Sintered diamond cutting tools - producing smooth surface finish and long tool life, esp. in turning non-ferrous alloys

摘要

The compact contains by vol. 20-95%, esp. 30-70% diamond powder with particle size 1 mu m, the remainder being a carbide binder, viz WC or (MoW)C, also with size 1 mu m and pref. cemented. The carbide may also contain 50 vol.% TaC, ZrC, HfC, TiC or NbC. The diamond powder is pref. obtd. by milling in a carbide mill with carbide balls, where the carbide is WC or (MoW)C; and a powder(a) is added to the mill to cause abrasion of the carbide lining and the balls, thus providing a powder mixed with the diamond; a carbide powder may also be added to the mill prior to milling. The powder mixt. is then degassed in vacuo at 300 degrees C., and hot pressed to mfr. the compact. The powder mixt. may be cold compacted before vacuum degassing. Used to obtain a cutting tool with increased working life, providing a very smooth surface finish on workpieces, e.g. Cu alloys or Al-Si alloys.