The multiplication of magnetic domain walls under the effect of induced currents developed during high frequency magnetization loops is experimentally investigated in ultra-soft nanocristalline alloys in order to determine the effective anisotropy and to check the predictions of the Random Anisotropy Model used to explain their extreme softness. For the first time, direct observation of multiplication is achieved and resulting effective anisotropy determinations underline the importance of induced anisotropy upon effective anisotropy.

The different ULSAB programmes offer steel solutions to the challenges facing automakers around the world today: increase fuel efficiency, improve vehicle performance and maintening affordability. In the ULSAB-AVC programme, the complete body structure consists of high strength steel with over 80% being advanced high strength steel grades. Application of advanced technology such as tailored blanks, tailored tubes, sheet and tube hydroforming, and extensive laser welding was also coupled with innovative design. The design and manufacturing features of ULSAB-AVC body structure are presented along CAE analysis and economic analysis results.

Recent developments in Scanning Electron Microscopy (SEM) are reviewed paying particular attention to the modern tendency to determine quantitative data in the form of microstructure maps : of chemical composition (EDS and WDS), of crystal orientation (EBSD) and of the deformation (microextensometry). The maps are then used to provide complete, quantitative microstructural analyses in terms of the size, orientation and composition distributions. In this context the new SEM-FEGs have an important role to play.

A new filler material, a stabilized ferritic welding wire, has been developed for the joining of the stabilized ferritic stainless steel sheets increasingly used in automotive exhaust systems. The joints obtained in the GMAW and GTAW processes behave at least as well in service as those obtained with austenitic filler wires. The new welding grade can also be applied to produce heterogeneous assemblies.

As a part of the Arcelor project concerning the prediction of the capability (“ Évaluation Prévisionnelle des Capabilités ” project), models are developed to predict the mechanical properties of austenitic stainless steel coils processed on the Ugine&ALZ integrated cold rolling line LC2i. Two approaches are used: statistical models resulting from an analysis of industrial databases, and physical based modelling accounting for the recrystallization mechanism during the final annealing to estimate the mechanical behaviour of the final product, including twinning and martensite induced transformation mechanisms. The work leads to the prediction of the yield stress and the tensile strength along the cold-rolled and annealed coil; the calculated mechanical values are in good agreement with the measurement on samples taken from coils of AISI 304 grade (UGINOX 18-9 E).

High strength steel is an interesting alternative for making steel structures more competitive. Its production and use in Europe is small compared to markets as Japan and USA. It would be of mutual benefit for producers and users if the use increased. The paper gives examples of successful use and a state of art concerning design of such structures. Possibilities for further development and obstacles to be overcome are also discussed.

The concept of forced alloys is explained and application examples are described. Systematic experiments with natural test pieces and by computer simulations show that, under the working conditions studied (irradiation, crushing, cyclic loading), the alloy may reach a stationnary configuration. Among the parameters controlling this process, the working intensity is of particular importance. The introduced concepts are applied to the study of the wear behaviour of fast train wheels (TGV). Wear rates and out-of-roundness are found to be proportional to this intensity.

A major evolution is in sight in the area of packaging steel. After a period of twenty years of continuous improvement of organic coatings for packagings, mainly those applied by varnishing, a totally new process for the coating of steel is under development : extrusion coating. This paper explains the stakes, the fabrication method and the evolutions of these new steel packagings, which will soon be present in our daily life.

The formation of recrystallization microstructure and texture in ferritic steel sheets used in the automotive industry is presented and involved mechanisms are discussed in connection with the substructure formed during the deformation preceding the annealing. Nucleation principally happens in the gamma-fibre grains, which develop smaller deformation cells and higher local misorientations than the alpha-fibre grains. The development of the nuclei is then analyzed by analogy with the abnormal coarsening which sometimes occurs after recrystallization. Finally, some relations between recrystallization textures / microstructures and mechanical properties are shown, like the effect of the rolling level on the anisotropy or the decrease of mechanical properties when under-recrystallisation happens.

From the viewpoint of a plate manufacturer, the status of steel plate quality for line pipe application is discussed. Technologies of the steel shop and the plate mill to create high class material are presented, as well as alloying and accelerated/intermediate cooling concepts. The levels of consistency that can be reached are illustrated on recent contracts. This includes sour gas resistant line pipe steels, applications for low temperatures and the extension of these features towards high strength grades.

Weathering steels are high strength low alloy steels that under normal atmospheric conditions give an enhanced resistance to rusting compared with that of conventional structural steels. The market for weathering steel bridges in the UK is growing exponentially. This paper describes the UK market for weathering steel bridges, highlights the benefits of the material, describes its limitations, and comments on the appearance of such bridges.

The ends of food cans are submitted to higher and higher loads due to the persistent thickness reduction required by the canmakers. A finite element model supported by experimental tests shows that the physical performances of lightened food can ends are perceptibly improved by using an adapted design and the new steel grade, having increased mechanical properties and ductility, developed by Arcelor Packaging International.

This article presents and discusses some modern techniques for high resolution orientation measurements in electron microscopy, including electron backscatter diffraction (EBSD) in the scanning electron microscope and spot and Kikuchi diffraction as well as dark field conical scanning in the transmission electron microscope. The techniques are compared with respect to their applicability to studies of nucleation processes during recrystallization of highly deformed metals. These investigations make high demands on orientation measurements, as high spatial and angular resolution and insensitivity to lattice defects are required.

The orientation distribution of high order twins is computed from the texture determined from neutron and EBSD measurements on a 70 % cold rolled Fe-36%Ni sample. As experimentally observed, during annealing, the simulated twinned texture tends to become isotropic. Moreover, as experimentally observed and numerically verified, it appears that three twin generations develop after the complete recrystallization. Finally, if it is obvious that both the nucleation (and growth) of all possible orientations of the cold rolling texture and the multiple twinning can contribute to explain the isotropic part formation of the recrystallization texture, and it seems that this second mechanism plays an important role.

Ultra-high strength steels with a tensile strength of 1,000 MPa to 1,200 MPa have been used for bumper and door beam since 15 years in Japan. Recently, it has been tried to apply these steels to reinforcements such as B-pillars inner and so on. The application of these types of steel tends to spread. Their formability, weldability and fatigue properties are described. Formability of ultra-high strength steel is different from that of mild steel, and it is governed by local elongation or stretch flangeability that can be evaluated by bendability. Local elongation or stretch flangeability has a negative correlation with total elongation. When strength exceeds 1,000 MPa, delayed fracture tends to occur. However, when measures to avoid delayed fracture are taken, there are no application examples of ultra-high strength steel sheet with 1,500 MPa tensile strength restricted by the danger of delayed fracture.

Since its introduction in the early eighties, Environmental Scanning Electron Microscopy (ESEM) proved a particularly useful tool in the characterisation of delicate samples mainly in the field of life sciences. Now, the potential of this equipment (no or little sample preparation, possible dynamic observation and reactivity studies...) is more and more employed in traditional materials domains. Some typical applications of ESEM concerning metallic compounds are presented.

First, it is demonstrated that the shape change accompanying bainite formation is accommodated by plastic deformation in austenite. Secondly, taking into account the corresponding plastic work, which increases due to carbon enrichment and transformation shear strain, as an entropy production mechanism, a new criterion, depending especially on initial chemical composition and grain size of austenite, is proposed for the stop of isothermal bainite before the expected equilibrium fraction expected from the phase diagram.

The corrosion resistance of two aluminium alloys, 6063 and 3003, has been compared using a 0.5 M sodium chloride solution. The results obtained with electrochemical and metallographic techniques show that alloy 6063 is more resistant than alloy 3003 at 25°C. The corrosion rate tends to increase as the pH deviates from neutrality. When the chloride concentration is decreased, the resistance to pitting corrosion is improved for both alloys. The influence of the temperature of the medium on the behaviour of the two alloys has also been studied. In the case of alloy 3003, the corrosion rate (Icor) increases with temperature up to 55°C, but drops back to its room temperature value at 65°C. In the case of alloy 6063, Icor decreases as temperature is raised up to 65°C. At all testing temperatures, the 6063 alloy has a better corrosion resistance than the 3003 alloy.

VAI Clecim and their customer partners have developed a new strip welder, adapted to the flash-butt-welding of even the newer types of steel (dual phase, TRIP) with their specific requirements. This welding machine is already in use at several steel rolling plants and gives best results.

Textures and local orientations have been determined in copper alloys after cold rolling and annealing. The measurements show that for a strain below a given threshold a mixed “deformation-recrystallization” texture is obtained after a static primary recrystallization : the {100}<001> cube orientation becomes stronger as annealing procedes, but is not dominating in the final microstructure. Global texture determinations by X-ray diffraction coupled with local orientation measurements by EBSD (Electron Back-Scattered Diffraction) show that in materials cold rolled by 70 and 80%, the orientation changes at the very beginning of the recrystallization process (i.e. at nucleation) are crucial for the formation of the recrystallization texture.