The grade of vermicular graphite cast iron is: rut + Digital.
In the brand, “rut” is the capital prefix of the Chinese Pinyin of the word “vermicular iron”, which is the code of vermicular cast iron; The following number indicates the minimum tensile strength. For example, the brand RuT300 represents vermicular cast iron with a minimum tensile strength of 300mpa.
Figure 1 ~ 3 show the graphite morphology of gray cast iron, vermicular iron and nodular iron respectively. It can be seen that the graphite of vermicular iron is between flake and spherical. The graphite of vermicular iron is short and thick, with round ends, which looks like a worm. By observing the three-dimensional morphology of vermicular graphite under electron microscope, it can be seen that the end of graphite has the obvious characteristics of spiral growth, which is similar to the spherical surface morphology. However, the branches of graphite have laminated structure, which is similar to flake graphite. Its compactness is also between flake and spherical. There is a proportional relationship among flake, vermicular and spherical graphite: the ratio of length L to thickness d of flake graphite is l: d > 50; General vermicular graphite L: D = 2 ~ 10; Spheroidal graphite L: D ≈ 1.