# S90v Core, Damascus Staninless



## bonesetter (Nov 11, 2015)

CPM S90V with (further) stainless Damascus clad?

What's that like to live with?

Seems a specialty, so very little feedback out there

A very quick look around says bitch to sharpen


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## phatch (Mar 29, 2002)

It is difficult to sharpen. Also has large carbides so expect to see some carbide "chips' and voids in the edge over time.

Also the initial sharpening is often problematic. The power tools used to put on the initial edge often overtemper the thin steel at the edge so you'll be doing some initial work to remove that if it happened in your sample blade. 

It's quite tough, and holds an edge a long time. It's best to not let steels like this dull much before maintenance. Much easier to maintain sharp than actually resharpen. 

Most here probably wouldn't like edge behavior. it's not a bad behavior, just different and a bit work intensive for kitchen use imho. 

m4, m390 are similar high performance steels and friendlier I think.


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## rick alan (Nov 15, 2012)

Look at Phil Wilson's comment near the bottom, he is THE expert on using PM metals in knives.

http://www.bladeforums.com/forums/showthread.php/970308-CPM-s90v-steel

S90V in fact has carbides finer than white steel, which is perhaps the finest grained of conventional steels. A problem with these super high wear resistant PM steels is the edge stability, which suffers due to the high carbide content. This means micro-chipping at very acute angles.

The way around this problem is to micro-bevel to 30deg inclusive, or even a little more. There is very little loss of performance there as the edge is still rather thin, and very keen due to the small carbides.

I've never tried sharpening this steel myself but what I understand about S90V, S110V and similar alloys is that for best results you need diamond loaded strops. Phil Wilson finishes with a fused ceramic stone sold by Spyderco, which he feels an improvement over conventional waterstones here.

Perhaps conventional waterstones leave a rough edge on S90Vand this makes people think it has course carbides. Don't know, other PM steels like SRS-15, HAP40 and M390 don't seem to have these problems, and I believe they actually have courser carbides compared to S90V. Not sure what leads folks to think otherwise about S90V.

I think eventually we will see PM steels that will have the fine grain structure, great wear resistance, and much better edge stability also.

Rick


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