Traditional charcoal & bone case color

[Craig Budgeon]

Edgar. you can not do a Rockwell test or a Brinnell test on a casehardened surface because the depth of the case is in the case of a gun receiver is less than .002 deep. Therefore when the diamond penetrator enters the casehardened surface it enters to deep giving a false reading. Casehardening leaves the inside soft which makes the component stronger. Carbon steels have a carbon content of 0.4% or higher and will harden through the entire part although the core will be softer than the surface