Excellent surface coating drill in wear resistance and chip discharge performance

摘要

PROBLEM TO BE SOLVED: To increase a life of a surfaced coat drill which exhibits excellent abrasion resistance and chip disposal properties when used for the deep drilling of carbon steel.;SOLUTION: (1) In the surface coated drill coated with a composite acid nitride layer composed of a component system of (Ti_1-x-yAl_xSi_y)(N_1-zO_z) (where x=0.40-0.70, y=0.01-0.10, and Z≤0.4 in terms of atom ratio) having an average layer thickness of 0.8-5.0 μm on a drill substrate, the coated layer gradually increases in oxygen content from a drill forefront part toward a shank, also (2) an average long diameter continuously increases from a fine grained crystalline structure to a pillared crystalline structure, and an average aspect ratio of the crystal grain structure increases gradually, and (3) since an average surface roughness Ra decreases gradually, such an interface is not present that heat characteristics and machine characteristics are extremely changed along a drill axial direction as inducing cracks by a cutting shock.;COPYRIGHT: (C)2013,JPO&INPIT