Investigation of the strain-hardening behaviour of modern lightweight steels considering the forming temperature and forming rate
New lightweight steels for auto-body components have been developed to satisfy the requirements of improving passive safety, weight reduction and energy saving as well as economic mass production. Examples of these steel groups are Dualphase, TRIP and TWIP steels, which have been developed and improved by making use of microstructure design and strain-induced phase transformations. In all these steels high strength values in combination with an increase of ductility and toughness have been reached by increasing the strain-hardening behaviour. Therefore, in this project the strain-hardening behaviour has been investigated as a function of temperature, strain rate and stress state by several types of mechanical tests. The different steels were strained by tensile tests at different temperatures and strain rates (up to 1 000s-1), bulge tests and simple shear tests for the determination of the dependence of the different forming conditions on the flow curve properties. Formability studies have also been performed in laboratory samples and some components by cupping tests, the determination of FLDs and component crash tests. The influence of the different microstructure concepts on the strain-hardening behaviour has been investigated by quantitative microstructure analysis of the materials in deformed as well as in non-deformed condition. In order to foster prediction of material behaviour for each steels group, existing models for the description of the strain-hardening behaviour have been evaluated and improved. FE simulations of experimental tests making use of the different material models helped on this topic.
Bibliographic Reference: EUR 23599 EN (2008), 148 pp. Free of charge
Availability: Catalogue Number KI-NA-23599-EN-S The PDF version can be from: http://bookshop.europa.eu
ISBN: ISBN 978-92-79-10007-9
Record Number: 200910401 / Last updated on: 2009-10-07
Original language: en
Available languages: en