CUTTING TIP OF CUTTING EDGE REPLACEMENT TYPE

摘要

An indexable insert (1) includes a substrate (8) and a coating layer formed on the substrate. The coating layer includes an inner layer and an outer layer. The inner layer is constituted by a layer containing at least one element selected from the group consisting of Group IVa elements, Group Va elements, and Group VIa elements in the periodic table, and Al and Si. The uppermost layer of the inner layer in contact with the outer layer is composed of a compound at least containing Ti and at least one of nitrogen and boron. The outer layer is constituted by an alumina layer or an alumina-containing layer. In a region involved in cutting, the outer layer satisfies B/A ‰ 0.9 where A µm is the average thickness at the flank face (3) side and B µm is the average thickness at the rake face (2) side.