JP2002113576A - Fillet welding structure - Google Patents
Fillet welding structureInfo
- Publication number
- JP2002113576A JP2002113576A JP2000309336A JP2000309336A JP2002113576A JP 2002113576 A JP2002113576 A JP 2002113576A JP 2000309336 A JP2000309336 A JP 2000309336A JP 2000309336 A JP2000309336 A JP 2000309336A JP 2002113576 A JP2002113576 A JP 2002113576A
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- JP
- Japan
- Prior art keywords
- plug
- welding
- fillet
- welded
- pipe
- Prior art date
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は高強度フェライト系
耐熱鋼よりなる検査プラグのすみ肉溶接構造に係り、特
にボイラ、化学プラント等で高温耐圧部に多用されるＣ
ｒ含有量が１〜２.２５重量％のＣｒフェライト系高強
度耐熱鋼、あるいはＣｒ含有量が１〜２.２５重量％の
Ｃｒ−Ｍｏフェライト系高強度耐熱鋼等よりなる種々の
検査プラグ（大径管の検査点検孔の栓）類や温度計、圧
力計の座等の溶接に適したすみ肉溶接構造に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fillet welded structure of an inspection plug made of a high-strength ferritic heat-resistant steel, and more particularly to a C which is frequently used in a high-temperature pressure-resistant part in a boiler, a chemical plant, or the like.
Various inspection plugs made of a Cr ferrite high strength heat resistant steel having an r content of 1 to 2.25% by weight or a Cr-Mo ferrite high strength heat resistant steel having a Cr content of 1 to 2.25% by weight ( The present invention relates to a fillet welded structure suitable for welding large diameter pipe inspection and inspection holes, thermometers, pressure gauge seats, and the like.
【０００２】[0002]
【従来の技術】発電用ボイラや各種熱交換器等において
は、厚肉で大径の配管類が高温、高圧の条件下で多数使
用されている。近年、特に大容量の発電用ボイラにおい
ては発電効率向上のため蒸気温度と圧力がさらに上昇し
てきており、配管材料としては、従来から使われてきた
Ｃｒ含有量１〜２.２５重量％のフェライト・パーライ
ト組織のＣｒ−Ｍｏ系低合金鋼に替わり、新しい高強度
フェライト系耐熱鋼が開発されている。これらの高強度
フェライト系耐熱鋼は、Ｎｂ、Ｖ等を添加し、焼ならし
−焼戻し熱処理によって、焼戻しベイナイト組織となる
ように成分設計されたもので、従来材に比べて格段に優
れた高温強度を有している。2. Description of the Related Art In power generation boilers and various heat exchangers, a large number of thick and large-diameter pipes are used under high temperature and high pressure conditions. In recent years, particularly in large-capacity power generation boilers, steam temperature and pressure have been further increased in order to improve power generation efficiency, and as a piping material, conventionally used ferrite with a Cr content of 1 to 2.25% by weight has been used. -A new high-strength ferritic heat-resistant steel has been developed in place of the pearlite structure Cr-Mo low alloy steel. These high-strength ferritic heat-resisting steels are designed to have a tempered bainite structure by normalizing and tempering heat treatments by adding Nb, V, etc., and have a much higher temperature than conventional materials. Has strength.
【０００３】このような高強度フェライト鋼を溶接接合
するための溶接材料は、配管材料である母材と同一成分
系の溶接材料を用いるのが原則であり、各々のフェライ
ト鋼に合わせた溶接材料が開発されている。しかしなが
ら、ＮｂやＶ等の合金元素が多く溶接金属の強度も高く
なることから溶接性は従来鋼に比べて低下し、高度な溶
接技術が必要となっている。このため配管同士の主要な
周溶接部には、高品質の溶接継手が得られる狭開先のＭ
ＡＧ（アルゴンガスメタルアーク）溶接法あるいはＴＩ
Ｇ（イナートガスタングステンアーク）溶接法が採用さ
れることが多い。As a welding material for welding and joining such a high-strength ferritic steel, it is a principle to use a welding material having the same composition as that of a base material which is a piping material. Is being developed. However, since there are many alloying elements such as Nb and V and the strength of the weld metal is high, the weldability is lower than that of conventional steels, and advanced welding techniques are required. For this reason, the main girth weld between the pipes has a narrow groove M that can provide a high quality welded joint.
AG (Argon Gas Metal Arc) welding method or TI
The G (inert gas tungsten arc) welding method is often employed.
【０００４】しかしながら、これら大径管の外面に取り
付けられる種々の検査プラグ（大径管の内面検査の点検
孔の栓）や温度計、圧力計の座等は、これまで自動化の
対象外で、被覆アーク溶接による、すみ肉溶接によって
取り付けられるのが一般的であり、溶接欠陥等が生じな
いように溶接施工に細心の注意を払う必要があった。However, various inspection plugs (plugs for inspection holes for the inner surface inspection of large diameter pipes), thermometers, pressure gauge seats, and the like attached to the outer surface of these large diameter pipes have not been subject to automation. It is generally mounted by fillet welding by covered arc welding, and it has been necessary to pay close attention to welding work so that welding defects and the like do not occur.
【０００５】図６および図７に、配管に取り付けられる
検査プラグの一例を示す。図６において、プラグ３は、
配管である母管１の周溶接部２の近傍に設置されてい
る。FIGS. 6 and 7 show an example of a test plug attached to a pipe. In FIG. 6, the plug 3 is
It is installed in the vicinity of the circumferential weld 2 of the mother pipe 1 which is a pipe.
【０００６】図７は、プラグ３の取り付け部の断面構造
の一例を示したものである。母管１に開けた孔の内面と
円筒形のプラグ３の外面の一部にネジを加工してあり、
プラグ３を母管１に、捩込んだ後、図８に示すようにプ
ラグ３の周囲をすみ肉溶接でシール溶接する。このネジ
部４は、ストレートネジあるいはテーパネジのいずれも
用いられている。このような捩込み構造の場合、溶接ル
ート部６の部分に、ネジ加工の都合上１ｍｍ程度のギャ
ップ（隙間）１１が生じる。このギャップ１１は溶接作
業自体には支障はないが、溶接金属５が凝固収縮する際
に、プラグ３の壁面が外側（図中の矢印方向）に引っ張
られて変形し、大きな弾性歪が残るため、溶接部近傍に
大きな残留応力が生じる。FIG. 7 shows an example of a sectional structure of a mounting portion of the plug 3. Screws are formed on the inner surface of the hole formed in the mother pipe 1 and a part of the outer surface of the cylindrical plug 3.
After screwing the plug 3 into the mother pipe 1, the periphery of the plug 3 is seal-welded by fillet welding as shown in FIG. The screw portion 4 uses either a straight screw or a tapered screw. In the case of such a screw-in structure, a gap (gap) 11 of about 1 mm is formed in the portion of the welding root portion 6 due to threading. This gap 11 does not hinder the welding operation itself, but when the weld metal 5 solidifies and contracts, the wall surface of the plug 3 is pulled outward (in the direction of the arrow in the drawing) and deformed, and large elastic strain remains. , Large residual stress is generated in the vicinity of the weld.
【０００７】一方、母管１に対して相対的に肉厚の薄い
プラグ３は溶接入熱によって過熱され易く、プラグ３側
の熱影響部で結晶粒が粗大になり易い。また、Ｎｂ、Ｖ
を添加したＣｒ−Ｍｏ系低合金鋼の場合は、溶接残留応
力が大きく、冶金的にも結晶粒の粗大化している部分で
はＳＲ（溶接後の熱処理）過程においてＳＲ割れを生じ
易いという問題があった。図８中に示す亀裂（割れ）７
は、典型的なＳＲ割れの発生位置を示したものである。On the other hand, the plug 3 having a relatively small thickness with respect to the mother tube 1 is easily heated by welding heat input, and crystal grains tend to become coarse in the heat-affected zone on the plug 3 side. Also, Nb, V
In the case of Cr-Mo based low alloy steel to which Cr is added, there is a problem that the welding residual stress is large and SR cracks are easily generated in a part where crystal grains are coarsened in a metallurgical manner in an SR (heat treatment after welding) process. there were. Crack (crack) 7 shown in FIG.
Shows a typical SR crack generation position.
【０００８】[0008]
【発明が解決しようとする課題】上述したごとく、従来
の配管に取り付けられる検査プラグは、母管に捩込み構
造で取り付けた後、すみ肉溶接される。この場合、溶接
ルート部にネジ加工の都合上、約１ｍｍ程度のギャップ
（隙間）生じ、この上にすみ肉溶接をすると、溶接金属
が凝固収縮する際にプラグの壁面が外側に引っ張られて
変形し、大きな弾性歪みが残り、溶接部近傍に大きな残
留応力が生じる。As described above, an inspection plug attached to a conventional pipe is attached to a mother pipe with a screw-in structure and then welded to a fillet. In this case, a gap (gap) of about 1 mm is formed in the welding root portion due to thread processing, and when fillet welding is performed thereon, when the weld metal solidifies and contracts, the wall surface of the plug is pulled outward and deformed. However, a large elastic strain remains, and a large residual stress occurs near the weld.
【０００９】一方、母管に対し肉厚の薄いプラグは溶接
の入熱により過熱され易く、プラグの熱影響部で結晶粒
が粗大になり易い。また、Ｎｂ、Ｖを添加したＣｒ−Ｍ
ｏ系低合金鋼の場合は、溶接残留応力が大きく、結晶粒
が粗大化している部分ではＳＲ過程において、ＳＲ割れ
が生じ易いという問題があった。On the other hand, a plug having a small thickness with respect to the mother tube is likely to be overheated by the heat input of welding, and crystal grains are likely to become coarse in the heat affected zone of the plug. In addition, Cr-M to which Nb and V are added
In the case of an o-based low alloy steel, there is a problem that the welding residual stress is large and SR cracks easily occur in the SR process in a portion where crystal grains are coarse.
【００１０】本発明の目的は、上記従来技術における問
題点を解消し、高強度フェライト系耐熱鋼よりなる点検
プラグのすみ肉溶接において、ＳＲ割れ等の溶接欠陥発
性の危険性を小さくして、溶接部の信頼性の向上をはか
ることができるすみ肉溶接構造を提供することにある。SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems in the prior art and to reduce the risk of occurrence of welding defects such as SR cracks in fillet welding of inspection plugs made of high-strength ferritic heat-resistant steel. Another object of the present invention is to provide a fillet welded structure capable of improving the reliability of a welded portion.
【００１１】[0011]
【課題を解決するための手段】上記本発明の目的を達成
するために、特許請求の範囲に記載のような構成とする
ものである。すなわち、請求項１に記載のように、Ｎ
ｂ、Ｖを合金元素として含有するフェライト系高強度耐
熱鋼よりなる捩込み式検査プラグを、配管外面の設定の
部位に捩込んだ後、上記プラグをすみ肉溶接する溶接構
造であって、上記プラグ側の外周部の一部が、上記配管
側の開口部の外縁部と密接して嵌合する上記プラグの座
を設け、該座に、上記プラグを捩込み、上記配管との接
触部を密接させることにより溶接部のルートギャップの
形成を抑止して、上記プラグを上記配管にすみ肉溶接し
た溶接構造とするものである。Means for Solving the Problems In order to achieve the above object of the present invention, the present invention is configured as described in the claims. That is, as described in claim 1, N
A welding structure in which a screw-in test plug made of a ferritic high-strength heat-resistant steel containing b and V as alloy elements is screwed into a set portion on the outer surface of the pipe, and then the plug is fillet-welded. A part of the outer periphery on the plug side is provided with a seat for the plug that fits closely with the outer edge of the opening on the pipe side, and the plug is screwed into the seat to form a contact portion with the pipe. The formation of the root gap at the welded portion is suppressed by close contact, so that the plug is welded to the pipe by fillet welding.
【００１２】また、請求項２において、Ｎｂ、Ｖを合金
元素として含有するフェライト系高強度耐熱鋼よりなる
捩込み式検査プラグを、配管外面の設定の部位に捩込ん
だ後、上記プラグをすみ肉溶接する溶接構造であって、
上記プラグ側の外周部の一部と上記配管側の開口部の外
縁部の一部とが互いに密接するように、上記プラグ側の
外周部の一部もしくは上記配管側の開口部の外縁部の一
部に突起部を形成して、上記プラグを捩込み、上記配管
との接触部を密接させることにより溶接部のルートギャ
ップの形成を抑止して、上記プラグを上記配管にすみ肉
溶接した溶接構造とするものである。Further, after screwing a screw-in test plug made of a ferritic high-strength heat-resistant steel containing Nb and V as alloy elements into a set portion on the outer surface of the pipe, the plug is removed. A welded structure for meat welding,
A part of the outer periphery of the plug or the outer periphery of the opening on the pipe side so that a part of the outer periphery on the plug side and a part of the outer edge of the opening on the pipe side are in close contact with each other. A projection is formed in a part, the plug is screwed in, the contact portion with the pipe is brought into close contact to suppress the formation of a root gap in the welded portion, and the plug is fillet-welded to the pipe. It has a structure.
【００１３】また、請求項３において、Ｎｂ、Ｖを合金
元素として含有するフェライト系高強度耐熱鋼よりなる
捩込み式検査プラグを、配管外面の設定の部位に捩込ん
だ後、上記プラグをすみ肉溶接する溶接構造であって、
上記プラグ側の外周部の一部と上記配管側の開口部の外
縁部の一部とが互いに密接するようにテーパー部を形成
して、上記プラグを捩込み、上記配管との接触部を密接
させることにより溶接部のルートギャップの形成を抑止
して、上記プラグを上記配管にすみ肉溶接したすみ肉溶
接構造とするものである。According to the third aspect of the present invention, a screw-in test plug made of a ferritic high-strength heat-resistant steel containing Nb and V as alloy elements is screwed into a set portion on the outer surface of the pipe, and then the plug is removed. A welded structure for meat welding,
A tapered portion is formed so that a part of the outer peripheral portion on the plug side and a part of the outer edge portion of the opening on the pipe side are in close contact with each other, and the plug is screwed in so that a contact portion with the pipe is in close contact. By doing so, the formation of a root gap at the welded portion is suppressed, and a fillet welding structure is formed in which the plug is fillet welded to the pipe.
【００１４】また、請求項４に記載のように、請求項１
ないし３のいずれか１項に記載のすみ肉溶接構造におい
て、上記プラグ材料は、Ｎｂ、Ｖの合金元素を含有せ
ず、かつ上記配管材料よりも引張強度の低いフェライト
系耐熱鋼を用いたすみ肉溶接構造とするものである。Further, as described in claim 4, claim 1
4. The fillet welded structure according to any one of items 3 to 3, wherein the plug material does not contain alloying elements of Nb and V and uses a ferritic heat-resistant steel having a lower tensile strength than the piping material. It has a meat welding structure.
【００１５】また、請求項５に記載のように、請求項１
ないし３のいずれか１項に記載のすみ肉溶接構造におい
て、溶接材料としては、配管材料もしくはプラグ材料よ
りも引張強度の低いフェライト系耐熱鋼よりなる溶接材
料を用いたすみ肉溶接構造とするものである。[0015] Further, as described in claim 5, claim 1 is as follows.
4. The fillet welded structure according to any one of items 3 to 3, wherein the welded material has a fillet welded structure using a ferrite-based heat-resistant steel having a lower tensile strength than a piping material or a plug material. It is.
【００１６】上記請求項１〜５に記載の本発明のすみ肉
溶接構造とすることにより、ＳＲ割れが発生しやすいと
いう従来の問題点を解消することができ、溶接欠陥に対
する信頼性を大きく改善することができる。By using the fillet welding structure of the present invention according to the first to fifth aspects, it is possible to solve the conventional problem that SR cracks easily occur, and to greatly improve the reliability against welding defects. can do.
【００１７】本発明のすみ肉溶接構造は、母管（配管）
とプラグとの接触部を工夫してルートギャップを無く
し、すみ肉溶接を行うものである。また、プラグ材料あ
るいは溶接材料として、ＮｂやＶを含有しない母管より
低強度のものを用いることによって、残留応力の低減が
可能となり、割れの発生の防止に対して、より確実な割
れの抑止効果があげられる。[0017] The fillet welded structure of the present invention comprises a main pipe (piping).
The root gap is eliminated by devising the contact portion between the plug and the plug, and the fillet welding is performed. Further, by using a plug material or a welding material having a lower strength than the mother tube containing no Nb or V, it is possible to reduce the residual stress, and to prevent the occurrence of cracks, it is possible to prevent cracks more reliably. Effective.
【００１８】また、溶接時のプラグの変形を小さく抑え
られるので残留応力が低減でき、また、プラグ材料や溶
接金属の割れ感受性を低くすることができるので、割れ
の発生を抑止することができる。Further, since the deformation of the plug at the time of welding can be suppressed to a small value, the residual stress can be reduced, and the susceptibility of the plug material or the weld metal to cracking can be reduced, so that the occurrence of cracking can be suppressed.
【００１９】本発明のＮｂ、Ｖを合金元素として含有す
るフェライト系高強度耐熱鋼よりなるプラグ材料は、Ｎ
ｂ、Ｖ等を添加したＣｒ含有量が１〜２.２５重量％の
Ｃｒフェライト系高強度耐熱鋼、あるいはＣｒ含有量が
１〜２.２５重量％のＣｒ−Ｍｏフェライト系高強度耐
熱鋼等を用いることができ、これらの高強度フェライト
系耐熱鋼は、Ｎｂ、Ｖ等を添加し、焼ならし−焼戻し熱
処理によって、焼戻しベイナイト組織となるように成分
設計されたものであって、従来材に比べて格段に優れた
高温強度を有するものである。The plug material made of a ferritic high-strength heat-resistant steel containing Nb and V as alloy elements according to the present invention is made of N
Cr-rich ferritic high-strength heat-resistant steel with a Cr content of 1 to 2.25% by weight or Cr-Mo ferrite-type high-strength heat-resistant steel with a Cr content of 1 to 2.25% by weight These high-strength ferritic heat-resistant steels are components designed to have a tempered bainite structure by a normalizing-tempering heat treatment to which Nb, V, etc. are added. It has much higher temperature strength than that of
【００２０】[0020]
【発明の実施の形態】〈実施の形態１〉以下に本発明の
実施の形態の一例を挙げ、本発明のプラグのすみ肉溶接
構造について詳細に説明する。なお、以下に示す実施の
形態１〜４は、プラグ材料としてＮｂ、Ｖ等を合金元素
として含有するフェライト系高強度耐熱鋼を用い、母管
と検査プラグの溶接構造を改良したものであり、実施の
形態５〜６は、Ｎｂ、Ｖ等を含有しない母管より低強度
のフェライト系耐熱鋼よりなるプラグ材料あるいは溶接
材料を用いた場合を示す。BEST MODE FOR CARRYING OUT THE INVENTION <Embodiment 1> An example of an embodiment of the present invention will be described below, and a plug fillet welding structure of the present invention will be described in detail. Embodiments 1 to 4 described below use a ferrite-based high-strength heat-resistant steel containing Nb, V, or the like as an alloy element as a plug material, and improve a welding structure between a mother pipe and an inspection plug. Embodiments 5 and 6 show the case where a plug material or a welding material made of heat-resistant ferritic steel having a lower strength than a mother tube containing no Nb, V, or the like is used.
【００２１】図１は、母管１とプラグ３の取り付け部の
断面構造を示す模式図である。母管１およびプラグ３
は、図６で示した従来構造と同様のネジ加工を施してあ
るが、母管１の開口部の外縁部でプラグ３と接する部分
に座状の嵌合部８を設けたことが特徴である。FIG. 1 is a schematic diagram showing a cross-sectional structure of a mounting portion of the mother pipe 1 and the plug 3. Main pipe 1 and plug 3
Has the same threading as the conventional structure shown in FIG. 6, but is characterized in that a seat-shaped fitting portion 8 is provided at a portion in contact with the plug 3 at the outer edge of the opening of the mother pipe 1. is there.
【００２２】図１はプラグ３を母管１に捩込んで締めた
後の状態であるが、溶接ルート部６では母管１とプラグ
３が隙間なく嵌合しているため溶接ルート部６のギャッ
プは、ほぼ０（零）となる。プラグ３の周囲を、すみ肉
溶接した後の断面図を図２に示す。プラグ３と母管１は
嵌合部８で接しているため、図６で示したプラグ３の変
形が抑えられ、その結果として溶接部に作用する残留応
力が低減される。本実施の形態は、ネジがストレートネ
ジの場合に好適に用いられる。FIG. 1 shows a state after the plug 3 is screwed into the mother pipe 1 and tightened. Since the mother pipe 1 and the plug 3 are fitted with no gap in the welding root part 6, the welding root part 6 The gap is almost 0 (zero). FIG. 2 shows a cross-sectional view of the periphery of the plug 3 after the fillet welding. Since the plug 3 and the mother pipe 1 are in contact with each other at the fitting portion 8, deformation of the plug 3 shown in FIG. 6 is suppressed, and as a result, residual stress acting on the welded portion is reduced. This embodiment is suitably used when the screw is a straight screw.
【００２３】〈実施の形態２〉図３は、本発明の他の実
施の形態のすみ肉溶接構造を示す。本実施の形態の基本
的を考え方と作用は、実施の形態１と同様であるが、実
施の形態１のテーパネジの場合は、ネジ部と嵌合部の相
対的な寸法加工精度に注意を要するのに対し、本実施の
形態では、テーパネジの場合であっても容易に適用でき
る形態を示す。図３において、ネジ部４はテーパネジで
あり、プラグ３のネジ部より先端（上部）は平行な円筒
となっている。母管１の開口部の外縁部に沿って突起部
９を設け、該突起部９の内径がプラグ３の平行部外周と
ほぼ等しくなるようにしてある。この場合も、ルートギ
ャップがほぼ０となるので実施の形態１と同様の効果が
得られる。もちろん、ストレートネジの場合にも適用で
きる。Embodiment 2 FIG. 3 shows a fillet welding structure according to another embodiment of the present invention. Although the basic concept and operation of this embodiment are the same as those of the first embodiment, in the case of the tapered screw of the first embodiment, attention must be paid to the relative dimensional machining accuracy of the screw portion and the fitting portion. On the other hand, the present embodiment shows a mode that can be easily applied even in the case of a tapered screw. In FIG. 3, the screw portion 4 is a tapered screw, and the tip (upper portion) of the screw portion of the plug 3 is a parallel cylinder. A projection 9 is provided along the outer edge of the opening of the mother tube 1, and the inner diameter of the projection 9 is substantially equal to the outer periphery of the parallel portion of the plug 3. In this case, too, the root gap becomes substantially zero, so that the same effect as in the first embodiment can be obtained. Of course, it can be applied to the case of a straight screw.
【００２４】〈実施の形態３〉図４は、本発明の他の実
施の形態のすみ肉溶接構造を示す。本実施の形態は基本
的には実施の形態２と同様であるが、突起部９を母管１
側ではなく、プラグ３側に設けた場合である。この場
合、作用は実施の形態２と同様であるが、定期点検時の
プラグ取り付けおよび取り外し作業（溶接金属５を削
り、点検後に再度すみ肉溶接）を繰り返し行って突起部
９が損耗しても、プラグ３を新しい物に交換すれば、母
管１はそのままで初期と同じ効果が得られる。本実施の
形態は、頻繁に点検を行う部位に好適である。Embodiment 3 FIG. 4 shows a fillet welding structure according to another embodiment of the present invention. This embodiment is basically the same as the second embodiment, except that the projection 9 is
This is a case where it is provided on the plug 3 side, not on the side. In this case, the operation is the same as that of the second embodiment. However, even when the plug attachment and detachment work (sharpening the weld metal 5 and refilling the fillet after the inspection) is repeated during the periodic inspection, the projection 9 is worn. If the plug 3 is replaced with a new one, the same effect as in the initial stage can be obtained without changing the mother tube 1. The present embodiment is suitable for a part that is frequently inspected.
【００２５】〈実施の形態４〉図５は、本発明の他の実
施の形態のすみ肉溶接構造を示す。本実施の形態の基本
的な考え方と作用は実施の形態１と同様であるが、母管
１の開口部の外縁部およぴプラグ３の外周部にテーパ部
１０を設け、互いに接触する構造としたものである。こ
の場合、プラグ３をネジ込んで強く締め付けることによ
り、母管１とプラグ３の接触がより確実になり、接触端
部、すなわち溶接ルート部６に圧縮応力が生じるので、
溶接による残留応力の低減にも効果がある。<Embodiment 4> FIG. 5 shows a fillet welding structure according to another embodiment of the present invention. The basic concept and operation of this embodiment are the same as those of the first embodiment, except that a tapered portion 10 is provided on the outer edge of the opening of the mother tube 1 and on the outer periphery of the plug 3 so that they come into contact with each other. It is what it was. In this case, since the plug 3 is screwed in and tightened strongly, the contact between the mother pipe 1 and the plug 3 becomes more reliable, and a compressive stress is generated at the contact end, that is, the welding root 6.
It is also effective in reducing residual stress due to welding.
【００２６】〈実施の形態５〉上述した実施の形態１〜
４は、母管とプラグ材の構造を工夫したものであるが、
構造は従来のままで、割れ発生のポテンシャルが高いプ
ラグ３の材質を、Ｎｂ、Ｖ等を添加元素として含有しな
い、母管より低強度の材料とする。材質的に割れ感受性
を低減するもので、この場合は既設プラントの従来構造
のプラグであっても割れ発生防止の効果が得られる。ま
た、上記実施の形態１〜４の構造と、上記プラグの材質
とを組み合わせれば、よりいっそう優れた効果が得られ
る。<Embodiment 5> Embodiments 1 to 5 described above.
No. 4 is devised for the structure of the mother tube and plug material.
The structure of the plug 3 having a high potential for crack generation is the same as that of the conventional structure, and the material of the plug 3 does not contain Nb, V, or the like as an additional element and has a lower strength than the mother tube. The material is to reduce the cracking susceptibility. In this case, even if the plug has a conventional structure in an existing plant, the effect of preventing cracking can be obtained. Further, when the structures of the first to fourth embodiments are combined with the material of the plug, more excellent effects can be obtained.
【００２７】〈実施の形態６〉上記実施の形態１〜４
は、母管とプラグ材の構造を工夫したものであるが、構
造と母管およびプラグの材質は従来のままで、溶接材料
にＮｂ、Ｖを添加元素として含有しない母管よりも低強
度の材料を用いる。また、ＳＲ過程において溶接金属の
応力緩和が大きいため、プラグ側の残留応力を低減する
ことができ、割れ発生防止に大きな効果が得られる。ま
た、実施の形態１〜４の構造と組み合わせれば、よりい
っそう優れた効果が得られる。Embodiment 6 Embodiments 1 to 4 above
Is a device in which the structure of the mother pipe and the plug material is devised. However, the structure, the material of the mother pipe and the plug remain unchanged, and the welding material has a lower strength than the mother pipe which does not contain Nb and V as additional elements. Use materials. Further, since the stress relaxation of the weld metal is large in the SR process, the residual stress on the plug side can be reduced, and a great effect can be obtained in preventing cracking. Further, when combined with the structures of Embodiments 1 to 4, more excellent effects can be obtained.
【００２８】[0028]
【発明の効果】本発明のすみ肉溶接構造によれば、Ｎ
ｂ、Ｖ等を合金元素として含み、１〜２.２５重量％Ｃ
ｒフェライト系高強度耐熱鋼、またはＮｂ、Ｖ等を合金
元素として含み、１〜２.２５重量％Ｃｒ−Ｍｏフェラ
イト系高強度耐熱鋼等よりなる検査プラグのすみ肉溶接
構造とすることが可能となり、ＳＲ割れが発生しやすい
という従来の問題点を解消することができ、溶接欠陥に
対する信頼性を大きく改善することができる。According to the fillet welded structure of the present invention, N
b, V, etc. as alloying elements, 1-2.25% by weight C
r Fillet welded structure of test plugs made of ferritic high-strength heat-resistant steel or 1-25 wt% Cr-Mo ferritic high-strength heat-resistant steel containing Nb, V, etc. as alloying elements Thus, the conventional problem that SR cracks easily occur can be solved, and the reliability against welding defects can be greatly improved.
【００２９】また、母管より低強度のフェライト系耐熱
鋼よりなるプラグ材料あるいは溶接材料を用いることに
よっても、残留応力の低減が可能となり、ＳＲ割れの発
生を防止することができ、溶接欠陥に対する信頼性を向
上することができる。Also, by using a plug material or a welding material made of ferritic heat-resistant steel having a lower strength than the mother pipe, the residual stress can be reduced, SR cracks can be prevented, and welding defects can be reduced. Reliability can be improved.
【図１】本発明の実施の形態１で例示したプラグの構造
を示す模式図。FIG. 1 is a schematic diagram showing a structure of a plug exemplified in Embodiment 1 of the present invention.
【図２】本発明の実施の形態１で例示したプラグのすみ
肉溶接後の状況を示す模式図。FIG. 2 is a schematic view showing a situation after fillet welding of the plug exemplified in the first embodiment of the present invention.
【図３】本発明の実施の形態２で例示したプラグの構造
を示す模式図。FIG. 3 is a schematic diagram showing the structure of a plug exemplified in Embodiment 2 of the present invention.
【図４】本発明の実施の形態３で例示したプラグの構造
を示す模式図。FIG. 4 is a schematic diagram showing a structure of a plug exemplified in a third embodiment of the present invention.
【図５】本発明の実施の形態４で例示したプラグの構造
を示す模式図。FIG. 5 is a schematic view showing a structure of a plug exemplified in a fourth embodiment of the present invention.
【図６】従来の配管およびプラグの取付け構造を示す模
式図。FIG. 6 is a schematic view showing a conventional pipe and plug mounting structure.
【図７】従来のプラグの構造を示す模式図。FIG. 7 is a schematic view showing the structure of a conventional plug.
【図８】従来のプラグのすみ肉溶接後の状況を示す模式
図。FIG. 8 is a schematic view showing a situation after fillet welding of a conventional plug.
１…母管 ２…周溶接部 ３…プラグ ４…ネジ部 ５…溶接金属 ６…溶接ルート部 ７…亀裂 ８…嵌合部 ９…突起部 １０…テーパ部 １１…ギャップ DESCRIPTION OF SYMBOLS 1 ... Base pipe 2 ... Perimeter weld part 3 ... Plug 4 ... Screw part 5 ... Weld metal 6 ... Weld root part 7 ... Crack 8 ... Fitting part 9 ... Projection part 10 ... Taper part 11 ... Gap
Claims (5)
フェライト系耐熱鋼よりなる捩込み式検査プラグを、配
管外面の設定の部位に捩込んだ後、上記プラグをすみ肉
溶接する溶接構造であって、上記プラグ側の外周部の一
部が、上記配管側の開口部の外縁部と密接して嵌合する
上記プラグの座を設け、該座に、上記プラグを捩込み、
上記配管との接触部を密接させることにより溶接部のル
ートギャップの形成を抑止して、上記プラグを上記配管
にすみ肉溶接してなることを特徴とするすみ肉溶接構
造。1. A welding structure in which a screw-in test plug made of high-strength ferritic heat-resistant steel containing Nb and V as an alloy element is screwed into a set portion on the outer surface of a pipe, and then the plug is fillet-welded. A part of the outer peripheral portion on the plug side is provided with a seat for the plug that fits closely with the outer edge of the opening on the pipe side, and the plug is screwed into the seat;
A fillet welding structure, wherein the plug is welded to the pipe by fillet welding by suppressing the formation of a root gap at the welded portion by bringing the contact portion into close contact with the pipe.
フェライト系耐熱鋼よりなる捩込み式検査プラグを、配
管外面の設定の部位に捩込んだ後、上記プラグをすみ肉
溶接する溶接構造であって、上記プラグ側の外周部の一
部と上記配管側の開口部の外縁部の一部とが互いに密接
するように、上記プラグ側の外周部の一部もしくは上記
配管側の開口部の外縁部の一部に突起部を形成して、上
記プラグを捩込み、上記配管との接触部を密接させるこ
とにより溶接部のルートギャップの形成を抑止して、上
記プラグを上記配管にすみ肉溶接してなることを特徴と
するすみ肉溶接構造。2. A welding structure in which a screw-in test plug made of a high-strength ferritic heat-resistant steel containing Nb and V as an alloy element is screwed into a set portion on the outer surface of a pipe, and then the plug is fillet-welded. A part of the outer periphery of the plug or the opening of the piping so that a part of the outer periphery of the plug and a part of the outer edge of the opening of the piping are in close contact with each other. A projection is formed on a part of the outer edge of the plug, and the plug is screwed in so that a contact portion with the pipe is brought into close contact to suppress the formation of a root gap at a welded portion. Fillet welding structure characterized by meat welding.
フェライト系耐熱鋼よりなる捩込み式検査プラグを、配
管外面の設定の部位に捩込んだ後、上記プラグをすみ肉
溶接する溶接構造であって、上記プラグ側の外周部の一
部と上記配管側の開口部の外縁部の一部とが互いに密接
するようにテーパー部を形成して、上記プラグを捩込
み、上記配管との接触部を密接させることにより溶接部
のルートギャップの形成を抑止して、上記プラグを上記
配管にすみ肉溶接してなることを特徴とするすみ肉溶接
構造。3. A welding structure in which a screw-in test plug made of a high-strength ferritic heat-resistant steel containing Nb and V as an alloy element is screwed into a set portion on the outer surface of a pipe, and the plug is fillet-welded. And forming a tapered portion so that a part of the outer peripheral part on the plug side and a part of the outer edge part of the opening on the pipe side are in close contact with each other, screw the plug in, and A fillet welding structure, wherein the plug is welded to the pipe by fillet welding by suppressing the formation of a root gap at the welded portion by bringing the contact portions into close contact.
すみ肉溶接構造において、上記プラグ材料は、Ｎｂ、Ｖ
の合金元素を含有せず、かつ上記配管材料よりも引張強
度の低いフェライト系耐熱鋼を用いることを特徴とする
すみ肉溶接構造。4. The fillet welded structure according to claim 1, wherein said plug material comprises Nb, V
A fillet welded structure using a ferritic heat-resistant steel that does not contain the alloy element of (1) and has a lower tensile strength than the piping material.
すみ肉溶接構造において、溶接材料としては、配管材料
もしくはプラグ材料よりも引張強度の低いフェライト系
耐熱鋼よりなる溶接材料を用いることを特徴とするすみ
肉溶接構造。5. The fillet welded structure according to claim 1, wherein the welding material is a welding material made of ferritic heat-resistant steel having a lower tensile strength than a piping material or a plug material. A fillet welded structure characterized by the following.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000309336A JP2002113576A (en) | 2000-10-10 | 2000-10-10 | Fillet welding structure |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000309336A JP2002113576A (en) | 2000-10-10 | 2000-10-10 | Fillet welding structure |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2002113576A true JP2002113576A (en) | 2002-04-16 |
Family
ID=18789522
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2000309336A Pending JP2002113576A (en) | 2000-10-10 | 2000-10-10 | Fillet welding structure |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2002113576A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011173139A (en) * | 2010-02-23 | 2011-09-08 | Mitsubishi Heavy Ind Ltd | Plug structure of inspection hole |
| WO2018036534A1 (en) * | 2016-08-25 | 2018-03-01 | 北京文源同创科技有限公司 | Welding machine |
| WO2021157163A1 (en) * | 2020-02-07 | 2021-08-12 | 三菱パワー株式会社 | Plug, steam pipe structure, and method for installing plug |
-
2000
- 2000-10-10 JP JP2000309336A patent/JP2002113576A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011173139A (en) * | 2010-02-23 | 2011-09-08 | Mitsubishi Heavy Ind Ltd | Plug structure of inspection hole |
| WO2018036534A1 (en) * | 2016-08-25 | 2018-03-01 | 北京文源同创科技有限公司 | Welding machine |
| WO2021157163A1 (en) * | 2020-02-07 | 2021-08-12 | 三菱パワー株式会社 | Plug, steam pipe structure, and method for installing plug |
| JP2021122851A (en) * | 2020-02-07 | 2021-08-30 | 三菱パワー株式会社 | Plug, steam pipe structure and plug installation method |
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