Explain why a metal with a fine-grain microstructure
is better suited for fine blanking
than a coarse-grained metal.
A fine-blanking operation can be demanding;
the clearances are very low, the tooling is elaborate
(including stingers and a lower pressure
cushion), and as a result the sheared surface
quality is high. The sheared region (see Fig. 7.6
on p. 353) is well defined and constrained to
a small volume. It is beneficial to have many
grain boundaries (in the volume that is fracturing)
in order to have a more uniform and
controlled crack.
