Patent attributes
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 TiCxNyOz with a thickness of from about 0.1 to about 2 μm, and with equiaxed grains with size less than about 0.5 μma layer of TiCxNyOz with a thickness of from about 2 to about 10 μm with columnar grains with a diameter of about less than about 5 μma layer of TiCxNyOz with a thickness of 0.1-2 μm and with equiaxed or needlelike grains with size less than about 0.5 μman outer layer of a smooth, textured, finegrained α-Al2O3 layer with a thickness of from about 2 to about 10 μm.
