SHINDE Subodh ArcelorMittal

Recent Developments in the Use of Quenched and Self-Tempered Hot Rolled H-Beams

Co-authors MAY Marc

The quenching and self-tempering (QST) installation at the ArcelorMittal heavy sections rolling mill of Differdange (Luxembourg), developed in collaboration with the Centre de Recherches Métallurgiques (CRM) in Liège (Belgium), is in industrial operation since more than 20 years. The possibility of combining high strength with outstanding welding properties, besides a high ductility and good through-thickness properties, made heavy ‘jumbo sections’ in QST steels an immediate success in specific construction applications. QST steels are considered conventional structural steels and are known in the market as HISTAR (High-Strength-ArcelorMittal) grades. They are covered by EN and ASTM standards. Eurocode 3 (EN 1993) also takes into consideration these new high strength steels by proposing specific design parameters and buckling curves. Sections made of QST steel have become an integral part of sophisticated applications such as the American ‘strong column-weak beam’ concept for high-rise structures in seismic areas as well as for members of offshore structures. Latest research projects cover topics such as the behaviour of high strength QST steels during galvanisation and the improvement of weld design parameters. Research has also been performed on asymmetrically fabricated castellated beams (ArcelorMittal Cellular Beams) where QST steels are used especially in the parts where their full strength can be activated as well as high performance composite structures combining H-beams in QST grades with high strength concrete. This paper summarises the latest developments in research projects aimed at optimising design parameters and the improvement of the efficiency in new applications of QST beams.