| 摘要 |
A cutting tool insert for wet or dry machining of low and medium alloyed steels and stainless steels with raw surfaces comprises a cemented carbide body consisting of WC with an average grain size of 1.5-2.5 ~mm, preferably 1.7 ~mm, 10.9-13 (11-12) weight % Co and 0.2-1.8 weight % TaC + NbC, and a low W-alloyed binder phase with a CW-ratio of 0.87-0.99, and a coating. (CW-ratio = Ms/(wt.% Co /* 0.0161), where Ms is the measured saturation magnetisation of the cemented carbide body in kA/m and wt% Co is the weight percentage of Co in the cemented carbide). The coating consists of: a first (innermost) layer 0.1-1.5 ~mm thick of TiCxNyO2 (x+y+z=1), y>x, z0.2) with equiaxed grains 0.5 ~mm; a 2nd layer of 1-8 ~mm thick TiCxNyO2 (x+y+z=1, z = preferably 0, x>0.3, y>0.3) with columnar grains 5 ~mm; a 3rd layer of smooth, fine-grained (0.5-2 ~mm) k-Al2O3 0.5-5 ~mm thick; and an outermost layer of TiCxNyO2, preferably TiN, 1 ~mm thick. Also claimed is the production of the insert where the innermost layer is formed by known CVD methods, the 2nd layer is formed by MTCVD using acetonitrile as C and N source at 850-900 deg C, and where the k-Al2O3 is formed by known CVD methods. The cemented carbide has the composition 11.1-11.7 weight % Co and 0.5-1.7 weight % TaC+NbC, and a CW ratio of 0.9-0.95. The outermost TiCxNyO2 layer and k-Al2O3 layer is removed from along the cutting edge. |
