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1、華中科技大學(xué)碩士學(xué)位論文摘要激光—電弧復(fù)合焊接是一種新興的特種激光加工技術(shù),它將兩種物理性質(zhì)、能量傳輸機(jī)制截然不同的激光和電弧熱源復(fù)合在一起,同時(shí)作用于同一加工位置,既充分發(fā)揮了兩種熱源各自的優(yōu)勢(shì),又相互彌補(bǔ)了各自的不足,從而形成了一種全新高效的熱源。激光—電弧復(fù)合熱源至少是一種激光熱源(CO2、YAG等)與一種弧焊熱源(TIG、Plasma、MIG/MAG)的組合,激光—MIG復(fù)合熱源因其焊接效率高、間隙適應(yīng)性好、焊縫成分和性能可控等優(yōu)點(diǎn)正在成為工業(yè)生產(chǎn)中最重要的激光焊接方法之一。本文在總結(jié)國內(nèi)外激光—電弧復(fù)合熱源焊接研究現(xiàn)狀基礎(chǔ)上,對(duì)激光—MIG復(fù)合
2、焊接技術(shù)進(jìn)行了工藝基礎(chǔ)及應(yīng)用的研究。首先建立了CO2激光—MIG電弧旁軸復(fù)合熱源系統(tǒng),以普通碳鋼為試材進(jìn)行了堆焊試驗(yàn),對(duì)焊縫的橫斷面幾何形貌進(jìn)行了測(cè)定,結(jié)果顯示,復(fù)合焊較激光、電弧焊的熔深、熔寬增加,焊縫成型更美觀,復(fù)合激光功率越大,作用效果越明顯。隨后利用Nd:YAG激光—MIG電弧復(fù)合熱源系統(tǒng)對(duì)激光功率、電弧功率、焊接速度、焊接方向等參數(shù)與焊縫形貌之間的關(guān)系進(jìn)行了研究,討論了激光與電弧的交互作用。研究表明:在一定的焊接工藝條件下,激光功率主要影響復(fù)合焊縫熔深,而電弧功率主要影響熔寬,激光電弧的交互作用有利于增加熔深,卻負(fù)作用于熔寬的增加;當(dāng)一定功率的
3、Nd:YAG激光與電弧熱源復(fù)合時(shí),焊縫熔深隨著電弧功率的增大先增后減,熔深最大時(shí),電弧功率與復(fù)合熱源功率的比值約為0.6。對(duì)應(yīng)的其它實(shí)驗(yàn)結(jié)果也表明:復(fù)合熱源焊接效率提高,焊前適應(yīng)性好。最后,將激光—MIG復(fù)合焊接技術(shù)應(yīng)用于ZL114鋁合金的焊接,成功地實(shí)現(xiàn)了2mm和8mm厚平板及筒體復(fù)合熱源的拼焊。關(guān)鍵詞:激光—MIG復(fù)合焊接激光加工Nd:YAG激光電弧功率焊縫形貌鋁合金I華中科技大學(xué)碩士學(xué)位論文AbstractLaser–archybridweldingisanewspecialweldingtechniqueinlaserprocessing,inw
4、hichthelaserbeamandthearcactonthesamemoltenpool,thesynergisticactionsofthelaserandthearcwereexploited,improvingtheweldingefficiencycomparedwiththeindividualprocesses.Adescriptivetermoflaser–arcprocessesshouldincludethelasertype(i.e.CO2,Nd:YAG)andthearcweldingprocess(TIG,Plasma,MI
5、G/MAG),andhybridlaser–MIGweldingbecomesoneofthemostsignificantlaserweldingtechnologiesinindustryduetoitshigherweldingefficiency,highertolerancetogapsbetweenplates,andadjustmentofcompositionandmicrostrctureoftheweldmetal.Basedonsummarizationofthecurrentresearchonhybridweldingtechn
6、ique,aprogramofexperimentalworkwasundertakentoinvestigatethehybridlaser–MIGweldingprocessanditsapplicationinthispaper.FirstaparaxialCO2laser–MIGhybridweldingsystemwassetupandproducedbead–on–platerunsoncarbonsteelunderdifferentweldingconditions,theweldbeadshapeweremeasured.Theresu
7、ltsshowthatthelaser–MIGhybridweldingcanincreasepenetrationandwidth,improvethequalityofweldbeadformationcomparedwithlaserandarcwelding,andthehigherthelaserpower,themoresignificanttheeffect.ThenaNd:YAGlaser–MIGhybridweldingsystemwasusedtostudytherelationshipbetweenhybridweldingpara
8、metersandbeadgeometry,theparameterslikel