Abstract:The ingot including impurity of YG8 cutter hard alloy was made by the measure of VAR. Φ40 mm
bars were made from ingot by forging and the position of impurity was located by ultrasonic detection. The appearance
of impurity was observed through optical microscope and SEM. The results show that hard alloy melts partially and the
boundary has transition area. The transition area includes elements of titanium and elements of cutter hard alloy,
where diffusion happens. The existence of impurity leads to stress focus which produces fatigue flaw easily, then influ-
ences the quality of product.