Contact stresses on the rake face of cutting tools with PCBN in turning of hardened steel

Abstract

The paper presents the results of experimental study of determination of the geometric parameters of the contact zone of the chips with the rake face of cutting tools, as well as the shrinkage of chips during the final turning of hardened HVG steel by the tools from polycrystalline superhard materials with different contents of cubic boron nitride. Based on the experimentally established values of the cutting force components, a theoretical calculation of the level of maximum normal and tangential contact stresses for two types of tools: with high (BH) and low (BL) boron content has been conducted, and the nature of their distribution along the contact area of the chips with the rake face of the tools is shown. It is shown that during the turning of hardened HVG steel by the tool with composite of the BL group normal stresses up to 3.0 GPa arise in the contact zone and the tangential are 0,18 GPa at a cutting speed of 200 m/min, while turning by the tool with composite of group BH – 2,1 GPa and 0,58 GPa, respectively, at a cutting speed of 100 m/min.

Keywords

• cutting tool
• polycrystalline superhard composite
• cubic boron nitride
• chip shrinkage
• contact stresses
• turning
• hardened steel