Abstract
The fact that the nitrogen contained cermets tools show a higher chipping resistance of cutting edge would widely be accepted. However, the reason appeared not to have been clarified until now. Then, the study on this subject was undertaken in dry milling tests of TiC-(0-40) vol%TiN-10vol%Mo2C-10vol%Ni cermets tools. It was found that the deformation of cutting edge during the tests was suppressed in nitrogen contained tools with increasing nitrogen content, this leading to the decrease in the number of fine cracks forming mainly perpendicular to cutting edge. In short, the higher chipping resistance of nitrogen contained cermets tools was attributed to the superior creep strength of those cermets, being in no relation to their thermal properties, etc.
