In reply to Craig:
I doubt there is any real difference as far as you and I are concerned.
In cold forging the the thing is hit at room temperature and deformed into the required shape. In so doing it gains strength through cold working with some possible loss of ductility (strain to failure or elongation) this shouldn't matter as the base material will be chosen with plenty to spare.
In the hot process the component is heated before it is hit. The benefit of the hot process is that it requires less oomph as hot things have a lower strength than things at room temperature. Being hot also allows better flow of the materials grains resulting in a "better" microstructure. Hot processes may result in a lower strength and better ductility than a cold process unless there is some post manufacture heat treatment or controlled cooling. Again this won't matter with krabs from a good supplier as they will pick an appropriate material grade to start with.
The terms hot and cold need to be interpreted with care, particularly the hot one. Hot really refers to temperatures at which certain metallurgical changes occur even for Aluminium this is hot. Some so called hot processes are actually warm, above room temp but below the temp for metallurgical change.
Hope that helps a bit.
