Flexible coupling is a pipe connecting device is equipped with vibration damping piping system. One example of flexible coupling on the market is victaulic flexible coupling type 75. To determine the quality of flexible coupling, to be known mechanical properties and micro structure of the material. Tests conducted include hardness testing, chemical composition testing and metallographic.
Test results showed that the material used as a flexible coupling it is nodular cast iron, (ductile iron). Hardness values for ductile iron 172.9 BHN, while the tensile strength value about 596.59 MPa obtained by converting the value of hardness of the material. From the metallographic testing is known that ferrite content is more dominant than the pearlite will enhance the material toughness. The element carbon is more than usual ductile iron standards of more than 4.584% so that the hardness will increase the value of flexible coupling
