| 摘要 |
The present invention discloses a cutting tool insert particularly for deep hole drilling comprising a cemented carbide body and a coating. The cemented carbide body is WC, from about 8 to about 11 wt-% Co and from about 0.1 to about 0.5 wt-% Cr with an HcJ-value of from about 18 to about 22 kA/m and with a CW-value of from about 0.78 to about 0.90. The coating comprises a first, innermost layer of TiC<SUB>x</SUB>N<SUB>y</SUB>O<SUB>z </SUB>with equiaxed grains with size and a total thickness of from about 0.1 to about 1.5 mum, a layer of TiC<SUB>x</SUB>N<SUB>y </SUB>with a thickness of from about 2 to about 3 mum with columnar grains, a layer of a smooth, fine-grained kappa-Al<SUB>2</SUB>O<SUB>3 </SUB>with a thickness of from about 1 to about 2.5 mum and an outer layer of TiN with a thickness of from about 0.5 to about 1.0 mum, where the outermost layer of TiN is missing along the cutting edge.
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