The lubricant forced out of these pressure areas or cavities during forming produces
locally limited hydrodynamic friction states. The tendency of one surface
to become bonded by galling and seizing on direct contact with the other surface
is a major problem in cold-forming operations. The chemical and physical-chemical
properties of the surfaces of the tool and workpiece have a considerable influence
on the tendency to galling and seizing. Under favorable conditions the
workpiece surface can be altered to such an extent that galling and seizing during
the cold-forming process practically never occur. To achieve this is one of the
main aims of chemical surface treatment.