Community Research and Development Information Service - CORDIS


Final report on Contract no. 7210-PR/044, 1 July 1997 to 31 December 2000

Multi-phase steels, like dual-phase (ferrite- martensite) ones, require accurate models for prediction of their properties and for a better understanding of their behaviour. The finite element technique with simulation of microstructures is proved to allow modelling the behaviour of these steels, as well as the local deformations, once optimal conditions are determined. Among other advantages, various behaviour laws can be used for the different phases constituting the steel. Experimental work has been done to optimise conditions of producing cold-rolled DP steels and also to obtain data to validate our calculations. The effect of different compositions and thermal treatments on the microstructures and tensile properties has been tested. A good prediction capacity of the models can be obtained if sufficient attention is paid to determining the individual phase behaviour laws, taking into account the local compositions. Several methods are proposed for this purpose. In particular, the nanoindentation technique has been investigated; this method gives very local information, but requires a fine analysis to obtain macroscopic strength. The FEM technique also allows the taking into account of various morphologies as well as the initial stress state in the product. Strain-gradient-dependent plasticity theory, based on geometrically necessary dislocations, allows the prediction of the effect of the structural size on strength and work hardening in a very natural and efficient way. Finally, a simplified model based on the self-consistent method with modified secant linear extension is proposed.

Additional information

Authors: BUESSLER P, IRSID, Maizières-lès-Metz (FR);BOUAZIZ O, IRSID, Maizières-lès-Metz (FR);IUNG Th, IRSID, Maizières-lès-Metz (FR);GIL SEVILLANO J ET AL, CEIT, San Sebastián (ES);VRIEZE J, Corus RD&T IJTC, IJmuiden (NL);KALUZA W, IEHK, RWTH, Aachen (DE)
Bibliographic Reference: EUR 20331 EN (2002), pp.206. Euro: 31.00
Availability: Available at (EU Book Shop), Catalogue Number: KI-NA-20-331-EN-S
ISBN: ISBN: 92-894-3660-3
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