| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a surface coated drill that maintains high wear resistance and chip discharge property over the long period of time in the wet process high speed drilling machining condition of an alloy steel. <P>SOLUTION: The surface coated drill forms a composition hardness control layer to the outermost surface on a drill base that consists of a cemented carbide sintered body or a high-speed steel directly or via an intermediate layer, wherein the composition hardness control layer consists of a component system of (Ti<SB POS="POST">1-x</SB>Al<SB POS="POST">x</SB>)N and has a layer thickness 0.3-5.0 μm, and in the component system, when the content ratio of Al to the whole metallic elements is made x, the content ratio of Al at the drill tip exists in x=0.3-0.5, and the content ratio of Al at the margin part at the position of three times of a drill diameter from the drill tip exists in x=0.5-0.7, and the content ratio x of Al gradually increases from the drill tip to the position of three times of the drill diameter, thereby the problem is solved. <P>COPYRIGHT: (C)2013,JPO&INPIT |
