CBN/PCD inserts are the best choice for high speed and precision machining of high hard material, difficult to cut material and cast irons. They can be used for machining normal gray cast iron with high speed, like engine cylinder and cover; Or machining alloycast iron and alloy cast steel, like roller, slurry pump; Or used for machining some tough material such as hardened steel, bearing steel and die steel; Or machining wear resistant alloycast iron like brake disc and brake drum; They also can be used for machining high temperature alloy like aeroengine.