It is wise to visually inspect incoming bearing components for damage, especially on the raceways. Damage at this point will lead to “NCU,” or “no clean up,” at grind and a complaint from your customer. Many bearing components are distortion-prone. A sample-size measurement of key attributes (or actual turning dimensional data) is also advised to establish that the turning supplier did their job correctly.
If the components are carbonitrided or carburized, carefully wash them to remove oils and washing fluids to ensure uniform carburizing. I cannot overstate the importance of a clean surface to interact with the carburizing atmosphere to prevent wavy case. Cutting fluids, hydraulic oil leaks and residual washing fluids can all impact results of carburizing.
There are a few carburizing material grades, especially those with high alloy or high silicon (like CBS600, M50-Nil or CBS1000), that require a pre-carburizing oxidation step to prepare the surface for effective carburizing. These materials are typically used in higher-temperature applications or for aerospace bearings.