This paper presents a probabilistic method for fatigue life estimation within thefrequency domain for structural elements subjected to multiaxial random loadings.Multivariate Monte Carlo Simulation is used to account for the correlation between thestress components and their different probability of occurrence and, moreover, enablesstochastics during damage analysis to be allowed for and, at the same time, uses anysuitable, material dependent multiaxial fatigue criterion known from the time domain.Comparison of the evaluated fatigue damage with experimental results from vibration testson a demonstrator, chosen from common application fields in the automobile industry, showsgood correlation.

To optimize the process and improve the degree of reduction, a two-stage experiment wasdesigned. It was carried out in a micro-fluidized bed. It is operated as a differentialreactor to ensure every particle in the micro-fluidized bed is at equal temperature,concentration and residence time. The experiment used iron ore powder from Yangdi. Thereducing gas and temperature in the pre-reduction stage were, respectively, pure CO and625 °C. In the final reduction stage, the temperature and reducing gas were, respectively,800 °C and pure CO. The residence time was between 10 min and 60 min. In addition to theexperiment, a microscopic technique was also carried out. The test shows a significantinfluence of the temperature and residence time of the two-step experiment on the finalreduction degree.

In March 2000, a new compact steelmaking plant of Suez Steel (Adabia, Egypt), erected by VOEST-ALPINE Industrieanlagenbau (VAI), has successfully been started up. With a Finger Shaft type electric arc furnace (FUCHS system), a ladle furnace and a 5-strand caster, this highly modern plant has a capacity of 600,000 t/year of structural steel billets. Since the start up, new production records are continuously established.

A new SSMR process to produce ultra-fine-grained hot strip is introduced,featuring: closely spaced rolling stands, continuous highspeed rolling with moderately large reductions rolling, rapid interpasscooling and rapid finish rolling cooling. An ultra-fine-grained CMnsteel strip (1μm) is obtained with a 700 MPa yield stress. Aproper choice of the work roll diameter and a careful control of thefriction coefficient should make it possible to keep the rolling forceat a level compatible with the design capacity of a conventional rollingmill.

Cementite decomposition leading to the formation of the whiteetching layer (WEL) on the surface of rail tracks was investigated byelectron energy loss spectroscopy (EELS) in the TEM and by threedimensionalatom probe (3D-AP). It is shown that the carbonconcentration inside cementite laths undergoing severe plasticdeformation in the transition zone between the pearlitic substrateand the WEL remains stoechiometric. However there exists a boundarylayer at the ferrite/cementite interface where the carbon compositiondecreases, indicating that decomposition is an interfacialphenomenon. Carbon atoms diffuse into the ferrite and segregatealong structural defects leading to a heterogeneous supersaturatedcomposition in the white etching layer.

The Young's modulus (E) of steels varies with their chemical composition, the manufacturing conditions of the products, the orientation ot the test samples within a given sheet. The knowledge of its exact value is important for the optimum choice of the steel grade best suited for the production of structural parts. Several methods are available for the determination of the modulus of elasticity. At LEDEPP, a tension test method is used, but it is considered that a method based on the measurement of the resonance frequency should be advantageous. As it is a non-destructive method, various research directions can be explored, like the variation of E with orientation, temperature or prestrain. Both methods are described and their results compared.

Coke production capacity within AM FCWE is not self sufficient forthe total HM production. PCI was started up in 2004 at Bremen BF2and Eisenhüttenstadt BF5, with a ramp up to 180 kg/thm in one year.A working group defined the BF operating conditions leading to stableand efficient operation at high PCI. At Florange BF3 PCI trials at220 kg/thm were successful. At Dunkerque BF4 and Gent BFA andB, the PCI rate exceeds regularly 210 kg/thm.

Using an IF-steel, the application of ferritic rolling in the thin slab direct rolling technology has been studied with the objective of producing thin hot rolled strip with good deep-drawing properties. The effect of the main processing parameters has been simulated in the case of the production of two types of finished products: "soft" hot strip (completely recrystallized during coiling), "hard" strip (obtained with low finishing and coiling temperatures and subsequently annealed).

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 tools of the hot strip mill are reviewed in details: furnace, roughingmill, descalings, finishing mill and coolings involved in themodification of the transverse thermal profile. Industrial databases,numerical simulations and experiences are used to identify the mainparameters and their influence. From this analysis actions are definedthat could be taken to improve or to preserve the thermal profile.

Three hundred years after the first production of coke, the history of this importantbreakthrough, an energy transition that, together with the invention of the steam engine,opened way to the industrial revolution, is still thought provoking on subjects such asthe rate of change and the factors that are favoring or slowing down the rate of change,the role of infrastructure and technology in the development of industry, the role ofprotectionism or free-trade on technological changes and last, but not the least, thedevelopment of science and technology as tools for the improvement of the processes andproducts. From the first information of G. Jars and his metallurgical trips and the smallscale tests of the first pioneers of the Enlightment, to the development of large sizeplants incorporating new technologies, this history is that of the important social switchfrom a small scale peasant seasonal activity with many workshops, to the large scaleintegrated industry concentrated in a few places and connected with the suppliers and themarket by the new transportation infrastructure (canals, railways) developed incontinental Europe throughout the XIXth century. Scientists (such as Ebelmen, Lecocq,Boudouard, Berthellot) and technologists (such as the innovation brought by Belgianfurnaces) have played an important role in this mutation.

In 2003, the blast furnaces in Sollac Lorraine faced the challenge ofensuring self sufficiency in coke while maintaining a constant productionlevel. This challenge has been taken up successfully byreducing the coke ratio and by increasing PCI. This was achieved bychanging the tuyeres conditions, by optimizing burden quality andburden charging and improving the wall heat control.

The trapping of carbon by titanium in ferritic stainless steels with low interstitial contents depends on the presence of other non metallic elements such as phosphorus. The decrease of phosphorus content in the steels promotes the segregation of carbon at the grain boundaries and prevents the formation of the titanium carbonitrides. In fact, the formation of these precipitates depends on the quantity of remaining carbon in the matrix after the segregation of this element at the grain boundaries. Thus, this quantity could be sufficient to allow the formation of Ti(C, N) compounds by reduction of their solubility as the tempering temperature is decreased.

This paper addresses issues of material flows in a selection of modern steel plants,especially the generation of wastes, from a social sciences perspective. I analyse keyfactors structuring waste management decisions through the case of “problem” wastesarising at a steel company’s plants. I discuss how some materials come to be construed asmore problematical than others from a material and technological point of view, but alsoby taking into account organisational and legislative issues, in order to show that theconstruction of the “waste” category needs to be envisioned as resulting from a matrix ofsocio-material causes.

CRM developed a probe determining the raw material trajectories in bell-less top charging, by measuring the force generated by the material stream on a beam, in function of its position in the furnace. A prototype probe was tested on an industrial blast furnace during its first charging after a relining. These trials allowed the determination of both coke and sinter trajectories for the various chute angles. These results were validated by measurements carried out simultaneously by Irsid with painted bars.

This article synthesizes a number of studies involving both quantitative characterization of precipitate microstructures (size and volume fraction) and modelling of precipitation kinetics. The main experimental methods used are Small Angle X-ray and Neutron Scattering and Transmission Electron Microscopy. The modelling is based on semi-analytical models (coupled differential equations) and on numerical models (based on the discretization of the precipitate size distribution). A variety of systems are studied, both aluminium alloys and steels. After considering isothermal precipitation, the issues of dynamic and non-isothermal precipitation are discussed. Finally, precipitation phenomena occurring during welding are characterized.

Le but de ce travail est une contribution à l’étude de l’efficacité d’utilisation dutraitement de phosphatation au zinc pour la lutte contre la corrosion des armatures dansle béton. Pour réaliser cette conversion chimique superficielle, des échantillons en acierrond à béton ont subi une phosphatation cristalline dans un bain de phosphate de zincmodifié par des ions Ni2+. Par suite, nous avons évalué leur comportement à lacorrosion dans une solution simulée du béton au moyen de différentes techniquesélectrochimiques. Les résultats obtenus montrent que le traitement de phosphatation permetd’améliorer d’une manière significative la résistance à la corrosion de l’acier. En effet,les échantillons phosphatés, par rapport à ceux non phosphatés, présentent des valeurs depotentiel de corrosion et de piqûration plus nobles ainsi que des densités de courant decorrosion plus faibles. Les mesures d’impédances confirment cette tendance, les spectresobtenus montrent une nette augmentation de la résistance de transfert de chargesconjointement à une diminution de la capacité de la double couche électrochimique deséchantillons traités. Cette action protectrice est due au fait que la couche de phosphateobtenue joue le rôle de barrière physique face à la diffusion des ions chlorures d’unepart, sa dissolution en surface dans la solution simulée fortement alcaline libère lesions PO43- rentrant dans la réaction de formation d’un film depassivation jouant le rôle de barrière chimique face à l’amorçage de la corrosion parpiqûres, d’autre part.

“Consistent BOS Performance” was an ECSC funded project that began with the premise that internal converter shape influences process performance. Plant data were analyzed to quantify the effect of shape on performance and the process of slag splashing was studied in detail, as a means of shape control. It was found that the greatest influence on BOS performance is the availability of bottom agitation and this is affected by slag splashing practices.

Raw materials like metals and minerals contribute by 40% tothe production costs of the industry, whereas the costs forenergy are about 1.6%. Although these figures are for thetotal industrial production, the figures show that it can beexpected that there is a great potential for cost savings in thesteel production, too.

Dans le cadre de l’étude de la fatigue thermique de tuyauteries du parc de centralesnucléaires, des essais de fatigue multiaxiale à grand nombre de cycles sont effectués pourtenter de quantifier l’effet de la multiaxialité et de contrainte moyenne sur la durée devie du matériau et alimenter un modèle d’endommagement à deux échelles. Des outils demesures de champs cinématiques ainsi que d’observations micrographiques sont mis en placeafin de tirer le maximum d’information de chaque essai : comportement cyclique,déformation plastique progressive, scénario d’apparition des fissures. Des résultatsd’essais proportionnels et non-proportionnels sont présentés.