Wear characteristics of nano TiAlN-coated carbide tools in ultra-high speed machining of AerMet100

Abstract

In this paper cutting experiments of AerMet100 (52 HRC) using nano TiAlN-coated carbide tools with cutting speed from 250m/min to 7000m/min are carried out. The cutting tool wear characteristics under ultra-high cutting speeds are examined and the corresponding mechanisms are analyzed. The focus is put on the tool wear characteristics and mechanisms at cutting speed above 500m/min. The influences of cutting temperature and workpiece dynamic mechanical properties on tool wear are discussed. The results show that the tool wear mechanism is highly influenced by cutting temperature and workpiece mechanical properties. At cutting speed of 500m/min the dominate wear mechanism is micro chipping and fracture due to the cutting force vibration and cold welding of contacting materials between cutting tool and workpiece. At higher cutting speed from 1000m/min to 7000m/min the predominant tool wear mechanisms are abrasion, adhesion, and fracture due oxidation, and thermal softening, and grooving by hard grains. The roughness of tool flank at this cutting stage decreases with the increase of cutting speed due to the high thermal softening. The increase of workpiece material brittleness with the increase of cutting speed lowers the elastic rebound of machined surface and reduces the tool wear rate.