| 摘要 |
The present invention relates to a cutting tool insert for side and face milling of rolled low alloyed steel at low and at moderate cutting speeds comprising a cemented carbide body and a coating and a method for making same. The cemented carbide body comprises WC, from about 7.3 to about 7.9 wt-% Co and from about 1.0 to about 1.8 wt-% cubic carbides of Ta and Nb and a highly W-alloyed binder phase with a CW-ratio of from about 0.86 to about 0.94. The coating comprises: a first (innermost) layer of TiC<SUB>x</SUB>N<SUB>y</SUB>O<SUB>z </SUB>with a thickness of from about 0.1 to about 2 mum, and with equiaxed grains with size less than about 0.5 mum a layer of TiC<SUB>x</SUB>N<SUB>y</SUB>O<SUB>z </SUB>with a thickness of from about 2 to about 10 mum with columnar grains with a diameter of about less than about 5 mum a layer of TiC<SUB>x</SUB>N<SUB>y</SUB>O<SUB>z </SUB>with a thickness of 0.1-2 mum and with equiaxed or needlelike grains with size less than about 0.5 mum an outer layer of a smooth, textured, finegrained alpha-Al<SUB>2</SUB>O<SUB>3 </SUB>layer with a thickness of from about 2 to about 10 mum. The invention also relates to the use of such a cutting tool insert for side and face milling of rolled low alloyed steel at low and moderate cutting speeds.
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