JP4596642B2

JP4596642B2 - Arc spraying method and apparatus

Info

Publication number: JP4596642B2
Application number: JP2000402318A
Authority: JP
Inventors: 宏平有坂; 鉄也永島; 元辻井
Original assignee: Daihen Corp
Current assignee: Daihen Corp
Priority date: 2000-12-28
Filing date: 2000-12-28
Publication date: 2010-12-08
Anticipated expiration: 2020-12-28
Also published as: JP2002206159A

Description

【０００１】
【発明の属する技術分野】
本発明は、アークにより溶融させた金属を霧化して被溶射物に吹き付けることにより、被溶射物の表面に金属の被膜を形成するアーク溶射方法及びアーク溶射装置に関するものである。
【０００２】
【従来の技術】
港湾施設、橋梁、鉄塔等、屋外に設置される設備の構成部材においては、その表面に防錆用の被膜や耐蝕性を有する被膜を形成することが多い。
【０００３】
素材または製品の表面に耐蝕性の被膜を形成する方法の一つとして、アーク溶射方法が知られている。アーク溶射方法においては、溶射方向に沿う軸線（以下溶射軸線という。）上に設定した目標点に先端が指向する２本の線材ガイド管と、目標点の近傍にガスを供給する手段とを備えた溶射ヘッドを用い、両線材ガイド管によりそれぞれ２本の溶射用線材をガイドしつつ目標点に向けて送給して、２本の線材ガイド管の先端からそれぞれ突出した２本の溶射用線材の先端を目標点付近で接触させる。そして、両線材間に電圧を印加することにより、両線材の先端部の間でアークを発生させて、両線材の先端部を溶融させ、溶融した線材の先端部にガス流を吹き付けることにより溶融した線材を霧化して溶融金属の噴霧流を形成する。この噴霧流を溶射方向の前方に配置した被溶射物に吹き付けて、該被溶射物の表面に金属の被膜を形成する。上記２本の線材として異種の金属からなるものを用いると、異種の金属の合金の被膜を形成することができる。
【０００４】
防錆用の被膜や耐蝕性を有する被膜を形成する場合、上記２本の線材としては、例えば亜鉛線とアルミニュウム線とが用いられる。
【０００５】
従来のアーク溶射方法においては、アークにより溶融させられた線材の先端部に向けて、溶射軸線に沿って流れる一次ガス流を生じさせるとともに、線材ガイド管の先端から突出した線材が配置された領域を内包した状態で目標点よりも手前の位置から目標点よりも更に前方の位置に設定された溶射軸線上の集束点に向けて集束するように流れる二次ガス流を発生させ、一次ガス流を線材の先端部に吹き付けることにより溶融金属の噴霧流を形成した後、この噴霧流を外側から包み込むように流れる二次ガス流により集束させつつ、溶射方向の前方に噴出させるようにしていた。
【０００６】
【発明が解決しようとする課題】
従来のアーク溶射方法では、一次ガス流を溶射軸線に沿って流すようにしていたため、一次ガス流の風量を増加させ、風速を増大させると、２本の線材の先端間に発生したアークのアーク長が長くなり、アークが不安定になるという問題があった。
【０００７】
特に亜鉛のような融点が低い金属からなる線材を用いて溶射を行う場合には、線材間に低い電圧を印加してアークを発生させるが、この場合に溶射軸線に沿ってアークに強いガス流を吹き付けるとアーク長が長くなって、アークのとぎれを生じやすい。
【０００８】
また特開平１１−２７９７４３号に示されているように、２本の線材ガイド管が配置されたヘッド内の空間（孔部）全体を通して一次ガス流を流すようにしたものもあるが、このように構成した場合には、一次ガス流の中心部に２本の線材が配置される形になるため、２本の線材の先端部の溶融部分に集中的に一次ガス流を吹き付けることができず、溶融金属の霧化を効率よく行うことが難しいという問題があった。
【０００９】
また従来のアーク溶射方法では、２本の線材の先端の溶融部分に十分な流速を持った一次ガスを吹き付けることが困難であるため、霧化した金属が２本の線材の先端付近を浮遊して線材ガイドの先端部に付着し、長時間溶射を行うと、線材ガイドの先端に付着した金属により線材のスムーズな供給が妨げられたり、ガスの流れが乱されたりするという問題があった。
【００１０】
本発明の目的は、アークを安定に維持して動作を安定にするとともに、溶融金属の霧化を効率よく行うことができるようにしたアーク溶射方法を提案することにある。
【００１１】
本発明の他の目的は、溶融した金属が線材ガイドの先端部に付着して、線材のスムーズな供給を妨げたり、ガス流を乱したりするのを防ぐことができるアーク溶射方法を提供することにある。
【００１２】
本発明の更に他の目的は、上記の溶射方法を実施するアーク溶射装置を提供することにある。
【００１３】
【課題を解決するための手段】
本発明に係わるアーク溶射方法においては、２本の溶射用線材を、溶射軸線上に設定された目標点に先端が指向する２本の線材ガイド管によりそれぞれガイドしつつ目標点に向けて送給して、２本の線材ガイド管の先端からそれぞれ突出した２本の溶射用線材の先端を目標点付近で接触させるとともに、２本の線材間に電圧を印加して両線材の先端間でアークを発生させる。また上記目標点付近に一次ガス流の集合点を設定して、２本の線材ガイド管が設けられた領域の周囲の複数個所から溶射軸線に対して傾斜した方向に沿って集合点に向う複数のビーム状の一次ガス流を発生させるとともに、２本の線材ガイド管から突出した線材が配置された領域を内包した状態で目標点よりも手前の位置から目標点よりも更に前方の位置に設定された溶射軸線上の集束点に向けて集束するように流れる二次ガス流を発生させる。上記一次ガス流を２本の線材の先端のアークにより溶融した部分に集中的に吹き付けることにより溶融金属の噴霧流を形成し、該噴霧流を二次ガス流とともに溶射方向の前方に配置した被溶射物に向けて噴出させることにより溶射を行う。
【００１４】
上記のように、２本の線材ガイド管が設けられた領域の周囲の複数個所から溶射軸線に対して傾斜した方向に沿って集合点に向う複数のビーム状の一次ガス流を発生させるようにすると、線材のアークにより溶融した部分に集中的にガスを吹き付けることができるため、アークが引き伸ばされるのを防いでアークを安定に維持しつつ効率よく溶融金属の噴霧流を生じさせることができる。
【００１５】
本発明の好ましい態様では、溶射方向に沿う軸線に中心軸線が一致するように設けられて先端が溶射方向の前方側に開口した孔部を内側に有する環状部材と、中心軸線が溶射軸線に一致し、かつ溶射軸線上に設定された集束点に集束する方向に沿うように傾斜した状態で孔部を連続的または断続的に取り囲むように設けられて先端が溶射方向の前方側に開口したオリフィスとを備えたヘッド本体と、環状部材の孔部を貫通して先端が該孔部の開口位置付近で終端するように設けられて、孔部の開口位置と集束点との間に位置させて溶射軸線上に設定された目標点に向けて溶射用線材を案内するように構成された２本の線材ガイド管とを備えた溶射ヘッドと、２本の線材の先端間でアークを発生させるために両線材間に給電する給電手段とを設けてアーク溶射を行う。
【００１６】
この場合も、上記目標点付近に一次ガス流の集合点を設定しておき、ヘッド本体の孔内の２本の線材ガイド管が配置された領域よりも外側の領域の複数個所から溶射軸線に対して傾斜した流路に沿って集合点に向うビーム状の一次ガス流を複数生じさせるとともに、オリフィスから噴出して集束点に向けて流れる二次ガス流を生じさせる。そして、一次ガス流を２本の線材の先端のアークにより溶融した部分に集中的に吹き付けることにより溶融金属の噴霧流を生じさせ、該噴霧流を二次ガス流とともに溶射方向の前方に配置した被溶射物に向けて噴出させることにより溶射を行う。
【００１７】
上記のアーク溶射方法を行う際には、複数の一次ガス流の内の少なくとも一部の一次ガス流を２本のガイド管の先端部付近に接触させるようにするのが好ましい。
【００１８】
このように一次ガス流の少くとも一部を線材ガイド管に接触させるようにすると、線材ガイド管を冷却して線材ガイド管のアーク熱による膨脹を抑制し、線材ガイド管と線材との間の隙間の変化を少くすることができるため、ガイド管を通して目標点に向けて送給される線材の揺れを少くして、アークの安定化を図ることができる。
【００１９】
また上記のようにビーム状の一次ガス流を生じさせて該一次ガス流を２本の線材の先端の溶融部分に吹き付けるようにすると、線材の溶融部分に吹き付けられるガスの流速を速くすることができるため、霧化した溶融金属を線材の先端付近に滞留させることなく、前方に移動させて、二次ガス流にのせて送り出すことができる。そのため、線材ガイドの先端部に溶融金属が付着するおそれをなくすことができ、線材ガイドの先端部に付着した金属により線材のスムーズな供給が妨げられたり、線材ガイドの先端部付近のガスの流れが乱されたりするのを防ぐことができる。
【００２０】
本発明においてはまた、２本の線材ガイド管のそれぞれの長手方向に沿うように形成されて先端が前記目標点側に開口させられた一次ガス流路を設けて、２本の線材ガイド管のそれぞれの長手方向に延びる一次ガス流路からそれぞれ流出させた一次ガス流を２本の線材に沿って両線材の先端付近の溶融部分に吹き付けることによって溶融金属の噴霧流を生じさせるようにしてもよい。
【００２１】
この場合も、２本の線材の先端部間で発生するアークが引き伸ばされるのを防ぎつつ、線材の先端の溶融部分に集中的にガスを吹き付けることができるため、効率よく溶融金属の噴霧流を生じさせることができる。
【００２２】
また上記のように構成すると、一次ガス流により線材ガイド管を冷却することができるため、線材ガイド管のアーク熱による膨脹を抑制して、線材ガイド管と線材との間の隙間の変化を少くし、ガイド管を通して送給される線材の揺れを少くして、アークの安定化を図ることができる。
【００２３】
更に上記のように構成した場合も、線材の溶融部分に十分に大きな流速をもつ一次ガスを集中的に吹き付けて、霧化した溶融金属を前方に移動させることができるため、線材ガイドの先端部付近に溶融金属が付着するのを防ぐことができる。
【００２４】
溶融した線材に一次ガス流を吹き付けて溶融金属を霧化する場合、溶融金属に吹き付ける一次ガス流の流速の最適値は、溶射用線材の材質や線径等に応じて相違する。したがって、一次ガス流の流速は、溶射用線材の種類に応じて適値に設定するのが好ましい。
【００２５】
本発明に係わるアーク溶射装置は、溶射軸線に中心軸線が一致するように設けられて先端が溶射方向の前方側に開口した孔部を内側に有する環状部材と、中心軸線が溶射軸線に一致し、かつ溶射軸線上に設定された集束点に集束する方向に沿うように傾斜した状態で孔部を連続的または断続的に取り囲むように設けられて先端が溶射方向の前方側に開口したオリフィスと該オリフィスの後端部に連通させられたガス溜め室とを備えたヘッド本体と、環状部材の孔部を貫通して先端が前記孔部の開口位置付近で終端するように設けられて、前記孔部の開口位置と前記集束点との間に位置させた状態で前記溶射軸線上に設定された目標点に向けて溶射用線材を案内するように構成された２本の線材ガイド管と、環状部材の内側で溶射方向の前方側に流れる一次ガス流を生じさせる一次ガス流形成手段とを備えた溶射ヘッドと、オリフィスから二次ガスを噴出させるためにガス溜め室に圧縮された二次ガスを供給する二次ガス供給手段と、２本の線材の先端間でアークを発生させるために両線材間に給電する給電手段とを備えたものである。
【００２６】
本発明においては、２本の線材の先端付近と線材ガイド管の先端付近との間に位置させた状態で溶射軸線上に一次ガス流の集合点が設定される。一次ガス流形成手段は、環状部材の内側の孔部内の２本の線材ガイド管が配置された領域よりも外側の領域の複数個所から溶射軸線に対して傾斜した方向に沿って集合点に向って流れて２本の線材の先端のアークにより溶融した部分に集中的に吹き付けられる複数のビーム状の一次ガス流を生じさせるように、溶射軸線に対して傾斜した状態で設けられて先端が孔部内で集合点に指向させられた複数の一次ガス流路により構成される。
【００２７】
上記複数の一次ガス流路の内の少なくとも一部の一次ガス流路は、２本のガイド管の先端部付近に接触して流れる一次ガス流を生じさせるように設けられる。本発明の好ましい実施態様では、上記２本の線材ガイド管が、それぞれのガイド方向に沿う中心線を環状部材の中心軸線を含む平面上に位置させた状態で設けられる。また一次ガス流路は、環状部材の中心軸線の回りに９０度間隔で４つ設けられ、該４つの一次ガス流路の内の２つの一次ガス流路が、それぞれの中心線を２本の線材ガイド管の中心線が配置された平面上に位置させた状態で設けられる。
【００２８】
上記のように構成すると、２本の線材ガイド管の中心軸線が配置された平面上に中心線を位置させた２つの一次ガス流路により、各線材ガイド管に接触して流れる一次ガス流を生じさせて各線材ガイド管を冷却することができるため、各線材ガイド管の熱膨脹を抑制して線材の揺れを少くし、アークの安定化を図ることができる。
【００２９】
上記のように一次ガス流路を、溶射軸線の回りに９０度間隔で４つ設けて、これらの一次ガス流路により生じさせた一次ガス流をアーク点に集中的に吹き付けるためには、対角位置にある各２つの一次ガス流路を、それぞれの中心線を、２本の線材ガイド管の中心線が配置された平面に対して４５度傾いた平面上に位置させた状態で設けるのが好ましい。
【００３０】
このように一次ガス流路を設けると、４つの一次ガス流路を通してそれぞれ流れる一次ガスを２本のガイド管にほとんど妨げられることなく、しかもアークにより加熱されるガイド管の先端部付近に接触させつつアーク点に向わせることができるため、線材の先端部付近に吹き付けるガスの量を多くして溶融金属の霧化を効率よく行わせるとともに、線材ガイド管の温度上昇を抑制して線材の送給を安定化し、アークを安定に維持することができる。
【００３１】
本発明の他の好ましい実施態様では、２本の線材ガイド管の長手方向に沿うように形成されて先端が前記目標点側に開口させられた一次ガス流路と、各線材ガイド管の長手方向に沿う一次ガス通路に圧縮された一次ガスを供給する一次ガス供給手段とが設けられる。
【００３２】
このように構成すると、一次ガス流は、各線材ガイド管の先端から線材に沿って流れて、２本の線材の先端の溶融部分に集中的に吹き付けられるため、溶融金属の霧化を効率よく行わせることができる。
【００３３】
上記のように各線材ガイド管の長手方向に沿うように一次ガス通路を形成する場合には、ガスの流れを安定にするため、該一次ガス通路は、各線材ガイド管がガイドする線材を同軸的に取り囲むように形成するのが好ましい。
【００３４】
【発明の実施の形態】
以下図面を参照して本発明の好ましい実施形態を説明する。図１及び図２は本発明に係わるアーク溶射方法において用いる溶射ヘッドの好ましい構成例を示したもので、図１は同溶射ヘッドの縦断面図、図２はその正面図である。図１及び図２に示した溶射ヘッド１は、溶射軸線Ｏ−Ｏに中心軸線が一致するように設けられて先端が溶射方向の前方側に開口した孔部２００を内側に有する環状部材２と、該環状部材２に取りつけられた第１及び第２の筒体３及び４と、第１及び第２の線材ガイド管５Ａ及び５Ｂとを備えている。
【００３５】
環状部材２は、溶射軸線Ｏ−Ｏに中心軸線が一致した円筒面状の外周面を有する環状の主部２０１と、該主部２０１の内周側から軸線方向の一方の側に突出した截頭円錐状の突出部２０２とを有する金属製の部材からなっていて、主部２０１及び突出部２０２の内周面２０３は、溶射軸線Ｏ−Ｏ線に中心軸線が一致した連続する截頭円錐面となっている。内周面２０３は、溶射方向の前方側に向って次第に径が小さくなる向きに傾斜するように設けられていて、この内周面２０３の内側の空間が孔部２００となっている。また環状部材２の突出部２０２の外周面は中心軸線が溶射軸線Ｏ−Ｏに一致した截頭円錐状のガス案内面２０４となっている。環状部材２０１の軸線方向の一端から他端寄りの部分の外周には第１の雄ネジ部２０５が、また環状部材２０１の軸線方向の他端寄り部分の外周には第２の雄ネジ部２０６がそれぞれ形成され、第１の雄ネジ部２０５と第２の雄ネジ部２０６との間には、突条部２０７が周設されている。
【００３６】
環状部材２の主部２０１の内周寄りの部分には、内周面２０３と同じ側に、かつ内周面２０３よりも大きな傾斜角をもって溶射軸線Ｏ−Ｏに対して傾斜した孔からなる一次ガス流路２０８が、周方向に９０度の間隔をあけて（溶射軸線の回りに４等配で）４つ形成されている。各一次ガス流路２０８は、その先端側の開口部２０８ａが孔部２００の先端側の開口部２００ａを通して、後記するように設定された一次ガス流Ｇ1 の集合点Ａに指向し、後端部側の開口部２０８ｂが環状部材２の軸線方向の他端側の端面に開口するように設けられている。
【００３７】
第１の筒体３は、周壁部３０１と該周壁部の軸線方向の一端側に形成された端部壁３０２とを有する金属製の円筒体からなっていて、周壁部３０１の内周に形成された雌ネジ部３０３が環状部材２の外周の第１の雄ネジ部２０５に螺合されて環状部材２に固定されている。第１の筒体３の端部壁３０２の中央部には、環状部材２の突出部２０２の外周に形成されたガス案内面２０４と同じ側に傾斜して、ガス案内面２０４を一定の間隙を介して取り囲む内周面を有する開口部３０４が形成され、この開口部３０４の内周面とガス案内面２０２との間に形成された隙間により、環状部材２と中心軸線を共有し、かつ溶射軸線Ｏ−Ｏ上に設定された集束点Ｂに集束する方向に沿うように傾斜した状態で孔部２００を連続的に取り囲むオリフィス６が形成されている。
【００３８】
第１の筒体３と、環状部材２との間にガス案内面２０４を取り囲む環状のガス溜め室７が形成され、このガス溜め室７がオリフィス６の後端部に連通させられている。コンプレッサ等の図示しない二次ガス供給手段から第１の筒体３の周壁部を貫通した孔に接続された二次ガス流供給管８を通して、ガス溜め室７に圧縮された二次ガス（通常は空気）が供給され、ガス溜め室７内からオリフィス６を通して集束点Ｂに向う二次ガス流Ｇ2 が生じさせられる。
【００３９】
第２の筒体４は、円筒状の外側壁部４０１と、外側壁部４０１よりも軸線方向寸法が短い円筒状の内側壁部４０２と、これらの壁部の軸線方向の一端側に跨って形成された端部壁４０３とを有していて、外側壁部４０１の内周に形成された雌ネジ部４０４が環状部材２の外周に形成された第２の雄ネジ部２０６に螺合され、内側壁部４０２の軸線方向の他端が環状部材２の軸線方向の他端側の端面の内周寄りの部分にパッキン等の気密保持手段を介して当接させられている。第２の筒体４と環状部材２との間に溶射軸線Ｏ−Ｏを取り囲む環状のガス溜め室９が形成され、環状部材２に設けられた各一次ガス流路２０８がこのガス溜め室９内に連通させられている。ガス溜め室９内には、第２の筒体４の外側壁部４０１を貫通した孔に接続された一次ガス供給管１０を通して、圧縮された一次ガス（通常は空気）が供給され、ガス溜め室９から各一次ガス流路２０８を通して集合点Ａに向うビーム状の一次ガス流Ｇ1 が生じさせられる。この例では、ガス溜め室９と一次ガス流路２０８と、ガス溜め室９に圧縮された一次ガスを供給する一次ガス供給手段（図示せず。）とにより、環状部材２の内側で溶射方向の前方側に流れる一次ガス流Ｇ1 を生じさせる一次ガス流形成手段が構成されている。一次ガス流の流速を適宜に変化させるため、一次ガス供給手段は、ガス溜め室９に供給する一次ガスの圧力を変化させ得るように構成されている。
【００４０】
上記環状部材２と第１及び第２の筒体３及び４とにより、オリフィス６と、該オリフィスに連通したガス溜め室７とを有するヘッド本体が構成されている。
【００４１】
第１の線材ガイド管５Ａ及び第２の線材ガイド管５Ｂは、環状部材２の孔部２００内を溶射軸線Ｏ−Ｏと平行に伸びる直管部５０１と、該直管部の先端から溶射軸線Ｏ−Ｏ側に折れ曲がった屈曲部５０２とを有する金属製の管からなっていて、それぞれの内部の軸芯部を長手方向に貫通した状態で溶射用線材１１Ａ及び１１Ｂをガイドするガイド孔ｈが形成されている。
【００４２】
第１及び第２の線材ガイド管５Ａ及び５Ｂは、それぞれのガイド方向に沿う中心線（それぞれがガイドする線材１１Ａ及び１１Ｂの長手方向に沿う中心軸線）を溶射軸線Ｏ−Ｏを含む平面上に位置させるとともに、それぞれの先端を孔部２００の先端の開口部２００ａ付近で終端させ、かつそれぞれがガイドする線材１１Ａ及び１１Ｂの先端を、環状部材２の孔部２００の開口位置Ｐと前記集束点Ｂとの間に位置させて溶射軸線Ｏ−Ｏ上に設定された目標点Ｃに指向させるように設けられている。
【００４３】
溶射用線材１１Ａ及び１１Ｂは、押えローラと送給ローラとからなる送給機構により送給されて線材ガイド管５Ａ及び５Ｂに送り込まれ、これらのガイド管５Ａ及び５Ｂによりガイドされつつ目標点Ｃに向けて送給されて、該目標点Ｃ付近でそれぞれの先端が接触する。
【００４４】
一次ガスの集合点Ａは、上記目標点Ｃ付近に設定される。図示の例では、線材１１Ａ及び１１Ｂの先端より僅かに溶射方向の前方側に寄った位置に集合点Ａが設定されている。この集合点Ａは、目標点Ｃ付近に設定すればよく、線材１１Ａ及び１１Ｂの接触点付近に設定したり、該接触点よりも線材ガイド管５Ａ及び５Ｂの先端側に寄った位置に設定したりしてもよい。
【００４５】
そして、前記４つの一次ガス流路２０８のうち、対角位置にある２つの一次ガス流路は、それぞれの中心線を、線材ガイド管５Ａ及び５Ｂのガイド方向の中心線が配置された平面上に位置させた状態で設けられ、対角位置にある他の２つの一次ガス流路は、上記平面と直交する他の平面上にそれぞれの中心線を位置させた状態で設けられている。線材ガイド管５Ａ及び５Ｂのガイド方向の中心線が配置された平面上に配置された２つの一次ガス流路２０８から流出した一次ガスは線材ガイド管５Ａ及び５Ｂに沿って、両ガイド管に接触しつつ集合点Ａに向けて流れる。また他の２つの一次ガス流路２０８から流出した一次ガスは直接集合点Ａに向けて流れる。
【００４６】
線材ガイド管５Ａ及び５Ｂは、相互に絶縁された状態で設けられていて、両ガイド管５Ａ，５Ｂ間には、給電手段を構成する図示しない電源から電圧が印加されている。
【００４７】
上記２本の線材１１Ａ及び１１Ｂは同種の材料からなっていてもよく、異種の金属、例えばアルミニウムや亜鉛等により形成されていてもよい。
【００４８】
アーク溶射を行うに当っては、ガス溜め室９内に圧縮された一次ガス（空気）を供給して４つの一次ガス流路２０８から集合点Ａに向う一次ガス流Ｇ1 を発生させ、同時にガス溜め室７内に圧縮された二次ガス（空気）を供給して、オリフィス６から集束点Ｂに集束するほぼ円錐状のプロフィルを有する二次ガス流Ｇ2 を発生させる。この二次ガス流Ｇ2 は、２本の線材ガイド管５Ａ，５Ｂの先端から突出した２本の線材１１Ａ，１１Ｂが配置された領域を内包した状態で流れる。また線材ガイド管５Ａ及び５Ｂを通して２本の線材１１Ａ及び１１Ｂを目標点Ｃに向けて送給し、両線材の先端を目標点Ｃ付近で接触させて両線材の先端部間でアークを発生させる。
【００４９】
線材１１Ａ及び１１Ｂの先端部間でアークを発生させると、両線材の先端部付近がアーク熱により溶融する。この溶融した金属に一次ガス流Ｇ1 が吹き付けられるため、溶融金属が霧化して溶融金属の噴霧流が発生する。この噴霧流は一次ガス流Ｇ1 及び線材ガイド管の先端から突出した線材が配置された領域を内包した状態で流れる二次ガス流Ｇ2 とともに溶射方向の前方に噴出させられて、溶射方向の前方に配置された図示しない被溶射物に吹き付けられる。これにより被溶射物の表面に線材１１Ａ及び１１Ｂを構成していた金属からなる被膜が形成される。
【００５０】
上記のように、２本の線材ガイド管５Ａ及び５Ｂが設けられた領域の周囲の複数個所（図示の例では４箇所）から溶射軸線に対して傾斜した方向に沿って集合点Ａに向う複数のビーム状の一次ガス流Ｇ1 を発生させるようにすると、線材のアークにより溶融した部分に集中的にガスを吹き付けることができるため、アークが引き伸ばされるのを防ぎつつ効率よく溶融金属の噴霧流を生じさせることができる。
【００５１】
また４つの一次ガス流路２０８のうち、ガイド管５Ａ及び５Ｂのそれぞれのガイド方向に沿う中心線が配置された平面と同じ平面上に配置された２つの一次ガス流路（図１において上下に示されている２つの一次ガス流路）２０８を通して流れる一次ガスはガイド管５Ａ及び５Ｂに接触しつつ流れるため、両ガイド管がアーク熱により大きく膨脹してそれぞれの内部の線材１１Ａ及び１１Ｂとの間の隙間が大きくなるのを防ぐことができる。したがって、線材１１Ａ及び１１Ｂが線材ガイド管５Ａ及び５Ｂのガイド孔内で揺れてそれぞれの送給方向がぶれるのを防ぐことができ、アークを安定に維持することができる。
【００５２】
上記の例では、４つの一次ガス流路２０８のうちの２つの一次ガス流路を、ガイド管５Ａ及び５Ｂのそれぞれのガイド方向に沿う中心線が配置された平面と同じ平面上に位置させるようにしたが、溶射軸線の回りに９０度間隔で４つの一次ガス流路２０８を設ける場合には、これらの一次ガス流路により生じさせた一次ガス流をアーク点に集中的に吹き付けるために、図３に示したように、対角位置にある各２つの一次ガス流路２０８を、それぞれの中心線を、２本の線材ガイド管の中心線が配置された平面に対して４５度傾いた平面上に位置させた状態で設けるのが好ましい。
【００５３】
このように一次ガス流路を設けると、４つの一次ガス流路２０８を通してそれぞれ流れる一次ガスを２本のガイド管５Ａ及び５Ｂにほとんど妨げられることなく、しかもアークにより加熱されるガイド管の先端部付近に接触させつつアーク発生点に向わせることができるため、溶融した線材の先端部付近に吹き付けるガスの量を多くして溶融金属の霧化を効率よく行わせるとともに、線材ガイド管の温度上昇を抑制して線材の送給を安定化し、アークの安定化を図ることができる。
【００５４】
上記の例では、環状部材２の内周部に設けた孔により一次ガス流路２０８を形成したが、図４に示すように、先端部が集合点Ａに指向し、後端部がガス溜め室９に開口したパイプを環状部材２の孔部２００の内周に取り付けることにより、一次ガス流路２０８を形成するようにしてもよい。
【００５５】
また上記の各例では、第１及び第２の線材ガイド管５Ａ及び５Ｂが配置された領域の周囲の領域から溶射軸線Ｏ−Ｏに対して傾斜した方向に沿って一次ガス流を生じさせるように一次ガス流路２０８を設けたが、図５に示すように、線材ガイド管５Ａ及び５Ｂに沿って一次ガス流を生じさせるように一次ガス流路２０８を形成してもよい。図５に示した例では、主部２０１と突出部２０２とを有して内側に孔部２００が形成された環状部材２と、周壁部の内周に雌ネジ部３０３を有して、該雌ネジ部が環状部材２の外周に形成された雄ネジ部２０５に螺合されて環状部材２に取り付けられた筒体３とにより溶射ヘッド本体が構成されている。この溶射ヘッド本体と、環状部材２の内側の孔部２００内に挿入されて、先端が孔部２００の開口部２００ａ付近で終端させられた第１及び第２の線材ガイド管５Ａ及び５Ｂと、第１及び第２の線材ガイド管５Ａ及び５Ｂのそれぞれの先端部付近を同軸的に取り囲むように取り付けられた第１及び第２の套管１２Ａ及び１２Ｂとにより溶射ヘッド１´が構成されている。
【００５６】
套管１２Ａ及び１２Ｂと線材ガイド管５Ａ及び５Ｂとの間には、それぞれの長手方向に沿って延びて先端が目標点Ｃ側に開口した一次ガス流路２０８Ａ及び２０８Ｂと、一次ガス流路２０８Ａ及び２０８Ｂの後端部に連通するガス溜め室１３Ａ及び１３Ｂとが形成されている。ガス溜め室１３Ａ及び１３Ｂには図示しない一次ガス供給手段から配管１４を通して圧縮された一次ガスが供給されている。一次ガス流路２０８Ａ及び２０８Ｂは、線材ガイド管５Ａ及び５Ｂの外周を同軸的に取り囲むように設けられていて、ガス溜め室１３Ａ及び１３Ｂ内に圧縮された一次ガスが供給されたときに、一次ガス流路２０８Ａ及び２０８Ｂからそれぞれ線材１１Ａ及び１１Ｂの外面に沿って目標点Ｃ側に流れる一次ガス流Ｇ1 が生じるようになっている。
【００５７】
筒体３の端部壁３０２の中央部には、環状部材２の突出部２０２の外周に形成されたガス案内面２０４と同じ側に傾斜して、ガス案内面２０４を一定の間隙を介して取り囲む内周面を有する開口部３０４が形成され、この開口部３０４の内周面とガス案内面２０２との間に形成された隙間により、環状部材２と中心軸線を共有し、かつ溶射軸線Ｏ−Ｏ上に設定された集束点Ｂに集束する方向に沿うように傾斜した状態で孔部２００を連続的に取り囲むオリフィス６が形成されている。
【００５８】
図示の例では、第１及び第２の套管１２Ａ及び１２Ｂの先端部を先細りの形状とすることにより、一次ガス流路２０８Ａ及び２０８Ｂからそれぞれ流出する一次ガス流Ｇ1 の径を絞って、該一次ガス流を線材１１Ａ及び１１Ｂの外周に沿わせるようにしている。
【００５９】
図５に示すように構成した場合には、一次ガス流路２０８Ａ及び２０８Ｂの先端から流出した一次ガス流Ｇ1 が線材ガイド管５Ａ及び５Ｂの先端から突出した線材１１Ａ及び１１Ｂの外周に沿って流れ、これらの一次ガス流が線材１１Ａ及び１１Ｂの先端の溶融部分に吹き付けられる。
【００６０】
図５に示したように構成すると、一次ガス流は、各線材ガイド管の先端から線材に沿って流れて、線材の先端の溶融部分に吹き付けられるため、溶融金属の霧化を効率よく行わせることができる。また一次ガス流Ｇ1 を線材ガイド管５Ａ及び５Ｂに直接接触させながら流すことができるため、線材ガイド管５Ａ及び５Ｂがアーク熱により加熱されて大きく熱膨張するのを防ぎ、アークの安定化を図ることができる。
【００６１】
上記の例では、環状部材２の内側の孔部２００の開口部を連続的に取り囲むようにオリフィス６を形成したが、図６に示したように、オリフィス６を環状部材２の内側の孔部２００の開口部を断続的に取り囲む形状とするように、該オリフィス６を複数の円弧状の孔６ａ，６ａ，…により形成するようにしてもよい。
【００６２】
【発明の効果】
以上のように、本発明において、２本の線材ガイド管が設けられた領域の周囲の複数個所から溶射軸線に対して傾斜した方向に沿って集合点に向う複数の一次ガス流を発生させるようにした場合には、溶射軸線に対して傾斜した方向から線材のアークにより溶融した部分に集中的にガスを吹き付けることができるため、アークが引き伸ばされるのを防いでアークを安定に維持しつつ効率よく溶融金属の噴霧流を生じさせることができる。また一次ガス流の一部を線材ガイド管に接触させて該線材ガイド管を冷却することができるため、アーク熱による線材ガイド管の膨脹を抑制して、該線材ガイド管によりガイドされる線材に揺れが生じるのを防ぎ、アークの安定化を図ることができる。
【００６３】
更に上記の方法によれば、線材の先端の溶融した部分に一次ガス流を十分な流速を持って吹き付けて、霧化した溶融金属を溶射方向の前方に送り出すことができるため、霧化した溶融金属が線材ガイド管の先端部付近に滞留するのを防ぐことができる。したがって、線材ガイド管の先端部に金属が付着するのを防ぐことができ、線材ガイド管の先端部に付着した金属により溶射用線材のスムーズな供給が妨げられたり、一次ガスの流れが乱されたりするのを防ぐことができる。
【００６４】
また本発明において、２本の線材ガイド管の長手方向に沿って一次ガス流を生じさせるようにした場合には、該一次ガス流を線材ガイド管から突出した線材の外面に沿って線材の先端の溶融部分に吹き付けることができるため、２本の線材の先端部間で発生したアークを引き伸ばすことなく、線材の溶融部分に一次ガス流を集中的に吹き付けて、溶融金属の霧化を効率よく行わせることができる。またこの場合、一次ガス流を線材ガイド管に直接接触させて該線材ガイド管を冷却することができるため、線材ガイド管の冷却効果を高めることができる。
【図面の簡単な説明】
【図１】本発明に係わるアーク溶射装置で用いる溶射ヘッドの要部の構造を示す縦断面図である。
【図２】図１の溶射ヘッドの正面図である。
【図３】図１の溶射ヘッドにおける一次ガス流路の配列の仕方の変形例を示した断面図である。
【図４】本発明に係わるアーク溶射装置で用いる溶射ヘッドの変形例を示した縦断面図である。
【図５】本発明に係わるアーク溶射装置で用いる溶射ヘッドの他の変形例を示した縦断面図である。
【図６】本発明に係わるアーク溶射装置で用いる溶射ヘッドの更に他の変形例を示した正面図である。
【符号の説明】
１，１´…溶射ヘッド、２…環状部材、２００…孔部、２０８，２０８A ，２０８B …一次ガス流路、３，４…筒体、５Ａ，５Ｂ…線材ガイド管、６…オリフィス、１１Ａ，１１Ｂ…溶射用線材。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an arc spraying method and an arc spraying apparatus for forming a metal film on the surface of a sprayed object by atomizing a metal melted by an arc and spraying the metal on the sprayed object.
[0002]
[Prior art]
In a component of equipment installed outdoors, such as harbor facilities, bridges, steel towers, etc., a rust-preventing film or a corrosion-resistant film is often formed on the surface.
[0003]
As one of methods for forming a corrosion-resistant film on the surface of a material or product, an arc spraying method is known. The arc spraying method includes two wire guide tubes whose tips are directed to a target point set on an axis along the spraying direction (hereinafter referred to as a spraying axis), and means for supplying gas in the vicinity of the target point. The two thermal spraying heads are used to guide the two thermal spraying wires with the two wire guide pipes and feed them toward the target point. The two thermal spraying wires protrude from the tips of the two wire guide tubes. Touch the tip of near the target point. Then, by applying a voltage between both wires, an arc is generated between the tips of both wires, the tips of both wires are melted, and a gas flow is blown to the tips of the melted wires to melt The molten wire is atomized to form a molten metal spray stream. This spray flow is sprayed on the sprayed object disposed in front of the spraying direction to form a metal film on the surface of the sprayed object. When the two wires made of different metals are used, an alloy film of different metals can be formed.
[0004]
In the case of forming a coating for rust prevention or a coating having corrosion resistance, for example, a zinc wire and an aluminum wire are used as the two wires.
[0005]
In the conventional arc spraying method, the primary gas flow that flows along the spray axis is generated toward the tip of the wire melted by the arc, and the region where the wire protruding from the tip of the wire guide tube is disposed A secondary gas flow that flows so as to converge toward a converging point on the spray axis set from a position before the target point to a position further forward than the target point in a state including the primary gas flow is generated. After the molten metal is sprayed on the tip of the wire, a molten metal spray flow is formed, and then the spray flow is focused by a secondary gas flow flowing so as to wrap from the outside, and jetted forward in the spraying direction.
[0006]
[Problems to be solved by the invention]
In the conventional arc spraying method, the primary gas flow is made to flow along the spray axis. Therefore, when the air flow rate of the primary gas flow is increased and the wind speed is increased, the arc of the arc generated between the two wire tips. There was a problem that the length became long and the arc became unstable.
[0007]
In particular, when thermal spraying is performed using a wire made of a metal having a low melting point such as zinc, a low voltage is applied between the wires to generate an arc. In this case, a gas flow strong against the arc along the spray axis. The length of the arc becomes longer and the arc breaks easily.
[0008]
In addition, as disclosed in Japanese Patent Application Laid-Open No. 11-279743, there is also a type in which a primary gas flow is caused to flow through the entire space (hole) in the head in which two wire guide tubes are arranged. In this case, since the two wire rods are arranged at the center of the primary gas flow, the primary gas flow cannot be intensively sprayed on the melted portion at the tip of the two wire rods. There is a problem that it is difficult to efficiently atomize the molten metal.
[0009]
In addition, in the conventional arc spraying method, it is difficult to blow a primary gas having a sufficient flow rate to the molten portion at the tip of the two wires, so that the atomized metal floats near the tip of the two wires. However, when spraying for a long time on the tip of the wire guide, the metal attached to the tip of the wire guide hinders smooth supply of the wire or disturbs the gas flow.
[0010]
An object of the present invention is to propose an arc spraying method in which the arc is stably maintained to stabilize the operation and the molten metal can be efficiently atomized.
[0011]
Another object of the present invention is to provide an arc spraying method capable of preventing molten metal from adhering to the tip of a wire guide and preventing the smooth supply of the wire or disturbing the gas flow. There is.
[0012]
Still another object of the present invention is to provide an arc spraying apparatus for performing the above-described spraying method.
[0013]
[Means for Solving the Problems]
In the arc spraying method according to the present invention, the two wire rods for spraying are fed toward the target point while being guided by the two wire rod guide pipes whose ends are directed to the target point set on the spray axis. Then, the tips of the two thermal spray wires protruding from the tips of the two wire guide pipes are brought into contact with each other near the target point, and a voltage is applied between the two wires to cause an arc between the tips of the two wires. Is generated. Also, a set point of primary gas flow is set near the target point, and a plurality of points that are directed to the set point along a direction inclined with respect to the spray axis from a plurality of locations around the region where the two wire guide pipes are provided. The beam-like primary gas flow is generated, and the position where the wire rod protruding from the two wire rod guide pipes is included is set from a position before the target point to a position further ahead of the target point. A secondary gas flow that flows so as to converge toward a focusing point on the spray axis is generated. The primary gas flow Concentrated on the part melted by the arc at the tip of the two wires Spraying is performed by forming a spray flow of molten metal by spraying and spraying the spray flow together with the secondary gas flow toward a sprayed object disposed in front of the spraying direction.
[0014]
As described above, a plurality of beam-like primary gas flows are generated from a plurality of locations around the region where the two wire guide pipes are provided along the direction inclined with respect to the spray axis along the direction toward the assembly point. Then, gas can be sprayed intensively on the part melted by the arc of the wire, so that the arc can be prevented from being stretched, and the molten metal spray can be efficiently generated while maintaining the arc stably.
[0015]
In a preferred aspect of the present invention, an annular member having an inner hole having an opening at the front side in the spraying direction provided so that the center axis coincides with the axis along the spraying direction, and the center axis coincide with the spraying axis. In addition, an orifice that is provided so as to continuously or intermittently surround the hole in a state of being inclined so as to be converged at a converging point set on the spraying axis, and whose tip is opened forward in the spraying direction. A head main body, and a hole penetrating through the hole of the annular member so that the tip ends in the vicinity of the opening position of the hole, and is positioned between the opening position of the hole and the focusing point. In order to generate an arc between a thermal spraying head including two wire rod guide tubes configured to guide a thermal spray wire toward a target point set on the spray axis and between the tips of the two wire rods Power supply means for supplying power between both wires. Performing the arc spraying Te.
[0016]
Also in this case, a set point of the primary gas flow is set in the vicinity of the target point, and the spray axis is formed from a plurality of locations outside the region where the two wire guide tubes are arranged in the hole of the head body. On the other hand, a plurality of beam-like primary gas flows directed toward the collecting point along the inclined flow path are generated, and a secondary gas flow that is ejected from the orifice and flows toward the focusing point is generated. And the primary gas flow Concentrated on the part melted by the arc at the tip of the two wires Spraying is performed by generating a spray flow of molten metal by spraying, and spraying the spray flow together with the secondary gas flow toward a sprayed object disposed in front of the spraying direction.
[0017]
When performing the above-described arc spraying method, it is preferable that at least a part of the plurality of primary gas flows is brought into contact with the vicinity of the tip portions of the two guide tubes.
[0018]
In this way, when at least a part of the primary gas flow is brought into contact with the wire guide tube, the wire guide tube is cooled to suppress the expansion of the wire guide tube due to arc heat, and between the wire guide tube and the wire. Since the change in the gap can be reduced, it is possible to stabilize the arc by reducing the fluctuation of the wire fed toward the target point through the guide tube.
[0019]
Further, when the beam-like primary gas flow is generated as described above and the primary gas flow is sprayed on the molten portion at the tip of the two wires, the flow rate of the gas sprayed on the molten portion of the wire can be increased. Therefore, the atomized molten metal can be moved forward without being retained in the vicinity of the tip of the wire, and sent out on the secondary gas flow. Therefore, there is no risk of molten metal adhering to the tip of the wire guide, the metal adhering to the tip of the wire guide hinders smooth supply of the wire, and the gas flow near the tip of the wire guide Can be prevented from being disturbed.
[0020]
In the present invention, a primary gas channel formed along the longitudinal direction of each of the two wire guide tubes and having a tip opened toward the target point is provided. The primary gas flow respectively flowing out from the primary gas flow paths extending in the respective longitudinal directions is blown along the two wires to the molten portion near the tips of both wires, thereby generating a molten metal spray flow. Good.
[0021]
Also in this case, it is possible to blast the molten metal at the tip of the wire rod intensively while preventing the arc generated between the tip portions of the two wire rods from being stretched. Can be generated.
[0022]
In addition, since the wire guide tube can be cooled by the primary gas flow when configured as described above, expansion of the wire guide tube due to arc heat is suppressed, and the change in the gap between the wire guide tube and the wire is reduced. In addition, it is possible to stabilize the arc by reducing the shaking of the wire fed through the guide tube.
[0023]
Furthermore, even when configured as described above, since the primary gas having a sufficiently large flow velocity can be intensively blown to the molten portion of the wire, and the atomized molten metal can be moved forward, the tip of the wire guide It is possible to prevent the molten metal from adhering to the vicinity.
[0024]
When the molten metal is atomized by spraying a primary gas flow on the molten wire, the optimum value of the flow rate of the primary gas flow sprayed on the molten metal differs depending on the material, wire diameter, etc. of the thermal spray wire. Therefore, the flow rate of the primary gas flow is preferably set to an appropriate value according to the type of the wire for thermal spraying.
[0025]
An arc spraying apparatus according to the present invention is provided with an annular member that is provided so that a central axis coincides with a spraying axis and has a hole that has a tip opened forward in the spraying direction, and the central axis coincides with the spraying axis. And an orifice that is provided so as to continuously or intermittently surround the hole in a state of being inclined along the direction of focusing at a focusing point set on the spraying axis, and whose tip is opened forward in the spraying direction; A head body provided with a gas reservoir chamber communicated with a rear end portion of the orifice, and a front end penetrating through a hole portion of the annular member and ending near the opening position of the hole portion; Two wire rod guide tubes configured to guide the thermal spray wire toward a target point set on the thermal spray axis in a state of being positioned between the opening position of the hole and the focusing point; Front side of spraying direction inside annular member A thermal spraying head provided with a primary gas flow forming means for generating a flowing primary gas flow, and a secondary gas supply means for supplying a secondary gas compressed into a gas reservoir chamber in order to eject the secondary gas from the orifice; In order to generate an arc between the tips of two wire rods, a power feeding means for feeding power between both wire rods is provided.
[0026]
In the present invention, the set point of the primary gas flow is set on the spray axis in a state of being positioned between the vicinity of the tips of the two wires and the vicinity of the tip of the wire guide tube. The primary gas flow forming means is formed at a set point along a direction inclined with respect to the spray axis from a plurality of locations outside the region where the two wire guide tubes are disposed in the hole inside the annular member. It flows in the direction and is sprayed intensively on the melted part by the arc at the tip of the two wires. In order to generate a plurality of beam-like primary gas flows, it is constituted by a plurality of primary gas flow paths which are provided in an inclined state with respect to the spray axis and whose front ends are directed to the assembly point in the hole.
[0027]
At least some of the primary gas flow paths among the plurality of primary gas flow paths are provided so as to generate a primary gas flow that flows in contact with the vicinity of the tip portions of the two guide tubes. In a preferred embodiment of the present invention, the two wire rod guide tubes are provided in a state where the center lines along the respective guide directions are positioned on a plane including the center axis of the annular member. In addition, four primary gas flow paths are provided at intervals of 90 degrees around the center axis of the annular member, and two of the four primary gas flow paths are divided into two central lines. It is provided in a state of being positioned on a plane on which the center line of the wire guide tube is arranged.
[0028]
If comprised as mentioned above, the primary gas flow which flows into contact with each wire rod guide pipe | tube by the two primary gas flow paths which located the center line on the plane by which the center axis line of two wire rod guide pipe | tubes is arrange | positioned. As a result, each wire guide tube can be cooled, so that the thermal expansion of each wire guide tube can be suppressed to reduce the swing of the wire and stabilize the arc.
[0029]
As described above, four primary gas flow paths are provided at intervals of 90 degrees around the spray axis, and the primary gas flow generated by these primary gas flow paths is intensively blown to the arc point. Each of the two primary gas flow paths at an angular position is provided with its center line positioned on a plane inclined by 45 degrees with respect to the plane on which the center lines of the two wire rod guide tubes are arranged. Is preferred.
[0030]
When the primary gas flow paths are provided in this way, the primary gas flowing through the four primary gas flow paths is brought into contact with the vicinity of the tip of the guide tube heated by the arc with almost no obstruction by the two guide tubes. Since it can be directed toward the arc point, the amount of gas blown near the tip of the wire is increased to efficiently atomize the molten metal, and the temperature rise of the wire guide tube is suppressed to suppress the temperature rise of the wire. The feeding can be stabilized and the arc can be kept stable.
[0031]
In another preferred embodiment of the present invention, a primary gas flow path formed along the longitudinal direction of two wire guide tubes and having a tip opened to the target point side, and the longitudinal direction of each wire guide tube And a primary gas supply means for supplying the compressed primary gas to the primary gas passage along the line.
[0032]
If comprised in this way, since a primary gas flow will flow along the wire from the front-end | tip of each wire guide pipe, and will be intensively sprayed on the fusion | melting part of the front-end | tip of two wire rods, atomization of molten metal will be performed efficiently. Can be done.
[0033]
When the primary gas passage is formed along the longitudinal direction of each wire guide tube as described above, the primary gas passage is coaxial with the wire guided by each wire guide tube in order to stabilize the gas flow. It is preferable to form so that it may surround.
[0034]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. 1 and 2 show a preferred configuration example of a thermal spraying head used in the arc thermal spraying method according to the present invention. FIG. 1 is a longitudinal sectional view of the thermal spraying head, and FIG. 2 is a front view thereof. The thermal spraying head 1 shown in FIG.1 and FIG.2 is provided with the annular member 2 which is provided so that a center axis may coincide with the thermal spraying axis OO, and has a hole portion 200 having a tip opened forward in the thermal spraying direction. The first and second cylinders 3 and 4 attached to the annular member 2 and the first and second wire rod guide tubes 5A and 5B are provided.
[0035]
The annular member 2 includes an annular main portion 201 having a cylindrical outer peripheral surface whose central axis coincides with the spray axis OO, and a flange protruding from the inner peripheral side of the main portion 201 to one side in the axial direction. The main part 201 and the inner peripheral surface 203 of the projecting part 202 are continuous conical cones whose central axis coincides with the spray axis OO line. It is a surface. The inner peripheral surface 203 is provided so as to incline in a direction in which the diameter gradually decreases toward the front side in the spraying direction, and the space inside the inner peripheral surface 203 is the hole portion 200. Further, the outer peripheral surface of the projecting portion 202 of the annular member 2 is a frustoconical gas guide surface 204 whose center axis coincides with the spray axis OO. A first male screw portion 205 is provided on the outer periphery of the portion of the annular member 201 near the other end in the axial direction, and a second male screw portion 206 is provided on the outer periphery of the portion of the annular member 201 near the other end in the axial direction. Are formed, and a protrusion 207 is provided between the first male screw portion 205 and the second male screw portion 206.
[0036]
In the portion near the inner periphery of the main portion 201 of the annular member 2, a primary formed of a hole inclined on the same side as the inner peripheral surface 203 and with a larger inclination angle than the inner peripheral surface 203 with respect to the spray axis OO. Four gas flow paths 208 are formed at intervals of 90 degrees in the circumferential direction (4 equally around the spray axis). Each primary gas flow path 208 has an opening 208a on the front end side directed to an aggregation point A of the primary gas flow G1 set as described later through an opening 200a on the front end side of the hole 200, and a rear end portion. The opening 208b on the side is provided so as to open to the end surface on the other end side in the axial direction of the annular member 2.
[0037]
The first cylinder 3 is made of a metal cylinder having a peripheral wall portion 301 and an end wall 302 formed on one end side in the axial direction of the peripheral wall portion, and is formed on the inner periphery of the peripheral wall portion 301. The female screw portion 303 thus formed is screwed into the first male screw portion 205 on the outer periphery of the annular member 2 and fixed to the annular member 2. The central portion of the end wall 302 of the first cylindrical body 3 is inclined to the same side as the gas guide surface 204 formed on the outer periphery of the projecting portion 202 of the annular member 2 so that the gas guide surface 204 has a certain gap. An opening 304 having an inner peripheral surface that surrounds the annular member 2 is shared by the gap formed between the inner peripheral surface of the opening 304 and the gas guide surface 202, and An orifice 6 is formed so as to continuously surround the hole 200 in a state of being inclined along the direction of focusing at the focusing point B set on the spray axis OO.
[0038]
An annular gas reservoir chamber 7 surrounding the gas guide surface 204 is formed between the first cylinder 3 and the annular member 2, and the gas reservoir chamber 7 is communicated with the rear end portion of the orifice 6. A secondary gas (usually compressed) into the gas reservoir chamber 7 through a secondary gas flow supply pipe 8 connected to a hole penetrating the peripheral wall of the first cylinder 3 from a secondary gas supply means (not shown) such as a compressor. Is supplied), and a secondary gas flow G2 from the gas reservoir chamber 7 to the converging point B through the orifice 6 is generated.
[0039]
The second cylindrical body 4 includes a cylindrical outer wall 401, a cylindrical inner wall 402 having a shorter axial dimension than the outer wall 401, and one axial end of these walls. A female threaded portion 404 formed on the inner periphery of the outer wall 401 and screwed into a second male threaded portion 206 formed on the outer periphery of the annular member 2. The other end in the axial direction of the inner wall 402 is brought into contact with the inner peripheral portion of the end face on the other end side in the axial direction of the annular member 2 via an airtight holding means such as packing. An annular gas reservoir chamber 9 surrounding the spray axis OO is formed between the second cylinder 4 and the annular member 2, and each primary gas flow path 208 provided in the annular member 2 is formed in the gas reservoir chamber 9. It is communicated inside. A compressed primary gas (usually air) is supplied into the gas reservoir chamber 9 through a primary gas supply pipe 10 connected to a hole penetrating the outer wall 401 of the second cylinder 4. A beam-like primary gas flow G 1 is generated from the chamber 9 through each primary gas flow path 208 toward the collecting point A. In this example, the gas reservoir chamber 9, the primary gas flow path 208, and the primary gas supply means (not shown) for supplying the compressed primary gas to the gas reservoir chamber 9, the spraying direction inside the annular member 2. A primary gas flow forming means for generating a primary gas flow G1 flowing forward is provided. In order to appropriately change the flow rate of the primary gas flow, the primary gas supply means is configured to change the pressure of the primary gas supplied to the gas reservoir chamber 9.
[0040]
The annular member 2 and the first and second cylinders 3 and 4 constitute a head body having an orifice 6 and a gas reservoir chamber 7 communicating with the orifice.
[0041]
The first wire rod guide tube 5A and the second wire rod guide tube 5B include a straight tube portion 501 extending in the hole 200 of the annular member 2 parallel to the spray axis OO, and a spray axis from the tip of the straight tube portion. The guide hole h is made of a metal tube having a bent portion 502 bent to the OO side, and guides the thermal spraying wires 11A and 11B in a state of penetrating the inner axial core portion in the longitudinal direction. Is formed.
[0042]
The first and second wire rod guide pipes 5A and 5B have center lines along the respective guide directions (center axes along the longitudinal direction of the wire rods 11A and 11B to be guided) on a plane including the spray axis OO. And the ends of the wire rods 11A and 11B that are guided by the tips of the wire members 11A and 11B are respectively positioned at the opening position P of the hole portion 200 of the annular member 2 and the focusing point. B is provided so as to be directed to a target point C set on the spray axis OO.
[0043]
The thermal spraying wires 11A and 11B are fed by a feeding mechanism composed of a pressing roller and a feeding roller and fed into the wire guide tubes 5A and 5B, and are guided to the target point C while being guided by these guide tubes 5A and 5B. The leading ends are in contact with each other in the vicinity of the target point C.
[0044]
The primary gas gathering point A is set near the target point C. In the illustrated example, the set point A is set at a position slightly closer to the front side in the spraying direction than the tips of the wires 11A and 11B. This set point A may be set in the vicinity of the target point C, set near the contact point of the wire rods 11A and 11B, or set at a position closer to the tip side of the wire rod guide pipes 5A and 5B than the contact point. Or you may.
[0045]
Of the four primary gas flow paths 208, the two primary gas flow paths at diagonal positions are on the plane on which the center lines are arranged in the guide direction of the wire guide tubes 5A and 5B. The other two primary gas flow paths at the diagonal positions are provided with their center lines positioned on other planes orthogonal to the plane. The primary gas flowing out from the two primary gas flow paths 208 arranged on the plane in which the center line in the guide direction of the wire rod guide pipes 5A and 5B is arranged contacts both the guide pipes along the wire rod guide pipes 5A and 5B. However, it flows toward the meeting point A. Further, the primary gas flowing out from the other two primary gas flow paths 208 flows directly toward the collecting point A.
[0046]
The wire guide tubes 5A and 5B are provided in a state of being insulated from each other, and a voltage is applied between the guide tubes 5A and 5B from a power source (not shown) that constitutes a power feeding unit.
[0047]
The two wires 11A and 11B may be made of the same kind of material, and may be made of different metals such as aluminum and zinc.
[0048]
In performing the arc spraying, the primary gas (air) compressed in the gas reservoir chamber 9 is supplied to generate the primary gas flow G1 from the four primary gas flow paths 208 toward the collecting point A, and at the same time the gas is sprayed. A compressed secondary gas (air) is supplied into the reservoir chamber 7 to generate a secondary gas flow G2 having a substantially conical profile that converges from the orifice 6 to the convergence point B. The secondary gas flow G2 flows in a state of including a region where the two wire rods 11A and 11B protruding from the tips of the two wire rod guide tubes 5A and 5B are disposed. Further, the two wire rods 11A and 11B are fed toward the target point C through the wire rod guide pipes 5A and 5B, and the tips of both wires are brought into contact with each other in the vicinity of the target point C to generate an arc between the tip portions of the two wire rods. .
[0049]
When an arc is generated between the tips of the wires 11A and 11B, the vicinity of the tips of both wires is melted by the arc heat. Since the primary gas flow G1 is sprayed on the molten metal, the molten metal atomizes and a molten metal spray flow is generated. This spray flow is jetted forward in the spraying direction together with the primary gas flow G1 and the secondary gas flow G2 flowing in a state including the region where the wire projecting from the tip of the wire guide tube is disposed, and forward in the spraying direction. It sprays on the sprayed object which is arranged and which is not illustrated. Thereby, the film which consists of the metal which comprised the wire 11A and 11B on the surface of a to-be-sprayed object is formed.
[0050]
As described above, the set points along the direction inclined with respect to the spray axis from a plurality of locations (four locations in the illustrated example) around the region where the two wire guide tubes 5A and 5B are provided. A By generating a plurality of beam-like primary gas flows G1 directed toward the gas, it is possible to blast the gas intensively to the melted portion by the arc of the wire, so that the molten metal can be efficiently formed while preventing the arc from being stretched. A spray flow can be generated.
[0051]
Further, of the four primary gas flow paths 208, two primary gas flow paths (up and down in FIG. 1) arranged on the same plane as the plane where the center lines along the guide directions of the guide tubes 5A and 5B are arranged. Since the primary gas flowing through the two primary gas flow paths (208) shown in FIG. 208 is in contact with the guide tubes 5A and 5B, both guide tubes are greatly expanded by the arc heat, and the inner wires 11A and 11B It is possible to prevent the gap between them from increasing. Therefore, the wire rods 11A and 11B can be prevented from shaking in the guide holes of the wire rod guide pipes 5A and 5B and the respective feeding directions are shaken, and the arc can be stably maintained.
[0052]
In the above example, two primary gas flow paths out of the four primary gas flow paths 208 are positioned on the same plane as the plane where the center lines along the guide directions of the guide tubes 5A and 5B are arranged. However, when four primary gas flow paths 208 are provided at intervals of 90 degrees around the spray axis, in order to intensively blow the primary gas flow generated by these primary gas flow paths to the arc point, As shown in FIG. 3, each of the two primary gas flow paths 208 at the diagonal positions is inclined at 45 degrees with respect to the plane on which the center lines of the two wire rod guide pipes are arranged. It is preferably provided in a state of being positioned on a plane.
[0053]
When the primary gas flow paths are provided in this way, the distal ends of the guide tubes heated by the arc are hardly obstructed by the two guide tubes 5A and 5B, respectively, through the four primary gas flow channels 208. Since it can be directed to the arc generation point while being in contact with the vicinity, the amount of gas blown near the tip of the molten wire is increased to efficiently atomize the molten metal, and the temperature of the wire guide tube It is possible to stabilize the arc by suppressing the rise and stabilizing the feeding of the wire.
[0054]
In the above example, the primary gas flow path 208 is formed by the hole provided in the inner peripheral portion of the annular member 2, but as shown in FIG. 4, the front end portion is directed to the gathering point A and the rear end portion is the gas reservoir. The primary gas flow path 208 may be formed by attaching a pipe opened to the chamber 9 to the inner periphery of the hole 200 of the annular member 2.
[0055]
In each of the above examples, the primary gas flow is generated along the direction inclined with respect to the spray axis OO from the region around the region where the first and second wire guide tubes 5A and 5B are disposed. Although the primary gas flow path 208 is provided in FIG. 5, the primary gas flow path 208 may be formed so as to generate a primary gas flow along the wire guide tubes 5A and 5B as shown in FIG. In the example shown in FIG. 5, the annular member 2 having the main portion 201 and the protruding portion 202 and having the hole portion 200 formed therein, and the female screw portion 303 on the inner periphery of the peripheral wall portion, The thermal spray head main body is composed of the cylindrical body 3 attached to the annular member 2 by screwing the female thread portion into the male screw portion 205 formed on the outer periphery of the annular member 2. The thermal spray head main body, the first and second wire guide tubes 5A and 5B inserted into the hole 200 inside the annular member 2 and terminated at the vicinity of the opening 200a of the hole 200, A thermal spraying head 1 'is constituted by the first and second sleeves 12A and 12B attached so as to coaxially surround the vicinity of the respective distal end portions of the first and second wire rod guide tubes 5A and 5B. .
[0056]
Between the cannula 12A and 12B and the wire guide pipes 5A and 5B, primary gas flow paths 208A and 208B extending along the respective longitudinal directions and having their tips opened to the target point C side, and the primary gas flow path 208A And gas reservoir chambers 13A and 13B communicating with the rear ends of 208B. Compressed primary gas is supplied to the gas reservoir chambers 13A and 13B through a pipe 14 from a primary gas supply means (not shown). The primary gas flow paths 208A and 208B are provided so as to coaxially surround the outer periphery of the wire rod guide pipes 5A and 5B, and when the compressed primary gas is supplied into the gas reservoir chambers 13A and 13B, A primary gas flow G1 flowing from the gas flow paths 208A and 208B toward the target point C along the outer surfaces of the wires 11A and 11B is generated.
[0057]
The central portion of the end wall 302 of the cylindrical body 3 is inclined to the same side as the gas guide surface 204 formed on the outer periphery of the projecting portion 202 of the annular member 2 so that the gas guide surface 204 is interposed through a certain gap. An opening 304 having an inner peripheral surface that surrounds is formed, and the gap formed between the inner peripheral surface of the opening 304 and the gas guide surface 202 shares the central axis with the annular member 2 and is the spray axis O. An orifice 6 that continuously surrounds the hole 200 is formed in a state of being inclined along the direction of focusing at the focusing point B set on −O.
[0058]
In the example shown in the drawing, the diameters of the primary gas flow G1 flowing out from the primary gas flow paths 208A and 208B are reduced by making the tip portions of the first and second sleeves 12A and 12B taper, respectively. The primary gas flow is made to follow the outer circumferences of the wires 11A and 11B.
[0059]
When configured as shown in FIG. 5, the primary gas flow G1 flowing out from the tips of the primary gas flow paths 208A and 208B flows along the outer periphery of the wires 11A and 11B protruding from the tips of the wire guide tubes 5A and 5B. These primary gas flows are sprayed on the melted portions at the tips of the wires 11A and 11B.
[0060]
If comprised as shown in FIG. 5, since a primary gas flow will flow along a wire from the front-end | tip of each wire guide pipe, and will be sprayed on the fusion | melting part of the front-end | tip of a wire, it will perform atomization of molten metal efficiently. be able to. Further, since the primary gas flow G1 can be made to flow while being in direct contact with the wire guide tubes 5A and 5B, the wire guide tubes 5A and 5B are prevented from being heated by the arc heat and greatly expanded, thereby stabilizing the arc. be able to.
[0061]
In the above example, the orifice 6 is formed so as to continuously surround the opening of the hole 200 inside the annular member 2, but the orifice 6 is formed in the hole inside the annular member 2 as shown in FIG. The orifice 6 may be formed by a plurality of arc-shaped holes 6a, 6a,... So as to intermittently surround the 200 openings.
[0062]
【The invention's effect】
As described above, in the present invention, a plurality of primary gas flows are generated from a plurality of locations around the area where the two wire guide pipes are provided toward a set point along a direction inclined with respect to the spray axis. In this case, the gas can be intensively blown from the direction inclined with respect to the spray axis to the melted portion of the wire by the arc, so that the arc is prevented from being stretched and the arc is maintained stably. It is possible to generate a molten metal spray flow well. Further, since the wire guide tube can be cooled by bringing a part of the primary gas flow into contact with the wire guide tube, the wire guide pipe is guided by the wire guide tube by suppressing the expansion of the wire guide tube due to arc heat. It is possible to prevent the occurrence of shaking and stabilize the arc.
[0063]
Furthermore, according to the above method, the atomized molten metal can be sent forward in the spraying direction by spraying the primary gas flow with a sufficient flow velocity to the molten portion at the tip of the wire, so that the atomized melt It is possible to prevent the metal from staying near the tip of the wire guide tube. Therefore, it is possible to prevent the metal from adhering to the tip of the wire guide tube, and the metal adhering to the tip of the wire guide tube hinders the smooth supply of the thermal spraying wire or disturbs the flow of the primary gas. Can be prevented.
[0064]
Further, in the present invention, when the primary gas flow is generated along the longitudinal direction of the two wire guide tubes, the tip of the wire along the outer surface of the wire protruding from the wire guide tube. Since the primary gas flow is intensively blown to the molten part of the wire without stretching the arc generated between the two wire rod tips, the molten metal can be atomized efficiently. Can be done. Further, in this case, since the primary gas flow can be directly contacted with the wire guide tube to cool the wire guide tube, the cooling effect of the wire guide tube can be enhanced.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a structure of a main part of a thermal spraying head used in an arc spraying apparatus according to the present invention.
FIG. 2 is a front view of the thermal spraying head of FIG.
3 is a cross-sectional view showing a modification of the arrangement of primary gas flow paths in the thermal spraying head of FIG. 1. FIG.
FIG. 4 is a longitudinal sectional view showing a modification of the thermal spraying head used in the arc thermal spraying apparatus according to the present invention.
FIG. 5 is a longitudinal sectional view showing another modified example of the thermal spraying head used in the arc thermal spraying apparatus according to the present invention.
FIG. 6 is a front view showing still another modified example of the thermal spraying head used in the arc thermal spraying apparatus according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1,1 '... Spraying head, 2 ... Ring member, 200 ... Hole, 208, 208A, 208B ... Primary gas flow path, 3, 4 ... Cylindrical body, 5A, 5B ... Wire guide pipe, 6 ... Orifice, 11A, 11B: Thermal spray wire.

Claims

Two wire rods for thermal spraying are fed toward the target point while being guided by two wire rod guide tubes each having a tip directed to a target point set on an axis line (hereinafter referred to as a spray axis) along the spraying direction. The two wire rods for thermal spraying projecting from the tip ends of the two wire rod guide pipes are brought into contact with each other in the vicinity of the target point, and a voltage is applied between the two wire rods. An arc is generated between the tips, a set point of the primary gas flow is set in the vicinity of the target point, and inclined with respect to the spray axis from a plurality of locations around the area where the two wire guide pipes are provided A plurality of beam-like primary gas flows directed toward the assembly point along the direction are generated, and the two wire rods projecting from the two wire rod guide pipes are included from a position before the target point. Further forward than the target point Generating a secondary gas flow that flows so as to converge toward the focusing point on the spray axis set at the position of
A spray flow of molten metal is generated by intensively spraying the primary gas stream on a portion melted by an arc at the tip of the two wires ;
Arc spraying method and performing thermal spraying is ejected toward the object to be sprayed product spray flow of molten metal is arranged in front of the spraying direction together with the secondary gas flow.

An annular member that is provided so that the central axis coincides with an axis along the spraying direction (hereinafter referred to as a spraying axis) and that has a hole opening inside at a front end in the spraying direction, and the central axis is the spraying axis. And the tip is provided to surround the hole continuously or intermittently in a state of being inclined along the direction of focusing at the focusing point set on the spraying axis, and the tip is forward of the spraying direction. A head body having an orifice opened to the side, and a hole penetrating through the hole of the annular member and having a tip that terminates near the opening position of the hole. A thermal spraying head comprising two wire guide tubes configured to guide a thermal spray wire toward a target point set between the points and set on the thermal spray axis; An arc is generated between the ends of the wire May be provided with a feeding means for feeding between the two wires for,
Set the primary gas flow gathering point near the target point,
A plurality of beam-shaped primarys directed toward the set point along a direction inclined with respect to the spray axis from a plurality of locations in a region outside the region where the two wire guide tubes in the hole of the head body are arranged Creating a gas flow and a secondary gas flow that is ejected from the orifice and focused to the focusing point;
A spray flow of molten metal is generated by intensively spraying the primary gas stream on a portion melted by an arc at the tip of the two wires ;
An arc spraying method characterized in that spraying is performed by spraying the molten metal spray flow together with the secondary gas flow toward an object to be sprayed disposed in front of the spraying direction.

3. The arc spraying method according to claim 1, wherein at least a part of the plurality of primary gas flows is brought into contact with the vicinity of the tip portions of the two guide tubes.

Two wire rods for thermal spraying are fed toward the target point while being guided by two wire rod guide tubes each having a tip directed to a target point set on an axis line (hereinafter referred to as a spray axis) along the spraying direction. The two wire rods for thermal spraying projecting from the tip ends of the two wire rod guide pipes are brought into contact with each other in the vicinity of the target point, and a voltage is applied between the two wire rods. An arc is generated between the tips, a primary gas flow path is formed along the longitudinal direction of each of the two wire rod guide pipes, and the tip opens to the target point side. The primary gas flow toward the target point is generated along the outer surface of the wire rod projecting from the two wire rod guide tubes, and the wire rod projecting from the tip of each of the two wire rod guide tubes is included. Than the target point Generating a secondary gas flow that flows so as to converge toward the converging point on the spraying axis set at a position further forward than the target point from the front position;
A spray flow of molten metal is generated by intensively spraying the primary gas stream on a portion melted by an arc at the tip of the two wires ;
An arc spraying method characterized in that spraying is performed by spraying the molten metal spray flow together with the secondary gas flow toward an object to be sprayed disposed in front of the spraying direction.

The arc spraying method according to any one of claims 1 to 4, wherein a flow velocity of the primary gas flow is set according to a type of the wire for thermal spraying.

An annular member that is provided so that a central axis coincides with an axis along the spraying direction (hereinafter referred to as a spraying axis) and that has a hole inside that has a tip opened forward in the spraying direction, and the central axis is the spraying axis. And the tip is provided in front of the spraying direction so as to surround the hole continuously or intermittently in a state of being inclined along the direction of focusing at the focusing point set on the spraying axis. A head main body having an orifice opened to the side and a gas reservoir chamber communicated with the rear end portion of the orifice, and a tip of the annular member penetrating through a hole portion of the annular member. 2 configured to guide the wire for thermal spraying toward a target point set on the spray axis while being positioned between the opening position of the hole and the focusing point. A wire guide tube of the book, A spray head having a primary gas flow forming means inside the Jo member causes the primary gas flowing in the front side of the thermal spraying direction,
Secondary gas supply means for supplying a compressed secondary gas to the gas reservoir chamber in order to eject the secondary gas from the orifice;
Power supply means for supplying power between the two wires in order to generate an arc between the ends of the two wires,
Metal spraying is performed by spraying a molten metal spray flow formed by spraying the primary gas flow in the vicinity of the tip portions of the two wires in which arcs are generated together with the secondary gas flow in the spraying direction. In arc spraying equipment,
A set point of primary gas flow is set near the target point,
The primary gas flow forming means is arranged along a direction inclined with respect to the spray axis from a plurality of locations in a region outside the region where the two wire guide tubes are disposed in the hole inside the annular member. Inclined with respect to the spray axis so as to generate a plurality of beam-like primary gas flows that flow toward the assembly point and are intensively blown to a portion melted by an arc at the tip of the two wires. Provided with a plurality of primary gas passages whose tips are directed to the assembly point in the hole,
At least some of the primary gas flow paths among the plurality of primary gas flow paths are provided so as to generate a primary gas flow that flows in contact with the vicinity of the tip portions of the two guide tubes. Arc spraying equipment.

The two wire rod guide pipes for guiding the two wire rods are provided in a state where a center line along each guide direction is positioned on a plane including the central axis of the annular member,
Four primary gas flow paths are provided at intervals of 90 degrees around the central axis of the annular member, and two of the four primary gas flow paths are respectively connected to the center lines. The arc spraying device according to claim 6, wherein the arc spraying device is provided in a state where the center line of the two wire rod guide tubes is positioned on a plane on which the center line is disposed.

The two wire rod guide pipes that respectively guide the two wire rods are provided in a state where a center line along each guide direction is positioned on a plane including the spray axis.
Four primary gas flow paths are provided around the spray axis at 90 ° intervals, and each of the two primary gas flow paths at diagonal positions has their center lines as the two wire guide pipes. The arc spraying device according to claim 6, wherein the arc spraying device is provided in a state of being positioned on a plane inclined by 45 degrees with respect to a plane on which the center line of the arc is arranged.

An annular member that is provided so that the central axis coincides with an axis along the spraying direction (hereinafter referred to as a spraying axis) and that has a hole opening inside at a front end in the spraying direction, and the central axis is the spraying axis. And the tip is provided to surround the hole continuously or intermittently in a state of being inclined along the direction of focusing at the focusing point set on the spraying axis, and the tip is forward of the spraying direction. A head body having an orifice opened to the side and a gas reservoir chamber communicated with the rear end portion of the orifice, and the tip of the annular member passes through the hole and terminates in the vicinity of the opening position of the hole. 2 is configured to guide the thermal spray wire toward a target point set on the thermal spray axis while being positioned between the opening position of the hole and the focusing point. A wire guide tube of the book, A spray head having a primary gas flow forming means inside the Jo member causes the primary gas flowing in the front side of the thermal spraying direction,
Secondary gas supply means for supplying a secondary gas compressed into the gas reservoir chamber in order to eject the secondary gas from the orifice;
Power supply means for supplying power between the two wires in order to generate an arc between the tips of the two wires,
Metal spraying is performed by spraying a molten metal spray flow formed by spraying the primary gas flow near the tips of the two wire rods where arcs are generated in the spraying direction together with the secondary gas flow. In arc spraying equipment,
A primary gas that is formed along the longitudinal direction of each of the two wire rod guide tubes , has a tip opened to the target point side, and flows a primary gas along a direction inclined with respect to the spray axis. A primary gas supply means for supplying a primary gas compressed to the primary gas flow path, and the primary gas flow forming means is constituted by the primary gas supply means and each primary gas flow path. ,
An arc spraying apparatus configured such that the primary gas flowing through the primary gas flow path is intensively sprayed onto a portion melted by an arc at the tip of the two wire rods .

The arc spray device according to claim 9, wherein the primary gas flow path is formed so as to coaxially surround the wire guided by each wire guide tube.

The arc spray device according to any one of claims 5 to 10, wherein a flow rate of the primary gas flow is set according to a type of the wire for thermal spraying.