The New Development of Tungsten Carbide Grade for Cutting Tools(5)
Nanometer coating technology has been dramatically developed in recent years ,its grain size general is under 100nm and has very good cutting performance. Japanese Sumitomo introduced super ZX coating grades(ACP200,ACP300,ACK300 and AC530U),which take thin coating layers with total mount 1000 ultra-layers of TiAlN and AlCrN overlapped on each other , each layer with thickness around 10 nanometers, as result the coating surface hardness and anti-oxidation performance are improved significantly .Comparing to the traditional TiAlN coating, the super ZX coating’s hardness is increased by 40%,and its initial oxidation temperature is risen by 200℃ ,in addition, its working efficiency is improved by 1.5 times and service life is prolonged 2 times in the same working condition. On the other hand ,Hitachi also introduced nanometer structure new coating grades such as ATH,ACS series grades ,which have higher hardness and anti-oxidation strength comparing to the common TiAlN(PVD) coating ,its oxidation resistance temperature reaches 1100℃and micro-hardness reaches HV3600 .They are available to dry-process materials from pre-harden steel to hardened steel.
It is also a new development trend for the coatings that to improve the costing surface roughness by means of fining grain size, so as to improve the coating tools friction and adhesion resistance performance. Mitsubishi from Japan introduced super-coating tungsten carbide grade UC6110 with patent technology for machining steel with high efficiency. The CVD coating on its rake face is consist of TiCN fining to nanometer which inhibition of grain growing and Al2O3 that inhibition of crystallization growing ,with very high toughness and wear-resistance, meanwhile its surface is coated with Ti metallic composition making surface very smooth. In addition, its flank face is black and ultra-smooth coating ,so as to keep wear stable .On the other hand ,Sumitomo introduced super FF coating grade(AC410K,AC610M,AC630M,ACP100,ACK200) ,which is only used on the tungsten carbide substrate with ultra-fine grain size TiCN,as result the binding strength between coating and substrate is improved significantly. In addition ,the ultra-fine and smooth FF Al-base file is coated on it ,resulting in its hardness improved by 30%,and surface roughness reduced by 50%.Meanwhile ,comparing with common materials ,its working efficiency is available to be increased by 1.5 times and service life is prolonged by 2 times.
