SURFACE-COATED CUTTING TOOL IN WHICH HARD COATING LAYER DEMONSTRATES EXCELLENT CHIPPING RESISTANCE AND EXCELLENT WEAR RESISTANCE IN HIGH-SPEED AND HEAVY CUTTING WORK

摘要

PROBLEM TO BE SOLVED: To provide a surface-coated cutting tool in which a hard coating layer demonstrates excellent chipping resistance and excellent wear resistance in the high-speed and heavy cutting work of a large black thickness-deviated component or the like.;SOLUTION: In a surface-coated cutting tool, a lower layer composed of a Ti compound layer (here, a modified TiCN layer is essential), and an upper layer composed of a modified Al₂O₃ layer are coated on a surface of a tool base body. A ratio GBLa/Ta of a grain boundary length GBLa (μm) measured on the TiCN layer having a longitudinally-grown crystalline structure to the measured layer thickness Ta (μm) of the modified TiCN layer is 275-520. Furthermore, a ratio GBLb/Tb of a grain boundary length GBLb (μm) measured on the modified Al₂O₃ layer having a columnar structure to the measured layer thickness Tb (μm) of the modified Al₂O₃ layer is 40-165. Still furthermore, a value (GBLb/Tb)/(GBLa/Ta) is in a range of 0.1 to 0.6.;COPYRIGHT: (C)2013,JPO&INPIT