Spyderco Mule Hitachi Aogami Super Blue and Takefu Cobalt Special (COS3) super-steels

[nozh2002]

Just finished testing those two steels. Both turn out to be premium performers.

Aogami slightly better then COS-3, however COS-3 is stainless (I may say I guess it is VG-10 on steroids). I am not sure why it is only Cobalt Special, because it also has good amount of Moli and some Tungsten and Vanadium.

Both steel performs at ZDP-189/CTS-XHP/D2 Dozier level. Both are super performers. Aogami I put on 4th place and COS-3 on 6th.

http://playground.sun.com/~vasya/Manila-Rope-Results.html

Aogami:
C=1.3 Mn=0.2 Cr=0.2-0.5% W=1-1.5%
COS-3:
С=0.95-1.15 Cr=15-17 Co=2-3 Mg=0.3-0.5 Mo=1-2 Ni=0.25 Si=0.6-0.7 W=0.2-0.3 V=0.2-0.3

Results:
Cuts AOG COS-3 (in oz.)
000 - 0.5 0.5
001 - 1.0 1.5
010 - 3.0 2.5
050 - 3.5 4.0
100 - 4.0 4.5
200 - 4.5 5.0

It is really nice to see real super-steel from Takefu.
It is also nice to see Mule project bringing to our attention new super performing steels (COS-3 in particulat, Aogami is well known good old Hitachi steel).

Thanks, Vassili.

P.S.
Turns out that COS-3 was introduced about year ago by Fallkniven. Hope it will replace SGPS, Also it is listed as 62HRC on Fallkniven site.

 

[The Mastiff]

The Hitachi blue steel is the super blue steel. You have the composition wrong.

C=1.40-1.50
W= 2.00-2.50
V=.50

The cobalt special doesn't have enough Tungsten and vanadium to make any real amount of carbides leading me to believe that while sharpening easy, it won't hold up to the really hard cutting jobs which your testing doesn't measure. Falkniven IIRC has SPGS as their premium steel, with CoS next, then VG10 as their base steel.