La parution d’un nouvel ouvrage (1)de Gilbert Etienne, très intéressant commetoujours, nous amène, sans évidemmentvouloir refaire notre étude de 1990 (2),à faire le point de cette comparaisontoujours pour le domaine de la sidérurgie,près de vingt années plus tard.

Construction sector is the major user of Steel, and recyclingis very important for the sector itself and also for the Steelindustry, as a secondary raw material.
Recycling demonstrations of three building components (steelsandwich panels with polyurethane foam-steel compositestructures made of beams, profiled sheeting and reinforcementbars-steel profiles combined with plasterboard partitions)have shown that these steel components are easy to separateand produce a high quality scrap that ensure the profitabilityof this end-of-life treatment.

The feasibility of increasing proportion of lump ores in blastfurnace was investigated. The lab results showed that self-softeningand melting properties of the lump ores were dramaticallyimproved by interaction between sinters and lump ores foundin the experiments. Furthermore, the collocation pattern of lumpores and ratio between lump ores was optimized according tointeraction. When the proportion of lump ores was up to 23% or27% at the excellent collocation pattern and appropriate ratio,the burdens still conformed to the requirements of ironmaking.

Over the last decades the steel industries worldwide haveevolved more or less independently from each other, inthe EU and in North America in particular. A competitivecomparison of two different Basic Oxygen Furnace (BOF)maintenance operations is presented, discussing various costfigures in a theoretical case study.

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.

High cycle thermal fatigue due to the mixing of hot andcold fluids may initiate cracking in pipes of safety relatedcircuits. A method has been developed to identify suchfluid mixing zones subjected to potential thermal fatiguedamage. This method is based on a loading model and amechanical model that depend on the main characteristicsof the mixing zone and on the material properties. It issupported by a large experimental program. This methodhas been applied to all the mixing zones of safety relatedcircuits of the EDF pressurised water reactors, allowingto identify sensitive zones and to apply an appropriateinspection program that ensures the control of the risk dueto this damage mechanism.