friction stir welding
JournalofMaterialsProcessingTechnology211 (2011) 972–977
ContentslistsavailableatScienceDirect
JournalofMaterialsProcessing
Technology
journalhomepage:/locate/jmatprote
c
EffectoftooldesignandprocessparametersonpropertiesofAlalloy6016frictionstirspotwelds
W.Yuana,R.S.Mishraa, ,S.Webba,Y.L.Chenb,B.Carlsonb,D.R.Herlingc,G.J.Grantc
a
CenterforFrictionStirProcessing,DepartmentofMaterialsScienceandEngineering,MissouriUniversityofScienceandTechnology,Rolla,MO65409,USAGeneralMotorR&DCenter,Warren,MI48090,USAc
Paci cNorthwestNationalLaboratory,Richland,WA99356,USA
b
articleinfoabstract
Frictionstirspotwelding(FSSW)ofAlalloy6016-T4sheetwasevaluatedusingaconventionalpin(CP)toolandoff-centerfeature(OC)tool.Toolrotationspeedandplungedepthwerevariedtodeterminetheeffectofindividualprocessparameteronlap-shearseparationload.Maximumseparationloadofabout3.3kNwasobtainedbyusinga0.2mmshoulderpenetrationdepthwith1500rpmtoolrotationspeedfortheCPtooland2500rpmfortheOCtool.Threedifferentweldseparationmodesunderlap-shearloadingwereobserved:interfacialseparation,nuggetfractureseparationanduppersheetfractureseparation.Microhardnesspro leforweldcrosssectionindicatednodirectrelationshipbetweenmicrohardnessdistributionandseparationlocations.
© 2010 Elsevier B.V. All rights reserved.
Articlehistory:
Received26July2010
Receivedinrevisedform7December2010Accepted17December2010
Available online 24 December 2010Keywords:
…… 此处隐藏0字 ……
FrictionstirspotweldingTooldesignAlalloy6016
ProcessparameterSeparationmode
1.Introduction
Weightsavingintheautomotiveindustryisbecomingincreas-inglyimportantandcanbeenhancedbyusinglight-weightaluminumalloyforvehicles;particularlyclosurepanelssuchashoods,decklidsandlift-gates.Resistancespotwelding(RSW),currentlythemostcommonlyusedjoiningtechniqueinthevehi-cleindustry,hasapplicationsforlow-carbon,high-strengthandcoatedsteels.However,RSWofaluminumalloysheetsisfraughtwithmanydisadvantages,whichincludeporosityandcracks,asreportedbyThorntonetal.(1996)andGeanetal.(1999).AsevereelectrodetipwearproblemhasalsobeenencounteredduringRSW(Khanetal.,2007).Recently,FSSWforjoiningaluminumalloysheethasbeendevelopedbyMazdaMotorCorporation(Sakanoetal.,2001)andKawasakiHeavyIndustry(Iwashita,2003).
Similartofrictionstirwelding,whichwasdevelopedbyTWI,UKin1991(Thomasetal.,1991),FSSWisasolid-stateweldingtechnique.DuringplungetypeFSSW,arotatingtoolwithaprotrud-ingpinisinsertedintotheoverlappingsheetstoapredetermineddepth.Afteracertaindwelltime,itisretractedandakeyholeisleft.Thefrictionalheatgeneratedatthetool-workpieceinterfacesoftensthesurroundingmaterial,andtherotatingandmovingpincausesthematerial owinboththecircumferentialandtheaxial
Correspondingauthor.Tel.:+15733416361;fax:+15733416934.E-mailaddress:rsmishra@mst.edu(R.S.Mishra).0924-0136/$–seefrontmatter© 2010 Elsevier B.V. All rights reserved.doi:10.1016/j.jmatprotec.2010.12.014
directions(Lathabaietal.,2006).Theinter-mixingoftheplasticizedmaterialandforgingpressureappliedbythetoolshoulderresultintheformationofasolidbondregion(Freeneyetal.,2006).
ThestrengthofweldsiscriticalwhenapplyingFSSWtoload-bearingcomponents.Thisstrengthisaffectedmainlybytoolgeometryandprocessparameters.Toolgeometry,suchasshoul-derdiameterandshape,pinshape,length,diameterandfeatureisakeyparametertoaffectheatgenerationandmaterial ow(MishraandMa,2005).Currently,aconcavetoolshoulderisthemostcommonshoulderdesigninFSSW,thoughsome attoolshoul-derdesignshavealsobeenused.Aruletal.(2005)reportedthatconcaveshouldertoolproducedhigherjointstrengththanthe atshouldertoolduringFSSWofaluminum5754.Badarinarayanetal.(2009a)alsoreportedthatspotweldsmadeusingconcavepro leshoulderexhibitedhigherweldstrengththanthoseusingconvexor atshoulderasaresultofthehighesteffectivetopsheetthick-nessachievedusingconcaveshoulder.Recently,Tozakietal.(2010)proposedanewlydesignedscroll-groovedshouldertoolwithoutaprobewhichproducedmuchhigherfailurestrengthofaluminumalloy6061weldsthantoolwithprobe.Thetoolpinisdesignedtodisruptthefayingsurface,transportandshearadjacentmaterialandgeneratefrictionalheatinthethicksheet.Themostcurrentpindesigninopenliteratureisconventionalcylindricalandconicalpinwithorwithoutthreads.Valantetal.(2005)havereportedathree-pinfeaturedesign.Recently,Mishraetal.(2007)havereportedtheconceptofOCtooltohavebettercontroloverthematerialsweepduringFSSW.Badarinarayanetal.(2009a,b)presentedtheeffectof