In order to increase their production of steel plates to 7.5 million tons/year, ArcelorMittal Tubarão faced the challenge to increase sinter plant productivity from 34.00 t/d/m2 to 42.00 t/d/m2. This was achieved in June 2006 through three main actuators: raw materials, stabilization and optimization of the current equipment and implementation of new technologies.

Steel making based on scrap melting is a substantial source of electric disturbances, such as voltage fluctuations, flicker, harmonics and unbalance between phases: unless mitigated, they all will spread over the feeding grid, violate the grid code, and disturb other users connected to the same grid. With SVC (Static Var Compensator) and/or STATCOM, grid disturbances can be efficiently and cost effectively mitigated, enabling the plant owner to meet the valid grid codes. At the same time, productivity can be increased and production economy can be improved.
The paper presents SVC and STATCOM for steel plant applications; goes into the latest technology, and highlights a couple of recent, state of the art installations and their benefits in steel manufacturing.

The mechanism of cleanness improvement with bubbles is reviewed. Bubbling through the down-leg snorkel of a RH has been modelled. This process was then experimented on a RH in POSCO, allowing a significant reduction of the inclusion content of slabs.

Work based on both water model experiments and numerical investigations is presented. Basic flow pattern in a continuous slab casting mould adopting a BSP type nozzle is studied by numerical simulation performed by the in-house code of Visual Cast II, hiring the k-ε model, with results validated by water model experiments. The structure of turbulence in the mould is further studied by LES. The preliminary results reveal a certain match on transient flow patterns with the water model experiments.

A broad range of steel industry liquid effluents have been collected from Corus site discharges for characterisation of their chemical composition, their toxicity to the aquatic environment and their oestrogenicity. This work was done as part of a European funded research project, in order to investigate the potential impacts of the Water Framework Directive on steel industry processes.

An integrated model developed by ArcelorMittal and NSC to predict the microstructural evolution of austenite in conventional and microalloyed HSLA steels during multi-pass hot rolling is described. The prediction of austenite grain size, recrystallized fraction, residual strain and precipitation state are given. Applications of this model during mono-deformation tests and during multi-pass rolling are presented.

The transformation model and the model-predictive coolingsection control system not only have decisive advantages when it comes to the production of multiphase steels; the quality of other materials such as highly carbonized steels, tool steels, transformer sheeting and many other materials is also improved.
Especially for older plants with many restrictions and limitations, the new cooling-section automation system allows for flexible manufacture of modern steel grades. Although the implementation of the micro structure target cooling system alone may result already in the required flexibility and quality, additionally by small mechanical modifications a plant may be brought to its peak-performance being ready for the challenges in future.