Abstract
Damping capacity, besides tensile strength, is one of the important mechanical properties of cast iron. Damping capacity measurement was made of various cast irons and steels and the reason for the high damping capacity of grey cast iron was discussed in the light of the experimental results. In the first stage of the experiment, the damping capacity of cast iron was found to be almost unchanged with the carborn content up to 3%, but to increase sharply beyond this percentage owing to the mass effect of carbon. In the second stage of the experment, the damping capacity of grey cast iron, meenhanite metal, nodular cast iron, matalleable cast iron, and cast steel was measurd and found to be highly dependent on the graphite shape in the material. The more spherial the graphite in a cast iron, the lower was its damping capacity. Damping capacity was critically dependent on the strain ampltude used in the test. A hystresis phenomenon was observed at high strain amplitudes. The above two effects were most pronounced with cast iron with flaky graphite. The high damping capacity of grey cast iron was attributed to dislocation movement due to stress concentration at pointed edges of graphites. In the third stage of the experiment, stress-strain curves in suport of the hypothesis were obtained from bending tests.
