| 摘要 |
PROBLEM TO BE SOLVED: To provide a surface coated cemented carbide throw-away tip whose cutting edge part exhibits superior chipping resistance. SOLUTION: In this surface coated cemented carbide throw-away tip, on the surface of tungsten carbide base cemented carbide throw-away tip, having a composition such that as a binder phase forming component, 4 to 20 mass % Co and 0.1 to 4 mass % Cr, and the residue is formed by tungsten carbide and inevitable impurities as a hard phase forming component, in which in the measurement by longitudinal section texture observation using an optical microscope, a porous band area where vacancy exists in a ratio of 5 to 30 area % is existent in the cutting face part including a cutting edge ridge line part where the cutting face and flank of the cutting edge part intersect each other extending from the surface to a depth of 20 to 10μm, and the vacancy ratio of the other body part is 2 area % or less, a composite nitride layer of Ti Al satisfying a composition formula: (Ti1- XAlX)N(wherein at atom ratio, X is 0.15 to 0.65) is physically evaporated as a hard coating layer with an average layer thickness of 1 to 20μm.
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