Cubic Boron Nitride (cBN) composites play an important role within metals and hardened alloys machining field, usually removing grinding from production processes. The effectiveness of cNB composites depends, in general, on insert toughness studies. Cubic boron nitride compacts are produced by sintering under high pressure high temperature (HPHT) conditions, up to 8 GPa and 2000°C. At non-hydrostatic parameters, internal stresses have significant values, decreasing tool life. In this study, the addicional thermal treatment (in vaccum, under temperatures up to 1000ºC for 1 hour) is proposed as a way for increasing toughness and tool efficiency. The parameters used for sintering were 7.7 GPa and 1600ºC, with samples composition of 65%w of cBN and 35%w of binder. Wear level was determined during machining of an AISI 4140 steel hardened to 56-58HRc. Comparing machining results of obtained samples and Elbor® composite, it could be noticed that the addicional thermal treatment improved cBN inserts machining capability in 40%.
Cubic boron nitride; sintering; wear; thermal treatment
