有关高强镀锌钢激光填粉焊接的粉末输送研究pdf

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1、学兔兔www.xuetutu.com第50卷第4期机械工程学报VO1．50NO．42014年2月JOURNALOFMECHANICALENGINEERINGFeb．2014DoI：lO．3901／JME．2014．04．060高强镀锌钢激光填粉焊接的粉末输送研究水张屹徐磊刘西霞李庆福(湖南大学汽车车身先进设计制造国家重点实验室长沙410082)摘要：激光填粉焊接是一种高柔性化焊接加工技术，能有效降低激光焊接装配精度。使用自行开发的侧向送粉装置，基于粉末分布密度与图像灰度的相关性，测量分析粉束截面的粉末

2、分布密度和粉末输送的有效性，并开展高强镀锌钢光纤激光填粉焊接的焊接工艺性及接头性能的研究。结果表明，粉末落点是决定粉末利用率的关键因素。以45o侧向送粉时，有效输送率最高的粉末落点为一1．75nllTl。粉末落点过于靠近或远离激光束时均不利于金属粉末有效熔入熔池。粉末落点为-4mm时，粉末利用率最高。焊缝中心铜的质量分数随着送粉速度的降低而线性减小。填充粉末能明显提高焊缝表面质量，细化热影响区晶粒，提高焊缝组织性能，同时提高了激光焊接间隙裕度，降低工件对激光焊接装配精度的要求。关键词：激光焊接；粉末输

3、送；添加粉末；装配精度中图分类号：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