SURFACE-COATED CUTTING TOOL HAVING THEREIN HARD COATING LAYER CAPABLE OF EXHIBITING EXCELLENT CHIPPING RESISTANCE DURING HIGH-SPEED INTERMITTENT CUTTING WORK

摘要

A surface-coated cutting tool includes a body and a hard coating layer coating the cutting tool body. In the surface-coated cutting tool, the (Ti 1-X Al X )(C Y N 1-Y ) layer with a cubic crystal structure (X and Y are atomic ratio, and satisfy 0.60‰¤X‰¤0.90 and 0.0005‰¤ Y‰¤0.005, respectively) is vapor-deposited on the body by a chemical vapor deposition method. The Al content X L is 0.55‰¤X L ‰¤0.70, and the grain size D L is 0.1 µm or less in the (Ti 1-X Al X )(C Y N 1-Y ) layer near the interface between the body and the complex carbonitride layer. The Al content X H 0.80‰¤X H ‰¤0.95 and the average grain size D H is 0.5 µm to 2 µm in the (Ti 1-X Al X )(C Y N 1-Y ) layer near the outer surface side. Furthermore, the Al content ratio and the grain size in the (Ti 1-X Al X )(C Y N 1-Y ) layer gradually increase to the outer surface side.