JP2013158774A - Welding method, weld bonding structure and stainless steel welded structure - Google Patents

Welding method, weld bonding structure and stainless steel welded structure Download PDF

Info

Publication number
JP2013158774A
JP2013158774A JP2012019605A JP2012019605A JP2013158774A JP 2013158774 A JP2013158774 A JP 2013158774A JP 2012019605 A JP2012019605 A JP 2012019605A JP 2012019605 A JP2012019605 A JP 2012019605A JP 2013158774 A JP2013158774 A JP 2013158774A
Authority
JP
Japan
Prior art keywords
phase
welding
mode
solidification
welded
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
JP2012019605A
Other languages
Japanese (ja)
Inventor
Tetsuya Toyoda
哲也 豊田
Kyoji Obata
亨司 小畠
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 GE Nuclear Energy Ltd
Original Assignee
Hitachi GE Nuclear Energy 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 GE Nuclear Energy Ltd filed Critical Hitachi GE Nuclear Energy Ltd
Priority to JP2012019605A priority Critical patent/JP2013158774A/en
Publication of JP2013158774A publication Critical patent/JP2013158774A/en
Pending legal-status Critical Current

Links

Images

Abstract

PROBLEM TO BE SOLVED: To prevent the development of cracks on a crack developing route even when stress corrosion cracking occurs at a portion adjacent to a weld heat affected zone and cracks develop to the inside of a material.SOLUTION: In a welding method, a butting section of a stainless steel joint part is subjected to edge preparation, and then a welding metal is built up at the butting section of the edge prepared portion. After a section as the weld bonding section is subjected to edge preparation, the edge prepared butting section is welded by using a welding metal having a solidification mode of two-phase solidification microstructure (AF mode) comprising pro-eutectic austenite and δ ferrite in solidification phase, thereby forming a build-up layer having a solidification microstructure wherein the continuity of an interface between δ ferrite phase and γ austenite phase is divided.

Description

本発明は溶接施工方法及び溶接接合構造並びにステンレス鋼溶接構造物に係り、例えば、原子力発電プラントの高温純水に接して使用されるオーステナイト系ステンレス鋼製配管等に適用するに好適な溶接施工方法及び溶接接合構造並びにステンレス鋼溶接構造物に関する。   The present invention relates to a welding method, a welded joint structure, and a stainless steel welded structure. For example, a welding method suitable for application to austenitic stainless steel pipes used in contact with high-temperature pure water of a nuclear power plant. And a welded joint structure and a stainless steel welded structure.

原子力発電プラントでは、高温純水に接して使用されるオーステナイト系ステンレス鋼製の配管及び炉内構造物等の溶接部近傍において、応力腐食割れによるひびの損傷事例が報告されている。   In nuclear power plants, there have been reports of crack damage cases due to stress corrosion cracking in the vicinity of welded parts such as austenitic stainless steel pipes and furnace structures used in contact with high-temperature pure water.

応力腐食割れとは、材料条件、環境条件、応力条件が一定の条件で重畳した場合に発現する経年劣化事象の一つであり、これまでに、様々な対策技術が開発され、原子力発電プラントの配管及び炉内構造物等に適用されてきた。   Stress corrosion cracking is one of aging degradation events that occur when material conditions, environmental conditions, and stress conditions are superimposed under certain conditions. Various countermeasure technologies have been developed so far, It has been applied to piping and furnace structures.

例えば、炭素含有量の高いステンレス鋼を溶接した際、熱影響部の結晶粒界上にクロム炭化物が形成されることにより、その近傍にクロム欠乏層ができ、耐食性が低下して応力腐食割れ発生の原因となることが分かったため、材料面からの改善策として、ステンレス鋼中の炭素含有量を減らし、溶接時の熱鋭敏化を抑制した低炭素系ステンレス鋼が開発され、原子力発電プラントの配管及び炉内構造物等に適用されている。   For example, when stainless steel with a high carbon content is welded, chromium carbide is formed on the grain boundaries in the heat affected zone, so that a chromium deficient layer is formed in the vicinity, and corrosion resistance is reduced and stress corrosion cracking occurs. As a material improvement measure, low-carbon stainless steel has been developed as a measure to improve material quality by reducing the carbon content in stainless steel and suppressing thermal sensitization during welding. And applied to furnace structures.

一般的に、ステンレス鋼製の配管及び構造物を溶接する場合には、図1に示すように、溶接接合するプラント構成部材の各端面に加工された開先を、互いに突合せ、この突合せ部に溶接金属を多層盛りして溶接する。   In general, when welding stainless steel pipes and structures, as shown in FIG. 1, the grooves machined on the end faces of the plant components to be welded are butted together, and this butt part is joined. Weld multiple layers of weld metal.

近年、低炭素系ステンレス鋼を使用した再循環系配管等において、溶接熱影響部3の表面に加工硬化層4が存在すると応力腐食割れが発生し、これが溶接熱影響部3を進展した上、溶接金属2に達している事例報告されている。   In recent years, in a recirculation piping using low-carbon stainless steel, when a work hardened layer 4 is present on the surface of the weld heat affected zone 3, stress corrosion cracking has occurred, and this has advanced the weld heat affected zone 3. A case report of reaching weld metal 2 has been reported.

尚、一般的に溶接熱影響部3に加工硬化層4から発生した応力腐食割れは、溶接残留応力との関係から、表面から板厚方向に徐々に傾きながら溶接金属2へ進展することが知られている。日本機械学会 発電用原子力設備維持規格に従い、健全性が確認された場合は、割れを有したまま継続運転を認めているが、配管や構造物等の溶接部における信頼性向上の観点から、溶接熱影響部や溶接金属中での応力腐食割れの進展を抑制することは、極めて重要な対策の一つと考えられている。   In general, it is known that stress corrosion cracks generated from the work hardened layer 4 in the weld heat affected zone 3 progress to the weld metal 2 while being gradually inclined from the surface in the plate thickness direction due to the relationship with the welding residual stress. It has been. The Japan Society of Mechanical Engineers, in accordance with the standards for maintaining nuclear power facilities for power generation, if soundness is confirmed, continuous operation is permitted with cracks. From the viewpoint of improving the reliability of welded parts such as pipes and structures, Suppressing the development of stress corrosion cracking in heat affected zone and weld metal is considered as one of the most important measures.

この溶接熱影響部や溶接金属中での応力腐食割れの進展を抑制する対策として、耐応力腐食割れ性を向上した配管の溶接接合工法が、特許文献1で提案されている。特許文献1に記載されている配管の溶接接合工法は、配管の接合端部近傍の内面に、配管の母材よりも耐応力腐食割れ性に優れた材料を用いて肉盛を施し、この肉盛された配管の接合端部に、肉盛部の少なくとも一部を残して開先を形成し、肉盛部同士を突合わせて溶接接合している。   As a measure for suppressing the progress of stress corrosion cracking in the weld heat affected zone and the weld metal, Patent Document 1 proposes a welding joint method for piping with improved stress corrosion cracking resistance. In the welding joint method for piping described in Patent Document 1, the inner surface in the vicinity of the joint end of the pipe is overlaid using a material that is more excellent in stress corrosion cracking resistance than the base material of the pipe. A groove is formed at the joining end portion of the piled pipe leaving at least a part of the built-up portion, and the built-up portions are butted together and welded.

一方、特許文献2には、配管の肉盛溶接方法が記載されている。この特許文献2では、配管を溶接する前に、配管の開先加工部に応力腐食割れ進展方向と交差する方向に溶接金属のデンドライト組織を成長させた肉盛溶接層を形成し、その後、肉盛溶接層同士を溶接接合している。配管の開先加工部において、配管の外面側から内面側に向かって肉盛を行うことによって、上記したように、応力腐食割れ進展方向と交差する方向に溶接金属のデンドライト組織を成長させることができる。   On the other hand, Patent Document 2 describes a method for overlay welding of piping. In this patent document 2, before welding the pipe, a build-up weld layer in which a dendrite structure of the weld metal is grown in a direction intersecting the stress corrosion crack propagation direction is formed in the grooved portion of the pipe. The welded layers are welded together. As described above, it is possible to grow a dendritic structure of the weld metal in the direction intersecting with the stress corrosion cracking propagation direction by building up from the outer surface side to the inner surface side of the pipe in the groove processed portion of the pipe. it can.

この配管の溶接接合構造では、配管内面側の溶接熱影響部付近で発生した応力腐食割れが、応力腐食割れ進展方向と交差する方向に形成されたデンドライト組織によって、溶接金属の内部に進展することを抑制している。   In this welded joint structure of pipes, stress corrosion cracks that occur near the weld heat affected zone on the inner surface side of the pipes are propagated into the weld metal by a dendrite structure formed in a direction that intersects the direction of stress corrosion crack propagation. Is suppressed.

更に、特許文献3には、配管内面側の溶接熱影響部の近傍でプラント構成部材の表面に発生した応力腐食割れにより生じたき裂が、溶接金属の内部に進展することを抑制している溶接接合構造が記載されている。   Further, Patent Document 3 discloses a weld that suppresses a crack generated by stress corrosion cracking generated on the surface of a plant component near the welding heat-affected zone on the inner surface side of the pipe from propagating into the weld metal. The joint structure is described.

この方法では、開先加工部に複数層の溶接パスによる肉盛部を有し、この肉盛部において、下層である第1溶接と、この第1溶接パスと隣り合って第1溶接パスの上に施された上層である第2溶接パスの境界に沿って、下層の溶接パス内に微細化したδフェライト相5Bが形成される。   In this method, the grooved portion has a built-up portion by a plurality of layers of welding passes, and in this built-up portion, the first welding that is a lower layer and the first welding pass adjacent to the first welding pass are provided. A refined δ ferrite phase 5B is formed in the lower welding path along the boundary of the second welding path which is the upper layer applied on the upper layer.

δフェライト相5Bは、あたかも、ある方向に伸びるδフェライト相5A(図2参照)の、その方向での連続性が分断された状態であり、δフェライト相5Aよりも長さが短くなっており、また、δフェライト相5Bとγオーステナイト相6の間の界面の連続性が、δフェライト相5Aとγオーステナイト相6の間の界面の連続性よりも短くなっている。   The δ ferrite phase 5B is a state in which the continuity in the direction of the δ ferrite phase 5A (see FIG. 2) extending in a certain direction is divided, and the length is shorter than that of the δ ferrite phase 5A. Further, the continuity of the interface between the δ ferrite phase 5B and the γ austenite phase 6 is shorter than the continuity of the interface between the δ ferrite phase 5A and the γ austenite phase 6.

そして、特許文献3では、隣り合う溶接パスの境界に沿って存在する連続性が分断されたδフェライト相5Bとγオーステナイト相6の領域が、200μm〜1000μmの幅を有して形成され、これにより、応力腐食割れの進展経路であるδフェライト相5Bとγオーステナイト相6の界面を分断できるため、配管内面側の溶接熱影響部3の近傍でプラント構成部材の表面に発生した応力腐食割れにより生じたき裂が、溶接金属2の内部に向かって進展することを抑制している。   And in patent document 3, the area | region of the (delta) ferrite phase 5B and the (gamma) austenite phase 6 in which the continuity which exists along the boundary of an adjacent welding path was divided | segmented is formed with the width | variety of 200 micrometers-1000 micrometers, Therefore, the interface between the δ ferrite phase 5B and the γ austenite phase 6, which is the path of stress corrosion cracking, can be divided. The generated crack is restrained from progressing toward the inside of the weld metal 2.

特開2005−28405号公報JP 2005-28405 A 特開2009−39734号公報JP 2009-39734 A 特願2011−206809号公報Japanese Patent Application No. 2011-206809

溶接熱影響部近傍より応力腐食割れが発生し、材料内部へき裂が進展した場合でも、き裂進展経路上でき裂の進展を抑制することができれば、当該部の健全性は確保できる。   Even when stress corrosion cracking occurs near the weld heat affected zone and the crack propagates into the material, if the crack growth can be suppressed along the crack propagation path, the soundness of the portion can be secured.

本発明の目的とするところは、溶接熱影響部近傍より応力腐食割れが発生し、材料内部へき裂が進展した場合でも、き裂進展経路上でき裂の進展を抑制することができる溶接施工方法及び溶接接合構造並びにステンレス鋼溶接構造物を提供することにある。   The object of the present invention is to provide a welding method capable of suppressing crack propagation on the crack propagation path even when stress corrosion cracking occurs near the weld heat-affected zone and the crack propagates into the material. And providing a welded joint structure and a stainless steel welded structure.

本発明の溶接施工方法は、上記目的を達成するために、ステンレス鋼接合部となる突き合わせ部に開先加工を施し、その後に、該開先加工部の突合せ部に溶接金属を肉盛りする溶接施工方法において、前記溶接接合部となる部分に開先加工を施した後に、該開先加工の突合せ部に、凝固形態が初晶オーステナイト+δフェライトの二相凝固組織(AFモード)の凝固モードを有する溶接金属を用いて溶接し、δフェライト相とγオーステナイト相の界面の連続性が分断された凝固組織を持つ肉盛層を形成することを特徴とする。   In order to achieve the above object, the welding construction method of the present invention performs welding on a butt portion to be a stainless steel joint, and then welds a weld metal on the butt portion of the groove processing portion. In the construction method, after performing groove processing on the portion to be the welded joint, the solidification mode of the two-phase solidified structure (AF mode) of the primary crystal austenite + δ ferrite is applied to the butt portion of the groove processing. It welds using the welding metal which has, and forms the built-up layer with the solidification structure | tissue where the continuity of the interface of (delta) ferrite phase and (gamma) austenite phase was parted.

また、本発明の溶接接合構造は、上記目的を達成するために、ステンレス鋼接合部となる突合せ部に開先加工が施され、該開先加工部の突合せ部に溶接金属が肉盛されている溶接接合構造において、前記溶接接合部となる部分に開先加工が施された該開先加工の突合せ部に、凝固形態が初晶オーステナイト+δフェライトの二相凝固組織(AFモード)の凝固モードを有する溶接金属が溶接されて、δフェライト相とγオーステナイト相の界面の連続性が分断された凝固組織を持つ肉盛層が形成され、該肉盛層に開先加工を施して突合せた該開先加工部に、初晶δフェライト+オーステナイトの二相凝固組織(FAモード)の凝固モードを有する溶接金属が肉盛溶接されて接合されていることを特徴とする。   Further, in order to achieve the above object, the welded joint structure of the present invention is provided with a groove processing on a butt portion which becomes a stainless steel joint portion, and a weld metal is built up on the butt portion of the groove processed portion. In the welded joint structure, the solidified mode of the two-phase solidified structure (AF mode) of primary austenite + δ ferrite is formed in the butt portion of the grooved work in which the grooved part is grooved A weld layer having a solidified structure in which the continuity of the interface between the δ ferrite phase and the γ austenite phase is divided is formed by welding a weld metal having A weld metal having a solidification mode of a two-phase solidified structure (FA mode) of primary crystal δ ferrite + austenite is welded and joined to the groove processed portion.

また、本発明のステンレス鋼溶接構造物は、上記目的を達成するために、上記構成の溶接接合構造を有することを特徴とする。   Moreover, in order to achieve the above object, the stainless steel welded structure according to the present invention has a welded joint structure having the above-described configuration.

本発明によれば、溶接熱影響部近傍より応力腐食割れが発生し、材料内部へき裂が進展した場合でも、き裂進展経路上でき裂の進展を抑制することができる。   According to the present invention, even when a stress corrosion crack occurs from the vicinity of the weld heat affected zone and the crack propagates into the material, it is possible to suppress the crack propagation on the crack propagation path.

プラント構成部材である原子力発電プラントの再循環系配管の従来の溶接接合構造を示す縦断面図である。It is a longitudinal cross-sectional view which shows the conventional welding joining structure of the recirculation system piping of the nuclear power plant which is a plant structural member. 図1に示す溶接部の溶接凝固組織を示す説明図である。It is explanatory drawing which shows the weld solidification structure of the weld part shown in FIG. 図1に示す肉盛層の肉盛凝固組織を示す説明図である。It is explanatory drawing which shows the build-up solidification structure | tissue of the build-up layer shown in FIG. 本発明の溶接施工方法の実施例1であり、突合せ部の溶接方法を説明するための工程図である。It is Example 1 of the welding construction method of this invention, and is process drawing for demonstrating the welding method of a butt | matching part. 本発明の溶接施工方法の実施例1であり、開先加工部の溶接方法を説明するための工程図である。It is Example 1 of the welding construction method of this invention, and is process drawing for demonstrating the welding method of a groove processing part.

溶接金属部を応力腐食割れが進展する場合、その進展経路はマクロ的な溶接金属のデンドライト組織の連続性及び方向性だけではなく、ミクロ的なδフェライトとγオーステナイトの界面にも影響を受けることが確認されている。   When stress corrosion cracking progresses in the weld metal part, the path of growth is affected not only by the continuity and directionality of the macroscopic weld metal dendrite structure, but also by the microscopic interface between δ ferrite and γ austenite. Has been confirmed.

オーステナイト系ステンレス鋼の溶接材料では、溶接金属の凝固モード(凝固過程での初晶及び相変化のタイプ)が、溶接金属の化学組成によって決定される。   In austenitic stainless steel welding materials, the solidification mode of the weld metal (the type of primary crystal and phase change during the solidification process) is determined by the chemical composition of the weld metal.

ステンレス鋼溶接金属の凝固モードは、オーステナイト単相凝固組織(Aモード)、初晶オーステナイト+δフェライトの二相凝固組織(AFモード)、初晶δフェライト+オーステナイトの二相凝固組織(FAモード)、フェライト単相凝固組織(Fモード)の4つのタイプに分類される。   The solidification mode of stainless steel weld metal is austenite single phase solidification structure (A mode), primary austenite + δ ferrite two-phase solidification structure (AF mode), primary δ ferrite + austenite two-phase solidification structure (FA mode), It is classified into four types of ferrite single-phase solidified structure (F mode).

このような凝固モードの変化はCr当量/Ni当量の比で次のように整理できる。
A、AFモード:Cr当量/Ni当量≦1.48
FAモード:1.48≦Cr当量/Ni当量≦1.95
A、AFモード:1.95≦Cr当量/Ni当量
ここで、Cr当量およびNi当量は次のように求められる。
Cr当量=(%Cr)+(%Mo)+1.5(%Si)+0.5(%Nb)
Ni当量=(%Ni)+30(%C)+0.5(%Mn)
本発明で用いるFAモードとAFモードの溶接金属の溶接凝固組織は、図2及び図3と同様である。FAモードでは、δフェライト相5Aとγオーステナイト相6の界面が連続性を持った溶接凝固組織となり、AFモードでは、δフェライト相5Bとγオーステナイト相6の界面の連続性が分断された溶接凝固組織となりやすいことが知られている。
Such a change in the solidification mode can be arranged as follows by the ratio of Cr equivalent / Ni equivalent.
A, AF mode: Cr equivalent / Ni equivalent ≦ 1.48
FA mode: 1.48 ≦ Cr equivalent / Ni equivalent ≦ 1.95
A, AF mode: 1.95 ≦ Cr equivalent / Ni equivalent Here, the Cr equivalent and the Ni equivalent are determined as follows.
Cr equivalent = (% Cr) + (% Mo) +1.5 (% Si) +0.5 (% Nb)
Ni equivalent = (% Ni) +30 (% C) +0.5 (% Mn)
The weld solidification structures of the FA mode and AF mode weld metals used in the present invention are the same as those shown in FIGS. In the FA mode, the interface between the δ ferrite phase 5A and the γ austenite phase 6 has a continuous weld solidification structure, and in the AF mode, the continuity at the interface between the δ ferrite phase 5B and the γ austenite phase 6 is divided. It is known that it is easy to become an organization.

尚、一般的にオーステナイト系ステンレス鋼(SUS304、SUS316等)は、溶接施工を考えた場合、FAモードの溶接金属を用いて溶接することが望ましいと考えられている。   In general, it is considered that austenitic stainless steel (SUS304, SUS316, etc.) is desirably welded using an FA mode weld metal in consideration of welding construction.

本発明では、溶接接合部となる部分に開先加工を施した後に、開先加工の突合せ部にAFモードの凝固モードを有する溶接金属により肉盛することで、連続性が分断されたδフェライト相5Bとγオーステナイト相6の凝固組織を有する肉盛層を開先加工の突合せ部に形成する。そして、肉盛溶接された突合せ部を、通常のFAモードの凝固モードを有する溶接金属により溶接することで、溶接金属に進展してきた応力腐食割れのき裂の進展を抑制することができる。   In the present invention, after the groove processing is performed on the portion to be the welded joint portion, the continuity is divided by overlaying with a weld metal having an AF mode solidification mode on the butt portion of the groove processing. A built-up layer having a solidified structure of phase 5B and γ-austenite phase 6 is formed at the butt portion of the groove processing. And the progress of the crack of the stress corrosion crack which has progressed to the weld metal can be suppressed by welding the butt-welded portion that has been welded with a weld metal having a normal FA mode solidification mode.

以上の検討結果を考慮した、本発明の実施例を以下に説明する。   An embodiment of the present invention will be described below in consideration of the above examination results.

本発明の実施例1としてステンレス鋼製配管の溶接施工方法を、図4及び図5を用いて説明する。   As a first embodiment of the present invention, a method for welding stainless steel pipes will be described with reference to FIGS.

図4(a)に示すように、溶接対象となる配管1の突合せ部に開先加工を施し、開先加工部7を形成する。尚、配管1の接液面側(図4の下側)は、より多くの肉盛を施すための開先形状とする。形成された開先加工部7に、AFモードの凝固モードを有する溶接金属(例えば、溶接ワイヤ)を用いて、開先加工部7上に複数の溶接を施し開先肉盛層8を形成する。この開先肉盛層8部は、δフェライト相5Bとγオーステナイト相6の連続性が分断された凝固組織を有して形成される。   As shown to Fig.4 (a), a groove processing is given to the butt | matching part of the piping 1 used as welding object, and the groove processing part 7 is formed. In addition, let the liquid-contact surface side (lower side of FIG. 4) of the piping 1 be a groove shape for performing more overlaying. Using the weld metal (for example, welding wire) which has solidification mode of AF mode to the formed groove processing part 7, a plurality of welding is given on the groove processing part 7, and the groove overlaying layer 8 is formed. . This 8 parts of the groove overlay layer is formed having a solidified structure in which the continuity of the δ ferrite phase 5B and the γ austenite phase 6 is divided.

突合せ部に開先肉盛層8を形成した後、図4(b)に示すように、開先肉盛層8に開先加工及び配管の内径を揃えるため配管内面切削加工(DC加工)を行い、開先加工部9及びDC加工部10を形成する。   After forming the groove overlay layer 8 at the butt portion, as shown in FIG. 4B, the groove cladding layer 8 is subjected to pipe inner surface machining (DC machining) in order to align the groove machining and the inner diameter of the pipe. The groove processing part 9 and the DC processing part 10 are formed.

その後、図5(a)、(b)及び(c)に示すように、開先加工部9を突合せ、開先加工部9に配管1の内面側から外面側へ向けて、通常のFAモードの凝固モードを有する溶接金属を用いて肉盛溶接11を施す。この時の溶接は、入熱量が20kj/cm未満で、TIG溶接にて実施する。TIG溶接以外に被覆アーク溶接或いはサブマージアーク溶接等を適用してもよい。   After that, as shown in FIGS. 5A, 5B, and 5C, the groove processing portion 9 is abutted, and the groove processing portion 9 is directed to the groove processing portion 9 from the inner surface side to the outer surface side in the normal FA mode. The build-up welding 11 is performed using a weld metal having a solidification mode. The welding at this time has a heat input of less than 20 kj / cm and is performed by TIG welding. In addition to TIG welding, covered arc welding, submerged arc welding, or the like may be applied.

このような本実施例によれば、応力腐食割れの進展経路となるδフェライト5Bとγオーステナイト6の界面の連続性が分断された金属組織を開先加工部7に形成するができ、溶接部に溶接熱影響部近傍より応力腐食割れが発生し、材料内部へき裂が進展した場合でも、溶接金属2に進展してきた応力腐食割れのき裂の進展を、開先肉盛層8の領域で抑制することができる。   According to such a present Example, the metal structure by which the continuity of the interface of (delta) ferrite 5B and (gamma) austenite 6 used as the propagation path of a stress corrosion crack was interrupted can be formed in the groove processing part 7, and a welding part can be formed. Even if a stress corrosion crack occurs in the vicinity of the weld heat-affected zone and the crack progresses into the material, the crack development of the stress corrosion crack that has progressed to the weld metal 2 Can be suppressed.

また、DC加工10により表面に加工硬化層4が形成されるが、当該部はδフェライト5Bとγオーステナイト6の界面の連続性が分断された開先肉盛層8となるため、応力腐食割れの発生を抑制することができる。   Moreover, although the work hardening layer 4 is formed on the surface by the DC processing 10, since the portion becomes the groove overlay layer 8 in which the continuity of the interface between the δ ferrite 5B and the γ austenite 6 is divided, the stress corrosion cracking occurs. Can be suppressed.

尚、上述した実施例では、原子力発電プラントの再循環系配管のステンレス鋼溶接構造物について説明したが、シュラウド等の溶接継手のステンレス鋼溶接構造物に適用できることは言うまでもない。   In addition, although the Example mentioned above demonstrated the stainless steel welded structure of the recirculation system piping of a nuclear power plant, it cannot be overemphasized that it is applicable to the stainless steel welded structure of welded joints, such as a shroud.

1…配管、2…溶接金属、3…溶接熱影響部、4…表面硬化層、5A、5B…δフェライト相、6…γオーステナイト相、7…開先加工部、8、9…開先肉盛層(AFモード)、10…DC加工部、11…肉盛溶接(FAモード)。   DESCRIPTION OF SYMBOLS 1 ... Piping, 2 ... Weld metal, 3 ... Weld heat affected zone, 4 ... Surface hardened layer, 5A, 5B ... delta ferrite phase, 6 ... gamma austenite phase, 7 ... groove processing part, 8, 9 ... groove meat Build-up (AF mode), 10 ... DC machining part, 11 ... Overlay welding (FA mode).

Claims (4)

ステンレス鋼接合部となる突き合わせ部に開先加工を施し、その後に、該開先加工部の突合せ部に溶接金属を肉盛りする溶接施工方法において、
前記溶接接合部となる部分に開先加工を施した後に、該開先加工の突合せ部に、凝固形態が初晶オーステナイト+δフェライトの二相凝固組織(AFモード)の凝固モードを有する溶接金属を用いて溶接し、δフェライト相とγオーステナイト相の界面の連続性が分断された凝固組織を持つ肉盛層を形成することを特徴とする溶接施工方法。
In the welding method of applying groove processing to the butt portion to be a stainless steel joint, and then overlaying a weld metal on the butt portion of the groove processing portion,
After performing groove processing on the portion to be the welded joint, a weld metal having a solidification mode of a two-phase solidification structure (AF mode) of primary austenite + δ ferrite is applied to the butt portion of the groove processing. And welding to form a built-up layer having a solidified structure in which the continuity of the interface between the δ ferrite phase and the γ austenite phase is divided.
請求項1に記載の溶接施工方法において、
前記開先加工の突合せ部に、前記δフェライト相とγオーステナイト相の界面の連続性が分断された凝固組織を持つ肉盛層を形成した後、該肉盛層に開先加工を施し、その後、該開先加工部を突合せると共に、該開先加工部に、初晶δフェライト+オーステナイトの二相凝固組織(FAモード)の凝固モードを有する溶接金属を用いて肉盛溶接することを特徴とする溶接施工方法。
In the welding construction method according to claim 1,
After forming a built-up layer having a solidified structure in which the continuity of the interface between the δ ferrite phase and the γ austenite phase is divided at the butt portion of the groove processing, the groove layer is subjected to groove processing, In addition, the groove processed portion is abutted, and overlay welding is performed on the groove processed portion using a weld metal having a solidification mode of a primary crystal δ ferrite + austenite two-phase solidified structure (FA mode). Welding construction method.
ステンレス鋼接合部となる突合せ部に開先加工が施され、該開先加工部の突合せ部に溶接金属が肉盛されている溶接接合構造において、
前記溶接接合部となる部分に開先加工が施された該開先加工の突合せ部に、凝固形態が初晶オーステナイト+δフェライトの二相凝固組織(AFモード)の凝固モードを有する溶接金属が溶接されて、δフェライト相とγオーステナイト相の界面の連続性が分断された凝固組織を持つ肉盛層が形成され、該肉盛層に開先加工を施して突合せた該開先加工部に、初晶δフェライト+オーステナイトの二相凝固組織(FAモード)の凝固モードを有する溶接金属が肉盛溶接されて接合されていることを特徴とする溶接接合構造。
In the welded joint structure in which the groove processing is performed on the butt portion that becomes the stainless steel joint portion, and the weld metal is built up on the butt portion of the groove processing portion,
A weld metal having a solidification mode of a two-phase solidification structure (AF mode) of primary austenite + δ ferrite is welded to a butt portion of the groove machining in which a groove machining is performed on a portion to be the weld joint. Then, a build-up layer having a solidified structure in which the continuity of the interface between the δ ferrite phase and the γ-austenite phase is divided is formed, A welded joint structure in which weld metal having a solidification mode of a primary phase δ ferrite + austenite (FA mode) is welded and welded.
請求項3に記載の溶接接合構造を有することを特徴とするステンレス鋼溶接構造物。   A stainless steel welded structure having the welded joint structure according to claim 3.
JP2012019605A 2012-02-01 2012-02-01 Welding method, weld bonding structure and stainless steel welded structure Pending JP2013158774A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2012019605A JP2013158774A (en) 2012-02-01 2012-02-01 Welding method, weld bonding structure and stainless steel welded structure

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2012019605A JP2013158774A (en) 2012-02-01 2012-02-01 Welding method, weld bonding structure and stainless steel welded structure

Publications (1)

Publication Number Publication Date
JP2013158774A true JP2013158774A (en) 2013-08-19

Family

ID=49171484

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2012019605A Pending JP2013158774A (en) 2012-02-01 2012-02-01 Welding method, weld bonding structure and stainless steel welded structure

Country Status (1)

Country Link
JP (1) JP2013158774A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2016124017A (en) * 2015-01-07 2016-07-11 日立Geニュークリア・エナジー株式会社 Welding joint structure and welding joint method
CN105772904A (en) * 2016-05-14 2016-07-20 山西阳煤化工机械(集团)有限公司 Butt welding method of small-diameter composite pipes
CN110449692A (en) * 2019-07-29 2019-11-15 南京工程学院 A kind of Phase Proportion control method of carbon steel surface overlaying two-phase anti-corrosion layer

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2016124017A (en) * 2015-01-07 2016-07-11 日立Geニュークリア・エナジー株式会社 Welding joint structure and welding joint method
CN105772904A (en) * 2016-05-14 2016-07-20 山西阳煤化工机械(集团)有限公司 Butt welding method of small-diameter composite pipes
CN110449692A (en) * 2019-07-29 2019-11-15 南京工程学院 A kind of Phase Proportion control method of carbon steel surface overlaying two-phase anti-corrosion layer
CN110449692B (en) * 2019-07-29 2021-07-20 南京工程学院 Phase proportion control method for carbon steel surface surfacing double-phase corrosion-resistant layer

Similar Documents

Publication Publication Date Title
JP6016170B2 (en) High toughness weld metal with excellent ductile tear strength
US8681923B2 (en) Method of manufacturing core shroud for nuclear power plant and structure of nuclear power plant
CN106232279B (en) Stepped design weld joint groove
KR101177254B1 (en) Butt welded joint of welded structure, and method for manufacturing same
JP5320196B2 (en) Dissimilar material overlay welding method and dissimilar material overlay welded structure
JP5984213B2 (en) Austenitic Fe-Ni-Cr alloy for cladding tubes with excellent weldability
JP2008212992A (en) T-welded joint structure having excellent fragility fracture resistance crack propagation stopping characteristics
JP2008043974A (en) Longitudinal seam welded joint of uoe steel pipe
JP2014055760A (en) Prevention maintenance repair method for weld of membrane panel for boiler and boiler device with this prevention maintenance repair
JP4915251B2 (en) Clad welded structure of low alloy steel base metal
JP2013158774A (en) Welding method, weld bonding structure and stainless steel welded structure
Yurioka et al. Recent developments in repair welding technologies in Japan
JP2007268551A (en) Multi-electrode one side submerged arc welding method
JP2005028405A (en) Pipe welding method, and structure of welded part
JP2012143784A (en) Method for preventing stress corrosion cracking of welded joint part and reduction in property of ultrasonic inspection
JP2011206809A (en) Welding method of plant component and weld-joined structure of plant component
JP5538079B2 (en) Clad steel material joining method and structure
JP6581777B2 (en) Welded joint structure and welded joint method
JP4929096B2 (en) Overlay welding method for piping
JP4660875B2 (en) Replacement method for RPV nozzle joint members
EP3911473A1 (en) Improvements in the welding of pipes
JP2002219585A (en) Structure and repairing method therefor
El-Batahgy Laser beam welding of austenitic stainless steels–Similar butt and dissimilar lap joints
JP6259666B2 (en) Manufacturing method of stainless clad steel
Sugitani et al. Experimental Study on Effects of Root Gap and Fillet Size of Welds on Joint Strength