CNGN CBN Inserts Application Case IT700- for rough turning Brake Disc For example: Workpiece: Brake Disc Material: HT200 Hardness: HB170-210 Insert: CNGN120408 Cutting parameter: Vc=580m/min ap=2mm f = 0.35mm/r For comparison only: The tool life is 2â??3 times than normal coated alloy inserts.