The figure shows the graphite morphology of cast iron prepared under different vibration frequencies. Figures (a) – (d) show the graphite morphology of cast iron prepared at vibration frequencies of 0, 35, 50 and 100Hz respectively.
It can be seen from the figure that the vibration frequency has a significant effect on the graphite morphology of vermicular graphite cast iron. In the cast iron without vibration, the graphite morphology includes vermicular graphite and spheroidal graphite, which belongs to the typical graphite morphology characteristics of vermicular graphite cast iron, and the vermicular rate of vermicular graphite cast iron is high. When vibration is applied to vermicular graphite cast iron in EPC process, the graphite type changes from vermicular graphite without vibration sample to flake graphite. When the vibration frequency is, the graphite in cast iron is 35Hz flake graphite, and the length of flake graphite is longer; In the cast iron with a vibration frequency of 50Hz, the length of graphite between the primary dendrite arms is longer and the graphite has branches, while the length of graphite between the secondary arms is shorter; When the vibration frequency is further increased to 100Hz, the graphite length becomes shorter.