Improved superalloy grinding performance with novel CBN crystals

The superior thermal properties of nickel-based superalloys that make them suitable for use in gas turbine blades and vanes also make them difficult to grind. Cubic Boron Nitride (CBN) crystals, which possess high thermal conductivity, lend themselves to superalloy grinding by dissipating the grinding heat more effectively than conventional abrasives. Even so, productivity is constrained by the propensity of superalloys to suffer thermal damage when using accelerated grinding parameters. Furthermore, the process economics hinge on maximizing grinding wheel re-profiling intervals and the overall wheel life. In this paper the performance of two novel CBN crystals in grinding Inconel 718 as function of the wheel life, the workpiece surface characteristics, and the process energy requirements is examined. The significantly improved performance of these new CBN crystals is compared with that from commercially available CBN. Possible mechanisms to explain the performance of the new crystals are discussed. (AU) © 2010 by The Materials, Metals, & Materials Society. All rights reserved.