Procedure for the Experimental Determination of a Forming Limit Curve for Usibor 1500 P
Résumé
USIBOR 1500 P® is a coated C-Mn steel, micro-alloyed with boron, with excellent processing properties in hot stamping, both in terms of formability, quenchability and surface protection, and leading to superior mechanical properties on the formed part. Arcelor Research is developing a numerical tool to support the feasibility analysis and to optimize the design of hot stamped parts made of USIBOR 1500P®. Among the numerous bricks of such a simulation methodology, formability data of the material are of primary importance as the forming analysis relies on them to make a decision in terms of feasibility. Up to now, there was no experimental procedure available in literature to determine the forming limits of hot stamping material, taking into account the specificities of this process. This paper reports about the research performed in this field. First, an efficient experimental set-up which allows varying all the desired process conditions has been developed. Several hundred Nakazima hot stamping tests have been carried out for various process parameters (stroke, velocity, friction and heat exchange) and blank para-meters (temperature, thickness and shape). The third step consisted in developing and vali-dating an accurate analysis scheme to determine the critical strain values based on the Bragard method. Finally, the critical strain values have been confirmed and comparisons with industrial parts for various process conditions have been performed. In this paper these two last steps are mainly presented.
Domaines
Matériaux
Origine : Fichiers produits par l'(les) auteur(s)
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