Don,
My non-statistical sample of cutting into a couple pieces of case hardened steel leads me to believe that while there is a uniformly hard layer of something like .002-008", there is also a gradient of hardness many times that. I base this on the machining of the steel and the observation of the finish. You can literally see the hardness gradient in terms of shineyness. I estimate that I've seen layers of gradient hardness up to .050". Or at least the gradients of shineyness up to that.

Last edited by Chuck H; 06/06/12 11:27 PM.