STRENGTH FEATURES OF HARDENED STEEL TREATMENT BY TOOLS EQUIPPED WITH PcBN OF BH, BL GROUP

A set of studies has been carried out to investigate the power features of machining hardened steel with a tool equipped with PcBN of the VN group, obtained from the initial cBN powders coated with Ti and uncoated compounds, as well as PcBN of the BL group. The determined features of the machining process have shown that the wear of the cutting tool has a significant impact on the value of the cutting force components – when cutting at a speed of 350 m/min, the machining process with a tool of PcBN group BH obtained from coated powders, compared to machining with a tool of PcBN group BH obtained from uncoated powders, is characterized by a 15–20% lower value of the cutting force components. During high-speed machining under dynamic shock loads, a tool equipped with BH PcBN obtained from coated cBN powders, unlike cutters made of BL PcBN, retains its performance at a feed rate of 0, 38 mm/rev - usually, working under such conditions leads to brittle fracture of the tool equipped with PcBN of group BL due to chipping of individual fragments of the cutting edge from the back surface, and on the tool equipped with PcBN (5% Ti), there are separate traces of microchipping. The obtained research results indicate the possibility of using tools equipped with PcBN of group BH, sintered from coated cBN powders, under high-speed cutting conditions, which is typical for tools made of PcBN of group BL, but in the presence of dynamic loading.