| 摘要 |
PROBLEM TO BE SOLVED: To provide a drill made of diamond-coated cemented carbide having not only excellent chipping resistance but also excellent wear resistance in a long-term use in the overlap drilling or the like of CFRP and Al.SOLUTION: A drill made of diamond-coated cemented carbide includes a base body of WC-based cemented carbide mainly made of WC and Co, and containing 3-15 mass% of Co while a diamond film of an average film thickness of 5-30 μm is coated on the base body. A ratio of h1/h2 is ≥1.2 and ≤2.0 where h1 denotes the film thickness of an outer circumferential part of a cutting edge of the drill, and h2 denotes the film thickness of a chisel edge. Preferably, a value of w2 is ≥15 cm, and ≤25 cm, and a ratio w1/w2 is ≥0.5 and ≤0.9 where w1, w2 denote the half peak width of the peak around 1,333 cmat the Raman spectrometry of the outer circumferential part of the cutting edge and the chisel edge, respectively. More preferably, the ratio &sgr;2/&sgr;1 is ≥0.6 and ≤0.9 where &sgr;1, and &sgr;2 denote values of the compressive residual stress in the outer circumferential part of the cutting edge and the chisel edge, respectively. |
