Sharpening D2 steel

[yuzuha]

Vassili - I'm not saying that D2's hard to sharpen, just that results depend on the medium used. And we do seem to agree that diamond is the best way to go.

However you can't realistically compare the vanadium content of D2 the way you have to that of CPM steels which are engineered to permit higher vanadium content without the associated problems in non-CPM steels. Here's a brief reference from Crucible:

http://www.crucibleservice.com/products/CPM/toolSteel/index.cfm

D2 is known for its tendency towards segregation of carbides. While it's true that D2's wear resistance is largely due to the chromium carbides, vanadium levels in D2 are higher than the .15%-.20% needed for grain refinement and hardenability. So much of that .9%-1.1% vanadium in D2 is available for carbide formation -- and again, because it's not a CPM, and due to overall makeup of the alloy, these carbides have the potential to be fairly large.

Don't think it is the vanadium. I think it just forms larger than average carbide particles that tear out easily if the edge is too thin so it just never seems to get sharp or seems to sharpen to a saw tooth (hence the addage "D2 takes a lousy edge and holds it forever"). I have no trouble getting a smooth polished edge on it with ordinary waterstones as long as I keep the angle at around 17 degrees per side (whittling knife so I like a slightly stronger edge than 15 per side gives)

 

[nozh2002]

Don't think it is the vanadium. I think it just forms larger than average carbide particles that tear out easily if the edge is too thin so it just never seems to get sharp or seems to sharpen to a saw tooth (hence the addage "D2 takes a lousy edge and holds it forever"). I have no trouble getting a smooth polished edge on it with ordinary waterstones as long as I keep the angle at around 17 degrees per side (whittling knife so I like a slightly stronger edge than 15 per side gives)

I think carbide also get sharpened - iron carbides are softer then usual abrasive and so this 50-80 micron carbides got sharpened as well as surrounding iron. I can get it whittle sharp and if tose carbides did not get shaped I doubt that it will e possible. And I am not sure that they tear away easy.

Thanks, Vassili.