SURFACE COATED CUTTING TOOL HAVING HARD COATING LAYER EXHIBITING EXCELLENT CHIPPING RESISTANCE IN HIGH-SPEED CUTTING OF DIFFICULT-TO-CUT MATERIAL

摘要

PROBLEM TO BE SOLVED: To provide a surface coated cutting tool having a hard coating layer exhibiting excellent chipping resistance in the high-speed cutting of a difficult-to-cut material. SOLUTION: A hard coating layer of the surface coated cutting tool is composed of two layers whose the lower one is formed of a Ti compound layer, and the upper one is formed of a reformedα-type Al2O3layer and a standardα-type Al2O3layer. On the reformedα-type Al2O3layer, when the inclination angle formed of a normal to a (0001) face which is the crystal face of a crystal grain is measured by a scanning electron microscope of a field emission type, and an inclination frequency distribution graph is drawn, the graph shows a peak within an inclination section of 75-85 degrees and the sum of frequencies existing within a range of 75-85 degrees occupies 45-65% of the whole frequency. Surface roughness shows Ra:0.2μm or smaller. COPYRIGHT: (C)2008,JPO&INPIT