JP3671071B2

JP3671071B2 - Welding method and welding apparatus

Info

Publication number: JP3671071B2
Application number: JP20303495A
Authority: JP
Inventors: 馮井手
Original assignee: Denken Co Ltd
Current assignee: Denken Co Ltd
Priority date: 1995-08-09
Filing date: 1995-08-09
Publication date: 2005-07-13
Anticipated expiration: 2015-08-09
Also published as: JPH0952173A

Description

【０００１】
【発明の属する技術分野】
本発明は、鉄、ステンレス、アルミニウム、真鍮等の線材や棒材（被溶接材）を突き合わせ状態で溶接する方法及び溶接装置に関するもので、複数本の被溶接材を直線状に接合する場合の他、環状に曲成した１本の被溶接材の両端部を接合してリングを形成する場合にも利用される。
【０００２】
【従来の技術】
上記のような被溶接材を突き合わせ状態で溶接するのに、ガスシールドアーク溶接方法としてのティグ溶接が近年広く使用されている。この溶接方法は、不活性ガス（アルゴンガス、ヘリウムガス）の雰囲気中においてタングステン電極と被溶接材との間でアーク放電を行わせ、このアーク熱により被溶接材を溶融させる方法である。また、同様に被溶接材を突き合わせ状態で溶接する方法として、バット溶接（突き合わせ抵抗溶接）が知られている。このバット溶接は、両被溶接材を強く突き合わせ、これに大電流を通じ、接合部付近を抵抗発熱によって加熱し、適当な高温度に達したときに、両被溶接材を軸方向に加圧してアプセットする方法である。
【０００３】
【発明が解決しようとする課題】
従来のティグ溶接では、被溶接材の接合部の溶け込みが浅く、内部まで十分に融合し難いため、内部欠陥を発生する傾向があり、また接合部の放電側は溶け易いが、その反対側では溶け込みが悪く、溶接が不均一となって、溶接部の強度が低下する。また、特にティグ溶接では、溶接すべき両被溶接材を定位置に固定したまま放電を行うため、各被溶接材の突き合わせ端面が凹凸状を呈していたり、傾斜面状であると（実際に、被溶接材の端面は凹凸状を呈していることが多い）、両被溶接材の端面を突き合わせたときに両端面間に空隙ができ、しかして両被溶接材接合部の溶け込み量が少なくなって、接合部の周面部に図９の（Ａ）に示すような引け（凹陥部）Ｍを形成し、このため外観、見栄えも悪くなるだけでなく、溶接部の強度が著しく低下する。また、バット溶接にあっては、被溶接材の接合部が溶融状態で加圧されるため、図９の（Ｂ）に示すように被溶接材の径に対して可成り大きなバリＮが形成され、従って溶接後にこのバリＮを除去する作業に非常な手間と時間を要する。
【０００４】
本発明は、上記のような従来の溶接方法の問題点に鑑み、従来のティグ溶接に見られる引けや内部欠陥の発生を無くし、溶接強度の増大を図ることができると共に、従来のバット溶接によるバリの発生を極力無くするようにした溶接方法及び溶接装置を提供することを目的とする。
【０００５】
【課題を解決するための手段】
本発明の請求項１に係る溶接方法は、溶接すべき両被溶接材Ｗ，Ｗを同軸線上で突き合わせ、次いで両被溶接材Ｗ，Ｗの接合部の周囲を不活性ガス雰囲気にして、両被溶接材Ｗ，Ｗを軸方向に加圧しながら、両被溶接材Ｗ，Ｗ間に電流を通してその接合部を溶融する直前まで加熱した後、前記不活性ガス雰囲気中で両被溶接材Ｗ，Ｗの接合部にアークを放電して両被溶接材Ｗ，Ｗを接合するようにしたことを特徴とする。
【０００６】
請求項２は、アーク放電は、請求項１に記載の溶接方法において、被溶接材Ｗとの間でアークを発生するタングステン電極２７によって行わせることを特徴とする。
【０００７】
請求項３は、請求項１または２に記載の溶接方法において、両被溶接材Ｗ，Ｗの接合部の周囲を外気と遮断して不活性ガス雰囲気を形成するようにしたことを特徴とする。
【０００８】
請求項４に係る溶接装置は、溶接すべき両被溶接材Ｗ，Ｗの突き合わせ位置Ｐを挟んで被溶接材長手方向両側に固定台２及び可動台３を配設し、これら固定台２及び可動台３の各々に溶接電流供給用の電極８，９を介して被溶接材Ｗ，Ｗをクランプするクランプ機構１０，１１を設け、両被溶接材Ｗ，Ｗの接合部に向けて不活性ガスを供給して上記接合部の周囲を不活性ガス雰囲気にすると共に両被溶接材Ｗ，Ｗの接合部にアークを放電するためのトーチ２６を設け、前記可動台３を固定台２に近づく方向に押圧して両被溶接材Ｗ，Ｗを軸方向に加圧する加圧機構４と、この加圧機構４の押圧による可動台３の移動を制限するストッパー４２と、溶接用電源４６とを備えてなるもので、前記ストッパー４２の位置及び加圧時間を調整すると共に、被溶接材Ｗ，Ｗの接合部に通電される電流の強さと通電時間、及び前記接合部に放電されるアーク放電の強さと放電時間を、それぞれ所望に調整することによって、バリ及び引けの無い極めて良好な溶接を行うことができる。
【０００９】
請求項５は、請求項４に記載の溶接装置において、固定台２側及び可動台３側の各電極８，９は、それぞれ被溶接材Ｗが嵌合する被溶接材嵌合溝１２を形成して縦に二分割された上下一対の半割体１３ａ，１３ｂ、１８ａ，１８ｂからなるチップ電極１３，１８を含み、各チップ電極１３，１８の被溶接材嵌合溝１２は、その内周面の長手方向両端部のみ被溶接材Ｗと接触するよう中間部が深溝部１２ａを形成してなることを特徴とする。
【００１０】
請求項６は、請求項４または５に記載の溶接装置において、前記両被溶接材Ｗ，Ｗの接合部を囲繞して外気を遮断するフード２４を固定台２側の電極８と可動台３側の電極９との対向端部に取り付けてなることを特徴とする。
【００１１】
請求項７は、請求項６に記載の溶接装置において、フード２４は、各チップ電極１３，１８に外嵌可能な筒状に形成されると共に、縦に二分割された一対の半割体２４ａ，２４ｂからなり、両半割体２４ａ，２４ｂのそれぞれの一端部は、固定台２側チップ電極１３の半割体２４ａ，２４ｂの先端部にそれぞれ嵌合されて固定され、両半割体２４ａ，２４ｂのそれぞれの他端部は可動台３側チップ電極１８の半割体２４ａ，２４ｂの先端部に軸方向スライド可能に嵌合されてなることを特徴とする。
【００１２】
【発明の実施の形態】
実施例について図面を参照して説明すると、図１は、本発明に係る溶接方法を実施するための溶接装置の主要部を正面図で示し、図２は図１のＸ−Ｘ線断面図、図３は図１のＹ−Ｙ線断面図を示したものである。これらの図において、１は左右方向に長い装置基板で、図１から明らかなように、この装置基板１の右側には、溶接すべき両被溶接材の突き合わせ位置Ｐを挟んでその左右方向（被溶接材長手方向）両側に固定台２（右側）及び可動台３（左側）が配設され、装置基板１の左側には可動台３を固定台２に近づく方向（右方）に加圧する加圧機構４が設けられている。
【００１３】
固定台２及び可動台３は、装置基板１に設けられた左右方向に延びる上下のガイドレール５，６に係合支持され、固定台２は、両ガイドレール５，６の所定位置に常時固定されているが、必要に応じて移動調整できるようになっており、可動台３は、両ガイドレール５，６に沿ってスライド可能となっている。下部側のガイドレール６は、その中央部分、即ち溶接すべき両被溶接材の突き合わせ位置Ｐを含む所要長さ部分が切除され、そして装置基板１の前記ガイドレール切除部分に対応する部分が下向きＵ字状に切欠されており、そのＵ字状切欠部分を図１に７で示す。
【００１４】
また、固定台２及び可動台３には、それぞれ溶接電流供給用の電極８，９を介して各被溶接材Ｗをクランプするクランプ機構１０，１１が設けられている。固定台２側の電極８は、図４及び図５に示すように、被溶接材Ｗが嵌合する断面半円形の被溶接材嵌合溝１２，１２を形成して縦に二分割された上下一対の半割体１３ａ，１３ｂからなるチップ電極１３と、チップ電極１３の各半割体１３ａ，１３ｂのそれぞれ外側に固着された上下の外部電極片１４，１５とから構成され、下側の外部電極片１５は、図１及び図２に示すように固定台２に固定されている。固定台２側のクランプ機構１０は、上下一対の半割体１３ａ，１３ｂからなるチップ電極１３を介して被溶接材Ｗをクランプするもので、チップ電極１３の上下両半割体１３ａ，１３ｂと、固定台２にブラケット１６により取付けられて上側の外部電極片１４を昇降駆動し、それによって上部の半割体１３ａを下部の半割体に対し開閉するクランプシリンダ１７（エアシリンダ）とからなる。
【００１５】
可動台３側の電極９は、図６及び図５に示すように、被溶接材Ｗが嵌合する断面半円形の被溶接材嵌合溝１２，１２を形成して縦に二分割された上下一対の半割体１８ａ，１８ｂからなるチップ電極１８と、チップ電極１８の各半割体１８ａ，１８ｂのそれぞれ外側に固着された上下の外部電極片１９，２０とから構成され、下側の外部電極片２０は、図１に示すように可動台３に固定されている。また、可動台３側のクランプ機構１１は、上下一対の半割体１８ａ，１８ｂからなるチップ電極１８を介して被溶接材Ｗをクランプするもので、このチップ電極１８の上下両半割体１８ａ，１８ｂと、可動台３にブラケット２１により取付けられて上側の外部電極片１９を昇降駆動し、それによって上部の半割体１８ａを下部の半割体１８ｂに対し開閉するクランプシリンダ２２（エアシリンダ）と、からなる。
【００１６】
図１には、固定台２側及び可動台３側の両クランプ機構１０，１１がクランプ位置にある状態を実線で示し、また両クランプ機構１０，１１がクランプ解除された状態を仮想線で示している。
【００１７】
また、図５に示すように、固定台２側及び可動台３側の各チップ電極１３を構成する半割体１３ａ，１３ｂ、１８ａ，１８ｂのそれぞれの被溶接材嵌合溝１２は、その内周面の長手方向両端部のみが被溶接材Ｗと接触するよう中間部が深溝に形成されており、その深溝部を１２ａで示す。このような深溝部１２ａを深溝部１２ａを形成することによって、各チップ電極１３，１８からの電流が、各チップ電極１３，１８の先端部から各被溶接材Ｗに流れ、それにより電流を各被溶接材Ｗの接合端部に集中して効率良く流すことができると共に、各チップ電極１３，１８の損傷を防止することができる。また、各外部電極片１４，１５、１９，２０には、内部に冷却水を通して当該外部電極片を冷却するための冷却水流路２３がそれぞれ設けてある。
【００１８】
固定台２側のチップ電極１３及び可動台３側のチップ電極１８の互いに対向する端部間には、溶接すべき両被溶接材Ｗ，Ｗの接合部を囲繞して外気を遮断する筒状のフード２４が介装されている。このフード２４は、電気絶縁性を有し且つ耐熱性に優れた材料によって各チップ電極１３，１８に外嵌可能な筒状に形成されると共に、各チップ電極１３，１８と同様に縦に二分割された一対の半割体２４ａ，２４ａからなるもので、図４から明らかなのように、両半割体２４ａ，２４ａのそれぞれの一端部が、固定台２側チップ電極１３の半割体１３ａ１３ｂの先端部にそれぞれ嵌合されてビス２５で固定され、両半割体２４ａ，２４ａのそれぞれの他端部は、図１に示すように可動台３側チップ電極１８の半割体半割体１８ａ，１８ｂの先端部に軸方向摺動可能に嵌合される。
【００１９】
また、図２において２６は、前記フード２４内にアルゴンガスやヘリウムガス等の不活性ガスを供給する不活性ガス供給部（図示省略）、及び両被溶接材Ｗ、Ｗの接合部にアークを放電するためのタングステン電極２７を備えた放電用のトーチで、被溶接材Ｗと直交するように配設され、トーチ２６先端部がフード２４の開口部２８（図２及び図４参照）に突入嵌合している。このトーチ２６は、従来のティグ溶接用トーチを使用することができる。このトーチ２６は、図２に示すように、装置基板１に設けてあるＵ字状切欠部分７より挿入されて、所定の姿勢でこの装置基板１に固定される。
【００２０】
前記加圧機構４を図１及び図３を参照して説明すると、この加圧機構４は、ネジ軸からなる加圧駆動軸２９を、装置基板１に固定された左右一対の縦板３０，３１にそれらの貫通孔３０ａ，３１ａを介して水平に支持すると共に、加圧駆動軸２９の中間所要部に螺嵌されたバネ圧調整部材３２と、前記左側の縦板３０との間に加圧用コイルバネ３３を介装して、加圧駆動軸２９の先端面が可動台３に取付けた鋼球３４を介して当該可動台３を押圧付勢するようにし、前記バネ圧調整部材３２と前記右側の縦板３１との間には、矩形体状のカムローラー取付台３５を螺嵌すると共に、当該取付台３５下面を装置基板１に固定された水平ガイド板３６の上面に摺動可能に載置し、この取付台３５の両側部にカムローラー３７，３７を軸支し、これらカムローラー３７，３７と前記縦板３１との間には、装置基板１上に設置されたエアシリンダ３８により昇降駆動される加圧用のカム板３９を、そのカム面３９ａが前記カムローラー３７，３７と係合し且つ反対側の側面３９ｂが前記縦板３１と摺接するように介装してなるものである。エアシリンダ３８はブラケット４０を介して装置基板１に取付けられる。尚、４１は、カムローラー取付台３５を加圧駆動軸２９の定位置に固定するロックナットである。
【００２１】
上記の構成よりなる加圧機構４の作動において、通常時は、可動台３に押圧力がかからないようにエアシリンダ３８によってカム板３９が図１の実線図示のような位置まで降下している。しかして、溶接に際し被溶接材Ｗを軸方向に加圧する時には、エアシリンダ３８を図１の実線図示位置から所定ストローク収縮作動させることにより、カム板３９が例えば同図の仮想線図示位置まで上動すると、このカム板３９の上動に伴い、カム面３９ａに圧接しているカムローラー３７，３７が水平変移し、同時にカムローラー取付台３５が水平ガイド板３６上を摺動して、加圧駆動軸２９が前記鋼球３４を介して可動台３を、固定台２に近づく方向（右方向）に所要量だけ押圧して移動させ、これによりこの可動台３側のクランプ機構１１でクランプされている被溶接材Ｗと、固定台２側のクランプ機構１０でクランプされている被溶接材Ｗとが互いに軸方向に加圧される。
【００２２】
図１及び図２において４２は、加圧機構４の押圧作動による可動台３の移動を制限するストッパーで、装置基板１側に設けてある。このストッパー４２は、図１及び図２に示すように、装置基板１に固定したブラケットｂにストッパー取付台ｃを水平方向移動調整可能に取り付け、このストッパー取付台ｃにボルトからなるストッパー片ａを水平方向移動調整可能に螺装してなるもので、このストッパー片ａの先端に可動台３の端面を当接させて可動台３の移動量（即ち、加圧量）を制限するようにしている。この場合、ストッパー取付台ｃは、これに長穴ｄを設けてこの長穴ｄからブラケットｂにボルトｅを螺入することによってブラケットｂに水平方向移動調整可能に取り付けることができる。
【００２３】
従って、ストッパー４２の位置調整は、ストッパー取付台ｃによって比較的大幅に行うことできると共に、ストッパー取付台ｃに螺合されたストッパー片ａを適宜に回転させることによって微調整することができる。尚、この実施例の加圧機構４では、ストッパー４２の位置調整を手動で行うようにしているが、例えばボールねじをモーターで回転駆動させる方式を採用するなどして自動的に行わせることができるものである。また、この加圧機構４において、加圧力（押圧力）の調整は、加圧駆動軸２９に螺嵌されたバネ圧調整部材３２を適宜回転させてコイルバネ３３のバネ圧を調整することにより行う。
【００２４】
また、図４〜図６に示すチップ電極１３，１８は、溶接すべき両被溶接材Ｗ，Ｗを直線状に接合する場合の構造を示したものであるが、例えば弯曲状に形成された両被溶接材Ｗ′，Ｗ′を溶接する場合、あるいは弯曲状に形成された１本の被溶接材Ｗ′の両端部を溶接する場合には、図１０の（Ａ）及び（Ｂ）に示すように、各チップ電極１３，１８の各半割体１３ａ，１３ｂ、１８ａ，１８ｂには、弯曲状被溶接材Ｗ′の形状に対応する平面視弯曲状の断面半円形嵌合溝４２を形成すればよい。
【００２５】
尚、この溶接装置では、両被溶接材Ｗ，Ｗの接合部の周囲を外気と遮断するためにフード２４を固定台２側の電極８と可動台３側の電極９との対向端部に取り付けているが、このようなフード２４を使用する代わりに、両被溶接材Ｗ，Ｗの突き合わせ位置Ｐを挟んでトーチ２６の反対側に耐熱性及び電気絶縁性の反射板を設けたり、あるいは複数本、例えば３〜４本のトーチ２６を両被溶接材Ｗ，Ｗの突き合わせ位置Ｐの周りに放射状に配設するようにしてもよい。この実施例のようなフード２４を使用すれば、両被溶接材Ｗ，Ｗの接合部の周囲を確実に外気と遮断することができ、また取付けが簡単且つ容易となる。
【００２６】
図１１は、上述した溶接装置全体の概略構成とその電気回路を示したもので、この図において、４３は加熱トランス、ＭＳは加熱用のスイッチ、４４はティグ溶接用の高周波発生装置、４５は制御装置、４６は溶接用電源である。図１３は、制御装置４５のシーケンス回路を示したものである。
【００２７】
次に、上記溶接装置の使用による直線状被溶接材Ｗの溶接方法について、図７の溶接工程図、図１３のシーケンス回路及び図１２のシーケンスタイムチャートを参照して説明する。
【００２８】
先ず、固定台２側及び可動台３側の両クランプ機構１０，１１が開放（クランプ解除）された状態で、図７の（Ａ）に示すように、固定台２側及び可動台３側のチップ電極１３，１８内に両方の被溶接材Ｗ，Ｗを配置して、それらの対向端面を突き合わせる。次に、図１３に示すように、押しボタンＰＢ１（例えばフットスイッチ）を押すと、リレーコイルＣＲ１が励磁されてその接点が閉じ、クランプ機構１０のクランプシリンダ１７がクランプ作動し、タイマーＴ１により一定時間経過後にクランプシリンダ１７をロックし、固定台２側のチップ電極１３を介して右側の被溶接材Ｗがクランプされる。そして、押しボタンＰＢ２を押すと、リレーコイルＣＲ２が励磁されてその接点が閉じ、可動台３側（図１の左側）のクランプ機構１１のクランプシリンダ２２がクランプ作動し、タイマーＴ２により一定時間経過後にクランプシリンダ２２をロックし、可動台３側のチップ電極１８を介して左側の被溶接材Ｗがクランプされる。両被溶接材Ｗ，Ｗのクランプ状態を図７の（Ｂ）に示す。
【００２９】
タイマーＴ２によりリレーコイルＣＲ３が励磁されてその接点が閉じ、そしてタイマーＴ３の作動で一定時間経過後に不活性ガスが放出されて、トーチ２６を通じフード２４内に供給され、フード２４内の空気が追い出される。引続き、タイマーＴ３によりリレーコイルＣＲ４が励磁されてその接点が閉じ、タイマーＴ４の作動で一定時間経過後に加圧機構４が作動して、可動台３、クランプ機構１１を介して両被溶接材Ｗ，Ｗが対向方向に加圧され、その加圧状態を図７の（Ｃ）に示す。
【００３０】
次いで、一定時間後にタイマーＴ４が作動して、リレーコイルＣＲ５とタイマーＴ５とタイマーＴ６とが励磁され、リレーコイルＣＲ５の通電により加熱用のスイッチＭＳが閉じ、加熱が開始される。即ち、外部電極片１４，１５、１９，２０及びチップ電極１３，１８を介して被溶接材Ｗ，Ｗの接合部に電流（例えば２０Ａ／mm²）が通され、その抵抗発熱によって接合部の加熱が開始される。そして、一定時間後にタイマーＴ５の作動によりリレーコイルＣＲ６が励磁されてその接点が閉じ、これにより加熱が終了する。この加熱が終了した時点（あるいは終了する直前でもよい）で、タイマーＴ６によってリレーコイルＣＲ７とタイマーＴ７が励磁され、またリレーコイルＣＲ１０が励磁されて放電が開始される。そして、一定時間後にタイマーＴ７によってリレーコイルＣＲ８が消磁され、リレーコイルＣＲ１０の接点が開き、放電が停止される。これと同時に、タイマーＴ７によりタイマーＴ８が励磁され、一定時間後にリレーコイルＣＲ９が励磁されてその接点が開き、溶接が終了し、リレー回路は元の状態に復帰する。
【００３１】
上述した一連の溶接工程における各動作時間の具体例は、図１２のシーケンスタイムチャートに示す通りである。この図において、残熱時間とあるのは、溶接終了後の保持時間（例えば３秒）である。
【００３２】
以上説明したように、この溶接方法は、両被溶接材Ｗ，Ｗを同軸線上で軽く突き合わせた後、両被溶接材Ｗ，Ｗの接合部の周囲をフード２４で覆って不活性ガス雰囲気にした状態で、両被溶接材Ｗ，Ｗを軸方向に加圧しながら、両被溶接材Ｗ，Ｗ間に電流を通してその接合部を溶融する直前まで加熱し、しかる後、不活性ガス雰囲気中で両被溶接材Ｗ，Ｗの接合部にアークを放電して両被溶接材を接合する方法であるから、従来のティグ溶接のように溶接部に引け（凹陥部）ができない。即ち、本発明方法によれば、各被溶接材Ｗの突き合わせ端面が凹凸状や傾斜面状を呈していて突き合わせ端面間に空隙ができている場合であっても、両被溶接材Ｗ，Ｗの接合部が溶融する直前まで加熱しつつ両被溶接材Ｗ，Ｗを軸方向に一定量加圧し、しかも加熱後に接合部にアークを放電させることによって、突き合わせ端面の凹凸状部や傾斜状部が当該突き合わせ端面間の空隙を埋めるように自然に押し潰された状態となり、このためティグ溶接に見られるような引けができず、図８に示すように被溶接材Ｗ，Ｗの接合端部が被溶接材Ｗの径と殆ど同径となる。この場合に両被溶接材Ｗ，Ｗを軸方向に加圧する加圧量は、両被溶接材Ｗの突き合わせ端面の形態に応じて前記ストッパー４２の位置を調整することによって適宜に設定することができる。即ち、両被溶接材Ｗ，Ｗの突き合わせ端面間の空隙部が多ければば、それだけ加圧量、即ち可動台３の移動量を大きくすればよく、また上記空隙部が少ないときは、その可動台３の移動量を小さくすればよい。これによって、被溶接材Ｗの凹凸や傾斜状態に応じて溶け込み量を所望に調整できて、引けやバリのない極めて良好な溶接を行うことができる。
【００３３】
また、この溶接方法によれば、従来のティグ溶接で問題とされる溶け込み不良、内部欠陥の発生がなくなる。即ち、両被溶接材Ｗ，Ｗの接合部の周囲を不活性ガス雰囲気にした状態で、両被溶接材Ｗ，Ｗを軸方向に加圧しながら、抵抗発熱により非溶融状態まで加熱した後、この非溶融状態の接合部にアークを放電し、接合部の溶け込みが良く、内部まで完全に融合することができ、またその溶け込みは、トーチによる放電側のみに偏らず接合部の全周に均一になされることになり、従って溶接部全体が均質となり、溶接部の強度を増大させることができ、しかも上記加熱及びアーク放電をともに不活性ガス雰囲気中で行うから、溶接部の酸化が防止され、変色や変質もなく良好な溶接が得られることになる。
【００３４】
また、この溶接方法は、上記のように両被溶接材Ｗ，Ｗを軸方向に定量加圧しながら、両被溶接材Ｗ，Ｗ間に電流を通してその接合部を溶融する直前まで加熱した後、アークを放電して溶接するため、従来のバット溶接に見られるようなバリが発生せず、図８に示すように、溶接部には若干の隆起部は見られるものの、被溶接材Ｗの径と殆ど変わりなく、良好な溶接部が形成される。
【００３５】
また、上述した溶接装置には、図示は省略するが、両被溶接材Ｗ，Ｗの接合部が溶融する直前まで通電するために電流の強さと通電時間を調整するための装置、及びアーク放電の強さ及び放電時間を調整するための装置を具備している。従って、この溶接装置によれば、前記ストッパー４２の位置を調整すると共に、被溶接材Ｗ，Ｗの接合部に通電される電流の強さと通電時間、及び前記接合部に放電されるアーク放電の強さと放電時間を、それぞれ所望に調整することによって、引けやバリの発生の無い極めて良好な溶接を行うことができる。
【００３６】
【発明の効果】
本発明の請求項１に係る溶接方法によれば、両被溶接材の接合部が溶融する直前まで加熱しつつ両被溶接材を軸方向に一定量加圧し、しかも加熱後に接合部にアークを放電させるようにするため、各被溶接材の突き合わせ端面が凹凸状や傾斜面状を呈していて突き合わせ端面間に空隙ができている場合であっても、突き合わせ端面の凹凸状部や傾斜状部が当該突き合わせ端面間の空隙を埋めるように自然に溶け込んで接合部が均一に融合し、このためティグ溶接に見られるような引けができず、被溶接材の接合端部が被溶接材の径と殆ど同径の良好な溶接を行うことができる。
【００３７】
また、従来のティグ溶接で問題とされる溶け込み不良、内部欠陥の発生がなくなる。即ち、両被溶接材の接合部を軸方向に加圧しながら、アーク放電に先立って予め抵抗発熱により非溶融状態まで加熱し、しかる後この非溶融状態の接合部にアークを放電するから、接合部の溶け込みが良く、内部まで完全に融合することができ、またその溶け込みは、放電側のみに偏らず接合部の全周に均一になされる、従って溶接部全体が均質となり、溶接部の強度を増大させることができる。しかも、上記加熱及びアーク放電をともに不活性ガス雰囲気中で行うから、加熱及びアーク放電中での溶接部の酸化が防止され、変色や変質のない良好が溶接が得られる。
【００３８】
更に、両被溶接材を軸方向に加圧しながら、両被溶接材の接合部を溶融する直前まで加熱した後、アークを放電して溶接するため、従来のバット溶接に見られるようなバリが発生せず、被溶接材Ｗの径と殆ど変わりなく、良好な溶接部が形成され、従って溶接部の強度が増大する上に、外観、見栄えも良くなる。
【００３９】
請求項２によれば、アーク放電を、被溶接材との間でアークを発生するタングステン電極によって行わせることにより、高温のアーク熱によっても、電極の消耗が少なく、アークの安定性が良好となる。
【００４０】
請求項３によれば、両被溶接材の接合部の周囲を外気と遮断して不活性ガス雰囲気を形成することによって、アーク放電が極めて効果的に行える。
【００４１】
請求項４に係る溶接装置によれば、請求項１に係る溶接方法を有効に実施することができ、それによって請求項１で述べたような効果を奏することができる。特に、この溶接装置では、加圧機構の押圧による可動台の移動を制限するストッパーを備えているから、このストッパーの位置を両被溶接材の突き合わせ端面の形態や被溶接材の径の大きさ等に応じて調整することにより、両被溶接材を軸方向に加圧する加圧量を調整し、それによって溶け込み量を所望に調整でき、しかしてこのストッパーの位置調整と共に、被溶接材接合部に通電される電流の強さと通電時間、及び前記接合部に放電されるアーク放電の強さと放電時間を、それぞれ所望に調整することによって、引け及びバリの無いきわめて良好な溶接を行うことができる。
【００４２】
請求項５によれば、チップ電極からの電流が、各チップ電極の先端部から各被溶接材に流れ、それにより電流を各被溶接材の接合端部に集中して効率良く流すことができると共に、各チップ電極の損傷を防止することができる。
【００４３】
請求項６によれば、両被溶接材の接合部を囲繞して外気を遮断するフードを固定台側の電極と可動台側の電極との対向端部に取り付けることによって、両被溶接材の接合部の周囲を確実に外気と遮断することができる。
【００４４】
請求項７によれば、チップ電極へのフードの取付けが簡単容易であると共に、可動台の加圧移動時に可動台側のチップ電極が移動しても何ら支障を来すことがない。
【図面の簡単な説明】
【図１】本発明に係る溶接装置を示す全体正面図である。
【図２】図１のＸ−Ｘ線断面図である。
【図３】図１のＹ−Ｙ線断面図である。
【図４】（Ａ）は固定台側の電極を示す正面図、（Ｂ）は（Ａ）のＺ−Ｚ線断面図である。
【図５】チップ電極を示す分解斜視図である。
【図６】（Ａ）は可動台側の電極を示す正面図、（Ｂ）は（Ａ）の右側面図である。
【図７】（Ａ）〜（Ｄ）は溶接工程を示す説明図である。
【図８】本発明方法により溶接された被溶接材を示す正面図である。
【図９】（Ａ）は従来のティグ溶接により溶接された被溶接材の正面図、（Ｂ）は従来のバット溶接により溶接された被溶接材の正面図である。
【図１０】（Ａ）は弯曲状被溶接材をチップ電極にセットした状態を示す斜視図、（Ｂ）はチップ電極の片方の半割体を取り外した状態での平面図である。
【図１１】本発明に係る溶接装置の全体概略構成図である。
【図１２】同上の溶接装置の使用による溶接におけるシーケンスタイムチャートである。
【図１３】同上の溶接装置におけるシーケンス回路図である。
【符号の説明】
Ｗ被溶接材
１装置基板
２固定台
３可動台
４加圧機構
５ガイドレール
６ガイドレール
８固定台側の電極
９可動台側の電極
１０固定台側のクランプ機構
１１可動台側のクランプ機構
１２被溶接材嵌合溝
１２ａ深溝部
１３固定台側のチップ電極
１８可動台側のチップ電極
２４フード
２４ａ半割体
２６トーチ
２７タングステン電極
４２ストッパー
４５制御装置
４６溶接電源[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and a welding apparatus for welding wires, rods (welded materials) such as iron, stainless steel, aluminum, and brass in a butted state, and in the case of joining a plurality of welded materials linearly. In addition, it is also used when a ring is formed by joining both end portions of one welded material that is bent in an annular shape.
[0002]
[Prior art]
TIG welding as a gas shielded arc welding method has been widely used in recent years for welding the above-mentioned welded materials in a butt state. This welding method is a method in which arc discharge is performed between a tungsten electrode and a material to be welded in an atmosphere of an inert gas (argon gas or helium gas), and the material to be welded is melted by the arc heat. Similarly, butt welding (butt resistance welding) is known as a method of welding the workpieces in a butt state. In this butt welding, both welded materials are strongly butted together, a large current is passed through them, the vicinity of the joint is heated by resistance heat generation, and when the appropriate high temperature is reached, both welded materials are pressed in the axial direction. How to upset.
[0003]
[Problems to be solved by the invention]
In conventional TIG welding, the welded material has a shallow penetration at the joint, and it is difficult to fuse it to the inside.Therefore, internal defects tend to occur, and the discharge side of the joint tends to melt. The penetration is poor, the welding becomes uneven, and the strength of the welded portion decreases. In particular, in TIG welding, since discharge is performed with both welded materials to be welded fixed at fixed positions, the butt end surfaces of each welded material are uneven or inclined (actually The end face of the welded material often has an uneven shape), and when the end faces of the two welded materials are brought into contact with each other, a gap is formed between the two end faces, and the amount of penetration of the welded material joint is small. As a result, a shrinkage (concave portion) M as shown in FIG. 9A is formed on the peripheral surface portion of the joint portion, which not only deteriorates the appearance and appearance but also significantly reduces the strength of the welded portion. Further, in butt welding, since the joint portion of the material to be welded is pressurized in a molten state, a considerably large burr N is formed with respect to the diameter of the material to be welded as shown in FIG. Therefore, it takes much time and labor to remove the burr N after welding.
[0004]
In view of the problems of the conventional welding method as described above, the present invention eliminates the occurrence of shrinkage and internal defects as seen in conventional TIG welding, can increase the welding strength, and is based on conventional butt welding. It is an object of the present invention to provide a welding method and a welding apparatus in which the generation of burrs is minimized.
[0005]
[Means for Solving the Problems]
In the welding method according to claim 1 of the present invention, both the workpieces W, W to be welded are butted on the coaxial line, and then the periphery of the joint portion of the workpieces W, W is made an inert gas atmosphere. While heating the workpieces W, W in the axial direction, heating the joints immediately before melting the joints by passing an electric current between the workpieces W, W, then both the workpieces W, W in the inert gas atmosphere. An arc is discharged to the joint portion of W to join the workpieces W and W together.
[0006]
According to a second aspect of the present invention, in the welding method according to the first aspect, the arc discharge is performed by a tungsten electrode 27 that generates an arc with the workpiece W.
[0007]
According to a third aspect of the present invention, in the welding method according to the first or second aspect of the present invention, an inert gas atmosphere is formed by blocking the periphery of the joint portion of the workpieces W and W from the outside air. .
[0008]
In the welding apparatus according to claim 4, the fixed base 2 and the movable base 3 are disposed on both sides in the longitudinal direction of the welded material across the butting position P of the welded materials W and W to be welded. Clamp mechanisms 10 and 11 for clamping the workpieces W and W via the electrodes 8 and 9 for supplying welding current are provided on each of the movable bases 3 and are inactive toward the joint portions of the workpieces W and W. A gas is supplied to bring the periphery of the joint to an inert gas atmosphere, and a torch 26 for discharging an arc is provided at the joint between the welded materials W and W so that the movable base 3 approaches the fixed base 2. A pressure mechanism 4 that presses the workpieces W and W in the axial direction and presses the workpieces W in the axial direction, a stopper 42 that restricts the movement of the movable table 3 by the pressure of the pressure mechanism 4, and a welding power source 46. The position of the stopper 42 and the pressurization time are adjusted. By adjusting the strength of the current to be welded to the welded parts W and W and the duration of the current, and the strength and discharge time of the arc discharge to be discharged to the joint, as desired, There can be very good welding.
[0009]
According to a fifth aspect of the present invention, in the welding apparatus according to the fourth aspect, each of the electrodes 8 and 9 on the fixed base 2 side and the movable base 3 side forms a welded material fitting groove 12 into which the welded material W is fitted. And the chip electrodes 13 and 18 comprising a pair of upper and lower halves 13a, 13b, 18a and 18b which are vertically divided into two, and the welded material fitting groove 12 of each of the chip electrodes 13 and 18 has an inner periphery thereof. The intermediate portion is formed with a deep groove portion 12a so that only the both ends in the longitudinal direction of the surface are in contact with the workpiece W.
[0010]
A sixth aspect of the present invention is the welding apparatus according to the fourth or fifth aspect, wherein the hood 24 surrounding the joint portion of the workpieces W and W to block outside air is provided with the electrode 8 on the fixed base 2 side and the movable base 3. It is characterized by being attached to the end facing the side electrode 9.
[0011]
A seventh aspect of the present invention is the welding apparatus according to the sixth aspect, wherein the hood 24 is formed in a cylindrical shape that can be fitted onto the tip electrodes 13 and 18 and is vertically divided into a pair of halves 24a. 24b, and one end of each of the halves 24a, 24b is fitted and fixed to the tip of each of the halves 24a, 24b of the fixed base 2 side chip electrode 13, and both halves 24a , 24b are respectively fitted to the distal ends of the halves 24a, 24b of the movable stage 3-side chip electrode 18 so as to be axially slidable.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment will be described with reference to the drawings. FIG. 1 is a front view showing a main part of a welding apparatus for carrying out a welding method according to the present invention, and FIG. 2 is a sectional view taken along line XX in FIG. FIG. 3 is a sectional view taken along line YY of FIG. In these drawings, reference numeral 1 denotes a device substrate that is long in the left-right direction. As is clear from FIG. 1, the right-hand side of the device substrate 1 is positioned in the left-right direction with the butting position P of both workpieces to be welded in between. A fixed base 2 (right side) and a movable base 3 (left side) are arranged on both sides of the workpiece (longitudinal direction), and the movable base 3 is pressurized on the left side of the apparatus substrate 1 in a direction approaching the fixed base 2 (right side). A pressure mechanism 4 is provided.
[0013]
The fixed base 2 and the movable base 3 are engaged and supported by upper and lower guide rails 5 and 6 provided in the apparatus substrate 1 and extending in the left-right direction, and the fixed base 2 is always fixed at a predetermined position of both the guide rails 5 and 6. However, the movement can be adjusted as necessary, and the movable base 3 can slide along both guide rails 5 and 6. The lower portion of the guide rail 6 is cut at a central portion thereof, that is, a required length portion including the butting position P of both workpieces to be welded, and a portion corresponding to the guide rail cut portion of the apparatus substrate 1 is directed downward. The U-shaped notch is indicated by 7 in FIG.
[0014]
The fixed base 2 and the movable base 3 are provided with clamp mechanisms 10 and 11 for clamping the workpieces W via electrodes 8 and 9 for supplying welding current, respectively. As shown in FIGS. 4 and 5, the electrode 8 on the fixing base 2 side is divided into two vertically by forming welded material fitting grooves 12, 12 having a semicircular cross section into which the welded material W is fitted. The chip electrode 13 includes a pair of upper and lower halves 13a and 13b, and upper and lower external electrode pieces 14 and 15 fixed to the outer sides of the halves 13a and 13b of the chip electrode 13, respectively. The external electrode piece 15 is fixed to the fixed base 2 as shown in FIGS. The clamp mechanism 10 on the fixed base 2 side clamps the workpiece W via the tip electrode 13 composed of a pair of upper and lower halves 13a and 13b. The upper and lower halves 13a and 13b of the tip electrode 13 And a clamp cylinder 17 (air cylinder) which is attached to the fixed base 2 by a bracket 16 to drive the upper external electrode piece 14 up and down, thereby opening and closing the upper half 13a with respect to the lower half. .
[0015]
As shown in FIGS. 6 and 5, the electrode 9 on the movable table 3 side is divided into two vertically by forming welded material fitting grooves 12 and 12 having a semicircular cross section into which the welded material W is fitted. The chip electrode 18 includes a pair of upper and lower halves 18a and 18b, and upper and lower external electrode pieces 19 and 20 fixed to the outer sides of the halves 18a and 18b of the chip electrode 18, respectively. The external electrode piece 20 is fixed to the movable table 3 as shown in FIG. The clamp mechanism 11 on the movable table 3 side clamps the workpiece W via the tip electrode 18 composed of a pair of upper and lower halves 18a and 18b. The upper and lower halves 18a of the tip electrode 18 are clamped. , 18b, and a clamp cylinder 22 (air cylinder) that is attached to the movable base 3 by a bracket 21 to drive the upper external electrode piece 19 up and down, thereby opening and closing the upper half 18a relative to the lower half 18b. ).
[0016]
In FIG. 1, the state in which both the clamp mechanisms 10 and 11 on the fixed base 2 side and the movable base 3 side are in the clamp position is indicated by a solid line, and the state in which both the clamp mechanisms 10 and 11 are released from the clamp is indicated by a virtual line. ing.
[0017]
Further, as shown in FIG. 5, the welded material fitting grooves 12 of the halves 13a, 13b, 18a, and 18b constituting the chip electrodes 13 on the fixed base 2 side and the movable base 3 side are respectively formed therein. The intermediate part is formed in the deep groove so that only the both ends in the longitudinal direction of the peripheral surface are in contact with the workpiece W, and the deep groove part is indicated by 12a. By forming the deep groove portion 12a in such a deep groove portion 12a, currents from the chip electrodes 13 and 18 flow from the tip portions of the chip electrodes 13 and 18 to the welded materials W, whereby currents are supplied to the respective While being able to concentrate on the joining edge part of the to-be-welded material W and to flow efficiently, damage to each chip electrode 13 and 18 can be prevented. Each of the external electrode pieces 14, 15, 19, and 20 is provided with a cooling water passage 23 for cooling the external electrode piece through the cooling water.
[0018]
Between the mutually opposing ends of the tip electrode 13 on the fixed base 2 side and the tip electrode 18 on the movable base 3 side, a cylindrical shape that surrounds the joint portion of both the workpieces W and W to be welded and blocks outside air. The hood 24 is interposed. The hood 24 is formed in a cylindrical shape that can be externally fitted to the chip electrodes 13 and 18 with a material having electrical insulation properties and excellent heat resistance, and in the same manner as the chip electrodes 13 and 18, As is apparent from FIG. 4, one end of each of the halves 24a, 24a is formed by a pair of divided halves 24a, 24a. 1 and are fixed by screws 25, and the other ends of both halves 24a, 24a are halves of the movable base 3 side chip electrode 18, as shown in FIG. The tip ends of 18a and 18b are fitted so as to be slidable in the axial direction.
[0019]
In FIG. 2, reference numeral 26 denotes an inert gas supply unit (not shown) for supplying an inert gas such as argon gas or helium gas into the hood 24, and an arc at the joint between the workpieces W and W. A discharge torch provided with a tungsten electrode 27 for discharge, which is disposed so as to be orthogonal to the workpiece W, and the tip of the torch 26 enters the opening 28 (see FIGS. 2 and 4) of the hood 24. It is mated. As this torch 26, a conventional TIG welding torch can be used. As shown in FIG. 2, the torch 26 is inserted from a U-shaped cutout portion 7 provided on the apparatus substrate 1 and is fixed to the apparatus substrate 1 in a predetermined posture.
[0020]
The pressurizing mechanism 4 will be described with reference to FIGS. 1 and 3. The pressurizing mechanism 4 includes a pair of left and right vertical plates 30 fixed to the apparatus substrate 1 with a pressurizing drive shaft 29 formed of a screw shaft. 31 is supported horizontally through the through holes 30a, 31a, and between the spring pressure adjusting member 32 screwed into the intermediate required portion of the pressure drive shaft 29 and the left vertical plate 30. A pressure coil spring 33 is interposed so that the tip surface of the pressure drive shaft 29 presses and urges the movable table 3 through a steel ball 34 attached to the movable table 3. A rectangular cam roller mount 35 is screwed between the right vertical plate 31 and the lower surface of the mount 35 is slidable on the upper surface of the horizontal guide plate 36 fixed to the apparatus substrate 1. The cam rollers 37, 37 are pivotally supported on both sides of the mounting base 35. Between the cam rollers 37, 37 and the vertical plate 31, a pressurizing cam plate 39 that is driven up and down by an air cylinder 38 installed on the apparatus substrate 1, the cam surface 39 a of which is the cam roller 37, 37, and the opposite side surface 39b is interposed so as to be in sliding contact with the vertical plate 31. The air cylinder 38 is attached to the apparatus substrate 1 via the bracket 40. Reference numeral 41 denotes a lock nut that fixes the cam roller mounting base 35 to a fixed position of the pressure drive shaft 29.
[0021]
In the operation of the pressurizing mechanism 4 having the above-described configuration, the cam plate 39 is lowered to the position shown by the solid line in FIG. 1 by the air cylinder 38 so that the movable base 3 is not pressed. Therefore, when pressurizing the workpiece W in the axial direction during welding, the cam plate 39 is moved up to the position indicated by the phantom line in FIG. As the cam plate 39 moves upward, the cam rollers 37, 37 that are in pressure contact with the cam surface 39a move horizontally, and at the same time, the cam roller mounting base 35 slides on the horizontal guide plate 36, and The pressure drive shaft 29 presses and moves the movable table 3 by a required amount in the direction approaching the fixed table 2 (right direction) via the steel ball 34, thereby clamping by the clamp mechanism 11 on the movable table 3 side. The material to be welded W and the material to be welded W clamped by the clamp mechanism 10 on the fixed base 2 side are pressed against each other in the axial direction.
[0022]
In FIG. 1 and FIG. 2, reference numeral 42 denotes a stopper that restricts the movement of the movable table 3 by the pressing operation of the pressurizing mechanism 4 and is provided on the apparatus substrate 1 side. As shown in FIGS. 1 and 2, the stopper 42 is attached to a bracket b fixed to the apparatus substrate 1 so that the stopper mounting base c can be moved in the horizontal direction, and a stopper piece a made of a bolt is attached to the stopper mounting base c. It is screwed so that it can be moved in the horizontal direction, and the end surface of the movable table 3 is brought into contact with the tip of the stopper piece a to limit the amount of movement of the movable table 3 (that is, the amount of pressurization). Yes. In this case, the stopper mounting base c can be attached to the bracket b so that the movement in the horizontal direction can be adjusted by providing an elongated hole d in the stopper mounting base c and screwing a bolt e into the bracket b from the elongated hole d.
[0023]
Therefore, the position of the stopper 42 can be adjusted relatively greatly by the stopper mounting base c, and can be finely adjusted by appropriately rotating the stopper piece a screwed to the stopper mounting base c. In the pressurizing mechanism 4 of this embodiment, the position adjustment of the stopper 42 is manually performed. However, for example, a system in which a ball screw is rotationally driven by a motor can be automatically performed. It can be done. In the pressurizing mechanism 4, the applied pressure (pressing force) is adjusted by appropriately rotating the spring pressure adjusting member 32 screwed to the pressurizing drive shaft 29 to adjust the spring pressure of the coil spring 33. .
[0024]
Moreover, although the tip electrodes 13 and 18 shown in FIGS. 4-6 show the structure in the case of joining both to-be-welded materials W and W which should be welded linearly, they were formed in the shape of a curve, for example When welding both the workpieces W ′ and W ′, or when welding both ends of a single workpiece W ′ formed in a curved shape, as shown in FIGS. As shown, the half-divided bodies 13a, 13b, 18a, 18b of the chip electrodes 13, 18 are each provided with a semicircular fitting groove 42 having a curved section in plan view corresponding to the shape of the curved workpiece W ′. What is necessary is just to form.
[0025]
In this welding apparatus, the hood 24 is disposed at the opposite end of the electrode 8 on the fixed base 2 side and the electrode 9 on the movable base 3 side in order to block the periphery of the joint portion of the workpieces W and W from outside air. Although it is attached, instead of using such a hood 24, a heat-resistant and electrically insulating reflecting plate is provided on the opposite side of the torch 26 across the butting position P of the two workpieces W, W, or A plurality of, for example, 3 to 4 torches 26 may be arranged radially around the butting position P of the two workpieces W, W. If the hood 24 as in this embodiment is used, the periphery of the joint portion of both the welded materials W and W can be surely shielded from the outside air, and the mounting is simple and easy.
[0026]
FIG. 11 shows a schematic configuration of the whole welding apparatus and its electric circuit. In this figure, 43 is a heating transformer, MS is a heating switch, 44 is a high-frequency generator for TIG welding, and 45 is A control device 46 is a welding power source. FIG. 13 shows a sequence circuit of the control device 45.
[0027]
Next, a method for welding the linear workpiece W using the above welding apparatus will be described with reference to a welding process diagram of FIG. 7, a sequence circuit of FIG. 13, and a sequence time chart of FIG.
[0028]
First, with both clamp mechanisms 10 and 11 on the fixed base 2 side and the movable base 3 side opened (clamp release), as shown in FIG. Both the workpieces W and W are disposed in the chip electrodes 13 and 18 and their opposed end faces are butted. Next, as shown in FIG. 13, when the push button PB1 (for example, foot switch) is pressed, the relay coil CR1 is excited and the contact is closed, and the clamp cylinder 17 of the clamp mechanism 10 is clamped, and is fixed by the timer T1. After a lapse of time, the clamp cylinder 17 is locked, and the workpiece W on the right side is clamped via the tip electrode 13 on the fixed base 2 side. Then, when the push button PB2 is pressed, the relay coil CR2 is excited and the contact is closed, and the clamp cylinder 22 of the clamp mechanism 11 on the movable base 3 side (left side in FIG. 1) is clamped, and a certain time elapses by the timer T2. Later, the clamp cylinder 22 is locked, and the workpiece W on the left side is clamped via the tip electrode 18 on the movable table 3 side. FIG. 7B shows the clamped state of both workpieces W and W. FIG.
[0029]
The relay coil CR3 is energized by the timer T2 to close its contact, and the inert gas is released after a lapse of a certain time by the operation of the timer T3 and is supplied into the hood 24 through the torch 26, and the air in the hood 24 is expelled. It is. Subsequently, the relay coil CR4 is excited by the timer T3 and its contact is closed, and the pressurizing mechanism 4 is activated after a predetermined time has elapsed by the operation of the timer T4. , W are pressed in the opposite direction, and the pressed state is shown in FIG.
[0030]
Next, the timer T4 is activated after a certain time, the relay coil CR5, the timer T5, and the timer T6 are excited, the heating switch MS is closed by energization of the relay coil CR5, and heating is started. That is, an electric current (for example, 20 A / mm) is applied to the joint portion of the workpieces W and W via the external electrode pieces 14, 15, 19 and 20 and the tip electrodes 13 and 18. ² ) And heating of the joint is started by the resistance heat generation. Then, the relay coil CR6 is excited by the operation of the timer T5 after a certain period of time, and the contact is closed, thereby completing the heating. At the time when this heating is finished (or just before it is finished), the relay coil CR7 and the timer T7 are excited by the timer T6, and the relay coil CR10 is excited and the discharge is started. Then, the relay coil CR8 is demagnetized after a certain time by the timer T7, the contact of the relay coil CR10 is opened, and the discharge is stopped. At the same time, the timer T7 is excited by the timer T7, the relay coil CR9 is excited after a certain time, the contact is opened, welding is completed, and the relay circuit returns to the original state.
[0031]
A specific example of each operation time in the series of welding processes described above is as shown in the sequence time chart of FIG. In this figure, the residual heat time is a holding time (for example, 3 seconds) after the end of welding.
[0032]
As described above, in this welding method, both welded materials W and W are lightly abutted on the coaxial line, and then the periphery of the joint portion of both welded materials W and W is covered with the hood 24 in an inert gas atmosphere. In this state, while pressurizing both workpieces W and W in the axial direction, a current is passed between the workpieces W and W until the joint is melted, and then heated in an inert gas atmosphere. Since this is a method in which arcs are discharged at the joint portions of the two welded materials W and W to join the two welded materials, the welded portions cannot be drawn (concave portions) unlike conventional TIG welding. That is, according to the method of the present invention, even if the butt end surfaces of the workpieces W are uneven or inclined and a gap is formed between the butt end surfaces, both of the workpieces W, W By heating the welded materials W and W to a certain amount in the axial direction while heating them until just before the joining part melts, and by discharging an arc to the joining part after heating, the uneven part and the inclined part on the butt end face 8 is naturally crushed so as to fill the gap between the butt end faces, and therefore cannot be retracted as seen in TIG welding, and as shown in FIG. Becomes almost the same diameter as the diameter of the workpiece W. In this case, the amount of pressurization for pressurizing both the workpieces W, W in the axial direction can be appropriately set by adjusting the position of the stopper 42 in accordance with the form of the butted end surfaces of the two workpieces W. it can. That is, if there are many gaps between the butt end surfaces of the workpieces W and W, the amount of pressurization, that is, the amount of movement of the movable table 3 should be increased accordingly, and if the gap is small, the movable table The movement amount of 3 may be reduced. Thereby, the amount of penetration can be adjusted as desired according to the unevenness and inclination state of the workpiece W, and extremely good welding without shrinkage and burrs can be performed.
[0033]
Further, according to this welding method, the occurrence of poor penetration and internal defects, which are problems in conventional TIG welding, are eliminated. That is, after heating the welded materials W, W to the non-molten state by resistance heating while pressing both welded materials W, W in the axial direction in a state where the periphery of the joint portion of the welded materials W, W is in an inert gas atmosphere, The arc is discharged into this non-molten joint, the joint is well melted and can be completely fused to the inside, and the melt is uniform not only on the discharge side by the torch but on the entire circumference of the joint. Therefore, the entire welded portion becomes homogeneous, the strength of the welded portion can be increased, and the heating and arc discharge are both performed in an inert gas atmosphere, so that oxidation of the welded portion is prevented. Thus, good welding can be obtained without discoloration or alteration.
[0034]
Further, in this welding method, while heating both welded materials W, W in a fixed amount in the axial direction as described above, after heating until just before melting the joint through the current between the welded materials W, W, Since the arc is discharged and welded, no burrs are observed as seen in conventional butt welding, and as shown in FIG. Almost unchanged, a good weld is formed.
[0035]
In addition, although not shown in the above-described welding apparatus, an apparatus for adjusting the current intensity and the energization time for arc energization to immediately energize until the joint between the welded materials W and W is melted, and arc discharge A device for adjusting the strength and discharge time of the battery is provided. Therefore, according to this welding apparatus, the position of the stopper 42 is adjusted, the strength of the current applied to the joint portion of the workpieces W and W, the energization time, and the arc discharge discharged to the joint portion. By adjusting the strength and the discharge time as desired, it is possible to perform extremely good welding with no shrinkage or burrs.
[0036]
【The invention's effect】
According to the welding method of the first aspect of the present invention, both the welded materials are pressed in a certain amount in the axial direction while being heated until just before the welded portions of both welded materials melt, and an arc is applied to the joined portions after the heating. Even if the butt end surfaces of the welded materials have irregularities or inclined surfaces, and there are gaps between the butt end surfaces, in order to cause discharge, the rugged portions or inclined portions of the butt end surfaces Melts naturally so as to fill the gap between the butt end faces, and the joint part is uniformly fused.Therefore, the joint end part of the welded material cannot be attracted as seen in TIG welding. Good welding with almost the same diameter can be performed.
[0037]
Further, there is no occurrence of poor penetration and internal defects, which are problems in conventional TIG welding. That is, while pressurizing the joints of both workpieces in the axial direction, prior to arc discharge, they are preheated to the non-molten state by resistance heat generation, and then the arc is discharged to the non-molten joints. The penetration of the joint is good and it is possible to fuse completely to the inside, and the penetration is uniform not only on the discharge side but on the entire circumference of the joint, so the whole weld is homogeneous and the strength of the weld Can be increased. In addition, since both the heating and the arc discharge are performed in an inert gas atmosphere, oxidation of the welded part during the heating and arc discharge is prevented, and a good weld without discoloration or alteration is obtained.
[0038]
Furthermore, while pressing both welded materials in the axial direction, the joints of both welded materials are heated up to just before melting, and then the arc is discharged and welded. It does not occur and is almost the same as the diameter of the workpiece W, and a good weld is formed. Therefore, the strength of the weld is increased and the appearance and appearance are improved.
[0039]
According to claim 2, by causing the arc discharge to be performed by the tungsten electrode that generates an arc with the material to be welded, the consumption of the electrode is small even with high-temperature arc heat, and the stability of the arc is good. Become.
[0040]
According to the third aspect of the present invention, arc discharge can be performed extremely effectively by forming an inert gas atmosphere by blocking the periphery of the joint portion between the welded materials from the outside air.
[0041]
According to the welding apparatus of the fourth aspect, the welding method according to the first aspect can be effectively carried out, and thereby the effects described in the first aspect can be achieved. In particular, since this welding apparatus includes a stopper that restricts the movement of the movable table due to the pressing of the pressurizing mechanism, the position of this stopper is determined by the shape of the butted end surfaces of both welded materials and the diameter of the welded materials. By adjusting according to the above, etc., it is possible to adjust the amount of pressurizing both welded materials in the axial direction, thereby adjusting the amount of penetration as desired. By adjusting the strength and discharge time of the current to be passed through and the strength and discharge time of the arc discharge discharged to the joint as desired, extremely good welding without shrinkage and burrs can be performed. .
[0042]
According to the fifth aspect, the current from the tip electrode flows from the tip portion of each tip electrode to each material to be welded, whereby the current can be concentrated and flowed efficiently at the joining end portion of each material to be welded. At the same time, damage to each chip electrode can be prevented.
[0043]
According to the sixth aspect of the present invention, by attaching a hood that surrounds the joint portion of both welded materials and blocks outside air to the opposite end portions of the fixed base side electrode and the movable base side electrode, The periphery of the joint can be reliably blocked from the outside air.
[0044]
According to the seventh aspect, it is easy and easy to attach the hood to the tip electrode, and there is no problem even if the tip electrode on the movable base moves when the movable base is pressurized.
[Brief description of the drawings]
FIG. 1 is an overall front view showing a welding apparatus according to the present invention.
FIG. 2 is a cross-sectional view taken along line XX in FIG.
3 is a cross-sectional view taken along line YY in FIG.
4A is a front view showing an electrode on a fixed base side, and FIG. 4B is a sectional view taken along line ZZ of FIG. 4A.
FIG. 5 is an exploded perspective view showing a chip electrode.
6A is a front view showing an electrode on the movable base side, and FIG. 6B is a right side view of FIG. 6A.
FIGS. 7A to 7D are explanatory views showing a welding process. FIGS.
FIG. 8 is a front view showing a material to be welded welded by the method of the present invention.
9A is a front view of a workpiece to be welded by conventional TIG welding, and FIG. 9B is a front view of the workpiece to be welded by conventional butt welding.
FIG. 10A is a perspective view showing a state in which a curved workpiece is set on a tip electrode, and FIG. 10B is a plan view showing a state in which one half of the tip electrode is removed.
FIG. 11 is an overall schematic configuration diagram of a welding apparatus according to the present invention.
FIG. 12 is a sequence time chart in welding by using the above welding apparatus.
FIG. 13 is a sequence circuit diagram of the above welding apparatus.
[Explanation of symbols]
W Welded material
1 Device board
2 fixed base
3 Movable stand
4 Pressurization mechanism
5 Guide rail
6 Guide rail
8 Electrode on the fixed base side
9 Movable stand side electrode
10 Clamp mechanism on the fixed base side
11 Movable stand side clamp mechanism
12 Welding material fitting groove
12a Deep groove
13 Chip electrode on the fixed base side
18 Tip electrode on movable platform
24 food
24a halves
26 Torch
27 Tungsten electrode
42 Stopper
45 Controller
46 Welding power source

Claims

Both welded materials to be welded are butted on the same line, and then the area around the joint between the welded materials is set to an inert gas atmosphere. And heating the joint until immediately before melting, and then discharging the arc to the joint of the two welded materials in the inert gas atmosphere to join the two welded materials.

The welding method according to claim 1, wherein the arc discharge is performed by a tungsten electrode that generates an arc with a workpiece.

The welding method according to claim 1 or 2, wherein an inert gas atmosphere is formed by blocking the periphery of the joint portion of both welded materials from the outside air.

A fixed base and a movable base are arranged on both sides in the longitudinal direction of the material to be welded, with the butting positions of the two materials to be welded being sandwiched, and the material to be welded is connected to each of the fixed base and the movable base via welding current supply electrodes A clamping mechanism is provided for clamping the welded material, supplying an inert gas toward the welded portion of both workpieces to create an inert gas atmosphere around the welded portion and discharging an arc to the welded material joints. And a pressurizing mechanism for pressing the movable base in a direction approaching the fixed base and pressurizing both workpieces in the axial direction, and for restricting the movement of the movable base due to the press of the pressurizing mechanism A welding apparatus comprising a position-adjustable stopper and a welding power source.

Each electrode on the fixed base side and the movable base side includes a tip electrode composed of a pair of upper and lower halves that are vertically divided into two parts to form a welded material fitting groove into which the welded material is fitted. The welding apparatus according to claim 4, wherein the welding material fitting groove of each chip electrode is formed with a deep groove at an intermediate portion so that only the both ends in the longitudinal direction of the inner peripheral surface thereof are in contact with the welding material.

The welding apparatus according to claim 4 or 5, wherein a hood that surrounds the joint portion of both of the welded materials and blocks outside air is attached to opposing ends of the fixed base side electrode and the movable base side electrode.

The hood is formed in a cylindrical shape that can be externally fitted to each chip electrode, and is composed of a pair of halves that are vertically divided into two halves. It is fitted and fixed to the tip of the electrode half, and the other end of each of the halves is fitted to the tip of the movable chip electrode half so as to be axially slidable. The welding apparatus according to claim 6.