Free bending (or air bending) is a widely used brakebending
operation where the blank is supported at the outer edges without
being forced into a female cavity (as opposed to die bending). Thus,
the bending angle is determined by the ramstroke, not by the die
shape, see Kobayashi et al. (1989). This reduces the force demand
for forming. However, at the same time it gives rise to free surface
cracks and, if not, to relatively high springback. An analysis of
springback is beyond the aim of this study. In the following, first
the chemical composition and the microstructure of the utilized