简介：

简介：

简介：Anewtypeofnon-preheatedhardfacingelectrodewasdevelopedusingH08Aasthecoreandthecoatcontentsincludingferrotitanium,ferrovanadium,graphite,rutileetc.Themicrostructuresandpropertiesofhardfacingmetalweresystematicallyresearched.Theresultsshowthehardnessofhardfacingmetalincreaseswithincreasingofferrotitanium,ferrovanadium,graphiteinthecoat,butthecrackresistanceandprocessingweldabilitybecomeworse.Thecarbidesformedbyarcmetallurgicreactionareuniformlydispersedinthematrixstructure.Thephasesofhardfacingmetalconsistofα-Fe,γ-Fe,VC,TiCandFe3C.ThecarbidesarecompressionaggregationofTiCandVC,andtheirappearancespresentirregularblock.Thematrixmicrostructureofhardfacingmetalislathmartensite.Thehardfacinglayerswithbettercrackresistanceandwearabilityareachievedandnovisiblecracksoccurwhenusingnon-preheatedelectrodeincontinuousweldingprocess.Hardnessofhardfacingmetalismorethan60HRC,anditsrelativewearabilityisfivetimesofwearabilityofD667electrodeinabrasiveweartest.

简介：

简介：SolderingofLD31aluminumalloysusingSn-PbsolderpasteafterelectricbrushplatingNiandCucoatingswasnvestigated.ThetechnologyofelectricbrushplatingNiandCuwasstudiedandplatingsolutionwasdeveloped.Themicrostructureofthecoatings,solderedjointandfracturefacewereanalyzedusingopticmicroscopy,SEMandEDX.Theshearstrengthofsolderedjointcouldreachashighas26.83MPa.Theresultsshowedthatreliablesolderedjointcouldbeobtainedat230℃,theadhesionofcoatingsandLD31aluminumalloysubstratewashighenoughtobearthethermalprocessinthesoldering.

简介：MagneticBarkhausennoise(MBN)isaphenomenonofelectromagneticenergyduetothemovementofmagneticdomainwallsinsideferromagneticmaterialswhentheyarelocallymagnetizedbyanalternatingmagneticfields.AccordingtoFaraday’slawofelectromagneticinduction,thenoisecanbereceivedbythecoilattachedtothesurfaceofthematerialbeingmagnetizedandthenoisecarriesthemessageofthecharacteristicsofthematerialsuchasstresses,hardness,phasecontent,etc.Basedonthecharacteristicofthenoise,researchingabouttherelationshipbetweentheresidualstressintheweldingassemblyandthenoisearecarriedout.Furthermore,dataprocessisperformedbyRMS(RootMeanSquare)equationandPowerSpectrumanalysis.

简介：

简介：

简介：Anaxisymmetricfiniteelementmodelisdevelopedtosimulatethetemperaturefieldofresistantspotweldingaccordingtotheprocesscharactersofnuggetformationofnon-equalstainlesssteelsheets.Asimulationmethodoftheinteractionofelectricalandthermalfactorsispresented.Thespotweldingprocessofnuggetformationissimulatedusinghardandsoftweldingtechniquenorms.Theheatingcharactersofsoftandhardnormsdeterminethedifferencesintheprocessofnuggetformationanddeterminethefinallyshapeandoffsetofnugget.Experimentalverificationshowsthatthemodelpredictionagreeswellwiththepractical.

简介：Metallurgicalmodelingofsynergisticmicrocrackself-repairmenduringweldingsinglecrystalandpolycrystallinesuperalloysofhigh-temperatureaerospacematerialshasbeenproperlyestablished.Theideaofimprovementofnickel-basedsuperalloysweldabilitythroughnon-equilibriumsolidificationbehaviorofbackfilltoself-repairarterialcracknetworkisusefullyproposed.Crystallographiccontrolstrategyofcrackself-repairmenoffusionzoneinterdendriticsolidificationcrackingandheat-affectedzone(HAZ)intergranularliquationcrackingistechnicallyachievable,indicatingthatoptimalniobiumalloyingbeneficiallyrefinesweldmicrostructure,stabilizestheprimarysolidificationpath,increasesthesolidificationtemperatureandconcomitantlydecreasestheweldpoolgeometry.High-carbongrainboundaryismorethermalstableandlesscontributestoincipientintergranularliquidfilmthanthatoflow-carbongrainboundary.Thetheoreticalpredictionsofcrackingsusceptibilityareindirectlyverifiedinarathersatisfactorymanner.Additionally,themetallurgicalmodelingenhancespredicativecapabilitiesandtherebyisreadilyapplicableforotheralloysystems.