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 sourceof electric disturbances, such as voltage fluctuations, flicker,harmonics and unbalance between phases: unless mitigated,they all will spread over the feeding grid, violate the gridcode, and disturb other users connected to the same grid.With SVC (Static Var Compensator) and/or STATCOM, griddisturbances can be efficiently and cost effectively mitigated,enabling the plant owner to meet the valid grid codes. Atthe same time, productivity can be increased and productioneconomy can be improved.
The paper presents SVC and STATCOM for steel plantapplications; goes into the latest technology, and highlights acouple of recent, state of the art installations and their benefitsin steel manufacturing.

The mechanism of cleanness improvement with bubbles isreviewed. Bubbling through the down-leg snorkel of a RHhas been modelled. This process was then experimented ona RH in POSCO, allowing a significant reduction of theinclusion content of slabs.

Work based on both water model experiments and numericalinvestigations is presented. Basic flow pattern in a continuousslab casting mould adopting a BSP type nozzle is studied bynumerical simulation performed by the in-house code ofVisual Cast II, hiring the k-ε model, with results validatedby water model experiments. The structure of turbulence inthe mould is further studied by LES. The preliminary resultsreveal a certain match on transient flow patterns with thewater model experiments.

A broad range of steel industry liquid effluents have beencollected from Corus site discharges for characterisation of theirchemical composition, their toxicity to the aquatic environmentand their oestrogenicity. This work was done as part of aEuropean funded research project, in order to investigate thepotential impacts of the Water Framework Directive on steelindustry processes.

An integrated model developed by ArcelorMittal andNSC to predict the microstructural evolution of austenite inconventional and microalloyed HSLA steels during multi-passhot rolling is described. The prediction of austenite grain size,recrystallized fraction, residual strain and precipitation stateare given. Applications of this model during mono-deformationtests and during multi-pass rolling are presented.

The transformation model and the model-predictive coolingsectioncontrol system not only have decisive advantageswhen it comes to the production of multiphase steels; thequality of other materials such as highly carbonized steels,tool steels, transformer sheeting and many other materials isalso improved.
Especially for older plants with many restrictions andlimitations, the new cooling-section automation system allowsfor flexible manufacture of modern steel grades. Although theimplementation of the micro structure target cooling systemalone may result already in the required flexibility and quality,additionally by small mechanical modifications a plant maybe brought to its peak-performance being ready for thechallenges in future.