反应釜毕业设计外文翻译Word下载.docx
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TwosquaretubesaremadeofA356bysandcastingandthenmachined.TheyareassembledbyfourMIGwelds,namedW1toW4.TheirdimensionsandtheweldingconfigurationaredepictedinFigure1.Bothsmall(inner)andlarge(outer)tubesarewellpositionedonafixtureusingv-blocksasshowninFigure2.Thedimensionsofthetubesmakeaperipheralgapof1mmbetweenthem.Thisfixtureisfixedonapositionerthatallowstheweldingprocesstobecarriedoutalwaysinthehorizontalposition.Thelengthofeachweldisof35mm.TheFroniusweldinghead,whichismountedonaMotomanrobot,wasusedfortheMIGweldingprocess.Table1indicatestheparametersoftheweldingprocessforthisweldingconfiguration.
Table1:
MIGweldingparameters.
Voltage
Amperage
Speed
Thick1
Thick2
Gap
(V)
(A)
(m/min.)
(mm)
23
260
1.25
4
1
a)
b)
Figure1:
Tubeweldingconfiguration:
a)cross-sectionview,b)tubedimensions
Figure2:
Experimentalsetupfortubewelding
Testing
TheporosityofweldswasobservedbeforeandafterweldingusingtheX-raytechniquetocheckthequalityoftheseweldsaccordingtothestandardASTME155.ThewholeweldedtubeswerethentestedbytractiononaMTStestingmachine.ThefinaldimensionsoftheweldedtubesaremeasuredonaCMMmachineatmanypointsonthetubes.Thedistortionoftheweldedtubesisdeterminedbycomparingthefinalpositionswiththeinitialpositionsofthetubes.
Numericalanalysis
InSysweld,aweldinganalysisisperformedbasedonaweak-couplingformulationbetweentheheattransferandmechanicalproblems.Onlythethermalhistorywillaffectonthemechanicalproperties,butnotinreversedirection.Therefore,athermalmetallurgicalmechanicalanalysisisdividedintotwosteps.Thefirststepisathermalmetallurgicalanalysis,inwhichtheheattransferredfromtheweldingsourcemakesphasechangesduringtheweldingprocess.Theresultsoftemperatureandphasechangesfromthefirststeparethenusedasinputforthesecondanalysis.Itisapurethermo-elasto-plasticsimulation[6].
Heatsourcemodelidentification
Beforerunningaweldingsimulation,itisnecessarytodeterminetheparametersoftheheatsourcemodel.Thisiscalledheatsourcefitting.Actually,itisathermalsimulationusingthisheatsourcemodelinthesteadystate,whichiscombinedwithanoptimizationtooltoobtaintheparametersoftheheatsource.Figure3presentstheformofa3DconicalheatsourceofwhichtheenergydistributionisdescribedinEq
(1)asfollows:
F=Q0exp(-r²
/r0²
)
(1)
inwhichQ0denotesthepowerdensity;
andr,r0aredefinedby
r²
=(x-x0)²
+(x-x0-vt)²
(2)
and
r0=re-(re-ri)(ze-z+z0)/(ze-zi)(3)
where(x0,y0,z0)istheoriginofthelocalcoordinatesystemoftheheatsource;
reandritheradiusoftheheatsourceatthepositionszeandzi,respectively;
vtheweldingspeedandtthetime.
Inthisstudy,ametallographiccross-sectionhasbeenusedtoidentifytheheatsourceparametersasshowninFigure4.Theuseofa3Dconicalheatsourcefitsverywelltheweldcross-section.Themeshsizeinthecross-sectionisaround0.5mmforthiscase.Thefineristhemesh,themoreaccurateistheshapeofthemeltingpool,butthelongeristhesimulation.
Figure3:
3Dconicalheatsource(Sysweld).
Figure4:
(a)Metallographiccross-section,(b)Meltingpoolcross-section.
Analysismodel
ThemeshofthetubeswascreatedinHypermesh7.0.Sysweld2007hasbeenusedassolverandpre/postprocessor.Afull3Dthermalmetallurgicalmechanicalanalysiswithbrickandprismelements.TwoweldingsequenceshavebeendonesuchasW1/W2/W3/W4andW1/W3/W2/W4.Thetubesareclampedusingfourv-blocksduringthewelding,twoforeachtube.Inthesimulations,thepositionswherethetubesareincontactagainstthesurfacesofthev-blocksareconsideredasfixedconditions(i.e.Ux=Uy=Uz=0).Inthereleasephase,thetubesarefreefromthev-blocks.
Results
Thedistortionoftheweldedtubeismeasuredwhenitisreleasedfromtheconstraints.Thedistortionisdeterminedbymeasuringthedisplacementofthesmalltubeonthetopandlateralsurfacesalongthecentrelineofthetube.Thesemeasuresarerelativetothelargetube.Figures5a-bdepictthedistortionpredictedbythenumericalsimulationsofthesequenceW1/W2/W3/W4andW1/W3/2/W4,respectively.GoodagreementsbetweenexperimentalandnumericalresultswereobtainedinthetwoweldingsequencesasindicatedinTables2-3,inboththedistortiontendencyanddistortionrangeoftheprocessvariation.
Figure5:
Tubedistortion(NormU):
(a)SequenceW1/W2/W3/W4,(b)SequenceW1/W3/W2/W4.
Table2:
Distortionresultcomparison(weldingsequenceW1/W2/W3/W4)
Displacements(mm)
Uy
Uz
Experimrntal
From-0.4to-0.59
From-0.35to-0.51
3Dsimulation
-0.4
-0.51
Table3:
Distortionresultcomparison(weldingsequenceW1/W3/W2/W4)
Displacements(mm)
From-0.07to-0.11
From-0.12to-0.21
-0.05
-0.26
Figure7:
StateofstressesSxy(a)Clamped,(b)Released.(Red=positive,Blue=negative)
Figure8:
StateofstressesSxz(a)Clamped,(b)Released.(Red=positive,Blue=negative)
Figures6-8showsthestateofthestressesoftheweldedtubesatroomtemperatureforthesequenceW1/W2/W3/W4afterweldingwhenclampledandreleasedfromconstraints(xisthedirectionalongtheaxeoftheweldedtube).Toshowhowtheweldedtubeisdistorted,positive-negativevaluesareusedinsteadofthetruevaluesofstresses.Thedistortionoftheweldedtubecanbeexplainedasthenewequilibriumpositionduetotheresidualstresseswhenthereisnoexternalload.Itisremarkedthatinthepresenceoflargegaps,thedistortionoftheweldedtubeisverylikelyintherotationalmodearoundlocalwelds.
Conclusions
TheMIGweldingisverygoodforassemblingaluminiumcasttubes(hollowparts)inthepresenceoflargegaps.
The3DthermalmetallurgicalmechanicalsimulationofthecasttubeweldingusingSysweldhasbeenvalidated.Averygoodagreementbetweennumericalandexperimentalresultswasobtainedforboththedistortiontendencyanddistortionrange.
Theweldingsequencehasamajorinfluenceonthedistortionoftheweldedstructure.Itturnsoutthattheoptimizationoftheweldingsequencesforareasonabledistortionofaweldedstructurewithalargenumberofweldsbecomesveryimportant.
Acknowledgments
TheauthorswouldliketothankgratefullyRioTintoAlcanandGeneralMotorforfinancialandtechnicalsupports,particularlyMartinFortierandPei-ChungWang.Also,theauthorsaregratefultoWeldingTeamatATC(AudreyBoily,MartinLarouche,Franç
oisNadeauandMarioPatry)forexperimentalworks.
References
1.K-H.VonZengen,Aluminiuminfuturecars–Achallengeformaterialsscience,MaterialsScienceForum,519-521(Part2),1201-1208(2006).
2.S.WiesnerS.,M.RethmeierandH.Wohlfart,MIGandlaserweldingofaluminiumalloypressurediecastpartswithwroughtprofiles,WeldingInternational,19
(2),130-133(2005).
3.R.Akhter,L.Ivanchev,C.V.Rooyen,P.KazadiandH.P.Burger,LaserweldingofSSMCastA356aluminiumalloyprocessedwithCSIR-Rheotechnology,SolidStatePhenomena,116-117,173-176(2006).
4.J.F.Lancaster,Metallurgyofwelding,AbingtonPublishing(1999).
5.Φ.Grong,Metallurgicalmodellingofwelding,Theinstituteofmaterials(1997).
6.Sysweld,Sysweldreferencemanual,ESIGroup(2005).
译文
铸造A356铝合金的焊接模拟
X-T.Pham*,P.GougeonandF-O.Gagnon
摘要:
空心铝铸造件的焊接是一个很有前途的新结构组件技术的趋势。
然而,组件之间的差距较大,焊接孔隙度,大变形和热裂需要处理的风险。
在这篇文章中,对铸造A356铝合金的方管的MIG焊接进行了研究。
并对焊接管弯曲变形进行了数值模拟预测。
实验结果和数值模拟结果的相似度很高。
1前言:
由于铝合金结构自身的重量轻,所以它变得越来越流行,尤其是在汽车制造业。
此外,空心铝铸造件的焊接是一种新的有前途的结构