... HB about 200, high hardness cast iron with HRC50-64 and so on! Harden steel with HRC50-67, Cutting speed, ... about 0.2mm General gray cast iron with HB about 200, Cutting speed, 500-1000 m/min; Feed, 0.1-0 ... .5; Cutting deepth, about 3.0mm High hardness cast iron with ... Cutting speed, 50-100 m/min; Feed, 0.1-0.3 mm/rev, Cutting deepth, about 2.5mm CBN inserts for cutting tool