The growing demand for energy, the significant increases in prices offossil fuels and the environmental commitments have led ACESITA toreview its current energy sources and to aim at self-sufficiency in renewableenergy. ACESITA operates two blast furnaces with coke or charcoalas reductant. With the recent investments in the ironmaking areaand in Acesita Energética, and with the combined mastering of blastfurnace operation and charcoal production, ACESITA will be prepared,as of 2009, to operate its blast furnaces with 100% renewable fuel(charcoal). Forest based charcoal production through a modern, environmentally,socially and economically sustainable way is demonstrated.

Flameless oxyfuel combustion used in industrial furnaces gives a uniformtemperature and heat flux distribution along with high availableheat. NOx emissions can be maintained at extremely low levels, meetingthe most demanding environmental regulations. Since 2003 theexperimental results from flameless oxyfuel technology have been provenin industrial installations such as reheating and annealing furnacesas well in ladle preheating stations.

The most significant developments the electric furnace has benefitedfrom over the last decade are presented. The new technologies havemade it possible to improve productivity and to reduce productioncosts. The advantages offered by the electric furnace in the EU pertainto four main issues: costs, organisation, customer service and environmentalregulations. The evolution of electric steel production in the EUand in the world is discussed.

Virtual sensors allow the measuring of variables for which no physicalsensor is available using indirect measurements of related variables.In this work we describe the implementation of a virtual sensor for thezinc coating thickness in a hot dip galvanizing line from related processvariables such as blowing pressure, knives-to-strip distance, knives-topotdistance, etc., based on artificial neural networks that model nonlineardynamical relationships. The virtual sensor is currently working onAvilés Galvanizing 2.

More stringent customer requirements and productivity give steelmakers an incentive to deliver higher surface quality strips. To controland to improve the surface properties, CRM has developed a sensorgrabbing highly magnified images of a moving product. The chosenmethod is based on the principle of triangulation: a very thin line is projected on the surface and the relief is calculated by the analysis of linedeformation. The result is an on-line 3D analysis sensor for assessing topography.

Critical parameters that affect both the ferrite grain size and the precipitation kinetics during hot rolling Nb-bearing steel were studied.Accelerated cooling was applied after the last pass of finishing rolling.In all cases the Nb(C,N) precipitation was strongly retarded, increasingthe precipitation hardening by the formation of fine precipitates.Moreover a non-negligible amount of Nb remained in solution. Nb(C,N)precipitation occurred during annealing cold rolled steel, causingsecondary hardening.

With increasing boron content, the coarsening rate of M23C6 carbidesbecomes reduced near grain boundaries in tempered martensitic 9Cr-3W-3Co-VNb steel during creep at 650 °C. This retards the recovery ofmartensitic microstructure up to long times and increases long-termcreep strength. However, excess addition of boron and nitrogen causesthe formation of large amount of massive boron-nitrides during normalizingat 1050-1150 °C, which significantly decreases the boronconcentration available for microstructure stabilization and degradesthe creep strength.