N690Co as it is sometimes called, a Cobalt-enriched stainless steel from Austrian steel company Bohler.
Additions of chromium and vanadium enhance edge holding capability, while cobalt and carbon help to retain high hardness. Hardens and tempers to 57-62 HRC .N690 shares some similarities with it's other Cobalt-steel bretheren such as ATS-55 and VG-10, which are used by Spyderco. My N690 knives are tempered to 59-60 Hrc for maximum toughness and to avoid chipping and cracking of steel.
Here is a little stress test video
A custom order for my customer from U.K
Your knife is one of the most important tools you carry when camping, climbing, hunting or hiking. Dull blades are useless in a pinch. Carbon steel knives, like other iron and steel items, need to be cleaned and oiled to prevent oxidation damage.
Maintain Carbon Steel Knife
Rub the blade of your carbon steel knife with a metal-cleaning wadding, nonabrasive compound for metal polish. Let the knife sit until the oily liquid from the wadding dries white.