JPH0794070B2 - Welding method for chrome-molybdenum steel - Google Patents
Welding method for chrome-molybdenum steelInfo
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- JPH0794070B2 JPH0794070B2 JP30383886A JP30383886A JPH0794070B2 JP H0794070 B2 JPH0794070 B2 JP H0794070B2 JP 30383886 A JP30383886 A JP 30383886A JP 30383886 A JP30383886 A JP 30383886A JP H0794070 B2 JPH0794070 B2 JP H0794070B2
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Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明はクロム−モリブデン（Cr−Mo）鋼の溶接方法に
係り，特に機器構成部材の溶接もしくは補修溶接におい
て，溶接により生ずる軟化部を，溶接した部材の応力集
中部より離れた位置に移動させることによって機器の破
壊を防止するCr−Mo鋼の溶接方法および溶接後の熱処理
方法に関する。Description: TECHNICAL FIELD The present invention relates to a welding method for chrome-molybdenum (Cr—Mo) steel, and in particular, in welding or repair welding of component parts of a device, a softened portion caused by welding, TECHNICAL FIELD The present invention relates to a welding method for Cr-Mo steel and a heat treatment method after welding, in which the destruction of equipment is prevented by moving a welded member to a position away from a stress concentration portion.
火力発電プラントあるいは化学装置などの高温，高圧で
使用される機器材料としてはCrとMoを添加した耐熱性の
Cr−Mo鋼が使用されている。この理由は,CrおよびMo添
加による析出強化および固溶強化によって強度が向上す
ること，さらに緻密なCr酸化物の形成により耐酸化性が
向上するためである。現在使用されているCr−Mo鋼のCr
含有量は2.25重量（wt）％以下のものが大部分である。
しかし，オーステナイト系ステンレス鋼と比較すると高
温強度，耐酸化性が大幅に劣ることから，さらにCr含有
量を８〜13重量％に増大させると共に，焼ならし後，焼
もどし処理を行うことによって焼もどしてルテンサイト
あるいは焼もどしベーナイト組織となるように調質して
高温強度と耐酸化性を向上させたCr−Mo鋼が開発され，
その一部はオーステナイト系ステンレス鋼の代替材料と
して実用化されている。As a material for equipment used at high temperature and high pressure in thermal power plants or chemical equipment, heat resistant materials containing Cr and Mo are used.
Cr-Mo steel is used. The reason for this is that the strength is improved by precipitation strengthening and solid solution strengthening by adding Cr and Mo, and further the oxidation resistance is improved by forming a dense Cr oxide. Cr of Cr-Mo steel currently used
Most of the content is 2.25 wt% or less.
However, compared with austenitic stainless steel, its high-temperature strength and oxidation resistance are significantly inferior. Therefore, the Cr content is further increased to 8 to 13% by weight and, after normalizing, tempering is performed. A Cr-Mo steel has been developed that has been tempered so as to have a lutensite or tempered bainite structure and improved high temperature strength and oxidation resistance.
Some of them have been put to practical use as substitute materials for austenitic stainless steel.
このようなCr−Mo鋼の特性を調査したところ，溶接や熱
間曲げ加工に伴う加熱によって特定の温度範囲に加熱さ
れた領域が軟化し，強度低下を生ずることが明らかにな
った。第３図は,9（wt）％Cr−１（wt）％Mo鋼の管（45
mmφ×10mmt）を，初層をガス・タングステン・アーク
溶接（GTAW）,2層以降をシールドメタル・アーク溶接
（SMAW）法によって周溶接し（予熱:200℃，入熱:20kJ/
cm,後熱処理:740℃×1h），その継手から外径6mm,長さ3
0mmの試験片を採取し，単軸クリープ破断テストを行っ
た結果である。継手のクリープ破断強度は，母材に比べ
低下し，破断位置は溶接熱影響部最外層であった。第４
図は，この継手のビッカース硬さ（Hv）分布を示したも
のであるが，溶接熱影響部最外層で軟化しており，破断
位置と対応している。さらに詳細に検討すると，軟化す
る部分は溶接や熱間曲げ加工によりA3変態点（フェライ
トからオーステナイトへの変態が完了する温度，この材
料では870〜890℃）直上に加熱され，結晶粒が微細化し
た部分が溶接後の熱処理により軟化することが分かっ
た。この対策として，本発明者らは先に，変態点以上の
局部加熱を伴う溶接や熱間曲げ加工が実施されるCr−Mo
鋼において，焼ならし後の焼もどし処理温度を，使用す
る材料のA1変態点（フェライトからオーステナイトへの
変態を開始する温度）よりも150℃低い温度以下として
焼きもどし処理を行い，溶接あるいは熱間曲げ加工を行
った後、A1変態点よりも100℃低い温度以上で後熱処理
することにより，軟化部の発生を防止するCr−Mo鋼の熱
処理法の発明を出願している（特願昭61−134948号）。When the properties of such Cr-Mo steel were investigated, it became clear that the region heated to a specific temperature range softened due to heating associated with welding and hot bending, resulting in a decrease in strength. Figure 3 shows a tube of 9 (wt)% Cr-1 (wt)% Mo steel (45
mmφ × 10 mmt), the first layer is gas-tungsten-arc welding (GTAW), and the second and subsequent layers are circumferentially welded by the shield metal arc welding (SMAW) method (preheat: 200 ° C, heat input: 20 kJ /
cm, post heat treatment: 740 ℃ × 1h), outer diameter 6mm from the joint, length 3
This is the result of a uniaxial creep rupture test of a 0 mm test piece. The creep rupture strength of the joint was lower than that of the base metal, and the fracture position was in the outermost layer of the weld heat affected zone. Fourth
The figure shows the Vickers hardness (Hv) distribution of this joint, which is softened in the outermost layer of the heat affected zone and corresponds to the fracture position. A closer examination shows that the softened part is heated immediately above the A 3 transformation point (the temperature at which the transformation from ferrite to austenite is completed, 870 to 890 ° C in this material) by welding or hot bending, and the crystal grains become fine. It was found that the converted portion was softened by the heat treatment after welding. As measures against this, the present inventors have previously performed Cr-Mo in which welding or hot bending with local heating above the transformation point is performed.
In steel, the tempering treatment after normalizing is performed at a temperature 150 ° C lower than the A 1 transformation point (temperature at which transformation from ferrite to austenite starts) of the material used, and then the welding or welding is performed. We have applied for an invention of a heat treatment method for Cr-Mo steel that prevents the occurrence of softened parts by performing post heat treatment at a temperature 100 ° C lower than the A 1 transformation point after hot bending ( No. 61-134948).
上述した本発明者らの出願にかかるCr−Mo鋼の熱処理法
の発明は，新規に火力発電プラントや化学装置を製作す
る場合に非常に有効な方法であるが，これには，製作組
立後の欠陥補修のための補修溶接についての配慮がなさ
れていなかった。すなわち，上記発明の要点は母材の焼
もどし温度を低くして溶接後の熱処理温度を高くするこ
とにあるが，これらのプラントの製作，組立の時点で
は，すでに溶接部，熱間曲げ加工部を含む全体を高い温
度で後熱処理しており，補修溶接を実施するとA3変態点
直上に加熱される部分が発生し，後熱処理により軟化す
る。これは，補修溶接では不可避のものである。しか
も，補修溶接を実施する箇所はボイラでいえば過熱器管
寄と主蒸気配管のＴ継手溶接部のような不連続部で，し
かも応力が集中する部分であり，補修溶接によって発生
した軟化部は非常に危険である。The invention of the heat treatment method for Cr—Mo steel according to the application of the present inventors as described above is a very effective method when a new thermal power plant or a chemical device is manufactured. No consideration was given to repair welding for repairing defects. That is, the point of the above invention is to lower the tempering temperature of the base material and raise the heat treatment temperature after welding. However, at the time of manufacturing and assembling these plants, the welded portion and hot-bent portion were already welded. The entire part including is subjected to post heat treatment at a high temperature, and when repair welding is performed, a portion that is heated immediately above the A 3 transformation point is generated, and the post heat treatment softens. This is inevitable in repair welding. Moreover, the place where the repair welding is performed is a discontinuous part such as the T-joint weld part of the superheater pipe side and the main steam pipe in the boiler, where stress is concentrated, and the softening part generated by the repair welding. Is very dangerous.
本発明の目的は，火力発電プラントや化学装置などの高
温，高圧で使用される機器の構成部材であるCr−Mo鋼の
溶接もしくは補修溶接において，不可避に発生する軟化
部を，溶接した部材の応力集中部以外の安全な位置に移
動させて，機器の損傷の防止をはかる溶接方法ならびに
溶接後の熱処理方法を提供することにある。An object of the present invention is to weld a softened portion that is inevitably generated in welding or repair welding of Cr-Mo steel, which is a constituent member of equipment used at high temperature and high pressure such as a thermal power plant and a chemical device. It is an object of the present invention to provide a welding method and a heat treatment method after welding by moving to a safe position other than the stress concentration part to prevent damage to equipment.
上記本発明の目的は,Cr−Mo鋼よりなる部材の溶接もし
くは補修溶接において，溶接後に溶接部近傍の焼ならし
および焼もどし熱処理を行い，かつ上記の熱処理範囲
を，溶接によって生ずる軟化部の位置が，部材の応力集
中部の位置よりも十分に離れた位置に移動する範囲とす
ることにより，達成される。The above-mentioned object of the present invention is, in welding or repair welding of a member made of Cr-Mo steel, performing normalizing and tempering heat treatment in the vicinity of the welded portion after welding, and setting the above heat treatment range to the softened portion caused by welding. This is achieved by setting the range so that the position moves to a position sufficiently distant from the position of the stress concentration part of the member.
さらに本発明の目的は,Cr−Mo鋼よりなる部材を，焼な
らし処理した後，溶接を行ない，ついで焼もどし処理を
行うことによっても，達成される。Further, the object of the present invention can also be achieved by subjecting a member made of Cr-Mo steel to normalizing treatment, welding, and then tempering treatment.
本発明の対象となるCr−Mo鋼は，例えばJISボイラ用鋼
管材として規格化されているSTB42B（Cr0.8〜1.2重量
％,Mo0.2〜0.45重量％）,STB42C（Cr0.8〜1.2,Mo0.45〜
0.65）,STB42D（Cr2〜2.5,Mo0.9〜1.1）,STB42E（Cr4〜
6,Mo0.45〜0.65）,STB42G（Cr1〜1.5,Mo0.45〜0.65）,S
TB42H（Cr8〜10,Mo0.9〜1.1）など，およびCrの含有量
が８〜13％程度含むCr−Mo鋼よりなる管材，板材もしく
はその他の形状をした部材を挙げることができる。The Cr-Mo steel to be the subject of the present invention is, for example, STB42B (Cr 0.8 to 1.2% by weight, Mo 0.2 to 0.45% by weight), STB42C (Cr 0.8 to 1.2% by weight) that is standardized as a JIS boiler steel pipe material. , Mo0.45〜
0.65), STB42D (Cr2 ~ 2.5, Mo0.9 ~ 1.1), STB42E (Cr4 ~
6, Mo0.45 ~ 0.65), STB42G (Cr1 ~ 1.5, Mo0.45 ~ 0.65), S
Examples include TB42H (Cr8-10, Mo0.9-1.1) and the like, and a tube material, plate material or other shaped member made of Cr-Mo steel having a Cr content of about 8-13%.
本発明の溶接もしくは補修溶接後に行う熱処理は,Co−M
o鋼のA3変態点からA3変態点＋50℃の温度範囲に加熱す
る焼ならし処理後，焼もどし処理を行うことにより達成
される。The heat treatment performed after welding or repair welding of the present invention is Co-M.
After normalizing process from A 3 transformation point o steel is heated to a temperature range of A 3 transformation point + 50 ° C., it is achieved by performing the tempering treatment.
本発明のCr−Mo鋼よりなる部材の溶接もしくは補修溶接
において，溶接により生ずる軟化部の位置を応力集中部
の位置より十分に離れた位置に移動させるためには，溶
接後に行う熱処理の範囲を，おおよそCr−Mo鋼よりなる
部材の厚さ以上，その厚さの10倍以下の範囲とすること
が好ましい。In welding or repair welding of a member made of the Cr-Mo steel of the present invention, in order to move the position of the softened portion caused by welding to a position sufficiently distant from the position of the stress concentration portion, the range of heat treatment performed after welding is It is preferable that the thickness of the member is approximately equal to or more than the thickness of the Cr-Mo steel member and less than or equal to 10 times the thickness.
また，本発明のCr−Mo鋼よりなる部材の溶接もしくは補
修溶接において，溶接により生ずる軟化部の位置を応力
集中部の位置より十分に離れた位置に移動させるために
は，溶接後に行う熱処理の範囲を，溶接止端部もしくは
補修溶接前の溶接止端部から少なくとも10mm以上離れた
範囲とすることによっても本発明の目的を達成すること
ができる。Further, in welding or repair welding of a member made of the Cr-Mo steel of the present invention, in order to move the position of the softened portion caused by welding to a position sufficiently distant from the position of the stress concentration portion, heat treatment performed after welding is performed. The object of the present invention can also be achieved by setting the range at least 10 mm or more from the weld toe or the weld toe before repair welding.
Cr−Mo鋼よりなる部材の溶接もしくは補修溶接によって
発生した溶接熱影響部最外層の軟化部は，再度，焼なら
し後焼もどし（焼ならし−焼もどし）処理することによ
って元の特性に回復する。このことから，溶接部もしく
は補修溶接部を含む範囲を焼ならし−焼もどし処理する
ことにより，溶接部の熱影響部最外層の軟化は防止でき
る。しかし，この焼ならし−焼もどし処理により新たに
軟化部が発生する。本発明者らが検討したところ，例え
ばCr−Mo鋼管の周溶接継手で軟化部を有する場合であっ
ても，内圧クリープ破断試験の結果では母材部で破断
し、母材と同等の強度を有することが判明した。すなわ
ち，管の周方向応力のみが作用する場合には，管の軸方
向に対して数mm程度の幅で軟化部を有していても，実用
上ほとんど問題が発生しない。以上のことから，焼なら
し−焼もどし処理により発生す軟化部を，管の周方向応
力のみが作用する位置になるように焼ならし−焼もどし
処理の範囲を拡大し，部材の応力集中部より離れた位置
に移動させることによって溶接によう軟化問題を解決す
ることができる。The softened part of the outermost layer of the weld heat affected zone generated by welding or repair welding of a member made of Cr-Mo steel is restored to its original properties by re-normalizing and tempering (normalizing-tempering). Recover. Therefore, softening of the outermost layer of the heat-affected zone of the weld can be prevented by normalizing and tempering the range including the weld or the repair weld. However, this normalizing-tempering process causes a new softened portion to occur. The present inventors have studied, for example, even in the case of having a softened portion in the circumferential welded joint of Cr-Mo steel pipe, in the result of the internal pressure creep rupture test, it fractures in the base metal portion, and the strength equivalent to that of the base metal is obtained. Turned out to have. That is, when only the circumferential stress of the pipe acts, even if the softened portion has a width of several mm with respect to the axial direction of the pipe, practically no problem occurs. From the above, the range of normalization-tempering treatment is expanded so that the softened part generated by normalization-tempering treatment is located at the position where only the stress in the circumferential direction of the pipe acts, and the stress concentration of the member is concentrated. By moving to a position away from the part, the softening problem like welding can be solved.
また，管と管とのＴ継手溶接部（スタッブ溶接）の場合
には，溶接止端部で最も応力が集中する。このような溶
接部を補修する場合には，補修溶接による熱影響部（後
熱処理による軟化部）が元の溶接止端部近くに位置すれ
ば非常に危険である。そこで，補修溶接時に欠陥を削除
する場合に，元の溶接止端部から十分に離れた位置まで
削除した後，補修溶接を実施することにより，最も危険
な応力集中部と軟化部との距離を十分に離すことができ
る。この方法により，溶接軟化部の影響を十分に排除す
ることができる。In the case of a T-joint welded portion (stub welding) between pipes, the stress is concentrated most at the weld toe. When repairing such welds, it is extremely dangerous if the heat-affected zone of the repair welding (softened zone by post heat treatment) is located near the original weld toe. Therefore, when removing defects during repair welding, the most dangerous distance between the stress-concentrated part and the softened part is removed by performing repair welding after deleting to a position sufficiently far from the original weld toe. Can be well separated. By this method, the influence of the weld softening part can be sufficiently eliminated.
以下に本発明の一実施例を挙げ，図面に基づいてさらに
詳細に説明する。Hereinafter, one embodiment of the present invention will be described in more detail with reference to the drawings.
（実施例１） 第１図は，ボイラの過熱器管寄１と主蒸気配管２とのＴ
継手溶接部３に補修溶接を実施したところを示してい
る。材質は過熱器管寄1,主蒸気配管２とも９（wt）％Cr
−１（wt）％Mo系のCr−Mo鋼であり，補修溶接部４は，
あらかじめグラインダなどで欠陥が削除できるまで削り
こんで，母材と同成分系の溶接材料で補修溶接を実施し
ている。溶接条件の一例を示すと，予熱200℃で電流170
A,電圧20V,溶接速度10cm/minである。溶接終了後，第１
図中の点線で囲んだＡ部を焼ならし−焼もどし処理す
る。この熱処理温度は，材料の製造最終熱処理温度です
れば良く，上記の9Cr−1Mo鋼では焼ならし1040℃×1h,
焼もどし760℃×5hである。なお，焼もどしする範囲は
焼ならしにより発生した熱影響部までする必要があるた
め，焼ならし範囲よりもやや広くする必要がある。した
がって，熱処理範囲はＴ継手溶接部３からそれぞれの管
の板厚以上離れた位置までする必要があり，あまり離れ
すぎると熱処理範囲が広くなり過ぎて，作業性，コスト
などに問題が生ずるため，それぞれの管の板厚の10倍以
上とするのが好ましく，ここでは過熱器管寄１側，主蒸
気配管２側とも約300mmとした。また，加熱方法しては
インダクションヒータを使用した。(Embodiment 1) FIG. 1 shows a T of a boiler superheater pipe side 1 and a main steam pipe 2.
The figure shows the repair welding performed on the joint weld 3. The material is 9 (wt)% Cr for both the superheater pipe 1 and the main steam pipe 2.
-1 (wt)% Mo-based Cr-Mo steel, the repair weld 4 is
Grinding is performed in advance until defects can be removed, and repair welding is performed with a welding material of the same composition as the base metal. An example of welding conditions is as follows: preheating 200 ° C, current 170
A, voltage 20 V, welding speed 10 cm / min. After welding, first
A portion surrounded by a dotted line in the figure is subjected to normalizing-tempering processing. This heat treatment temperature may be the final heat treatment temperature for the production of the material. In the above 9Cr-1Mo steel, normalization is 1040 ℃ × 1h,
Tempering is 760 ℃ x 5h. The tempering range must be a little wider than the normalizing range because it is necessary to extend to the heat-affected zone generated by the normalizing. Therefore, it is necessary to set the heat treatment range to a position separated from the T-joint welded portion 3 by at least the plate thickness of each pipe. It is preferable that the thickness of each pipe is 10 times or more, and here, both the side of the superheater pipe 1 and the side of the main steam pipe 2 are set to about 300 mm. An induction heater was used as the heating method.
補修溶接後，通常の後熱処理を実施すると従来技術でも
述べたように補修溶接部４の熱影響部に軟化部が生じ
る。このような部分で軟化部があると三軸応力状態とな
り，しかもＴ継手溶接部３の溶接止端部で応力が集中し
やすく，非常に危険である。本発明の実施例のようにＡ
部を焼ならし−焼もどし処理すると，補修溶接部４の熱
影響部は焼ならしによりほぼ完全に変態してから焼もど
しされるため，製造時と同等の強度を有するようにな
る。当然,A部全体を焼ならし−焼もどし処理されるた
め，製造時と同等の強度を有するようになる。このよう
な熱処理により,A部の外側に軟化部が生じるが，この位
置では管の内圧による周方向応力のみが作用しており，
本発明者らが検討したところ，軟化部を有していても内
圧クリープでは母材で破断するため実用上問題は発生し
ない。このように，管の周方向応力のみが作用するよう
な位置を検討したところ,T継手部を構成している管の板
厚によって支配され，管の板厚以上離せば，管にはほと
んど周方向応力のみが作用するようになることが分かっ
た。If normal post-heat treatment is carried out after repair welding, a softened portion is generated in the heat-affected zone of the repair welded portion 4 as described in the prior art. If there is a softened portion in such a portion, a triaxial stress state occurs, and furthermore, stress tends to concentrate at the weld toe of the T-joint welded portion 3, which is very dangerous. As in the embodiment of the present invention, A
When the portion is subjected to normalization-tempering treatment, the heat-affected zone of the repaired welded portion 4 is transformed almost completely by normalization and then tempered, so that it has strength equivalent to that during manufacturing. Naturally, the entire A section is subjected to normalizing-tempering processing, so that it has the same strength as during manufacturing. Due to such heat treatment, a softened part is generated on the outside of the A part, but at this position, only the circumferential stress due to the internal pressure of the pipe acts,
As a result of examination by the present inventors, there is no problem in practical use because even if the softened portion is included, internal pressure creep causes fracture in the base material. In this way, when the position where only the stress in the circumferential direction of the pipe acts is examined, it is governed by the plate thickness of the pipe that constitutes the T-joint part. It has been found that only directional stress comes into play.
以上のような補修溶接後の熱処理をすれば，軟化部を溶
接止端部の応力集中部から離すだけでなく，そのまわり
の多軸応力状態の部分からも離すことができ，ほぼ完全
に軟化部の影響を取り除くことができる。If the heat treatment after repair welding as described above is performed, the softened part can be separated not only from the stress concentration part of the weld toe but also from the part in the multiaxial stress state around it, and the softening is almost completely completed. The influence of the department can be removed.
なお，本実施例では補修溶接後，焼ならし−焼もどし処
理をしたが，焼ならし後，補修溶接し，その後，焼もど
し処理をしても同等の効果が得られる。また，補修溶接
に限らず，新規に溶接する場合にも本実施例は適用でき
る。In this embodiment, the normalizing-tempering treatment is performed after the repair welding, but the same effect can be obtained by performing the normalizing treatment, the repair welding, and then the tempering treatment. Further, the present embodiment is applicable not only to repair welding but also to new welding.
（実施例２） 第２図（ａ）のように，過熱器管寄１と主蒸気配管２と
のＴ継手溶接部３に欠陥部５があった場合，第２図
（ｂ）のように欠陥部５を削除して溶接開先を設ける
が，従来は欠陥部５の削除する範囲をできるだけ小さく
している。しかし，本実施例では第２図（ｂ）に示すご
とく削除する範囲を大きくしている。その後，第２図
（ｃ）のように補修溶接を実施して表面を仕上げ，通常
の後熱処理を行う。溶接開先の範囲は元のＴ継手溶接止
端部から少なくとも10mm以上離れた位置まで削除する必
要がある。これは,10mm以下では溶接止端部の応力集中
の影響が生じ,10mm以上ではその影響がほとんどなるな
るからである。以上のような方法によれは，溶接止端部
の応力集中部と，補修溶接によって発生した軟化部との
位置を少なくとも10mm以上離すことができ，最も危険な
応力集中部と軟化部の一致を避けることができる。ま
た，本実施例の方法によると，極めて簡単に溶接軟化部
の影響を排除することができる。(Example 2) As shown in Fig. 2 (a), when there is a defective portion 5 in the T-joint weld 3 between the superheater pipe side 1 and the main steam pipe 2, as shown in Fig. 2 (b). Although the defective portion 5 is deleted and a welding groove is provided, conventionally, the range in which the defective portion 5 is deleted is made as small as possible. However, in this embodiment, the range to be deleted is enlarged as shown in FIG. Then, as shown in FIG. 2 (c), repair welding is performed to finish the surface, and ordinary post heat treatment is performed. The range of the weld groove must be deleted at least 10 mm away from the original T-joint weld toe. This is because the effect of stress concentration at the weld toe occurs when the thickness is 10 mm or less, and the effect becomes almost equal when the thickness is 10 mm or more. According to the above method, the stress-concentrated portion at the weld toe and the softened portion generated by repair welding can be separated by at least 10 mm, and the most dangerous coincidence between the stress-concentrated portion and the softened portion can be achieved. Can be avoided. Further, according to the method of the present embodiment, the influence of the weld softening portion can be eliminated very easily.
以上詳細に説明したごとく，本発明の方法によれば,Cr
−Mo鋼の溶接もしくは補修溶接において発生する軟化部
と応力集中部の位置を，極めて簡便な手法で分離させる
ことができ，軟化部の発生による機器構成部材の破断を
防止することができる。したがって,Cr−Mo鋼によって
製作された火力発電プラントや化学装置などの高温，高
圧で使用される機器の補修溶接に際して，強度低下を起
こすことなく十分に，しかも安価に補修することがで
き，機器の寿命を一段と伸ばすことが可能となる。As described in detail above, according to the method of the present invention, Cr
-The positions of the softening part and stress concentration part that occur during welding or repair welding of Mo steel can be separated by an extremely simple method, and the breakage of the component parts due to the occurrence of the softening part can be prevented. Therefore, during repair welding of equipment used at high temperature and high pressure such as thermal power plants and chemical equipment made of Cr-Mo steel, it can be repaired sufficiently and inexpensively without causing strength deterioration. It is possible to further extend the life of the.
第１図は本発明の実施例１における過熱器管寄と主蒸気
配管のＴ継手を示す説明図，第２図（ａ），（ｂ），
（ｃ）は本発明の実施例２におけるＴ継手の補修溶接方
法の手順を示す説明図，第３図は9Cr−1Mo鋼の継手およ
び母材の単軸クリープ破断特性を示すグラフ，第４図は
第３図における継手の硬さ分布を示すグラフである。 １……過熱器管寄、２……主蒸気配管 ３……Ｔ継手溶接部、４……補修溶接部 ５……欠陥部FIG. 1 is an explanatory view showing a T-joint of a superheater pipe side and a main steam pipe in Embodiment 1 of the present invention, FIGS. 2 (a), (b),
(C) is an explanatory view showing the procedure of the repair welding method for the T-joint in Embodiment 2 of the present invention, FIG. 3 is a graph showing the uniaxial creep rupture characteristics of the joint and base metal of 9Cr-1Mo steel, and FIG. 4 is a graph showing the hardness distribution of the joint in FIG. 1 ... To the superheater pipe, 2 ... Main steam pipe 3 ... T joint weld, 4 ... Repair weld 5 ... Defective part
Claims (6)
部材の溶接方法において，上記部材を溶接した後に溶接
部近傍を焼ならしおよび焼もどしの熱処理を行うか，も
しくは上記部材を焼ならし処理した後に溶接を行い，つ
いで溶接部近傍を焼もどしの熱処理を行う方法であっ
て，上記溶接部近傍の熱処理を行う範囲が，上記溶接し
た部材の溶接熱影響部に生ずる軟化部を，上記溶接した
部材の応力集中部より離れた位置に移動させる範囲であ
ることを特徴とするクロム−モリブデン鋼の溶接方法。1. A method for welding a member made of chrome-molybdenum (Cr-Mo) steel, wherein after the members are welded, heat treatment such as normalizing and tempering is performed in the vicinity of the welded portion, or After the heat treatment, welding is performed, and then heat treatment for tempering the vicinity of the welded portion is performed, and the range of heat treatment in the vicinity of the welded portion is the softened portion generated in the weld heat affected zone of the welded member, A method for welding chromium-molybdenum steel, characterized in that the welded member is moved to a position away from a stress concentration portion.
点からA3変態点プラス50℃の温度範囲に加熱する焼なら
し処理後，焼もどし処理を行うことを特徴とする特許請
求の範囲第１項に記載のクロム−モリブデン鋼の溶接方
法。2. A heat treatment performed after welding, after normalizing process of heating the A 3 transformation point of Cr-Mo steel to a temperature range of A 3 transformation point plus 50 ° C., and performing tempering A method for welding chromium-molybdenum steel according to claim 1.
りなる部材のほぼ厚さ以上，部材の厚さの10倍以下の範
囲とすることを特徴とする特許請求の範囲第１項または
第２項に記載のクロム−モリブデン鋼の溶接方法。3. A range of heat treatment performed after welding is set to a range of approximately the thickness of a member made of Cr-Mo steel and not more than 10 times the thickness of the member. Alternatively, the method for welding chromium-molybdenum steel according to the second item.
もしくは補修溶接前の溶接止端部から少なくとも10mm以
上離れた範囲とすることを特徴とする特許請求の範囲第
１項または第２項に記載のクロム−モリブデン鋼の溶接
方法。4. The range of heat treatment performed after welding is at least 10 mm or more away from the weld toe or the weld toe before repair welding, according to claim 1 or 2. The method for welding chromium-molybdenum steel according to the item 1.
とを特徴とする特許請求の範囲第１項ないし第４項のい
ずれか１項に記載のクロム−モリブデン鋼の溶接方法。5. The welding method for chrome-molybdenum steel according to claim 1, wherein the member made of Cr-Mo steel is a tubular member.
ることを特徴とする特許請求の範囲第１項ないし第５項
のいずれか１項に記載のクロム−モリブデン鋼の溶接方
法。6. The chromium-molybdenum according to any one of claims 1 to 5, wherein the Cr-Mo steel is a 9 wt% Cr-1 wt% Mo steel. How to weld steel.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30383886A JPH0794070B2 (en) | 1986-12-22 | 1986-12-22 | Welding method for chrome-molybdenum steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30383886A JPH0794070B2 (en) | 1986-12-22 | 1986-12-22 | Welding method for chrome-molybdenum steel |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63157769A JPS63157769A (en) | 1988-06-30 |
| JPH0794070B2 true JPH0794070B2 (en) | 1995-10-11 |
Family
ID=17925917
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP30383886A Expired - Fee Related JPH0794070B2 (en) | 1986-12-22 | 1986-12-22 | Welding method for chrome-molybdenum steel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0794070B2 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4903888A (en) | 1988-05-05 | 1990-02-27 | Westinghouse Electric Corp. | Turbine system having more failure resistant rotors and repair welding of low alloy ferrous turbine components by controlled weld build-up |
| JP2809077B2 (en) * | 1993-12-24 | 1998-10-08 | 日本鋼管株式会社 | Steel pipe column |
| JP2020082147A (en) * | 2018-11-27 | 2020-06-04 | 三菱日立パワーシステムズ株式会社 | Pipe material welding method |
| CN109909585B (en) * | 2019-03-12 | 2021-06-25 | 中广核工程有限公司 | Surfacing repair method and system for maintaining welding seam of stainless steel branch pipe |
-
1986
- 1986-12-22 JP JP30383886A patent/JPH0794070B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPS63157769A (en) | 1988-06-30 |
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