The development of steel refining operations at ArcelorMittal
FCWE for the production of ULS steels is reported. Several plants with different equipments produce grades with S <30 ppm, thus permitting to identify the most efficient process, from hot metal desulfurization to secondary metallurgy. For sites producing steels with S <30 ppm, four secondary metallurgy routes coexist in ArcelorMittal FCWE. The Vacuum Tank Degasser makes it possible to reach very low S and N contents simultaneously. To face the increase of the share of Ultra Low Sulfur products, it is necessary to further enhance the kinetics of desulfurization by steel - slag stirring at the atmospheric pressure.