The growing demand for energy, the significant increases in prices of fossil fuels and the environmental commitments have led ACESITA to review its current energy sources and to aim at self-sufficiency in renewable energy. ACESITA operates two blast furnaces with coke or charcoal as reductant. With the recent investments in the ironmaking area and in Acesita Energética, and with the combined mastering of blast furnace 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 uniform temperature and heat flux distribution along with high available heat. NOx emissions can be maintained at extremely low levels, meeting the most demanding environmental regulations. Since 2003 the experimental results from flameless oxyfuel technology have been proven in industrial installations such as reheating and annealing furnaces as well in ladle preheating stations.

The most significant developments the electric furnace has benefited from over the last decade are presented. The new technologies have made it possible to improve productivity and to reduce production costs. The advantages offered by the electric furnace in the EU pertain to four main issues: costs, organisation, customer service and environmental regulations. The evolution of electric steel production in the EU and in the world is discussed.

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

More stringent customer requirements and productivity give steel makers an incentive to deliver higher surface quality strips. To control and to improve the surface properties, CRM has developed a sensor grabbing highly magnified images of a moving product. The chosen method 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 line deformation. 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, increasing the 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, causing secondary hardening.

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