Vermicular graphite cast iron is a gray cast iron with a transitional form between flake and spheroidal graphite. It is a new type of engineering structural material characterized by good 

mechanical properties and thermal conductivity and low cross-sectional sensitivity.

Because vermicular graphite cast iron has the properties of both ductile cast iron and gray cast iron, it has unique uses and has achieved good results in applications such as ingot molds, 

automobile engines, exhaust pipes, glass molds, diesel engine cylinder heads, and brake parts.

However, for mechanical processing, it adds new difficulties. There has been no particularly ideal processing tool. Many customers have begun to try to use CBN to test and process vermicular 

graphite cast iron.

Whether vermicular graphite cast iron can be processed with CBN depends on the pearlite content in the metallographic structure of vermicular graphite cast iron. If the pearlite content of 

vermicular graphite cast iron exceeds 90%, PCBN tools can be used for testing; otherwise, PCBN tools cannot be used, and it is more cost-effective to continue to use alloy tools.

The as-cast matrix structure of vermicular iron is characterized by a high ferrite content (40% to 50% or higher), but pearlite stabilizing elements (such as copper, tin, antimony, etc.) can also be 

added to obtain a cast pearlite matrix, the content of which is about 70%. The pearlite matrix can also be obtained by normalizing treatment.