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

Two complementary techniques are mainly used for the detectionand characterisation of the inclusions populations present in thesteel bars in a large range of sizes: from 1 μm to 1 mm: the automaticscanning electron microscope associated with image analysisand the 80 MHz ultrasonic inspection. The emphasis has been puton the composition of the inclusions whose size is above the criticalsize (10 - 20 μm) for long life fatigue. The mechanism of formation ofthese harmful inclusions is determined through the process with thehelp of thermodynamics models. This approach makes it possible toimprove the process: avoiding slag entrapment upon casting of bearingsteels, adjusting closely the Ca addition to calcium treatedsteels.


A calcium treatment is performed to improve the machinability of Alkilled medium carbon steel grades. Modelling oxides with the softwareCEQCSI makes it possible to adapt the calcium level accordingto the contents in Al, S and O. The stability domain of the targetedoxides is quite narrow and highly dependent on both temperatureand composition; thus the industrial practice turns out to be difficult.This is confirmed by the analyses of inclusions in some Ca-treatedheats of ArcelorMittal Gandrange. However, their machinability propertieswere found to be 20 to 30% higher than those of the standardgrade.

In December 2003, Rasselstein GmbH Germany placed an orderwith the consortium VAI (Consortium leader) and Drever (Furnace)for the erection of the new continuous annealing line n° 5. The constructionof this annealing line takes place in a new building simultaneouslywith the construction of the tinning line n° 12. This modernline is unique in that for the first time it is planned to homogeneouslyanneal strips in widths from 800 to 1,400 mm. The future capacityamounts to 360,000 t. After annealing and finishing rolling thematerial is coated in a tinning line after which it finds use as an intermediateproduct for the beverage and packing industries.

The mechanical properties of a 10.5% chromium stainless steel striphave been determined as a function of the cold rolling reductionratio. The best formability properties after annealing are associatedto the higher cold deformation. This is a consequence of the texturedevelopment and through thickness homogeneity. The recristallizedgrains mis-orientation has been studied with the CSL approach andthe coincidence index.

Ultra and Very High Strength Steels (UHSS, VHSS) solutions are proposedby ArcelorMittal to meet front, side, rear and rollover crashrequirements. UHSS and VHSS steel monolithic solutions havestrongly progressed crash safety and lightening. Another steptowards higher performance is afforded by UHSS and VHSS TailoredWelded 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 solutionsis presented, in order to determinate the extra gains (i.e. masssaving, energy absorption) that a TWB solution can offer.