A comparative study between the mineral coals used by ArcelorMittal Tubarão has been carried out, aiming at determining complementing criteria to the current energy model for the mineral coals purchasing qualification used for injection in the blast furnace. Material characterization techniques were employed allowing the mapping of the characteristics of the coals which potentially affect the stability of the pig iron production process.


Solid and liquid iron oxides exhibit characteristics of semiconductors. The semiconductive behavior also features in some slags containing iron oxide. This paper aims at highlighting some of the experimental indications of the role of semiconductivity in electrical conduction, the chemical diffusion and in reaction kinetics at slag surfaces. It is not a thorough review of the subject matter but an attempt at shedding some light on the connection between these properties.

The development of new highly sophisticated steel grades with extreme demands on cleanness requires accurate refining. The paper gives an overview on the state-of-the-art in secondary metallurgy and describes the trends in secondary metallurgy research in Germany.

UST rejection ratio of heavy plates was relatively high since the 300 mm thickness slab caster has been operated at Pohang Works. An internal quality prediction system for slab was developed that can evaluate the center segregation level of slabs within 5 minutes after cutting. The rejection ratio of heavy plate thicker than 70 mm could be reduced effectively from 5% down to below 0.5% by applying this technology.

A new automated system installed in the ArcelorMittal Asturias steel plant in Avilés, based on novel image treatment, aims at performing an on-line inspection, with feed-back to the process, verifying the effectiveness of scarfing. It detects remaining defects as well as new ones introduced by this operation, thus allowing a quick and reliable assessment of final surface quality.

The relationship between water quality management and the total cost of operation of the steel mill are normally underestimated as areas of relevant cost reduction and productivity improvements. The work that was accomplished on cooling water systems associated with n°4 slab caster at CSN from 2004 to increase significantly steel plant productivity and reduce the total cost of operation is reported.

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