03-14-2018, 05:07 PM
Thank you Jan. I think we've got it now. If the grains have a larger diameter (dimension) than the thickness of the material holding them in place then the structure, as a whole, would be weaker. Along these same lines we have satisfied our curiosity to some degree with regard to carbides present in the steel. While apex widths of sharpened knife edges are easily sub-micron, the carbides that may be present in the steel could be from 2 - 50 microns in diameter. It appears that different steels have different types and sizes of carbide content. We're on thin ice here research wise because our sources for this information are less than ironclad. Perhaps someone who has better knowledge and metallurgical resources than we have could shed a brighter light on this carbide size thing.
Our information indicates that a vanadium carbide has a Mohs value of 9.5. That's harder than most of the abrasives we use to grind a knife edge. No small wonder then that folks complain about sharpening these carbide laden steels. This and the mental image we now have of a 5 micron vanadium carbide particle perched within or atop a .5 micron thick piece of steel.
Our information indicates that a vanadium carbide has a Mohs value of 9.5. That's harder than most of the abrasives we use to grind a knife edge. No small wonder then that folks complain about sharpening these carbide laden steels. This and the mental image we now have of a 5 micron vanadium carbide particle perched within or atop a .5 micron thick piece of steel.