Spheroidization rate is one of the important and often used evaluation criteria of ductile iron. The calculation method is as follows: firstly, the area ratio is obtained through Excel and formula, and then compared with the area ratio and spherical correction coefficient comparison table, each graphite is counted and classified, and then the spheroidization rate of each part can be calculated by substituting the result into the spheroidizing rate formula. The results were compared with the classification table of spheroidization rate.
Where:
η C — area ratio of graphite (%);
S — area of graphite ball (μ m2);
SD — minimum circumscribed area of graphite ball (μ m2).
Where:
η — spheroidization rate;
N1.0, n0.8, n0.6, N0.3, N0 — the number of graphite particles corresponding to the five correction coefficients.