Coated cemented carbide endmill

摘要

The present invention relates to a cemented carbide endmilling tool for semifinishing and finishing machining of hardened steels of HRC above 46, comprising a substrate and a wear resistant coating comprising a substrate and a wear resistant coating. The substrate, a, comprises 90-94 wt% WC in a binder phase of Co also containing Cr in such an amount that the Cr/Co weight ratio is 0.05-0.18. The wear resistant coating, b, is 1.8-9.5 µm thick, and comprises a first layer, c, of a hard and wear resistant refractory PVD AlMe nitride or carbonitride where Me is Zr, V, Nb, Cr or Ti having a thickness of 1.0-4.5 µm and an atomic fraction of Al to Me of 1.20-1.50, a second layer, d, of hard and wear resistant refractory PVD AlMe nitride or carbonitride where Me is Zr, V, Nb, Cr or Ti, having a thickness of 0.5-4.5 µm, and an atomic fraction of Al to Me of 1.30-1.70, and in between the first layer (c) and the second layer (d), a 0.05-1.0 µm thick low-A1 layer, (e), the thickness being less than 0.95 times the thickness of thinnest of the first layer (c) and the second layer (d), of an AlMe nitride or carbonitride where Me is Zr, V, Nb, Cr or Ti and an atomic fraction of Al to Me of 0-0.3.