Although the application of ductile iron and vermicular graphite cast iron is on the rise, the application of gray cast iron is still strong. In the automotive industry, large amounts of gray iron processing (especially brake drums and brake discs) will also be retained. However, today’s processing conditions have changed from the past, the cutting speed has been increased by about 305m / min over 10 years ago. The higher temperatures created by high-speed machining can dissolve the cutting insert’s hard coating in much the same way as the chemical reactions between PCBN and ferrite. To prevent the coated cemented carbide from being damaged and to prevent cutting heat from entering the substrate, tool makers are continually increasing the thickness of the alumina layer in the tool coating. In addition, it is even more important to improve the structure of these multilayer coatings to provide them with better toughness and wear resistance.
High temperature processing of gray cast iron (cutting speed up to 550m / min) and specially designed new heat-resistant grades have been put on the market. These multi-layer coatings for high-speed cutting include an aluminum oxide (Al2O3) thick coating and a high hardness titanium carbonitride (TiCN) layer (which enables the tool to maintain high abrasion resistance for a long time to improve productivity) . In the on-site machining trials with the new coated heat-resistant grades of gray cast iron brake disc parts (cutting speed range: 400-658 m / min), the tool life was doubled compared to using silicon nitride ceramic inserts, Productivity increased by 20%. This increase in productivity is due to the better cutting edge toughness of the heat-resistant grades, allowing them to use higher feed rates than ceramic inserts.
In summary, all of these factors add to the need for superior performance cutting tools that require these tools to process higher strength, more abrasive workpiece materials, higher cutting speeds, and consistent tooling LIFE AND QUALITY OF THE PARTS – This is a very demanding requirement for one blade.