Abstract
We observed the tool failure of three different kinds of cemented carbide tool in cutting plain cast iron. Weld was created at low speed on any tool, and some different types of tool failure were found at higher speed, that is, the tool with fine WC showed a rectangular type flank wear with deep crater and the coarse showed a triangular type with shallow crater. It being difficult to get the preferable rectangular type by cuttring such brittle cast iron, it is desirable that abnormal chipping does not appear. In this respect, the grade with both fine and coarse grains was preferable to the others.
Among the other factors affecting the failure, it was found that too small feed and relief angle accelerated the flank wear.
