Grinding temperature during high-efficiency grinding Inconel 718 using porous CBN wheel with multilayer defined grain distribution

Abstract

Porous cubic boron nitride (CBN) wheel with multilayer defined grain distribution was developed based on pore-forming effect of alumina bubbles and sintering technology. High-efficiency grinding experiments were carried out on a typical nickel-based superalloy Inconel 718, and grinding temperatures within the contact arc were measured. A strategy to control the grinding burn by clapping flake graphite around the workpiece was proposed, which was verified could improve the cooling effect in contact zone and increase the specific material removal at least three times higher in deep grinding. Being an attribute to the faster heat moving speed and good thermal conductivity of metal bond and CBN grains, grinding temperature reached 790 °C in the contact arc but nonvisible burnout marks were found on ground surface at Q′w = 25 mm3/(mm·s). At a wheel speed of 80 m/s, force ratio remains around 6 and specific grinding energy decreased from 187 to 67 J/mm3 at elevated specific material removal from 3 to 25 mm3/(mm·s). Results show that the developed porous CBN wheels have a promising application in high-efficiency deep grinding nickel-based alloy.