JP3963215B2

JP3963215B2 - Method for joining pipe-shaped members

Info

Publication number: JP3963215B2
Application number: JP2002038045A
Authority: JP
Inventors: 正樹熊谷; 直田中
Original assignee: Sumitomo Light Metal Industries Ltd
Current assignee: Sumitomo Light Metal Industries Ltd
Priority date: 2002-02-15
Filing date: 2002-02-15
Publication date: 2007-08-22
Anticipated expiration: 2022-02-15
Also published as: JP2003236682A

Description

【０００１】
【技術分野】
本発明は、パイプ状部材の接合方法に係り、特に接合後において、優れた接合強度が確保され得るパイプ状部材の接合方法に関するものである。
【０００２】
【背景技術】
従来より、アルミニウム若しくはアルミニウム合金からなるパイプ状乃至はロッド状（中実の棒状）のアルミニウム部材を接合する方法の一つとして、摩擦圧接法が知られている。この摩擦圧接法は、接合されるべきアルミニウム部材を互いに突き合わせて、相対的に高速回転せしめ、それらの突合せ面に発生する摩擦熱で、それぞれの突合せ部を軟化、溶融させて、圧接せしめる方法であり、アルミニウムやアルミニウム合金材料の溶接手法として一般に採用されるＴＩＧやＭＩＧ等による溶接手法とは異なって、不活性ガス等を使用する必要がない等の利点があるものの、接合されるべきアルミニウム部材のうちの一方を高速で回転させるために、回転せしめられるアルミニウム部材の大きさによっては、大きな装置が必要となると共に、アルミニウム部材を固定するために、パイプの形状が限定されて、異なる径断面を有するアルミニウム部材同士を接合することは、困難であったのである。また、それぞれの突合せ部の溶融部分に対して、互いの突合せ方向に圧力を掛けて、かかる溶融部分をバリとして排出させるため、接合されるべきアルミニウム部材のそれぞれの長さが、接合の前後で不定量に変化してしまい、それ故に、所望の長さの接合製品を安定して得ることが困難となる等といった欠点を有していた。
【０００３】
そのため、近年では、アルミニウム部材自体を回転せしめるのではなく、それ以外の第三の部材（工具）を用いて、アルミニウム部材を接合せしめる手法、所謂摩擦攪拌接合法が注目され、パイプ状やロッド状を呈するアルミニウム部材の接合に際しても適用され始めてきている。
【０００４】
かかる摩擦撹拌接合法は、摩擦熱を利用した固相接合法であって、入熱が少なく、接合時に生ずる接合部位の軟化や熱歪みの程度を可及的に少なく抑え得る接合手法として知られており、例えば、図１（ａ）に示されるように、接合されるべき二つのアルミニウム部材２，４を互いに突き合わせる一方、それら二つのアルミニウム部材２，４よりも硬い材質のピン６が先端中心部に同心的に設けられてなる回転工具８を高速回転せしめつつ、該ピン６を、該二つのアルミニウム部材２，４の突合せ部１０に圧入し、かかる突合せ部１０に沿って相対移動せしめることにより、それら回転せしめられるピン６や回転工具８と二つのアルミニウム部材との間に摩擦熱を発生せしめ、そしてその摩擦熱にて、突合せ部１０の周辺部位を塑性流動可能な状態と為し、更にピン６の高速回転による撹拌作用にて二つのアルミニウム部材２，４の突合せ部１０の組織を入り交わらせ、以て二つのアルミニウム部材２，４を溶融させることなく、接合するものである。
【０００５】
このような摩擦撹拌接合法によれば、接合されるべき二つのアルミニウム部材２，４よりも充分に小さな回転工具８だけが高速回転せしめられるため、アルミニウム部材２，４の大きさに拘わらず、装置全体の大きさを比較的に小さく為すことが出来、また二つのアルミニウム部材２，４のそれぞれの突合せ部１０に対して、互いの突合せ方向に、それほど大きな圧力が掛けられるものでないところから、接合時に生ずるバリにより、接合の前後で、二つのアルミニウム部材２，４の長さが不定量に変化するようなことも殆どないのであり、以て上述の摩擦圧接法の実施時に生ずる問題も、悉く解消され得ることとなる。
【０００６】
ところが、かくの如き従来の摩擦撹拌接合手法にて、図１（ａ）に示される如きパイプ状のアルミニウム部材２を、同一の外径を有するパイプ状のアルミニウム部材乃至はロッド状のアルミニウム部材４に対して接合するに際しては、一般に、図１（ｂ）に示されるように、回転工具８は、進行方向（図中、矢印イにて示される方向）に対して、所定の角度（α）をもって後傾する形態において、相対的に移動せしめられることとなるところから、接合後において、図２に示されるように、二つのアルミニウム部材２，４が互いに攪拌されてなる接合部（攪拌部）１４の表面に、後傾した回転工具８の肩部１２、特にエッジ部がアルミニウム部材２，４の外表面に食い込むことによって惹起される窪み１６が、周方向に亘って必然的に形成されてしまい、元々、比較的に薄肉であるパイプ状のアルミニウム部材２が、かかる接合部１４において、薄肉のパイプ状アルミニウム部材２の肉厚よりも実質的に薄肉となり、これによって、破断強度乃至は引張強度や疲労強度（曲げ強度）等が低下して、接合強度が低下し、その結果、継手効率が低下するといった大きな問題があった。
【０００７】
【解決課題】
ここにおいて、本発明は、上述せる如き事情を背景にして為されたものであって、その解決課題とするところは、摩擦撹拌接合手法を利用して、パイプ状若しくはロッド状の部材とパイプ状の部材とを、優れた接合強度をもって、効率的に接合することが出来、以て継手効率を極めて高度に確保することが出来る、パイプ状部材の接合方法を提供することにある。
【０００８】
【解決手段】
そして、本発明は、上述の如き課題を解決するために、パイプ状若しくはロッド状の第一の部材に対して、パイプ状の第二の部材の端面を突き合わせて嵌合せしめ、その突合せ部に、回転工具の先端に同心的に設けたピンを、該回転工具と共に一体的に回転させつつ差し込み、相対的に移動させることにより、かかる突合せ部を摩擦攪拌接合して、目的とする接合製品を形成するに際して、前記第一の部材として、前記第二の部材よりも大なる外径を有し且つ肉厚が大となるものを用いると共に、前記回転工具の肩部が、前記第二の部材の外表面よりも部材内側に入り込まないようにして、前記摩擦攪拌接合を行ない、前記突合せ部に形成される接合部の外表面に、該第二の部材の外表面よりも低い窪みが形成されないようにしたことを特徴とするパイプ状部材の接合方法を、その要旨とするものである。
【０００９】
すなわち、このような本発明に従うパイプ状部材の接合方法は、接合すべきパイプ状の部材（第二の部材）の端面を、かかるパイプ状部材よりも外径と肉厚が大きなパイプ状若しくはロッド状の部材（第一の部材）に対して突き合わせて嵌合せしめ、そして、その突合せ部を、先端にピンが設けられた回転工具にて、その肩部が、薄肉である第二のパイプ状部材の外表面よりも部材内側に入り込まないようにして、摩擦攪拌接合を行なっているところから、厚肉である第一の部材よりも強度に劣る第二の部材の外表面に、周方向に亘って、部材内側に入り込むような窪みが形成されることがなく、従って、第二の部材が、かかる窪み形成部分において、部分的に薄肉となり、その薄肉部分において破断強度や疲労強度が低下するようなことが有利に抑制され得るのである。このため、パイプ状若しくはロッド状の第一の部材とパイプ状の第二の部材とを優れた破断強度や疲労強度をもって、確実に且つ効率的に接合することが出来るのであり、それによって、極めて高度な継手効率を有する接合製品を有利に得ることが可能となるのである。
【００１０】
なお、このような本発明に従うパイプ状部材の接合方法の好ましい態様の一つによれば、前記回転工具の軸心が前記第一及び第二の部材の軸心に対して直交するようにして、前記摩擦攪拌接合が行なわれることとなる。このような本発明手法に従えば、回転工具の肩部が薄肉の第二の部材の外表面に接触するようなことが効果的に回避され得、従って、第二の部材の肩部との接触部分が塑性流動化して、該外表面に窪みが形成され、以て、第二の部材が薄肉化してしまうようなことが、極めて効果的に防止され得るのであり、これにより、本発明の目的がより一層有利に達成され得ることとなる。
【００１１】
また、かかる本発明に従うパイプ状部材の接合方法の有利な別の態様の一つによれば、前記第一及び第二の部材の軸心に対して垂直となる該第一及び第二の部材の当接面に対し、前記回転工具の軸心が該第二の部材側に傾斜せしめられてなる形態において、前記摩擦攪拌接合が行なわれる。このような本発明手法に従えば、接合後において、第一の部材の接合端部が、滑らかな傾斜面形態と為され得、これによって、より一層優れた接合品質が確保され得るのである。
【００１２】
加えて、本発明における好ましい別の態様の一つによれば、前記第一の部材の端部外周部に段付き部が形成され、該段付き部の小径部に前記第二の部材の端部が外嵌せしめられて、それら第一及び第二の部材が突き合わされることが望ましい。このような構成を採用することによって、回転工具の押圧力乃至は押付け力によって、第二の部材の端部が変形せしめられるようなことが有利に阻止され得るのであり、従って、かかる第二の部材の端部の内孔内に、中子の如き裏当て治具を設置する手数も何等必要とされ得ないのである。
【００１３】
【発明の実施の形態】
ところで、かくの如き本発明に従うパイプ状部材の接合方法は、所定のパイプ状の部材を、パイプ状若しくはロッド状の部材に対して接合するに際して、適用されるものであるが、かかる本発明手法に従って接合される部材の材質としては、特に限定されるものではなく、例えば、アルミニウム若しくはアルミニウム合金からなるアルミニウム製部材や、銅若しくは銅合金からなる銅製部材等の金属製部材が、適宜に選択されて、用いられるのである。そして、その中でも、接合部位の組織変化によって、接合強度の低下が惹起されないものが、強度維持の上で有利に用いられ得るのであり、アルミニウム製部材としては、例えば、Ａｌ−Ｃｕ−Ｍｇ系（２０００系）、Ａｌ−Ｍｇ系（５０００系）、Ａｌ−Ｍｇ−Ｓｉ系（６０００系）、Ａｌ−Ｚｎ−Ｍｇ系（７０００系）のアルミニウム部材等を例示することが出来る。
【００１４】
そして、そのような材質の中でも、アルミニウム合金からなる二つのアルミニウム部材を摩擦攪拌接合して、目的とする接合製品を形成せしめるに際しては、先ず、図３に示されるように、第一の部材たるロッド状アルミニウム部材２０と第二の部材たるパイプ状アルミニウム部材２２とを、それぞれの端面同士において、同軸的に突き合わせて嵌合せしめた状態下で、それら二つのアルミニウム部材２０，２２が周方向及び軸方向に相対的に移動することがないように、拘束し、保持せしめるのである。
【００１５】
なお、かかる中実の棒形状を呈するロッド状アルミニウム部材２０としては、本発明に従って、それに接合されるパイプ状アルミニウム部材２２に比して、大きな外径を有するものが用いられており、それ故、当然のことながら、その肉厚は、パイプ状アルミニウム部材２２よりも厚いものとなっている。また、その先端外周部は段付き部とされ、端面中央部に位置するように、パイプ状アルミニウム部材２２の内孔内に嵌合可能な小径円柱状の嵌合突起２４が、同心的に一体形成されている。そして、この嵌合突起２４を、パイプ状アルミニウム部材２２内に、それらパイプ状アルミニウム部材２２とロッド状アルミニウム部材２０の端面同士が突き合わされるまで、嵌挿せしめることによって、それら二つのアルミニウム部材２０，２２が、容易に同軸的に組み付けられるようになっているのである。また、突き合わされたアルミニウム部材２０，２２の突合せ部２６には、それらの外径差に基づくところの段差部２８が、全周に亘って、周方向に連続して延びるように、形成されている。
【００１６】
一方、摩擦攪拌接合操作に用いられる回転工具３０としては、軸回りに回転せしめられるロッド状本体の先端部に、所定高さを有するピン３２が同心的に設けられている、従来と同様なものが使用され、また、接合されるべきアルミニウム部材２０，２２の材質よりも硬い材料にて形成されており、そのため、それら回転工具３０やピン３２が高速回転せしめられて、二つのアルミニウム部材２０，２２の突合せ部２６に差し込まれたり、段差部２８に回転工具３０の先端部たる肩部（ショルダ部）３４が接触せしめられても、殆ど損耗することのない非消費型の部材とされているのである。なお、これら回転工具３０やピン３２の軸心回りの高速回転は、回転工具３０の基部側において、図示しない、従来と同様な回転駆動装置に取り付けられていることによって、容易に実現され得るようになっているのである。
【００１７】
そして、摩擦攪拌接合操作においては、そのような回転工具３０をピン３２と一体的に高速回転させて、図３に示されるように、同軸的に突き合わされたロッド状アルミニウム部材２０とパイプ状アルミニウム部材２２との突合せ部２６に向かって、下降するように、移動させることにより、かかる突合せ部２６に、該回転工具３０のピン３２を押し付けて、回転工具３０の肩部３４が段差部２８に当接するまで、該ピン３２を突合せ部２６に差し込むようにするのである。これにより、突合せ部２６とピン３２及び回転工具３０の肩部３４との接触面において摩擦熱を発生させて、その周囲を可塑化せしめると共に、ピン３２の高速回転に伴う攪拌作用にて、突合せ部２６を形成するロッド状アルミニウム部材２０とパイプ状アルミニウム部材２２のそれぞれの端部部位の組織を入り交じり合わせ、更に、かかるピン３２及び回転工具３０を突合せ部２６に沿って相対的に移動せしめることにより、二つのアルミニウム部材２０，２２を、その突合せ部２６において、摩擦攪拌接合せしめるのである。
【００１８】
なお、本実施形態においては、かくの如き摩擦攪拌接合に際して、回転工具３０は、図４に示されるように、その軸心：ａが、ロッド状アルミニウム部材２０とパイプ状アルミニウム部材２２の軸心：ｂ，ｃに対して直交（θ₁）した状態において、そして、周方向（接合進行方向）への相対的な移動をより円滑にすべく、図５に示されるように、回転工具３０の軸心：ａが、軸心：ｂ，ｃを含む垂直面：ｄに対して所定の角度：θ₂を為すように、傾斜せしめられた状態において、位置が固定されるのである。また、そのような位置固定的な、高速回転せしめられる回転工具３０に対して、相対移動不能に拘束された二つのアルミニウム部材２０，２２が軸心回り（図５において矢印ロにて示される方向）に一体回転せしめられることにより、全体として、回転工具３０が、進行方向（図５において矢印ハにて示される方向）において所定の角度：θ₂をもって後傾する形態において、突合せ部２６に沿って、周方向に相対的に移動せしめられるようになっている。
【００１９】
また、ここにおいて、回転工具３０の傾斜角度（θ₂）としては、従来と同様な角度が採用され得るのであるが、本発明にあっては、特に、回転工具３０の肩部３４が、小径且つ薄肉であるパイプ状アルミニウム部材２２の外表面３６に接触して部材内側に入り込んで窪みが形成されることのないような角度が、適宜に設定されることとなる。
【００２０】
而して、上述せる如くして、摩擦攪拌接合操作が行なわれることにより、ロッド状アルミニウム部材２０とパイプ状アルミニウム部材２２との突合せ部２６には、図６及び図７に示されるように、それら二つのアルミニウム部材２０，２２に跨る接合部（攪拌接合部）３８が、全周に亘って、周方向に連続的に延びるように形成せしめられ、目的とする接合製品が得られるのである。また、そのような接合部３８の形成過程において、パイプ状アルミニウム材２２の端部と突合せ部２６における段差部２８とが塑性流動して交じり合う際に、塑性流動化せしめられた段差部２８が、回転工具３０の肩部３４にて、押し付けられ、均されることによって、接合部３８の外表面４０が、回転工具３０の肩部３４に対応した平面形態とされると共に、かかる接合部３８の外表面４０が、パイプ状アルミニウム部材２２の外表面３６よりも外径方向に高く、且つ、ロッド状アルミニウム部材２０の外表面４２よりも低くされ、以て、かかる接合部３８とその両側のアルミニウム部材２０，２２にて、階段状の段差部が形成されるようになっているのである。
【００２１】
このように、本実施形態では、突合せ部２６を、ピン３２が設けられた回転工具３０にて摩擦攪拌接合せしめる際において、回転工具３０の肩部３４が、ロッド状アルミニウム部材２０に比して小径・薄肉であるパイプ状アルミニウム部材２２の外表面３６よりも径方向内方に、つまり、部材内側に入り込まないようにしているところから、ロッド状アルミニウム部材２０よりも強度に劣るパイプ状アルミニウム部材２２の外表面３６に、周方向に亘って窪みが形成されるようなことが、効果的に防止されるのである。そのため、パイプ状アルミニウム部材２２が、接合部３８において、部分的に薄肉となり、その薄肉部分において破断強度や疲労強度が低下するようなことが有利に抑制され得るのであり、以て、優れた継手効率を有する接合製品を、極めて有利に形成せしめることが出来るのである。
【００２２】
また、本実施形態においては、回転工具３０の軸心：ａと、ロッド状アルミニウム部材２０の軸心：ｂ（パイプ状アルミニウム部材２２の軸心：ｃ）との為す角：θ₁が、直角となるようにして、摩擦攪拌接合が行なわれているところから、かかる角：θ₁が鋭角となる形態において実施される場合に比して、回転工具３０の肩部３４が、パイプ状アルミニウム部材２２の外表面３６に接触するようなことが、より一層効果的に回避され得ているのである。
【００２３】
加えて、ロッド状アルミニウム部材２０の嵌合突起２４がパイプ状アルミニウム部材２２の内孔内に挿入位置せしめられた状態において、摩擦攪拌接合が行なわれているところから、回転工具３０の突合せ部２６に対する押圧力によって、パイプ状アルミニウム部材２２の端部が変形せしめられることも、有利に阻止され得ているのである。
【００２４】
ところで、本発明手法は、上述した実施形態に限定して解釈されるものでは決してなく、図８及び図９には、互いに径及び肉厚の異なるパイプ状アルミニウム同士を摩擦攪拌接合するに際して、本発明手法を適用した別の実施形態が示されている。なお、それら図８及び図９においては、上述の実施形態と同一の構造とされた部材及び部位については、図中、それぞれ、上述の実施形態と同一の符号を付与することにより、その詳細な説明は、省略した。
【００２５】
すなわち、図８に示される如き、外径、内径及び肉厚の異なるパイプ状アルミニウム部材同士を摩擦攪拌接合するには、先ず、上記の実施形態と同様にして、二つの第一及び第二のパイプ状アルミニウム部材５０，５２を、それぞれの端面同士において同軸的に突き合わせて嵌合せしめた状態下で、それら二つの部材５０，５２が、周方向及び軸方向に、相対的に移動することがないように拘束し、保持せしめられるのである。
【００２６】
なお、ここにおいて、第一のパイプ状アルミニウム部材５０は、第二のパイプ状アルミニウム部材５２より大きな外径且つ小さな内径を有し、以て、肉厚が、第二のパイプ状アルミニウム部材５２に比して、充分に大きくなっており、その先端面には、外周部に設けた段付き部によって、第二のパイプ状アルミニウム部材５２の内孔内に嵌合可能な小径円筒状の嵌合突起５４が、同心的に一体形成されている。そして、この嵌合突起５４を第二のパイプ状アルミニウム部材５２内に、それら第一と第二の部材５０，５２の端面同士が突き合わされるまで、挿入せしめることによって、それら二つの部材５０，５２が、容易に同軸的に位置せしめられるようになっているのである。また、突き合わされた二つの部材５０，５２の突合せ部５６には、上記実施形態と同様に、それらの外径差に基づくところの段差部５８が、全周に亘って、周方向に連続して延びるように形成されることとなる。
【００２７】
そして、上記した実施形態と同様に、高速回転せしめられた回転工具３０のピン３２を、二つの部材５０，５２の突合せ部５６に差し込み、それら二つの部材５０，５２を軸心回りに一体回転せしめることにより、該回転工具３０を突合せ部５６に沿って周方向に相対的に移動せしめて、かかる突合せ部５６を周方向に亘って、摩擦攪拌接合し、目的とする接合製品得を形成するのであるが、本実施形態にあっては、図８に示されるように、回転工具３０の軸心：ａ’が、二つの部材５０，５２の軸心に対して垂直な突合せ面（二つの部材５０，５２の当接面）から、第二のパイプ状アルミニウム部材５２の方向に、傾斜角度：θ₃だけ、傾斜せしめられた形態において、摩擦攪拌接合が行なわれているのである。
【００２８】
具体的には、回転工具３０のピン３２が、第一のパイプ状アルミニウム部材５０の突合せ端面と、第二のパイプ状アルミニウム部材５２の外表面６０とで形成される角部６２に、傾斜角度：θ₃をもって斜めに差し込まれ、その傾斜を保持した状態において、周方向に亘って、摩擦攪拌接合が行なわれるのであり、この際においても、回転工具３０の肩部３４が、薄肉側の第二のパイプ状アルミニウム部材５２の外表面に対して、何等接触することがないように、回転工具３０の傾斜角度が調整されつつ、回転工具３０とピン３２とが、角部６２に沿って、移動せしめられることとなる。これによって、図９に示されるように、接合部６４の外表面６６に、第二のパイプ状アルミニウム部材５２の外表面６０よりも径方向内方に凹陥するような窪みが形成されて、第二のパイプ状アルミニウム部材５２が薄肉化されるようなことが極めて効果的に防止され得、以て、優れた接合強度と継手効率が有利に実現され得る接合製品が得られるのである。しかも、そのような接合部６４の形成過程において、可塑化された突合せ部５６の肉部の逃げが回転工具３０の肩部３４にて抑制されるようになるところから、接合部６４の外表面６６は、回転工具３０の傾斜角度：θ₃に応じた角度を有する、滑らかな傾斜面形態とされ得るのであり、これによって、より一層優れた接合品質が確保され得ることとなるのである。
【００２９】
さらに、本実施形態においては、第一のパイプ状アルミニウム部材５０の円筒状嵌合突起５４が第二のパイプ状アルミニウム部材５２の内孔内に挿入位置せしめられた状態において、摩擦攪拌接合が行なわれているところから、回転工具３０の突合せ部２６に対する押圧力によって、パイプ状アルミニウム部材２２の端部が変形せしめられることも、有利に阻止され得、それら二つのパイプ状アルミニウム部材５０，５２の端部の内孔内に、中子の如き裏当て治具を設置する手数も何等必要とされないのである。
【００３０】
以上、本発明の代表的な実施形態について詳述してきたが、それは、あくまでも例示に過ぎないものであって、本発明は、そのような実施形態に係る具体的な記述によって、何等限定的に解釈されるものではないことが、理解されるべきである。
【００３１】
例えば、上記の実施形態では、互いに突き合わされた二つのアルミニウム部材２０，２２，５０，５２を軸心回りに一体回転せしめて、回転工具３０を突合せ部２６，５６に沿って相対移動せしめていたが、アルミニウム部材２０，２２，５０，５２を固定して、回転工具３０を突合せ部２６，５６に沿って周方向に移動せしめるようにしても、或いは、アルミニウム部材２０，２２，５０，５２を軸心回りに一体回転せしめつつ、回転工具３０を周方向に移動せしめるようにしても良いのである。
【００３２】
また、上記した本実施形態では、外径及び肉厚の大きなロッド状若しくはパイプ状アルミニウム部材２０，５０と、外径及び肉厚の小さなパイプ状アルミニウム部材２２，５２とが用いられて、目的とする接合製品が形成されていたが、それらの突合される部材同士の外径差は、特に制限されるものではないものの、接合部３８，６４の外表面４０，６６に、薄肉の第二の部材２２，５２の外表面３６，６０よりも低い窪みが出来ないように、また、突合せ部２６，５６に差し込まれたピン３２の撹拌作用が健全に実施され得るように、適宜に設定されることとなる。
【００３３】
かくして、本発明手法にて形成された接合製品は、そのまま、或いは、時効処理にて硬化せしめられたり等した後、アーム用部材やサブフレーム用部材等の自動車用部品等として、有利に用いられることとなるのである。
【００３４】
その他、一々列挙はしないが、本発明が、当業者の知識に基づいて、種々なる変更、修正、改良等を加えた態様において実施され得るものであり、また、そのような実施態様が、本発明の趣旨を逸脱しない限り、何れも、本発明の範囲内に含まれるものであることは、言うまでもないところである。
【００３５】
【実施例】
以下に、本発明の代表的な実施例を示し、本発明を更に具体的に明らかにすることとするが、本発明が、そのような実施例の記載によって、何等の制約をも受けるものでないことは、言うまでもないところである。
【００３６】
実施例１
先ず、第一の部材として、外径が３２ｍｍのロッド状アルミニウム部材（６Ｎ０１−Ｔ１材）を準備する一方、第二の部材として、３０ｍｍの外径と４ｍｍの厚さとを有するパイプ状アルミニウム部材（６Ｎ０１−Ｔ１材）を準備した。なお、第一の部材の一端面には、第二の部材の内径と略同様な直径を有する１０ｍｍ長さの円柱状嵌合突起が一体的に形成されていた。
【００３７】
次いで、それら準備された二つのロッド状アルミニウム部材とパイプ状アルミニウム部材とを、該ロッド状アルミニウム部材の嵌合突起をパイプ状アルミニウム部材の内孔内に挿嵌せしめつつ、互いに同軸上で突き合わせた後、それら二つのアルミニウム部材が突合せ部において相対的に移動しないように拘束し、図８に示される如き形態において、先端にピンが設けられた回転工具を高速回転させつつ、かかる回転工具のピンを、回転工具の軸心が二つのアルミニウム部材の軸心に対して垂直となる当接面に対し、パイプ状アルミニウム部材側に傾斜するように、即ち、図８におけるθ₃が５°となるようにして、二つのアルミニウム部材の突合せ部に差し込んで、それら二つのアルミニウム部材を、その軸心回りに一体的に回転せしめることにより、回転工具を該突合せ部に沿って周方向に移動させることにより、それらロッド状アルミニウム部材とパイプ状アルミニウム部材とを摩擦撹拌接合した。
【００３８】
なお、かかる摩擦撹拌接合には、回転工具として、ピン直径：３ｍｍ、ピン高さ：４．５ｍｍのピンが同心的に設けられた、回転工具肩径：１０ｍｍであるものを用いると共に、回転数：１０００ｒｐｍ、外周での接合速度１２０ｍｍ／分、及び、回転工具が進行方向において後傾する傾斜角度（θ₂）：３°の条件を採用した。
【００３９】
そして、かかる摩擦攪拌接合によって得られた接合製品に対して、１８５℃、８時間の条件にて、時効処理を行なった。
【００４０】
そして、上述せる如くして得られた接合製品と、それの母材の一方である薄肉側のパイプ状アルミニウム部材とを、それぞれ、ＪＩＳ−Ｚ−３１１１−１９７０の「３．試験方法」に準拠して、軸方向に引張することにより、引張試験を実施した。その結果、接合製品の破断は、パイプ状アルミニウム部材側の母材で生じ、その破断強度（引張強度）はパイプ状アルミニウム部材と同じであり、かかるパイプ状アルミニウム部材を基準とした継手効率［＝（接合品の破断強度）／（母材の破断強度）×１００］は１００％であった。また、接合部（ビード）は略平滑で、その接合部断面の組織観察を実施したところ、パイプ状アルミニウム部材の外表面より低い窪み等の欠陥の発生はなく、健全な接合状態であることを確認した。加えて、常法に従って、接合製品とパイプ状アルミニウム部材の疲労試験を行なったところ、接合製品の疲労強度は、パイプ状アルミニウム部材の疲労強度と略同じであった。
【００４１】
比較例１
また、比較のために、第二の部材として、上記した実施例１と同様なパイプ状アルミニウム部材（６Ｎ０１−Ｔ１材）を準備する一方、第一の部材として、該パイプ状アルミニウム部材と同一外径を有する、外径：３０ｍｍのロッド状アルミニウム部材（６Ｎ０１−Ｔ１材）を準備した。なお、かかる第一の部材の一端面には、第二の部材の内径と略同様な直径を有する１０ｍｍ長さの円柱状嵌合突起が一体的に形成されていた。
【００４２】
そして、それら二つのアルミニウム部材を、前記実施例１と同様にして、それと同一の条件で摩擦撹拌接合した（但し、回転工具の軸心が二つのアルミニウム部材の軸心に対して直交するようにした）。その後、１８５℃、８時間の条件で時効処理を行なって、接合製品を作製した。
【００４３】
そして、得られた接合製品を、ＪＩＳ−Ｚ−３１１１−１９７０の「３．試験方法」に準拠して、軸方向に引張することにより、引張試験を実施した。その結果、接合製品の破断は、接合部で生じ、パイプ状アルミニウム部材を基準とした継手効率は９２％であった。また、その接合部断面の組織観察を実施したところ、接合部には、窪みが生じており、かかる窪み部分から破断が生じていることが認められた。加えて、常法に従って、接合製品の疲労試験を行なったところ、１０⁶回付近で、母材の約１０％程度の疲労強度しかなかった。
【００４４】
かかる実施例１及び比較例１の結果から明らかなように、本発明手法にて形成された接合製品にあっては、比較例のものに比して、破断強度及び疲労強度に優れ、接合による強度の低下が極めて効果的に回避され、母材と同様な強度が確保されていることが分かるのである。
【００４５】
【発明の効果】
以上の説明からも明らかなように、本発明に従うパイプ状部材の接合方法によれば、パイプ状の部材が、パイプ状若しくはロッド状の部材に対して、優れた接合強度をもって、効率的に且つ確実に接合されるのであり、以て極めて高度な継手効率は確保され得ることとなるのである。
【図面の簡単な説明】
【図１】従来の手法にて、同一外径を有するロッド状アルミニウム部材とパイプ状アルミニウム部材を摩擦撹拌接合する工程の一例を示す説明図であって、（ａ）は、それら二つのアルミニウム部材を突き合わせた状態の断面説明図であり、（ｂ）は、（ａ）における右側側面説明図である。
【図２】従来の手法にて得られる接合製品における接合部の形態を示す部分拡大断面説明図である。
【図３】本発明手法に従って、ロッド状アルミニウム部材とパイプ状アルミニウム部材を摩擦撹拌接合する工程の一例を示す説明図であって、それら二つのアルミニウム部材を突き合わせた状態を示している。
【図４】本発明手法に従って、ロッド状アルミニウム部材とパイプ状アルミニウム部材を摩擦撹拌接合する工程の別の例を示す説明図であって、それら二つのアルミニウム部材を突合せ部に回転工具のピンを差し込んだ状態を示している。
【図５】図４における右側側面説明図である。
【図６】本発明手法にて得られる接合製品における接合部の形態を示す部分拡大断面説明図である。
【図７】本発明手法にて得られる接合製品における接合部周辺の形態を示す正面説明図である。
【図８】本発明手法に従って、互いに径及び肉厚の異なるパイプ状アルミニウム部材同士を摩擦撹拌接合する工程の一例を示す説明図であって、図４に対応する図である。
【図９】本発明手法にて得られる接合製品における接合部の別の形態を示す部分拡大断面説明図であって、図６に対応する図である。
【符号の説明】
２０，５０第一の部材２２，５２第二の部材
２４，５４嵌合突起２６，５６突合せ部
２８，５８段差部３０回転工具
３２ピン３４肩部
３６，６０第二の部材の外表面
３８，６４接合部４０，６６接合部の外表面[0001]
【Technical field】
The present invention relates to a method for joining pipe-shaped members, and more particularly to a method for joining pipe-shaped members that can ensure excellent joint strength after joining.
[0002]
[Background]
2. Description of the Related Art Conventionally, a friction welding method is known as one of methods for joining pipe-shaped or rod-shaped (solid rod-shaped) aluminum members made of aluminum or an aluminum alloy. This friction welding method is a method in which the aluminum members to be joined are butted against each other and rotated at a relatively high speed, and the abutting portions are softened and melted by the frictional heat generated on the abutting surfaces, and are brought into pressure welding. Different from welding techniques such as TIG and MIG, which are generally adopted as welding techniques for aluminum and aluminum alloy materials, there are advantages such as no need to use inert gas, etc., but aluminum members to be joined In order to rotate one of them at a high speed, depending on the size of the aluminum member to be rotated, a large device is required, and in order to fix the aluminum member, the shape of the pipe is limited, and different diameter cross sections It was difficult to join the aluminum members having the above. Further, in order to discharge the molten portions as burrs by applying pressure in the abutting direction to the molten portions of the respective butted portions, the respective lengths of the aluminum members to be bonded are before and after the bonding. It has a disadvantage that it changes indefinitely and therefore it is difficult to stably obtain a bonded product having a desired length.
[0003]
Therefore, in recent years, a technique of joining the aluminum member using a third member (tool) other than the aluminum member itself, that is, a so-called friction stir welding method has been attracting attention. It has begun to be applied to the joining of aluminum members exhibiting the above.
[0004]
Such a friction stir welding method is a solid-phase joining method using frictional heat, and is known as a joining method that can reduce the degree of softening and thermal distortion of the joining portion that occurs at the time of joining with less heat input as much as possible. For example, as shown in FIG. 1 (a), two aluminum members 2 and 4 to be joined are abutted against each other, while a pin 6 made of a material harder than the two aluminum members 2 and 4 has a tip. The pin 6 is press-fitted into the abutting portions 10 of the two aluminum members 2 and 4 and is relatively moved along the abutting portions 10 while rotating the rotary tool 8 concentrically provided at the center portion at a high speed. As a result, frictional heat is generated between the two aluminum members and the pin 6 or the rotating tool 8 that can be rotated, and the peripheral portion of the butt portion 10 can be plastically flowed by the frictional heat. In addition, the structure of the butted portion 10 of the two aluminum members 2 and 4 is mixed by the stirring action by the high-speed rotation of the pin 6 so that the two aluminum members 2 and 4 can be joined without melting. To do.
[0005]
According to such a friction stir welding method, only the rotary tool 8 that is sufficiently smaller than the two aluminum members 2 and 4 to be joined is rotated at a high speed. The size of the entire apparatus can be made relatively small, and not so much pressure can be applied to the abutting portions 10 of the two aluminum members 2 and 4 in the abutting direction of each other. Due to burrs that occur during joining, the lengths of the two aluminum members 2 and 4 rarely change indefinitely before and after joining, so the problem that arises when the above-mentioned friction welding method is performed, It can be solved ugly.
[0006]
However, with the conventional friction stir welding method as described above, the pipe-shaped aluminum member 2 as shown in FIG. 1A is replaced with a pipe-shaped aluminum member or rod-shaped aluminum member 4 having the same outer diameter. In general, as shown in FIG. 1 (b), the rotary tool 8 has a predetermined angle (α) with respect to the traveling direction (the direction indicated by the arrow a in the figure). In the form tilted backward, the two aluminum members 2 and 4 are agitated with each other as shown in FIG. 2 after the joining (agitating part). A recess 16 is inevitably formed in the circumferential direction on the surface 14, which is caused by the shoulder 12 of the rotating tool 8 tilted backward, in particular, the edge portion biting into the outer surface of the aluminum members 2, 4. Therefore, the pipe-shaped aluminum member 2 that is originally relatively thin becomes substantially thinner than the thickness of the thin-walled pipe-shaped aluminum member 2 at the joint portion 14. There was a big problem that the tensile strength, fatigue strength (bending strength) and the like were lowered, the joint strength was lowered, and as a result, the joint efficiency was lowered.
[0007]
[Solution]
Here, the present invention has been made in the background as described above, and the problem to be solved is that using a friction stir welding technique, a pipe-shaped or rod-shaped member and a pipe-shaped It is an object of the present invention to provide a pipe-shaped member joining method capable of efficiently joining the above members with excellent joint strength and thereby ensuring a very high joint efficiency.
[0008]
[Solution]
In order to solve the above-described problems, the present invention is configured such that the end surface of the pipe-shaped second member is abutted and fitted to the pipe-shaped or rod-shaped first member, and the butt portion thereof is fitted. Then, a pin provided concentrically at the tip of the rotary tool is inserted while rotating integrally with the rotary tool, and is moved relative to each other, thereby friction stir welding the abutting portion to obtain a target joined product. In forming the first member, the first member having an outer diameter larger than that of the second member and having a large thickness is used, and the shoulder of the rotary tool is used as the second member. The friction stir welding is performed so as not to enter the inside of the member from the outer surface of the second member, and a recess lower than the outer surface of the second member is not formed on the outer surface of the joint formed in the butt portion. Features that made The method for joining a pipe-like member which is intended to its gist.
[0009]
That is, in such a joining method of pipe-like members according to the present invention, the end face of the pipe-like member (second member) to be joined is a pipe-like or rod having a larger outer diameter and wall thickness than the pipe-like member. A second member that has a thin wall at the shoulder with a rotating tool provided with a pin at the tip. Since the friction stir welding is performed so as not to enter the inside of the member from the outer surface of the member, the outer surface of the second member, which is inferior in strength to the thick first member, is circumferentially arranged. Therefore, there is no formation of a recess that enters the inside of the member. Therefore, the second member is partially thin at the recess formation portion, and the breaking strength and fatigue strength are reduced at the thin portion. Something like It is as it can be suppressed to interest. For this reason, it is possible to reliably and efficiently join the pipe-shaped or rod-shaped first member and the pipe-shaped second member with excellent breaking strength and fatigue strength. This makes it possible to advantageously obtain a bonded product having a high joint efficiency.
[0010]
According to one of the preferred embodiments of the pipe-shaped member joining method according to the present invention, the axis of the rotary tool is made to be orthogonal to the axes of the first and second members. The friction stir welding is performed. According to such a method of the present invention, it can be effectively avoided that the shoulder portion of the rotary tool comes into contact with the outer surface of the thin second member. It is possible to extremely effectively prevent the contact portion from being plastically fluidized to form a depression on the outer surface, and thus the second member to be thinned. The object can be achieved even more advantageously.
[0011]
According to another advantageous aspect of the method for joining pipe-like members according to the present invention, the first and second members that are perpendicular to the axial centers of the first and second members. The friction stir welding is performed in a form in which the axis of the rotary tool is inclined to the second member side with respect to the contact surface. According to such a method of the present invention, after joining, the joining end portion of the first member can be formed in a smooth inclined surface form, and thereby even better joining quality can be ensured.
[0012]
In addition, according to another preferable aspect of the present invention, a stepped portion is formed on the outer periphery of the end of the first member, and the end of the second member is formed on the small diameter portion of the stepped portion. It is desirable that the parts are fitted and the first and second members are abutted. By adopting such a configuration, it is possible to advantageously prevent the end of the second member from being deformed by the pressing force or pressing force of the rotary tool. There is no need to install a backing jig such as a core in the inner hole at the end of the member.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
By the way, the pipe-shaped member joining method according to the present invention as described above is applied when joining a predetermined pipe-shaped member to a pipe-shaped or rod-shaped member. The material of the member to be joined according to the above is not particularly limited, and for example, a metal member such as an aluminum member made of aluminum or an aluminum alloy or a copper member made of copper or a copper alloy is appropriately selected. It is used. Among them, those that do not cause a decrease in bonding strength due to a change in the structure of the bonding site can be advantageously used for maintaining the strength. As an aluminum member, for example, an Al—Cu—Mg system ( 2000-based), Al-Mg-based (5000-based), Al-Mg-Si-based (6000-based), Al-Zn-Mg-based (7000-based) aluminum members, and the like.
[0014]
Among such materials, when two aluminum members made of an aluminum alloy are friction stir welded to form a desired joined product, first, as shown in FIG. Under the state in which the rod-shaped aluminum member 20 and the pipe-shaped aluminum member 22 as the second member are coaxially butted and fitted to each other, the two aluminum members 20 and 22 are in the circumferential direction and It is restrained and held so as not to move relatively in the axial direction.
[0015]
As the rod-shaped aluminum member 20 exhibiting such a solid rod shape, a rod-shaped aluminum member 20 having a larger outer diameter is used in comparison with the pipe-shaped aluminum member 22 joined thereto, and therefore. Of course, the wall thickness is thicker than the pipe-like aluminum member 22. The outer peripheral portion of the tip is a stepped portion, and a small-diameter cylindrical fitting protrusion 24 that can be fitted into the inner hole of the pipe-like aluminum member 22 is concentrically integrated so as to be located at the center of the end face. Is formed. The fitting protrusion 24 is inserted into the pipe-shaped aluminum member 22 until the end surfaces of the pipe-shaped aluminum member 22 and the rod-shaped aluminum member 20 are brought into contact with each other, whereby the two aluminum members 20 are inserted. , 22 can be easily coaxially assembled. Further, the butted portion 26 of the butted aluminum members 20 and 22 is formed with a step portion 28 based on a difference in outer diameter thereof so as to continuously extend in the circumferential direction over the entire circumference. Yes.
[0016]
On the other hand, the rotary tool 30 used for the friction stir welding operation is the same as the conventional one in which a pin 32 having a predetermined height is provided concentrically at the tip of the rod-shaped main body rotated around the axis. And is made of a material harder than the material of the aluminum members 20 and 22 to be joined. Therefore, the rotary tool 30 and the pin 32 are rotated at a high speed, and the two aluminum members 20 and 22 are rotated. Even if the shoulder part (shoulder part) 34 which is the front-end | tip part of the rotary tool 30 is made to contact the step part 26 or the level | step-difference part 28, it is set as the non-consumable type member which is hardly worn out. It is. Note that high-speed rotation around the axis of the rotary tool 30 and the pin 32 can be easily realized by being attached to the same rotational drive device (not shown) on the base side of the rotary tool 30. It has become.
[0017]
In the friction stir welding operation, such a rotary tool 30 is rotated at a high speed integrally with the pin 32, and as shown in FIG. 3, the rod-shaped aluminum member 20 and the pipe-shaped aluminum that are coaxially butted together. When the pin 32 of the rotary tool 30 is pressed against the abutting portion 26 by moving the lower end of the rotating tool 30 toward the abutting portion 26 with the member 22, the shoulder portion 34 of the rotating tool 30 is pressed against the stepped portion 28. The pin 32 is inserted into the abutting portion 26 until it abuts. As a result, the butting portion 26, the pin 32, and the shoulder 3 of the rotary tool 30 are provided. 4 Of the rod-shaped aluminum member 20 and the pipe-shaped aluminum member 22 that form the butt portion 26 by the stirring action accompanying the high-speed rotation of the pin 32. By moving the pin 32 and the rotary tool 30 relative to each other along the abutting portion 26, the two aluminum members 20 and 22 are moved at the abutting portion 26. Friction stir welding is performed.
[0018]
In the present embodiment, in the friction stir welding as described above, the rotary tool 30 has an axis a: the axis of the rod-shaped aluminum member 20 and the pipe-shaped aluminum member 22 as shown in FIG. : Orthogonal to b and c (θ ₁ ), And in order to make the relative movement in the circumferential direction (joining progress direction) smoother, as shown in FIG. Vertical plane including c: predetermined angle with respect to d: θ ₂ Thus, the position is fixed in the tilted state. Further, the two aluminum members 20 and 22 restrained so as not to move relative to the rotary tool 30 which is rotated at a high speed and fixed in position are arranged around the axis (the direction indicated by the arrow B in FIG. 5). ) As a whole, the rotary tool 30 as a whole has a predetermined angle: θ in the traveling direction (the direction indicated by the arrow C in FIG. 5). ₂ In the form tilted rearward, it can be moved relative to the circumferential direction along the abutting portion 26.
[0019]
In addition, here, the inclination angle (θ ₂ However, in the present invention, in particular, the shoulder 3 of the rotary tool 30 can be used. 4 However, an angle is set as appropriate so that the outer surface 36 of the small-diameter and thin-walled pipe-shaped aluminum member 22 does not enter the inside of the member and form a recess.
[0020]
Thus, as described above, the friction stir welding operation is performed, so that the abutting portion 26 between the rod-shaped aluminum member 20 and the pipe-shaped aluminum member 22 is as shown in FIG. 6 and FIG. The joining portion (stirring joining portion) 38 straddling the two aluminum members 20 and 22 is formed so as to continuously extend in the circumferential direction over the entire circumference, and the intended joined product is obtained. Further, in the process of forming such a joint portion 38, when the end portion of the pipe-shaped aluminum material 22 and the step portion 28 in the butt portion 26 are plastically flowed and merged, the step portion 28 plastically fluidized is formed. By pressing and leveling at the shoulder portion 34 of the rotary tool 30, the outer surface 40 of the joint portion 38 has a planar shape corresponding to the shoulder portion 34 of the rotary tool 30, and the joint portion 38. The outer surface 40 is higher in the outer diameter direction than the outer surface 36 of the pipe-shaped aluminum member 22 and is lower than the outer surface 42 of the rod-shaped aluminum member 20. In the aluminum members 20 and 22, stepped step portions are formed.
[0021]
Thus, in this embodiment, when the abutting portion 26 is friction stir welded by the rotary tool 30 provided with the pin 32, the shoulder portion 34 of the rotary tool 30 is compared with the rod-shaped aluminum member 20. A pipe-shaped aluminum member that is inferior in strength to the rod-shaped aluminum member 20 from the inside in the radial direction of the outer surface 36 of the pipe-shaped aluminum member 22 that is small in diameter and thin, that is, not to enter the inside of the member. It is effectively prevented that a recess is formed in the outer surface 36 of 22 in the circumferential direction. Therefore, the pipe-like aluminum member 22 is partially thinned at the joint portion 38, and it can be advantageously suppressed that the breaking strength and the fatigue strength are reduced at the thin-walled portion. A bonded product with efficiency can be formed very advantageously.
[0022]
In the present embodiment, the angle between the axis of the rotary tool 30: a and the axis of the rod-shaped aluminum member 20: b (axis of the pipe-shaped aluminum member 22: c): θ ₁ However, since the friction stir welding is performed so as to be a right angle, the angle: θ ₁ Compared to the case where the angle 3 is an acute angle, the shoulder 3 of the rotary tool 30 4 However, contact with the outer surface 36 of the pipe-like aluminum member 22 can be avoided more effectively.
[0023]
In addition, since the friction stir welding is performed in a state where the fitting protrusion 24 of the rod-shaped aluminum member 20 is inserted into the inner hole of the pipe-shaped aluminum member 22, the butt portion 26 of the rotary tool 30 is obtained. It is also possible to advantageously prevent the end of the pipe-like aluminum member 22 from being deformed by the pressing force against.
[0024]
By the way, the method of the present invention is not construed as being limited to the above-described embodiment. FIGS. 8 and 9 show the present invention when friction stir welding pipe-shaped aluminums having different diameters and thicknesses. Another embodiment to which the inventive technique is applied is shown. In FIGS. 8 and 9, members and parts having the same structure as those of the above-described embodiment will be described in detail by giving the same reference numerals as those of the above-described embodiment. The explanation is omitted.
[0025]
That is, as shown in FIG. 8, in order to friction stir weld pipe-shaped aluminum members having different outer diameters, inner diameters, and thicknesses, first, as in the above-described embodiment, two first and second The pipe-like aluminum members 50 and 52 can move relatively in the circumferential direction and the axial direction in a state where the end surfaces of the pipe-like aluminum members 50 are coaxially butted and fitted. It is constrained and held so that it does not exist.
[0026]
Here, the first pipe-shaped aluminum member 50 has a larger outer diameter and a smaller inner diameter than the second pipe-shaped aluminum member 52, so that the wall thickness is equal to that of the second pipe-shaped aluminum member 52. A small diameter cylindrical fitting that can be fitted into the inner hole of the second pipe-like aluminum member 52 by a stepped portion provided on the outer peripheral portion at the front end surface. The protrusion 54 is integrally formed concentrically. Then, by inserting the fitting protrusion 54 into the second pipe-shaped aluminum member 52 until the end surfaces of the first and second members 50 and 52 are abutted with each other, the two members 50 and 52 can be easily positioned coaxially. Further, in the abutting portion 56 of the two members 50 and 52 that are abutted with each other, a stepped portion 58 based on the difference in outer diameter thereof is continuously provided in the circumferential direction over the entire circumference, as in the above embodiment. It will be formed to extend.
[0027]
As in the above-described embodiment, the pin 32 of the rotary tool 30 rotated at high speed is inserted into the abutting portion 56 of the two members 50 and 52, and the two members 50 and 52 are integrally rotated around the axis. As a result, the rotary tool 30 is relatively moved in the circumferential direction along the abutting portion 56, and the abutting portion 56 is friction stir welded in the circumferential direction to form a desired bonded product. However, in the present embodiment, as shown in FIG. 8, the axial center: a ′ of the rotary tool 30 is a butt surface (two halves perpendicular to the axis of the two members 50, 52). From the contact surfaces of the members 50 and 52, in the direction of the second pipe-shaped aluminum member 52, the inclination angle: θ _Three However, the friction stir welding is performed in the inclined form.
[0028]
Specifically, the pin 32 of the rotary tool 30 is inclined at a corner 62 formed by the butt end surface of the first pipe-shaped aluminum member 50 and the outer surface 60 of the second pipe-shaped aluminum member 52. : Θ _Three In this state, the friction stir welding is performed in the circumferential direction in a state where the inclination is maintained, and in this case, the shoulder 34 of the rotary tool 30 is also connected to the second pipe on the thin wall side. The rotary tool 30 and the pin 32 are moved along the corner 62 while the inclination angle of the rotary tool 30 is adjusted so that there is no contact with the outer surface of the aluminum member 52. It will be. As a result, as shown in FIG. 9, a recess is formed in the outer surface 66 of the joint portion 64 so as to be recessed radially inward from the outer surface 60 of the second pipe-shaped aluminum member 52. The thinning of the second pipe-like aluminum member 52 can be extremely effectively prevented, so that a joined product can be obtained in which excellent joint strength and joint efficiency can be advantageously realized. Moreover, in the process of forming such a joint 64, the relief of the fleshed portion of the plasticized butt 56 is the shoulder 3 of the rotary tool 30. 4 Therefore, the outer surface 66 of the joint portion 64 is inclined at the inclination angle θ of the rotary tool 30: θ. _Three Therefore, it is possible to obtain a smooth inclined surface shape having an angle corresponding to the above, and thereby it is possible to ensure a further excellent bonding quality.
[0029]
Further, in the present embodiment, the friction stir welding is performed in a state where the cylindrical fitting protrusion 54 of the first pipe-shaped aluminum member 50 is inserted into the inner hole of the second pipe-shaped aluminum member 52. Therefore, it is possible to advantageously prevent the end of the pipe-shaped aluminum member 22 from being deformed by the pressing force of the rotary tool 30 against the abutting portion 26, and the two pipe-shaped aluminum members 50, 52 can be prevented from being deformed. There is no need to install a backing jig such as a core in the inner hole at the end.
[0030]
The exemplary embodiments of the present invention have been described in detail above. However, the embodiments are merely examples, and the present invention is limited in any way by specific descriptions according to such embodiments. It should be understood that it is not interpreted.
[0031]
For example, in the above-described embodiment, the two aluminum members 20, 22, 50, and 52 that are butted against each other are integrally rotated around the axis, and the rotary tool 30 is relatively moved along the butted portions 26 and 56. However, the aluminum members 20, 22, 50, 52 may be fixed and the rotary tool 30 may be moved in the circumferential direction along the abutting portions 26, 56. Alternatively, the aluminum members 20, 22, 50, 52 may be The rotating tool 30 may be moved in the circumferential direction while being integrally rotated around the axis.
[0032]
In the above-described embodiment, the rod-shaped or pipe-shaped aluminum members 20 and 50 having a large outer diameter and the wall thickness and the pipe-shaped aluminum members 22 and 52 having a small outer diameter and the wall thickness are used. However, the difference between the outer diameters of the members to be joined is not particularly limited, but the thin second surface is formed on the outer surfaces 40 and 66 of the joint portions 38 and 64. It is set appropriately so that a depression lower than the outer surfaces 36 and 60 of the members 22 and 52 cannot be formed, and so that the stirring action of the pin 32 inserted into the butt portions 26 and 56 can be carried out soundly. It will be.
[0033]
Thus, the joined product formed by the method of the present invention can be advantageously used as an automotive part such as an arm member or a subframe member as it is or after being cured by an aging treatment. It will be.
[0034]
In addition, although not listed one by one, the present invention can be implemented in a mode with various changes, modifications, improvements, and the like based on the knowledge of those skilled in the art. It goes without saying that all are included in the scope of the present invention without departing from the spirit of the invention.
[0035]
【Example】
Hereinafter, representative examples of the present invention will be shown to clarify the present invention more specifically, but the present invention is not limited by the description of such examples. It goes without saying.
[0036]
Example 1
First, a rod-like aluminum member (6N01-T1 material) having an outer diameter of 32 mm is prepared as a first member, while a pipe-like aluminum member having an outer diameter of 30 mm and a thickness of 4 mm is prepared as a second member ( 6N01-T1 material) was prepared. Note that a columnar fitting protrusion having a length of 10 mm having a diameter substantially the same as the inner diameter of the second member was integrally formed on one end surface of the first member.
[0037]
Next, the two rod-shaped aluminum members and the pipe-shaped aluminum member thus prepared were abutted coaxially with each other while the fitting protrusions of the rod-shaped aluminum member were inserted into the inner holes of the pipe-shaped aluminum member. Thereafter, the two aluminum members are constrained so as not to move relative to each other at the abutting portion, and in the form as shown in FIG. In such a manner that the axis of the rotary tool is inclined toward the pipe-shaped aluminum member with respect to the contact surface perpendicular to the axis of the two aluminum members, that is, θ in FIG. _Three Is inserted into the butt portion of the two aluminum members so that the angle is 5 °, and the two aluminum members are rotated integrally around the axis, thereby rotating the rotary tool along the butt portion. The rod-like aluminum member and the pipe-like aluminum member were friction stir welded by moving in the direction.
[0038]
In this friction stir welding, a rotating tool having a pin diameter of 3 mm and a pin height of 4.5 mm concentrically provided with a rotating tool shoulder diameter of 10 mm is used, and the rotational speed is used. : 1000 rpm, bonding speed at the outer periphery of 120 mm / min, and an inclination angle (θ ₂ ): 3 ° condition was adopted.
[0039]
And the aging process was performed on the conditions for 185 degreeC and 8 hours with respect to the joining product obtained by this friction stir welding.
[0040]
Then, the bonded product obtained as described above and the pipe-like aluminum member on the thin side which is one of the base materials thereof are respectively compliant with “3. Test method” of JIS-Z-3111-1970. Then, a tensile test was performed by pulling in the axial direction. As a result, the fracture of the joined product occurs in the base material on the pipe-shaped aluminum member side, and the fracture strength (tensile strength) is the same as that of the pipe-shaped aluminum member, and the joint efficiency based on the pipe-shaped aluminum member [= (Joint product Break Breaking strength) / (breaking strength of base material) × 100] was 100%. Moreover, the joint part (bead) is substantially smooth, and when the structure observation of the joint part cross section was carried out, there was no occurrence of a defect such as a dent lower than the outer surface of the pipe-like aluminum member, and it was in a sound joined state. confirmed. In addition, when the fatigue test of the joined product and the pipe-shaped aluminum member was performed according to a conventional method, the fatigue strength of the joined product was substantially the same as the fatigue strength of the pipe-shaped aluminum member.
[0041]
Comparative Example 1
For comparison, a pipe-like aluminum member (6N01-T1 material) similar to that of the first embodiment is prepared as the second member, while the first member is the same as the pipe-like aluminum member. A rod-shaped aluminum member (6N01-T1 material) having a diameter and an outer diameter of 30 mm was prepared. Note that a columnar fitting projection having a length of 10 mm having a diameter substantially the same as the inner diameter of the second member was integrally formed on one end surface of the first member.
[0042]
Then, the two aluminum members were friction stir welded under the same conditions as in Example 1 (however, the axis of the rotary tool was orthogonal to the axis of the two aluminum members) did). Thereafter, an aging treatment was performed under conditions of 185 ° C. and 8 hours to produce a bonded product.
[0043]
And the tension test was implemented by pulling the obtained joining product to the axial direction based on "3. Test method" of JIS-Z-3111-1970. As a result, the fracture of the joined product occurred at the joint, and the joint efficiency based on the pipe-like aluminum member was 92%. Moreover, when the structure | tissue observation of the junction part cross section was implemented, the hollow was produced in the junction part, and it was recognized that the fracture | rupture has arisen from this hollow part. In addition, when a fatigue test of the joined product was performed according to a conventional method, 10 ⁶ Near the rotation, the fatigue strength was only about 10% of the base metal.
[0044]
As is clear from the results of Example 1 and Comparative Example 1, the bonded product formed by the method of the present invention is superior in breaking strength and fatigue strength to those of the comparative example, and is bonded. It can be seen that the strength reduction is avoided very effectively and the same strength as the base material is secured.
[0045]
【The invention's effect】
As is apparent from the above description, according to the method for joining pipe-shaped members according to the present invention, the pipe-shaped member is efficiently bonded to the pipe-shaped or rod-shaped member with excellent bonding strength. As a result, it is possible to ensure a very high joint efficiency.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing an example of a process of friction stir welding a rod-shaped aluminum member and a pipe-shaped aluminum member having the same outer diameter by a conventional method, and (a) shows the two aluminum members Is a cross-sectional explanatory view in a state where the two are abutted, (b) is a right side explanatory view in (a).
FIG. 2 is a partially enlarged cross-sectional explanatory view showing a form of a joint in a joined product obtained by a conventional method.
FIG. 3 is an explanatory view showing an example of a step of friction stir welding of a rod-shaped aluminum member and a pipe-shaped aluminum member according to the method of the present invention, showing a state in which the two aluminum members are butted together.
FIG. 4 is an explanatory view showing another example of a step of friction stir welding of a rod-shaped aluminum member and a pipe-shaped aluminum member according to the method of the present invention, and a pin for a rotary tool is attached to the abutting portion of the two aluminum members. The plugged-in state is shown.
FIG. 5 is an explanatory diagram on the right side surface in FIG. 4;
FIG. 6 is a partially enlarged cross-sectional explanatory view showing the form of the joint in the joined product obtained by the method of the present invention.
FIG. 7 is a front explanatory view showing the form of the periphery of the joint in the joint product obtained by the method of the present invention.
FIG. 8 is an explanatory view showing an example of a step of friction stir welding pipe-shaped aluminum members having different diameters and thicknesses according to the method of the present invention, and corresponds to FIG. 4;
FIG. 9 is a partially enlarged cross-sectional explanatory view showing another form of the joint in the joint product obtained by the method of the present invention, corresponding to FIG. 6;
[Explanation of symbols]
20, 50 First member 22, 52 Second member
24, 54 Mating protrusion 26, 56 Butting part
28, 58 Step part 30 Rotating tool
32 pin 34 shoulder
36,60 second member outer surface
38,64 joint 40,66 outer surface of joint

Claims

A stepped portion is formed on the outer peripheral portion of the end portion of the pipe- shaped first member, and the end portion of the pipe-shaped second member is externally fitted to the small diameter portion of the stepped portion, so that the first and after that it brought together fitted against the second member, on the butt section to the pins provided concentrically at the tip of the rotating tool, insert while rotating integrally with the rotary tool, is relatively moved By friction stir welding such a butt portion, when forming the desired joined product,
As the first member, a member having an outer diameter larger than that of the second member and having a large thickness is used, and the axis of the rotary tool is the shaft of the first and second members. The friction stir welding is performed so that the shoulder portion of the rotary tool does not enter the inside of the member from the outer surface of the second member so as to be orthogonal to the center, and is formed in the butt portion. A pipe-shaped member joining method, wherein a recess lower than the outer surface of the second member is not formed on the outer surface of the joint portion.

A stepped portion is formed on the outer peripheral portion of the end portion of the pipe- shaped first member, and the end portion of the pipe-shaped second member is externally fitted to the small diameter portion of the stepped portion, so that the first and after that it brought together fitted against the second member, on the butt section to the pins provided concentrically at the tip of the rotating tool, insert while rotating integrally with the rotary tool, is relatively moved By friction stir welding such a butt portion, when forming the desired joined product,
As the first member, a member having an outer diameter larger than that of the second member and having a large thickness is used, and the first member is perpendicular to the axis of the first and second members. In a form in which the axis of the rotary tool is inclined to the second member side with respect to the contact surfaces of the first and second members, the shoulder of the rotary tool is the second member. The friction stir welding is performed so as not to enter the inside of the member from the outer surface of the second member, and a recess lower than the outer surface of the second member is not formed on the outer surface of the joint formed in the butt portion. A method for joining pipe-shaped members, characterized in that it is configured as described above.

Lock a stepped portion formed at an end portion outer peripheral portion of the de-shaped first member, relative to the small diameter portion of the stepped portion, and allowed fitted the ends of the pipe-like second member, which after tightening combined fitted against the first and second members, to the butt section, insert the pins provided concentrically at the tip of the rotary tool, while rotating integrally with the rotary tool, relative movement By making the butt portion friction stir welded to form the desired joined product,
As the first member, along with used which have a outer diameter larger made than the second member, such that the axis of the rotary tool is orthogonal to the axis of said first and second members Then, the friction stir welding is performed so that the shoulder portion of the rotary tool does not enter the inside of the member from the outer surface of the second member, and on the outer surface of the joint portion formed in the butt portion, A method for joining pipe-shaped members, wherein a depression lower than the outer surface of the second member is not formed.

Lock a stepped portion formed at an end portion outer peripheral portion of the de-shaped first member, relative to the small diameter portion of the stepped portion, and allowed fitted the ends of the pipe-like second member, which after tightening combined fitted against the first and second members, to the butt section, insert the pins provided concentrically at the tip of the rotary tool, while rotating integrally with the rotary tool, relative movement By making the butt portion friction stir welded to form the desired joined product,
As the first member, along with used which have a outer diameter larger made than the second member, said first and second to be perpendicular to the axis of said first and second members In the form in which the axis of the rotary tool is inclined toward the second member side with respect to the contact surface of the member, the shoulder of the rotary tool is located on the inner side of the outer surface of the second member. The friction stir welding is performed so as not to enter, and a depression lower than the outer surface of the second member is not formed on the outer surface of the joint formed in the butt portion. To join pipe-shaped members.