Cemented carbide insert for toughness demanding short hole drilling operations

摘要

The present invention relates to a coated cutting insert with excellent toughness properties particularly useful for toughness demanding short hole drilling in low alloy and stainless steels and a method of making the same. The inserts comprise a substrate and a coating. The substrate comprises WC, from about 8 to about 11 wt-% Co and from about 0.2 to about 0.5 wt-% Cr with an average WC-grain size of from about 0.5 to about 1.5 μm and a CW-ratio of from about 0.80 to about 0.90. The coating comprises a laminar, multilayered structure of TiN+Ti_1-xAl_xN+TiN+Ti_1-xAl_xN+TiN . . . in polycrystalline, non-repetitive form, with x being from about 0.4 to about 0.6 with a thickness of the individual TiN—or Ti_1-xAl_xN-layers of from about 1 to about 30 nm varying essentially at random and with a total thickness of the multilayered coating of from about 1 to about 5 μm. The layers are deposited using arc evaporation technique.