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1、學兔兔www.xuetutu.com第50卷第4期機械工程學報VO1．50NO．42014年2月JOURNALOFMECHANICALENGINEERINGFeb．2014DoI：lO．3901／JME．2014．04．060高強鍍鋅鋼激光填粉焊接的粉末輸送研究水張屹徐磊劉西霞李慶福(湖南大學汽車車身先進設計制造國家重點實驗室長沙410082)摘要：激光填粉焊接是一種高柔性化焊接加工技術，能有效降低激光焊接裝配精度。使用自行開發(fā)的側向送粉裝置，基于粉末分布密度與圖像灰度的相關性，測量分析粉束截面的粉末
2、分布密度和粉末輸送的有效性，并開展高強鍍鋅鋼光纖激光填粉焊接的焊接工藝性及接頭性能的研究。結果表明，粉末落點是決定粉末利用率的關鍵因素。以45o側向送粉時，有效輸送率最高的粉末落點為一1．75nllTl。粉末落點過于靠近或遠離激光束時均不利于金屬粉末有效熔入熔池。粉末落點為-4mm時，粉末利用率最高。焊縫中心銅的質量分數隨著送粉速度的降低而線性減小。填充粉末能明顯提高焊縫表面質量，細化熱影響區(qū)晶粒，提高焊縫組織性能，同時提高了激光焊接間隙裕度，降低工件對激光焊接裝配精度的要求。關鍵詞：激光焊接；粉末輸
3、送；添加粉末；裝配精度中圖分類號：TG456StudyonPowderDeliveryinLaserWeldingofHighStrengthGalvanizedSteelwithPowderFillingZHANGYiXULeiLIUXixiaLIQingfu(StateKeyLaboratoryofAdvancedDesignandManufacturingforVehicleBody,HunanUniversity,Changsha410082)Abstract：Laserweldingwith
4、powderfillingisahighlyflexibleweldingtechnologyduetoitsefectivereductionoftheassemblyaccuracyofworkpiece．Basedonthecorrelationbetweenthedensityofpowderdistributionandtheimagegray,thedistributiondensityonthecrosssectionofthepowderbeamismeasured，andtheefe
5、ctivenessofthepowderdeliverywithaself-developedlateraldeviceforpowderfeedingisanalyzed．Furthermore，theweldingtechnologicalpropertiesandthejointperformanceinfiberlaserweldingofhighstrengthgalvanizedsteelwithpowderfillingarestudied．Theresultsshowthat：Thep
6、owderpositionisthekeyfactoroftherateofthepowderutilization．Whenfillingpowderlaterallyinangleof45。，themostefectivedeliveryratecanbeobtainedwiththepowderpositionof-1．75i／lln．Thepowerwouldtobefedintotheweldingpoolinefectivelywhenpowderpositionistooclosetoo
7、rfarawayfromthelaserbeam．ThehighestrateofthepowderutilizationCanberealizedwiththepowderpositionof--4mm．Thecoppercontentontheweldcentersectiondecreaseslinearlywiththereductionofthepowderfeedingspeed．Powderfillingcansignificantlyimprovetheperformanceofthe
8、weldsurfaceandrefinethegrainsintheheat—afectedzone，aswellastheimprovementoftheweldproperties．Laserweldingwithpowderinjectionisabletoimprovetheweldsurfacequality,createfinermicrostructureintheheatafectedzone，improvethestrengthofth
