Small-angleneutronscattering(SANS)andenergy-filteredtransmissionelectronmicroscopy(EFTEM)wereemployedtocharacterisetheprecipitationbehaviourinthehigh-speedsteelHS6-5-2duringtempering.WithSANStheevolutionofthesizedistributionofprecipitatesduringisothermaltemperingat590#9702;Cwasinvestigated.TheSANSresultsarediscussedassumingthatthreepopulationsofprecipitatescanbedistinguishedduringtemperingat590#9702;C.Thesmallestpopulationwith