Patent attributes
An indexable insert (1) of the present invention includes a substrate (8) and a coating layer which includes inner layer and an outer layer. The inner layer includes an alumina layer or an alumna-containing layer serving as an outermost layer in contact with the outer layer, and the outer layer is composed of at least one metal selected from the group consisting of the periodic table group IVa elements, Va elements, and VIa elements, Al, and Si or a compound of at least one of the metals and at least one element selected from the group consisting of carbon, nitrogen, oxygen, and boron. In addition, the outer layer, in a portion involved in cutting, satisfies B/A≦0.9 wherein A μm is the average thickness on the flank face (3) side, and B μm is the average thickness on the rake face (2) side.
