JPH0375336A - Martensitic stainless steel having excellent corrosion resistance and its manufacture - Google Patents
Martensitic stainless steel having excellent corrosion resistance and its manufactureInfo
- Publication number
- JPH0375336A JPH0375336A JP21104789A JP21104789A JPH0375336A JP H0375336 A JPH0375336 A JP H0375336A JP 21104789 A JP21104789 A JP 21104789A JP 21104789 A JP21104789 A JP 21104789A JP H0375336 A JPH0375336 A JP H0375336A
- Authority
- JP
- Japan
- Prior art keywords
- less
- stainless steel
- corrosion resistance
- martensitic stainless
- excellent corrosion
- 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
- 238000005260 corrosion Methods 0.000 title claims abstract description 85
- 230000007797 corrosion Effects 0.000 title claims abstract description 85
- 229910001105 martensitic stainless steel Inorganic materials 0.000 title claims abstract description 28
- 238000004519 manufacturing process Methods 0.000 title claims description 7
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 32
- 239000010959 steel Substances 0.000 claims abstract description 32
- 238000001816 cooling Methods 0.000 claims abstract description 25
- 238000005496 tempering Methods 0.000 claims abstract description 10
- 239000012535 impurity Substances 0.000 claims abstract description 7
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 5
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 5
- 229910052748 manganese Inorganic materials 0.000 claims abstract 3
- 229910052759 nickel Inorganic materials 0.000 claims abstract 3
- 229910052761 rare earth metal Inorganic materials 0.000 claims description 8
- 229910052715 tantalum Inorganic materials 0.000 claims description 6
- 229910052726 zirconium Inorganic materials 0.000 claims description 5
- 229910052758 niobium Inorganic materials 0.000 claims description 4
- 229910052719 titanium Inorganic materials 0.000 claims description 4
- 229910052735 hafnium Inorganic materials 0.000 claims description 3
- 229910052742 iron Inorganic materials 0.000 claims description 2
- 229910052750 molybdenum Inorganic materials 0.000 claims description 2
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 abstract description 40
- 238000005336 cracking Methods 0.000 abstract description 32
- RWSOTUBLDIXVET-UHFFFAOYSA-N Dihydrogen sulfide Chemical compound S RWSOTUBLDIXVET-UHFFFAOYSA-N 0.000 abstract description 21
- 229910000037 hydrogen sulfide Inorganic materials 0.000 abstract description 21
- 239000001569 carbon dioxide Substances 0.000 abstract description 20
- 229910002092 carbon dioxide Inorganic materials 0.000 abstract description 20
- 229910000734 martensite Inorganic materials 0.000 abstract description 8
- 229910001220 stainless steel Inorganic materials 0.000 abstract description 7
- 239000010935 stainless steel Substances 0.000 abstract description 6
- 229910052757 nitrogen Inorganic materials 0.000 abstract description 3
- 230000000694 effects Effects 0.000 description 14
- 239000000463 material Substances 0.000 description 7
- 229920006395 saturated elastomer Polymers 0.000 description 7
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 6
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 4
- 239000003112 inhibitor Substances 0.000 description 4
- 229910052720 vanadium Inorganic materials 0.000 description 4
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 3
- 239000003345 natural gas Substances 0.000 description 3
- 239000007864 aqueous solution Substances 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 238000005098 hot rolling Methods 0.000 description 2
- 239000011780 sodium chloride Substances 0.000 description 2
- 229910000851 Alloy steel Inorganic materials 0.000 description 1
- 229910000975 Carbon steel Inorganic materials 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 229910001566 austenite Inorganic materials 0.000 description 1
- 239000010962 carbon steel Substances 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000005553 drilling Methods 0.000 description 1
- -1 for example Inorganic materials 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000001192 hot extrusion Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- 239000003129 oil well Substances 0.000 description 1
- 239000003209 petroleum derivative Substances 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000007655 standard test method Methods 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は耐食性の優れたマルテンサイト系ステンレス鋼
およびその製造方法に係り、さらに詳しくは例えば石油
・天然ガスの掘削、輸送及び貯蔵において湿潤炭酸ガス
や湿潤硫化水素を含む環境中で高い腐食抵抗および割れ
抵抗を有する高強度鋼とその製造方法に関する。Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a martensitic stainless steel with excellent corrosion resistance and a method for producing the same. This invention relates to a high-strength steel that has high corrosion resistance and cracking resistance in environments containing gas and wet hydrogen sulfide, and a method for producing the same.
（従来の技術）
近年生産される石油・天然ガス中には、湿潤な炭酸ガス
を多く含有する場合が増加している。こうした環境中で
炭素鋼や低合金鋼は著しく腐食することがよく知られて
いる。このため、掘削に使用される油井管や輸送に使用
されるラインパイプなどの防食対策として、腐食抑制剤
の添加が従来より行なわれてきた。しかし、腐食抑制剤
は高温ではその効果が失われる場合が多いことに加えて
、海洋油井や海底パイプラインでは腐食抑制剤の添加・
回収処理に要する費用は膨大なものとなり、適用できな
い場合が多い。従って、腐食抑制剤を添加する必要のな
い耐食材料に対するニーズが最近とみに高まっている。(Prior Art) Oil and natural gas produced in recent years increasingly contain a large amount of wet carbon dioxide. It is well known that carbon steel and low alloy steel corrode significantly in such environments. For this reason, corrosion inhibitors have traditionally been added to prevent corrosion of oil country tubular goods used for drilling, line pipes used for transportation, and the like. However, corrosion inhibitors often lose their effectiveness at high temperatures, and in offshore oil wells and submarine pipelines, corrosion inhibitors are
The costs required for recovery processing are enormous and are often not applicable. Therefore, the need for corrosion-resistant materials that do not require the addition of corrosion inhibitors has recently increased.
炭酸ガスを多く含む石油・天然ガ００の耐食材料として
は、耐食性の良好なステンレス鋼の適用かまず検討され
、例えばり、Ｊ、クライン、コロ−ジョン ′８４．ペ
ーパーナンバー２１１にあるように、高強度で比較的コ
ストの安い鋼としてＡｌ５Ｉ４１０あるいは４２０とい
った、１２〜１３％のＣｒを含有するマルテンサイト系
ステンレス鋼が広く使用され始めている。しかしながら
、これらの鋼は湿潤炭酸ガス環境ではあっても高温、例
えば１２０℃以上の環境やＣｔ−イオン濃度の高い環境
では耐食性が十分ではなくなり、腐食速度が大きいとい
う難点を有する。さらにこれらの鋼は、石油・天然ガス
中に硫化水素が含まれている場合には著しく耐食性が劣
化し、全面腐食や局部腐食、さらには応力腐食割れを生
ずるという難点を有している。このため上記のマルテン
サイト系ステンレス鋼の使用は、例えばＨ２Ｓ分圧が０
．００１気圧といった極微量のＵＺＳを含むか、あるい
は全＜ Ｈ２Ｓを含まない場合に限られてきた。As a corrosion-resistant material for petroleum and natural gas containing a large amount of carbon dioxide, the application of stainless steel, which has good corrosion resistance, was first considered, and for example, J. Klein, Corrosion '84. As described in Paper No. 211, martensitic stainless steel containing 12 to 13% Cr, such as Al5I410 or Al5I420, has begun to be widely used as a high-strength, relatively inexpensive steel. However, these steels have the disadvantage that even in a humid carbon dioxide environment, their corrosion resistance is insufficient and their corrosion rate is high at high temperatures, for example, 120° C. or higher, or environments with a high Ct-ion concentration. Furthermore, these steels have the disadvantage that when hydrogen sulfide is contained in oil or natural gas, their corrosion resistance is significantly deteriorated, causing general corrosion, localized corrosion, and even stress corrosion cracking. Therefore, when using the above martensitic stainless steel, for example, the H2S partial pressure is 0.
．． It has been limited to cases where it contains a very small amount of UZS such as 0.001 atm, or when it does not contain total H2S.
これに対し、硫化水素による割れに対する抵抗を増した
マルテンサイト系ステンレス鋼として、例えば特開昭６
０−１７４８５９号公報、特開昭６２−５４０６３号公
報にみられる鋼が提案されている。しかし、これらの鋼
もＣＯ□環境での耐食性が必ずしも十分という訳ではな
かった。On the other hand, as martensitic stainless steel with increased resistance to cracking due to hydrogen sulfide, for example,
Steels disclosed in Japanese Patent Application Laid-open No. 0-174859 and Japanese Patent Application Laid-Open No. 62-54063 have been proposed. However, these steels did not necessarily have sufficient corrosion resistance in a CO□ environment.
（発明が解決しようとする課題）
本発明はこうした現状に鑑み、高温や高ＣＩ−イオン濃
度の炭酸ガス環境でも十分な耐食性を有し、硫化水素を
含む場合においても高い割れ抵抗を有するマルテンサイ
ト系ステンレス鋼とその製造方法を提供することを目的
としている。(Problems to be Solved by the Invention) In view of the current situation, the present invention has been developed using martensite, which has sufficient corrosion resistance even in a carbon dioxide environment with high temperature and high CI-ion concentration, and has high cracking resistance even when containing hydrogen sulfide. The purpose is to provide stainless steels and their manufacturing methods.
（課題を解決するための手段）
本発明者らは、上記の目的を達成すべくマルテンサイト
系ステンレス鋼の成分を種々検討してきた結果、ついに
以下の知見を見出すに至った。(Means for Solving the Problem) The present inventors have studied various components of martensitic stainless steel in order to achieve the above object, and as a result, they have finally found the following knowledge.
まず、Ｃｒを１５％を超えて鋼に添加すると湿潤炭酸ガ
ス環境中における腐食速度が著しく小さくなり、かかる
鋼にＮｉを添加すると腐食速度は一段と小さくなること
を見出した。そしてこのＮｉの添加効果は、添加量を１
％以上とすると顕著であることを見出した。また、Ｎｉ
を１％以上添加した場合において、Ｃ量を０．０３％未
満に低減すると湿濶炭酸ガス環境中における耐食性がさ
らに改善され、２００ ’Ｃ以上にまで使用が可能にな
ることが分かった。一方、Ｎｉを１％以上添加しＣを０
．０３％未満に低減させた綱にＮを０．０３％以上含有
させると一段と高強度が得られることがわかった。First, we found that when more than 15% of Cr was added to steel, the corrosion rate in a wet carbon dioxide environment was significantly reduced, and when Ni was added to such steel, the corrosion rate was further reduced. The effect of adding Ni is that when the added amount is 1
% or more, it was found that it was remarkable. Also, Ni
It has been found that when 1% or more of C is added, reducing the amount of C to less than 0.03% further improves corrosion resistance in a humid carbon dioxide environment, making it possible to use the steel at temperatures above 200'C. On the other hand, when more than 1% of Ni is added, C is reduced to 0.
．． It has been found that even higher strength can be obtained by adding 0.03% or more of N to a steel whose strength has been reduced to less than 0.03%.
このときかかる成分を有する鋼は硫化水素を含む環境に
おいても高い割れ抵抗を有するという新知見も得られた
。At this time, new findings were also obtained that steel with such components has high cracking resistance even in environments containing hydrogen sulfide.
さらに本発明者らは検討をすすめ、Ｎｉを１％以上添加
し、Ｃを０．０３％未満に低減し、Ｎを０．０３％以上
添加した鋼中のＰを０．０２５％以下に低減し、Ｓをｏ
、ｏｔｏ％以下に低減するか、０を０．００４％以下に
低減するか、のいずれかを適用すると硫化水素を含む環
境における割れ抵抗が一段と改善されることを明らかに
した。一方、これらの綱にＣｕ、 Ｍｏ、 Ｗを添加す
れば高温あるいは高ＣＩ−イオン濃度の湿潤炭酸ガス環
境での腐食速度を一段と減少できることも見出した。Furthermore, the present inventors proceeded with studies and found that Ni was added at least 1%, C was reduced to less than 0.03%, and P in steels to which N was added at least 0.03% was reduced to 0.025% or less. and S o
, oto% or less, or reducing 0 to 0.004% or less, the cracking resistance in an environment containing hydrogen sulfide is further improved. On the other hand, we have also found that by adding Cu, Mo, and W to these steels, it is possible to further reduce the corrosion rate in a humid carbon dioxide environment at high temperatures or in a high CI-ion concentration.
本発明は上記の知見に基づいてなされたものであり、
第１発明の要旨とするところは、重量％で、Ｃｒ１５％
超１８％以下、Ｎｔｌ〜５％、Ｓｉ１％以下。The present invention has been made based on the above knowledge, and the gist of the first invention is that Cr15% by weight
Super 18% or less, Ntl ~ 5%, Si 1% or less.
Ｍｎ２％以下、 ＡＺｏ、００５〜０．２％、ＮＯ，０
３〜０、１５％を含有し、Ｃを０．０３％未満に低減し
、残部Ｆｅおよび不可避不純物からなることを特徴とす
る耐食性の優れたマルテンサイト系ステンレス鋼にあり
、
第２発明の要旨とするところは、第１発明の綱において
、不可避不純物のうち、重量％で、Ｐを０、０２５％以
下、Ｓを０．０１０％以下に低減したことを特徴とする
耐食性の優れたマルテンサイト系ステンレス鋼にあり、
第３発明の要旨とするところは、第１発明あるいは第２
発明の鋼において不可避不純物のうち、重量％で、Ｏを
０．００４％以下に低減したことを特徴とする耐食性の
優れたマルテンサイト系ステンレス鋼にあり、
第４発明の要旨とするところは、第１発明、第２発明あ
るいは第３発明の基調において、重量％で、Ｃｕ１％以
下、Ｍｏ２％以下、Ｗ４％以下のうち１種または２種以
上を含有することを特徴とする耐食性の優れたマルテン
サイト系ステンレス鋼にあり、
第５発明の要旨とするところは、第１発明、第２発明、
第３発明あるいは第４発明の基調において、重量％で、
Ｔｉ０．２％以下、ＺｒＯ，２％以下、 Ｎｂ０１５％
以下、Ｖｏ、５％以下、Ｔａ０．２％以下、 ＩｆＯ８
２％以下のうち１種または２種以上を含有することを特
徴とする耐食性の優れたマルテンサイト系ステンレス鋼
にあり、
第６発明の要旨とするところは、第１発明、第２発明、
第３発明、第４発明あるいは第５発明の基調において、
重量％で、Ｃａ０．００８％以下、希土類元素０．０２
％以下のうち１種または２種を含有することを特徴とす
る耐食性の優れたマルテンサイト系ステンレス鋼にあり
、
第７発明の要旨とするところは、第１発明、第２発明、
第３発明、第４発明、第５発明あるいは第６発明の基調
において、９００〜１１００’Ｃでオーステナイト化し
た後、空冷以上の冷却速度で冷却し、次いで５６０″Ｃ
以上Ａ ｃ １温度以下の温度で焼戻し処理を施した後
、空冷以上の冷却速度で冷却することを特徴とする耐食
性の優れたマルテンサイト系ステンレス鋼の製造方法に
ある。Mn 2% or less, AZo, 005~0.2%, NO, 0
A martensitic stainless steel with excellent corrosion resistance, characterized by containing 3 to 0.15%, C reduced to less than 0.03%, and the remainder consisting of Fe and unavoidable impurities. In the first aspect of the invention, martensite with excellent corrosion resistance is characterized by reducing P to 0.025% or less and S to 0.010% or less among unavoidable impurities by weight. system stainless steel, and the gist of the third invention is that the first invention or the second invention
The fourth aspect of the invention resides in a martensitic stainless steel with excellent corrosion resistance, which is characterized by reducing O to 0.004% by weight or less among the inevitable impurities in the steel of the invention. In the basic tone of the first invention, second invention, or third invention, the material has excellent corrosion resistance characterized by containing one or more of Cu1% or less, Mo2% or less, and W4% or less in weight%. Regarding martensitic stainless steel, the gist of the fifth invention is that the first invention, the second invention,
In the keynote of the third invention or the fourth invention, in weight%,
Ti 0.2% or less, ZrO, 2% or less, Nb015%
Below, Vo, 5% or less, Ta 0.2% or less, IfO8
The sixth invention provides a martensitic stainless steel with excellent corrosion resistance characterized by containing one or more of 2% or less of the following: the first invention, the second invention,
In the keynote of the third invention, fourth invention, or fifth invention,
In weight%, Ca 0.008% or less, rare earth elements 0.02
% or less, the martensitic stainless steel has excellent corrosion resistance, and the gist of the seventh invention is the first invention, the second invention,
In the keynote of the third, fourth, fifth, or sixth invention, after austenitizing at 900 to 1100'C, cooling at a cooling rate higher than air cooling, and then cooling to 560'C
The present invention provides a method for producing martensitic stainless steel having excellent corrosion resistance, which comprises performing a tempering treatment at a temperature of A c 1 or lower and then cooling at a cooling rate higher than or equal to air cooling.
（作 用）
以下に本発明で成分および熱処理条件を限定した理由を
述べる。(Function) The reasons for limiting the components and heat treatment conditions in the present invention will be described below.
Ｃ：Ｃは多量に存在すると湿潤炭酸ガス環境における耐
食性を低下させ、硫化水素の存在する環境における応力
腐食割れ抵抗を減少させる。従って、Ｃを低減するとこ
れら特性の改善に効果があるが、Ｃｔを０．０３％未満
とすれば特にその効果が著しく、０．０３％以上存在す
る場合には耐食性を低下させることから、Ｃｔは０．０
３％未満に限定する。C: When present in a large amount, C reduces corrosion resistance in a wet carbon dioxide environment and reduces stress corrosion cracking resistance in an environment where hydrogen sulfide is present. Therefore, reducing Ct is effective in improving these properties, but the effect is particularly significant when Ct is less than 0.03%, and when Ct is present at 0.03% or more, corrosion resistance is reduced. is 0.0
Limited to less than 3%.
Ｓｔ ： Ｓｔは脱酸のために必要な元素であるが、１
％を超えて添加すると耐食性を著しく低下させることか
ら、上限含有量は１％とすべきである。St: St is an element necessary for deoxidation, but 1
If added in excess of 1%, the corrosion resistance will be significantly reduced, so the upper limit content should be 1%.
Ｍｎ ： Ｍｎは脱酸および強度確保のために有効な元
素であるが、２％を超えて添加するとその効果は飽和す
るので、上限含有量は２％とする。Mn: Mn is an effective element for deoxidizing and ensuring strength, but its effect becomes saturated when added in excess of 2%, so the upper limit content is set to 2%.
Ｃｒ ： Ｃｒはマルテンサイト系ステンレス鋼を構成
する最も基本的かつ必須の元素であって耐食性を付与す
るために必要な元素であるが、含有量が１５％以下では
耐食性が十分ではなく、一方１８％を超えて添加すると
他の合金元素をいかに調整しても焼き入れ後にマルテン
サイト組織を得ることが困難となって強度確保が困難に
なるので上限含有量は１８％とすべきである。Cr: Cr is the most basic and essential element constituting martensitic stainless steel, and is necessary for imparting corrosion resistance. However, if the content is less than 15%, corrosion resistance is insufficient; If it is added in an amount exceeding 18%, it will be difficult to obtain a martensitic structure after quenching and it will be difficult to ensure strength, no matter how the other alloying elements are adjusted. Therefore, the upper limit content should be 18%.
Ｎｉ ： Ｎｉは湿潤炭酸ガス環境におけるマルテンサ
イト系ステンレス鋼の腐食速度を著しく減少させ、Ｃお
よびＮの含有量を調整することによって硫化水素を含む
環境における割れ感受性を顕著に低下させる極めて有用
な元素であるが、含有量が１％未満ではこれらの効果が
不十分であり、５％を超えて添加してもその効果は飽和
するので、１〜５％の範囲に限定する。Ni: Ni is an extremely useful element that significantly reduces the corrosion rate of martensitic stainless steel in a humid carbon dioxide environment and significantly reduces the cracking susceptibility in an environment containing hydrogen sulfide by adjusting the C and N content. However, if the content is less than 1%, these effects will be insufficient, and if it exceeds 5%, the effects will be saturated, so it is limited to a range of 1 to 5%.
Ｎ：ＡＩは脱酸のために必要な元素であって含有量がＯ
，ＯＯ５％未満ではその効果が十分ではなく、０．２％
を超えて添加すると粗大な酸化物系介在物が鋼中に残留
して硫化水素中での割れ抵抗を低下させるので、含有量
範囲はｏ、 ｏ ｏ ｓ〜０．２％とする。N: AI is an element necessary for deoxidation, and the content is O.
, the effect is not sufficient when OO is less than 5%, and 0.2%
If it is added in excess of 0.2%, coarse oxide inclusions will remain in the steel and reduce the cracking resistance in hydrogen sulfide, so the content range is set to 0.2% to 0.2%.
Ｎ：ＮはＣを低減したマルテンサイト系ステンレス鋼の
強度を上昇させる元素として有効であるが、０．０３％
未満ではその効果が充分ではなく、０．１５％を超える
とＣｒ窒化物を生成して耐食性を低下させ、また、割れ
抵抗をも低下させるので、含有量範囲は０．０３〜０．
１５％とする。N: N is effective as an element for increasing the strength of martensitic stainless steel with reduced C content, but at 0.03%
If it is less than 0.15%, the effect will not be sufficient, and if it exceeds 0.15%, Cr nitrides will be formed, reducing corrosion resistance and cracking resistance, so the content range is from 0.03 to 0.
It shall be 15%.
以上が本発明における基本的成分であるが、本発明にお
いては必要に応じてさらに以下の元素を添加して特性を
一段と向上させることができる。The above are the basic components in the present invention, but in the present invention, the following elements can be further added as necessary to further improve the characteristics.
ＦＤＰは応力腐食割れ感受性を増加させる元素であるの
で少ないほうが好ましいが、あまりに少ないレベルにま
で低減させることは、いたずらにコストを上昇させるの
みで特性の改善効果は飽和するものであるから、本発明
の目的とする耐食性。Since FDP is an element that increases stress corrosion cracking susceptibility, it is preferable to reduce it to a low level, but reducing it to too low a level will only unnecessarily increase costs and the effect of improving properties will be saturated. The target corrosion resistance.
耐応力腐食割れ性を確保するのに必要十分なほど少ない
含有量として０．０２５％以下に低減すると耐応力腐食
割れ性が一段と改善される。When the content is reduced to 0.025% or less, which is sufficiently small to ensure stress corrosion cracking resistance, stress corrosion cracking resistance is further improved.
ＳＯ３はＰと同様に応力腐食割れ感受性を増加させる元
素であるので少ないほうが好ましいが、あまりに少ない
レベルにまで低減させることはいたずらにコストを上昇
させるのみで特性の改善効果は飽和するものであるから
、本発明の目的とする耐食性、耐応力腐食割れ性を確保
するのに必要十分なほど少ない含有量として０．０１０
％以下に低減すると耐応力腐食割れ性が一段と改善され
る。Like P, SO3 is an element that increases stress corrosion cracking susceptibility, so it is better to have less SO3, but reducing it to too low a level will only unnecessarily increase costs and the effect of improving properties will be saturated. , the content is 0.010 as low as necessary and sufficient to ensure the corrosion resistance and stress corrosion cracking resistance targeted by the present invention.
% or less, stress corrosion cracking resistance is further improved.
Ｏ：Ｏは多量に存在すると粗大な酸化物系非金属介在物
クラスターを生成して応力腐食割れ感受性を増加させる
ので少ないほうが好ましいが、あまりに少ないレベルに
まで低減させることはいたずらにコストを上昇させるの
みで特性の改善効果は飽和するものであるから、本発明
の目的とする耐食性、耐応力腐食割れ性を一段と改善す
るのに必要充分なほど少ない含有量として０．００４％
以下に低減すると耐応力腐食割れ性が一段と改善される
。O: If O is present in a large amount, it will generate coarse oxide-based nonmetallic inclusion clusters and increase stress corrosion cracking susceptibility, so it is preferable to have a small amount, but reducing it to too low a level will unnecessarily increase costs. Since the property improvement effect is saturated with only 0.004%, the content is as low as necessary and sufficient to further improve the corrosion resistance and stress corrosion cracking resistance that are the objectives of the present invention.
When the stress corrosion cracking resistance is reduced to below, the stress corrosion cracking resistance is further improved.
Ｃｕ ： Ｃｕは１％以上のＮｉと共存して湿潤炭酸ガ
ス環境の耐食性をさらに改善するのに効果があるが、１
％を超えて添加してもその効果は飽和するので上限含有
量は１％とする。Cu: Cu coexists with 1% or more of Ni and is effective in further improving corrosion resistance in a wet carbon dioxide environment.
Even if it is added in an amount exceeding 1%, the effect will be saturated, so the upper limit content is set at 1%.
Ｍｏ ： Ｍｏは１％以上のＮｉと共存して湿潤炭酸ガ
ス環境の耐食性を改善するのに効果があるが、２％を超
えて添加してもその効果は飽和するばかりか、靭性なと
他の特性を低下させるようになるので上限含有量は２％
とする。Mo: Mo coexists with 1% or more of Ni and is effective in improving corrosion resistance in a wet carbon dioxide environment, but if it is added in excess of 2%, the effect not only becomes saturated, but also deteriorates toughness and other properties. The upper limit content is 2% because it reduces the properties of
shall be.
ＷＯＷも１％以上のＮｉと共存して湿潤炭酸ガス環境の
耐食性を改善するのに効果があるが、４％を超えて添加
してもその効果は飽和するばかりか、靭性なと他の特性
を低下させるようになるので上限含有量は４％とする。WOW is also effective in coexisting with 1% or more Ni to improve corrosion resistance in a wet carbon dioxide environment, but adding more than 4% not only saturates the effect, but also improves toughness and other properties. Therefore, the upper limit content is set at 4%.
Ｖ、 Ｔｉ、 Ｎｂ、 Ｔａ、 Ｚｒ、 Ｏｆ ： Ｖ
、Ｔｉ、 Ｎｂ、 Ｔａ、 Ｚｒ。V, Ti, Nb, Ta, Zr, Of: V
, Ti, Nb, Ta, Zr.
Ｈｆは耐食性を一段と向上させるのに有効な元素である
が、Ｔｉ、 Ｚｒ、 Ｔａ、 Ｈｆでは０．２％、Ｖ、
Ｎｂでは０、５％をそれぞれ超えて添加すると粗大な析
出物・介在物を生成して硫化水素含有環境における割れ
抵抗を低下させるようになるので上限含有量はＴｉ、
Ｚｒ、 Ｔａ、 Ｈｆでは０．２％、Ｖ、Ｎｂでは０．
５％とした。Hf is an effective element to further improve corrosion resistance, but Ti, Zr, Ta, and Hf contain 0.2%, V,
If Nb is added in excess of 0% or 5%, coarse precipitates and inclusions will be formed, reducing cracking resistance in an environment containing hydrogen sulfide, so the upper limit content is Ti,
0.2% for Zr, Ta, and Hf, and 0.2% for V and Nb.
It was set at 5%.
Ｃａ、希土類元素：Ｃａおよび希土類元素（ＲＥＭ）は
熱間加工性の向上、耐食性の向上に効果のある元素であ
るが、Ｃａはｏ、 ｏ ｏ ｓ％を超えて、希土類元素
は０．０２％を超えて添加すると、それぞれ粗大な非金
属介在物を生威して逆に熱間加工性および耐食性を劣化
させるので、上限含有量はＣａはｏ、 ｏ ｏ ｓ％、
希土類元素は０．０２％とした。なお、本発明において
希土類元素とは原子番号が５７〜７１番および８９〜１
０３番の元素およびＹを指す。Ca, rare earth elements: Ca and rare earth elements (REM) are elements that are effective in improving hot workability and corrosion resistance, but Ca exceeds o, o o s%, and rare earth elements exceed 0.02 If Ca is added in excess of 0%, coarse non-metallic inclusions will form and the hot workability and corrosion resistance will deteriorate, so the upper limit of the content is 0%, 0%, 0%,
The rare earth element content was 0.02%. In addition, in the present invention, rare earth elements are those having atomic numbers of 57 to 71 and 89 to 1.
Refers to element number 03 and Y.
上記の成分を有するステンレス鋼を熱処理してマルテン
サイト組織とし所定の強度を付与するに際し、オーステ
ナイト化温度を９００〜１１００°Ｃとしたのは、９０
０″Ｃより低い温度ではオーステナイト化が充分ではな
く従って必要な強度を得ることが困難だからであり、オ
ーステナイト化温度が１１００°Ｃを超えると結晶粒が
著しく粗大化して硫化水素含有環境における割れ抵抗が
低下するようになるので、オーステナイト化温度は９０
０−１１００℃とした。When heat-treating stainless steel having the above components to form a martensitic structure and imparting a predetermined strength, the austenitizing temperature was set at 900 to 1100°C.
This is because at temperatures lower than 0"C, austenitization is insufficient and it is therefore difficult to obtain the necessary strength. When the austenitization temperature exceeds 1100C, the crystal grains become significantly coarsened, resulting in poor cracking resistance in hydrogen sulfide-containing environments. starts to decrease, so the austenitizing temperature is 90
The temperature was 0-1100°C.
オーステナイト化後の冷却における冷却速度を空冷以上
の冷却速度としたのは、空冷よりも遅い冷却速度ではマ
ルテンサイトが充分生成せず、所定の強度を確保するこ
とが困難になるからである。The reason why the cooling rate in cooling after austenitization is set to be higher than air cooling is because martensite is not sufficiently generated at a cooling rate slower than air cooling, making it difficult to secure a predetermined strength.
焼戻し温度を５６０°Ｃ以上Ａｃ＋温度以下としたのは
、焼戻し温度が５６０°Ｃ未満では充分な焼戻しが行わ
れず、焼戻し温度がＡ ｃ １温度を超えると一部がオ
ーステナイト化しその後の冷却時にフレッシュ・マルテ
ンサイトを生威し、いずれも充分に焼戻しされていない
マルテンサイトが残留するために硫化水素含有環境にお
ける割れ感受性を増加させるためである。The reason why the tempering temperature is set to 560°C or higher and lower than Ac+ temperature is because if the tempering temperature is lower than 560°C, sufficient tempering will not occur, and if the tempering temperature exceeds Ac 1 temperature, part of it will become austenite and will not be freshened during subsequent cooling. - This is because martensite is produced and martensite that has not been sufficiently tempered remains, increasing cracking susceptibility in an environment containing hydrogen sulfide.
焼戻し後の冷却における冷却速度を空冷以上の冷却速度
としたのは、空冷よりも遅い冷却速度では靭性が低下す
るためである。The reason why the cooling rate in cooling after tempering was set to be higher than air cooling is because toughness decreases at a cooling rate slower than air cooling.
本発明鋼は、通常の熱間圧延によって鋼板として使用す
ることが可能であるし、熱間押出あるいは熱間圧延によ
って鋼管として使用することも可能であるし、棒あるい
は線として使用することも勿論可能である。本発明鋼は
、油井管あるいはラインパイプとしての用途のほか、パ
ルプやポンプの部品としてなど多くの用途がある。The steel of the present invention can be used as a steel plate by ordinary hot rolling, can be used as a steel pipe by hot extrusion or hot rolling, and of course can be used as a bar or wire. It is possible. In addition to being used as oil country tubular goods or line pipes, the steel of the present invention has many uses such as pulp and pump parts.
（実施例） 以下に本発明の実施例について説明する。(Example) Examples of the present invention will be described below.
第１表に示す職分のステンレス鋼を溶製し、熱間圧延に
よって厚さ１２ａｉの鋼板とした後、第１表に併せて示
す条件で焼入れ焼戻し処理を施していずれも０．２％オ
フセット耐力が５６ｋｇ／−以上の高強度ステンレス鋼
とした。なお、第１表中の焼戻し温度はいずれも基調の
Ａ ｃ １温度以下の温度である。次にこれらの鋼材か
ら試験片を採取して湿潤炭酸ガス環境における腐食試験
、および硫化水素含有環境における割れ試験（ＳＣＣ試
験）を行なった。湿潤炭酸ガス環境における腐食試験と
しては、厚さ３ａｎ、幅１５閣、長さ５０ｍｍの試験片
を用い、試験温度１５０ ’Ｃおよび２００℃のオート
クレーブ中で炭酸ガス分圧４０気圧の条件で１５％Ｎａ
Ｃ１水溶液中に３０日間浸漬して、試験前後の重量変化
から腐食速度を算出した。腐食速度の単位はｆｆａＩｌ
／ｙで表示したが、−船釣にある環境におけるある材料
の腐食速度が０．１ ｍ／ ｙ以下の場合、材料は十分
耐食的であり使用可能であると考えられている。硫化水
素含有環境における割れ試験としては、ＮＡＣＥ （米
国腐食技術者協会）の定めている標準試験法であるＮＡ
ＣＩＩ！規格ＴＭ ０１７７に従って試験したが、硫化
水素分圧は０．１気圧、試験温度は１２０°Ｃとした。Stainless steel for the work shown in Table 1 is melted and hot-rolled into a steel plate with a thickness of 12 ai, and then quenched and tempered under the conditions shown in Table 1, each with a 0.2% offset. It was made of high-strength stainless steel with a yield strength of 56 kg/- or more. In addition, all the tempering temperatures in Table 1 are temperatures below the basic A c 1 temperature. Next, test pieces were taken from these steel materials and subjected to a corrosion test in a humid carbon dioxide environment and a cracking test (SCC test) in an environment containing hydrogen sulfide. For the corrosion test in a humid carbon dioxide environment, a test piece with a thickness of 3 an, a width of 15 mm, and a length of 50 mm was used, and the test temperature was 150'C in an autoclave at 200°C under the conditions of a carbon dioxide gas partial pressure of 40 atm. Na
It was immersed in a C1 aqueous solution for 30 days, and the corrosion rate was calculated from the weight change before and after the test. The unit of corrosion rate is ffaIl
/y, but - if the corrosion rate of a material in a boat fishing environment is less than 0.1 m/y, the material is considered to be sufficiently corrosion resistant and usable. For cracking tests in hydrogen sulfide-containing environments, NA is the standard test method established by NACE (American Society of Corrosion Engineers).
CII! Tested according to standard TM 0177, hydrogen sulfide partial pressure was 0.1 atm and test temperature was 120°C.
上記の条件で５％ＮａＣ１＋０．５％酢酸水溶液中にセ
ットした試験片に一定の単軸引張応力を負荷し、７２０
時間以内に破断するか否かを調べた。試験応力は各鋼材
の０．２％オフセット耐力の６０％の値とした。A constant uniaxial tensile stress was applied to the test piece set in 5% NaCl + 0.5% acetic acid aqueous solution under the above conditions, and 720
We investigated whether it would break within a certain amount of time. The test stress was set to a value of 60% of the 0.2% offset proof stress of each steel material.
試験結果を第１表に併せて示した。第１表のうち、腐食
試験結果において◎は腐食速度が０．０５ｍｍ／ｙ未満
、○は腐食速度が０．０５ ｗ／ ７以上０、１０ ｙ
ｍ／ ｙ未満、×は腐食速度が０．１ ｒｔｒｍ／ ７
以上０．５Ｍ／３Ｆ未満、××は腐食速度が０．５ ｗ
／ ７以上であったことをそれぞれ表わしており、割れ
試験結果（ＳＣＣ試験結果）において◎は破断しなかっ
たもの、×は破断したものをそれぞれ表わしている。な
お、第１表において、比較鋼のＮα２９はＡｌ５Ｉ４２
０鋼であり、Ｎ（Ｌ３０は９Ｃｒ−ＩＭｏ鋼であって、
いずれも従来から湿潤炭酸ガス環境で使用されている従
来鋼である。The test results are also shown in Table 1. In Table 1, in the corrosion test results, ◎ means the corrosion rate is less than 0.05 mm/y, ○ means the corrosion rate is 0.05 w/7 or more 0, 10 y
Less than m/y, × indicates corrosion rate of 0.1 rtrm/7
More than 0.5M/3F, XX indicates corrosion rate of 0.5W
/ 7 or higher, and in the cracking test results (SCC test results), ◎ indicates that the crack did not break, and × indicates that it did. In addition, in Table 1, Nα29 of the comparative steel is Al5I42
0 steel, N(L30 is 9Cr-IMo steel,
All of these are conventional steels that have been used in humid carbon dioxide environments.
第１表から明らかなように本発明鋼であるｍＮα１〜２
日は、湿潤炭酸ガス環境において２００°Ｃという従来
のマルテンサイト系ステンレス鋼では考えられないよう
な高温で、かつ１５％ＮａＣ１というＣＩ−イオン濃度
が非常に高い環境であっても、実用的に使用可能な腐食
速度である０、１ｍｍ／ｙよりも腐食速度が小さく、か
つ硫化水素含有環境における割れ試験においても破断し
ていないことから、優れた耐食性と耐応力腐食割れ性を
有していることがわかる。これに対して比較鋼であるｔ
Ｍ Ｎ（Ｌ２９〜３４は湿潤炭酸ガス環境において１５
０°Ｃでも既に腐食速度が０．１ ｔｍ／ ｙを大きく
上回っており、かつ硫化水素含有環境における割れ試験
において破断している。As is clear from Table 1, mNα1-2 of the steel of the present invention
Even in a humid carbon dioxide environment at a high temperature of 200°C, which is unimaginable for conventional martensitic stainless steel, and an environment with an extremely high CI-ion concentration of 15% NaCl, it can be used practically. The corrosion rate is lower than the usable corrosion rate of 0.1 mm/y, and it did not break even in a cracking test in an environment containing hydrogen sulfide, so it has excellent corrosion resistance and stress corrosion cracking resistance. I understand that. On the other hand, the comparison steel t
M N (L29-34 is 15 in a humid carbon dioxide environment
Even at 0°C, the corrosion rate was already much higher than 0.1 tm/y, and it fractured in a cracking test in an environment containing hydrogen sulfide.
（発明の効果）
以上述べたように、本発明は湿潤炭酸ガス環境における
優れた耐食性と湿潤硫化水素による割れに対して高い割
れ抵抗を有する鋼およびその製造方法を提供することを
可能としたものであり、産業の発展に貢献するところ極
めて大である。(Effects of the Invention) As described above, the present invention makes it possible to provide a steel having excellent corrosion resistance in a wet carbon dioxide environment and high cracking resistance against cracking caused by wet hydrogen sulfide, and a method for manufacturing the same. Therefore, it is extremely important to contribute to the development of industry.
２５３−253-
Claims (7)
特徴とする耐食性の優れたマルテンサイト系ステンレス
鋼。(1) In weight%, C is reduced to less than 0.03%, Si 1% or less, Mn 2% or less, Cr more than 15% and 18% or less, Ni 1-5%, Al 0.005-0.2%, N0.03 A martensitic stainless steel with excellent corrosion resistance, characterized by containing ~0.15% and the remainder consisting of Fe and unavoidable impurities.
れたマルテンサイト系ステンレス鋼。(2) The martensitic stainless steel with excellent corrosion resistance according to claim 1, characterized in that among the inevitable impurities, P is reduced to 0.025% or less and S is reduced to 0.010% or less.
食性の優れたマルテンサイト系ステンレス綱。(3) The martensitic stainless steel steel with excellent corrosion resistance according to claim 1 or 2, characterized in that among the inevitable impurities, O is reduced to 0.004% or less by weight.
請求項１、２または３記載の耐食性の優れたマルテンサ
イト系ステンレス鋼。(4) Excellent corrosion resistance according to claim 1, 2 or 3, characterized in that the additional component contains one or more of Cu 1% or less, Mo 2% or less, and W 4% or less, in weight percent. Martensitic stainless steel.
請求項１、２、３または４記載の耐食性の優れたマルテ
ンサイト系ステンレス鋼。(5) As an additional component, one of the following in weight%: V 0.5% or less, Ti 0.2% or less, Nb 0.5% or less, Zr 0.2% or less, Ta 0.2% or less, Hf 0.2% or less The martensitic stainless steel with excellent corrosion resistance according to claim 1, 2, 3, or 4, characterized in that it contains at least two or more kinds of martensitic stainless steel.
項１、２、３、４または５記載の耐食性の優れたマルテ
ンサイト系ステンレス鋼。(6) Claim 1, 2, 3, 4, or 5, characterized in that the additional component contains one or two of Ca0.008% or less and rare earth element 0.02% or less in weight percent. Martensitic stainless steel with excellent corrosion resistance.
ンサイト系ステンレス鋼を、９００〜１１００℃でオー
ステナイト化した後、空冷以上の冷却速度で冷却し、次
いで５６０℃以上Ａｃ＿１温度以下の温度で焼戻し処理
を施した後、空冷以上の冷却速度で冷却することを特徴
とする耐食性の優れたマルテンサイト系ステンレス鋼の
製造方法。(7) The martensitic stainless steel according to claim 1, 2, 3, 4, 5 or 6 is austenitized at 900 to 1100°C, then cooled at a cooling rate higher than air cooling, and then at Ac_1 temperature of 560°C or higher. A method for producing martensitic stainless steel with excellent corrosion resistance, which comprises tempering at a temperature below and then cooling at a cooling rate higher than air cooling.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21104789A JP2742949B2 (en) | 1989-08-16 | 1989-08-16 | Martensitic stainless steel excellent in corrosion resistance and method for producing the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21104789A JP2742949B2 (en) | 1989-08-16 | 1989-08-16 | Martensitic stainless steel excellent in corrosion resistance and method for producing the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0375336A true JPH0375336A (en) | 1991-03-29 |
| JP2742949B2 JP2742949B2 (en) | 1998-04-22 |
Family
ID=16599504
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP21104789A Expired - Fee Related JP2742949B2 (en) | 1989-08-16 | 1989-08-16 | Martensitic stainless steel excellent in corrosion resistance and method for producing the same |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2742949B2 (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH05255734A (en) * | 1991-11-22 | 1993-10-05 | Nippon Steel Corp | Production of martensitic stainless steel minimal in cracking sensitivity |
| WO2005042793A1 (en) * | 2003-10-31 | 2005-05-12 | Jfe Steel Corporation | High strength stainless steel pipe for line pipe excellent in corrosion resistance and method for production thereof |
| EP1662015A1 (en) * | 2003-08-19 | 2006-05-31 | JFE Steel Corporation | High strength stainless steel pipe excellent in corrosion resistance for use in oil well and method for production thereof |
| WO2014030392A1 (en) * | 2012-08-24 | 2014-02-27 | エヌケーケーシームレス鋼管株式会社 | Highly strong, highly tough and highly corrosion-resistant martensitic stainless steel |
| JP2015110822A (en) * | 2012-12-21 | 2015-06-18 | Ｊｆｅスチール株式会社 | High strength seamless stainless steel tube for oil well, having excellent corrosion resistance, and method for manufacturing the same |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6793744B1 (en) | 2000-11-15 | 2004-09-21 | Research Institute Of Industrial Science & Technology | Martenstic stainless steel having high mechanical strength and corrosion |
-
1989
- 1989-08-16 JP JP21104789A patent/JP2742949B2/en not_active Expired - Fee Related
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH05255734A (en) * | 1991-11-22 | 1993-10-05 | Nippon Steel Corp | Production of martensitic stainless steel minimal in cracking sensitivity |
| EP1662015A1 (en) * | 2003-08-19 | 2006-05-31 | JFE Steel Corporation | High strength stainless steel pipe excellent in corrosion resistance for use in oil well and method for production thereof |
| EP1662015A4 (en) * | 2003-08-19 | 2006-11-08 | Jfe Steel Corp | High strength stainless steel pipe excellent in corrosion resistance for use in oil well and method for production thereof |
| US7767037B2 (en) | 2003-08-19 | 2010-08-03 | Jfe Steel Corporation | High strength stainless steel pipe for use in oil well having superior corrosion resistance and manufacturing method thereof |
| WO2005042793A1 (en) * | 2003-10-31 | 2005-05-12 | Jfe Steel Corporation | High strength stainless steel pipe for line pipe excellent in corrosion resistance and method for production thereof |
| EP1683885A1 (en) * | 2003-10-31 | 2006-07-26 | JFE Steel Corporation | High strength stainless steel pipe for line pipe excellent in corrosion resistance and method for production thereof |
| EP1683885A4 (en) * | 2003-10-31 | 2007-01-03 | Jfe Steel Corp | High strength stainless steel pipe for line pipe excellent in corrosion resistance and method for production thereof |
| US7862666B2 (en) | 2003-10-31 | 2011-01-04 | Jfe Steel Corporation | Highly anticorrosive high strength stainless steel pipe for linepipe and method for manufacturing same |
| WO2014030392A1 (en) * | 2012-08-24 | 2014-02-27 | エヌケーケーシームレス鋼管株式会社 | Highly strong, highly tough and highly corrosion-resistant martensitic stainless steel |
| EP2889390A4 (en) * | 2012-08-24 | 2016-05-11 | Nkk Tubes | Highly strong, highly tough and highly corrosion-resistant martensitic stainless steel |
| JP2015110822A (en) * | 2012-12-21 | 2015-06-18 | Ｊｆｅスチール株式会社 | High strength seamless stainless steel tube for oil well, having excellent corrosion resistance, and method for manufacturing the same |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2742949B2 (en) | 1998-04-22 |
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