If you’re looking for an industrial or heavy duty caster, you’ve no
doubt come across the term Semi Steel. And, unless you have a
background in metallurgy, chances are you’re not sure what it is.
As it turns out, semi steel is actually a type of cast iron, with steel
scrap thrown in the mixture for good measure. In fact, most semi-steel
has quite a bit of steel scrap in it. The result is an alloy that is
excellent for use as caster wheels, for a variety of reasons. Semi steel
features easy castability, low cost, and machinability, just as cast
iron does. It also has added strength, impact resistance, and ductility
from the steel. This makes semi-steel a perfect balance of cost
effective strength for many medium and heavy duty casters.