Hi,
Most of the machine tool beds are made of gray cast iron or modified cast iron. It has a very good damping capacity, which during the manufacturing process results in high accuracy of the object.
It is a high carbon alloy of iron with carbon , usually also with silicon, manganese , Sulphur and other ingredients.
Contains 2.11 to 4.3% carbon in the form of graphite or cementite.
Hope it helps....