CUTTING TOOL MADE OF SURFACE COATED HIGH-SPEED TOOL STEEL HAVING HARD COATING LAYER EXHIBITING SUPERIOR WEAR RESISTANCE IN HIGH-SPEED CUTTING OF HIGH HARDNESS STEEL

摘要

PROBLEM TO BE SOLVED: To provide a cutting tool made of a surface coated high-speed tool steel having improved tool life.;SOLUTION: The cutting tool made of the surface coated high-speed tool steel is formed by vapor-depositing a hard coating layer composed of an upper layer and a lower layer made of (Cr, Al, Si) N on the surface of a substrate of high-speed tool steel, wherein the upper layer has an average layer thickness of 0.5 to 1.5 μm and the lower layer has an average layer thickness of 2 to 6 μm respectively, the upper layer has an alternately laminated structure of a thin layer A and a thin layer B having one layer average layer thickness of 5 to 20 nm (nanometer) respectively, the thin layer A is formed of (Cr, Al, Si) N layer satisfying a specified composition formula: [Cr_1-(A+B) Al_A Si_B] N, and the thin layer B is formed of (Cr, Al, Si) N layer satisfying a specified composition formula: [Cr_1-(C+D) Al_C Si_D] N, the lower layer has a single phase structure, and is formed of (Cr, Al, Si) N layer satisfying a specified composition formula: [Cr_1-(E+F) Al_E Si_F] N.;COPYRIGHT: (C)2007,JPO&INPIT