简介：Thetransformationinducedplasticity(TRIP)steelseffectoccursbecauseofthemartensitictransformationofretainedausteniteduringplasticdeformation,anditprovidesthesteelwithexcellentstrengthandductility.Whileweldingremainsavitalpartofautobodymanufacturing,theweldabilityofTRIPsteelsisproblematic,andthispreventsitsadoptionformanyapplicationsintheautomotiveindustry.Thispresentworkstudiestheeffectsofweldingandpost-weldheattreatmentonthemicrostructureof...

简介：Themicrostructuresandprecipitatesinbasemetalsandheataffectedzones(HAZs)oftwoZr-Bmicroalloyedsteelswerecharacterizedbymeansofopticalmicroscopy(OM),transmissionelectronmicroscopy(TEM)andenergydispersivespectrum(EDS).Ithasbeenfoundthatprecipitatesoftensofnanometersinsizearepresentinthebasemetalsofbothsteels.Theaverageparticlesize,however,intheZr-BsteelwithTiislargerthanthatinthesteelwithoutTi.Afterthermalsimulations,inbothcases,theMnSsulfidescannucleateoncubic(Nb,Ti)(C,N)carbonitridesandnearlysphericalZr-bearingcompounds.TheprecipitatesintheHAZsofbothsteelsarecoarserthanthoseinthebasemetals,intherangesof150-200nmand50-100nmforTiaddedandTi-freesteels,respectively.

简介：ToresearchtheeffectofZradditiononinhibitingaustenitegraingrowthofTi-bearinglowcarbonsteels,twosteelswithdifferentZrcontentswerepreparedusingalaboratoryvacuuminductionfurnace.TheperformanceofHAZunderweldthermalsimulationswasinvestigated.Theimpacttoughness,microstructureandthesecond-phaseparticleperformanceofHAZunderweldthermalsimulationswereinvestigated.TheHAZtoughnesswasimprovedfrom13Jto87Jbyadditionof0.010%Zrintothesteel,withthefracturemechanismchangingfromcleavagefracturetotoughnessfracture,whichwasmainlyattributedtothesecond-phaseparticlesthatwerepotenttonucleateacicularferriteinHAZduringwelding.Itwasconcludedthatthesecond-phaseparticlesTiOx+MnS,ZrO2+MnSorTiOx+ZrO2+MnSwerenucleatedonZrO2orTiOx(x=1.5,2).Thismethodcanbeappliedtograinrefinementbypromotingtheacicularferriteformationandgrowthduringlarge-scalewelding,asinthecasesofthicksteelplatesrequiringhigherheatinputsduringwelding.