JPH0762499A - Martensitic stainless steel for oil well pipe - Google Patents
Martensitic stainless steel for oil well pipeInfo
- Publication number
- JPH0762499A JPH0762499A JP21167493A JP21167493A JPH0762499A JP H0762499 A JPH0762499 A JP H0762499A JP 21167493 A JP21167493 A JP 21167493A JP 21167493 A JP21167493 A JP 21167493A JP H0762499 A JPH0762499 A JP H0762499A
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- weight
- stainless steel
- oil well
- martensitic stainless
- resistance
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- Heat Treatment Of Steel (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、原油あるいは天然ガス
の油井、ガス井に使用される油井管用の鋼材に関し、特
に炭酸ガス（ＣＯ2)、硫化水素（Ｈ2 Ｓ）、塩素イオン
（Ｃｌ- ) などを含む極めて厳しい腐食環境の油井、ガ
ス井で使用するに適した、耐全面腐食性と硫化物存在下
での耐応力腐食割れ（Stress Corrosion Crack，「ＳＣ
Ｃ」と略称される。）性とに優れ、熱間加工性にも優れ
た油井管用マルテンサイト系ステンレス鋼に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crude oil or natural gas oil well and a steel material for oil well pipes used in gas wells, and in particular carbon dioxide (CO 2 ), hydrogen sulfide (H 2 S) and chlorine ion (Cl 2 ). - ) Suitable for use in oil wells and gas wells that have extremely severe corrosive environments, including general corrosion resistance and stress corrosion cracking in the presence of sulfides (Stress Corrosion Crack, “SC
It is abbreviated as "C". ) And martensitic stainless steel for oil country tubular goods that is also excellent in hot workability.
【０００２】[0002]
【従来の技術】近年に至り、原油価格の高騰や近い将来
に予想される石油資源の枯渇化に対応して、従来は開発
がなされなかったような深層油田や、開発が一旦は放棄
されていたサワーガス田等に対する開発が世界的規模で
盛んになっている。このような油田やガス田は一般に深
度が極めて深く、その雰囲気はＣＯ2 、Ｈ2 Ｓ、Ｃｌ-
等を含む厳しい腐食環境となっている。したがって、こ
のような油田やガス田の採掘に使用される油井管として
は、高強度でしかも耐全面腐食性と耐ＳＣＣ性を兼ね備
えた材質が要求される。2. Description of the Related Art In recent years, in response to soaring crude oil prices and depletion of petroleum resources expected in the near future, deep oil fields that have not been developed in the past, and development have been abandoned once. The development of sour gas fields is becoming popular on a global scale. Such oil fields and gas fields are generally extremely deep, and their atmospheres are CO 2 , H 2 S, Cl −.
It is a severe corrosive environment including Therefore, a material having high strength and having both general corrosion resistance and SCC resistance is required for an oil country tubular good used for mining such an oil field or gas field.
【０００３】このような苛酷な腐食環境下においては、
温度が100 ℃以下の比較的低温の環境下では13Ｃｒマル
テンサイト系ステンレス鋼を、それ以上の高温の環境下
では22Ｃｒ二相ステンレス鋼を使用することが一般的で
あったが、多くの油井は100〜150 ℃の温度環境下にあ
るため、この程度の温度環境下で高価な22Ｃｒ二相ステ
ンレス鋼を使用することは過剰防食であり、経済的でな
いという問題点があった。Under such a severe corrosive environment,
It was common to use 13Cr martensitic stainless steel in a relatively low temperature environment of 100 ° C or less and 22Cr duplex stainless steel in a higher temperature environment, but many oil wells Since it is in a temperature environment of 100 to 150 ° C., use of expensive 22Cr duplex stainless steel in such a temperature environment causes excessive corrosion protection and is not economical.
【０００４】そこで、腐食性が高く温度が100 〜150 ℃
である油井環境に適した、22Ｃｒ二相ステンレス鋼に代
わり得る安価で機械的強度も高い油井管用のステンレス
鋼として、本発明者等は、Ｃの含有割合を従来より著し
く低減した13Ｃｒ鋼にＮｉ、Ｍｏ、Ｎを添加し、さらに
Ｓｉ、Ａｌ、Ｏの含有割合を低減した油井管用マルテン
サイト系ステンレス鋼を提案した（特開平４−２２４６
５６号公報参照）。Therefore, it is highly corrosive and the temperature is 100 to 150 ° C.
As a stainless steel for oil well pipes, which is suitable for the oil well environment and can replace 22Cr duplex stainless steel, and is inexpensive and has high mechanical strength, the present inventors , Mo, N were added, and the content of Si, Al, and O was reduced, and a martensitic stainless steel for oil country tubular goods was proposed (JP-A-4-2246).
No. 56).
【０００５】このような油井管用マルテンサイト系ステ
ンレス鋼によれば、ＣＯ2 、Ｈ2 Ｓ、Ｃｌ- を含む厳し
い腐食環境下であって温度が100 〜150 ℃となる環境下
での耐全面腐食性および耐ＳＣＣ性が改善され、機械的
強度も十分に確保される。According to such martensitic stainless steel for oil country tubular goods, general corrosion resistance in a severe corrosive environment containing CO 2 , H 2 S and Cl − and at a temperature of 100 to 150 ° C. And SCC resistance are improved and mechanical strength is sufficiently ensured.
【０００６】[0006]
【発明が解決しようとする課題】しかしながら、前記油
井管用マルテンサイト系ステンレス鋼には、熱間加工性
の面で改善の余地があった。本発明は、このような事情
を背景としてなされたものであり、ＣＯ2 、Ｈ2 Ｓ、Ｃ
ｌ- を含む厳しい腐食環境下であって温度が100 〜150
℃となる環境下での耐全面腐食性および耐ＳＣＣ性が改
善され、機械的強度も十分に確保されるとともに、高い
熱間加工性をも備えた油井管用マルテンサイト系ステン
レス鋼を提供することを目的とする。However, the martensitic stainless steel for oil country tubular goods has room for improvement in terms of hot workability. The present invention has been made against the background of such circumstances, and CO 2 , H 2 S, C
l - temperature even under severe corrosive environments, including the 100-150
To provide martensitic stainless steel for oil country tubular goods which has improved general corrosion resistance and SCC resistance in an environment of ℃ and has sufficient mechanical strength as well as high hot workability. With the goal.
【０００７】[0007]
【課題を解決するための手段】上記目的を達成するため
に、本発明は、Ｃ：0.02〜0.05重量％、Ｓｉ：0.50重量
％以下、Ｍｎ：0.30〜1.20重量％、Ｐ：0.025 重量％以
下、Ｓ：0.005 重量％以下、Ｃｒ：12.0〜14.0重量％、
Ｎｉ：3.0 〜5.0 重量％、Ｍｏ：0.5 〜1.5 重量％、Ａ
ｌ:0.01 〜0.05重量％、Ｎ：0.03〜0.08重量％、Ｏ：0.
005 重量％以下、Ｂ：0.0005〜0.0100重量％を含有し、
残部がＦｅおよび不可避的不純物よりなることを特徴と
する油井管用マルテンサイト系ステンレス鋼を提供す
る。To achieve the above object, the present invention provides C: 0.02 to 0.05% by weight, Si: 0.50% by weight or less, Mn: 0.30 to 1.20% by weight, P: 0.025% by weight or less. , S: 0.005% by weight or less, Cr: 12.0-14.0% by weight,
Ni: 3.0 to 5.0% by weight, Mo: 0.5 to 1.5% by weight, A
1: 0.01 to 0.05% by weight, N: 0.03 to 0.08% by weight, O: 0.
005% by weight or less, B: 0.0005 to 0.0100% by weight,
A martensitic stainless steel for oil country tubular goods, characterized in that the balance is Fe and inevitable impurities.
【０００８】[0008]
【作用】本発明の油井管用マルテンサイト系ステンレス
鋼においては、Ｃの含有割合を従来より著しく低減した
13Ｃｒ鋼にＮｉ、Ｍｏ、Ｎを添加し、さらにＳｉ、Ａ
ｌ、Ｏの含有割合を低減するとともに、Ｂを0.0005〜0.
0100重量％の範囲で含有することにより、ＣＯ2 、Ｈ2
Ｓ、Ｃｌ- を含む厳しい腐食環境下であって温度が100
〜150 ℃となる環境下での耐全面腐食性および耐ＳＣＣ
性を損なうことなく、機械的強度も確保しながら、しか
も熱間加工性を十分に高くすることが可能となる。In the martensitic stainless steel for oil country tubular goods of the present invention, the content ratio of C is remarkably reduced as compared with the conventional one.
Addition of Ni, Mo, N to 13Cr steel, and Si, A
The content ratio of l and O is reduced and B is 0.0005 to 0.
When the content is 0100% by weight, CO 2 , H 2
S, Cl - even under severe corrosive environments including temperature of 100
General corrosion resistance and SCC resistance in an environment of ~ 150 ° C
It is possible to sufficiently improve the hot workability while ensuring the mechanical strength without deteriorating the workability.
【０００９】各成分の含有割合についての限定理由を以
下に述べる。 ＜Ｃ：0.02〜0.05重量％＞Ｃはマルテンサイト系ステン
レス鋼の機械的強度を決める重要な元素であるが、後述
のＮｉの添加によってＡｃ1 点が下がりＣ固溶量が減少
するため、焼戻し時に鋭敏化が起こりやすくなる。鋭敏
化を起こさせないためには、Ｃの含有割合を0.05重量％
以下にする必要がある。また、Ｃの含有割合を0.02重量
％未満とするには、特別な脱ガス処理が必要となるため
製造コストが著しく上昇する。The reasons for limiting the content of each component will be described below. <C: 0.02 to 0.05% by weight> C is an important element that determines the mechanical strength of martensitic stainless steel, but the addition of Ni, which will be described later, lowers the Ac 1 point and reduces the amount of C solid solution. Sometimes sensitization is more likely to occur. In order to prevent sensitization, the C content should be 0.05% by weight.
Must be: Further, if the content ratio of C is less than 0.02% by weight, a special degassing treatment is required, so that the manufacturing cost is significantly increased.
【００１０】なお、本発明では、後述するように、Ｃの
含有割合を低減したことによる機械的強度の低下を、主
にＮｉの添加によって補うこととした。 ＜Ｓｉ：0.50重量％以下＞Ｓｉは通常の製鋼過程におけ
る脱酸剤として必要な元素であるが、0.50重量％を越え
て含有するとδフェライトの発生を招き、耐食性および
熱間加工性が劣化する。In the present invention, as will be described later, the reduction of the mechanical strength due to the reduction of the C content is mainly compensated by the addition of Ni. <Si: 0.50% by weight or less> Si is an element necessary as a deoxidizing agent in the ordinary steelmaking process, but if it is contained in excess of 0.50% by weight, δ ferrite is generated, and corrosion resistance and hot workability deteriorate. .
【００１１】＜Ｍｎ：0.30〜1.20重量％＞Ｍｎは、油井
管用マルテンサイト系ステンレス鋼として必要な機械的
強度を確保するために、0.30重量％以上含有することが
必要であるが、1.20重量％を超えて含有すると靱性に悪
影響を及ぼす。 ＜Ｐ：0.025 重量％以下＞Ｐは耐全面腐食性や耐ＳＣＣ
性を劣化させる元素であり、その含有量はできるだけ少
ないことが望ましい。工業的に比較的安価に製造可能
で、耐全面腐食性や耐ＳＣＣ性の劣化が前述の油井環境
下で十分に抑制される範囲として、0.025 重量％以下に
した。<Mn: 0.30 to 1.20% by weight> Mn must be contained in an amount of 0.30% by weight or more in order to secure the mechanical strength required for martensitic stainless steel for oil country tubular goods, but 1.20% by weight. If it is contained in excess of 1.0, the toughness is adversely affected. <P: 0.025 wt% or less> P is general corrosion resistance and SCC resistance
It is an element that deteriorates the properties, and its content is preferably as low as possible. The amount is 0.025% by weight or less as a range that can be industrially manufactured at a relatively low cost and the deterioration of general corrosion resistance and SCC resistance can be sufficiently suppressed under the above-mentioned oil well environment.
【００１２】＜Ｓ：0.005 重量％以下＞Ｓは熱間加工性
を著しく劣化させる元素であり、その含有量はできるだ
け少ないことが望ましい。その限界値としてＳの含有割
合が0.005 重量％を超えると、通常の工程でのパイプ製
造が困難となる。 ＜Ｃｒ：12.0〜14.0重量％＞Ｃｒはステンレス鋼の耐食
性を保持するための主要な元素であり、耐食性の観点か
らは含有割合を12.0重量％以上とする必要があるが、含
有割合が14.0重量％を超えるとδフェライトの発生を招
き熱間加工性が劣化する。<S: 0.005% by weight or less> S is an element that significantly deteriorates hot workability, and its content is preferably as small as possible. If the content ratio of S exceeds 0.005% by weight as the limit value, pipe manufacturing in a normal process becomes difficult. <Cr: 12.0 to 14.0% by weight> Cr is a main element for maintaining the corrosion resistance of stainless steel. From the viewpoint of corrosion resistance, the content ratio is required to be 12.0% by weight or more, but the content ratio is 14.0% by weight. %, Δ ferrite is generated and hot workability deteriorates.
【００１３】＜Ｎｉ：3.0 〜5.0 重量％＞Ｎｉは耐食性
のうち特にＣＯ2 による全面腐食に対して抵抗性を与え
るとともに、Ｃの含有割合を低減した13Ｃｒ鋼の機械的
強度を上昇させるために添加されるが、3.0 重量％未満
ではその効果は認められず、5.0 重量％を超えるとマル
テンサイト組織の安定性を損なう。<Ni: 3.0 to 5.0% by weight> Ni provides corrosion resistance, particularly resistance to general corrosion due to CO 2 , and increases the mechanical strength of 13Cr steel having a reduced C content. Although it is added, its effect is not recognized at less than 3.0% by weight, and the stability of the martensitic structure is impaired at more than 5.0% by weight.
【００１４】＜Ｍｏ：0.5 〜1.5 重量％＞Ｍｏは耐食性
のうち特にＣｌ- による孔食に対して抵抗性を与える元
素であるが、0.5 重量％未満ではその効果は認められ
ず、1.5 重量％を超えるとδフェライトの発生を招いて
孔食以外の耐食性及び熱間加工性が劣化する。 ＜Ａｌ:0.01 〜0.05重量％＞Ａｌは強力な脱酸作用を有
する元素であるが、0.01重量％未満ではその効果が十分
ではなく、0.05重量％を越えると靱性に悪影響を及ぼ
す。[0014] <Mo: 0.5 to 1.5 wt%> Mo especially Cl of corrosion resistance - is an element that gives the resistance to by pitting, that effect is not observed in less than 0.5 wt%, 1.5 wt% If it exceeds 1.0, δ-ferrite is generated and corrosion resistance other than pitting corrosion and hot workability deteriorate. <Al: 0.01 to 0.05% by weight> Al is an element having a strong deoxidizing action, but if it is less than 0.01% by weight, its effect is not sufficient, and if it exceeds 0.05% by weight, toughness is adversely affected.
【００１５】＜Ｎ：0.03〜0.08重量％＞Ｎは耐食性、耐
ＳＣＣ性を著しく向上させる元素であるが、0.03重量％
未満ではその効果が十分ではなく、0.08重量％を超える
と種々の窒化物を形成して靱性を劣化させる。 ＜Ｏ：0.005 重量％以下＞Ｏを0.005 重量％を超えるほ
ど多く含有すると、各種酸化物が形成されて、熱間加工
性、耐全面腐食性、耐ＳＣＣ性、および靱性が著しく劣
化する。<N: 0.03 to 0.08% by weight> N is an element that significantly improves corrosion resistance and SCC resistance, but 0.03% by weight
If it is less than 0.08%, the effect is not sufficient, and if it exceeds 0.08% by weight, various nitrides are formed and the toughness is deteriorated. <O: 0.005 wt% or less> When O is contained in a large amount exceeding 0.005 wt%, various oxides are formed and hot workability, general corrosion resistance, SCC resistance, and toughness are significantly deteriorated.
【００１６】＜Ｂ：0.0005〜0.0100重量％＞Ｂは粒界を
強化する作用を有する元素であり、Ｂの添加により変形
時に粒界の延性が増すため熱間加工性が高くなる。ま
た、粒界に沿って進展するマルテンサイト系ステンレス
鋼の応力腐食割れを抑制する効果があるため、Ｂの添加
により耐ＳＣＣ性が向上する。これらの効果を発揮させ
るためには0.0005重量％以上の添加が必要であり、0.01
00重量％を超えて添加すると逆に脆化を引き起こすこと
になる。<B: 0.0005 to 0.0100% by weight> B is an element having a function of strengthening the grain boundary, and the addition of B increases the ductility of the grain boundary at the time of deformation, thereby improving the hot workability. Further, since it has an effect of suppressing the stress corrosion cracking of the martensitic stainless steel propagating along the grain boundary, the addition of B improves the SCC resistance. In order to exert these effects, it is necessary to add 0.0005% by weight or more.
If it is added in excess of 00% by weight, it will cause embrittlement.
【００１７】なお、この鋼によれば、熱間加工性が十分
に高いため、油井管の製造を通常の製造工程に何ら手を
加えることなく行うことができる。すなわち、例えば、
シームレスパイプあるいは電縫管に成形後、950 〜1050
°Ｃの温度範囲に加熱して水冷または空冷により冷却
し、その後、油井管として必要な強度を得るべく550 〜
700 °Ｃの温度範囲で焼戻しを行う。Since this steel has a sufficiently high hot workability, the oil country tubular goods can be manufactured without any modification to the normal manufacturing process. That is, for example,
950-1050 after forming into seamless pipe or electric resistance welded pipe
It is heated in the temperature range of ° C and cooled by water cooling or air cooling, then 550 to obtain the strength required for an oil country tubular good.
Tempering is performed in the temperature range of 700 ° C.
【００１８】[0018]
【実施例】次に、本発明の実施例について説明する。下
記の表１に示すような、試料記号Ａ〜Ｏの各化学組成を
有する鋼により、熱間加工性、耐全面腐食性、および耐
ＳＣＣ性を調べる実験を行った。すなわち、前記各鋼を
厚さ１５ｍｍの板状に熱間圧延して得られた熱延鋼板か
ら、平行部直径６ｍｍの丸棒引張試験片Ａを採取した。
また、前記厚さ１５ｍｍの熱延鋼板に対して焼きならし
および焼戻しを行い、降伏強度が表１に示す値となった
素材から、それぞれ厚さ３ｍｍ、幅３０ｍｍ、長さ４０
ｍｍの試験片Ｂと、厚さ２ｍｍ、幅２０ｍｍ、長さ７５
ｍｍの試験片Ｃを作製した。EXAMPLES Next, examples of the present invention will be described. Experiments were conducted to examine hot workability, general corrosion resistance, and SCC resistance of steels having respective chemical compositions of sample symbols A to O as shown in Table 1 below. That is, a round bar tensile test piece A having a parallel portion diameter of 6 mm was taken from a hot rolled steel sheet obtained by hot rolling each of the above steels into a plate shape having a thickness of 15 mm.
Further, the hot rolled steel sheet having a thickness of 15 mm was subjected to normalization and tempering, and from materials having yield strengths shown in Table 1, thickness 3 mm, width 30 mm, and length 40, respectively.
mm test piece B, thickness 2 mm, width 20 mm, length 75
A mm test piece C was prepared.
【００１９】熱間加工性については、試験片Ａを用い、
その両端を引張試験機のチャックに取り付けて１２５０
℃の雰囲気下に１００秒以上保持した後、雰囲気温度を
１０℃／ｓの速度で１０００℃まで下げて、その温度に
１０秒間保持した後、高速（１００ｍｍ／ｓ）で破断す
るまで引張り、これによる丸棒断面の直径減少率を算出
した。この値が６０％以上であれば、傾斜圧延法により
シームレス鋼管に加工するために十分な熱間加工性を有
するものと考えることができる。Regarding hot workability, using the test piece A,
Attach both ends to the chuck of the tensile tester and
After holding it in the atmosphere of ℃ for 100 seconds or more, lower the atmosphere temperature to 1000 ℃ at a speed of 10 ℃ / s, hold it at that temperature for 10 seconds, and pull at a high speed (100 mm / s) until it breaks. The diameter reduction rate of the round bar cross section was calculated. If this value is 60% or more, it can be considered that the steel has sufficient hot workability for processing into a seamless steel pipe by the tilt rolling method.
【００２０】耐全面腐食性については、試験片Ｂを、Ｎ
ａＣｌ濃度２０重量％、ＣＯ2 圧力３０気圧、温度１５
０℃の雰囲気下に１週間放置し、その重量減少量から腐
食速度を算出した。この値が小さいほど耐全面腐食性が
高く、０．０５０ｇ/m2h以下であれば前述の油井環境に
耐えられるものと考えることができる。耐ＳＣＣ性につ
いては、図１に示すように、試験片Ｃを曲げ治具Ｇによ
り曲率半径Ｒが８ｍｍとなるようにＵ字状に曲げた状態
に保持して、ＮａＣｌ濃度２０重量％、ＣＯ2 分圧３０
気圧、Ｈ2 Ｓ分圧：０．００７気圧、温度１５０℃の雰
囲気下に１週間放置し、（ａ）肉眼観察による割れ発生
の有無と、（ｂ）断面を光学顕微鏡で観察した時の割れ
発生の有無とで評価した。Regarding the general corrosion resistance, the test piece B was
aCl concentration 20% by weight, CO 2 pressure 30 atm, temperature 15
The sample was left in an atmosphere of 0 ° C. for 1 week, and the corrosion rate was calculated from the weight loss. The smaller this value is, the higher the general corrosion resistance is. If it is 0.050 g / m 2 h or less, it can be considered that the above-mentioned oil well environment can be endured. As for the SCC resistance, as shown in FIG. 1, the test piece C was held in a U-shape bent by a bending jig G so that the radius of curvature R was 8 mm, and the NaCl concentration was 20% by weight and CO 2 partial pressure 30
Air pressure, H 2 S partial pressure: 0.007 atm, left for 1 week in an atmosphere of 150 ° C., (a) presence or absence of cracking by visual observation, and (b) cracking when observing a cross section with an optical microscope. The presence or absence of occurrence was evaluated.
【００２１】各試験の結果を下記の表１に併せて示す。The results of each test are also shown in Table 1 below.
【００２２】[0022]
【表１】 [Table 1]
【００２３】表１から分かるように、本発明の鋼に相当
する試料記号Ｌ〜Ｏの各鋼は、腐食速度が前述の油井環
境に耐え得るための０．０５０ｇ/m2h以下となり、応力
腐食割れの発生も認められないとともに、直径減少率が
傾斜圧延法によりシームレス鋼管に加工するために十分
な６０％以上になっており、降伏強度も１００ｋｓｉ
（ｋｇｆ／ｉｎ2 ）以上と高いため、前述の腐食性が高
く１００〜１５０℃の温度となる環境下で用いられる油
井管用鋼として、十分な耐全面腐食性、耐ＳＣＣ性、お
よび熱間加工性を兼ね備えているものである。As can be seen from Table 1, each of the steels of sample symbols L to O corresponding to the steels of the present invention has a corrosion rate of 0.050 g / m 2 h or less for withstanding the above-mentioned oil well environment, and stress. No corrosion cracking was observed, the diameter reduction rate was 60% or more, which was sufficient for processing into a seamless steel pipe by the inclined rolling method, and the yield strength was 100 ksi.
Since it is as high as (kgf / in 2 ) or more, sufficient general corrosion resistance, SCC resistance, and hot working as steel for oil country tubular goods to be used under the environment where the above-mentioned corrosion is high and the temperature is 100 to 150 ° C. It has both sex.
【００２４】これに対し、本発明の組成範囲外である試
料記号Ａ〜Ｋの鋼（比較例鋼）は、以下に述べるよう
に、直径減少率が６０％に達していなかったり、腐食速
度が０．０５０ｇ/m2hより大きかったり、応力腐食割れ
が発生したりしており、耐全面腐食性、耐ＳＣＣ性、お
よび熱間加工性のすべてを兼ね備えているものはない。
すなわち、Ａ鋼は、Ｃの含有割合が０．０５３重量％と
本発明の範囲より大きいために、焼戻し時に鋭敏化が起
こって腐食速度の値が大きくなり、耐全面腐食性に劣る
ものであった。また、Ｂを含有していないが、ＳｉやＳ
の含有割合が比較的少ないため直径減少率は６０．２％
となった。On the other hand, in the steels of sample symbols A to K (comparative steels) which are out of the composition range of the present invention, the diameter reduction rate does not reach 60% or the corrosion rate is as described below. It is larger than 0.050 g / m 2 h, stress corrosion cracking occurs, and none of them have all of general corrosion resistance, SCC resistance, and hot workability.
In other words, steel A has a C content of 0.053% by weight, which is larger than the range of the present invention, and therefore sensitization occurs during tempering, resulting in a large corrosion rate and poor general corrosion resistance. It was Also, although it does not contain B, it does not contain Si or S.
The diameter reduction rate is 60.2% due to the relatively small content of
Became.
【００２５】Ｂ鋼は、Ｃｒの含有割合が１１．５重量％
と本発明の範囲より小さいために、腐食速度の値が大き
く耐全面腐食性に劣るものであった。また、Ｂを含有し
ていないがＣｒの含有割合が小さいために、直径減少率
は６１．２％となった。Ｃ鋼は、Ｍｏの含有割合が０．
３２重量％と本発明の範囲より小さいために、腐食速度
の値が大きく耐全面腐食性に劣るものであった。また、
Ｂを含有せずＮの含有割合も小さいため、顕微鏡観察と
肉眼観察の両方で応力腐食割れが認められ耐ＳＣＣ性が
十分でないものであった。さらに、Ｂを含有していない
がＳやＭｎの含有割合が小さいために、直径減少率は６
３．９％となった。Steel B has a Cr content of 11.5% by weight.
Since it was smaller than the range of the present invention, the value of the corrosion rate was large and the general corrosion resistance was poor. Further, since B was not contained, but the content ratio of Cr was small, the diameter reduction rate was 61.2%. C steel has a Mo content of 0.
Since it was 32% by weight, which was smaller than the range of the present invention, the value of the corrosion rate was large and the general corrosion resistance was poor. Also,
Since it did not contain B and the content ratio of N was small, stress corrosion cracking was observed both under the microscope and with the naked eye, and the SCC resistance was not sufficient. Furthermore, since the content ratio of S and Mn is small although B is not contained, the diameter reduction rate is 6
It was 3.9%.
【００２６】Ｄ鋼は、Ｓｉの含有割合が０．８０重量％
と本発明の範囲より大きいとともにＢを含有していない
ために、腐食速度の値が大きく耐全面腐食性に劣り、直
径減少率も６０％に達せず熱間加工性が十分でないもの
となった。Ｅ鋼は、Ｓの含有割合が０．００６重量％と
本発明の範囲より大きいとともにＢを含有していないた
めに、直径減少率が６０％に達せず熱間加工性が十分で
ないとともに、顕微鏡観察により応力腐食割れが認めら
れ耐ＳＣＣ性が十分でないものであった。Steel D has a Si content of 0.80% by weight.
Since the content is larger than the range of the present invention and does not contain B, the value of the corrosion rate is large, the general corrosion resistance is poor, the diameter reduction rate does not reach 60%, and the hot workability is insufficient. . Steel E has a S content of 0.006% by weight, which is higher than the range of the present invention, and does not contain B. Therefore, the diameter reduction rate does not reach 60%, the hot workability is not sufficient, and By observation, stress corrosion cracking was recognized and SCC resistance was not sufficient.
【００２７】Ｆ鋼は、Ａｌの含有割合が０．０５７重量
％と本発明の範囲より大きいために降伏強度が９４．８
ｋｓｉと小さく機械的強度に劣るものとなった。また、
顕微鏡観察により応力腐食割れが認められ耐ＳＣＣ性が
十分でないとともに、腐食速度の値が大きく耐全面腐食
性に劣るものであった。さらに、Ｂを含有していないた
めに、直径減少率が６０％に達せず熱間加工性も十分で
ないものとなった。The F steel has a yield strength of 94.8 because the Al content is 0.057% by weight, which is larger than the range of the present invention.
It was as small as ksi and was inferior in mechanical strength. Also,
Under the microscope, stress corrosion cracking was observed, the SCC resistance was not sufficient, and the corrosion rate was large and the general corrosion resistance was poor. Further, since B was not contained, the diameter reduction rate did not reach 60% and the hot workability was not sufficient.
【００２８】Ｇ鋼は、Ｏの含有割合が０．００６重量％
と本発明の範囲より大きいために、腐食速度の値が大き
く耐全面腐食性に劣るとともに、Ｂを含有していないた
めに、直径減少率が６０％に達せず熱間加工性も十分で
ないものとなった。Ｈ〜Ｉ鋼は、Ｃ〜Ｏまでの含有割合
は本発明の範囲に入っているが、Ｂを含有していないた
めに、直径減少率が６０％に達せず熱間加工性が十分で
ないものとなった。The G steel has an O content of 0.006% by weight.
And, since it is larger than the range of the present invention, the value of the corrosion rate is large and the general corrosion resistance is poor, and since B is not contained, the diameter reduction rate cannot reach 60% and the hot workability is not sufficient. Became. In the H to I steels, the content ratios from C to O are within the scope of the present invention, but since they do not contain B, the diameter reduction rate does not reach 60% and the hot workability is not sufficient. Became.
【００２９】Ｊ鋼は、Ｂの含有量が０．０００４重量％
と本発明の範囲より小さいため、直径減少率が６０％に
達せず、熱間加工性を向上させるＢの効果が発揮されて
いない。Ｋ鋼は、Ｂの含有量が０．０１１８重量％と本
発明の範囲より大きいため、顕微鏡観察により応力腐食
割れが認められ耐ＳＣＣ性が十分でないものであった。
また、直径減少率が６０％に達せず熱間加工性も十分で
ないものとなった。J steel has a B content of 0.0004% by weight.
Since it is smaller than the range of the present invention, the diameter reduction rate does not reach 60%, and the effect of B for improving hot workability is not exhibited. K steel had a B content of 0.0118% by weight, which was larger than the range of the present invention, and therefore stress corrosion cracking was observed by microscopic observation, and the SCC resistance was not sufficient.
Further, the diameter reduction rate did not reach 60%, and the hot workability was not sufficient.
【００３０】[0030]
【発明の効果】以上説明したように本発明の油井管用マ
ルテンサイト系ステンレス鋼は、Ｃの含有割合を従来よ
り著しく低減した13Ｃｒ鋼にＮｉ、Ｍｏ、Ｎを添加し、
Ｓ、Ｓｉ、Ａｌ、Ｏの含有割合を低減するとともに、Ｂ
を0.0005〜0.0100重量％の範囲で含有することにより、
ＣＯ2 、Ｈ2 Ｓ、Ｃｌ- を含む厳しい腐食環境下であっ
て温度が100 〜150 ℃となる環境下での耐全面腐食性お
よび耐ＳＣＣ性を損なうことなく、機械的強度も確保し
ながら、熱間加工性を十分に高くすることが可能とな
る。すなわち、本発明の鋼は、油井管用として、前述の
ような苛酷な環境下で使用可能な特性と、製造時の加工
し易さとを兼ね備えているものである。As described above, in the martensitic stainless steel for oil country tubular goods of the present invention, Ni, Mo and N are added to 13Cr steel in which the content ratio of C is remarkably reduced as compared with the conventional case.
While reducing the content ratio of S, Si, Al, and O, B
By containing 0.0005 to 0.0100% by weight,
While maintaining mechanical strength without impairing general corrosion resistance and SCC resistance in a severe corrosive environment containing CO 2 , H 2 S, and Cl − and a temperature of 100 to 150 ° C. Therefore, it becomes possible to sufficiently enhance the hot workability. That is, the steel of the present invention has both the characteristics that can be used under the harsh environment as described above for oil country tubular goods and the ease of processing during manufacturing.
【図１】本発明の実施例における耐ＳＣＣ性を調べるた
めの試験方法（試験片への応力付与状態）を示す正面図
である。FIG. 1 is a front view showing a test method (state in which stress is applied to a test piece) for examining SCC resistance in an example of the present invention.
Ｃ 試験片 Ｇ 曲げ治具 C Test piece G Bending jig
Claims (1)
％以下、Ｍｎ：0.30〜1.20重量％、Ｐ：0.025 重量％以
下、Ｓ：0.005 重量％以下、Ｃｒ：12.0〜14.0重量％、
Ｎｉ：3.0 〜5.0 重量％、Ｍｏ：0.5 〜1.5 重量％、Ａ
ｌ:0.01 〜0.05重量％、Ｎ：0.03〜0.08重量％、Ｏ：0.
005 重量％以下、Ｂ：0.0005〜0.0100重量％を含有し、
残部がＦｅおよび不可避的不純物よりなることを特徴と
する油井管用マルテンサイト系ステンレス鋼。1. C: 0.02 to 0.05% by weight, Si: 0.50% by weight or less, Mn: 0.30 to 1.20% by weight, P: 0.025% by weight or less, S: 0.005% by weight or less, Cr: 12.0 to 14.0% by weight,
Ni: 3.0 to 5.0% by weight, Mo: 0.5 to 1.5% by weight, A
1: 0.01 to 0.05% by weight, N: 0.03 to 0.08% by weight, O: 0.
005% by weight or less, B: 0.0005 to 0.0100% by weight,
A martensitic stainless steel for oil country tubular goods, wherein the balance is Fe and inevitable impurities.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21167493A JPH0762499A (en) | 1993-08-26 | 1993-08-26 | Martensitic stainless steel for oil well pipe |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21167493A JPH0762499A (en) | 1993-08-26 | 1993-08-26 | Martensitic stainless steel for oil well pipe |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0762499A true JPH0762499A (en) | 1995-03-07 |
Family
ID=16609720
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP21167493A Pending JPH0762499A (en) | 1993-08-26 | 1993-08-26 | Martensitic stainless steel for oil well pipe |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0762499A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1996038597A1 (en) * | 1995-05-31 | 1996-12-05 | Dalmine S.P.A. | Martensitic stainless steel having high mechanical strength and corrosion resistance and relative manufactured articles |
| JPH10130787A (en) * | 1996-10-29 | 1998-05-19 | Kawasaki Steel Corp | High strength martensitic stainless steel for oil well pipe, excellent in stress corrosion cracking resistance and high temperature tensile characteristic |
| JP2000313941A (en) * | 1999-04-27 | 2000-11-14 | Nippon Steel Corp | Seamless tube of martensitic stainless steel excellent in surface quality |
| JP2000313942A (en) * | 1999-04-27 | 2000-11-14 | Nippon Steel Corp | Seamless tube of martensitic stainless steel excellent in surface quality |
| CN104451394A (en) * | 2014-11-25 | 2015-03-25 | 江苏常宝钢管股份有限公司 | Anti-CO2 corrosion oil well pipe below 150 ksi produced by CPE unit and production method thereof |
-
1993
- 1993-08-26 JP JP21167493A patent/JPH0762499A/en active Pending
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1996038597A1 (en) * | 1995-05-31 | 1996-12-05 | Dalmine S.P.A. | Martensitic stainless steel having high mechanical strength and corrosion resistance and relative manufactured articles |
| US5944921A (en) * | 1995-05-31 | 1999-08-31 | Dalmine S.P.A. | Martensitic stainless steel having high mechanical strength and corrosion resistance and relative manufactured articles |
| CN1079841C (en) * | 1995-05-31 | 2002-02-27 | 达尔米内股份公司 | Martensitic stainless steel having high mechanical strength and corrosion resistance and relative mfd. articles |
| JPH10130787A (en) * | 1996-10-29 | 1998-05-19 | Kawasaki Steel Corp | High strength martensitic stainless steel for oil well pipe, excellent in stress corrosion cracking resistance and high temperature tensile characteristic |
| JP2000313941A (en) * | 1999-04-27 | 2000-11-14 | Nippon Steel Corp | Seamless tube of martensitic stainless steel excellent in surface quality |
| JP2000313942A (en) * | 1999-04-27 | 2000-11-14 | Nippon Steel Corp | Seamless tube of martensitic stainless steel excellent in surface quality |
| CN104451394A (en) * | 2014-11-25 | 2015-03-25 | 江苏常宝钢管股份有限公司 | Anti-CO2 corrosion oil well pipe below 150 ksi produced by CPE unit and production method thereof |
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