Numerical study on the effects of main BCC rolling texture components on the formability of sheet metals

摘要

Crystallographic texture considerably affects the formability of crystalline materials. In this paper, the effects of BCC ideal rolling fibers-including alpha, oee-, eta, gamma, and xi fibers-on the sheet formability are numerically studied. The simulations are based on the numerical procedure developed by the authors in [1] in which a rate dependent crystal plasticity model along with the power law hardening are employed in a user material subroutine to model the behavior of crystalline materials. In order to determine FLD-in a M-K type approach-second-order derivative of sheet thickness variations with respect to time is used as necking criterion. The calculated FLDs of the fibers are compared with each other and with the FLD of isotropic condition. It was observed that in the case of gamma fiber a higher formability with respect to other fibers can be achieved in all regions of the curve. Also, alpha fiber, although weaker than other fibers at at right-hand side of FLD, shows higher formability at left. Finally, some suggestions are made based on FLD comparisons to improve sheet formability by controlling the texture produced in the manufacturing process.