If a material is
isotropic, then 
= 1. For
deep drawing, we want as large as
possible. In practice is
between 0.8 and 1.2 for a non-textured rimming steel, and between 1.5 and 1.8 for an
Al-killed steel.
Not only is it important for to
be large, but we want to minimise wastage through "earring" during the deep
drawing process. An indication of the amount of earring is given by Dr, where:
If Dr
is close to zero, then the steel shows little tendency for earring.
