cBN SINTERED BODY FOR HIGH-QUALITY SURFACE PROPERTY MACHINING, cBN SINTERED BODY CUTTING TOOL, AND METHOD OF CUTTING WORK THEREWITH

摘要

A sintered body with high cBN content that as compared with conventional cBN sintered body tools, inhibits the occurrence of machining affected layer on a machining plane of machinable material and promotes the retention of compressive stress to thereby attain prolongation of the fatigue life of machined parts and also realize prolongation of the tool life. There is provided a cBN sintered body for high-quality surface property machining characterized in that the topmost surface of cBN sintered body (1) containing, by vol.%, 87 to 99% of cBN component and having a thermal conductivity of 100 W/m·K or higher is coated with 0.5 to 12 µm thick thermostable film (2) constituted of a compound of at least one element selected from among Group 4a, Group 5a and Group 6a elements and Al and at least one element selected from among C, N and O.