PCBN Inserts are suitable for processing: 

1) Hardened steel and wear-resistant cast iron with hardness above 45HRC;

2) Heat-resistant alloy with above 35HRC;

3) Pearlitic gray cast iron with less than 30HRC, which other inserts could be used for machining;

4) PCBN tools are also suitable for hardened steel (45-65HRC), bearing steel (60-62HRC), high speed steel (>62HRC), tool steel (57-60HRC). 

5) High-speed semi-finished and finishining for chilled cast iron;

6) Capable of machining high temperature alloys, thermal spray materials, hard alloys and other difficult materials. 

The higher the hardness of the material being processed, the better the superiority of the PCBN tool.