JPS61123496A - Pressure vessel excelient in corrosion resistance and peeling crack resistance due to hydrogen - Google Patents
Pressure vessel excelient in corrosion resistance and peeling crack resistance due to hydrogenInfo
- Publication number
- JPS61123496A JPS61123496A JP24158284A JP24158284A JPS61123496A JP S61123496 A JPS61123496 A JP S61123496A JP 24158284 A JP24158284 A JP 24158284A JP 24158284 A JP24158284 A JP 24158284A JP S61123496 A JPS61123496 A JP S61123496A
- Authority
- JP
- Japan
- Prior art keywords
- hydrogen
- stainless steel
- less
- corrosion resistance
- welding
- 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
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
- B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
- B23K35/24—Selection of soldering or welding materials proper
- B23K35/30—Selection of soldering or welding materials proper with the principal constituent melting at less than 1550 degrees C
- B23K35/3053—Fe as the principal constituent
- B23K35/308—Fe as the principal constituent with Cr as next major constituent
- B23K35/3086—Fe as the principal constituent with Cr as next major constituent containing Ni or Mn
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は１層以上の構造を有する圧力容器に関するもの
であって、特に高温高圧水素雰囲気の環境において耐食
性に優れ、ステｔンレス鋼溶接金属と母材軟鋼または低
合金鋼との境界部で水素剥離割れを起こし難い内層材を
有する圧力容器に係るものである。Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a pressure vessel having a structure of one or more layers, which has excellent corrosion resistance particularly in a high-temperature, high-pressure hydrogen atmosphere environment, and which is suitable for stainless steel welded metal. This relates to a pressure vessel having an inner layer material that does not easily cause hydrogen exfoliation cracking at the boundary between the steel and the base material mild steel or low alloy steel.
従来、炭素鋼および低合金鋼などで製造される石油精製
１重質油分解などの圧力容器や化学反応容器の内面は耐
食性を確保するｔめ、オーステナイト系ステンレス鋼に
よるライニングがなされている。これらのクラツド鋼に
よる圧力容器において、高温重圧水素環境下で使用され
ると、水素侵食による材質劣化が生じ、運転停止による
加熱・冷却の繰返しにより母材とステンレス鋼溶接金属
内層材との境界に沿って、剥離割れが発生することがあ
り問題となっているため、より一層信頼性の高い内層材
の出現が望まれている。BACKGROUND ART Conventionally, the inner surfaces of pressure vessels and chemical reaction vessels for petroleum refining, heavy oil cracking, etc., which are manufactured using carbon steel, low alloy steel, etc., are lined with austenitic stainless steel to ensure corrosion resistance. When pressure vessels made of these clad steels are used in high-temperature, high-pressure hydrogen environments, material deterioration occurs due to hydrogen erosion, and repeated heating and cooling due to shutdowns causes damage to the boundary between the base material and the inner layer of stainless steel weld metal. Since peeling cracks may occur along the line, which is a problem, there is a desire for an even more reliable inner layer material.
この様な剥離割れの防止方法として、特公昭５６−７７
９２号公報に開示されている如く、フェライト系ステン
レス鋼を１層肉盛溶接し、さらにその上に通常のオース
テナイト系ステンレス鋼を肉盛溶接する方法、特公昭５
９−６７４４号公報に開示されている如く、１層目にＳ
ＵＳ ３０９系ステンレス鋼にＭｅを２〜４％添加した
ステンレス鋼を１層肉盛溶接し、２層目に従来のＳＵＳ
３４７系ステンレス鋼を肉盛溶接する方法、特開昭５
４−１０７４５３号公報に示されている如く、Ｎｂを含
有する低合金鋼を１層以上下盛り溶接し、その上に通常
のオーステナイト系又はフェライト系ステンレス鋼を１
層以上内盛溶接する方法等がある。As a method to prevent such peeling cracks,
As disclosed in Japanese Patent Publication No. 92, a method of welding a single layer of ferritic stainless steel and then welding a normal austenitic stainless steel on top of that, Japanese Patent Publication No. 5
As disclosed in Publication No. 9-6744, the first layer is S.
One layer of US 309 series stainless steel with 2 to 4% Me added is overlay welded, and the second layer is conventional SUS.
Method of overlay welding 347 series stainless steel, JP-A-5
As shown in Publication No. 4-107453, one or more layers of Nb-containing low alloy steel are under-welded, and one layer or more of ordinary austenitic or ferritic stainless steel is welded on top.
There are methods such as internal welding of more than one layer.
これらの方法は、水素剥離割れ防止方法として下盛浴接
材料の選定に関するものであり、更に過酷な腐食環境か
ら圧力容器を保饅する念め、耐食性を有するオーステナ
イト系ステンレス鋼等を上盛溶接する工程を避けること
ができない口そのため、溶接工数、検査工数が増すとと
もに、下盛溶接材料と上盛溶接材料が異なるため、溶接
材料の取替え、セツティング作業等の付随作業が必要で
あり、作業が煩雑となり、作業能率が悪くなる。These methods are related to the selection of underlay welding materials as a method to prevent hydrogen exfoliation cracking, and in order to protect the pressure vessel from harsh corrosive environments, overlay welding of corrosion-resistant austenitic stainless steel, etc. As a result, welding man-hours and inspection man-hours increase, and because the bottom welding material and top welding material are different, incidental work such as replacing welding material and setting work is required. becomes complicated and reduces work efficiency.
本発明は、圧力容器内面を肉盛溶接する場合の上述のよ
うな不具合を解消し、１層盛溶接でも、耐食・耐水素剥
離割れ性に優れた圧力容器を提供することを目的とする
。An object of the present invention is to eliminate the above-mentioned problems when performing overlay welding on the inner surface of a pressure vessel, and to provide a pressure vessel that is excellent in corrosion resistance and hydrogen peeling cracking resistance even with single-layer overlay welding.
本発明者等は、炭素鋼および低合鋼外層材とステンレス
鋼内層材の境界部に発生する水素剥離割れの問題点を解
決すべく、剥離割れに対する要因の調査およびステンレ
ス鋼内層材の合金成分系について検討を行う念。圧力容
器の製造は操某条件が苛酷になるにつれ外層材の板厚が
厚くなり、クラッド法としては肉盛溶接が主として用い
られるため、クラツド鋼の製作工程上、クラッド部につ
いて固溶化熱処理が自由に行えないばかりでなく、６０
０〜７５０℃で２０〜５０時間に及ぶ炭素鋼または低合
金鋼側の応力除去熱処理の影響を受は炭化物の析出やシ
グマ相の生成が促進される。まｔ１内層材と外層材との
境界部においては、炭素鋼または低合金鋼側からステン
レス鋼へのＣの拡散が行なわれる結果、炭化物が形成さ
れ、耐食性および（幾械的性質が低下するとともに、水
素のトラップサイトとなり水素感受性が高くなる。ま之
、圧力容器外層材（フェライト）とオーステナイトステ
ンレス鋼内層材との熱膨張係数の差が大きいため、加熱
・冷却の繰返しにより、境界部における歪、残留応力が
発生する。さらに、圧力容器外層材（フェライト）とオ
ーステナイト、ステンレス鋼内層材の水素溶解度の不連
続性が低温になるほど激しくなり、圧力容器の運転停止
時には残留水素の過飽和度の差が大きくなるため、境界
部へ水素が拡散集積すること等が主原因となり、水素剥
離割れが発生することが明らかとなった。In order to solve the problem of hydrogen peeling cracks that occur at the boundary between carbon steel and low alloy steel outer layer materials and stainless steel inner layer materials, the present inventors investigated the factors that cause peeling cracks and investigated the alloy composition of stainless steel inner layer materials. I intend to consider the system. In the manufacture of pressure vessels, as the operating conditions become more severe, the thickness of the outer layer material becomes thicker, and overlay welding is mainly used as the cladding method. Therefore, solution heat treatment of the cladding part is free in the manufacturing process of clad steel. Not only can you not go to 60
Under the influence of stress relief heat treatment on the carbon steel or low alloy steel side at 0 to 750°C for 20 to 50 hours, precipitation of carbides and generation of sigma phase are promoted. At the boundary between the inner layer material and the outer layer material, carbide is formed as a result of diffusion of C from the carbon steel or low alloy steel side into the stainless steel, resulting in a decrease in corrosion resistance and mechanical properties. , which becomes a trap site for hydrogen and increases hydrogen sensitivity.However, due to the large difference in thermal expansion coefficient between the pressure vessel outer layer material (ferrite) and the austenitic stainless steel inner layer material, repeated heating and cooling can cause strain at the boundary. , residual stress occurs.Furthermore, the discontinuity in hydrogen solubility between the pressure vessel outer layer material (ferrite) and the austenite and stainless steel inner layer materials becomes more severe as the temperature decreases, and the difference in the supersaturation degree of residual hydrogen occurs when the pressure vessel is stopped. It has become clear that hydrogen diffusion and accumulation at the boundary is the main cause of hydrogen exfoliation cracking due to the increase in hydrogen.
そこで、炭素鋼およびステンレス鋼溶接金属の１λ界部
の水素剥離Ｍれの発生原因を明確にするとともに防止方
法について研究を進めてきたところ、炭素鋼または低合
金鋼外層材とステンレス鋼内層材の境界部に炭化物が形
成され、組織的に不連続性が生じても、水素が存在しな
ければ剥離割れが発生しないことが明らかとなっ念。そ
こで水素の境界部への拡散業績に及ぼす肉盛溶接金属内
層材の組織の影響について研究を進めた結果、溶接金属
の組織が大きな影＃を及ぼしていることを見出した。一
般のオーステナイト系ステンレス鋼の溶接に際しては熱
間割れを防止するため数多のフェライトを含む組織とす
ることが通常であるが、オーステナイト系ステンレス鋼
の溶接金属では、水素の拡散係数は炭素鋼または低合金
鋼外層材と溶接金属内層材との差が大きく、水素の境界
部への拡散集積が増大するため、剥離割れが発生する。Therefore, we have clarified the cause of hydrogen peeling M at the 1λ interface of carbon steel and stainless steel weld metals and have been conducting research on prevention methods. It has become clear that even if carbides are formed at the boundary and structural discontinuity occurs, exfoliation cracks will not occur in the absence of hydrogen. Therefore, as a result of researching the influence of the structure of the inner layer material of the overlay weld metal on the performance of hydrogen diffusion into the boundary area, we discovered that the structure of the weld metal has a large influence. When welding general austenitic stainless steel, it is normal to create a structure that contains many ferrites to prevent hot cracking, but in the weld metal of austenitic stainless steel, the hydrogen diffusion coefficient is lower than that of carbon steel. There is a large difference between the low alloy steel outer layer material and the weld metal inner layer material, and the diffusion and accumulation of hydrogen at the boundary increases, resulting in peeling cracks.
しかし、ｖ６接金属内層材のＮｉｅｑおよびＣｒ ｅｑ
を適当に調整し、フェライトを含んだ２相系オーステナ
イトステンレス鋼の浴接金属とすることにより、水素剥
離割れに対する抵抗性が著しく向上することか確かめら
れた。即ち、フェライト鋼における水素の拡散係数はオ
ーステナイト鋼より常温において１０３〜１０４倍と著
しく大きく、水素の拡散速度が非常に運やく、また水素
の溶解度が数倍率さいことは一般に知られていることで
あるが、フェライト組織を適量含む２相系オーステナイ
トステンレス鋼では、上記物理的性質がフェライトｊＩ
ｉ相ステンレス鋼と同等の（Ｌｎｔ−示すことが分った
。そこで、適量のフェライト組織を含む２相系オーステ
ナイト・ステンレス鋼溶接金属の試験片について、耐水
素剥離割れ性を調査した結果、オーステナイト・ステン
レス鋼の場合より耐剥離割れ性が著しく向上することが
明らかとなった。このことはフェライト組織を優先径路
として水素が拡散し、溶接金属表面から放出され、この
剥離割れの主原因である境界部への水素の拡散集積が防
止されるためと考えられる。また、適量のフェライトを
含むオーステナイトステンレス鋼溶接金属の延性。However, Nieq and Cr eq of v6 metal inner layer material
It was confirmed that resistance to hydrogen exfoliation cracking can be significantly improved by appropriately adjusting the ferrite-containing two-phase austenitic stainless steel as a bath welding metal. In other words, it is generally known that the hydrogen diffusion coefficient in ferritic steel is 103 to 104 times greater than that in austenitic steel at room temperature, that the diffusion rate of hydrogen is extremely high, and that the solubility of hydrogen is several times lower. However, in two-phase austenitic stainless steel containing a suitable amount of ferrite structure, the above physical properties are similar to those of ferrite jI.
It was found that the hydrogen exfoliation cracking resistance of test pieces of two-phase austenitic stainless steel weld metal containing an appropriate amount of ferrite structure was investigated.・It was revealed that the exfoliation cracking resistance was significantly improved compared to stainless steel.This means that hydrogen diffuses through the ferrite structure as a preferential path and is released from the weld metal surface, which is the main cause of this exfoliation cracking. This is thought to be due to the prevention of diffusion and accumulation of hydrogen at the boundary.Also, the ductility of austenitic stainless steel weld metal containing a suitable amount of ferrite.
耐食性について、調査した結果、水素吸収による延性低
下に対しても良好な結果を示し、耐食性に関してはＳ量
を抑制することにより、特に耐孔食性を改善できること
が明らかとなった。As for corrosion resistance, as a result of investigation, it was found that good results were shown even against the decrease in ductility due to hydrogen absorption, and that pitting corrosion resistance in particular can be improved by suppressing the amount of S.
本発明は前述の知見に基すいてなされたものであって、
１層目溶接金属組成を改良することにより、下盛溶接工
程を省くことができ、圧力容器製造時の工程数を低減し
、作業能率を高め、かつ所期の諸性能を有する溶接金属
を得ることができる。The present invention was made based on the above-mentioned findings, and
By improving the composition of the first layer weld metal, it is possible to omit the underlay welding process, reduce the number of steps during pressure vessel manufacturing, improve work efficiency, and obtain a weld metal that has the desired performance. be able to.
本発明の目的は、熱間割れを生ぜず、かつ高温高圧水素
雰囲気の環境ておいて、耐食性および耐水素剥離割れ性
の優れ念内層材を有する溶接構造の圧力容器を提供する
にある。An object of the present invention is to provide a pressure vessel of welded structure that does not cause hot cracking and has an inner layer material that exhibits excellent corrosion resistance and hydrogen peeling cracking resistance in a high-temperature, high-pressure hydrogen atmosphere environment.
本発明の要旨は、炭素鋼または低合金鋼を外層材とし、
フェライト組織を含む２相系オーステナイト・ステンレ
ス鋼の１層以上を内層材とする高温高圧水素雰囲気で使
用される圧力容器において、該ステンレス鋼部の１層目
溶接金種の化学成分が重”ａｓでＮｉが６．０〜１２．
０％、 Ｃｒが１８．０〜２８．０％、 Ｍｎが１゜０
〜２．０チであり、さらにＣが０．６％以下、 ｓｔが
０．８％以下、 Ｍｏが２，５チ以下、 Ｎｂが０、９
％以下、Ｓが０．０１０％以下、残部は鉄及び不可避不
純物からなり、かつその化学成分のＮｉ ｅｑ ＝Ｎｉ
＋３０ Ｃ＋０．５ ＭｎＣｒ ｅｑ ＝ Ｃｒ ＋
ＭＯ＋ １゜５ Ｓｔ ＋０．５ Ｎｂから計算した
Ｃｒ ｅｑの値が
２２≦Ｃｒ ｅｑ≦３０
かつ・
１゜５ Ｎｉ ｅｑ ＋ ８．５≦Ｃｒ ｅｑ≦１．７
Ｎｉ ｓｑ＋９．３の関係を満足し、シェフラー状態図
においてフェライト＋オーステナイト２相域にある組成
を有することを特徴とする耐食・耐水素剥離割れ特性に
優れた圧力容器にある。The gist of the present invention is to use carbon steel or low alloy steel as the outer layer material,
In a pressure vessel used in a high-temperature, high-pressure hydrogen atmosphere in which the inner layer is one or more layers of two-phase austenitic stainless steel containing a ferritic structure, the chemical composition of the first layer welding metal of the stainless steel part is heavy "as". and Ni is 6.0 to 12.
0%, Cr 18.0-28.0%, Mn 1゜0
~2.0chi, and furthermore, C is 0.6% or less, st is 0.8% or less, Mo is 2.5 or less, and Nb is 0.9%.
% or less, S is 0.010% or less, the balance consists of iron and unavoidable impurities, and its chemical components Ni eq = Ni
+30 C+0.5 MnCr eq = Cr +
MO+ 1゜5 St +0.5 The value of Cr eq calculated from Nb is 22≦Cr eq≦30 and 1゜5 Ni eq + 8.5≦Cr eq≦1.7
The pressure vessel satisfies the relationship of Ni sq + 9.3 and has a composition in the ferrite + austenite two-phase region in the Schaeffler phase diagram, and has excellent corrosion resistance and hydrogen exfoliation cracking resistance.
以下に本発明の詳細な説明する。The present invention will be explained in detail below.
まず、本発明圧力容器内層のステンレス鋼クラッド部に
ついて、各化学成分範囲を前記のごとく定めた理由につ
いて記述する。First, the reason why each chemical component range was determined as described above for the stainless steel cladding part of the inner layer of the pressure vessel of the present invention will be described.
Ｎｉはフェライト・オーステナイト２相系ステンレス鋼
の基本元素であり、オーステナイトを安定化さすために
は６．０％以上は必要である。Ｎｌの増加は靭性及び耐
応カ腐食性割れ性を向上させるが、多すぎると溶接時の
熱間割れの問題があり、１２．０−以下とした。Ni is a basic element of ferrite-austenite dual phase stainless steel, and 6.0% or more is required to stabilize austenite. An increase in Nl improves toughness and stress corrosion cracking resistance, but if it is too large, there is a problem of hot cracking during welding, so it is set to 12.0 or less.
Ｃｒはステンレス鋼の基本成分であり、１２．０％から
耐食性がでてきて耐孔食性などに優れた性質を示すには
２０．０１以上が必要である。Ｃｒは多い程耐食性を向
上させるが、フェライトを多量に形成し、後熱処理に伴
ないシグマ相を析出し脆化の問題が生じるため２８．０
％以下とした。Cr is a basic component of stainless steel, and corrosion resistance starts from 12.0%, and a content of 20.01 or more is required to exhibit excellent properties such as pitting corrosion resistance. The more Cr, the better the corrosion resistance, but it forms a large amount of ferrite and precipitates a sigma phase during post-heat treatment, causing the problem of embrittlement.
% or less.
Ｍｎはクラッド素材製造に際し、熱間加工性を向上させ
、クラッド部の強度を増加させるばかりでなく、クラッ
ド部の接合溶接に際して溶接金属中のＳと結合して溶接
時の熱間割れ感受性を低めるうえで１．０％以上含有す
ると効果があるが、これを多量に含有することは応力腐
食割れ感受性を高め、かつクラッド部の材質を劣化させ
るため、含有Ｍｎ量は１．０〜２．０チとした。When manufacturing cladding materials, Mn not only improves hot workability and increases the strength of the cladding part, but also combines with S in the weld metal when welding the cladding part to reduce hot cracking susceptibility during welding. It is effective to contain 1.0% or more of Mn, but since containing a large amount of Mn increases the susceptibility to stress corrosion cracking and deteriorates the material of the cladding, the amount of Mn contained is 1.0 to 2.0%. It was hot.
Ｃは熱処理により粒界にクロム炭化物を排出させＣｒ欠
之による粒界腐食の原因となるので０．０６−以下とし
た。C is set to 0.06 or less because it causes chromium carbide to be discharged to grain boundaries during heat treatment and causes intergranular corrosion due to Cr deficiency.
Ｓｌは強力な脱酸剤ではあるが靭性の低下、熱間割れの
問題などから０．８％以下が好ましい。Although Sl is a strong deoxidizing agent, it is preferably 0.8% or less due to problems such as deterioration of toughness and hot cracking.
Ｍｏは耐孔食性に優れた元素であり、高温強度を高める
のに役立つが、２．５％超では６５０℃以上の熱処理で
脆化し衝撃値が低下する。Mo is an element with excellent pitting corrosion resistance and is useful for increasing high-temperature strength, but if it exceeds 2.5%, it becomes brittle when heat treated at 650° C. or higher and the impact value decreases.
Ｎｂ ｔｌ Ｃを固定し耐粒界腐食性を改善する元素で
ある。しかし、Ｃの重量％で８〜１０倍以上でかつ１．
０％超のＮｂの添加は溶接に際して熱間割れ感受性を高
める。It is an element that fixes Nb tl C and improves intergranular corrosion resistance. However, the weight percentage of C is 8 to 10 times or more and 1.
Addition of more than 0% Nb increases hot cracking susceptibility during welding.
Ｓは溶接金属の凝固の際、粒界に低融点の共晶を形成し
、熱間割れ感受性を高めるだけで、耐孔食性を低めるの
でｏ、ｏｔｏｓ以下とした。S forms a low-melting-point eutectic at grain boundaries during solidification of the weld metal, which only increases hot cracking susceptibility and reduces pitting corrosion resistance, so it was set to be less than o, otos.
上記以外の化学成分については通常のステンレス鋼と同
様なものでよいが、その化学成分がＮｉ ｅｑ−Ｎｉ＋
３０Ｃ＋０．５Ｍｎ、Ｃｒ ＠ｑ＝Ｃｒ＋１．５Ｓｉ＋
０．５ Ｎｂ ＋ Ｍｏから計算したＣｒ ｅｑの値
が２２≦Ｃｒ ｅｑ≦３０ ・（１）１．５Ｎｉ
ｅｑ＋８．５≦Ｃｒ ｅｑ≦１．７Ｎｉ＠ｑ＋９゜３
・・・（ＩＩ）
の（１） 、 （ｎ）式を満足し、シェフラー状態図に
おいてフェライト＋オーステナイト２相域にあることを
必須とする。この式を満足するＣｒ ＠ｑ、 Ｎｉ ｅ
ｑ値が第１図に示すシェフラー状態図においてフェライ
ト＋オーステナイト２相域にある場合、耐食性及び機械
的性質が良好で、かつ使用時の高温高圧の水素環境など
によって生じる水素脆化ならびに運転停止時に発生する
水素剥離割れを防ぐことになる。The chemical components other than those listed above may be the same as those of ordinary stainless steel, but the chemical components are Ni eq-Ni+
30C+0.5Mn, Cr @q=Cr+1.5Si+
The value of Cr eq calculated from 0.5 Nb + Mo is 22≦Cr eq≦30 ・(1) 1.5Ni
eq+8.5≦Cr eq≦1.7Ni@q+9゜3
...(II) Equations (1) and (n) must be satisfied, and it must be in the ferrite + austenite two-phase region in the Schaeffler phase diagram. Cr @q, Ni e that satisfies this formula
If the q value is in the ferrite + austenite two-phase region in the Schaeffler phase diagram shown in Figure 1, corrosion resistance and mechanical properties are good, and hydrogen embrittlement caused by high-temperature, high-pressure hydrogen environments during use, etc. This will prevent hydrogen peeling cracks from occurring.
ここで第１図におけるフェライト＋オーステナイト２相
域とは同図に示すように、Ｃｒ＊ｑかフェライトｔ３０
％の線（Ｃｒ ＠ｑ＝１．５Ｎｉ ＠ｑ＋８．５ ）よ
り大きく、フェライト量５０チの線（Ｃｒ ｅｑ ｘｌ
、７Ｎｌ ｅｑ＋９．３ ）より小さく、かつＣｒ ｅ
ｑが２２〜３０の範囲がこれに該当するものである。Ｃ
ｒ ＠（１が小さいと靭性、耐食性が低下し１．大きす
ぎると後熱処理に伴ないシグマ相が析出し、耐食性およ
び耐衝撃性が低下するのでＣｒ ｅｑの範囲を２２〜３
０に規定した。Here, the ferrite + austenite two-phase region in Fig. 1 means Cr*q or ferrite t30, as shown in the same figure.
% line (Cr @q=1.5Ni @q+8.5), and the line with ferrite amount of 50 cm (Cr eq xl
, 7Nl eq+9.3), and Cre
The range of q from 22 to 30 corresponds to this. C
r @ (If 1 is small, toughness and corrosion resistance will decrease. If it is too large, sigma phase will precipitate during post-heat treatment and corrosion resistance and impact resistance will decrease, so the range of Cr eq is 22 to 3.
It was set to 0.
まｔここでいう２相系ステンレス鋼とはＮｉが６．０〜
１２．０％、 Ｃｒが１８．０〜２８．０ ％ 、 Ｍ
ｎが１．０〜２．０％、Ｃが０．０６％以下、 ８１が
０．８−以下、 Ｍｏが２．５％以下、 Ｎｂが１．０
％以下、Ｓが０．０１０チ以下のものをいう。この場合
、微量のＡｔ、Ｔｉ。The duplex stainless steel mentioned here has a Ni content of 6.0~
12.0%, Cr 18.0-28.0%, M
n is 1.0-2.0%, C is 0.06% or less, 81 is 0.8- or less, Mo is 2.5% or less, Nb is 1.0
% or less, S is 0.010 inch or less. In this case, trace amounts of At and Ti.
Ｃａ 、Ｖなどが含まれることがある。その他年可避不
純物としてＰ 、 Ｃｕなどがあるが、これらの成分は
肉盛溶接時の割れ感受性を高めるため極めて少ないこと
が好ましい。Ca, V, etc. may be included. Other unavoidable impurities include P, Cu, etc., but it is preferable that these components be extremely small in order to increase the sensitivity to cracking during overlay welding.
この様な１層以上の内層材からなる構造を有する圧力容
器の素材を得る方法としては炭素鋼または低合金鋼と前
述の化学成分範囲を満足するフェライト＋オーステナイ
ト２相系ステンレス鋼とを組合せて圧延または爆発圧接
などにより貼り合わせる方法及び肉盛溶接による方法が
ある。また、肉盛溶接の方法としては被覆アーク溶接、
潜弧溶接、 ＴＩＧ溶接、 ＭＩＧ溶接、エレクトロス
ラグ溶接及びがス洛接などの溶接法を用いることができ
る。A method of obtaining a pressure vessel material having a structure consisting of one or more inner layer materials is to combine carbon steel or low alloy steel with ferritic + austenitic dual phase stainless steel that satisfies the above chemical composition range. There are a method of pasting together by rolling or explosive welding, and a method of overlay welding. In addition, the overlay welding methods include shielded arc welding,
Welding methods such as submerged arc welding, TIG welding, MIG welding, electroslag welding, and gas welding can be used.
これらの各種溶接法によりクラツド鋼の内層材を得る場
合にはそれぞれの溶接方法での母材に対する稀釈率（一
般には５〜４０％）、組合せるフラックス剤またはガス
組成に変化する合金成分の歩留りを考池して電極材の成
分を決定すべきである。また、肉盛浴接法にてクラッド
部材を得る場合には稀釈率の小さい溶接施工法を採るべ
きであり、単層ま念は多層の肉盛部において各層の肉感
溶接金属が本発明の化学成分範囲を満足することが好ま
しいが、１層目のみ満足する場合においても本発明の目
的を十分満足する。When obtaining the inner layer material of clad steel by these various welding methods, the dilution ratio (generally 5 to 40%) of the base material of each welding method, the flux agent to be combined or the yield of alloy components that change to the gas composition The composition of the electrode material should be determined by considering the following. In addition, when obtaining a cladding member using the overlay bath welding method, a welding method with a small dilution rate should be adopted. Although it is preferable that the component ranges are satisfied, even if only the first layer is satisfied, the object of the present invention is fully satisfied.
以下、本発明の効果を実施例により更に具体的に説明す
る。Hereinafter, the effects of the present invention will be explained in more detail with reference to Examples.
外層材の低合金鋼については５Ｂ４６とＡ３８７−２２
を使用し、ステンレス鋼の内層材としては第１表に示す
溶接金属が得られるよう０．４Ｘ７５■断面形状を有す
る第２表に示す帯状電極と第３表に示す潜弧フラックス
とを組合せ、て直流定電圧の溶接機にて逆極性で１２０
ＯＡ、２５Ｖ 、１８ｃ！Ｖ／ｍｉｎの溶接条件にて１
層盛溶接を行った。得られた各種肉盛溶接鋼について、
６９０℃で２１時間の溶接後熱処理後、側曲げ試験、ス
トラウス粒界１に食試験、５％Ｈ２ＳＯ４＋ ３ Ｔｏ
ＮａＣ２中での分極測定［ｊる孔食電位測定を行った
・
史に溶接後熱処理後の肉盛祷接鋼について、耐水素剥に
割れ性を求めるため、幅４５．長さ７０゜高さ４０ｍの
剥離割れ試験片に加工し、実績に供した。水素剥離割れ
試験は水素分圧２００ ｋｇｆ／ＣｌｌＩ２゜温度４５
０℃のオートクレーブ中に試販片を装入し、４８時間保
持した後、大気中に販出し、呈温まで空冷した。水素剥
離割れ発生の有無は超音波ホログラフィ（ＵＳＴ）で調
査した。これらの試験結果を第４表に示す。5B46 and A387-22 for low alloy steel for outer layer material
As the inner layer material of stainless steel, a strip electrode shown in Table 2 having a cross-sectional shape of 0.4 x 75 mm was combined with a submerged arc flux shown in Table 3 to obtain the weld metal shown in Table 1. 120 with reverse polarity using a DC constant voltage welding machine.
OA, 25V, 18c! 1 under welding conditions of V/min
Layer welding was performed. Regarding the various overlay welded steels obtained,
After post-weld heat treatment at 690°C for 21 hours, side bending test, Strauss grain boundary 1 corrosion test, 5% H2SO4+ 3 To
Polarization measurement in NaC2 [j] Pitting corrosion potential measurement was performed in order to determine the cracking resistance of hydrogen peeling of overlay welded steel after post-weld heat treatment. It was processed into a peel crack test piece with a length of 70° and a height of 40 m, and was used for actual testing. Hydrogen exfoliation cracking test was performed at hydrogen partial pressure 200 kgf/CllI2° temperature 45
The sample pieces were placed in an autoclave at 0°C and held for 48 hours, then released into the atmosphere and air-cooled to room temperature. The presence or absence of hydrogen exfoliation cracking was investigated using ultrasonic holography (UST). The results of these tests are shown in Table 4.
第１表に示し之溶接金属について各試料点のもののＮｌ
ｓｑとＣｒ ａｑとをそれぞれ計算し、シェフラー状
態図において第４表に示す耐剥離割れ性の関係で整理す
ると第１図の関係が得られる。同図から明らかな様にＣ
ｒ ＠（ｌがフェライ）［３（ｌの１ｆ３．（Ｃｒ ＠
ｑ−１，４Ｎｉ ＠ｑ＋９．３ ）より小さい場合には
１剥離割れが発生し、それを超えると発生せず、これら
の傾向は極めて明らかである。フェライト量が剥離割れ
の有無を決定する重要な因子となっていることが明白で
ある。即ち第１表における実施例屋１〜１１は上記条件
を満足する例であり、耐水素剥漸割れ性はもとより、曲
げ延性及び耐食性に調蟹することが必要である。Nl of each sample point for the weld metal shown in Table 1
If sq and Cr aq are respectively calculated and arranged according to the relationship of peel cracking resistance shown in Table 4 in the Schaeffler phase diagram, the relationship shown in FIG. 1 is obtained. As is clear from the figure, C
r @ (l is Ferai) [3 (l's 1f3. (Cr @
If it is smaller than q-1,4Ni@q+9.3), 1 peel crack will occur, and if it exceeds it, it will not occur, and these trends are very clear. It is clear that the amount of ferrite is an important factor in determining the presence or absence of exfoliation cracks. That is, Examples 1 to 11 in Table 1 are examples that satisfy the above conditions, and it is necessary to check not only hydrogen peeling cracking resistance but also bending ductility and corrosion resistance.
も全て良好で、健全な肉盛溶接金属が得られている。し
かし、Ｃｒ・ｑがフェライト量３０％の縁（Ｃｒ ＠ｑ
＝ １．５ Ｎｉ ＠ｑ ＋８．５ ）以下の比較例
４１２〜１４は何れも水素剥離割れが発生し本発明の目
的を達成できない。比較例ム１５，１６はＣｒ ＠（ｌ
がフェライト量５０％の線（Ｃｒ ＠ｑｍ１．７Ｎｉ
ｅｑ＋９．３）を超えた場合であるが、水素剥離割れは
発生しないが、後熱処理に伴ない、シグマ相が析出し曲
げ延性、耐食性が低下する。また、比較例４１７〜２１
はＣｒ ＠（１が２２〜３０の範囲を外れ邂場合の比較
例であるが、２２未満の場合は耐食性が之しく、３０を
超えた場合は、耐食性が悪くなるとともに後熱処理によ
りシグマ相が析出し、曲げ延性の劣化をも九らし、耐水
素剥離性以前の問題であり、本発明の目的を達成できな
い。All were in good condition, and sound overlay weld metal was obtained. However, at the edge where Cr・q has a ferrite content of 30% (Cr@q
= 1.5 Ni@q +8.5) In all of Comparative Examples 412 to 14 below, hydrogen peeling cracking occurred and the object of the present invention could not be achieved. Comparative examples 15 and 16 are Cr@(l
is the line with 50% ferrite content (Cr @qm1.7Ni
eq+9.3), hydrogen exfoliation cracking does not occur, but sigma phase precipitates with post-heat treatment, resulting in decreased bending ductility and corrosion resistance. In addition, Comparative Examples 417 to 21
is a comparative example where Cr@(1 is out of the range of 22 to 30. If it is less than 22, the corrosion resistance will be poor, and if it exceeds 30, the corrosion resistance will be poor and the sigma phase will be removed by post-heat treatment. Precipitation and deterioration of bending ductility are also minimized, which is a problem even worse than hydrogen peeling resistance, and the object of the present invention cannot be achieved.
これらの結果からも明白表通り、１肩車溶接でも、耐食
性及び曲げ延性の良好な肉感溶接金属を得ると共に浴接
金属の剥離割れを防止子るためには、肉盛溶接金属をＣ
ｒ・ｑが（Ｉ） 、 Ｑ［）式を満足するフェライト＋
オーステナイト２相系ステンレス鋼〔発明の効果〕
以上の通り本発明に係る２相系ステンレス鋼を内層材と
する圧力容器は高温高圧水素環境下で剥離割れが発生せ
ず、１層成溶接でも良好な耐食性及び曲げ延性を有し、
工数、コスト低減が図られ、１菜的にも実用性が高い。As is clear from these results, in order to obtain a textured weld metal with good corrosion resistance and bending ductility even in single-shoulder welding, and to prevent peeling cracks in the bath weld metal, it is necessary to
Ferrite + where r and q satisfy the formula (I) and Q[)
Austenitic duplex stainless steel [Effects of the invention] As described above, the pressure vessel using the duplex stainless steel according to the present invention as an inner layer material does not cause peeling cracks in a high temperature, high pressure hydrogen environment, and can be welded in a single layer. It has excellent corrosion resistance and bending ductility,
It reduces man-hours and costs, and is highly practical as a single dish.
しかして、この技術を高温高圧水素雰囲気で使用する圧
力容器に適用することにより、肉盛溶接金属の剥離を防
止する方法として有為なものである。Therefore, by applying this technique to a pressure vessel used in a high-temperature, high-pressure hydrogen atmosphere, it is effective as a method for preventing peeling of overlay weld metal.
第１図はシェフラー状態図における１層目溶接金属の組
織と水素剥離割れとの関係を示す図である。FIG. 1 is a diagram showing the relationship between the structure of the first layer weld metal and hydrogen exfoliation cracking in the Schaeffler phase diagram.
Claims (1)
含む２相系オーステナイト・ステンレス鋼の１層以上を
内層材とする高温高圧水素雰囲気で使用される圧力容器
において、該ステンレス鋼部の１層目溶接金属の化学成
分が重量％でＮｉが６．０〜１２．０％、Ｃｒが２０．
０〜２８．０％、Ｍｎが１．０〜２．０％であり、さら
にＣが０．０６％下、Ｓｉが０．８％以下、Ｍｏが２．
５％以下、Ｎｂが１．０％以下、Ｓが０．０１０％以下
、残部は鉄及び不可避不純物からなり、かつ、その化学
成分の Ｎｉｅｑ＝Ｎｉ＋３０Ｃ＋０．５Ｍｎ Ｃｒｅｑ＝Ｃｒ＋Ｍｏ＋１．５Ｓｉ＋０．５Ｎｂから計
算したＣｒｅｑの値が ２２≦Ｃｒｅｑ≦３０ かつ １．５Ｎｉｅｑ＋８．５≦Ｃｒｅｑ≦１．７Ｎｉｅｑ＋
９．３の関係を満足し、シェフラー状態図においてフェ
ライト＋オーステナイト２相域にある組成を有すること
を特徴とする耐食・耐水素剥離割れ特性に優れた圧力容
器。[Claims] A pressure vessel used in a high-temperature, high-pressure hydrogen atmosphere, in which the outer layer is made of carbon steel or low-alloy steel and the inner layer is made of one or more layers of duplex austenitic stainless steel containing a ferritic structure. The chemical composition of the first layer weld metal of the stainless steel part is 6.0 to 12.0% Ni and 20.0% Cr by weight.
0 to 28.0%, Mn is 1.0 to 2.0%, C is 0.06% or less, Si is 0.8% or less, and Mo is 2.0% or less.
5% or less, Nb is 1.0% or less, S is 0.010% or less, the remainder consists of iron and unavoidable impurities, and calculated from the chemical components Nieq = Ni + 30C + 0.5Mn Creq = Cr + Mo + 1.5Si + 0.5Nb The value of Creq is 22≦Creq≦30 and 1.5Nieq+8.5≦Creq≦1.7Nieq+
9.3, and has a composition in the ferrite + austenite two-phase region in the Schaeffler phase diagram, and has excellent corrosion resistance and hydrogen exfoliation cracking resistance.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP24158284A JPH0630831B2 (en) | 1984-11-17 | 1984-11-17 | Pressure vessel with excellent corrosion resistance and hydrogen delamination cracking resistance |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP24158284A JPH0630831B2 (en) | 1984-11-17 | 1984-11-17 | Pressure vessel with excellent corrosion resistance and hydrogen delamination cracking resistance |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS61123496A true JPS61123496A (en) | 1986-06-11 |
| JPH0630831B2 JPH0630831B2 (en) | 1994-04-27 |
Family
ID=17076454
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP24158284A Expired - Lifetime JPH0630831B2 (en) | 1984-11-17 | 1984-11-17 | Pressure vessel with excellent corrosion resistance and hydrogen delamination cracking resistance |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0630831B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102014101972A1 (en) | 2014-02-17 | 2015-08-20 | Thyssenkrupp Steel Europe Ag | Method for producing a seamless pressure vessel for storing hydrogen |
| WO2016143509A1 (en) * | 2015-03-10 | 2016-09-15 | 株式会社神戸製鋼所 | Build-up welding metal and mechanical structure |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105506499B (en) * | 2014-09-25 | 2018-11-02 | 宝钢不锈钢有限公司 | A kind of ferritic stainless steel and its manufacturing method with good bending appearance |
-
1984
- 1984-11-17 JP JP24158284A patent/JPH0630831B2/en not_active Expired - Lifetime
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102014101972A1 (en) | 2014-02-17 | 2015-08-20 | Thyssenkrupp Steel Europe Ag | Method for producing a seamless pressure vessel for storing hydrogen |
| US9889491B2 (en) | 2014-02-17 | 2018-02-13 | Thyssenkrupp Steel Europe Ag | Method for producing a seamless pressure vessel for storing hydrogen |
| DE102014101972B4 (en) | 2014-02-17 | 2018-06-07 | Thyssenkrupp Steel Europe Ag | Method for producing a seamless pressure vessel for storing hydrogen |
| WO2016143509A1 (en) * | 2015-03-10 | 2016-09-15 | 株式会社神戸製鋼所 | Build-up welding metal and mechanical structure |
| JP2016165750A (en) * | 2015-03-10 | 2016-09-15 | 株式会社神戸製鋼所 | Build-up welding metal and machine structure |
| CN107405732A (en) * | 2015-03-10 | 2017-11-28 | 株式会社神户制钢所 | Deposited metal and mechanical structure thing |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0630831B2 (en) | 1994-04-27 |
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