A comparative study between the mineral coals used byArcelorMittal Tubarão has been carried out, aiming atdetermining complementing criteria to the current energy modelfor the mineral coals purchasing qualification used for injectionin the blast furnace. Material characterization techniques wereemployed allowing the mapping of the characteristics of thecoals which potentially affect the stability of the pig ironproduction process.


Solid and liquid iron oxides exhibit characteristics ofsemiconductors. The semiconductive behavior also featuresin some slags containing iron oxide. This paper aims athighlighting some of the experimental indications of the roleof semiconductivity in electrical conduction, the chemicaldiffusion and in reaction kinetics at slag surfaces. It is nota thorough review of the subject matter but an attemptat shedding some light on the connection between theseproperties.

The development of new highly sophisticated steelgrades with extreme demands on cleanness requiresaccurate refining. The paper gives an overview on thestate-of-the-art in secondary metallurgy and describesthe trends in secondary metallurgy research in Germany.

UST rejection ratio of heavy plates was relatively high sincethe 300 mm thickness slab caster has been operated atPohang Works. An internal quality prediction system for slabwas developed that can evaluate the center segregationlevel of slabs within 5 minutes after cutting. The rejectionratio of heavy plate thicker than 70 mm could be reducedeffectively from 5% down to below 0.5% by applying thistechnology.

A new automated system installed in the ArcelorMittal Asturiassteel plant in Avilés, based on novel image treatment, aimsat performing an on-line inspection, with feed-back to theprocess, verifying the effectiveness of scarfing. It detectsremaining defects as well as new ones introduced by thisoperation, thus allowing a quick and reliable assessment offinal surface quality.

The relationship between water quality management andthe total cost of operation of the steel mill are normallyunderestimated as areas of relevant cost reduction andproductivity improvements.The work that was accomplished on cooling water systemsassociated with n°4 slab caster at CSN from 2004 toincrease significantly steel plant productivity and reduce thetotal cost of operation is reported.

The Arvedi Endless Strip Production plant to be startedin Cremona, Italy, is presented. The design and plantconfiguration of this facility will allow fully-continuous castingand, for the first time in the world, endless rolling of highqualitystrip in a wide range of steel grades.