简介：Thispaperpresentsamicrostructuralcharacterizationofstandardferroniobium(FeNb)andastudyofitsdissolutioninsteel.Interrupteddissolutiontrialsatdifferenttemperatureswerecarriedoutinalaboratoryinductionfurnace.ThemicrostructureattheinterfacebetweensolidFeNbandfrozensteelwasanalyzedandcomparedwiththeoriginalFeNbparticles.TheresultsallowedclarifyingboththeFeNbdissolutionmechanismanditsincorporationkineticsatsteelmakingtemperatures.ExperimentalresultsfromthedissolutionofstandardFeNbinliquidsteelprovedthatthedissolutionratesofFeNbparticleswerehigherthanthosereportedinthepertinentliterature,wheremodelsassumethatFeNbdissolvesonlybythediffusionofsolidparticlesduetoitshighmeltingtemperatures(over1600℃).MostrecentFeNbphasediagramsandDTAanalyseshaveshownthatstandardFeNbbeginstomeltdownbelow1600℃.TheexperimentalevidencesinthisworkhaveledtotheadoptionofanewdescriptionofthedissolutionmechanismwherebystandardFeNbdissolvespredominantlybythemeltingofitseutecticzonesat1500℃to1510℃and,lateron,bythemeltingoftheprimarylathsbetween1530℃and1575℃,i.e.,belowthesteelmakingtemperaturesofaround1600℃.Basedontheseresultsandonpreviousmelting-shopexperience,thispaperrecommendsthebestpracticesfortheadditionofFeNbduringthemicroalloyedsteelssecondaryrefiningphase.