Today's steelmaking is constantly challenged by increasing quality demand and the term “Clean Steel” has gained more and more ground. In many steel plants, slag carry over from the ladle into the tundish is negatively influencing the quality of steel. When the casting starts, the steel flows undisturbed through the defined bore of the seating block and inner nozzle, the whole cross section of the bore filled with steel, but due to the vortex-effect a slag core appears in the centre of the steel stream towards the end of the casting. The solution is the Clean Steel Block, a combination of seating block and purge plugs in the corners. First trials in different steel plants indicated that the installation of the Clean Steel Block will constantly suppress the vortex-effect and increases the quality of the semi-finished product.

A review of recent developments in imaging with a transmission electron microscope is proposed here. A first part is devoted to applications in the “imaging” mode: interest of field emission, “Z-contrast”, quantitative high resolution electron microscopy and reconstruction techniques. A second part will deal with the “diffraction” mode: convergent beam diffraction and “electron cristallography”.

Hardening precipitation in an intergranular-corrosion desensitized alloy, AA6056-T78, is characterized in comparison with that in AA6013 and AA6082 alloys. To extract quantitative information, image-analysis is applied to dark-field images and selected-area diffraction patterns, along with standardless EDX spectroscopy. The central result is that both needle-shaped and lath-shaped precipitates have a similar chemical composition (except for Al content remaining undetermined in this study) to each other and, furthermore, to that of most of the grain boundary precipitates, normally in a more advanced state of precipitation kinetics than those in the grains.

Single crystals of the low stacking fault energy Cu-2%Al alloy, with initial orientation {112}<111>, have been deformed by compression in a channel die at 77 and 293 K. Microstructural and microtextural aspects of the formed brass-type shear bands were analyzed. Experimental techniques included TEM, SEM, optical microscopy together with SEM/EBSD and TEM/CBED microtexture measurements. The crystals first rotate by slip, then transform their orientation by deformation twinning. As shear banding starts, a strong increase of intensities near the Goss {110}<100> position is observed, and this process is connected with the rotation of twin lamellae within shear bands. At the TEM scale a second weaker component is noticed. Outside the bands, the twin-matrix lamellae rotate differently and the material reorients to {111}<112>.

As part of a complete theoretical description of the behaviour of the electric arc in the vacuum arc remelting process, a model has been developed for the column of plasma generated by a single cluster of cathode microspots. The model aims in particular to calculate the distribution of thermal energy transferred by the plasma to the surface of the anodic melt pool. The theoretical approach combines a kinetic model, taking into account the formation of the plasma in the cathodic region, and a hydrodynamic model, describing the expansion of the plasma in the vacuum between the electrodes.

The aim was to reduce sea water consumption at CST to optimize the electrical energy sale and to keep down the future needs in investments to provide sea water for the future power plant. Through the analysis of the consumption of the power plant condensers, it was possible to change the standard for the sea water pump operation. CST has decided to operate with two sea water pumps instead of three, and this change resulted in a reduction of the demand for electric energy at CST of 1.6% or 2.6 MW or 22,776,000 kWh/year.

For the promotion of zero emission society, the recycling of dust and sludge produced in the steel making process, leading to the recovery of valuable metals like Iron, Zinc, Nickel and Chromium, has highly attracted public attention. The Plant and Machinery Division of Nippon Steel Corporation has introduced the basic technologies of the rotary hearth furnace, DryIronTM Process, from Maumee Research & Engineering Inc. in the United States, and developed the process in order to recycle such dust and sludge effectively. In addition, the DryIronTM Process can also produce direct reduced iron from virgin iron ore and non-coking coal. In this paper, the features of the DryIronTM Process and the machine outline in Hikari Works of Nippon Steel Corporation are described.

In the present paper, a synthesis of the relations between diffraction stress analysis and multiscale modelling is presented. It is found that, although models give good qualitative and quantitative results in the elastic field, the extension to internal stresses of elastic-plastic origin remains semi-quantitative and many studies are still required to obtain a consistent formulation between diffraction and modelling.

For vacuum tank degassing, dynamic process models for dehydrogenation, denitrogenation, desulphurization, decarburization, the course of steel temperature and the removal of non-metallic inclusions were developed. They were validated by comparison of simulation results with measured process data from different vacuum tank degassing plants. The models are applied for on-line process observation, providing the operator with information on the current heat status, which is normally not available during the degassing process under vacuum.

Shredded old tires can replace coke in the electric arc furnace, if some simple rules are followed to charge and use them. Experimental runs were carried out in two French steelshops for longer and longer periods of time and the substitution rate of carbon by tires was determined. Environmental measurements were also made in order to check emissions in the smokestack and inside the shop.

This tribute presents different ways in which Jean Morlet stimulated the cooperation between basic and industrial research : identification and optimum use of the fundamental competences able to contribute to the enhancement of the industrial skills, actor and coordinator in the area of public research, supporter of an interdisciplinary approach, active member of the scientific community.

Companhia Siderúrgica de Tubarão (CST) has continually been carrying out process improvements in order to increase and maintain the slab production to 5 Mt/year. The technology that makes it possible to start the continuous casting using a tundish at cold temperature is one of the developments that will help CST to meet that goal. This paper describes the implementation of the cold tundish at CST, using the approach already adopted at other plants of the Arcelor Group. Through the implementation of the cold tundish process it was possible to reduce not only the time for setting-up the continuous casting machine, but also the gas consumption and the noise at the casting platform, thus improving the operators environment.

The coke making industry has seen substantial technological development over the last decade. Conventional coke ovens (slot type ovens) with raw gas recovery have reached dimensions of more than 8 m height and 90 m3 useful oven volume, boosting the capacity of a single battery to 1.3 Mt/y and the production of a single coke plant with one operating team to 2.6 Mt/y. At the same time, the emissions from batteries and gas treatment facilities have been reduced to the lowest amounts ever. A further increase in energy efficiency and environmental protection for conventional coke batteries is expected from the combustion of the hot raw gas with subsequent generation of electricity. The concept of a coke plant with direct combustion of the raw gas would omit the entire gas treatment plant and produce only coke and power. Aside from these achievements with conventional coke oven batteries, the non-recovery technology has also found acceptance. Coke plants of this type are in operation in the USA, Australia and India. One plant in the USA is a heat-recovery coke plant that produces power from the waste gas. Further improvements in plant efficiency and coke quality are achieved with stamping of the coal charge, which is now developed for non-recovery ovens, too.

Mechanisms of deformation in an age-hardenable Ni-Mo-Cr alloy containing large precipitates of the coherent ordered phase were investigated. The dominant deformation mechanism in the examined alloy depended on the applied amount of strain: for low strains micro-twinning within the ordered precipitates and dislocation slip in the matrix prevailed; at higher strains the f.c.c. twinning became the major deformation mechanism. Micro-twinning within the ordered phase was size related - micro-twins occur in large precipitates at relatively small strains. Twinning within the ordered precipitates may occur in all possible twin systems. Ten out of twelve possible twinning systems lead to the formation of true twins, and the long range order is preserved in the twinned regions. Formation of shear bands at high strains destroys the long range order.

A new industrial process allowing to reach very high cooling rates in the cooling section after soaking of a continuous annealing line for steel sheets is presented. This process constitutes the successful conclusion of a long term research programme, jointly carried out at CRM and Arcelor Cockerill-Sambre for three years, including laboratory experiments, pilot scale trials and several industrial campaigns. It is running on from developments performed in the framework of the HOWAQ (Hot Water Quench) process. The process successively combines a moderate cooling step (600 °C/s for 0.8 mm thick strips), in boiling water, and a faster cooling step (above 700 °C/s), by impinging turbulent cold water in a box. Its main features are simplicity, resulting from advanced developments, soundness, flexibility and cooling homogeneity. As treated steel products are characterized by improved mechanical properties, outstanding surface quality (corrosion resistance) and exceptional flatness. The process is implemented industrially since the beginning of 2002.

The wish to increase the production capacity of the Dunkirk plant has led the steel shop to modify the refractories in order to respond better to these new conditions. The first target is to produce 6.7 Mt of hot metal per year on the three blast furnaces of Dunkirk, and the second, after the relining of blast furnace No. 3 planned in 2004, to produce 6.9 Mt of hot metal, in order to cast more slabs (6.7 Mt of steel). One of the main challenges is to increase the capacity of the steel ladles from 240 to 270 t and, at the same time, to improve reliability. For all these reasons, work for the design of new ladles is really complex and different trials are on the way on wall structure, monolithic bottoms, lip ring, and repairs.

The determination of residual stresses and the analysis of phases in zirconia layers obtained after oxidation of Zy-4 and Zr-1%Nb-O sheets have been performed using X-ray diffraction with synchrotron radiation at 20 and 400°C. These experimental analyses have been compared with calculations using a micromechanical approach (thermoelastic behaviour) and also with a macroscopic approximation of the thermal stress due to cooling. The main result is the small influence of cooling on the residual stresses developing in the zirconia layer, especially for Zr-1%Nb-O.

The multiple versions of electromagnetic stirring in continuous casting are described. For long products, linear or rotational stirring appears confusing, but is clarified based on liquid steel flow pattern and metallurgical results. Rotational mould stirring is the predominant application. For slabs, butterfly type single and double strand stirring and rotational mould stirring coexist with different metallurgical purposes. Also, the evolution to higher casting speeds has required a new type of mould stirring that combines accelerating and braking functions. The trend goes to multi-mode systems.

The present status of thin slab hot rolling (TSHR) technology is reviewed, with the emphasis on installations in operation or under construction in Asia. Core technologies required to manufacture steel products are EAF or BOF steelmaking, specific continuous casters, hot rolling practices preventing the formation of edge cracks or surface defects. TSHR can produce as well economical commercial products as high grade products. The main advantages of this route are presented and ways to overcome some of its limitations are suggested.