SURFACE-COATED DRILL EXCELLENT IN LUBRICATING PROPERTY AND WEAR RESISTANCE

摘要

PROBLEM TO BE SOLVED: To provide a surface-coated drill keeping high wear resistance over a long period of time even under such a drilling condition that a deep hole is formed wetly at a high speed.

SOLUTION: The surface-coated drill is obtained by forming a hard coating layer which comprises a (Ti1-xAlx)N component system as a particle size composition control layer and has a 0.3-5.0 μm thickness directly on a drill base comprising a cemented carbide sintered compact or high-speed steel or on the outermost surface thereof while interposing an intermediate layer therebetween and satisfies the following conditions (a), (b) and (c). The condition (a) is that the cross section of the particle size composition control layer of a margin part of the surface-coated drill has a layered high Ti content area of 0.1-0.2 Al content (x) and a layered high Al content area of 0.3-0.6 Al content. The condition (b) is that the aspect ratios A of crystalline grains in the high Ti content area are within 1-5. The condition (c) is that the aspect ratios B of crystalline grains in the high Al content area are within 10-70.

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