Development Of CBN Wheels With Regularly Distributed Bubbles And High Speed Grinding Of Nickel Superalloy

At present, limited to the development level of corundum grinding wheels and CBN grindingwheels, low machining efficiency, short tool life, low quality consistency have been the mostremarkable problems during grinding nickel-based superalloy, which is the representative of difficult-to-cut materials. In view of this, metal-bonded cBN wheels with regularly distributed bubble particlesare developed for high speed grinding of nickel superalloy GH4169. That is, alumina (Al2O3) bubbleparticles as pore-forming agents and reinforcement particles are added into the bonding materials, i.e.Cu-Sn-Ti alloy. The abrasive layer is sintered depending on the chemical reaction among Al2O3, CBNand Cu-Sn-Ti alloy. Then, metal-bonded CBN wheels with regular pores are fabricated with highporosity and high strength. The result of this research could provide the tool support for high speedgrinding of difficult-to-cut materials.The main contents are as follows:(1) Based on finite element simulation and grinding experiments, the size of the alumina bubbleshas been optimized. The results show that, considering the grinding force, the grinding temperatureand the wear behavior of the wheels, cBN wheels have better grinding performance when the size ofthe pores is500~600μm. The abrasive layer with regularly distributed bubbles is fabricated using theoptimized distribution templates for the alumina bubbles.(2) The fracture morphology of the abrasive layer is observed using the modern analysisequipments. Results show that, depending on the chemical reaction among Al2O3, CBN and Cu-Sn-Tialloy, good joining interface is obtained. Moreover, high bonding strength between the abrasive layerand the wheel substrate is acquired using heat cured epoxy adhesive as the bonding material, whichmeets the requirement of the peripheral wheel speed of162m/s.(3) The grinding performance of metal-bonded CBN wheels with regularly distributed bubblesand vitrified CBN wheels is evaluated in the high speed grinding experiments of nickel superalloyGH4169. Compared to vitrified CBN wheels, metal-bonded CBN wheels with regularly distributedbubbles have the obvious advantage in terms of grinding force, grinding temperature and specificgrinding energy.