This paper describes a method for producing model composites by the powder metallurgy route in order to control the spatial distribution of the reinforcement in a metallic matrix. The materials are fabricated by successive steps including mixing and extrusion. They are then characterized in 3D by X-ray tomography.

The topography of grain boundary thermal grooves in the Ni-rich NiAl is studied by the atomic force microscopy. It is demonstrated how the processes of grain boundary sliding and surface faceting modify the shape of the grooves. The quantitative theory of grain boundary grooving that takes into account the above complications is developed. The great potential of grooving studies for the analysis of microstructure evolution is emphasized.

CPM developed a mechanical sensor to measure coke oven wall deflections. This sensor was used in Dunkirk coke plant under normal operating conditions and showed reversible deflections between 1 and 1.5 mm when plastic layers meet at the oven centre. Special blends, with a high content of low volatile coals, were charged in several ovens of the Drocourt coke plant. In those conditions, CPM noticed the same phenomena as in Dunkirk plant but also reversible wall deflections just after charging.

The application of finite element techniques to modelling the longproducts rolling process, the use of a customized interface to enablethe rapid set-up of sequential simulations, and the benefits thathave been obtained are described. The paper also discusses theenhancements to incorporate a design of experiments/design optimisationmodule and to enable material tracking.

Statistical methods have been used to analyze the thickness variations in coils of packaging steel. A sampling procedure has been defined in order to characterize the thickness variations in length and width directions for a given coil and from coil to coil. The analysis has allowed to evaluate the respective contribution of the various sources of scatter in relation with the production sequence and to define a strategy for the improvement of the results in this area.

TEM in situ straining experiments are of high interest in evidencing the dislocation mechanisms responsible for the macroscopic behaviour of materials. The application of this technique to biphased materials is illustrated here through various examples in which deformation is controlled either by dislocation propagation (e.g. precipitate overcoming) or by dislocation nucleation (e.g. interfacial sources).

Deux grandes classes de procédés ont été employées par les forgerons d’aciers dès lepremier millénaire av. J.-C. A partir de deux exemples typiques nous montrons commentl’interprétation des examens métallographiques avec des outils modernes tels que MEB etMEBFEG permet de reconstituer ces techniques. Un échantillon de l’époque mérovingienneillustre la fabrication de lames figurées par multiples opérations desoudage puis forgeage. Un échantillon de wootz prélevé dans une lame du XVIIIesiècle illustre le forgeage du fameux acier fondu de Damas.

With extremely high cooling rates, a combined laminar jet andspray nozzle design cooling facility is the most advanced tool forthe evolution of mechanical properties of high-strength steels. Themain metallurgical aspects of Accelerated Cooling (ACC) andDirect Quenching (DQ) are presented. Typical plate applicationsare brought up. Design, engineering and operational aspects ofmodern cooling facilities are explained. Of particular importancefor a homogenous cooling process is a powerful process controlfeaturing advanced process models.

The performance of lubrication systems for cold double reductionrolling has been investigated. Pilot mill trials have been achievedwith direct and recirculated emulsion application as well as with pureoil to analyse the effect of lubrication by emulsion on role bite frictionand the associated speed effect. It is then attempted to define anoptimized lubrication system that combines the advantages affordedby the direct and recirculated application systems.

Existing rolling mills entering the markets for high quality steel may be limited by their descaling systems installed in terms of pressure and flow rate. In addition to the potential for optimizations of existing systems, the potential for optimization of the nozzle design itself has now been fully utilized in order to maximize the impact at a given water flow and pressure. New design methods and production technologies have been applied.

The selective oxidation of three CMnSi steels with differentC levels was studied by XPS. The formation of a graduallycovering SiO2 film is observed until a transition temperatureabove which the oxide film disappears, resulting in a renewedappearance of metallic iron at the surface. This change inoxidation behavior is thought to be due to the SiO2 reductionby solute C which is thermodynamically favorable at hightemperature. At the same time the precipitation of a BN filmon the metallic surface was observed which prevented anyfurther oxidation.

Today, the numerical simulation of fluid dynamic phenomena(CFD) in steelmaking applications is state of the art. Thelatest simulation results for the BOF and AOD as well asthe thin strip casting process are described. The basicinfluence of the process parameters, e.g. blowing andstirring rate, vessel dimension, location of top lance, numberand arrangement of porous plugs, on the converter meltflow and mixing time is simulated. In the case of thin stripcasting, the free melt flow on the moving belt is influencedby an induced electromagnetic field. The respective MHD(magneto-hydrodynamic) is presented.

This article tells in the form of a tribute to chairman René Damien, the founder of Usinor, the story of the French wide strip mills. The situation of the French steel industry in the 1950s is first recalled. The important decisions made to modernize this industry are then presented and the major milestones of the construction and operation of the hot strip mills of Denain, Serémange, Dunkirk and Fos are indicated.