With several of my coated Bussekin blades I have found that the edge is not actually ground in deep enough to reach the actual heat treated layer of steel with all of it's properties. If your edge is say .005" away from that level, a good resharpening can make a world of difference if it takes you into the properly treated layer. I don't know if there is a way to even see it at the point of sharpening at the factory since I can't see it when I sharpen, <img src="/ubbthreads/images/graemlins/confused.gif" alt="" /> but I do know the performance difference between the right depth of sharpening and not is night and day. The outer heat treat layer can be slightly brittle and easy to dull, more with SR101 than INFI, but INFI will dent/roll pretty easy in that layer. Just my personal experience with having used 30+ different Wauseon blades.
Good insight, but we should be careful as there is a lot of information that could be interpreted incorrectly from this.
I do not know the heat treat processes that Busse/kin use, but you would have to look at the crystalline grain structures to really get an understanding about what type, if any, variation is obtained in the process.
Brittle is typically associated with higher hardness values, which is not necessarily associated with dulling easily. Chipping out, yes, but this isn't really a concern when cleaning a deer (or other "cutting" type motions that do not involve "chopping"). Arguably, higher RC (within reason) is a desired feature for a slicer so that it will retain it's edge longer.
If anything, one might argue that while the knife is originally sharpened...the edge is slightly annealed due to over-heating, creating a larger grain size and a localized softening effect (reduced RC)...which would make it more difficult to hold an edge. This annealing process would effectively alter the heat treat locally. This may explain what you're seeing...and as you sharpen below it, keeping temperatures low enough...you are able to reach the properly heat treated sections of the blade.
I can't confirm this, however, as destructive testing would need to be done for verification. Your experience speaks for itself.
