K390

K390 is a steel made by Böhler Uddeholm and consists of:

Carbon

Chromium

Cobalt

Copper

Manganese

Molybdenium

Nickel

Nitrogen

Phosphorus

Silicon

Sulfur

Tungsten

Vanadium

2.47

4.20

2.00

/

0.40

3.80

/

/

/

0.55

/

1.00

9.00

Information from the Spyderco catalog on the web

K390 steel is produced by the Böhler Uddeholm steel company, headquartered in Vienna, Austria. K390 is a powdered metallurgy, cold work tool steel with 9% vanadium and added tungsten and cobalt for excellent wear resistance and high compressive strength that is a workhorse in even the most severe applications. The carbides in the K390 mix are fine in textured and the steel’s remaining components are uniformly sized and distributed evenly throughout the matrix. This equal distribution of elements adds to the overall strength and cutting capacity when the blade is finished and sharpened.

History, mentionings from the forums etc.

In this post on the Spyderco.com forum, from 31 May 2021, Sal Glesser shares the k390's history with Spyderco:

K390 was "my baby" from the beginning. While I'm not a metallurgist, I do have some understanding of blade steels and the chemistry of K390 caught my attention. First I made a Mule Team, which was well received. (two years on the making). Then it took another year plus to get our Japanese partner to learn to work with it, (not easy) and then we moved to make the entire Endura family in the steel. It is not stainless, which even I have managed to get some pitting ( my bad) but it has some high performance edge strength that is surprising. We are pleased to be able to offer this steel to the knife afi's that enjoy it.

And yes, I'd like to see a Shaman in this steel, even with an FRN scale (to keep the cost down).