ABSTRACT
The increase in tool life corroborates to the growth of productivity in manufacturing industries. In this context, the application of surface coatings is an alternative to increase the tool life of helical drills, especially those of small diameter. This paper studies the viability of plasma nitriding and duplex treatment on high speed steel drills. The studied nitriding treatments were performed at temperatures of 450 °C and 500 °C, while the duplex treatment was divided into conventional nitriding at 500 °C followed by the deposition of a TiN thin film applied by the cathodic cage plasma deposition technique at a temperature of 500 °C. The drills were characterized by Vickers Microhardness Test, Scanning Electron Microscopy (SEM), Energy Dispersion Spectroscopy (EDS) and Performance Simulation, where the flank wear on the cutting edge and the dimensional quality of holes machined in SAE 1045 steel specimens were measured. All treatments resulted in a higher surface hardness than that of untreated material. The tools subjected to nitriding and duplex treatment at 500 ºC presented underperformance, not showing viability for application under these conditions. The nitrided drill at 450 °C showed a longer tool life than the untreated drill and produced all holes within the limits set by the 9H12 tolerance. The study showed that the application of plasma nitriding at a temperature of 450 °C contributed to increase the tool life of high speed steel drills and to improve the dimensional quality of the holes.
Keywords
Plasma Nitriding; Duplex Treatment; High Speed Steel drills
