Is usually expected, higher hardness and higher wear resistance of cutting material must be regarded a higher wear resistance cast iron. And in truth includes the really difficult material TiC (titanium carbide) or TiCN (titanium carbonitride) thick coating within the cutting speed of 300 meters per minute when the processing of iron proved frequently successful. But together with the increase of cutting speed, the chip / tool mixture of surface temperature is increasing. When that takes place, TiC coating and the iron tends to react chemically and softening, more pressure to the crater wear resistance from the coating. Under these conditions, I hope there is a superior chemical stability from the coating, including Al2O3 (despite the fact that at a reduced speed than TiC difficult or wear).