Anthracite coal as fuel for iron ore sintering is compared withcoke breeze. Anthracite is lower in porosity, higher in density, andslower in combustion rate. With higher proportion of anthracite infuel, permeability of sinter bed tends to decrease resulting in lowersinter productivity. Higher fuel rate with more replacement of cokebreeze by anthracite is ascribed to the lower density of heat sourceparticles and to the lower heat value and more volatile matters ofanthracite. A smaller particle size for anthracite is recommended.Some subsidiary heat sources such as magnetite ore and mill scalecould be helpful for more uniform sintering.

Ternium Siderar has recently installed a commercial sensor that measures the soundoriginated during blowing. A proper analysis of this signal may give valuable informationabout the slopping tendency of the heat. Data from more than 4000 heats were collected andthoroughly analyzed. The influences of the materials charged and of their compositions onthe slag slopping tendency were investigated. Based on these results, an application toevaluate the risk of slopping for given process conditions was developed.

Strip casting technology has many advantages, both technical and economical. In the Eurostrip project, this technology is applied to stainless steel at Krefeld (KTN) and to carbon steel at Terni (AST). The latest achievements of this technology are presented in this paper. Positive results are reported with respect to casting width, in-line hot rolling, in combination with in-line inductive heating. The technology is ready for industrial application.

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.

An expert system model for a fume extraction system has been developed and installed at an electric arc furnace steelplant. Expert rules advise plant engineers of plant abnormalities that could result in fugitive emissions to atmosphere and/or result in excessive energy consumption. Neural network algorithms are incorporated into the model to mimic instrumentation and to analyse general trends. Since the installation of a prototype, significant financial savings have been made.

The hot tearing of aluminium-copper alloys is a serious defect for the foundrymen. The grain refinement of these alloys allows to decrease their hot tearing susceptibility. The aim of this work is to better understand the hot tearing mechanism and the grain refinement action. So, hot tearing tests and tensile tests in the mushy state have been performed. Moreover, a hot tearing model, based on the nucleation and growth of a cavity in a liquid film and taking into account the mushy zone rheology, has been developed.

In the context of a rapidly growing energy demand and concerns about global climate change, renewable energies and in particular photovoltaic (PV) power are considered long-term solutions towards secured energy supply and for the reduction of greenhouse gas emissions. However, is solar PV a truly sustainable solution? Climate change will certainly not be the only environmental issue we will have to deal with. Regarding the issue of mineral resources, current research efforts aim at reducing raw material consumption in the manufacturing of PV panels. But, how do we assess the environmental efficiency of a panel, especially concerning the raw material consumption? Moreover, the PV industry consumes raw materials which are principally produced in non-EU countries such as Cadmium (Cd), Gallium (Ga) and Indium (In). How do we consider the issue of critical substance and accessibility? Required materials for PV modules may also be used in other applications (for example Gallium and Indium in electrical appliance production). Should competitiveness between applications be taken into account in a sustainability assessment? Are we going to valorize the PV module ability to use substitute substances? In addition to responsible resource management indicators, many other aspects have to be taken into account in order to achieve a complete sustainability assessment, especially recyclability, viability of PV industry, equilibrium along the value chain or social indicators such as social acceptability... Designing sustainability metrics is a new and complex research field. The whole value chain has to be evaluated and all dimensions (environmental, economic, and social) need to be explored. The paper will discuss the issues in defining sustainability metrics and propose some methodologies and a system of indicators to lassess the sustainability of a PV module.

The Direct Reduction process can be carried out usingsyngas from biomass. Mathematical models of theintegrated process gasification plus direct reductionhave been used to evaluate flow rate, temperature andcomposition of the gas in the various steps of the wholeprocess. Fluidised bed gasification and operation withtechnological oxygen at high pressures is the proposedsolution to produce syngas. Best candidates for suchapplication are biomass from forest and wood industryand agricultural residues. Both of such type of biomassare present and distributed in many European areasin such amount to make industrially possible their use,taking into account the logistic requirements. A costbetween 30-60 Euros/t DRI is roughly estimated.
The characteristics of the syngas implies the adoptionof purification steps, before the use of the syngas inthe shaft furnace, using technologies permitting hot gascleaning, to save energy efficiency of the process.

The maximum value at equilibrium of the relaxed enthalpy of some glasses is viewed as alinear function of the annealing temperature from the Kauzmann temperatureTK up to a vitreous transition temperature T*g which is not time dependent. The frozen enthalpy and entropy at T*gare determined from the specific heat difference between glass andundercooled melt which is constant between TKandT*g. The Gibbs free energy change at T*g is equal to zero. The vitreous transition is a thermodynamic transitionwithout latent heat. A model is used to describe this phenomenon. A volume energy saving εv equivalent to a complementary Laplace pressure has beenadded to the classical Gibbs free energy change for a crystal formation in a melt. Thereis a change of the Vogel–Fulcher–Tammann (VFT) temperature at T*g corresponding to a decrease of the free volume disappearancetemperature. Scaling laws linking the crystal homogeneous nucleation temperatures to T*g are used to predict the two VFT temperatures, the thermodynamic vitreoustransition induced by vitreous (super)-clusters and the frozen enthalpy and entropy at T*g only knowing T*g, the melting temperature Tmand the fusion heat ΔHm of any fragileglass-forming melt.

Critical parameters that affect both the ferrite grain size and the precipitation kinetics during hot rolling Nb-bearing steel were studied.Accelerated cooling was applied after the last pass of finishing rolling.In all cases the Nb(C,N) precipitation was strongly retarded, increasingthe precipitation hardening by the formation of fine precipitates.Moreover a non-negligible amount of Nb remained in solution. Nb(C,N)precipitation occurred during annealing cold rolled steel, causingsecondary hardening.

The work presents results of investigations and microstructural analyses for Mg-SiCp cast composites. The metallographic examination shows that the distribution of SiC particles is uniform. Quantitative image analysis of the microstructure shows the magnesium grain size to be smaller and more uniform than in the base metal. The studies at the level of the interfaces suggest that the bonding between the matrix and the reinforcement is of the adhesive type. The presence of the Mg2Si compound in the composites has also been revealed. Additionally, some compounds seem to be present at the SiC/matrix interface. The performed analyses have allowed to propose a model description of the process of the formation of the Mg-SiC composite structure. Mechanical testing has shown that composites have increased YoungÕs modulus and proof stress (R$_{{\rm p 0,2}}$) and decreased impact strength.

Strip rolling processes depend critically on friction and lubrication for process control as well as for strip quality. Pechiney and Usinor companies have therefore joined with CNRS (National Scientific Research Centre of France) to build an ambitious project gathering seven French public laboratories and their own research centres, Irsid and Centre de Recherches de Voreppe. The two major fields of lubrication were addressed: the formation of fluid lubricant films between rough deformable surfaces, and the formation of boundary films (tribochemistry). The final purpose was to derive a model of rolling processes including a predictive, local friction model. This issue and a future issue of Science et Génie des Matériaux present the efforts and the results of this Research Programme Contract "Materials forming: metal - tools - lubricant contact".

Development of metallic glasses is hindered by the difficulties in manufacturing bulk parts. We report on the preparation of glassy alloys using the spark plasma sintering of gas atomized powders. The Zr57Cu20Al10Ni8Ti5 alloy processed has a high glass forming ability. Densification is obtained at the glass transition temperature (390 °C) under high pressure (≈500 MPa). Systematic study of the effect of powder particles size and sintering time is performed through structural and thermal analyses. Local and partial devitrification of the amorphous alloy is detected, resulting from local temperature overshoots. From these analyses, an approach of the spark plasma sintering mechanism of metallic glasses is proposed.

Blast furnace models are fundamental tools that interpretmany of the phenomena occurring inside the reactor. Theycan be either diagnosis or predictive, but they requireavailable measurements to validate their outputs. One of theroles of the different R&D Labs of the ArcelorMittal Group is todevelop, validate, apply and continuously improve the modelsfor blast furnace operations and analysis. The users' feedbackis one important key to success.

ThyssenKrupp Steel AG has developed a numerical model tostudy the combustion of coal particles which are fed into theblast furnace through the tuyeres. The basic aim is to evaluatevarious coal lance / tuyere configurations and assess theiradvantages or drawbacks for successful operation. In theULCOS project, this model was used to check the feasibilityof some tuyere configurations for the Top Gas Recycling BlastFurnace process, which is especially challenging regardingtuyere design, combustion kinetics and raceway size.


The accidental melting of radioactive sources is impossible to prevent completely because some radioactive sources are extremely difficult to detect. When a radioactive source is melted, the people involved have concern for their safety, and there can also be very large costs to the steel plant. The aim of this study, sponsored by the European Commission, has been to give guidance to steel makers on the radiation safety aspects of an incident, and on what measures should be taken to minimize the impact on the steel plant.

Cet article est dédié à la description de la problématique de la corrosion sous contrainte assistée par l’irradiation (IASCC – Irradiation Assisted Stress Corrosion Cracking). Ce mode d’endommagement est observé dans les structures d’internes de réacteurs nucléaires à eau légère (REL) qui sont soumises à un milieu caloporteur chimiquement agressif et à l’irradiation. Après une présentation de la problématique industrielle liée à l’IASCC, notamment pour les réacteurs à eau pressurisée (REP) où les structures d’internes sont essentiellement en aciers austénitiques inoxydables (AISI 304 et 316), les facteurs contribuant potentiellement à l’endommagement par IASCC et leur effet individuel sur l’altération des propriétés du matériau sont passés en revue. La nature multiphysique du phénomène d’IASCC est ensuite présentée. Les stratégies et les outils mis en œuvre pour développer un modèle prédictif unifié sont ensuite présentés et discutés.

In order to limit the thermal gradient of plates during quenching and limit flatness issues, it is necessary to control the cooling. This control requires the knowledge of the cooling performances of the cooling device. This paper describes the equipments and procedure we developed for the on-line characterization of quenching. We illustrate the application of this methodology to the quench of Burns Harbor. After the austenitzing furnace, this quench is equipped with 3 cooling sections that have been characterized for several flow rates, for several speeds of plates and for the top and bottom sides of plates. Thanks to the collected data, heat fluxes have been calculated and correlations describing the cooling performances of the equipment have been built. These correlations have been implemented in a thermal model that gives the thermal state of a plate during cooling according to parameters like thickness of the plate, flow rates of the cooling sections, speed of the plate, and temperature after heating. Experimental and numerical results are discussed.

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 order to develop a new, efficient industrial process forproducing high quality iron and steel with significantly reducedcarbon dioxide emissions, we investigated the electrowinningof iron from an iron oxide ore in aqueous alkaline solutions.Hematite (Fe2O3) solid particles suspended in the concentratedaqueous sodium hydroxide (NaOH) solutions were transferredto the cathode (e.g., a rotating disk graphite electrode) andreduced to iron metal by applying a constant current; oxygenwas evolved on the anode (e.g., a nickel screen mesh). Currentefficiencies of above 90% with respect to iron depositionwere consistently obtained under the specific conditions in alaboratory cell, and the corresponding energy consumptionswere calculated to be around 3 kWh·kg-1 iron. The depositediron crystals were the oriented clusters of stacked six-fold twins ina tetrahedron-shape grew growing in a direction perpendicularto the cathode surface. Influences of rotation rates of the cathode,cathodic current densities, contents of the Fe2O3 particlesin electrolytes, and concentrations of NaOH solutions oncurrent efficiency and morphology of deposits were studied.