JPH02290920A - Production of high strength duplex stainless steel pipe - Google Patents
Production of high strength duplex stainless steel pipeInfo
- Publication number
- JPH02290920A JPH02290920A JP11092489A JP11092489A JPH02290920A JP H02290920 A JPH02290920 A JP H02290920A JP 11092489 A JP11092489 A JP 11092489A JP 11092489 A JP11092489 A JP 11092489A JP H02290920 A JPH02290920 A JP H02290920A
- Authority
- JP
- Japan
- Prior art keywords
- stainless steel
- strength
- duplex stainless
- steel pipe
- cold working
- 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.)
- Pending
Links
- 229910001039 duplex stainless steel Inorganic materials 0.000 title claims abstract description 21
- 238000004519 manufacturing process Methods 0.000 title claims description 4
- 238000005482 strain hardening Methods 0.000 claims abstract description 19
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 6
- 238000010438 heat treatment Methods 0.000 claims abstract description 4
- 238000000034 method Methods 0.000 abstract description 12
- 230000007797 corrosion Effects 0.000 abstract description 8
- 238000005260 corrosion Methods 0.000 abstract description 8
- 238000003483 aging Methods 0.000 abstract description 4
- 229910000831 Steel Inorganic materials 0.000 abstract description 3
- 238000007796 conventional method Methods 0.000 abstract description 3
- 239000010959 steel Substances 0.000 abstract description 3
- 230000002542 deteriorative effect Effects 0.000 abstract 1
- 230000032683 aging Effects 0.000 description 8
- 230000006866 deterioration Effects 0.000 description 6
- 238000012545 processing Methods 0.000 description 6
- 239000000243 solution Substances 0.000 description 6
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- 238000005728 strengthening Methods 0.000 description 3
- 229910052799 carbon Inorganic materials 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 239000003129 oil well Substances 0.000 description 2
- 238000005096 rolling process Methods 0.000 description 2
- 230000035882 stress Effects 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229910021578 Iron(III) chloride Inorganic materials 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 238000010622 cold drawing Methods 0.000 description 1
- 238000005097 cold rolling Methods 0.000 description 1
- 238000012733 comparative method Methods 0.000 description 1
- 238000012790 confirmation Methods 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 238000001192 hot extrusion Methods 0.000 description 1
- 238000009863 impact test Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- RBTARNINKXHZNM-UHFFFAOYSA-K iron trichloride Chemical compound Cl[Fe](Cl)Cl RBTARNINKXHZNM-UHFFFAOYSA-K 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 239000002436 steel type Substances 0.000 description 1
- 238000009864 tensile test Methods 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 239000002351 wastewater Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Heat Treatment Of Articles (AREA)
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は油井管として使用される高強度二相ステンレス
鋼管の製造法に関するものである。DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for manufacturing high-strength duplex stainless steel pipes used as oil country tubular goods.
（従来の技術）
油井用の二相ステンレス鋼管には、主に耐食性を考慮し
て高Ｎ系の成分系（例えばＪＩＳ Ｇ３４５９規格のＳ
ＵＳ３２９Ｊ２Ｌや八ＳＴＭ Ａ７８９ Ｓ３１８０３
など）が使用される。そして鋼管の製造方法は、熱間押
出法やマンネスマン圧延法などで製管された後、耐食性
確保のために高温で溶体化熱処理を施されるのが通例で
ある。しかし、この状態では二相ステンレス鋼の強度は
比較的低目で引張強さでたかだか８０ｋｇ ｆ ／ ｍ
ｊ、０．２％耐力でたかだか６０ｋｇｆ／一級である。(Prior art) Duplex stainless steel pipes for oil wells are made with high N-based components (for example, S
US329J2L and 8 STM A789 S31803
etc.) are used. In the manufacturing method of steel pipes, after the pipes are formed by hot extrusion method, Mannesmann rolling method, etc., they are usually subjected to solution heat treatment at high temperature to ensure corrosion resistance. However, in this state, the strength of duplex stainless steel is relatively low, with a tensile strength of only 80 kg f/m.
j, 0.2% proof stress is at most 60 kgf/first class.
ところが油井用二相ステンレス鋼管の場合、比較的高温
かつ高圧で使われるため０．２％耐力で７７〜１２０ｋ
ｇｆ／一程度の高強度が要求されている。However, in the case of duplex stainless steel pipes for oil wells, they are used at relatively high temperatures and pressures, so the 0.2% yield strength is 77 to 120 k.
A high strength of approximately gf/1 is required.
そこで、溶体化ままでの強度レヘルから所要の強度レベ
ルまで強化する手段として冷間引抜きや冷間圧延といっ
た冷間加工による加工硬化が利用されている。その強度
レベルの調゛整は加工量によって行なわれるが、加工硬
化による方法だけではかなり大きな冷間加工量を必要と
する場合が多く、設備的負荷の増大、加工中の割れの発
生、延性の劣化という問題点がある
（発明が解決しようとする課題）
本発明の目的は、前記の如き従来の二相ステンレス鋼の
強化法の問題点に鑑みて、新規で効果的な強化方法を提
供するにある。Therefore, work hardening by cold working such as cold drawing or cold rolling is used as a means to strengthen the strength from the strength level as it is in solution to the required strength level. The strength level is adjusted by the amount of processing, but work hardening alone often requires a considerably large amount of cold working, which increases equipment load, causes cracks during processing, and reduces ductility. There is a problem of deterioration (problem to be solved by the invention) The purpose of the present invention is to provide a new and effective strengthening method in view of the problems of the conventional strengthening method for duplex stainless steel as described above. It is in.
（課題を解決するための手段）
本発明者らは上記問題点を解消するために高Ｎ二相ステ
ンレス鋼管の上記以外の強化法について探索した結果、
歪時効硬化が効果的であることを知見した。すなわち、
熱間押出法などの各種製造法あるいはさらに溶体化処理
法などの熱処理を施して製造された高窒素二相ステンレ
ス鋼管（例えばＣ：０．０１ 〜０．１０％， Ｓｉ：
０．１〜１．０％， Ｍｎ：ｏ．３〜１．８％， Ｃ
ｒ：２ １〜２ ７％，Ｎｉ：３〜９％，Ｍｏ：２〜４
％，Ｎ： ０．１〜０．３％を含み、残部Ｆｅ及び不可
避的不純物からなる鋼管）を冷間加工によりある程度の
予歪を付加した後、２００℃前後の温度で人工時効する
ことにより約１０ｋｇｆ／一の強度上昇をもたらすこと
が可能であることを確かめた。(Means for Solving the Problems) In order to solve the above-mentioned problems, the present inventors have searched for methods of strengthening high-N duplex stainless steel pipes other than the above-mentioned ones.
We found that strain age hardening is effective. That is,
High nitrogen duplex stainless steel pipes (for example, C: 0.01 to 0.10%, Si:
0.1-1.0%, Mn:o. 3-1.8%, C
r: 2 1-2 7%, Ni: 3-9%, Mo: 2-4
%, N: 0.1 to 0.3%, with the balance consisting of Fe and unavoidable impurities). After adding a certain amount of pre-strain by cold working, artificial aging is performed at a temperature of around 200°C. It was confirmed that it was possible to bring about an increase in strength of about 10 kgf/1.
この現象の確認結果の例を第１図に示すが、この強度上
昇代は数％以上の歪量の領域では予歪量には無関係にほ
ぼ一定である。この強度上昇は高Ｎ二相ステンレス鋼管
の場合、溶体化処理で炭素と窒素とが十分に固溶してい
るので歪時効時に歪が固定される度合が大きいことに起
因し、他の鋼種よりは相当大きいものである。An example of the confirmation result of this phenomenon is shown in FIG. 1, and the strength increase is almost constant in the range of strain amount of several percent or more, regardless of the amount of pre-strain. This increase in strength is due to the fact that in the case of high-N duplex stainless steel pipes, carbon and nitrogen are sufficiently dissolved in solid solution during solution treatment, so that the degree of strain fixation during strain aging is greater than that of other steel types. is quite large.
歪時効硬化は一般には靭性や延性の劣化を伴なうので通
常は避けるべきとされている。ところが二相ステンレス
鋼管においては高靭性のγ相が約５０％共存しているこ
とにより歪時効硬化させても、第２図で示すように、靭
性の変化は微量である。すなわち、本発明はこのような
高Ｎ系二相ステンレス鋼管の特性を効果的に利用するも
のである。Strain age hardening is generally accompanied by deterioration of toughness and ductility and is therefore generally considered to be avoided. However, in duplex stainless steel pipes, approximately 50% of the high-toughness γ phase coexists, so even when strain-age hardened, the change in toughness is minimal, as shown in FIG. That is, the present invention effectively utilizes the characteristics of such a high-N duplex stainless steel pipe.
すなわち、本発明は０．１〜０．３％のＮを含有する二
相ステンレス綱管を、断面減少率で５〜５０％の冷間加
工を付与した後、１００〜３５０℃の温度域で３０分間
以上加熱することを要旨とするものであり、本発明によ
れば、時効硬化現象により耐食性や靭性を損なうことな
く強度を向上せしめることができる。That is, the present invention cold-works a duplex stainless steel tube containing 0.1-0.3% N at a reduction rate of 5-50% in a temperature range of 100-350°C. The gist is to heat for 30 minutes or more, and according to the present invention, strength can be improved without impairing corrosion resistance or toughness due to age hardening phenomenon.
以下に本発明の構成要件の限定理由について詳細に述べ
る。The reasons for limiting the constituent elements of the present invention will be described in detail below.
１） Ｎ量：０．１％未満では歪時効による強度上昇
が小さく、また０．３％超では溶製時の固溶限を超える
ためこれを超えて添加できない。したがって、Ｎの含有
量を０． １〜０．３％にした，２） 冷間加工量：５
％未満の小さい加工量では歪時効後に得られる強度値が
低く、本発明の目標とする７７ｋｇ／一以上の０．２％
耐力が得られない。1) N content: If it is less than 0.1%, the increase in strength due to strain aging will be small, and if it exceeds 0.3%, it will exceed the solid solubility limit during melting, so it cannot be added in excess of this. Therefore, the N content is reduced to 0. 1 to 0.3%, 2) Cold working amount: 5
%, the strength obtained after strain aging is low, and the target of the present invention is 0.2% of 77 kg/1 or more.
Cannot obtain durability.
一方５０％超に加工量を増加させても強度はほぼ飽和す
ること、および材料の加工限界に近づき場合によって加
工割れを起こす傾向があることから５０％を上限値とす
る。On the other hand, even if the amount of processing is increased to more than 50%, the strength is almost saturated, and the material tends to approach the processing limit, causing processing cracks in some cases, so 50% is set as the upper limit.
３）時効条件：温度が１００℃未満、加熱時間が３０分
未満では時効が不十分で得られる強度が低い。一方、３
５０℃超の時効では強度上昇の点では十分であるが、い
わゆる４ １ ５ ”Ｃ脆性現象で炭窒化物の析出が起
こり耐食性と切欠靭性がゑ、激に劣化する。したがって
、耐食性、靭性を劣化させずに高い強度上昇が確保でき
る条件として１００〜３５０℃の温度範囲で３０分以上
加熱（保定）する必要がある。3) Aging conditions: If the temperature is less than 100°C and the heating time is less than 30 minutes, aging will be insufficient and the strength obtained will be low. On the other hand, 3
Aging at temperatures exceeding 50°C is sufficient in terms of increasing strength, but precipitation of carbonitrides occurs due to the so-called 4 15 "C embrittlement phenomenon, resulting in severe deterioration of corrosion resistance and notch toughness. As a condition for ensuring a high strength increase without deterioration, it is necessary to heat (retain) at a temperature range of 100 to 350°C for 30 minutes or more.
次に本発明の実施例について説明する。Next, examples of the present invention will be described.
（実施例）
第１表に示す二相ステンレス鋼を使用し、マンネスマン
圧延法によって１５０φ×１１ｔサイズの継目無綱管を
製造した。それらのパイプを１０５０’Ｃ Ｘ ２ ０
分→水冷の条件で溶体化処理した後、第２表に示す条件
で冷間加工および時効処理を施した。特性調査としては
引張試験による０． ２％耐力の測定、２ｍｍＶノッチ
シャルビー試験による−５ｏ℃での吸収エネルギー（試
験片は５ｍＩＩ１サブサイズ）の測定、塩化第二鉄溶液
中での耐孔食性の評価（ＡＳＴＭ Ｇ４８通り）とを実
施した。(Example) Using the duplex stainless steel shown in Table 1, a seamless steel pipe with a size of 150φ×11t was manufactured by the Mannesmann rolling method. Those pipes are 1050'C x 20
After solution treatment under the condition of water cooling, cold working and aging treatment were performed under the conditions shown in Table 2. Characteristics were investigated using a tensile test. Measurement of 2% proof stress, measurement of absorbed energy at -5oC by 2mmV notch Charby test (test piece is 5mII1 subsize), evaluation of pitting corrosion resistance in ferric chloride solution (ASTM G48 standard) carried out.
試験結果は、第２表中に示す。表中の符号■〜■は本発
明の条件を満たすものであり、■〜［相］は比較のため
の本発明の範囲外の条件のものである。The test results are shown in Table 2. In the table, the numbers ■ to ■ satisfy the conditions of the present invention, and the numbers ■ to [phase] correspond to conditions outside the scope of the present invention for comparison.
本発明の条件を満たすものの、諸特性として目標とする
７７ｋｇ／一以上の０． ２％耐力が得られていること
、靭性および耐孔食性の劣化が起こっていないことが確
認された。一方比較法のものは三つの条件のうち何れか
の点で問題のある結果となっている。Although the conditions of the present invention are met, the target 77 kg/1 or more 0. It was confirmed that 2% yield strength was obtained and that no deterioration of toughness and pitting corrosion resistance occurred. On the other hand, the comparative method yields problematic results in one of the three conditions.
（発明の効果）
本発明によれば、冷間加工のみによって強度向上をはか
っていた従来法に比べて約１０ｋｇ／一程度強度が上昇
し同一強度を得るための所要冷間加工量を低減できるの
で冷間加工工程への負荷を軽減できる。一方別の重要特
性である耐食性や靭性の強度上昇による劣化は従来法と
同様に本発明法でもほとんど認められない。(Effects of the Invention) According to the present invention, the strength can be increased by about 10 kg/1 compared to the conventional method in which strength was improved only by cold working, and the amount of cold working required to obtain the same strength can be reduced. Therefore, the load on the cold working process can be reduced. On the other hand, deterioration of corrosion resistance and toughness, which are other important properties, due to increased strength is hardly observed in the method of the present invention as in the conventional method.
以上の如く、本発明は高Ｎ系二相ステンレス鋼で耐食性
や靭性を損なうことなく冷間加工工程を簡略化しつつ高
強度を容易に得られる効果的な技術である。As described above, the present invention is an effective technique for easily obtaining high strength in high N duplex stainless steel while simplifying the cold working process without impairing corrosion resistance or toughness.
第１図は強度におよぼす冷間加工量の影響を示す図、第
２図は溶体化まま、冷間加工まま、冷間加工十人工時効
の三条件について求めた２ ｍｍ Ｖノッチシャルビー
衝撃試験での遷移曲線を示す図である。
第１図
〉廃潤加工ｔ（〃）
第２図
試験渫崖（゛Ｃ）Figure 1 is a diagram showing the effect of the amount of cold working on strength, and Figure 2 is a 2 mm V-notch Charby impact test determined under three conditions: as-solution treated, as-cold-worked, and cold-worked and artificially aged. It is a figure which shows the transition curve in . Figure 1〉Waste water processing t (〃) Figure 2 Test cliff (゛C)
Claims (1)
、断面減少率で５〜５０％の冷間加工を付与した後、１
００〜３５０℃の温度で３０分間以上加熱することを特
徴とする高強度二相ステンレス鋼管の製造方法。A duplex stainless steel pipe containing 0.1 to 0.3% N was subjected to cold working with a reduction in area of 5 to 50%, and then
A method for producing a high-strength duplex stainless steel pipe, which comprises heating at a temperature of 00 to 350°C for 30 minutes or more.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11092489A JPH02290920A (en) | 1989-04-28 | 1989-04-28 | Production of high strength duplex stainless steel pipe |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11092489A JPH02290920A (en) | 1989-04-28 | 1989-04-28 | Production of high strength duplex stainless steel pipe |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH02290920A true JPH02290920A (en) | 1990-11-30 |
Family
ID=14548070
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP11092489A Pending JPH02290920A (en) | 1989-04-28 | 1989-04-28 | Production of high strength duplex stainless steel pipe |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH02290920A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1998000626A1 (en) * | 1996-07-01 | 1998-01-08 | Shell Internationale Research Maatschappij B.V. | Method for expanding a steel tubing and well with such a tubing |
| WO2009014001A1 (en) | 2007-07-20 | 2009-01-29 | Sumitomo Metal Industries, Ltd. | Process for production of duplex stainless steel tubes |
| JP4462454B1 (en) * | 2009-01-19 | 2010-05-12 | 住友金属工業株式会社 | Manufacturing method of duplex stainless steel pipe |
| WO2010082395A1 (en) | 2009-01-19 | 2010-07-22 | 住友金属工業株式会社 | Process for production of duplex stainless steel pipe |
-
1989
- 1989-04-28 JP JP11092489A patent/JPH02290920A/en active Pending
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1998000626A1 (en) * | 1996-07-01 | 1998-01-08 | Shell Internationale Research Maatschappij B.V. | Method for expanding a steel tubing and well with such a tubing |
| WO2009014001A1 (en) | 2007-07-20 | 2009-01-29 | Sumitomo Metal Industries, Ltd. | Process for production of duplex stainless steel tubes |
| JP2009046759A (en) * | 2007-07-20 | 2009-03-05 | Sumitomo Metal Ind Ltd | Process for production of duplex stainless steel tubes |
| US8333851B2 (en) | 2007-07-20 | 2012-12-18 | Sumitomo Metal Industries, Ltd. | Method for producing two-phase stainless steel pipe |
| JP4462454B1 (en) * | 2009-01-19 | 2010-05-12 | 住友金属工業株式会社 | Manufacturing method of duplex stainless steel pipe |
| WO2010082395A1 (en) | 2009-01-19 | 2010-07-22 | 住友金属工業株式会社 | Process for production of duplex stainless steel pipe |
| CN102282273A (en) * | 2009-01-19 | 2011-12-14 | 住友金属工业株式会社 | Process for production of duplex stainless steel pipe |
| US8293037B2 (en) | 2009-01-19 | 2012-10-23 | Sumitomo Metal Industries, Ltd. | Method for producing duplex stainless steel pipe |
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