and duplex stainless steel pipe |
| WO2018043214A1 (en) | 2016-09-02 | 2018-03-08 | Ｊｆｅスチール株式会社 | Duplex stainless steel and method for manufacturing same |
| WO2018131412A1 (en) | 2017-01-10 | 2018-07-19 | Ｊｆｅスチール株式会社 | Duplex stainless steel and method for producing same |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5357117A (en) * | 1976-11-05 | 1978-05-24 | Daido Steel Co Ltd | Two phase stainless steel with low directionality of strength and toughness |
-
1984
- 1984-12-29 JP JP27600384A patent/JPS61157626A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5357117A (en) * | 1976-11-05 | 1978-05-24 | Daido Steel Co Ltd | Two phase stainless steel with low directionality of strength and toughness |
Cited By (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5599408A (en) * | 1992-09-04 | 1997-02-04 | Mitsubishi Jukogyo Kabushiki Kaisha | Method of producing a structural member |
| US5716466A (en) * | 1993-12-20 | 1998-02-10 | Shinko Kosen Kogyo Kabushiki Kaisha | Stainless steel wire product |
| CN102770572A (en) * | 2010-02-18 | 2012-11-07 | 新日铁住金不锈钢株式会社 | Duplex stainless steel material for vacuum vessels, and process for manufacturing same |
| JP2012188727A (en) * | 2011-03-14 | 2012-10-04 | Nippon Steel & Sumikin Stainless Steel Corp | High-strength high-corrosion resistance stainless steel bolt excellent in stress corrosion crack resistance, and its manufacturing method |
| CN104919072A (en) * | 2013-01-15 | 2015-09-16 | 株式会社神户制钢所 | Duplex stainless steel material and duplex stainless steel pipe |
| KR20150087430A (en) | 2013-01-15 | 2015-07-29 | 가부시키가이샤 고베 세이코쇼 | Duplex stainless steel material and duplex stainless steel pipe |
| WO2014112445A1 (en) | 2013-01-15 | 2014-07-24 | 株式会社神戸製鋼所 | Duplex stainless steel material and duplex stainless steel pipe |
| JP2014141726A (en) * | 2013-01-25 | 2014-08-07 | Seiko Instruments Inc | Two-phase stainless steel, method of manufacturing the same, and diaphragm, pressure sensor, and diaphragm valve using two-phase stainless steel |
| JP2015078429A (en) * | 2013-09-11 | 2015-04-23 | 株式会社神戸製鋼所 | Duplex stainless steel material and duplex stainless steel tube |
| JP2015110828A (en) * | 2013-11-05 | 2015-06-18 | 株式会社神戸製鋼所 | Duplex stainless steel material and duplex stainless steel tube |
| JP2017002352A (en) * | 2015-06-09 | 2017-01-05 | 株式会社神戸製鋼所 | Duplex stainless steel material and duplex stainless steel pipe |
| WO2018043214A1 (en) | 2016-09-02 | 2018-03-08 | Ｊｆｅスチール株式会社 | Duplex stainless steel and method for manufacturing same |
| US11566301B2 (en) | 2016-09-02 | 2023-01-31 | Jfe Steel Corporation | Dual-phase stainless steel, and method of production thereof |
| WO2018131412A1 (en) | 2017-01-10 | 2018-07-19 | Ｊｆｅスチール株式会社 | Duplex stainless steel and method for producing same |
| US11655526B2 (en) | 2017-01-10 | 2023-05-23 | Jfe Steel Corporation | Duplex stainless steel and method for producing same |
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