The element zinc, with a specific gravity of 7.0, is among the
heavier of the common structural metals. It is somewhat less dense
than iron (s.g. 7.7) and copper (s.g. 9.0). When used as a base
for die casting alloys, zinc is alloyed with aluminum, copper and
magnesium. Other elements present in the alloys are regarded as
impurities, and maximum limits, expressed as single numbers are
specified.
There are four alloys in the conventional zinc group, which are
often referred to commercially as the
“Zamak”
alloys (an acronym for zinc, aluminum, magnesium and copper). These alloys, with their ASTM designations, are:
Zinc 2 ASTM AC43A
Zinc 3 ASTM AG40A
Zinc 5 ASTM AC41A
Zinc 7 ASTM AG40B
