JP4128022B2

JP4128022B2 - Groove butt welding method using insert member and insert member used therefor

Info

Publication number: JP4128022B2
Application number: JP2002111005A
Authority: JP
Inventors: 雅一影山; 洋阿久根; 幸夫堀切
Original assignee: Toshiba Plant Systems and Services Corp
Current assignee: Toshiba Plant Systems and Services Corp
Priority date: 2002-04-12
Filing date: 2002-04-12
Publication date: 2008-07-30
Anticipated expiration: 2022-04-12
Also published as: JP2003305568A

Description

【０００１】
【発明の属する技術分野】
本発明は、金属配管材、金属板材等の開先突き合わせ溶接に係り、特にインサート部材を用いた開先突き合わせ溶接方法およびそれに用いるインサート部材に関するものである。
【０００２】
【従来の技術】
金属配管材や金属板材等をＴＩＧ溶接等により突き合わせ溶接する場合における継手断面形式としては、均一で健全な裏波ビード形状を得やすいことから一般にＶ型開先継手形式が用いられている。これは、図１２に示すように母材１０１の継手部１０２における断面形状をＶ型開先形状に加工し、その開先部分（Ｖ溝内）に溶接材（フィラーワイヤー：溶加棒）１０３を溶着、盛り付けして接合強度を得るものである。
【０００３】
継手部１０２は予め所定の間隙ｔを有するように仮固定され、溶接時には溶融した溶接材１０３が間隙ｔから継手部１０２の裏面側にはみ出て凸形状の裏波ビード１０４が形成される。この裏波ビード１０４が溶接長手方向に均一かつ滑らかに形成されることにより接合強度の高い信頼性のある溶接がなされる。よって、裏波ビード１０４の形成には最も注力を要するといっても過言ではない。
【０００４】
従来、裏波ビードの形成をより確実なものにして溶接の信頼性を高めるのに効果のある溶接方法として、図１３に示すように継手部１０２の間にインサート部材１０５を介在させて溶接を行う突き合わせ溶接が行われている。インサート部材１０５は溶接時に溶接材と共に良好に継手部１０２に溶け込み、均一で滑らかな裏波ビードが形成される。なお、金属配管材等を上記のように溶接する場合にはインサート部材１０５がリング状に形成されてインサートリングと呼ばれる。
【０００５】
【発明が解決しようとする課題】
しかしながら、上記のようなインサート部材を用いた開先突き合わせ溶接を行うには、継手部１０２の断面形状を既存のＶ型開先形状からＵ型開先形状となるように追加工し、インサート部材１０５に接触する薄肉かつ肉厚一定のリップ部１０６を形成しなければならず、その加工精度が高く要求される事から加工コストが嵩む上に、溶接前に継手部１０２の間にインサート部材１０５を予め介装して突き合わせ固定する作業（仮付け作業）に多大な手間が掛かるという難点があった。
【０００６】
このため、インサート部材を用いた開先突き合わせ溶接方法は、高品質な溶接方法であるにもかかわらず、主に原子力プラントの重要部等のみにしか採用されていないのが現状である。また、ＴＩＧ溶接より２〜３倍程度高速で高能率化が可能なＭＡＧ溶接の施行を考える場合においても、継手部の加工コストが高いことと仮付け作業が困難な事がネックとなっており、インサート部材を用いた開先突き合わせ溶接が原子力プラント分野を除く火力プラントおよび一般産業分野に普及しにくい大きな要因となっている。
【０００７】
なお、継手部の断面形状をＵ型開先形状ではなくＶ型開先形状としてインサート部材を用いて溶接した場合、初層溶接時に溶接熱がインサート部材と継手部とに均一に伝播されずに双方の溶け込みが不足する等して所望の溶接強度が得られないという問題が生じる。
【０００８】
本発明は、上記問題点を鑑みてなされたものであり、高品質な連続溶接を可能にしつつ、継手部の断面形状としてＶ型開先形状を適用可能にし、継手部の加工コストを低減させるとともに仮付け作業を容易にし、これによりインサート部材を用いた開先突き合わせ溶接を幅広い産業分野に普及させ得るインサート部材を用いた開先突き合わせ溶接方法およびそれに用いるインサート部材を提供することを目的とする。
【０００９】
【課題を解決するための手段】
上記目的を達成するため、本発明に係るインサート部材を用いた開先突き合わせ溶接方法は、請求項１に記載したように、母材のＶ型開先継手部に接触する接触面の厚みＡと、開先継手部間隔方向の厚みＢとの関係が、Ａ＜Ｂ＜３Ａであるインサート部材を形成するインサート部材形成ステップと、このインサート部材を上記母材のＶ型開先継手部に仮付けする仮付けステップと、上記仮付けステップ後に母材のＶ型開先継手部と上記インサート部材とを連続溶接する連続溶接ステップとを有すると共に、上記インサート部材は前記母材のＶ型開先継手部の開先表面側を向く面形状が凹状、開先裏面側を向く面形状が凸状であることを特徴とする。
【００１０】
また、本発明に係るインサート部材を用いた開先突き合わせ溶接方法は、請求項２に記載したように、母材のＶ型開先継手部に接触する接触面の厚みＡと、開先継手部間隔方向の厚みＢとの関係が、Ａ＜Ｂ＜３Ａであるインサート部材を形成するインサート部材形成ステップと、このインサート部材を上記母材のＶ型開先継手部に仮付けする仮付けステップと、上記仮付けステップ後に母材のＶ型開先継手部と上記インサート部材とを連続溶接する連続溶接ステップとを有すると共に、上記インサート部材は前記母材のＶ型開先継手部の開先表面側を向く面形状が凸状、開先裏面側を向く面形状が凹状であることを特徴とする。
【００１１】
また、本発明に係るインサート部材を用いた開先突き合わせ溶接方法は、請求項３に記載したように、母材のＶ型開先継手部に接触する接触面の厚みＡと、開先継手部間隔方向の厚みＢとの関係が、Ａ＜Ｂ＜３Ａであるインサート部材を形成するインサート部材形成ステップと、このインサート部材を上記母材のＶ型開先継手部に仮付けする仮付けステップと、上記仮付けステップ後に母材のＶ型開先継手部と上記インサート部材とを連続溶接する連続溶接ステップとを有すると共に、上記インサート部材は前記母材のＶ型開先継手部の開先表面側を向く面形状と開先裏面側を向く面形状とが共に凹状であることを特徴とする。
【００１２】
これらの溶接方法によれば、溶接熱源から入力された熱エネルギーが効率良くＶ型開先継手部とインサート部材とに伝達されて双方が良好に融合でき、これにより初層溶接時に均等かつ滑らかな凸形状の裏波ビードが得られる。したがって、高品質かつ高効率な連続溶接が可能になるとともに、継手部の断面形状としてＶ型開先形状が適用可能になり、継手部の加工コスト低減と仮付け作業の容易化に繋がる。
【００１３】
また、上記の各態様でインサート部材を形成すれば、凸状、凹状の曲面によりインサート部材の表面積が増加し、これにより溶接熱源から入力された熱エネルギーがより効率良くインサート部材に伝達されるため、その分インサート部材の開先継手部間隔方向の厚みＢを小さく設定することが可能になり、Ｖ型開先継手部の開先断面積、即ち溶融プールの断面積を小さくし、より高効率な溶接が可能になる。
【００１４】
さらに、本発明に係るインサート部材を用いた開先突き合わせ溶接方法は、請求項４に記載したように、前記母材の材質を、炭素鋼、低合金鋼、ステンレス鋼の少なくとも１種類以上の材料を用いることを特徴とする。これにより、高い溶接強度が得られる。
【００１５】
また、本発明に係るインサート部材を用いた開先突き合わせ溶接方法は、請求項５に記載したように、前記インサート部材を前記母材のＶ型開先継手部に仮付けする仮付けステップにおいて、インサート部材の一側を母材の一方のＶ型開先継手部に仮付けした後、インサート部材の他側を母材の他方のＶ型開先継手部に仮付けすることを特徴とする。こうすれば、仮付け作業を容易にすることができる。
【００１６】
そして、本発明に係るインサート部材を用いた開先突き合わせ溶接方法は、請求項６に記載したように前記母材と同等な溶接材料で製作されたフィラーワイヤー（溶加棒）を別途適量供給しながらＴＩＧ溶接を行う、または請求項７に記載したように前記母材と同等な溶接材料で製作されたフィラーワイヤー（溶加棒）を消耗電極として使用し、このフィラーワイヤーを別途適量供給しながらＭＡＧ溶接を行うことを特徴とする。これらにより、高い溶接強度の確保と連続した裏波ビードの形成が可能になるとともに、溶着効率の向上を図ることができる。
【００１７】
また、本発明に係るインサート部材は、請求項８に記載したように、母材のＶ型開先継手部に接触する接触面の厚みＡと、開先継手部間隔方向の厚みＢとの関係が、Ａ＜Ｂ＜３Ａであると共に、前記母材のＶ型開先継手部の開先表面側を向く面形状が凹状、開先裏面側を向く面形状が凸状であることを特徴とする。
【００１８】
また、本発明に係るインサート部材は、請求項９に記載したように、母材のＶ型開先継手部に接触する接触面の厚みＡと、開先継手部間隔方向の厚みＢとの関係が、Ａ＜Ｂ＜３Ａであると共に、前記母材のＶ型開先継手部の開先表面側を向く面形状が凸状、開先裏面側を向く面形状が凹状であることを特徴とする。
さらに、本発明に係るインサート部材は、請求項１０に記載したように、母材のＶ型開先継手部に接触する接触面の厚みＡと、開先継手部間隔方向の厚みＢとの関係が、Ａ＜Ｂ＜３Ａであると共に、前記母材のＶ型開先継手部の開先表面側を向く面形状と開先裏面側を向く面形状とが共に凹状であることを特徴とする。
これらのインサート部材によれば、溶接熱源から入力された熱エネルギーが効率良くＶ型開先継手部とインサート部材とに伝達されて双方が良好に融合でき、これにより初層溶接時に均等かつ滑らかな凸形状の裏波ビードが得られる。したがって、高品質かつ高効率な連続溶接が可能になるとともに、継手部の断面形状としてＶ型開先形状が適用可能になり、継手部の加工コスト低減と仮付け作業の容易化に繋がる。
また、上記の各態様でインサート部材を形成すれば、凸状、凹状の曲面によりインサート部材の表面積が増加し、これにより溶接熱源から入力された熱エネルギーがより効率良くインサート部材に伝達されるため、その分インサート部材の開先継手部間隔方向の厚みＢを小さく設定することが可能になり、Ｖ型開先継手部の開先断面積、即ち溶融プールの断面積を小さくし、より高効率な溶接が可能になる。
さらにまた、本発明に係るインサート部材は、請求項１１に記載したように、前記接触面の厚みＡを前記母材の開先継手部間の食い違い公差寸法よりも少なくとも０．５ｍｍ大きくしたことを特徴とする。これにより、開先継手部の食い違いが最大量であったとしても、少なくとも０．５ｍｍ以上の接合面が得られて溶接が可能になる。
また、本発明に係るインサート部材は、請求項１２に記載したように、前記接触面の厚みＡが１．０ｍｍ〜３．０ｍｍの範囲内であることを特徴とする。このようにインサート部材の厚みＡを設定することにより、インサート部材とＶ型開先継手部との間における溶け残りや、Ｖ型開先継手部のＶ溝内における溶融プールの溶け落ち等が起きにくくなり、より健全な裏波ビードを形成して高品質な連続溶接が可能になる。請求項１３に記載したように接触面の厚みＡを２．０ｍｍに設定すればより好ましい。
【００１９】
【発明の実施の形態】
以下、本発明の実施形態を図面に基づいて説明する。図１は、本発明に係る溶接方法を金属配管材に適用した例を示す側面図である。溶接の母材となる金属配管材１，１の継手部（接合部）２はＶ型開先形状に加工され、その間にリング状に形成されたインサート部材（インサートリング）３が介装される。
【００２０】
図２（ａ）は、図１に示す金属配管材１，１の継手部２とインサート部材３とを密着させた部分を示す拡大断面図であり、図２（ｂ）はインサート部材３単体の断面図である。継手部２は例えばＪＩＳ規格に基づくＶ型開先形状に加工され、その開先面４，４の傾斜角度は例えば３０°に設定され、先端となるルート面５，５にインサート部材３の接触面６，６が突き当てられて溶接される。
【００２１】
インサート部材は、接触面６，６の厚みＡと、開先継手部間隔方向の厚みＢとの関係が、Ａ＜Ｂ＜３Ａとなるように寸法設定される。一例として、Ａ＝２ｍｍとした場合、Ｂは２ｍｍを超え、かつ６ｍｍ未満に設定される。
【００２２】
また、上記Ａ寸法は、母材である金属配管材１，１の継手部２の食い違い公差寸法よりも少なくとも０．５ｍｍ大きく設定される。上記寸法とすることにより、継手部２の食い違いが最大量であったとしても、少なくとも０．５ｍｍ以上の接合面が得られて溶接が可能になり、信頼性が高まる。
【００２３】
上記Ａ寸法は、１．０ｍｍ〜３．０ｍｍの範囲内に設定するのが良く、その中間値の２．０ｍｍに設定するのが最も好ましい。
【００２４】
さらに、インサート部材３の、継手部２の開先表面側（金属配管材１，１の外面側）を向く外面８の面形状が凹状、開先裏面側（金属配管材１，１の内面側）を向く内面９の面形状が凸状に形成されている。これらの凹凸形状は例えば滑らかな湾曲面状に形成される。
【００２５】
また、図３（ａ），（ｂ）に示すインサート部材３ａのように外面８の面形状を凸状、内面９の面形状を凹状に形成したり、図４（ａ），（ｂ）に示すインサート部材３ｂのように外面８の面形状と内面９の面形状を共に凹状に形成してもよい。いずれのインサート部材３，３ａ，３ｂの場合も、Ａ寸法とＢ寸法の関係が、Ａ＜Ｂ＜３Ａとなるように設定し、Ａ寸法を１．０ｍｍ〜３．０ｍｍの範囲内、好ましくは２．０ｍｍに設定する。
【００２６】
本発明に係る開先突き合わせ溶接方法は、上記仕様のインサート部材３（３ａ，３ｂ）を形成するインサート部材形成ステップと、このインサート部材３を金属配管材１，１の継手部２に仮付けする仮付けステップと、上記仮付けステップ後に継手部２とインサート部材３とを連続溶接する連続溶接ステップとを有してなる。
【００２７】
前記仮付けステップの手順を図５（ａ），（ｂ），（ｃ）に示す。まず、（ａ）に示すようにインサート部材３の片側の接触面６を継手部２の一方のルート面５に当接させ、次に（ｂ）に示すようにインサート部材３と一方のルート面５との間を一定ピッチの点溶接１１等により仮付けし、最後に（ｃ）に示すようにインサート部材３の他側の接触面６を継手部２の他方のルート面５に当接させて同じく点溶接１１等により仮付けする。仮付けされた部分の断面は図６に示すようなものとなる。
【００２８】
このような手順でインサート部材３と継手部２との間を仮付けすることにより、継手部２の間を治具等で固定する必要がなくなり、仮付け作業を容易にすることができる。
【００２９】
次に、前記連続溶接ステップについて説明する。これは本溶接とも呼ばれるステップであり、下記のＴＩＧ溶接またはＭＡＧ溶接によって良好に成し遂げることができる。この連続溶接ステップは自動あるいは手動溶接により行われる。
【００３０】
ＴＩＧ溶接では、図７に示すように溶接トーチ１３先端のタングステン等で形成された非消耗電極１４からのアーク放電により、継手部２とインサート部材３とが加熱、溶融される。同時に、母材（金属配管材１，１）と同等な溶接材料で製作されたフィラーワイヤー（溶加棒）１５が別途適量供給され、このフィラーワイヤー１５が継手部２の開先面４，４とインサート部材３とがなすＶ溝内において溶融し、溶融プール１６を形成する。溶融プール１６は開先面４，４とインサート部材３とに融合し、同時にルート面５，５とインサート部材３との間も融合する。そして、図８に示すように溶接ビード１７が形成されて継手部２が溶接される。なお、溶接トーチ１３からは溶接部に向ってシールドガス（不活性ガス）１８が噴き付けられる。
【００３１】
一方、ＭＡＧ溶接では、図９に示すように溶接トーチ２１に設けられた電極２２が母材（金属配管材１，１）と同等な溶接材料で製作されており、この電極２２がアーク放電を行いつつ、フィラーワイヤー（溶加棒）として適量供給される消耗電極として機能する。電極２２は継手部２の開先面４，４とインサート部材３とがなすＶ溝内において溶融プール２３を形成し、ＴＩＧ溶接の場合と同様に溶接ビード１７（図８参照）が形成される。ＭＡＧ溶接の場合も溶接トーチ２１から溶接部に向ってシールドガス（活性ガス）２４が噴き付けられる。
【００３２】
ＴＩＧ溶接、ＭＡＧ溶接、いずれの溶接方法においても、溶接ビード１７（図８）は継手部２の表裏両側に若干はみ出す凸形断面をなし、特に継手部２の裏側にはみ出した部分１７ａが裏波ビードと呼ばれ、この裏波ビード１７ａが溶接長手方向に均一かつ滑らかに形成されることにより溶接の接合強度が高められる。インサート部材３の介装は裏波ビード１７ａの形成をより確実なものにする。このように、インサート部材３を用いてＴＩＧ溶接またはＭＡＧ溶接によって連続溶接（本溶接）を行うことにより、高い溶接強度の確保と連続した裏波ビード１７ａの形成を可能にするとともに、溶着効率の向上を図ることができる。
【００３３】
溶接ビード１７（溶融プール１６，２３）の形成は、母材（金属配管材１，１）の厚みに応じて複数回に分けて実行され、例えば図８の溶接ビード１７は１層目１７ｂと２層目１７ｃからなる２層構造となっている。裏波ビード１７ａは１層目１７ｂの形成時に同時形成される。
【００３４】
母材（金属配管材１，１）の材質は、炭素鋼、低合金鋼、ステンレス鋼の少なくとも１種類以上の材料を用いれば、高い溶接強度を得ることができる。
【００３５】
本発明では、インサート部材３の接触面６の厚みＡと、開先継手部間隔方向の厚みＢとの関係をＡ＜Ｂ＜３Ａとなるように定めたことにより、溶接トーチ１３，２１等の溶接熱源から入力された熱エネルギーを効率良く継手部２とインサート部材３とに伝達させて双方を良好に融合させ、これにより初層（１層目１７ｂ）の溶接時に均等かつ滑らかな凸形状の裏波ビード１７ａを得ることができる。
【００３６】
したがって、高品質かつ高効率な連続溶接が可能になるとともに、継手部２の断面形状として既存のＶ型開先形状が適用可能になるため、従来の加工困難なＵ型開先形状等にする必要がなく、継手部２の加工コスト低減と仮付け作業の容易化を達成することができる。
【００３７】
ところで、図１０に示すように、Ｖ型開先形状を適用した状態で、インサート部材３のＡ，Ｂ寸法の関係をＡ＞Ｂとした場合には、図２〜図４に示す本発明のＡ＜Ｂの状態と比較して開先継手のＶ溝断面積が著しく減少することにより、初層溶接時に溶融プール２６が開先面４，４と接触する面積が増加する。この事が溶接熱源からの熱エネルギーの伝導範囲２７を拡張させ、熱エネルギーを母材１，１側に過大に分散させてしまう。その結果、熱エネルギー効率が非常に悪くなり、ルート面５とインサート部材３との間に融合不良等に起因する溶接欠陥が生じやすくなることが実験により確認されている。
【００３８】
逆に、図１１に示すように、インサート部材３のＢ寸法がＡ寸法に対し過大（実験では３倍を大きく超えた場合）になると、溶接時における溶融プール２６の深度が不足して熱エネルギーの伝導範囲２７が著しく縮小され、熱エネルギーがインサート部材３にのみ集中し、表面張力によりバランスしている溶融プール２６を維持できずに溶け落ち現象が発生する。しかも、開先継手のＶ溝断面積が大きくなることにより、フィラーワイヤー（溶加棒）の必要量が増加するとともに溶接作業時間が長くなるといった弊害があり、溶接作業効率とコスト面で極めて不利である。
【００３９】
したがって、継手部２の断面形状としてＶ型開先形状を適用可能にしつつ、熱エネルギーを効率良くルート面５，５とインサート部材３に伝達してインサート部材３を過不足なく良好に融合させるためには、本発明のようにインサート部材３のＡ寸法とＢ寸法の関係が、Ａ＜Ｂ＜３Ａであることが望ましい。
【００４０】
インサート部材３のＢ寸法が小さくなる程、Ｖ字開先継手のＶ溝断面積、即ち溶融プールの断面積が小さくなって溶接作業効率とコスト面においては有利になる。しかしその反面、前述の如く熱エネルギー効率が悪くなることにより、ルート面５，５とインサート部材３との間に融合不良等に起因する溶接欠陥が生じやすくもなる。
【００４１】
そこで、本発明のようにインサート部材３の外面８および内面９の面形状を凹状、または凸状とすれば、インサート部材３の表面積が増加し、これにより熱エネルギーが効率良くインサート部材３に伝達されるため、その分インサート部材３のＢ寸法を小さく設定することが可能になり、より高効率な溶接が可能になる。
【００４２】
一方、実験によれば、インサート部材３のＡ寸法を２．０ｍｍに設定すると、初層溶接時に均等で滑らかな凸形状の裏波ビードが容易に得られることが判明している。
【００４３】
しかし、Ａ寸法を０．５ｍｍと薄く設定した場合には、初層溶接時に溶融プールの溶け落ち現象が頻繁に発生し、この条件下で適正な裏波ビード形状を得るためには必然的に溶接電流を低く設定せざるを得ず、これにより接効率が低下して溶接施工条件の許容範囲が狭くなるため非実用的である。
【００４４】
逆に、Ａ寸法を３．５ｍｍと厚く設定した場合には、インサート部材３の厚みが増加したことで加熱の必要なエリアが増大し、インサート部材３とルート面５，５とが充分に融合出来なくなって溶接欠陥が発生しやすい。
【００４５】
これらの実験結果から、インサート部材のＡ寸法を１．０ｍｍ〜３．０ｍｍに設定すれば、安定した良好な裏波ビードを得ることができる。その中でも中央値の２．０ｍｍが最適な寸法であると判断できる。
【００４６】
また、図１３に示す従来のＵ型開先形状の継手部１０２にインサート部材１０５を介装して溶接した場合に形成された溶接ビードと、図２に示す本発明に係る溶接方法およびインサート部材３により形成された溶接ビードとを冶金学的に比較した場合、従来の溶接ビードは母材と溶接金属（フィラーワイヤーおよびインサート部材）とが約５０％の割合で混合した溶着金属となるのに対し、本発明における溶接ビードは約９０％が溶接金属となり、母材との希釈率が小さくて溶接部の機械的性質や耐食性等も従来に比べて優れていることが判明した。したがって、この点でも本発明による溶接方法およびインサート部材は従来のものよりも優れていると言える。
【００４７】
なお、上記実施形態では溶接母材が金属配管材である場合の例についてのみ説明したが、本発明に係る溶接方法およびインサート部材は金属配管材に限らず、金属板や、他の多くの形状の構造材等の突き合わせ溶接にも幅広く適用することができる。
【００４８】
【発明の効果】
以上説明したように、本発明に係るインサート部材を用いた開先突き合わせ溶接方法およびそれに用いるインサート部材よれば、高品質で信頼性の高い連続溶接を可能にしつつ、継手部の断面形状として既存のＶ型開先形状を追加工なしで適用可能にし、継手部の加工コストを低減させるとともに仮付け作業を容易にし、これによりインサート部材を用いた高品質な開先突き合わせ溶接を幅広い産業分野にローコストで普及させることができる。
【図面の簡単な説明】
【図１】本発明に係る溶接方法を金属配管材に適用した例を示す側面図。
【図２】本発明の第１実施形態を示すもので、（ａ）は継手部とインサート部材とを密着させた部分を示す拡大断面図、（ｂ）はインサート部材単体の断面図。
【図３】本発明の第２実施形態を示すもので、（ａ）は継手部とインサート部材とを密着させた部分拡大断面図、（ｂ）はインサート部材単体の断面図。
【図４】本発明の第３実施形態を示すもので、（ａ）は継手部とインサート部材とを密着させた部分拡大断面図、（ｂ）はインサート部材単体の断面図。
【図５】仮付けステップの手順を示すもので、（ａ）はインサート部材を一方の継手部に当接させた状態を示す図、（ｂ）はインサート部材と一方の継手部とを仮付けした状態を示す図、（ｃ）はインサートを他方ｃの継手部に当接させて仮付けした状態を示す図。
【図６】図５（ｃ）のＶＩ−ＶＩ線に沿う断面図。
【図７】ＴＩＧ溶接の概略説明図。
【図８】溶接ビードの断面図。
【図９】ＭＡＧ溶接の概略説明図。
【図１０】Ｖ型開先形状を適用した状態でインサート部材のＡ，Ｂ寸法の関係をＡ＞Ｂとした場合を示す断面図。
【図１１】インサート部材のＢ寸法がＡ寸法に対し過大な場合を示す断面図。
【図１２】従来の技術を示すインサート部材を用いないＶ型開先溶接部の断面図。
【図１３】従来の技術を示すインサート部材を用いたＵ型開先溶接部の断面図。
【符号の説明】
１母材となる金属配管材
２継手部
３インサート部材
４開先面
５ルート面
６接触面
８Ｖ型開先継手部の開先表面側を向く面
９Ｖ型開先継手部の開先裏面側を向く面
１５ＴＩＧ溶接時におけるフィラーワイヤー（溶加棒）
２２ＭＡＧ溶接時におけるフィラーワイヤー（溶加棒）となる電極[0001]
BACKGROUND OF THE INVENTION
The present invention relates to groove butt welding of metal piping materials, metal plate materials, and the like, and particularly to a groove butt welding method using an insert member and an insert member used therefor.
[0002]
[Prior art]
In general, a V-shaped groove joint format is used as a joint cross-section format when a metal pipe material, a metal plate material, or the like is butt-welded by TIG welding or the like, because a uniform and sound back bead shape is easily obtained. As shown in FIG. 12, the cross-sectional shape of the joint portion 102 of the base material 101 is processed into a V-shaped groove shape, and a welding material (filler wire: filler rod) 103 is formed in the groove portion (in the V groove). Are welded and arranged to obtain bonding strength.
[0003]
The joint portion 102 is temporarily fixed so as to have a predetermined gap t in advance, and the welded material 103 melted at the time of welding protrudes from the gap t to the back side of the joint portion 102 to form a convex back bead 104. By forming the back bead 104 uniformly and smoothly in the longitudinal direction of welding, reliable welding with high joint strength is performed. Therefore, it is no exaggeration to say that the formation of the back bead 104 requires the most effort.
[0004]
Conventionally, as an effective welding method for improving the reliability of welding by ensuring the formation of a back bead, welding is performed by inserting an insert member 105 between joint portions 102 as shown in FIG. Butt welding is done. The insert member 105 is well melted into the joint portion 102 together with the welding material during welding, and a uniform and smooth back bead is formed. In addition, when welding a metal piping material etc. as mentioned above, the insert member 105 is formed in a ring shape and is called an insert ring.
[0005]
[Problems to be solved by the invention]
However, in order to perform groove butt welding using the insert member as described above, the cross-sectional shape of the joint portion 102 is additionally processed so as to be a U-shaped groove shape from the existing V-shaped groove shape, and the insert member A thin lip portion 106 having a constant thickness has to be formed in contact with 105, and its processing accuracy is required to be high, so that the processing cost is increased and the insert member 105 is interposed between the joint portions 102 before welding. There is a problem in that it takes a lot of time and effort to tackle and fix them in advance (tacking work).
[0006]
For this reason, the groove butt welding method using an insert member is currently employed only for important parts of a nuclear power plant, although it is a high-quality welding method. In addition, when considering the implementation of MAG welding, which can achieve high efficiency at a speed about 2 to 3 times faster than TIG welding, the high processing cost of the joints and the difficulty of tacking work are the bottleneck. Groove butt welding using an insert member is a major factor that is difficult to spread in thermal power plants and general industrial fields except for the nuclear power plant field.
[0007]
In addition, when the cross-sectional shape of the joint portion is welded using an insert member instead of a U-shaped groove shape instead of a U-shaped groove shape, the welding heat is not uniformly transmitted to the insert member and the joint portion during the first layer welding. There arises a problem that a desired welding strength cannot be obtained due to insufficient penetration of both.
[0008]
The present invention has been made in view of the above-described problems, and enables a V-shaped groove shape to be applied as a cross-sectional shape of a joint portion while enabling high-quality continuous welding, thereby reducing the processing cost of the joint portion. It is another object of the present invention to provide a groove butt welding method using an insert member and an insert member used for the same, which facilitates a tacking operation and thereby can spread groove butt welding using the insert member in a wide range of industrial fields. .
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the groove butt welding method using the insert member according to the present invention includes, as described in claim 1, a thickness A of a contact surface that contacts a V-shaped groove joint portion of a base material, and An insert member forming step for forming an insert member in which the relationship with the thickness B in the interval direction of the groove joint portion is A <B <3A, and the insert member is temporarily attached to the V-shaped groove joint portion of the base material. And a continuous welding step for continuously welding the V-shaped groove joint portion of the base material and the insert member after the temporary fixing step, and the insert member is a V-shaped groove joint of the base material. The surface shape facing the groove surface side of the part is concave, and the surface shape facing the groove back surface side is convex .
[0010]
Further, according to the groove butt welding method using the insert member according to the present invention, as described in claim 2, the thickness A of the contact surface that contacts the V-shaped groove joint portion of the base material, and the groove joint portion An insert member forming step for forming an insert member in which the relationship with the thickness B in the interval direction is A <B <3A; and a temporary attaching step for temporarily attaching the insert member to the V-shaped groove joint portion of the base material. And a continuous welding step for continuously welding the V-shaped groove joint portion of the base material and the insert member after the tacking step, and the insert member is a groove surface of the V-shaped groove joint portion of the base material. The surface shape facing the side is convex, and the surface shape facing the groove back side is concave .
[0011]
Further, according to the groove butt welding method using the insert member according to the present invention, as described in claim 3, the thickness A of the contact surface that contacts the V-shaped groove joint portion of the base material, and the groove joint portion An insert member forming step for forming an insert member in which the relationship with the thickness B in the interval direction is A <B <3A; and a temporary attaching step for temporarily attaching the insert member to the V-shaped groove joint portion of the base material. And a continuous welding step for continuously welding the V-shaped groove joint portion of the base material and the insert member after the tacking step, and the insert member is a groove surface of the V-shaped groove joint portion of the base material. The surface shape facing the side and the surface shape facing the groove back side are both concave .
[0012]
According to these welding methods, the heat energy input from the welding heat source is efficiently transmitted to the V-shaped groove joint portion and the insert member, so that both can be fused well, and thereby uniform and smooth during the first layer welding. A convex backside bead is obtained. Accordingly, high-quality and high-efficiency continuous welding is possible, and a V-shaped groove shape can be applied as the cross-sectional shape of the joint portion, which leads to a reduction in processing cost of the joint portion and facilitation of a tacking operation.
[0013]
In addition, if the insert member is formed in each of the above aspects, the surface area of the insert member increases due to the convex and concave curved surfaces, so that the heat energy input from the welding heat source is more efficiently transmitted to the insert member. Accordingly, the thickness B of the insert member in the gap joint portion interval direction can be set small, and the groove cross-sectional area of the V-shaped groove joint portion, that is, the cross-sectional area of the molten pool is reduced, so that the efficiency is increased. Welding is possible.
[0014]
Furthermore, in the groove butt welding method using the insert member according to the present invention, as described in claim 4, the base material is made of at least one material selected from carbon steel, low alloy steel, and stainless steel. It is characterized by using. Thereby, high welding strength is obtained.
[0015]
Moreover, in the groove butt welding method using the insert member according to the present invention, as described in claim 5, in the temporary attachment step of temporarily attaching the insert member to the V-shaped groove joint portion of the base material, After temporarily attaching one side of the insert member to one V-shaped groove joint portion of the base material, the other side of the insert member is temporarily attached to the other V-type groove joint portion of the base material. In this way, the tacking work can be facilitated.
[0016]
The groove butt welding method using the insert member according to the present invention separately supplies an appropriate amount of filler wire (melting rod) made of a welding material equivalent to the base material as described in claim 6. While performing TIG welding or using a filler wire (fuse rod) made of a welding material equivalent to the base material as described in claim 7 as a consumable electrode and supplying an appropriate amount of this filler wire separately MAG welding is performed. As a result, it is possible to ensure high welding strength and to form a continuous back bead, and to improve the welding efficiency.
[0017]
The insert member according to the present invention has a relationship between the thickness A of the contact surface contacting the V-shaped groove joint portion of the base material and the thickness B in the gap joint portion interval direction, as described in claim 8. A <B <3A, and the shape of the V-shaped groove joint portion of the base material facing the groove surface side is concave, and the surface shape facing the groove back surface side is convex. To do.
[0018]
Moreover, the insert member which concerns on this invention is the relationship between the thickness A of the contact surface which contacts the V-shaped groove joint part of a preform | base_material, and the thickness B of a groove joint part space | interval direction, as described in Claim 9. However, A <B <3A, and the surface shape facing the groove surface side of the V-shaped groove joint portion of the base material is convex, and the surface shape facing the groove back surface side is concave. To do.
Furthermore, as described in claim 10, the insert member according to the present invention has a relationship between the thickness A of the contact surface contacting the V-shaped groove joint portion of the base material and the thickness B in the gap joint portion interval direction. However, A <B <3A, and the surface shape facing the groove surface side and the surface shape facing the groove back surface side of the V-shaped groove joint portion of the base material are both concave. .
According to these insert members, the heat energy input from the welding heat source is efficiently transmitted to the V-shaped groove joint portion and the insert member, so that both can be fused well, and thereby uniform and smooth during the first layer welding. A convex backside bead is obtained. Accordingly, high-quality and high-efficiency continuous welding is possible, and a V-shaped groove shape can be applied as the cross-sectional shape of the joint portion, which leads to a reduction in processing cost of the joint portion and facilitation of a tacking operation.
In addition, if the insert member is formed in each of the above aspects, the surface area of the insert member increases due to the convex and concave curved surfaces, so that the heat energy input from the welding heat source is more efficiently transmitted to the insert member. Accordingly, the thickness B of the insert member in the gap joint portion interval direction can be set small, and the groove cross-sectional area of the V-shaped groove joint portion, that is, the cross-sectional area of the molten pool is reduced, so that the efficiency is increased. Welding is possible.
Furthermore, in the insert member according to the present invention, as described in claim 11, the thickness A of the contact surface is set to be at least 0.5 mm larger than a gap tolerance dimension between groove joint portions of the base material. Features. Thereby, even if the gap of the groove joint portion is the maximum amount, a joining surface of at least 0.5 mm or more is obtained and welding is possible.
Moreover, the insert member according to the present invention is characterized in that, as described in claim 12, the thickness A of the contact surface is in the range of 1.0 mm to 3.0 mm. By setting the thickness A of the insert member in this way, unmelted residue between the insert member and the V-shaped groove joint portion, melting of the molten pool in the V-groove of the V-shaped groove joint portion, or the like occurs. It becomes difficult to form a sounder backside bead and enables high-quality continuous welding. More preferably, the thickness A of the contact surface is set to 2.0 mm.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a side view showing an example in which the welding method according to the present invention is applied to a metal piping material. The joint part (joint part) 2 of the metal piping materials 1 and 1 as a base material for welding is processed into a V-shaped groove shape, and an insert member (insert ring) 3 formed in a ring shape is interposed therebetween. .
[0020]
2A is an enlarged cross-sectional view showing a portion where the joint portion 2 and the insert member 3 of the metal piping materials 1 and 1 shown in FIG. 1 are brought into close contact with each other, and FIG. It is sectional drawing. The joint portion 2 is processed into a V-shaped groove shape based on, for example, JIS standards, and the inclination angle of the groove surfaces 4 and 4 is set to 30 °, for example. The faces 6 and 6 are abutted and welded.
[0021]
The insert member is dimensioned so that the relationship between the thickness A of the contact surfaces 6 and 6 and the thickness B in the groove joint interval direction is A <B <3A. As an example, when A = 2 mm, B is set to exceed 2 mm and less than 6 mm.
[0022]
Further, the dimension A is set to be at least 0.5 mm larger than the gap tolerance dimension of the joint portion 2 of the metal piping materials 1 and 1 as the base material. By setting it as the said dimension, even if the discrepancy of the joint part 2 is the maximum amount, the joining surface of at least 0.5 mm or more is obtained, welding becomes possible, and reliability increases.
[0023]
The dimension A is preferably set within a range of 1.0 mm to 3.0 mm, and most preferably set to an intermediate value of 2.0 mm.
[0024]
Furthermore, the shape of the outer surface 8 of the insert member 3 facing the groove surface side (the outer surface side of the metal piping materials 1 and 1) of the joint portion 2 is concave, and the groove rear surface side (the inner surface side of the metal piping materials 1 and 1). ) Is formed in a convex shape. These concavo-convex shapes are formed in a smooth curved surface, for example.
[0025]
Also, like the insert member 3a shown in FIGS. 3 (a) and 3 (b), the outer surface 8 has a convex surface shape, and the inner surface 9 has a concave surface shape. You may form both the surface shape of the outer surface 8 and the surface shape of the inner surface 9 in the concave shape like the insert member 3b shown. For any of the insert members 3, 3a, 3b, the relationship between the A dimension and the B dimension is set so that A <B <3A, and the A dimension is within the range of 1.0 mm to 3.0 mm, preferably Set to 2.0 mm.
[0026]
In the groove butt welding method according to the present invention, an insert member forming step for forming the insert member 3 (3a, 3b) having the above specifications and the insert member 3 are temporarily attached to the joint portion 2 of the metal piping materials 1, 1. A temporary attachment step and a continuous welding step of continuously welding the joint portion 2 and the insert member 3 after the temporary attachment step are provided.
[0027]
The procedure of the tacking step is shown in FIGS. 5 (a), (b) and (c). First, as shown in (a), the contact surface 6 on one side of the insert member 3 is brought into contact with one route surface 5 of the joint portion 2, and then the insert member 3 and one route surface as shown in (b). 5 is temporarily attached by spot welding 11 or the like having a constant pitch, and finally the contact surface 6 on the other side of the insert member 3 is brought into contact with the other root surface 5 of the joint portion 2 as shown in (c). Similarly, it is temporarily attached by spot welding 11 or the like. The section of the temporarily attached portion is as shown in FIG.
[0028]
By temporarily attaching between the insert member 3 and the joint part 2 in such a procedure, it is not necessary to fix the joint part 2 with a jig or the like, and the provisional work can be facilitated.
[0029]
Next, the continuous welding step will be described. This is a step called main welding, and can be satisfactorily achieved by the following TIG welding or MAG welding. This continuous welding step is performed by automatic or manual welding.
[0030]
In TIG welding, the joint portion 2 and the insert member 3 are heated and melted by arc discharge from a non-consumable electrode 14 formed of tungsten or the like at the tip of the welding torch 13 as shown in FIG. At the same time, an appropriate amount of filler wire (melting rod) 15 made of a welding material equivalent to the base material (metal piping materials 1, 1) is supplied separately, and this filler wire 15 is connected to the groove surfaces 4, 4 of the joint portion 2. And the insert member 3 are melted in a V groove to form a melt pool 16. The molten pool 16 is fused to the groove surfaces 4, 4 and the insert member 3, and at the same time, the root surfaces 5, 5 and the insert member 3 are also fused. And as shown in FIG. 8, the weld bead 17 is formed and the joint part 2 is welded. A shield gas (inert gas) 18 is sprayed from the welding torch 13 toward the welded portion.
[0031]
On the other hand, in MAG welding, as shown in FIG. 9, the electrode 22 provided on the welding torch 21 is made of a welding material equivalent to the base material (metal piping materials 1 and 1), and this electrode 22 causes arc discharge. While performing, it functions as a consumable electrode supplied as an appropriate amount as a filler wire (melting rod). The electrode 22 forms a molten pool 23 in a V groove formed by the groove surfaces 4 and 4 of the joint portion 2 and the insert member 3, and a weld bead 17 (see FIG. 8) is formed in the same manner as in the case of TIG welding. . Also in the case of MAG welding, shield gas (active gas) 24 is sprayed from the welding torch 21 toward the welded portion.
[0032]
In any of the TIG welding and MAG welding methods, the weld bead 17 (FIG. 8) has a convex cross section that slightly protrudes on both the front and back sides of the joint portion 2, and in particular, a portion 17 a that protrudes from the back side of the joint portion 2 is a reverse wave. This weld bead 17a is formed uniformly and smoothly in the longitudinal direction of the weld so that the welding joint strength is increased. The insertion of the insert member 3 ensures the formation of the back bead 17a. Thus, by performing continuous welding (main welding) by TIG welding or MAG welding using the insert member 3, it is possible to ensure high welding strength and to form a continuous back bead 17a and to improve the welding efficiency. Improvements can be made.
[0033]
The formation of the weld bead 17 (molten pool 16, 23) is executed in multiple steps according to the thickness of the base material (metal piping material 1, 1). For example, the weld bead 17 in FIG. It has a two-layer structure composed of the second layer 17c. The back bead 17a is formed simultaneously with the formation of the first layer 17b.
[0034]
If the base material (metal piping materials 1, 1) is at least one material selected from the group consisting of carbon steel, low alloy steel, and stainless steel, high welding strength can be obtained.
[0035]
In the present invention, the relationship between the thickness A of the contact surface 6 of the insert member 3 and the thickness B in the gap joint portion interval direction is determined so that A <B <3A. The heat energy input from the welding heat source is efficiently transmitted to the joint portion 2 and the insert member 3 so that both are well fused, and thereby an even and smooth convex shape is formed when the first layer (first layer 17b) is welded. The back bead 17a can be obtained.
[0036]
Accordingly, high-quality and high-efficiency continuous welding becomes possible, and the existing V-shaped groove shape can be applied as the cross-sectional shape of the joint portion 2, so that a conventional U-shaped groove shape that is difficult to process is used. There is no need, and it is possible to reduce the processing cost of the joint portion 2 and facilitate the tacking operation.
[0037]
By the way, as shown in FIG. 10, when the relationship between the dimensions A and B of the insert member 3 is A> B in the state where the V-shaped groove shape is applied, the present invention shown in FIGS. Compared with the state of A <B, the groove groove cross-sectional area of the groove joint is remarkably reduced, so that the area where the molten pool 26 contacts the groove surfaces 4 and 4 during the first layer welding is increased. This expands the conduction range 27 of the heat energy from the welding heat source, and the heat energy is excessively dispersed on the base materials 1 and 1 side. As a result, it has been confirmed by experiments that the thermal energy efficiency is extremely deteriorated and that a welding defect due to poor fusion or the like is likely to occur between the root surface 5 and the insert member 3.
[0038]
On the contrary, as shown in FIG. 11, when the B dimension of the insert member 3 is excessively large with respect to the A dimension (when greatly exceeding three times in the experiment), the depth of the molten pool 26 at the time of welding is insufficient and the heat energy is increased. The conduction range 27 is significantly reduced, the thermal energy is concentrated only on the insert member 3, and the molten pool 26 that is balanced by the surface tension cannot be maintained, so that the melting phenomenon occurs. In addition, since the V-groove cross-sectional area of the groove joint increases, there is an adverse effect that the required amount of filler wire (melting rod) increases and the welding operation time becomes long, which is extremely disadvantageous in terms of welding operation efficiency and cost. It is.
[0039]
Therefore, in order to fuse the insert member 3 satisfactorily without excess or deficiency while efficiently applying heat energy to the root surfaces 5 and 5 and the insert member 3 while making it possible to apply a V-shaped groove shape as the cross-sectional shape of the joint portion 2. For this reason, it is desirable that the relationship between the A dimension and the B dimension of the insert member 3 is A <B <3A as in the present invention.
[0040]
The smaller the B dimension of the insert member 3, the smaller the V groove cross-sectional area of the V-shaped groove joint, that is, the cross-sectional area of the molten pool, which is advantageous in terms of welding work efficiency and cost. On the other hand, however, the thermal energy efficiency is deteriorated as described above, so that a welding defect due to poor fusion or the like tends to occur between the root surfaces 5 and 5 and the insert member 3.
[0041]
Therefore, if the surface shape of the outer surface 8 and the inner surface 9 of the insert member 3 is concave or convex as in the present invention, the surface area of the insert member 3 is increased, and thereby heat energy is efficiently transmitted to the insert member 3. As a result, the B dimension of the insert member 3 can be set to be small accordingly, and more efficient welding is possible.
[0042]
On the other hand, according to experiments, it has been found that if the dimension A of the insert member 3 is set to 2.0 mm, a uniform and smooth convex back bead can be easily obtained during the first layer welding.
[0043]
However, when the dimension A is set to be as thin as 0.5 mm, the melt pool melts frequently during the first layer welding, and it is inevitably necessary to obtain an appropriate back bead shape under these conditions. This is impractical because the welding current has to be set low, which lowers the contact efficiency and narrows the allowable range of welding conditions.
[0044]
Conversely, when the A dimension is set to be as thick as 3.5 mm, the area required for heating increases due to the increase in the thickness of the insert member 3, and the insert member 3 and the root surfaces 5 and 5 are sufficiently fused. It becomes impossible to easily cause welding defects.
[0045]
From these experimental results, if the dimension A of the insert member is set to 1.0 mm to 3.0 mm, a stable and good back bead can be obtained. Among these, the median value of 2.0 mm can be judged as the optimum dimension.
[0046]
Further, a welding bead formed when the insert member 105 is welded to the conventional U-shaped groove-shaped joint portion 102 shown in FIG. 13, and the welding method and insert member according to the present invention shown in FIG. When the weld bead formed by No. 3 is metallurgically compared, the conventional weld bead is a weld metal in which the base material and the weld metal (filler wire and insert member) are mixed at a ratio of about 50%. On the other hand, it was found that about 90% of the weld bead in the present invention is a weld metal, the dilution ratio with the base metal is small, and the mechanical properties and corrosion resistance of the welded portion are superior to the conventional ones. Therefore, also in this respect, it can be said that the welding method and the insert member according to the present invention are superior to the conventional one.
[0047]
In addition, although the said embodiment demonstrated only the example in case a welding base material is a metal piping material, the welding method and insert member which concern on this invention are not restricted to a metal piping material, a metal plate and many other shapes. It can also be widely applied to butt welding of structural materials.
[0048]
【The invention's effect】
As described above, according to the groove butt welding method using the insert member according to the present invention and the insert member used therefor, it is possible to perform continuous welding with high quality and high reliability, while the existing cross-sectional shape of the joint portion. The V-shaped groove shape can be applied without additional machining, reducing the processing cost of the joint and facilitating the tacking work, thereby enabling high-quality groove butt welding using insert members in a wide range of industrial fields at low cost. Can be popularized.
[Brief description of the drawings]
FIG. 1 is a side view showing an example in which a welding method according to the present invention is applied to a metal piping material.
FIGS. 2A and 2B show a first embodiment of the present invention, in which FIG. 2A is an enlarged cross-sectional view showing a portion where a joint portion and an insert member are brought into close contact with each other, and FIG.
FIGS. 3A and 3B show a second embodiment of the present invention, in which FIG. 3A is a partially enlarged sectional view in which a joint portion and an insert member are brought into close contact with each other, and FIG. 3B is a sectional view of an insert member alone;
4A and 4B show a third embodiment of the present invention, in which FIG. 4A is a partially enlarged cross-sectional view in which a joint portion and an insert member are brought into close contact with each other, and FIG. 4B is a cross-sectional view of a single insert member.
5A and 5B show a procedure of a temporary attachment step, in which FIG. 5A is a diagram showing a state in which an insert member is brought into contact with one joint portion, and FIG. 5B is a temporary attachment of the insert member and one joint portion. The figure which shows the state which carried out, (c) is a figure which shows the state which made the insert contact | abut to the joint part of the other c, and was temporarily attached.
6 is a cross-sectional view taken along the line VI-VI in FIG.
FIG. 7 is a schematic explanatory view of TIG welding.
FIG. 8 is a cross-sectional view of a weld bead.
FIG. 9 is a schematic explanatory diagram of MAG welding.
FIG. 10 is a cross-sectional view showing a case where the relationship between the A and B dimensions of the insert member satisfies A> B in a state where the V-shaped groove shape is applied.
FIG. 11 is a cross-sectional view showing a case where the B dimension of the insert member is excessive with respect to the A dimension.
FIG. 12 is a cross-sectional view of a V-shaped groove weld portion that does not use an insert member according to a conventional technique.
FIG. 13 is a cross-sectional view of a U-shaped groove welded part using an insert member showing a conventional technique.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Metal piping material used as base material 2 Joint part 3 Insert member 4 Groove surface 5 Route surface 6 Contact surface 8 The surface which faces the groove surface side of a V type groove joint part 9 The groove back surface of a V type groove joint part Side facing 15 Filler wire (filler rod) during TIG welding
22 Electrode which becomes filler wire (melting rod) during MAG welding

Claims

An insert member forming step for forming an insert member in which the relationship between the thickness A of the contact surface contacting the V-shaped groove joint portion of the base material and the thickness B in the gap joint portion interval direction is A <B <3A; A temporary attachment step of temporarily attaching the insert member to the V-shaped groove joint portion of the base material, and a continuous welding step of continuously welding the V-shaped groove joint portion of the base material and the insert member after the temporary attachment step. And the insert member has a concave surface shape facing the groove surface side of the V-shaped groove joint portion of the base material, and a convex surface shape facing the groove back surface side. A groove butt welding method using a member.

An insert member forming step for forming an insert member in which the relationship between the thickness A of the contact surface contacting the V-shaped groove joint portion of the base material and the thickness B in the gap joint portion interval direction is A <B <3A; A temporary attachment step of temporarily attaching the insert member to the V-shaped groove joint portion of the base material, and a continuous welding step of continuously welding the V-shaped groove joint portion of the base material and the insert member after the temporary attachment step. And the insert member has a convex surface shape facing the groove surface side of the V-shaped groove joint portion of the base material, and a concave surface shape facing the groove back surface side. A groove butt welding method using a member.

An insert member forming step for forming an insert member in which the relationship between the thickness A of the contact surface contacting the V-shaped groove joint portion of the base material and the thickness B in the gap joint portion interval direction is A <B <3A; A temporary attachment step of temporarily attaching the insert member to the V-shaped groove joint portion of the base material, and a continuous welding step of continuously welding the V-shaped groove joint portion of the base material and the insert member after the temporary attachment step. The insert member is characterized in that both the surface shape facing the groove surface side and the surface shape facing the groove back surface side of the V-shaped groove joint portion of the base material are concave. Groove butt welding method using

4. The groove using the insert member according to claim 1, wherein the base material is made of at least one material selected from the group consisting of carbon steel, low alloy steel, and stainless steel. Butt welding method.

In the temporary attaching step of temporarily attaching the insert member to the V-shaped groove joint portion of the base material, after temporarily attaching one side of the insert member to one V-shaped groove joint portion of the base material, 4. The groove butt welding method using the insert member according to claim 1, wherein the side is temporarily attached to the other V-shaped groove joint portion of the base material .

4. The insert member according to claim 1, wherein TIG welding is performed while supplying an appropriate amount of filler wire (filler rod) made of a welding material equivalent to the base material. 5. The groove butt welding method used.

The MAG welding is performed by using a filler wire (melting rod) made of a welding material equivalent to the base material as a consumable electrode and supplying an appropriate amount of the filler wire separately. A groove butt welding method using the insert member according to claim 3 .

The relationship between the thickness A of the contact surface that contacts the V-shaped groove joint portion of the base material and the thickness B in the gap joint portion spacing direction is A <B <3A, and the V-shaped groove of the base material An insert member, wherein a surface shape facing the groove surface side of the joint portion is concave, and a surface shape facing the groove back surface side is convex .

The relationship between the thickness A of the contact surface that contacts the V-shaped groove joint portion of the base material and the thickness B in the gap joint portion spacing direction is A <B <3A, and the V-shaped groove of the base material An insert member characterized in that a surface shape facing the groove surface side of the joint portion is convex and a surface shape facing the groove back surface side is concave .

The relationship between the thickness A of the contact surface that contacts the V-shaped groove joint portion of the base material and the thickness B in the gap joint portion spacing direction is A <B <3A, and the V-shaped groove of the base material An insert member characterized in that a surface shape facing the groove surface side and a surface shape facing the groove back surface side of the joint part are both concave .

11. The insert member according to claim 8, wherein a thickness A of the contact surface is at least 0.5 mm larger than a gap tolerance dimension between groove joint portions of the base material .

11. The insert member according to claim 8, wherein a thickness A of the contact surface is in a range of 1.0 mm to 3.0 mm .

11. The insert member according to claim 8, wherein a thickness A of the contact surface is 2.0 mm .