JP3606294B2

JP3606294B2 - Welding method for joints

Info

Publication number: JP3606294B2
Application number: JP07501096A
Authority: JP
Inventors: 康生村井; 賢司斉藤
Original assignee: Kobe Steel Ltd
Current assignee: Kobe Steel Ltd
Priority date: 1996-03-28
Filing date: 1996-03-28
Publication date: 2005-01-05
Anticipated expiration: 2016-03-28
Also published as: JPH09262689A

Description

【０００１】
【発明の属する技術分野】
本発明は鋼構造物の突合せ継手、角継手、Ｔ継手、十字継手及びはめ込み継手等の溶接に適用される溶接方法に関し、特に、継手の前加工及び組立を低コストで実施することができると共に、継手強度を向上することができる継手の溶接方法に関する。
【０００２】
【従来の技術】
図８は従来のＴ継手の開先部を示す正面図である。図８に示すように、垂直の鋼板１と水平の鋼板２とは垂直に交差するように正面視でＴ字型に組み立てられており、鋼板２の先端面２ｂは、鋼板１の表面に当接している。
【０００３】
図８に示すように組み立てられたＴ継手においては、いわゆる隅肉溶接により部分溶込み溶接を実施するものである。このように、Ｔ継手において、要求される継手強度が比較的低い場合には、一方の部材（鋼板２）の先端面２ｂを他方の部材（鋼板１）の表面に沿うように平坦に切断するのみで、開先を加工することができる。
【０００４】
しかしながら、このような開先部を有するＴ継手においては、部材（鋼板２）の加工は容易であるが、溶接時において、所望の溶込み深さを確保することが困難であるので、高い継手強度を得ることはできない。そこで、一般的に、鋼構造物等においては、突合せ継手、角継手及びＴ継手等を溶接する場合に、良好な溶込み深さを確保し、所望の継手強度を得るために、少なくとも一方の部材に傾斜した切欠きを形成した後、継手を組み立てて溶接している。
【０００５】
図９は従来のＴ継手の他の開先部の形状を示す正面図である。図９に示すＴ継手においては、鋼板４の片端面において、その上面から端面に至るように、傾斜した切欠き４ａが形成されている。そして、図８に示す継手と同様に、垂直の鋼板３と水平の鋼板４とが垂直に交差するように正面視でＴ字型に組み立てられていて、その開先端にレ形の開先部５が形成されていると共に、鋼板４の先端面４ｂが鋼板３の表面に当接している。
【０００６】
このように、継手の開先端に傾斜した切欠き４ａが形成されていると、溶接時において深い溶込みが得られ、これにより、高い継手強度を得ることができる。
【０００７】
【発明が解決しようとする課題】
しかしながら、図９に示すような開先部５を加工する場合、一方の部材（鋼板４）の端面４ｂを、他方の部材（鋼板３）に沿うように平坦に切断する工程と、切欠き４ａを形成する工程との２工程が必要となるという問題点がある。従って、レ形の開先部５を形成するためには、図８に示すように、単に部材（鋼板２）の先端面２ｂを他の部材（鋼板１）に沿うように平坦に切断するのみの場合と比較して、２倍又はそれ以上の加工コストが必要となる。
【０００８】
更に、傾斜した開先部（傾斜開先部）が形成された部材を溶接する場合、単層で十分な適正量の余盛りを得るための溶接条件の設定が比較的困難である。即ち、ルート部（鋼板４の端面４ｂと鋼板３との接触部分）において、溶融金属の溶け落ちが発生しない条件で溶接すると、余盛りが不足することがあり、十分な余盛りを得るための溶接条件を設定すると、溶融金属の溶け落ちが発生しやすくなる。
【０００９】
また、図８に示すように、傾斜した開先部（傾斜開先部）を形成しない場合、一般的に、溶込みを深くするためには、部材間にルートギャップを設けるという方法が適用されている。そこで、均一な適正幅のルートギャップを維持するためには、継手の両部材の組立工程において、ギャップを計測調整しながら仮付け溶接するか、又は部材間にスペーサを配置する必要がある。
【００１０】
しかしながら、このような方法を使用する場合、溶接線が直線でない継手においては、均一にギャップを形成することが困難である。また、部分溶込み状態となったときに、鋼板２の未溶接の先端面２ｂと鋼板１との接触部分が存在しないか、又は接触部分が少なくなるので、溶接によって収縮変形が発生し、寸法精度が低下してしまう。更に、継手部材の組立工程が煩雑になり、スペーサ等を使用する場合には、このような継手部材以外の部材が必要となるため、コストアップとなってしまう。また、継手形状によっては、適切なルートギャップを維持することは極めて困難となる。
【００１１】
本発明はかかる問題点に鑑みてなされたものであって、溶接母材の煩雑な組み立て作業が不要であり、開先部の形成又は部材の組み立て等に必要なコストを上昇させることなく、容易に溶接開先部を加工することができると共に、良好な溶込み深さを得ることができ、これにより、継手強度を高め、優れた寸法精度で溶接することができる継手の溶接方法を提供することを目的とする。
【００１２】
【課題を解決するための手段】
本発明に係る継手の溶接方法は、２つの部材を溶接して接合する継手の溶接方法において、前記２つの部材の一方の部材は板状部材であり、この板状部材の端面に凹凸面を形成して、前記凹凸面を他方の部材に当接させて前記凹凸面と平面からなる開先を溶接するものであり、前記凹凸面は凹部及び凸部が一定間隔で交互に形成されているものであって、凹部の空間体積が凸部の体積の２倍未満のとき、前記板状部材の板厚をｔ（ｍｍ）とすると、隣接する凸部間の距離を２乃至２０ｍｍ、凹部の深さを（０．０８×ｔ）乃至（０．６×ｔ）ｍｍとし、凹部の空間体積が凸部の体積の２倍以上であるとき、凸部の幅を５ｍｍ以下、凹部の深さを０．５乃至３ｍｍ、凸部間の距離を５０ｍｍ以下とすることを特徴とする。
【００１４】
また、板状部材の端面に前記板状部材に対して直交する方向に複数本の溝状の凹部を形成し、前記凹部により凹凸面が形成されていてもよい。更に、この溝状の凹部は板状部材に直交する方向に対して６０°以下に傾斜して形成されていることが好ましい。
【００１５】
更にまた、前記一方の部材は、前記凹凸面からこれに隣接する面に至る傾斜した切欠きが形成されていてもよい。
【００１７】
本発明方法においては、２つの部材の少なくとも一方の部材の開先端に凹凸面を形成し、その凹凸面を他方の部材に当接させて溶接するので、凹部が局部的なルートギャップとなり、仮溶接又はスペーサ等によりルートギャップを維持する必要が無く、溶接のための部材の組立が容易になる。また、凹凸面の凸部は熱容量が小さく、溶接熱により比較的容易に溶融するので、凹部が有するルートギャップとしての作用により、溶込み深さを深くすることができると共に、凸部の存在により溶融金属の溶け落ちを防止することができ、これにより、継手強度を向上させることができる。
【００１８】
更に、凹凸面の形成と部材の切断とを同時に実施することができるので、低コストで開先部を加工することができる。
【００１９】
更にまた、部分溶込み溶接を実施する場合、未溶接部分が他方の部材に当接しているので、溶接収縮を少なくすることができ、これにより、溶接後の寸法精度を高めることができる。
【００２０】
また、本発明方法において、板状部材の端面に凹凸を形成し、この端面を他方の部材に当接させてＴ継手を組み立てて溶接すると、凹凸面の凹凸の加工及び継手の組立が容易になり、凹凸面から隣接する面に至る切欠きを形成すると、溶接時において深い溶込みが得られる。
【００２１】
更に、板状部材の表面から裏面に至る溝状の凹部を板状部材の端面に形成すると、凹凸面を更に一層容易に加工することができ、この溝状の凹部を板状部材に直交する方向に対して傾斜させて形成すると、溶融金属の溶け落ちを防止する効果が高められる。この傾斜角度は板状部材に直交する方向に対して６０°を超えると、溝状の凹部の加工が困難になると共に、溶融金属の溶け落ちを防止する効果はそれ以上向上しなくなる。従って、板状部材の表面から裏面に至る溝状の凹部を傾斜させて形成する場合、その傾斜角度は板状部材に直交する方向に対して６０°以下であることが好ましい。
【００２２】
更にまた、凹部及び凸部が一定間隔で交互に形成されていて、凹部の空間体積が凸部の体積の２倍未満である場合、隣接する凸部間の距離が２ｍｍ未満であると、加工が煩雑になるので好ましくない。一方、凸部間の距離が２０ｍｍを超えると、溶け落ちが発生しやすくなる。
【００２３】
また、凹部の深さが板状部材の板厚ｔ（ｍｍ）に対して（０．０８×ｔ）ｍｍ未満であると、所望の溶込み深さを得ることができず、凹部の深さが（０．６×ｔ）ｍｍを超えると、溶融金属の溶け落ちが発生する。従って、凹部の空間体積が凸部の体積の２倍未満のとき、隣接する凸部間の距離を２乃至２０ｍｍ、凹部の深さを（０．０８×ｔ）乃至（０．６×ｔ）ｍｍとすることが好ましい。
【００２４】
一方、凹部及び凸部が一定間隔で交互に形成されていて、凹部の空間体積が凸部の体積の２倍以上であると共に、凸部の幅が５ｍｍ以下である場合、隣接する凸部間の距離が５０ｍｍを超えると、溶融金属の溶け落ちが発生しやすくなる。
【００２５】
また、凹部の深さが０．５ｍｍ未満であると、所望の溶込み深さを得ることができず、凹部の深さが３ｍｍを超えると、溶融金属の溶け落ちが発生しやすくなる。従って、凹部の空間体積が凸部の体積の２倍以上、凸部の幅が５ｍｍ以下であるとき、凹部の深さを０．５乃至３ｍｍ、凸部間の距離を５０ｍｍ以下とすることが好ましい。
【００２６】
【発明の実施の形態】
以下、本発明の実施例について添付の図面を参照して具体的に説明する。
【００２７】
図１（ａ）は本発明の実施例に係る継手の溶接方法を説明するための継手を示す斜視図であり、（ｂ）はその平面図、（ｃ）はその正面図である。
【００２８】
図１に示すように、板状部材１２の一方の端面には、板状部材１２の表面から裏面に延びるように、等間隔に複数の溝状の凹部１２ａが形成されており、この凹部１２ａを形成することにより、隣接する凹部１２ａ間に凸部１２ｂが形成されている。従って、図１（ｂ）に示すように、板状部材１２の一方の端面においては、凹部１２ａと凸部１２ｂとが交互に配置され、平面視で波形の凹凸面１２ｃが形成されている。そして、垂直の板状部材１１の表面に水平の板状部材１２の凹凸面１２ｃが当てられ、板状部材１１と板状部材１２とが垂直に交差するように正面視でＴ字型に組み立てられている。
【００２９】
このように継手１０を組み立てた後、板状部材１２の凹凸面１２ｃに沿って溶接する。そうすると、板状部材１２の凸部１２ｂは熱容量が小さいので、溶接熱により比較的容易に溶融する。また、凸部１２ｂが板状部材１１の表面に接触するか又は近接し、凹部１２ａが局部的に板状部材１１と１２とのルートギャップとしての役割を果たすので、深い溶込みを得ることができる。即ち、凹部１２ａと凸部１２ｂとの相互効果により、所望の溶込み深さ及び所望の余盛りを得ることができる。
【００３０】
また、本実施例においては、板状部材１２の一方の端面の切断加工と凹部の形成とを同時に実施することができるので、１工程のみで所望の開先を得ることができ、開先の加工コストを低くすることができる。更に、部材の組立が容易であり、スペーサ等が不要であるので、そのためのコストアップを防止することができる。
【００３１】
更にまた、ルート部（板状部材１２の凸部１２ｂと板状部材１１との接触部分）において、未溶接部分を極めて小さくし、完全溶込み溶接に近い溶接部を得ようとする場合においては、凸部１２ｂが存在することにより、溶融金属の溶け落ちの発生を防止することができる。一方、部分溶込み溶接をする場合、凸部１２ｂにおける未溶接部分が板状部材１１に当接しているので、溶接による収縮変形が小さくなる。
【００３２】
本実施例においては、Ｔ継手の例について示したが、例えば、突合せ継手、角継手、十字継手及びはめ込み継手においても同様の効果を得ることができる。また、レ形及びＶ形等の傾斜開先部を有する継手においても、両部材の接触面（ルート面）に同様の加工を施すことができる。
【００３３】
【実施例】
以下、本発明に係る溶接方法を使用して得られた溶接継手の実施例についてその比較例と比較して具体的に説明する。
【００３４】
先ず、本発明に係る溶接方法及び従来の溶接方法によりＴ継手を溶接し、溶込み深さ比較試験を実施した。
【００３５】
図２は溶込み深さ比較試験に使用したＴ継手の形状及びサイズを示す正面図である。また、図３（ａ）は本発明の実施例に係る溶接方法において使用した板状部材の形状及びサイズを示す平面図であり、（ｂ）はその正面図である。
【００３６】
比較例としては、図２に示すように、板厚が１４ｍｍの板状部材１３と板厚が１２ｍｍである板状部材１４とを準備し、垂直に配置された板状部材１３と水平に配置された板状部材１４とが垂直に交差するように、板状部材１３の表面に板状部材１４の平坦な端面１４ａを当てて組み立てたＴ継手を使用した。なお、板状部材１４は、その上面が板状部材１３の端面１３ａから１２ｍｍの位置になるように配置した。
【００３７】
また、実施例としては、板状部材１４の代わりに波形の凹凸面１５ｃを有する板状部材１５を使用した。即ち、図３に示すように、板状部材１５は、ガス切断によって、一方の端面に、板状部材１５の表面から裏面に延びるように、等間隔に複数本の溝状の凹部１５ａ及び凸部１５ｂを交互に形成したものであり、板状部材１４の表面に板状部材１５の凸部１５ｂを当接させて継手を組み立てた。本実施例においては、板状部材１５の板厚を１２ｍｍとし、隣接する凸部１５ｂの間隔を５ｍｍ、各凹部１５ａの深さを２．５ｍｍとした。
【００３８】
このような２種類のＴ継手に対して同一の溶接条件によって溶接し、溶接後に、溶接部から断面マクロを採取し、未溶接部分のルート厚さを測定することにより、溶込み深さを評価した。但し、溶接は直径が１．４ｍｍのワイヤを使用し、自動ＣＯ_２溶接とした。溶接条件を下記表１に示し、評価結果を下記表２に示す。
【００３９】
【表１】

【００４０】
【表２】

【００４１】
上記表１及び２に示すように、本実施例方法によって溶接すると、いずれの溶接条件においても、比較例と比較して、未溶接部分のルート長さが減少した。即ち、溶込み深さが増大し、良好な溶接継手を得ることができた。
【００４２】
次いで、本発明に係る溶接方法及び従来の溶接方法によりＴ継手を溶接し、曲げ疲労試験を実施した。この曲げ疲労試験においては、図３に示す板状部材１５を適用した継手を実施例Ｎｏ．７とし、図２に示す形状及びサイズの継手を比較例Ｎｏ．８、傾斜開先部を有するＴ継手を比較例Ｎｏ．９とした。
【００４３】
図４は曲げ疲労試験に使用した傾斜開先部を有するＴ継手の形状及びサイズを示す正面図である。図４に示すように、板状部材１７は一方の端面において、その上面から端面に至るように、傾斜した切欠き１７ａを形成した。そして、板厚が１４ｍｍである板状部材１６を準備し、板状部材１６と板状部材１７とが垂直に交差するように、切欠き１７ａにより形成された板状部材１７の端面１７ｂを、板状部材１６の表面に当てるように正面視でＴ字型に組み立てた。従って、板状部材１６と板状部材１７との間の切欠き１７ａの部分は、レ形の傾斜開先部１８となっている。
【００４４】
この曲げ疲労試験において使用した図４に示す継手においては、レ形の傾斜開先部１８の開先角度を４５°とし、板状部材１７の板厚を１２ｍｍ、先端面１７ｂの板厚方向の幅を３ｍｍとした。
【００４５】
このような３種類の継手を溶接して、曲げ疲労試験用の試験片とし、疲労限を比較した。但し、溶接条件として、実施例Ｎｏ．７及び比較例Ｎｏ．８については、上記表１に示す溶接条件記号Ｃの条件を使用して溶接し、比較例Ｎｏ．９については、溶融金属の溶け落ちを考慮して２層仕上げとした。比較例Ｎｏ．９の継手に対する溶接時の溶接条件を下記表３に示す。
【００４６】
【表３】

【００４７】
図５（ａ）は曲げ疲労試験用の試験片の形状及びサイズを示す側面図であり、（ｂ）はその正面図である。図５においては、図２及び４の板状部材１３及び１６を部材Ｄとし、板状部材１４、１５及び１７を部材Ｅとして説明する。
【００４８】
前述の如く、部材Ｄと部材Ｅとは垂直に交差するようにＴ字型に組み立てられて溶接されており、開先部には溶接金属２０が形成されている。部材Ｄ及びＥは、その長手方向の長さを１２０ｍｍ、幅を５０ｍｍとした。また、部材Ｄには、４カ所に、これを貫通する固定孔１９が設けられており、これらの固定孔１９に固定ジグ（図示せず）を挿入し、この固定ジグを固定器（図示せず）に締着することにより部材Ｄが固定されるようになっている。更に、部材Ｅには、部材Ｄ側の端面から２０ｍｍ離れた位置において、板幅中央の表面及び裏面に、歪みゲージ２３が貼付されている。
【００４９】
このように作製された試験片において、部材Ｄを固定した後、部材Ｅの溶接されていない端部２５に対して、部材Ｄに平行方向に繰り返し応力を印加して、歪みゲージ２３にかかる歪から繰り返し曲げ応力を設定し、応力振幅１６ｋｇｆ／ｍｍ^２における破断繰り返し数を比較した。この曲げ疲労試験の評価結果を下記表４に示す。
【００５０】
【表４】

【００５１】
上記表４に示すように、実施例Ｎｏ．７は比較例と比較して、破断繰り返し数が増加した。即ち、本発明方法により溶接することによって、溶接継手の曲げ疲労強度を高めることができる。
【００５２】
次いで、軟鋼製の２枚の板状部材を準備し、一方の板状部材の端面に種々の幅及び高さを有する凹凸面を形成した後、この凹凸面を他方の板状部材の端面に当てて継手を組み立て、この突合せ継手を溶接してビードの外観及び溶込み状況を評価した。但し、凹凸面においては、凹部の空間体積が凸部の体積の２倍未満となるように形成した。また、板状部材は１２ｍｍと２５ｍｍの２種の板厚のものを使用し、板厚が１２ｍｍの板状部材についてはＭＡＧ溶接、板厚が２５ｍｍの板状部材についてはサブマージアーク溶接により溶接した。
【００５３】
このときの溶接条件を下記表５に示し、板厚が１２ｍｍの板状部材におけるビードの外観及び溶込み形状の評価結果を下記表６、板厚が２５ｍｍの板状部材におけるビードの外観及び溶込み形状の評価結果を下記表７に示す。なお、下記表６及び７において、○（合格）は平坦な開先の突合せ溶接の溶込み深さと比較して、板厚の１０％以上溶込み深さが増大すると共に、表面にアンダーフィルが発生せず、溶融金属の溶け落ちが発生しなかったものである。また、△は溶接の位置によって不合格の部分があったもの、×は溶込み深さが合格の基準を満足しなかったもの、××は溶融金属の溶け落ちが発生したものを示し、−は凹凸面を加工するための工程が煩雑になるため、実施しなかったことを示す。
【００５４】
【表５】

【００５５】
【表６】

【００５６】
【表７】

【００５７】
上記表６に示すように、板状部材の板厚が１２ｍｍの場合、凹部の深さが０．５ｍｍ以上であると共に、ピッチが２ｍｍ以上であると、溶込み深さが増大し、凹部の深さが１０ｍｍ以上になると、溶融金属の溶け落ちが発生した。
【００５８】
一方、上記表７に示すように、板状部材の板厚が２５ｍｍの場合、凹部の深さが１５ｍｍの範囲まで良好な溶接継手を得ることができるピッチが存在した。また、ピッチが３０ｍｍ以上になると、溶接線方向において溶け込み深さが大きく変動した。
【００５９】
これらの結果より、良好な溶接継手を得るための凹部の深さは板厚に依存し、凹凸面における凹部の深さが部材の板厚の６０％までであると、所望の溶込み深さが得られると共に、溶融金属の溶け落ちを防止することができる。
【００６０】
更に、凹凸面の形状を変化させた板状部材を準備し、この凹凸面を他の板状部材に当接させて継手を組み立て、この突合せ継手を溶接することによって、ビードの外観及び溶込み状況を評価した。なお、凹凸面を形成する板状部材としては１２ｍｍと２５ｍｍの２種の板厚のものを準備し、板厚が１２ｍｍの板状部材についてはＭＡＧ溶接、板厚が２５ｍｍの板状部材についてはサブマージアーク溶接を適用し、上記表５に示す溶接条件に準じて溶接した。
【００６１】
図６（ａ）は本実施例において使用した板状部材の形状を示す平面図であり、（ｂ）はその正面図である。図６に示すように、板状部材２１の端面には板状部材２１の表面から裏面に至る凸部２１ｂが等間隔に形成されていて、隣接する凸部２１ｂ間に幅広の凹部２１ａが形成されている。
【００６２】
図６に示すような形状の凹凸面を有する板状部材２１を使用した場合、凹部２１ａの深さＤが０．５乃至３ｍｍであるとき、凸部の幅Ｗを５ｍｍ以下に設定すると、隣接する凸部間の距離Ｐが５０ｍｍ程度であっても、ビードの外観及び溶込み状況の評価結果が合格となった。
【００６３】
図７は本実施例において使用した板状部材の他の形状を示す斜視図である。図７に示すように、板状部材２２は、その端面に板状部材２２の上面から裏面に延びるように、等間隔に複数本の溝状の凹部２２ａが形成されており、この凹部２２ａを形成することにより、隣接する凹部２２ａ間に凸部２２ｂが形成されている。従って、板状部材２２の端面においては、凹部２２ａと凸部２２ｂとが交互に配置されて波形となっているが、図３に示す板状部材１５と異なり、凹部２２ａ及び凸部２２ｂは板状部材２２に直交する方向に対して傾斜して形成されている。
【００６４】
この傾斜した凹部２２ａの傾斜角度を２０乃至７０°の範囲で変化させて種々の溶接電流で溶接した結果、従来の平坦な開先部を溶接した場合と比較して、深い溶込みを得ることができた。また、本実施例は溝状の凹部２２ａを板状部材に直交する方向に形成した場合（傾斜角０°）と比較して、溶接電流を高くしても、溶融金属の溶け落ちが発生しにくくなった。
【００６５】
従って、このような形状の凹凸面を有する板状部材２２は、完全溶込みに近い溶込みが要求される継手に対して有効である。但し、溝状の凹部２２ａの傾斜角が６０°を超えると、凹凸面の加工が困難になると共に、溶融金属の溶け落ちを防止する効果は向上しなくなる。
【００６６】
【発明の効果】
以上詳述したように、本発明によれば、継手の少なくとも一方の部材の開先端に凹凸面を形成しているので、傾斜開先を形成することなく深い溶込みで継手強度が高い溶接継手を得ることができると共に、溶融金属の溶け落ちを防止することができ、これにより、容易に溶接のための加工及び組立を低コストで実施することができる。また、凸部が他方の部材に当接しているので、部分溶込み溶接の場合でも溶接収縮を防止することができ、溶接後の寸法精度を高めることができる。更に、この凹凸面を板状部材の端面に形成し、板状部材の表面から裏面に至るように溝状の凹部を形成すると、更に一層加工及び組立が容易になり、凹凸面における凹部の深さ及び凸部間の距離を適切に規制することにより、更に一層良好な溶接継手を得ることができると共に、継手強度を向上させることができる。
【図面の簡単な説明】
【図１】（ａ）は本発明の実施例に係る継手の溶接方法を説明するための継手を示す斜視図であり、（ｂ）はその平面図、（ｃ）はその正面図である。
【図２】溶込み深さ比較試験に使用したＴ継手の形状及びサイズを示す正面図である。
【図３】（ａ）は本発明の実施例に係る溶接方法において使用した板状部材の形状及びサイズを示す平面図であり、（ｂ）はその正面図である。
【図４】曲げ疲労試験に使用した傾斜開先部を有するＴ継手の形状及びサイズを示す正面図である。
【図５】（ａ）は曲げ疲労試験用の試験片の形状及びサイズを示す側面図であり、（ｂ）はその正面図である。
【図６】（ａ）は本実施例において使用した板状部材の形状を示す平面図であり、（ｂ）はその正面図である。
【図７】本実施例において使用した板状部材の他の形状を示す斜視図である。
【図８】従来のＴ継手の開先形状を示す正面図である。
【図９】従来のＴ継手の他の開先形状を示す正面図である。
【符号の説明】
１、２、３、４；鋼板
４ａ；切欠き
５、１８；開先部
１０；継手
１１、１２、１３、１４、１５、１６、１７、２１、２２；板状部材
１２ａ、１５ａ、２１ａ、２２ａ；凹部
１２ｂ、１５ｂ、２１ｂ、２２ｂ；凸部
１９；固定孔
２０；溶接金属
２３；歪みゲージ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a welding method applied to welding of butt joints, square joints, T joints, cruciform joints, inset joints, and the like of steel structures, and in particular, it is possible to perform joint pre-processing and assembly at low cost. The present invention also relates to a joint welding method capable of improving joint strength.
[0002]
[Prior art]
FIG. 8 is a front view showing a groove portion of a conventional T joint. As shown in FIG. 8, the vertical steel plate 1 and the horizontal steel plate 2 are assembled in a T shape so as to intersect perpendicularly, and the front end surface 2 b of the steel plate 2 contacts the surface of the steel plate 1. It touches.
[0003]
In the T joint assembled as shown in FIG. 8, partial penetration welding is performed by so-called fillet welding. Thus, in the T joint, when the required joint strength is relatively low, the front end surface 2b of one member (steel plate 2) is cut flat so as to be along the surface of the other member (steel plate 1). Only the groove can be processed.
[0004]
However, in a T-joint having such a groove portion, the processing of the member (steel plate 2) is easy, but it is difficult to ensure a desired penetration depth during welding. You cannot get strength. Therefore, in general, in a steel structure or the like, when welding a butt joint, a corner joint, a T joint, etc., in order to secure a good penetration depth and obtain a desired joint strength, After forming the inclined notch in the member, the joint is assembled and welded.
[0005]
FIG. 9 is a front view showing the shape of another groove portion of a conventional T joint. In the T joint shown in FIG. 9, an inclined notch 4 a is formed on one end surface of the steel plate 4 so as to reach the end surface from the upper surface. And, like the joint shown in FIG. 8, the vertical steel plate 3 and the horizontal steel plate 4 are assembled in a T shape in front view so as to intersect perpendicularly, and a cleated groove portion is formed at the open tip. 5 is formed, and the front end surface 4 b of the steel plate 4 is in contact with the surface of the steel plate 3.
[0006]
As described above, when the inclined notch 4a is formed at the open tip of the joint, deep penetration can be obtained during welding, and thereby high joint strength can be obtained.
[0007]
[Problems to be solved by the invention]
However, when machining the groove portion 5 as shown in FIG. 9, a step of cutting the end surface 4b of one member (steel plate 4) flatly along the other member (steel plate 3), and a notch 4a. There is a problem that two steps, that is, the step of forming the film are required. Therefore, in order to form the groove-shaped groove portion 5, as shown in FIG. 8, the tip surface 2b of the member (steel plate 2) is simply cut flatly along the other member (steel plate 1). Compared with the case of, the processing cost of 2 times or more is needed.
[0008]
Furthermore, when welding the member in which the inclined groove part (inclined groove part) was formed, it is comparatively difficult to set the welding conditions for obtaining a sufficient amount of surplus with a single layer. That is, in the root portion (contact portion between the end surface 4b of the steel plate 4 and the steel plate 3), when welding is performed under a condition that does not cause the molten metal to be burned out, the surplus may be insufficient, and a sufficient surplus is obtained. When the welding conditions are set, the molten metal is likely to be burned out.
[0009]
In addition, as shown in FIG. 8, when an inclined groove portion (inclined groove portion) is not formed, generally, a method of providing a root gap between members is applied in order to deepen the penetration. ing. Therefore, in order to maintain a route gap having a uniform and appropriate width, it is necessary to perform temporary welding while measuring and adjusting the gap in the assembly process of both members of the joint, or to arrange a spacer between the members.
[0010]
However, when such a method is used, it is difficult to form a uniform gap in a joint where the weld line is not a straight line. Further, when a partial penetration state occurs, there is no contact portion between the unwelded tip surface 2b of the steel plate 2 and the steel plate 1, or the contact portion is reduced, so that shrinkage deformation occurs due to welding, Accuracy will be reduced. Furthermore, the assembly process of the joint member becomes complicated, and when a spacer or the like is used, a member other than such a joint member is required, resulting in an increase in cost. Further, depending on the joint shape, it is extremely difficult to maintain an appropriate route gap.
[0011]
The present invention has been made in view of such problems, and does not require a complicated assembly operation of the welding base material, and can be easily performed without increasing the cost necessary for forming the groove portion or assembling the members. It is possible to process a weld groove portion and to obtain a good penetration depth, thereby improving the joint strength and providing a joint welding method capable of welding with excellent dimensional accuracy. For the purpose.
[0012]
[Means for Solving the Problems]
The joint welding method according to the present invention is a joint welding method in which two members are welded together, and one of the two members is a plate-like member, and an uneven surface is formed on an end surface of the plate-like member. Forming the concave / convex surface with the other member and welding a groove formed of the concave / convex surface and the flat surface, and the concave / convex surface has alternating concave and convex portions formed at regular intervals. When the space volume of the concave portion is less than twice the volume of the convex portion, when the plate thickness of the plate-like member is t (mm), the distance between the adjacent convex portions is 2 to 20 mm, the depth and (0.08 × t) to (0.6 × t) mm, when the spatial volume of the recesses is more than twice the volume of the convex portion, 5 mm or less the width of the convex portion, the depth of the recess The thickness is 0.5 to 3 mm, and the distance between the convex portions is 50 mm or less.
[0014]
In addition, a plurality of groove-shaped recesses may be formed on the end surface of the plate-like member in a direction orthogonal to the plate-like member, and an uneven surface may be formed by the recess. Furthermore, it is preferable that the groove-shaped recess is formed at an angle of 60 ° or less with respect to the direction orthogonal to the plate-like member.
[0015]
Further, the one member may be formed with an inclined notch extending from the uneven surface to a surface adjacent thereto.
[0017]
In the method of the present invention, an uneven surface is formed at the open tip of at least one of the two members, and the uneven surface is brought into contact with the other member and welded. There is no need to maintain the root gap by welding or spacers, and assembly of members for welding is facilitated. Moreover, since the convex part of the uneven surface has a small heat capacity and melts relatively easily by welding heat, the depth of penetration can be increased by the action of the root gap of the concave part, and the presence of the convex part. It is possible to prevent the molten metal from being burned out, thereby improving the joint strength.
[0018]
Furthermore, since the formation of the uneven surface and the cutting of the member can be performed at the same time, the groove portion can be processed at low cost.
[0019]
Furthermore, when carrying out partial penetration welding, since the unwelded part is in contact with the other member, welding shrinkage can be reduced, and thereby the dimensional accuracy after welding can be increased.
[0020]
Further, in the method of the present invention, when the unevenness is formed on the end face of the plate-like member, the end face is brought into contact with the other member, and the T joint is assembled and welded, the unevenness of the uneven face and the assembly of the joint are facilitated. If a notch extending from the uneven surface to the adjacent surface is formed, deep penetration can be obtained during welding.
[0021]
Furthermore, when a groove-shaped recess extending from the front surface to the back surface of the plate-shaped member is formed on the end surface of the plate-shaped member, the uneven surface can be further easily processed, and the groove-shaped recess is orthogonal to the plate-shaped member. When it is formed to be inclined with respect to the direction, the effect of preventing the molten metal from being melted is enhanced. If this inclination angle exceeds 60 ° with respect to the direction orthogonal to the plate-like member, it becomes difficult to process the groove-shaped recess, and the effect of preventing the molten metal from being burned out is not improved any more. Therefore, when the groove-shaped concave portion extending from the front surface to the back surface of the plate member is formed to be inclined, the inclination angle is preferably 60 ° or less with respect to the direction orthogonal to the plate member.
[0022]
Furthermore, when the concave portions and the convex portions are alternately formed at regular intervals, and the space volume of the concave portions is less than twice the volume of the convex portions, the distance between adjacent convex portions is less than 2 mm. Is not preferable because it becomes complicated. On the other hand, if the distance between the convex portions exceeds 20 mm, the melt-off easily occurs.
[0023]
Further, if the depth of the recess is less than (0.08 × t) mm with respect to the plate thickness t (mm) of the plate-like member, a desired penetration depth cannot be obtained, and the depth of the recess When the thickness exceeds (0.6 × t) mm, molten metal melts off. Accordingly, when the space volume of the concave portion is less than twice the volume of the convex portion, the distance between adjacent convex portions is 2 to 20 mm, and the depth of the concave portion is (0.08 × t) to (0.6 × t). It is preferable to use mm.
[0024]
On the other hand, when the concave portions and the convex portions are alternately formed at regular intervals, and the space volume of the concave portions is more than twice the volume of the convex portions, and the width of the convex portions is 5 mm or less, between adjacent convex portions If the distance exceeds 50 mm, the molten metal is likely to be melted down.
[0025]
Moreover, when the depth of the recess is less than 0.5 mm, a desired penetration depth cannot be obtained, and when the depth of the recess exceeds 3 mm, the molten metal is likely to be melted down. Therefore, when the space volume of the recesses is at least twice the volume of the projections and the width of the projections is 5 mm or less, the depth of the recesses is 0.5 to 3 mm, and the distance between the projections is 50 mm or less. preferable.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[0027]
FIG. 1A is a perspective view showing a joint for explaining a joint welding method according to an embodiment of the present invention, FIG. 1B is a plan view thereof, and FIG. 1C is a front view thereof.
[0028]
As shown in FIG. 1, a plurality of groove-like recesses 12a are formed at equal intervals on one end face of the plate-like member 12 so as to extend from the front surface of the plate-like member 12 to the back surface. As a result, the convex portion 12b is formed between the adjacent concave portions 12a. Accordingly, as shown in FIG. 1B, the concave portions 12a and the convex portions 12b are alternately arranged on one end surface of the plate-like member 12, and a corrugated concave and convex surface 12c is formed in plan view. Then, the uneven surface 12c of the horizontal plate-like member 12 is applied to the surface of the vertical plate-like member 11, and the plate-like member 11 and the plate-like member 12 are assembled into a T shape in front view so as to intersect vertically. It has been.
[0029]
After assembling the joint 10 in this way, welding is performed along the uneven surface 12 c of the plate-like member 12. If it does so, since the convex part 12b of the plate-shaped member 12 has a small heat capacity, it fuse | melts comparatively easily with welding heat. Moreover, since the convex part 12b contacts or adjoins the surface of the plate-shaped member 11, and the concave part 12a locally serves as a root gap between the plate-shaped

members

11 and 12, a deep penetration can be obtained. it can. That is, a desired penetration depth and a desired surplus can be obtained by the mutual effect of the concave portion 12a and the convex portion 12b.
[0030]
Further, in this embodiment, since cutting of one end surface of the plate-like member 12 and formation of the recess can be performed at the same time, a desired groove can be obtained in only one step, and the groove Processing costs can be reduced. Furthermore, since the assembly of the members is easy and no spacer or the like is required, an increase in cost can be prevented.
[0031]
Furthermore, in the case of trying to obtain a weld portion close to complete penetration welding by making the unwelded portion extremely small in the root portion (contact portion between the convex portion 12b of the plate member 12 and the plate member 11). The presence of the convex portion 12b can prevent the molten metal from being melted. On the other hand, when performing partial penetration welding, since the unwelded part in the convex part 12b is contact | abutting to the plate-shaped member 11, the shrinkage deformation by welding becomes small.
[0032]
In the present embodiment, an example of a T joint has been described, but the same effect can be obtained in, for example, a butt joint, a corner joint, a cross joint, and a fitting joint. Further, even in a joint having an inclined groove portion such as a L shape and a V shape, the same processing can be performed on the contact surfaces (root surfaces) of both members.
[0033]
【Example】
Examples of welded joints obtained by using the welding method according to the present invention will be specifically described below in comparison with comparative examples.
[0034]
First, a T joint was welded by the welding method according to the present invention and the conventional welding method, and a penetration depth comparison test was performed.
[0035]
FIG. 2 is a front view showing the shape and size of the T joint used in the penetration depth comparison test. Moreover, Fig.3 (a) is a top view which shows the shape and size of the plate-shaped member used in the welding method based on the Example of this invention, (b) is the front view.
[0036]
As a comparative example, as shown in FIG. 2, a plate-like member 13 having a plate thickness of 14 mm and a plate-like member 14 having a plate thickness of 12 mm are prepared and arranged horizontally with the plate-like member 13 arranged vertically. A T-joint assembled by applying the flat end surface 14a of the plate-like member 14 to the surface of the plate-like member 13 so that the formed plate-like member 14 intersects perpendicularly was used. The plate-like member 14 was arranged so that the upper surface thereof was positioned 12 mm from the end surface 13a of the plate-like member 13.
[0037]
Further, as an example, a plate-like member 15 having a corrugated uneven surface 15 c was used instead of the plate-like member 14. That is, as shown in FIG. 3, the plate-like member 15 has a plurality of groove-like recesses 15a and projections at equal intervals so as to extend from one surface to the other side by gas cutting. The portions 15b are alternately formed, and the joint is assembled by bringing the convex portions 15b of the plate-like member 15 into contact with the surface of the plate-like member 14. In the present embodiment, the plate-like member 15 has a thickness of 12 mm, the interval between adjacent convex portions 15 b is 5 mm, and the depth of each concave portion 15 a is 2.5 mm.
[0038]
Welding these two types of T-joints under the same welding conditions, and after welding, taking a cross-sectional macro from the welded part and measuring the root thickness of the unwelded part to evaluate the penetration depth did. However, welding used a wire with a diameter of 1.4 mm, and automatic CO ₂ welding was used. The welding conditions are shown in Table 1 below, and the evaluation results are shown in Table 2 below.
[0039]
[Table 1]

[0040]
[Table 2]

[0041]
As shown in Tables 1 and 2, when welding was performed by the method of this example, the root length of the unwelded portion was reduced as compared with the comparative example under any welding conditions. That is, the penetration depth was increased and a good weld joint could be obtained.
[0042]
Next, a T-joint was welded by a welding method according to the present invention and a conventional welding method, and a bending fatigue test was performed. In this bending fatigue test, a joint to which the plate-like member 15 shown in FIG. 7 and the joint having the shape and size shown in FIG. 8, T-joint having an inclined groove part was compared with Comparative Example No. It was set to 9.
[0043]
FIG. 4 is a front view showing the shape and size of a T-joint having an inclined groove part used in a bending fatigue test. As shown in FIG. 4, the plate-like member 17 has an inclined notch 17 a formed on one end face so as to reach the end face from the upper surface. Then, a plate-like member 16 having a plate thickness of 14 mm is prepared, and an end surface 17b of the plate-like member 17 formed by the notch 17a is formed so that the plate-like member 16 and the plate-like member 17 intersect vertically. The plate-shaped member 16 was assembled in a T shape so as to be in contact with the surface. Therefore, the notch 17 a between the plate-like member 16 and the plate-like member 17 forms a re-shaped inclined groove portion 18.
[0044]
In the joint shown in FIG. 4 used in this bending fatigue test, the groove angle of the inclined inclined groove portion 18 is set to 45 °, the plate thickness of the plate-like member 17 is 12 mm, and the thickness direction of the tip end surface 17b is in the plate thickness direction. The width was 3 mm.
[0045]
These three types of joints were welded to make a specimen for a bending fatigue test, and the fatigue limits were compared. However, as the welding conditions, Example No. 7 and Comparative Example No. No. 8 was welded using the conditions of welding condition symbol C shown in Table 1 above. For No. 9, a two-layer finish was taken in consideration of the molten metal being burned off. Comparative Example No. Table 3 shows the welding conditions for welding the 9 joint.
[0046]
[Table 3]

[0047]
Fig.5 (a) is a side view which shows the shape and size of the test piece for a bending fatigue test, (b) is the front view. In FIG. 5, the plate-

like members

13 and 16 of FIGS. 2 and 4 are described as a member D, and the plate-

like members

14, 15, and 17 are described as a member E.
[0048]
As described above, the member D and the member E are assembled and welded in a T shape so as to intersect perpendicularly, and the weld metal 20 is formed in the groove portion. The members D and E had a length in the longitudinal direction of 120 mm and a width of 50 mm. The member D is provided with fixing holes 19 penetrating therethrough at four locations. A fixing jig (not shown) is inserted into the fixing holes 19, and the fixing jig is fixed to a fixing device (not shown). The member D is fixed by being fastened. Further, a strain gauge 23 is attached to the member E on the front and back surfaces in the center of the plate width at a position 20 mm away from the end surface on the member D side.
[0049]
In the test piece manufactured in this way, after fixing the member D, a stress applied to the strain gauge 23 is repeatedly applied in a direction parallel to the member D to the unwelded end portion 25 of the member E. From the above, repeated bending stresses were set, and the number of repeated fractures at a stress amplitude of 16 kgf / mm ² was compared. The evaluation results of this bending fatigue test are shown in Table 4 below.
[0050]
[Table 4]

[0051]
As shown in Table 4 above, Example No. 7 increased the number of repetitions of breakage as compared with the comparative example. That is, the bending fatigue strength of the welded joint can be increased by welding by the method of the present invention.
[0052]
Next, two plate members made of mild steel are prepared, and an uneven surface having various widths and heights is formed on the end surface of one plate member, and then this uneven surface is used as the end surface of the other plate member. The joint was assembled by contact, and the butt joint was welded to evaluate the appearance and penetration of the bead. However, the concave / convex surface was formed so that the space volume of the concave portion was less than twice the volume of the convex portion. In addition, the plate-like members were used with two plate thicknesses of 12 mm and 25 mm, the plate-like members having a plate thickness of 12 mm were welded by MAG welding, and the plate-like members having a plate thickness of 25 mm were welded by submerged arc welding. .
[0053]
The welding conditions at this time are shown in Table 5 below, and the evaluation results of the appearance and penetration shape of the beads in the plate member having a plate thickness of 12 mm are shown in Table 6 below, and the appearance and melting of the beads in the plate member having a plate thickness of 25 mm are shown. Table 7 shows the evaluation results of the embedded shapes. In Tables 6 and 7 below, ○ (pass) indicates that the penetration depth increases by 10% or more of the plate thickness compared to the penetration depth of flat groove butt welding, and there is an underfill on the surface. It did not occur, and no molten metal melted off. Further, △ indicates that there was a rejected part depending on the welding position, × indicates that the penetration depth did not satisfy the acceptance criteria, XX indicates that the molten metal was burned out, − Indicates that the process for processing the concavo-convex surface is complicated and is not performed.
[0054]
[Table 5]

[0055]
[Table 6]

[0056]
[Table 7]

[0057]
As shown in Table 6 above, when the plate thickness is 12 mm, the depth of the recess is 0.5 mm or more, and when the pitch is 2 mm or more, the penetration depth increases, When the depth was 10 mm or more, the molten metal melted down.
[0058]
On the other hand, as shown in Table 7 above, when the plate thickness of the plate-like member was 25 mm, there was a pitch at which a good weld joint could be obtained up to a range where the depth of the recess was 15 mm. Moreover, when the pitch was 30 mm or more, the penetration depth varied greatly in the weld line direction.
[0059]
From these results, the depth of the recess for obtaining a good weld joint depends on the plate thickness, and when the depth of the recess on the uneven surface is up to 60% of the plate thickness of the member, the desired penetration depth Is obtained, and the molten metal can be prevented from being melted.
[0060]
In addition, by preparing a plate-like member with a modified uneven surface shape, assembling a joint by bringing this uneven surface into contact with another plate-like member, and welding this butt joint, the appearance and penetration of the bead The situation was evaluated. In addition, as the plate-like member for forming the uneven surface, two types of plate thicknesses of 12 mm and 25 mm are prepared. For the plate-like member having a plate thickness of 12 mm, MAG welding is performed. For the plate-like member having a plate thickness of 25 mm, Submerged arc welding was applied and welding was performed according to the welding conditions shown in Table 5 above.
[0061]
FIG. 6A is a plan view showing the shape of the plate-like member used in this example, and FIG. 6B is a front view thereof. As shown in FIG. 6, convex portions 21b extending from the front surface to the rear surface of the plate-like member 21 are formed at equal intervals on the end surface of the plate-like member 21, and a wide concave portion 21a is formed between the adjacent convex portions 21b. Has been.
[0062]
When the plate-like member 21 having an uneven surface having a shape as shown in FIG. 6 is used, when the depth D of the concave portion 21a is 0.5 to 3 mm, the width W of the convex portion is set to 5 mm or less. Even if the distance P between the convex parts to be carried out was about 50 mm, the evaluation result of the appearance and penetration state of the bead passed.
[0063]
FIG. 7 is a perspective view showing another shape of the plate-like member used in this embodiment. As shown in FIG. 7, the plate-like member 22 has a plurality of groove-like recesses 22a formed at equal intervals so as to extend from the upper surface of the plate-like member 22 to the back surface thereof. By forming, the convex part 22b is formed between the adjacent concave parts 22a. Therefore, on the end surface of the plate-like member 22, the concave portions 22a and the convex portions 22b are alternately arranged to have a waveform, but unlike the plate-like member 15 shown in FIG. It is formed to be inclined with respect to the direction orthogonal to the shape member 22.
[0064]
As a result of welding with various welding currents by changing the inclination angle of the inclined concave portion 22a in a range of 20 to 70 °, deep penetration can be obtained as compared with the case of welding a conventional flat groove portion. I was able to. Further, in this embodiment, even when the grooved concave portion 22a is formed in a direction orthogonal to the plate-like member (inclination angle 0 °), even if the welding current is increased, the molten metal is burned out. It became difficult.
[0065]
Therefore, the plate-like member 22 having such an uneven surface is effective for a joint that requires a penetration close to complete penetration. However, when the inclination angle of the groove-like recess 22a exceeds 60 °, it becomes difficult to process the uneven surface, and the effect of preventing the molten metal from being melted is not improved.
[0066]
【The invention's effect】
As described above in detail, according to the present invention, since the uneven surface is formed at the open tip of at least one member of the joint, the weld joint has high joint strength with deep penetration without forming an inclined groove. In addition, it is possible to prevent the molten metal from being burned out, whereby the processing and assembly for welding can be easily performed at a low cost. Moreover, since the convex part is in contact with the other member, welding shrinkage can be prevented even in the case of partial penetration welding, and the dimensional accuracy after welding can be increased. Furthermore, if this uneven surface is formed on the end surface of the plate-shaped member and a groove-shaped recess is formed so as to extend from the front surface to the back surface of the plate-shaped member, further processing and assembly become easier, and the depth of the recess on the uneven surface is reduced. By appropriately regulating the distance between the projections and the protrusions, it is possible to obtain an even better welded joint and improve the joint strength.
[Brief description of the drawings]
FIG. 1A is a perspective view showing a joint for explaining a joint welding method according to an embodiment of the present invention, FIG. 1B is a plan view thereof, and FIG. 1C is a front view thereof.
FIG. 2 is a front view showing the shape and size of a T-joint used in a penetration depth comparison test.
3A is a plan view showing the shape and size of a plate-like member used in a welding method according to an embodiment of the present invention, and FIG. 3B is a front view thereof.
FIG. 4 is a front view showing the shape and size of a T-joint having an inclined groove part used in a bending fatigue test.
FIG. 5A is a side view showing the shape and size of a test piece for a bending fatigue test, and FIG. 5B is a front view thereof.
6A is a plan view showing the shape of a plate-like member used in this example, and FIG. 6B is a front view thereof.
FIG. 7 is a perspective view showing another shape of the plate-like member used in this example.
FIG. 8 is a front view showing a groove shape of a conventional T joint.
FIG. 9 is a front view showing another groove shape of a conventional T joint.
[Explanation of symbols]
1, 2, 3, 4; steel plate 4a;

notches

5, 18; groove portion 10;

joints

11, 12, 13, 14, 15, 16, 17, 21, 22;

plate members

12a, 15a, 21a, 22a;

concave portions

12b, 15b, 21b, 22b; convex portion 19; fixing hole 20; weld metal 23; strain gauge

Claims

In the joint welding method for welding and joining two members, one member of the two members is a plate-like member, and an uneven surface is formed on an end surface of the plate-like member, and the uneven surface is attached to the other member. The groove is welded to the concave and convex surfaces by contacting with a member, and the concave and convex surfaces are formed by alternately forming concave portions and convex portions at a constant interval, and the concave portion has a space volume. When the plate thickness of the plate-like member is t (mm) when the volume of the convex portion is less than twice, the distance between adjacent convex portions is 2 to 20 mm, and the depth of the concave portion is (0.08 × t). to the (0.6 × t) mm, when the spatial volume of the recesses is more than twice the volume of the convex portion, the width of the convex portion 5mm or less, the depth of the recess 0.5 to 3 mm, the convex portion A joint welding method characterized in that the distance between them is 50 mm or less.

2. A plurality of groove-like recesses are formed in an end surface of the plate-like member in a direction orthogonal to the longitudinal direction of the plate-like member, and an uneven surface is formed by the recess. The method for welding joints described in 1.

A plurality of groove-like recesses inclined at 60 ° or less with respect to a direction orthogonal to the longitudinal direction of the plate-like member are formed on the end surface of the plate-like member, and an uneven surface is formed by the recess. The joint welding method according to claim 1.

4. The joint welding method according to claim 1, wherein the one member is formed with an inclined notch extending from the uneven surface to a surface adjacent thereto. 5.

5. The joint welding method according to claim 1, wherein the joint welding method according to claim 1, wherein the joint is used for a T joint in which an uneven surface of an end face of the plate-like member is brought into contact with a surface of the other member.