Wear behavior of CBN tool when turning hardened AISI D3 steel

Abstract

Investigations on wear resistance of cubic boron nitride tool during turning of hardened AISI D3 steel have been conducted. Initially, long term wear tests were planned to elucidating the effects of cutting speed on the various forms of CBN tool wear and also to make in evidence wear consequences on the tool life and the productivity. Then, a second series of experiments has been carried out to study the influence of wear (VB) on surface roughness, cutting force and temperature. Results show that the CBN tool presents a good wear resistance despite the aggressiveness of AISI D3 steel (60 HRC). A great part of heat generated during cutting is dissipated within the chip. Beyond 240 m/min cutting speed, the machining system becomes unstable, producing sparks and vibrations caused by intensive wear evolution. Meanwhile, up to the admissible wear value [VB] =0.3 mm, roughness Ra did not exceed 1 μm but beyond, roughness increased, but it remained extremely acceptable (Ra <1.2 μm). Finally, in one hand a mathematical model has been obtained to predict the tool life as a function of the cutting speed and in the other hand a correlation between roughness Ra and wear VB is proposed.