The inclusion populations and the relevant inspection methods are described with a particular emphasis on the SEM-FEG/EDS image analysis system. Then, the efficiency and the limits of the inspection methods are assessed by a new simulation approach.

Two complementary techniques are mainly used for the detection and characterisation of the inclusions populations present in the steel bars in a large range of sizes: from 1 μm to 1 mm: the automatic scanning electron microscope associated with image analysis and the 80 MHz ultrasonic inspection. The emphasis has been put on the composition of the inclusions whose size is above the critical size (10 - 20 μm) for long life fatigue. The mechanism of formation of these harmful inclusions is determined through the process with the help of thermodynamics models. This approach makes it possible to improve the process: avoiding slag entrapment upon casting of bearing steels, adjusting closely the Ca addition to calcium treated steels.


A calcium treatment is performed to improve the machinability of Al killed medium carbon steel grades. Modelling oxides with the software CEQCSI makes it possible to adapt the calcium level according to the contents in Al, S and O. The stability domain of the targeted oxides is quite narrow and highly dependent on both temperature and composition; thus the industrial practice turns out to be difficult. This is confirmed by the analyses of inclusions in some Ca-treated heats of ArcelorMittal Gandrange. However, their machinability properties were found to be 20 to 30% higher than those of the standard grade.

In December 2003, Rasselstein GmbH Germany placed an order with the consortium VAI (Consortium leader) and Drever (Furnace) for the erection of the new continuous annealing line n° 5. The construction of this annealing line takes place in a new building simultaneously with the construction of the tinning line n° 12. This modern line is unique in that for the first time it is planned to homogeneously anneal strips in widths from 800 to 1,400 mm. The future capacity amounts to 360,000 t. After annealing and finishing rolling the material is coated in a tinning line after which it finds use as an intermediate product for the beverage and packing industries.

The mechanical properties of a 10.5% chromium stainless steel strip have been determined as a function of the cold rolling reduction ratio. The best formability properties after annealing are associated to the higher cold deformation. This is a consequence of the texture development and through thickness homogeneity. The recristallized grains mis-orientation has been studied with the CSL approach and the coincidence index.

Ultra and Very High Strength Steels (UHSS, VHSS) solutions are proposed by ArcelorMittal to meet front, side, rear and rollover crash requirements. UHSS and VHSS steel monolithic solutions have strongly progressed crash safety and lightening. Another step towards higher performance is afforded by UHSS and VHSS Tailored Welded Blank (TWB) configurations. Three parts are analysed that participate actively in vehicle crashworthiness: sidemember, B-pillar reinforcement and front-end bumper. A comparison between monolithic solutions and TWB solutions is presented, in order to determinate the extra gains (i.e. mass saving, energy absorption) that a TWB solution can offer.