US Patent 7135221 Coated cutting insert for rough turning

A cutting tool insert with a cemented carbide and a coating. The cemented carbide substrate includes WC, 7 to 12 wt-% Co, 5 to 11 wt-% cubic carbides of metals from the groups IVb, Vb and VIb with a binder phase that is highly alloyed with cobalt. The tungsten carbide phase has a mean intercept length of 0.7 to 1.4 μm. The coating includes at least one 2 to 12 μm thick α-Al2O3 layer composed of columnar grains with texture coefficients: TC(012)>2.2 and TC(024)>0.6×TC(012).