D2 finish problem

[SteelSlaver]

I met up with another local maker and he showed me a very nice custom hunter he was getting ready to ship out. Very nice mirror like finish. When I mentioned I had problems getting that fine of finish with D2 he said maybe carbides where pulling out and giving me the little scratches I could never get rid of. I know D2 is very wear resistant and tough to sand, but, I have worn out a lot of sand paper on D2. I like the fine webbing that shows when it is polished, but, getting it scratchless seems impossible. Clean everything between grit changes etc. I have pretty much gone to a 600 grit pre HT and then 600 after with some time on a cork belt with rouge for my practical hunters. Just can't get a good mirror finish with the D2 and way to much hand sanding for what I charge for them. I do like the way it holds its edge. The carbide pulling out and scratching the finish seem reasonable. Opinions please.

Probably going to go with something on the order of CPM154 for my high polish grade anyway.

 

[sunshadow]

if this link works for you look at micrograph figure 5-7, which shows the carbide structure of D2 and compare it to the 52100 slide next to it.
http://books.google.com/books?id=ScphevR_eP8C&pg=PA72&lpg=PA72&dq=D2+carbide+size&source=bl&ots=P7C0WSux3G&sig=AENiIWj6Lii7S3GWZhdvrb2CL88&hl=en&sa=X&ei=dat7UePmCtLH4AOV34DADg&ved=0CFAQ6AEwAw#v=onepage&q=D2%20carbide%20size&f=false
large blocky carbides have a tendency towards fracturing and pulling out of the matrix and once they do that the carbides pollute the buffing pad and scratch the softer parts of the surface. Some of the superalloys I used to work with had the same issues in their pre homogenized states which made polishing them for metallographic examination frustrating. I chose CPM154 as my stainless of choice largely based on Roman Landis' charts of relative particle sizes

-Page

 

[SteelSlaver]

Thanks, link worked fine. I had never thought of that as a cause of the problem. Not going to waste no more time trying to super polish D2.

 

[james terrio]

Not going to waste no more time trying to super polish D2.

It's much easier to get a good finish on CPM-D2. But for what it costs, there are better alloys out there anyway. Satin or tumbled finish on regular D2 and CPM-154 for the polished stuff will serve you very well.