The development of steel refining operations at ArcelorMittalFCWE 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.

The Stefana Bar Mill (Nave, Brescia, Italy) was commissionedin April 2008. The production rate, on a 3-shift basis is750,000 t/y. The product mix includes straight rebars from8 mm to 40 mm diameters and compact coils from 8 mmto 16 mm diameters. The salient features of this plant arestrictly related to improvement of profitability on low-addedvalue products, concentrating on efficiency and throughputoptimization.

The ArcelorMittal's hot dip galvanizing line at Florangedeveloped and commissioned its own coating weight controlsystem. This system actuates the pressure as well as theposition of the knives. The fast and accurate response toupsets is partly attributed to the continuous auto-adaptationof the knife-to-strip distance. Large and rapid benefits, i.e.quality improvement and zinc savings, have been takenimmediately after it was put into production.

Une innovation majeure est apportée parl’utilisation de gyroscopes laser. PARALIGN®est le premier appareil au monde à utilisercette technique, appelée mesure par inertie,permettant de calculer précisément la positionrelative des rouleaux dans l’espace, sans viséeoptique, sans ligne laser à installer le long dela machine.

A critical evaluation is reported of the features andproperties of thick ferrules (2.25%Cr-1%Mo steel)realized through different technological routes: forging,hot rolling and cold bending. The characterization ofthe ferrules has been performed with metallographicobservations, mechanical tests and texture crystallographicanalysis by SEM-EBSD. The results show the effect ofthe various processes on mechanical performance andhighlight the associated microstructural modifications theybring about.

Le projet PREDIT CRISFIS (financé parl’ADEME) consiste à étudier conjointementles aspects crissement et fissurationdes freins à disques haute puissancepour le ferroviaire. Dans cet article,les avancées concernant la partie fissurationsont abordées. Une démarche expérimentaleet de modélisation est adoptée dans le butde mieux comprendre la fissurationdes disques. Des essais de freinage réaliséssur banc d’essai industriel à l’échelle 1sont présentés. Dans un premier temps,l’influence du type de garniture surle chargement thermique vu par le disqueest étudiée au moyen d’une camérade thermographie infrarougeet de thermocouples implantés dansles garnitures et dans le disque de frein.Dans un deuxième temps, les chargementsthermiques extraits des filmsthermographiques sont utilisés commedonnées d’entrée pour des calculsthermomécaniques. Enfin, les résultatsdes modélisations et des essais sont corrélésaux endommagements observéssur les disques.