JPH08281440A - Method for welding socket - Google Patents

Method for welding socket

Info

Publication number
JPH08281440A
JPH08281440A JP7110261A JP11026195A JPH08281440A JP H08281440 A JPH08281440 A JP H08281440A JP 7110261 A JP7110261 A JP 7110261A JP 11026195 A JP11026195 A JP 11026195A JP H08281440 A JPH08281440 A JP H08281440A
Authority
JP
Japan
Prior art keywords
metal
pipe
pipes
carbon steel
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.)
Pending
Application number
JP7110261A
Other languages
Japanese (ja)
Inventor
Yoshinao Urayama
義直 浦山
Jiro Kuniya
治郎 国谷
Masahiro Kobayashi
正宏 小林
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hitachi Ltd
Original Assignee
Hitachi Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Hitachi Ltd filed Critical Hitachi Ltd
Priority to JP7110261A priority Critical patent/JPH08281440A/en
Publication of JPH08281440A publication Critical patent/JPH08281440A/en
Pending legal-status Critical Current

Links

Classifications

    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E30/00—Energy generation of nuclear origin
    • Y02E30/30—Nuclear fission reactors

Landscapes

  • Butt Welding And Welding Of Specific Article (AREA)
  • Arc Welding In General (AREA)

Abstract

PURPOSE: To prevent corrosion and crack of a connecting part of piping with a large quantity of water flowing in atomic reactor, etc. CONSTITUTION: At the time of connecting the metallic tubes of the same composition, a metal having higher corrosive electric potential by 50-300mV (vs. SHE) than that of a metallic material constituting the metallic tube at near the connecting part of the metallic tube is arranged. By this method, the connecting part of the piping having high reliability over a long time of use is obtd.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【産業上の利用分野】本発明は金属管の接続方法に係
り、特に原子力プラントなどの大量の高温水を使用する
プラントの配管の接続部において、長期の使用にわたっ
て、割れ，腐食などの発生しない高信頼性の接続部を有
する接続方法、それに用いる金属管、及びその方法によ
り接続された接続部を有するプラントの配管に関するも
のである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of connecting metal pipes, and particularly to a pipe connecting portion of a plant using a large amount of high temperature water such as a nuclear power plant, which is free from cracks and corrosion over a long period of use. The present invention relates to a connecting method having a highly reliable connecting portion, a metal pipe used for the connecting method, and a plant pipe having a connecting portion connected by the method.

【０００２】[0002]

【従来の技術】沸騰水型原子炉（以下ＢＷＲと称する）
の配管は、高温の水が大量に流れるため、その接続部に
は使用時に割れ，腐食が発生しないような長期にわたる
高い信頼性が要求される。このような原子力プラントの
配管にはステンレス鋼や炭素鋼が使用されてきた。この
うちステンレス鋼は、全面腐食は起こさないものの表面
のごく一部が優先的に腐食する孔食や、溶接時の熱影響
部の耐食性が低下し割れを起こす応力腐食割れ（ＳＣ
Ｃ）が発生する等の問題があるため、それらの問題を起
こしにくい炭素鋼が配管材料として多く使用されるよう
になった。2. Description of the Related Art Boiling water reactor (hereinafter referred to as BWR)
Since a large amount of high-temperature water flows through the pipe, its connection is required to have long-term high reliability so that cracks and corrosion do not occur during use. Stainless steel and carbon steel have been used for piping in such nuclear plants. Among them, stainless steel is stress corrosion cracking (SC) that causes pitting corrosion in which only a small part of the surface preferentially corrodes but does not cause general corrosion, and reduces the corrosion resistance of the heat-affected zone during welding and causes cracking.
Because of problems such as occurrence of C), carbon steel, which is less likely to cause these problems, has come to be widely used as a piping material.

【０００３】炭素鋼管同士の接続部における腐食の問題
としては、例えば外径の異なる炭素鋼管を嵌めあわせて
接続するソケット接続において、鋼管の隙間部が優先的
に腐食する隙間腐食がある。これは、狭い隙間部分にあ
る液体中の酸素濃度と隙間以外の表面（自由表面と称す
る）に接する液体中の酸素濃度が異なることにより、局
部電池を形成し、隙間部分の腐食が加速される現象であ
る。炭素鋼配管の接続部の腐食を防止する方法として、
この隙間をなくするため、差し込み継手部に樹脂のよう
な弾性変形をおこすインサート材を挿入して防食する方
法（実開昭57−205475号公報）が知られている。As a problem of corrosion at the connecting portion between carbon steel pipes, there is crevice corrosion in which the gap portion of the steel pipe is preferentially corroded in a socket connection for fitting and connecting carbon steel pipes having different outer diameters. This is because the oxygen concentration in the liquid in the narrow gap and the oxygen concentration in the liquid in contact with the surface other than the gap (referred to as the free surface) are different, forming a local battery and accelerating the corrosion of the gap. It is a phenomenon. As a method of preventing the corrosion of carbon steel pipe connections,
In order to eliminate this gap, there is known a method (corresponding to Japanese Utility Model Laid-Open No. 57-205475) in which an insert material that causes elastic deformation such as resin is inserted into the insertion joint portion to prevent corrosion.

【０００４】[0004]

【発明が解決しようとする課題】しかし、近年炭素鋼管
溶接部において溶接の入熱により熱影響部が生成し、そ
の部分が応力腐食割れ（ＳＣＣ）を起こしたと考えられ
る腐食損傷トラブルが顕在化して来た。上記のインサー
ト材の挿入は隙間腐食の防止には効果が期待できるもの
の、配管の溶接を伴う接続には、効果が期待できない。
また、熱影響部が生成していない隙間部に樹脂等の弾性
変形を起こすインサート材を挿入したとしても、完全に
隙間をなくすることはできないため、場合によっては隙
間腐食の度合いを加速する結果となる場合も考えられ
る。However, in recent years, a heat-affected zone is generated by the heat input of welding in a carbon steel pipe weld zone, and a corrosion damage trouble that is considered to have caused stress corrosion cracking (SCC) in that zone has become apparent. I came. Although the insertion of the above-mentioned insert material can be expected to be effective in preventing crevice corrosion, it cannot be expected to be effective in the connection involving welding of pipes.
In addition, even if an insert material that causes elastic deformation such as resin is inserted in the gap where the heat-affected zone is not created, the gap cannot be completely eliminated, and as a result, the degree of crevice corrosion may be accelerated. It is possible that

【０００５】本発明は原子炉等のプラントにおける配管
の接続部の耐食性を改善し、長期の使用に耐えうるよう
にすることを目的とする。An object of the present invention is to improve the corrosion resistance of the connecting portion of piping in a plant such as a nuclear reactor so that it can withstand long-term use.

【０００６】[0006]

【課題を解決するための手段】上記目的を達成するた
め、本発明によれば、同一組成の金属管同士の接続にお
いて、該金属管の接続部近傍に該金属管を構成する金属
より腐食電位が５０〜３００ｍＶ(vs. SHE）高い金属を
設けることを特徴とする金属管の接続方法が提供され
る。この場合同一組成とは、炭素鋼同士であれば、その
組成の成分が全く同一であることを意味するものではな
い。ステンレス鋼と炭素鋼のような全く成分の異なる金
属管ではないという程度の意味であり、例えば、炭素鋼
中の成分であるＭｏの組成が数％異なっていたとして
も、本発明の作用には全く影響を与えない。In order to achieve the above object, according to the present invention, when connecting metal pipes having the same composition, the corrosion potential of the metal forming the metal pipe is higher than that of the metal forming the metal pipe in the vicinity of the connecting portion of the metal pipes. A metal tube connecting method is provided, which comprises providing a metal having a high voltage of 50 to 300 mV (vs. SHE). In this case, the same composition does not mean that the components of the composition are completely the same for carbon steels. This means that they are not metal pipes having completely different components such as stainless steel and carbon steel. For example, even if the composition of Mo, which is a component in carbon steel, differs by several percent, the function of the present invention is not affected. It has no effect.

【０００７】また、上記同一組成の金属管が炭素鋼管で
あることが好ましい。炭素鋼管とは通常のＪＩＳ規格で
規定されているようにＣ，Ｓｉ，Ｍｎを含む鉄のことで
ある。Further, it is preferable that the metal pipe having the same composition is a carbon steel pipe. The carbon steel pipe is iron containing C, Si, and Mn as defined by the ordinary JIS standard.

【０００８】また、上記金属管の接続方法が溶接である
場合、本発明の効果が顕著に表れる。When the method of connecting the metal pipes is welding, the effect of the present invention is remarkable.

【０００９】また、本発明の効果は、接続する部分の金
属管の一方の外径が他方の内径より小さい金属管を嵌め
あわせて接続するソケット接続の場合により顕著な効果
が得られる。これは、突合せ接続に比べて隙間の部分の
面積が大きいためである。Further, the effect of the present invention is more remarkable in the case of socket connection in which a metal pipe having one outer diameter of a metal pipe to be connected is smaller than the inner diameter of the other metal is fitted and connected. This is because the area of the gap is larger than that of the butt connection.

【００１０】また、溶接接続した場合、最も熱影響が大
きい接続部の初層溶接部近傍に前記した腐食電位が５０
〜３００ｍＶ(vs. SHE）高い金属を設けることが好まし
い。また、隙間部分の腐食を防止するため、管体が重な
る部分の少なくとも一部に、前記腐食電位が５０〜３０
０ｍＶ(vs. SHE）高い金属を介在させることが好まし
い。Further, in the case of welding connection, the above-mentioned corrosion potential is 50 in the vicinity of the first layer welded portion of the connection portion having the greatest heat effect.
It is preferable to provide a metal of about 300 mV (vs. SHE) higher. Further, in order to prevent the corrosion of the gap portion, the corrosion potential is 50 to 30 at least in a part where the pipes overlap.
It is preferable to interpose a metal having a high 0 mV (vs. SHE).

【００１１】また、前記した腐食電位が５０〜３００ｍ
Ｖ(vs. SHE）高い金属を管体に巻くように帯状に設ける
ことが好ましい。Further, the above-mentioned corrosion potential is 50 to 300 m.
It is preferable to provide a metal having a high V (vs. SHE) in a strip shape so as to be wound around the tubular body.

【００１２】また、前記した腐食電位が５０〜３００ｍ
Ｖ(vs. SHE）高い金属は前記外径が小さい鋼管の外周表
面、前記内径が大きい鋼管の内周表面の片面または両面
に設けることが好ましい。Further, the above-mentioned corrosion potential is 50 to 300 m.
The metal having a high V (vs. SHE) is preferably provided on one or both surfaces of the outer peripheral surface of the steel pipe having a small outer diameter and the inner peripheral surface of the steel pipe having a large inner diameter.

【００１３】前記腐食電位が５０〜３００ｍＶ(vs. SH
E）高い金属はＣｄ，Ｉｎ，Ｔｌ，Ｃｏ，Ｎｉ，Ｓｎ，
Ｐｂから選ばれた１種以上の金属またはそれらの合金で
あることが好ましい。The corrosion potential is 50 to 300 mV (vs. SH
E) High metals are Cd, In, Tl, Co, Ni, Sn,
It is preferably one or more metals selected from Pb or alloys thereof.

【００１４】また、腐食電位が５０〜３００ｍＶ(vs. S
HE）高い金属がステンレス鋼であることが好ましい。The corrosion potential is 50 to 300 mV (vs. S
HE) It is preferred that the high metal is stainless steel.

【００１５】また、腐食電位が５０〜３００ｍＶ(vs. S
HE）高い金属を設ける方法は、溶射，スパッタ，ＣＶ
Ｄ，ＰＶＤ，めっき法等の薄膜形成技術を用いて金属表
面に形成してもよい。The corrosion potential is 50 to 300 mV (vs. S
HE) The method of providing high metal is thermal spraying, sputtering, CV
It may be formed on the metal surface by using a thin film forming technique such as D, PVD, or a plating method.

【００１６】また、本発明は厚さ１mm以下のステンレス
鋼の薄板を、炭素鋼からなる管体の端部にまきつける工
程と，炭素鋼管のソケット部に前記管体を挿入する工程
と，前記ソケット部の端部を管体の外部から溶接する工
程により施すことが最も望ましい。Further, according to the present invention, a step of winding a stainless steel thin plate having a thickness of 1 mm or less on an end portion of a carbon steel pipe body, a step of inserting the pipe body into a socket portion of the carbon steel pipe, and the socket Most preferably, it is applied by a process of welding the end of the portion from the outside of the pipe body.

【００１７】また、本発明によれば、管の端部の少なく
とも一部に、管を構成する金属より腐食電位が５０〜３
００ｍＶ(vs. SHE）高い金属が前記管を構成する金属
に、少なくともその一部が接触しているように設けられ
ていることを特徴とする金属管が提供される。この場
合、管を構成する金属が炭素鋼であることが好ましい。Further, according to the present invention, at least a part of the end portion of the pipe has a corrosion potential of 50 to 3 as compared with the metal constituting the pipe.
There is provided a metal tube, wherein a metal having a high value of 00 mV (vs. SHE) is provided so as to contact at least a part of the metal forming the tube. In this case, the metal forming the tube is preferably carbon steel.

【００１８】また、本発明によれば、金属管をつなぎあ
わせて構成されたプラントの配管において、少なくとも
接続している部分の金属管の一方の外径が他方の内径よ
り小さい金属管の接続部の該金属管が重なる部分に、管
を構成する金属より腐食電位が５０〜３００ｍＶ(vs. S
HE）高い金属が介在していることを特徴とするプラント
の配管が提供される。この場合も、金属管を構成する金
属が炭素鋼であることが好ましい。Further, according to the present invention, in the piping of a plant constructed by connecting metal pipes, at least one of the connecting metal pipes has an outer diameter smaller than the inner diameter of the other metal pipe connecting portion. Of the metal pipe, the corrosion potential of which is 50 to 300 mV (vs. S
HE) Plumbing of a plant is provided, characterized by the interposition of high metals. Also in this case, the metal forming the metal tube is preferably carbon steel.

【００１９】[0019]

【作用】炭素鋼管同士の溶接によるソケット接続方法を
例に取り説明する。図２に接続部断面の模式図を示す。
外径の小さい管を内径の大きい管に挿入し、内径の大き
い管の端部を肉盛り溶接して接続する方法である。この
場合、管と管の間３に水などの液体が入り込み隙間腐食
を発生させる。また、肉盛り溶接部は、鋼管自体に比べ
て耐食性が劣るため、鋼管に比べて初層溶接部４の腐食
が著しい。本発明では、管と管の間３に、管を構成する
金属より腐食電位が５０〜３００ｍＶ(vs.SHE）高い金
属を挿入することにより、初層溶接部，管体自体の耐食
性を向上することができることを見い出しなされたもの
である。[Operation] A socket connection method by welding carbon steel pipes will be described as an example. FIG. 2 shows a schematic view of a cross section of the connecting portion.
This is a method in which a pipe having a small outer diameter is inserted into a pipe having a large inner diameter, and the ends of the pipe having a large inner diameter are welded together by welding. In this case, liquid such as water enters the space 3 between the pipes to cause crevice corrosion. Further, since the build-up welded portion is inferior in corrosion resistance to the steel pipe itself, the first layer welded portion 4 is significantly corroded as compared to the steel pipe. In the present invention, a metal having a corrosion potential of 50 to 300 mV (vs.SHE) higher than that of the metal forming the pipe is inserted between the pipes 3 to improve the corrosion resistance of the first layer weld and the pipe itself. It was discovered that it was possible.

【００２０】図３に本発明の一態様を示す。管を構成す
る金属より腐食電位が５０〜３００ｍＶ(vs. SHE）高い
金属は、隙間腐食を防止するため管と管の間３に挿入さ
れるが、これは弾性体のように隙間をできるだけ少なく
するという目的ではなく、電気化学的な作用により腐食
を抑制するものである。FIG. 3 shows one embodiment of the present invention. A metal with a corrosion potential of 50 to 300 mV (vs. SHE) higher than that of the metal that composes the pipe is inserted between the pipes to prevent crevice corrosion. The purpose is not to do so, but to suppress corrosion by an electrochemical action.

【００２１】電気化学的な作用により防食する方法とし
ては、トタン板のように基板材料である鉄よりイオン化
傾向の大きい亜鉛を、基板表面にコーティングする犠牲
陽極による防食がある。この場合、犠牲陽極である亜鉛
がすべて亜鉛イオンとして溶け出し消失するまでは、基
板の鉄の腐食を防ぐことができる。しかし、隙間腐食
は、雰囲気酸素濃度の違いによる局部電池の形成によ
り、腐食が加速されるため、この方法を隙間腐食に適用
しても、表面の亜鉛が短時間に消耗してしまう。すなわ
ち、長期間の使用に耐えなければならないプラント配管
の接続部に用いるには適していない。As a method of preventing corrosion by an electrochemical action, there is a corrosion prevention using a sacrificial anode that coats the surface of the substrate with zinc, which has a higher ionization tendency than iron as a substrate material such as a galvanized sheet. In this case, corrosion of iron in the substrate can be prevented until all of the zinc, which is the sacrificial anode, dissolves out as zinc ions and disappears. However, crevice corrosion is accelerated by the formation of local cells due to the difference in oxygen concentration in the atmosphere, and therefore even if this method is applied to crevice corrosion, surface zinc is consumed in a short time. That is, it is not suitable for use as a connecting portion of plant piping that must endure long-term use.

【００２２】発明者らは、このような隙間が生じる接続
部を有するプラント配管の接続方法として、長期にわた
り腐食が少ない方法を検討中に本発明に到った。具体的
にはオートクレーブを用いた長期腐食試験により従来の
方法に比べ腐食量の少ない方法を見い出した。The inventors of the present invention have reached the present invention while investigating a method of connecting a plant pipe having a connection portion in which such a gap is generated, which is less corrosive over a long period of time. Specifically, a long-term corrosion test using an autoclave was found to find a method with a smaller amount of corrosion than the conventional method.

【００２３】すなわち、炭素鋼管同士を嵌めあわせて接
合する際、生ずる隙間部にステンレス鋼（SUS304鋼；１
８Ｃｒ−８Ｎｉ−Ｆｅ balance）の円筒を挿入すると、
母材である炭素鋼にほとんど腐食が生じないことを新た
に見い出した。ステンレス鋼は炭素鋼に比べて腐食電位
は高く（すなわちイオン化傾向が小さく）、腐食環境下
で接触させると炭素鋼が優先的に腐食されるはずであ
る。しかしながら実験の結果、炭素鋼，ステンレス鋼と
もにほとんど腐食していないことがわかった。さらにス
テンレス鋼の他にＮｉまたはＮｉ基合金も同様の効果を
有することを見い出した。実験の結果、この効果は炭素
鋼だけでなく、他の金属材料を用いた管に対しても、管
を構成する金属より腐食電位が５０〜３００ｍＶ(vs. S
HE）高い金属を接続部の近傍に一部が電気的に接触する
ように配することにより得られることがわかった。この
効果の原因として以下のことが考えられる。That is, when carbon steel pipes are fitted and joined to each other, stainless steel (SUS304 steel; 1
8Cr-8Ni-Fe balance) cylinder,
It has been newly found that the base material, carbon steel, is hardly corroded. Stainless steel has a higher corrosion potential than carbon steel (that is, has a smaller ionization tendency), and carbon steel should preferentially corrode when contacted in a corrosive environment. However, as a result of experiments, it was found that neither carbon steel nor stainless steel was corroded. Furthermore, it has been found that Ni or Ni-based alloys have similar effects in addition to stainless steel. As a result of the experiment, this effect is not only for carbon steel but also for pipes using other metal materials, the corrosion potential is 50 to 300 mV (vs.
It has been found that it is possible to obtain it by arranging HE) high metal so that a part of it is in electrical contact with the vicinity of the connection part. The cause of this effect is considered as follows.

【００２４】高温高圧水中ではSUS304鋼より炭素鋼の方
がイオン化傾向が大きく、かつ腐食電位は卑側であるこ
とから、密着隙間内では腐食によって炭素鋼から鉄イオ
ンと電子が発生し、発生した電子をSUS304鋼が消費して
安定な保護皮膜を形成するために、SUS304鋼はほとんど
腐食しない。また、炭素鋼から発生した鉄イオンは隙間
内の炉水と反応してち密な保護皮膜を炭素鋼の表面に形
成するために、局部的な腐食（孔食）の発生や全面腐食
の成長が抑制される。隙間内ではこれらの腐食反応が繰
り返し起るために、炭素鋼表面は常に安定した保護皮膜
で覆われることから、高温高圧水中において腐食割れや
ＳＣＣの発生が抑制されるのである。In high-temperature and high-pressure water, carbon steel has a greater ionization tendency than SUS304 steel, and the corrosion potential is on the base side. Therefore, iron ions and electrons are generated from carbon steel due to corrosion in the close contact gap. Since SUS304 steel consumes electrons to form a stable protective film, SUS304 steel hardly corrodes. Further, iron ions generated from carbon steel react with the reactor water in the gap to form a dense protective film on the surface of carbon steel, which causes local corrosion (pitting corrosion) and general corrosion growth. Suppressed. Since these corrosion reactions occur repeatedly in the gap, the surface of the carbon steel is always covered with a stable protective film, so that the occurrence of corrosion cracking and SCC in high-temperature high-pressure water is suppressed.

【００２５】この効果は、高温水中における管を構成す
る金属と、防食のために設ける金属との腐食電位差が腐
食の抑制に良いバランスをもたらしているためと考えら
れる。従って、腐食電位差が５０ｍＶより小さい場合
は、その効果があまり期待できず、３００ｍＶより大き
い場合は、犠牲陽極効果により管を構成する金属が腐食
されるため好ましくない。図１１に（鉄との）腐食電位
差と鉄の腐食量の関係を示す。This effect is considered to be because the difference in corrosion potential between the metal forming the pipe in high temperature water and the metal provided for corrosion prevention provides a good balance in suppressing corrosion. Therefore, when the corrosion potential difference is smaller than 50 mV, the effect cannot be expected so much, and when it is larger than 300 mV, the metal constituting the tube is corroded by the sacrificial anode effect, which is not preferable. FIG. 11 shows the relationship between the corrosion potential difference (with iron) and the corrosion amount of iron.

【００２６】防食のための金属は、接合部近傍に接触さ
せれば良い。接触部近傍とは、上記作用の及ぶ範囲であ
り、ソケット継手部の重なる範囲と考えればよい。The metal for corrosion protection may be brought into contact with the vicinity of the joint. The vicinity of the contact portion is a range in which the above-mentioned action is exerted, and may be considered as a range in which the socket joint portion overlaps.

【００２７】本発明の作用は、あらゆる組成の金属管に
適用される。しかし、管材をステンレス鋼のような表面
に不働態被膜が形成される材料で構成した場合、この不
働態被膜が、上記した作用を妨害する働きをするため、
本発明の効果が充分期待できない場合も考えられる。本
発明の効果が最も期待できるのは、全面腐食が起こるよ
うな耐食性のそれほど優れない金属材料を用いたときで
あり、特に炭素鋼管を用いた場合本発明の効果が最も期
待できる。The operation of the present invention is applicable to metal tubes of any composition. However, when the pipe material is made of a material such as stainless steel on which a passivation film is formed, this passivation film acts to hinder the above-mentioned action,
There may be cases where the effects of the present invention cannot be fully expected. The effect of the present invention can be most expected when using a metal material having not so excellent corrosion resistance that causes general corrosion, and particularly when a carbon steel pipe is used, the effect of the present invention can be expected most.

【００２８】また、本発明は管を機械的なかしめのよう
な方法で接続した場合でも原理上その効果が期待できる
が、溶接により接合した場合、最もその効果を発揮す
る。例えば、炭素鋼管同士を溶接により接続する場合、
溶接金属としては炭素鋼を用いるのが普通であるが、こ
の溶接金属は組成は炭素鋼のままであるため、腐食電位
は管材とほとんど同じである。しかし、溶接の入熱によ
り熱影響を受けるため、耐食性は管部の炭素鋼に比べ劣
化する。そのような劣化した肉盛り溶接部に電気的に接
触するように炭素鋼より腐食電位が５０ｍＶ〜３００ｍ
Ｖ高い金属を配することにより肉盛り溶接部の耐食性を
も向上することができるからである。このことから、接
続部の初層溶接部近傍に腐食電位が５０〜３００ｍＶ(v
s. SHE）高い金属を設けることが最も好ましいのであ
る。In the present invention, the effect can be expected in principle even when the pipes are connected by a method such as mechanical caulking, but the effect is most exerted when they are joined by welding. For example, when connecting carbon steel pipes by welding,
Carbon steel is usually used as the weld metal, but since the composition of this weld metal remains carbon steel, the corrosion potential is almost the same as that of the pipe material. However, the corrosion resistance is deteriorated as compared with the carbon steel of the pipe portion, because it is affected by the heat input of welding. The corrosion potential is 50 mV to 300 m higher than that of carbon steel so as to make electrical contact with such a deteriorated buildup weld.
This is because by arranging a metal having a high V, it is possible to improve the corrosion resistance of the build-up weld portion. From this, the corrosion potential near the first layer weld of the joint is 50 to 300 mV (v
s. SHE) It is most preferable to provide a high metal.

【００２９】また、本発明は図１２に示すように配管突
合せ溶接部の裏当て金部に腐食電位が５０〜３００ｍＶ
(vs. SHE）高い金属を設けることにより裏当て金部の耐
食性向上を図ることもできる。Further, according to the present invention, as shown in FIG. 12, the corrosion potential is 50 to 300 mV in the backing metal part of the butt welded pipe.
(vs. SHE) By providing a high metal, the corrosion resistance of the backing metal part can be improved.

【００３０】また、本発明は、隙間部の面積の大きいソ
ケット接続部に用いることによりその効果を充分発揮す
る。すなわち、接続する部分の金属管の一方の外径が他
方の内径より小さいことが好ましい。Further, according to the present invention, the effect can be sufficiently exerted by using the socket connecting portion having a large gap area. That is, it is preferable that one outer diameter of the metal pipe at the connecting portion is smaller than the inner diameter of the other.

【００３１】同様に接続部の複数個の管体が重なる部分
の少なくとも一部に、前記腐食電位が５０〜３００ｍＶ
(vs. SHE）高い金属を介在させることが好ましいことが
わかる。Similarly, the corrosion potential is 50 to 300 mV in at least a part of a portion where a plurality of pipes of the connecting portion overlap.
It can be seen that it is preferable to interpose a (vs. SHE) high metal.

【００３２】介在させる方法としては、いろいろな方法
が考えられるが薄い金属板を帯状に径の小さい管の外周
部に巻きつけるか、または径の大きい管の内周部にはり
つけるように設けることが、施工上最も簡便である。Various methods are conceivable as an intervening method, but a thin metal plate is wound in a strip shape around the outer circumference of a small diameter tube or is attached so as to be attached to the inner circumference of a large diameter tube. It is the simplest in construction.

【００３３】腐食電位の高い金属としては、Ｃｄ，Ｉ
ｎ，Ｔｌ，Ｃｏ，Ｎｉ，Ｓｎ，Ｐｂから選ばれた１種以
上の金属またはそれらの合金であってもよい。これら金
属は硬度の小さい(軟らかい)金属であるため、管に巻き
つけやすいという利点がある。また、管材として炭素鋼
を用いる場合は、ステンレス鋼を介在させる金属として
用いることが好ましい。ステンレス鋼はそれ自身耐食性
に優れた金属であるため、炭素鋼の耐食性を向上すると
ともに自身も腐食しにくい構成とすることができる。介
在させる金属の耐食性が非常に悪い金属である場合、管
材の腐食を抑制するより前に、自身が腐食してしまい、
実用上問題となることが考えられる。Metals having a high corrosion potential include Cd, I
It may be one or more metals selected from n, Tl, Co, Ni, Sn and Pb or alloys thereof. Since these metals have low hardness (soft), they have an advantage that they can be easily wound around a pipe. When carbon steel is used as the pipe material, it is preferable to use it as a metal with stainless steel interposed. Since stainless steel itself is a metal having excellent corrosion resistance, it is possible to improve the corrosion resistance of carbon steel and also to make it resistant to corrosion. If the intervening metal has very poor corrosion resistance, it will corrode itself before suppressing the corrosion of the pipe material,
It may be a problem in practical use.

【００３４】介在させる金属は、施工前に接続部に巻き
つけることが最も簡便であるが、大量に生産する場合
は、接続部に予め溶射，スパッタ，ＣＶＤ，ＰＶＤ，め
っき法などの薄膜形成方法を用いて金属を付着させてお
いたものを用いることが好ましい。この場合、管体の製
造工程においてこのような金属膜を管の端部に設ける工
程を組み込んで製造した管を用いられる。これにより、
プラント建設現場での配管作業を能率良く行うことがで
きる。ただし、少ない数の配管を行う場合は、厚さ１mm
以下のステンレス鋼の薄板を、炭素鋼からなる管体の端
部にまきつけ、炭素鋼管のソケット部に前記管体を挿入
し、前記ソケット部の端部を管体の外部から溶接する工
程を経て炭素鋼管を接続する方法が最も簡便である。The metal to be interposed is most conveniently wound around the connecting portion before construction, but in the case of mass production, thin film forming methods such as thermal spraying, sputtering, CVD, PVD, and plating are applied to the connecting portion in advance. It is preferable to use the one to which the metal is attached by using. In this case, a tube manufactured by incorporating a step of providing such a metal film at the end of the tube in the tube manufacturing process is used. This allows
The piping work at the plant construction site can be performed efficiently. However, when using a small number of pipes, the thickness is 1 mm.
The following stainless steel thin plate is sprinkled on the end of a tube made of carbon steel, the tube is inserted into the socket of the carbon steel tube, and the end of the socket is welded from the outside of the tube. The most convenient method is to connect carbon steel pipes.

【００３５】[0035]

【実施例】【Example】

（実施例１）供試材は市販の炭素鋼で表１に化学組成を
示す。(Example 1) The test material is a commercially available carbon steel, and its chemical composition is shown in Table 1.

【００３６】[0036]

【表１】 試験条件は次に示すとおりである。[Table 1] The test conditions are as follows.

【００３７】[0037]

【表２】 表３に試験結果をまとめて示す。[Table 2] The test results are summarized in Table 3.

【００３８】[0038]

【表３】 図１は試験後の試験片断面写真を示す。本試験条件はＳ
ＣＣの加速試験として、溶存酸素を実機条件（０.２pp
m）より高い８ppm に調整して実施した。[Table 3] FIG. 1 shows a photograph of a cross section of the test piece after the test. This test condition is S
As an accelerated CC test, dissolved oxygen was used under actual conditions (0.2 pp
m), which was higher than 8 ppm.

【００３９】長時間（１万時間）浸漬試験による炭素鋼
の高温高圧水中での最大腐食深さは隙間を形成しない場
合、炭素鋼母材が２２０μｍで溶接継手部は４００μｍ
を示す。これらはいずれも局部腐食でＳＣＣには至らな
いが、隙間なしの場合には２００μｍ以上の腐食深さが
示された。本実験では隙間形成材としてSUS304鋼の０.
０５mm 厚さの箔，テフロン及びグラファイトウールを
用い腐食深さに及ぼす隙間形成材の影響を検討した。表
３及び図１から明らかなように、最大腐食深さは隙間な
しの場合に比べて隙間を形成した場合の方がいずれの場
合においても小さく示され、隙間の付与が腐食の抑制に
有効であることが示された。この場合、隙間形成による
腐食の抑制効果はグラファイトウール＜テフロン≪SUS3
04箔の順に大となり、特にSUS304箔の腐食抑制効果が顕
著に示された。The maximum corrosion depth of the carbon steel in the high temperature and high pressure water by the immersion test for a long time (10,000 hours) is 220 μm for the carbon steel base material and 400 μm for the welded joint when no gap is formed.
Indicates. Although none of these resulted in SCC due to local corrosion, a corrosion depth of 200 μm or more was shown when there was no gap. In this experiment, SUS304 steel was used as the gap forming material.
The effect of the crevice forming material on the corrosion depth was investigated using 05 mm thick foil, Teflon and graphite wool. As is clear from Table 3 and FIG. 1, the maximum corrosion depth is shown to be smaller in any case with a gap than in the case without a gap, and the provision of a gap is effective in suppressing corrosion. It was shown to be. In this case, the effect of suppressing the corrosion due to the gap formation is graphite wool <Teflon << SUS3
04 foils increased in order, and the corrosion inhibition effect of SUS304 foil was particularly remarkable.

【００４０】このように炭素鋼の高温高圧水中における
腐食はSUS304箔と炭素鋼が密着隙間を形成することによ
り著しく抑制され、炭素鋼の腐食割れ及びＳＣＣは炭素
鋼にSUS304箔を密着あるいは接合することにより、抑制
あるいは防止できることが明らかとなった。この効果は
SUS304箔のみならず、炭素鋼（鉄）よりイオン化傾向が
小さく、かつ腐食電位が貴側の金属または特殊金属ある
いは金属層または特殊金属層と炭素鋼とを密着あるいは
接合することにより発揮できるものと考えられる。As described above, the corrosion of carbon steel in high temperature and high pressure water is remarkably suppressed by the formation of the adhesion gap between the SUS304 foil and the carbon steel, and the corrosion cracking and SCC of the carbon steel adhere or join the SUS304 foil to the carbon steel. Therefore, it became clear that it can be suppressed or prevented. This effect
Not only SUS304 foil, but a material that has a smaller ionization tendency than carbon steel (iron) and has a corrosion potential of a noble side metal or special metal, or a metal layer or special metal layer and carbon steel can be brought into close contact with or joined to each other. Conceivable.

【００４１】図２は従来の炭素鋼管ソケット溶接方法を
示す。図３から図８は本発明による炭素鋼管ソケット溶
接方法を示す。本発明は炭素鋼管ソケット溶接部の接水
初層溶接部に異種金属または異種金属層を設けることに
より、高温高圧水中におけるソケット溶接部の耐食性を
向上させることにある。本発明によれば、ＢＷＲ運転中
における炭素鋼管溶接継手部の高耐食化が図られ、プラ
ントの長寿命化が図れるので安全性や経済性の点におい
ても効果がある。FIG. 2 shows a conventional carbon steel pipe socket welding method. 3 to 8 show a carbon steel pipe socket welding method according to the present invention. The present invention is to improve the corrosion resistance of a socket weld in high-temperature high-pressure water by providing a dissimilar metal or a dissimilar metal layer in the wetted first layer weld of the carbon steel pipe socket weld. According to the present invention, the corrosion resistance of the carbon steel pipe welded joint portion can be improved during the BWR operation, and the life of the plant can be extended, which is also effective in terms of safety and economy.

【００４２】（実施例２)実験に用いたボルト−ナット
は表１に示した供試材より作製した。試験条件を図９に
示す。Example 2 The bolts and nuts used in the experiment were made from the test materials shown in Table 1. The test conditions are shown in FIG.

【００４３】表４に腐食試験結果をまとめて示す。図１
０に試験対象部（ボルト断面）を模式的に示す。本試験
では炭素鋼−炭素鋼，炭素鋼−テフロン−炭素鋼，炭素
鋼−SUS304−炭素鋼の組み合わせによる炭素鋼の隙間腐
食挙動について検討した。図１０の試験部（Ａ）におけ
る腐食生成物の厚さは表４に示すように、炭素鋼−SUS3
04−炭素鋼の組み合わせが８μｍと最も少ない。この場
合も炭素鋼の隙間腐食感受性はSUS304鋼と炭素鋼を密着
させることにより著しく低減し、炭素鋼の耐食性はSUS3
04鋼と密着隙間を形成することにより向上することが明
らかとなった。Table 4 shows a summary of the corrosion test results. FIG.
0 schematically shows a test target portion (bolt cross section). In this test, the crevice corrosion behavior of carbon steel by the combination of carbon steel-carbon steel, carbon steel-Teflon-carbon steel, carbon steel-SUS304-carbon steel was examined. As shown in Table 4, the thickness of the corrosion product in the test part (A) of FIG.
The smallest combination of 04-carbon steel is 8 μm. In this case as well, the crevice corrosion susceptibility of carbon steel is significantly reduced by bringing SUS304 steel and carbon steel into close contact, and the corrosion resistance of carbon steel is SUS3.
04 It became clear that it is improved by forming a close contact gap with the steel.

【００４４】[0044]

【表４】 （実施例３)表１に示す組成の炭素鋼を組み合わせたソ
ケット溶接継手を製作した。[Table 4] (Example 3) A socket welded joint in which carbon steels having the compositions shown in Table 1 were combined was manufactured.

【００４５】継手の形状を図１３に示す。外径３９mm，
内径２１.４mm の大径管２の内側を端面から奥に１３.
５mmまで切削し、外径２７.２mm，内径１９.４mm の小
径管１を１１.５mm 大径管の切削部に押し込む。このと
き、押し込んだ小径管と大径管の切削部に生じた隙間部
にステンレス箔円筒３を嵌めこんで取付け、大径管２の
端部を溶接して溶接部４を形成した。ステンレス箔円筒
は小径管１の先端から１３mmの位置まで押し込む。すな
わち、ステンレス箔円筒は厚さ０.２５mm ，内径２７.
２mm，長さ１３mmの円筒となっている。The shape of the joint is shown in FIG. Outer diameter 39mm,
Inside the large diameter tube 2 with an inner diameter of 21.4 mm from the end face to the back 13.
Cut to 5 mm and push the small diameter pipe 1 with an outer diameter of 27.2 mm and an inner diameter of 19.4 mm into the cut part of a 11.5 mm large diameter pipe. At this time, the stainless steel foil cylinder 3 was fitted and mounted in the clearance formed in the cut portion of the small diameter pipe and the large diameter pipe pushed, and the end portion of the large diameter pipe 2 was welded to form the welded portion 4. The stainless steel foil cylinder is pushed in from the tip of the small diameter tube 1 to a position 13 mm. That is, the stainless steel foil cylinder has a thickness of 0.25 mm and an inner diameter of 27.
It is a cylinder with a length of 2 mm and a length of 13 mm.

【００４６】このようにして作製したソケット溶接体の
小径管１を差し込み部先端から８０mm，大径管２を溶接
部先端から４０mmの位置で切断したものと、ステンレス
箔を用いずに同様の方法で作製したものを、温度２８８
℃，溶存酸素８ppm ，圧力８５kg／cm2 の高温高圧純水
中で腐食試験を行った。The same method as the one obtained by cutting the small-diameter pipe 1 of the socket welded body produced in this way at a position of 80 mm from the tip of the insertion part and the large-diameter pipe 2 at 40 mm from the tip of the welded part without using a stainless foil. The one prepared in
A corrosion test was conducted in high temperature and high pressure pure water at a temperature of 85 ° C., dissolved oxygen of 8 ppm and a pressure of 85 kg / cm 2 .

【００４７】試験結果を表５に示す。The test results are shown in Table 5.

【００４８】[0048]

【表５】 ステンレス箔を設けることにより、ソケット溶接隙間部
の耐食性の低下はほとんど認められず、本発明の効果が
顕著に認められた。[Table 5] By providing the stainless steel foil, the corrosion resistance of the socket welding gap was hardly reduced, and the effect of the present invention was remarkably observed.

【００４９】（実施例４)表６に示す組成の低合金鋼か
らなる鋼管（内径１００mm）を突合せ溶接した後、図１
２に示すように突合せ溶接部の裏当て金（鋼管と同じ組
成）との隙間部にSUS304鋼の箔を挿入したものを作製し
た。これを実施例３と同様の腐食試験を行ったが耐食性
の低下はほとんど認められなかった。(Embodiment 4) Steel pipes (inner diameter 100 mm) made of low alloy steel having the composition shown in Table 6 were butt-welded, and then, as shown in FIG.
As shown in 2, a SUS304 steel foil was inserted into the gap between the butt weld and the backing metal (same composition as the steel pipe). This was subjected to the same corrosion test as in Example 3, but almost no deterioration in corrosion resistance was observed.

【００５０】[0050]

【表６】 [Table 6]

【００５１】[0051]

【発明の効果】本発明によれば、ＢＷＲ炉水環境におい
て良好な耐高温高圧水ＳＣＣ性を有する炭素鋼管溶接継
手が提供できる。また、ＢＷＲの安全性が確保され、ひ
いては原子炉プラントの長寿命化を図ることができる。According to the present invention, it is possible to provide a carbon steel pipe welded joint having good high temperature and high pressure water SCC resistance in a BWR reactor water environment. In addition, the safety of the BWR is ensured, and the life of the nuclear reactor plant can be extended.

【図面の簡単な説明】[Brief description of drawings]

【図１】曲げ試験後の試験片断面の金属組織を示す写
真。FIG. 1 is a photograph showing a metal structure of a cross section of a test piece after a bending test.

【図２】従来のソケット溶接方法を示す図。FIG. 2 is a diagram showing a conventional socket welding method.

【図３】本発明の実施例を示す図。FIG. 3 is a diagram showing an embodiment of the present invention.

【図４】本発明の実施例を示す図。FIG. 4 is a diagram showing an embodiment of the present invention.

【図５】本発明の実施例を示す図。FIG. 5 is a diagram showing an embodiment of the present invention.

【図６】本発明の実施例を示す図。FIG. 6 is a diagram showing an example of the present invention.

【図７】本発明の実施例を示す図。FIG. 7 is a diagram showing an example of the present invention.

【図８】本発明の実施例を示す図。FIG. 8 is a diagram showing an embodiment of the present invention.

【図９】本発明の実施中の試験条件を示す図。FIG. 9 is a diagram showing test conditions during the implementation of the present invention.

【図１０】本発明の実施中の試験対象部の模式図。FIG. 10 is a schematic diagram of a test target portion during implementation of the present invention.

【図１１】本発明の実施例を示す図。FIG. 11 is a diagram showing an example of the present invention.

【図１２】本発明の実施例を示す図。FIG. 12 is a diagram showing an example of the present invention.

【図１３】本発明の実施例を示す図。FIG. 13 is a diagram showing an example of the present invention.

【符号の説明】[Explanation of symbols]

１…小径管、２…大径管、３…ステンレス箔、４…溶接
部。1 ... small diameter pipe, 2 ... large diameter pipe, 3 ... stainless steel foil, 4 ... welded part.

───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 庁内整理番号 ＦＩ 技術表示箇所 Ｇ２１Ｃ 19/02 Ｇ２１Ｃ 19/02 Ｊ ─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. 6 Identification code Internal reference number FI Technical display location G21C 19/02 G21C 19/02 J

Claims (16)

【特許請求の範囲】[Claims] 【請求項１】同一組成の金属管同士の接続において、 該金属管の接続部近傍に該金属管を構成する金属より腐
食電位が５０〜３００ｍＶ(vs. SHE）高い金属を設ける
ことを特徴とする金属管の接続方法。1. When connecting metal pipes having the same composition, a metal having a corrosion potential higher by 50 to 300 mV (vs. SHE) than the metal forming the metal pipe is provided in the vicinity of the connecting portion of the metal pipes. How to connect metal pipes. 【請求項２】請求項１記載の同一組成の金属管が炭素鋼
管であることを特徴とする金属管の接続方法。2. A method of connecting metal pipes according to claim 1, wherein the metal pipes having the same composition are carbon steel pipes. 【請求項３】請求項１または２記載の接続方法が溶接で
あることを特徴とする金属管の接続方法。3. A method for connecting metal pipes, wherein the connecting method according to claim 1 or 2 is welding. 【請求項４】請求項１または２記載の接続方法が溶接で
あり、かつ少なくとも接続する部分の金属管の一方の外
径が他方の内径より小さいことを特徴とする金属管の接
続方法。4. The method for connecting metal pipes according to claim 1 or 2, wherein the connecting method is welding, and at least the outer diameter of one of the metal pipes to be connected is smaller than the inner diameter of the other. 【請求項５】請求項１または２記載の接続方法が溶接で
あり、かつ接続部の初層溶接部近傍に前記腐食電位が５
０〜３００ｍＶ(vs. SHE）高い金属を設けることを特徴
とする金属管の接続方法。5. The connection method according to claim 1 or 2 is welding, and the corrosion potential is 5 in the vicinity of the first layer weld of the connection.
A method for connecting metal pipes, characterized in that a metal having a high value of 0 to 300 mV (vs. SHE) is provided. 【請求項６】請求項１または２記載の接続方法が溶接で
あり、かつ接続部の複数個の管体が重なる部分の少なく
とも一部に、前記腐食電位が５０〜３００ｍＶ(vs. SH
E）高い金属を介在させることを特徴とする金属管の接
続方法。6. The connection method according to claim 1 or 2 is welding, and the corrosion potential is 50 to 300 mV (vs. SH) in at least a part of a portion where a plurality of pipes of the connection portion overlap.
E) A method of connecting metal pipes, characterized in that a high metal is interposed. 【請求項７】請求項１または２記載の接続方法が溶接で
あり、かつ接続部の複数個の管体が重なる部分に、前記
腐食電位が５０〜３００ｍＶ(vs. SHE）高い金属を帯状
に設けることを特徴とする金属管の接続方法。7. The method of connection according to claim 1 or 2 is welding, and a metal having a high corrosion potential of 50 to 300 mV (vs. SHE) is formed into a strip shape at a portion where a plurality of pipes of the connection portion overlap. A method for connecting metal pipes, which is characterized by being provided. 【請求項８】請求項１または２記載の接続方法が溶接で
あり、かつ少なくとも接続する部分の金属管の一方の外
径が他方の内径より小さく、更に前記腐食電位が５０〜
300ｍＶ(vs. SHE）高い金属を前記外径が小さい鋼管の
外周表面、前記内径が大きい鋼管の内周表面の片面また
は両面に設けることを特徴とする金属管の接続方法。8. The connecting method according to claim 1 or 2 is welding, and at least the outer diameter of one of the connecting metal pipes is smaller than the inner diameter of the other, and the corrosion potential is 50 to 50.
A method for connecting metal pipes, wherein a metal having a high 300 mV (vs. SHE) is provided on one or both of the outer peripheral surface of the steel pipe having a small outer diameter and the inner peripheral surface of the steel pipe having a large inner diameter. 【請求項９】請求項２〜８のいずれかに記載の腐食電位
が５０〜３００ｍＶ(vs. SHE）高い金属がＣｄ，Ｉｎ，
Ｔｌ，Ｃｏ，Ｎｉ，Ｓｎ，Ｐｂから選ばれた１種以上の
金属またはそれらの合金であることを特徴とする金属管
の接続方法。9. A metal having a high corrosion potential of 50 to 300 mV (vs. SHE) according to any one of claims 2 to 8 is Cd, In,
A method for connecting metal pipes, which is one or more metals selected from Tl, Co, Ni, Sn, and Pb or alloys thereof. 【請求項１０】請求項２〜８のいずれかに記載の腐食電
位が５０〜３００ｍＶ(vs. SHE）高い金属がステンレス
鋼であることを特徴とする金属管の接続方法。10. A method for connecting metal pipes, wherein the metal having a high corrosion potential of 50 to 300 mV (vs. SHE) according to any one of claims 2 to 8 is stainless steel. 【請求項１１】請求項１〜８のいずれかに記載の前記金
属を設ける方法が、溶射，スパッタ，ＣＶＤ，ＰＶＤ，
めっき法から選ばれた方法を用いることを特徴とする炭
素鋼管の接続方法。11. A method of providing the metal according to claim 1, wherein the method includes thermal spraying, sputtering, CVD, PVD,
A method for connecting carbon steel pipes, characterized in that a method selected from plating methods is used. 【請求項１２】厚さ１mm以下のステンレス鋼の薄板を、
炭素鋼からなる管体の端部にまきつける工程と、 炭素鋼管のソケット部に前記管体を挿入する工程と、 前記ソケット部の端部を管体の外部から溶接する工程、
からなることを特徴とする炭素鋼管の接続方法。12. A stainless steel thin plate having a thickness of 1 mm or less,
A step of winding the tube body made of carbon steel on the end portion, a step of inserting the tube body into the socket portion of the carbon steel tube, and a step of welding the end portion of the socket portion from the outside of the pipe body,
A method for connecting carbon steel pipes, which comprises: 【請求項１３】管の端部の少なくとも一部に、管を構成
する金属より腐食電位が５０〜３００ｍＶ(vs. SHE）高
い金属が前記管を構成する金属に、少なくともその一部
が接触しているように設けられていることを特徴とする
金属管。13. A metal having a corrosion potential of 50 to 300 mV (vs. SHE) higher than that of the metal forming the pipe contacts at least a part of the end of the pipe with the metal forming the pipe, at least part of which is in contact with the metal forming the pipe. A metal tube characterized by being provided as follows. 【請求項１４】請求項１３の管を構成する金属が炭素鋼
であることを特徴とする金属管。14. A metal tube, wherein the metal composing the tube of claim 13 is carbon steel. 【請求項１５】金属管をつなぎあわせて構成されたプラ
ントの配管において、 少なくとも接続している部分の金属管の一方の外径が他
方の内径より小さい金属管の接続部の該金属管が重なる
部分に、管を構成する金属より腐食電位が５０〜３００
ｍＶ(vs. SHE）高い金属が介在していることを特徴とす
るプラントの配管。15. In a plant pipe constituted by connecting metal pipes, at least one metal pipe in a connecting portion has an outer diameter smaller than an inner diameter of the other metal pipe, and the metal pipes overlap each other. The part has a corrosion potential of 50 to 300 compared to the metal forming the pipe.
MV (vs. SHE) Plant piping characterized by interposition of high metal. 【請求項１６】請求項１５の金属管を構成する金属が炭
素鋼であることを特徴とするプラントの配管。16. A pipe for a plant, wherein the metal composing the metal pipe according to claim 15 is carbon steel.
JP7110261A 1995-04-12 1995-04-12 Method for welding socket Pending JPH08281440A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP7110261A JPH08281440A (en) 1995-04-12 1995-04-12 Method for welding socket

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP7110261A JPH08281440A (en) 1995-04-12 1995-04-12 Method for welding socket

Publications (1)

Publication Number Publication Date
JPH08281440A true JPH08281440A (en) 1996-10-29

Family

ID=14531214

Family Applications (1)

Application Number Title Priority Date Filing Date
JP7110261A Pending JPH08281440A (en) 1995-04-12 1995-04-12 Method for welding socket

Country Status (1)

Country Link
JP (1) JPH08281440A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010038842A (en) * 2008-08-07 2010-02-18 Toshiba Corp Boiling water reactor
JP2012236216A (en) * 2011-05-12 2012-12-06 Japan Atom Power Co Ltd:The Structural material for socket welding pipe fitting

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010038842A (en) * 2008-08-07 2010-02-18 Toshiba Corp Boiling water reactor
JP2012236216A (en) * 2011-05-12 2012-12-06 Japan Atom Power Co Ltd:The Structural material for socket welding pipe fitting

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