| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a surface coated drill that maintains high wear resistance over the long period of time in the drilling condition for a deep hole of wet process high speed. <P>SOLUTION: In the surface coated drill in which a hard coating layer consisting of a component system of (Cr<SB POS="POST">1-x</SB>Al<SB POS="POST">x</SB>)N and having a layer thickness of 0.3-5.0 μm exists at the utmost surface on a drill base consisting of a cemented carbide sintered body or a high-speed steel as a grain size composition control layer directly or via an intermediate layer, (a) the value of the content ratio x of Al at the film cross section of the grain size composition control layer of the margin part of the drill exists in the range of at least 0.1 and at most 0.6, and a layer shape Cr high content region in which the value x becomes at most 0.2 and a layer shape Al high content region in which the value of x is at least 0.3 exist, and (b) the average aspect ratio A of the crystal grain in the Cr high content region is 1-5, and (c) the average aspect ratio B of the crystal grain in the Al high content region is 10-70, thereby the problem is solved. <P>COPYRIGHT: (C)2013,JPO&INPIT |
