john hamilton wrote:
>
> I can understand one type of steel being harder than another. and so keeping
> an edge longer. But i don't understand why carbon steel can be made sharper
> (keener); since any steel can be reduced down to a couple of atoms on its'
> edge, so thus would be equally sharp, wouldn't you say?

Steel and iron is made of crystals. Different alloys and different heat
treatments lead to different crystal sizes. The steel does not reduce
the edge to layers of atoms but to layers of small crystals. Nearing
the atomic level all blades are serrated because of the crystal
projections. I don't know which type has what size cyrstals but I
suspect that's why the softer carbon steel can take a sharper but
shorter lived edge than the hardest steel.