JP3088482B2 - Steel material for line pipes with excellent carbon dioxide gas corrosion resistance - Google Patents
Steel material for line pipes with excellent carbon dioxide gas corrosion resistanceInfo
- Publication number
- JP3088482B2 JP3088482B2 JP03114488A JP11448891A JP3088482B2 JP 3088482 B2 JP3088482 B2 JP 3088482B2 JP 03114488 A JP03114488 A JP 03114488A JP 11448891 A JP11448891 A JP 11448891A JP 3088482 B2 JP3088482 B2 JP 3088482B2
- Authority
- JP
- Japan
- Prior art keywords
- less
- carbon dioxide
- dioxide gas
- corrosion resistance
- 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.)
- Expired - Lifetime
Links
Landscapes
- Rigid Pipes And Flexible Pipes (AREA)
- Heat Treatment Of Steel (AREA)
Description
【0001】[0001]
【産業上の利用分野】本発明は炭酸ガスを含むガス(天
然ガス等)や原油等の輸送に使用して好適な耐炭酸ガス
腐食性に優れるラインパイプ用鋼材に関するものであ
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steel material for line pipes having excellent carbon dioxide corrosion resistance, which is suitable for use in transporting gas containing carbon dioxide (natural gas or the like) or crude oil.
【0002】[0002]
【従来の技術】従来炭酸ガスを含む原油、天然ガスを輸
送するパイプラインでは炭酸ガス腐食を防ぐためにイン
ヒビター(主としてアミン系)を搬送物中に添加して使
用してきた。しかし、インヒビターは必ずしもパイプラ
インの全ての場所で効率良く働かないこと、またインヒ
ビター注入装置にトラブルが発生したときなどに充分な
対応ができないなどの問題が多い。2. Description of the Related Art Conventionally, in pipelines for transporting crude oil and natural gas containing carbon dioxide, an inhibitor (mainly an amine type) has been added to a conveyed product in order to prevent carbon dioxide corrosion. However, there are many problems that the inhibitor does not always work efficiently in all places of the pipeline and that it is not possible to sufficiently cope with a trouble occurring in the inhibitor injection device.
【0003】材料そのものの耐食性を向上させる手段と
してはステンレス鋼あるいは高合金鋼を用いることはで
きるが、高価なこと、あるいは硫化水素が混ざった場合
に硫化物応力腐食われを生じるなどの問題がある。さら
に、pHの高い環境で流速が存在するとメサコロージョン
(Mesa Corrosion)と呼ばれる局部腐食が生じる問題が
ある。メサコロージョンは局部的に腐食が進行するた
め、全面腐食以上に問題が大きい。[0003] As a means for improving the corrosion resistance of the material itself, stainless steel or high alloy steel can be used. However, there is a problem that it is expensive or sulfide stress corrosion occurs when hydrogen sulfide is mixed. . Furthermore, if a flow velocity exists in a high pH environment, there is a problem that local corrosion called Mesa Corrosion occurs. Mesacorrosion is locally more corrosive and therefore more problematic than overall corrosion.
【0004】一方、耐炭酸ガス腐食性を向上させる元素
としてはCrがあり、Cr添加による油井管は、例えば特開
昭55−128566号公報で、あるいはCr添加によるラインパ
イプは、例えば特開昭56-93856号公報、特開昭55−1582
53号公報などで開示されている。ところが、Crの添加は
溶接性を低下させるためCrのみでメサコロージョンを完
全に防ぐだけの量を添加すると溶接部の硬度の大幅な上
昇を引き起こし、現実の使用には問題も多い。[0004] On the other hand, Cr is an element for improving the carbon dioxide gas corrosion resistance, and an oil country tubular good by adding Cr is disclosed in, for example, JP-A-55-128566. 56-93856, JP-A-55-1582
No. 53, for example. However, since the addition of Cr lowers the weldability, the addition of Cr only in an amount sufficient to completely prevent mesa corrosion causes a significant increase in the hardness of the welded portion, and there are many problems in actual use.
【0005】[0005]
【発明が解決しようとする課題】本発明は炭酸ガスを含
む環境で使用されるパイプラインにおいてメサコロージ
ョンを防止できる鋼材を提供することを目的とする。SUMMARY OF THE INVENTION An object of the present invention is to provide a steel material capable of preventing mesa corrosion in a pipeline used in an environment containing carbon dioxide gas.
【0006】[0006]
【課題を解決するための手段】本発明は、重量%におい
て、C:0.25%以下、Si:0.01〜0.50%、Mn: 0.1〜2.
0 %、P:0.03%以下、S:0.01%以下、Cr:0.25〜1.
0 %、Al:0.01〜0.10%を含み、さらに必要に応じて、
Ti: 0.2%以下、Nb: 0.2%以下、V: 0.2%以下、
B:0.05%以下、Zr: 0.2%以下、Ca: 0.006%以下の
うち1種又は2種以上を含有し、さらにCuを必須成分と
し、NiおよびMoを必要に応じて以下の範囲で含み、残部
がFeおよび不可避的不純物からなる耐炭酸ガス腐食性に
優れるラインパイプ用鋼材である。According to the present invention, C: 0.25% or less, Si: 0.01 to 0.50%, Mn: 0.1 to 2.% by weight.
0%, P: 0.03% or less, S: 0.01% or less, Cr: 0.25 to 1.
0%, Al: 0.01 to 0.10%, and if necessary,
Ti: 0.2% or less, Nb: 0.2% or less, V: 0.2% or less,
B: 0.05% or less, Zr: 0.2% or less, Ca: 0.006% or less, contains one or more kinds, further contains Cu as an essential component, and contains Ni and Mo as necessary in the following ranges, The balance is a steel material for line pipes that is excellent in carbon dioxide gas corrosion resistance and is composed of Fe and unavoidable impurities.
【0007】2<10Cu+Ni+3Mo 10Cu+Ni+3Mo<12Cr2 <10Cu + Ni + 3Mo 10Cu + Ni + 3Mo <12Cr
【0008】[0008]
【作 用】まず本発明における成分の限定理由を述べ
る。 C:0.25%以下 Cは強度を上げる元素として必要であるが、0.25%を超
えると溶接部の靭性を損なうので0.25%以下とした。[Operation] First, the reasons for limiting the components in the present invention will be described. C: 0.25% or less C is necessary as an element for increasing the strength, but if it exceeds 0.25%, the toughness of the welded portion is impaired.
【0009】Si:0.01〜0.50% Siは脱酸上必要な元素であるが、0.01%に満たない場合
は脱酸効果がなく、0.50%を超すと鋼の靭性を劣化させ
るので0.01〜0.50%の範囲に限定した。 Mn: 0.1〜2.0 % Mnは強度を確保する上で必要であり 0.1%以上の添加が
必要であるが、 2.0%を超えると靭性および溶接性が劣
化するので 0.1〜2.0 %の範囲に限定した。Si: 0.01 to 0.50% Si is an element necessary for deoxidation, but if it is less than 0.01%, there is no deoxidizing effect, and if it exceeds 0.50%, the toughness of the steel is deteriorated, so that 0.01 to 0.50% Limited to the range. Mn: 0.1 to 2.0% Mn is necessary to secure strength and needs to be added in an amount of 0.1% or more. However, if it exceeds 2.0%, toughness and weldability deteriorate, so it was limited to the range of 0.1 to 2.0%. .
【0010】P:0.03%以下 Pは有害な不純物元素であり、また偏析して中心偏析の
形成を促進するので少ない方がよいが、製造コストとの
関係で0.03%以下とした。 S:0.01%以下 Sは靭性および耐食性を劣化させるので少ない方がよい
が、製造コストとの関係で0.01%以下とした。P: 0.03% or less P is a harmful impurity element, and it is preferable that P is small because it segregates and promotes the formation of center segregation. However, P is set to 0.03% or less in relation to manufacturing cost. S: 0.01% or less S is preferable to be small because S deteriorates toughness and corrosion resistance, but is set to 0.01% or less in relation to manufacturing cost.
【0011】Cr:0.25〜1.0 % Crは耐炭酸ガス腐食性を著しく向上させ、0.25%以上の
添加でその効果が顕著になるが、 1.0%を超えて添加し
ても添加量に見合うほどの効果は見られず、かつ鋼の機
械的性質および溶接性(特に現地での円周溶接性)を低
下させるので 1.0%以下とした。Cr: 0.25% to 1.0% Cr remarkably improves carbon dioxide corrosion resistance, and its effect becomes remarkable when added at 0.25% or more. Since no effect was observed and the mechanical properties and weldability of steel (particularly, girth weldability in the field) were reduced, the content was set to 1.0% or less.
【0012】Al:0.01〜0.10% Alは脱酸上必要であるが、0.01%未満ではその効果がな
く、0.10%を超すと結晶粒の粗大化を引き起こして材質
を劣化させるなど好ましくないので0.01〜0.10%の範囲
に限定した。 2<10Cu+Ni+3Mo …(数1) 10Cu+Ni+3Mo<12Cr …(数2) Cu、Ni、Moは鋼の表面を平滑にし、メサコロージョンを
防ぐ働きをする。特にCuはその働きが強く必須成分と
し、NiおよびMoは必要に応じて数1の範囲を満足するよ
うに添加することにより、メサコロージョンを防止でき
る。しかしながら数2の範囲を超えて添加するとCrの効
果がうすれて全面腐食速度が増加するため上記の範囲内
に限定した。Al: 0.01 to 0.10% Al is necessary for deoxidation, but if it is less than 0.01%, it has no effect. If it exceeds 0.10%, crystal grains become coarse and the material is deteriorated. Limited to the range of ~ 0.10%. 2 <10Cu + Ni + 3Mo (Equation 1) 10Cu + Ni + 3Mo <12Cr (Equation 2) Cu, Ni, and Mo smoothen the surface of steel and prevent mesa corrosion. In particular, Cu has a strong function and is an essential component, and Ni and Mo can be added so as to satisfy the range of Formula 1 as needed, thereby preventing mesa corrosion. However, if it is added beyond the range of the formula 2, the effect of Cr is weakened and the overall corrosion rate increases, so that it was limited to the above range.
【0013】Ti: 0.2%以下 Nb: 0.2%以下 V: 0.2%以下 B: 0.005%以下 上記の元素はいずれも強度を上げるのに効果があり、必
要に応じて添加できるが、いずれも上限を超えると靭性
の低下を引き起こすので上記のように限定した。Ti: 0.2% or less Nb: 0.2% or less V: 0.2% or less B: 0.005% or less Any of the above elements is effective in increasing the strength, and can be added as necessary. Exceeding this causes a decrease in toughness, so it was limited as described above.
【0014】Zr:0.20%以下 Ca: 0.006%以下 Zr、Caは介在物の形態制御ならびに微量の硫化水素が存
在する場合の水素誘起われを防止するのに効果があり、
必要に応じて添加できるが、いずれも上限を超えて添加
すると靭性の劣化を引き起こすので上記のように限定し
た。Zr: 0.20% or less Ca: 0.006% or less Zr and Ca are effective in controlling the morphology of inclusions and preventing hydrogen-induced cracking in the presence of a small amount of hydrogen sulfide.
Although it can be added as needed, addition of any of them exceeding the upper limit causes deterioration of toughness, so that the content is limited as described above.
【0015】[0015]
【実施例】Cレベルを変えた従来鋼にCr、Cu、Ni、Mo量
を変化させて添加し、耐食性を調査した。供試材の化学
組成を表1、表2に示す。供試材の機械的性質は表3中
に示す。これらの鋼から5mm×50mm× 100mmの試験片を
採取し、腐食試験に供した。試験条件は人工海水中、炭
酸ガス分圧 0.1MPa、温度50℃、流速1m/sec であ
る。試験装置の模式図を図1に示す。試験時間は1カ月
とし、試験後重量測定によって全面腐食速度を求めると
同時に表面観察にてメサコロージョンの有無を調べた。
その結果、本発明鋼は全て全面腐食速度が2.25mm/yr以
下であり、かつメサコロージョンも発生していない。一
方比較鋼17、18、21、23のようにCr量が0.25%以下であ
れば腐食速度は大きい。また、18、23、24のように10Cu
+Ni+3Moが2以下であればメサコロージョンが発生
し、腐食速度も大きくなる。また22のように10Cu+Ni+
3Moが2以上であり、かつCrが0.25%以上添加されてい
ても10Cu+Ni+3Moが12Crより多いと全面腐食速度が大
きくなる。EXAMPLE The corrosion resistance was investigated by adding Cr, Cu, Ni, and Mo with varying amounts to conventional steel with varying C levels. Tables 1 and 2 show the chemical compositions of the test materials. Table 3 shows the mechanical properties of the test materials. Specimens of 5 mm × 50 mm × 100 mm were collected from these steels and subjected to a corrosion test. The test conditions were artificial seawater, carbon dioxide gas partial pressure of 0.1 MPa, temperature of 50 ° C., and flow rate of 1 m / sec. FIG. 1 shows a schematic diagram of the test apparatus. The test time was one month. After the test, the overall corrosion rate was determined by weight measurement, and the presence or absence of mesa corrosion was examined by surface observation.
As a result, all of the steels of the present invention have an overall corrosion rate of 2.25 mm / yr or less and have no mesa corrosion. On the other hand, when the Cr content is 0.25% or less as in Comparative Steels 17, 18, 21, and 23, the corrosion rate is high. Also, 10Cu like 18, 23, 24
If + Ni + 3Mo is 2 or less, mesa corrosion occurs and the corrosion rate increases. 10Cu + Ni + like 22
Even if 3Mo is 2 or more and Cr is added at 0.25% or more, if 10Cu + Ni + 3Mo is more than 12Cr, the overall corrosion rate increases.
【0016】[0016]
【表1】 [Table 1]
【0017】[0017]
【表2】 [Table 2]
【0018】[0018]
【表3】 [Table 3]
【0019】[0019]
【発明の効果】本発明の鋼材を用いることにより、炭酸
ガスを含む環境で全面腐食速度を低下させると同時にメ
サコロージョンを防止できることが明らかになった。It has been clarified that the use of the steel material of the present invention makes it possible to reduce the overall corrosion rate in an environment containing carbon dioxide gas and at the same time to prevent mesa corrosion.
【図1】耐食性試験装置の模式図である。FIG. 1 is a schematic view of a corrosion resistance test apparatus.
フロントページの続き (56)参考文献 特開 昭61−130460(JP,A) 特開 平3−110071(JP,A) 特開 昭58−193350(JP,A) 特開 昭62−54022(JP,A) 特開 昭52−131923(JP,A) 特開 昭52−128821(JP,A) (58)調査した分野(Int.Cl.7,DB名) C22C 38/00 301 C22C 38/44 Continuation of the front page (56) References JP-A-61-130460 (JP, A) JP-A-3-110071 (JP, A) JP-A-58-193350 (JP, A) JP-A-62-54022 (JP, A) JP-A-52-131923 (JP, A) JP-A-52-128821 (JP, A) (58) Fields investigated (Int. Cl. 7 , DB name) C22C 38/00 301 C22C 38/44
Claims (2)
0.01〜0.50%、Mn:0.1〜2.0 %、P:0.03%以下、
S:0.01%以下、Cr:0.25〜1.0%、Al:0.01〜0.10%
を含み、さらにCuを必須成分とし、NiおよびMoを必要に
応じて以下の範囲で含み、残部がFeおよび不可避的不純
物からなる耐炭酸ガス腐食性に優れるラインパイプ用鋼
材。 2<10Cu+Ni+3Mo 10Cu+Ni+3Mo<12Cr(1) In weight%, C: 0.25% or less, Si:
0.01 to 0.50%, Mn: 0.1 to 2.0%, P: 0.03% or less,
S: 0.01% or less, Cr: 0.25 to 1.0%, Al: 0.01 to 0.10%
Further, a steel material for line pipes which contains Cu as an essential component, contains Ni and Mo in the following ranges as required, and has a balance of Fe and unavoidable impurities, and has excellent carbon dioxide gas corrosion resistance. 2 <10Cu + Ni + 3Mo 10Cu + Ni + 3Mo <12Cr
0.01〜0.50%、Mn:0.1〜2.0 %、P:0.03%以下、
S:0.01%以下、Cr:0.25〜1.0%、Al:0.01〜0.10%
を含み、加えて、Ti: 0.2%以下、Nb: 0.2%以下、
V: 0.2%以下、B:0.05%以下、Zr: 0.2%以下、C
a: 0.006%以下のうち1種又は2種以上を含有し、さ
らにCuを必須成分とし、NiおよびMoを必要に応じて以下
の範囲で含み、残部がFeおよび不可避的不純物からなる
耐炭酸ガス腐食性に優れるラインパイプ用鋼材。 2<10Cu+Ni+3Mo 10Cu+Ni+3Mo<12Cr2. In% by weight, C: 0.25% or less, Si:
0.01 to 0.50%, Mn: 0.1 to 2.0%, P: 0.03% or less,
S: 0.01% or less, Cr: 0.25 to 1.0%, Al: 0.01 to 0.10%
In addition, Ti: 0.2% or less, Nb: 0.2% or less,
V: 0.2% or less, B: 0.05% or less, Zr: 0.2% or less, C
a: Carbon dioxide gas containing one or more of 0.006% or less, further containing Cu as an essential component, Ni and Mo in the following ranges as necessary, and the balance being Fe and unavoidable impurities. Excellent corrosion-resistant steel for line pipes. 2 <10Cu + Ni + 3Mo 10Cu + Ni + 3Mo <12Cr
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP03114488A JP3088482B2 (en) | 1991-05-20 | 1991-05-20 | Steel material for line pipes with excellent carbon dioxide gas corrosion resistance |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP03114488A JP3088482B2 (en) | 1991-05-20 | 1991-05-20 | Steel material for line pipes with excellent carbon dioxide gas corrosion resistance |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH04341540A JPH04341540A (en) | 1992-11-27 |
JP3088482B2 true JP3088482B2 (en) | 2000-09-18 |
Family
ID=14639011
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP03114488A Expired - Lifetime JP3088482B2 (en) | 1991-05-20 | 1991-05-20 | Steel material for line pipes with excellent carbon dioxide gas corrosion resistance |
Country Status (1)
Country | Link |
---|---|
JP (1) | JP3088482B2 (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP5446278B2 (en) * | 2009-01-14 | 2014-03-19 | Jfeスチール株式会社 | Structural steel with excellent weather resistance |
-
1991
- 1991-05-20 JP JP03114488A patent/JP3088482B2/en not_active Expired - Lifetime
Also Published As
Publication number | Publication date |
---|---|
JPH04341540A (en) | 1992-11-27 |
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