Structure-related properties of a material to absorb applied mechanical oscillation energy.
Lamellar graphite cast iron (GJL types) has the highest damping capacities by far. It achieves values which can be 100 times higher as those of other types of steel. Thus, these materials our predestined for components with noise development being a major issue, which are, however, subjected only to low mechanical stress. This includes machine beds and supports, as well as cylinder blocks and brake components and many types of gearboxes.
The damping capacity of lamella graphite cast iron is highly influenced by the amount, shape and size of the graphite in the structure. The larger the amount and the rougher the precipitations, the higher the damping capacity. The behavior of strength is just the opposite: it decreases with increasing graphite content and with increasing lamella size. The damping capacity is inversely proportional to the elastic modulus.
The specific damping capacity of iron-carbon materials is as follows:
Annealed copper-manganese alloys have even higher damphing capacities.