| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a surface coated cutting tool whose hard coating exhibits superior chipping resistance during high-speed, intermittent cutting. <P>SOLUTION: The surface coated cutting tool has the hard coating, comprising a lower layer (a Ti compound layer) and an upper layer (an Al<SB POS="POST">2</SB>O<SB POS="POST">3</SB>layer), that has been formed by deposition upon a surface of a tool base formed of a WC-based cemented carbide or a TiCN-based cermet. The ratio b/a of the crystal grain count b on the Al<SB POS="POST">2</SB>O<SB POS="POST">3</SB>layer side to the crystal grain count a on the Ti compound layer side, is in a range of 0.8<b/a<1.2 in a cutting edge, and is in a range of 4<b/a<20 in flank and rake faces, both side grains being present on the adjoining interface between the lower layer and the upper layer. Additionally, the crystal grains in the Ti compound layer directly beneath the Al<SB POS="POST">2</SB>O<SB POS="POST">3</SB>layer have a mean grain size of no more than 0.1 μm in the cutting edge, and have a mean grain size in a range of 0.1 to 0.5 μm in the flank and rake faces. <P>COPYRIGHT: (C)2012,JPO&INPIT |
