Special features of the applications of cutting tools from polycrystalline cubic boron nitride with protective coatings

Abstract

The results of the investigations on the efficiency of cutting tools from polycrystalline superhard materials based on cubic boron nitride with a protective coating. A hypothesis is proposed for the increase of the cutting tool life in turning hardened steel due to a decrease of the temperature in the cutting zone and a complex of physico-mechanical properties of the protective coating required for this is analyzed. A protective coating of boron nitride is considered in the amorphous state that plays a role of a solid lubricant in the zone of the tool contact with cutting chips, decreases the temperature in the contact zone through the reduction of the contact length and cutting force, ensures an increase of the tool life and reliability, especially at the stage of the run-in.