It's a layer of decarb that wasn't fully removed after HT I think. Been working bit by bit getting my CGFBM refinished and it's easy to tell the difference between the "real" infi and the layer of decarb. The layer is really really thin, but incredibly difficult to remove. I really wish I had a sandblaster to do the work for me, since a scotchbrite wheel in a drill is really slow going, and doesn't get into the corrugations.
And then a reply from Jerry...
Quote
The comp blades still have a layer of de-carb on them from the heat treat process. . . .That's the black or darker colored steel that you see above the edge. . . De-carb is very prone to rusting on pretty much any steel. . . If you remove it by either grinding or double cutting, then you have the real INFI steel surface and not the modified surface of the de-carb.
INFI has similar rust resistance to ATS-34 and D-2 due to the carbon to chromium ratio. . .
Make sense? If not. . . then you need to drink more!!!!!
