MACHINING Al_2O_3/6061Al METAL MATRIX COMPOSITES USING COATED TUNGSTEN CARBIDE INSERTS

摘要

An experimental procedure is used to machine 20 vol.% Al_2O_3/6061Al metal matrix composites using coated tungsten carbide cutting inserts in a finish turning operation. The turning operations were carried out at various cutting speeds and feed rates, at a constant depth of cut, and with the application of a coolant. Tool wear lengths at two locations, at the flank of the primary cutting edge and at the flank of the nose of the tool were measured for each cutting test after the removal of a predetermined volume of material. It was found that the wear lengths at both locations of the tool increased with a decrease in feed rate due to the increase in cutting time as the feed rate decreased. It was also found that for a given speed and feed rate the wear on the flank of the nose was higher than that of the primary cutting edge. This was attributed possibly to the presence of the built-up edge on the rake face of the tool. Surface roughness, generally, increased with an increase in cutting time that was explained in terms of an increase in nose wear length as the cutting time was increased.