Patent ID: 6250855
Filing Date: 2001-06-26
Classification: B22F,C22C,C23C,Y10T

Abstract:
A coated cemented carbide cutting tool for wet or dry machining of stainless steels of different composition and microstructure, and of low and medium alloyed non-stainless steels, comprising:a WC-Co based cemented carbide body which comprises a WC+Co composition in the range of 10-12 wt % Co, 0.3-0.6 wt % Cr, an average WC grain size in the range of 1.0-1.6 .mu.m and a low W-alloyed binder phase with a CW-ratio in the range of 0.87-0.96; anda hard and wear resistant coating having a thickness of 1 to 8 .mu.m on said body that comprisesa first innermost thin layer of TiNa second layer comprising a multilayered structure of 0.05-0.2 .mu.m thick sublayers of the composition (Ti.sub.x Al.sub.1-x)N in which x varies repeatedly between the two ranges 0.45<x<0.55 and 0.70<x<0.80, the first sublayer of (Ti.sub.x Al.sub.1-x)N adjacent to the first TiN layer having an x-value in the range 0.45<x<0.55, the second sublayer of (Ti.sub.x Al.sub.1-x)N having an x-value in the range 0.70<x<0.80 and the third sublayer having x in the range 0.45<x<0.55 and so forth repeated until 12 to 25 sublayers are being built up,a third 0.1-0.5 .mu.m thick layer of (Ti.sub.x Al.sub.1-x)N, where x is found in the range 0.45<x<0.55a fourth outermost thin layer of TiNwhere the thickness of the second layer constitutes 75-95% of the total coating thickness.