History - Articles - Books, Super Steels

Testing Super High Speed Steel Vanadis 60

The following is a collaboration project between myself and Malachi Chou-Green. He obtained the Vanadis 60, did some heat treating experiments, and also did metallography including some fancy electron microscopy. He also heat treated and machined the CATRA knife that I tested. His original experiments were published some time ago on his Patreon, so if you want to see what he is up to I recommend visiting his Patreon page and becoming a supporter. read more

History - Articles - Books, Steel and Knife Properties, Super Steels

K390 – Best High Wear Resistance Steel?

Thanks to the new Knife Steel Nerds Patreon supporters! Dusan Praznik, Donald Adkins, Marcus Collins, and Trae Santiago.

K390 Video

Here is the video version of the following information:

What is K390?

K390 was developed as an alternative to Crucible’s CPM-10V, which has had success since the late 1970s as a steel with very high wear resistance yet also moderate toughness. CPM-10V achieved these properties by having a relatively high volume of vanadium carbides, very hard carbides that contribute greatly to wear resistance. Because the carbides are so hard, it requires less of them for a certain level of wear resistance. Carbides are brittle, so having a lower volume of carbide for the same wear resistance means greater toughness. The patent application for K390 was submitted in Austria by Bohler in 2002 [1], and the steel was announced in 2004 [2]. The main modifications to CPM-10V were increased Mo, W, and Co. This gives K390 better “secondary hardening” and therefore “hot hardness” so that it can maintain its hardness at high temperatures. The higher Mo also gives it greater “hardenability” so that large dies can still harden all the way through. read more

Edge Retention, History - Articles - Books, Super Steels

CPM-15V and the Lost CPM-20V – How Much Vanadium Can you Add?

Thanks to Tim Marais, Daniel DeRosia, Jess Hoffman, David Rogers, Mo, John Macklis, and R. Thomas Buffenbarger for becoming Knife Steel Nerds Patreon supporters!

History of CPM-15V

CPM-15V is essentially a higher vanadium extension of CPM-10V developed by Crucible steel in the late 1970s. I wrote about the history of CPM-10V in this article so I won’t copy-paste all of that here. Prior to powder metallurgy technology it was known that adding higher vanadium would lead to greater wear resistance due to the very high hardness of vanadium carbide. However, once the vanadium content exceeded 4-5% the carbides would be large enough that the steel would fail in forging, and toughness would also be reduced. So the highest wear resistance steel for many years was T15 high speed steel with ~5% vanadium. With CPM-10V they saw what the limit was for vanadium additions and found that once they reached about 11% vanadium the carbide size would be increased because the vanadium carbides would form in the liquid steel before the steel could be gas atomized into powder. Read about the powder metallurgy process in this article. The more vanadium that is added the higher the temperature where the vanadium carbides form. When the formation temperature is higher than the temperature of the liquid steel then they form prior to atomization giving the large carbides in the 11% vanadium PM steel below (labeled CPM 11V): read more

Edge Retention, Super Steels

Edge Retention Testing of Seven More Steels – XHP, SPY27, Maxamet, Rex 45, 420, T15, Rex 76

Thanks to Knife Thoughts, Nicholas Rossi, Jason D. Stone, and Ken McCurdy for becoming Knife Steel Nerds Patreon supporters!

Update 1/5/2024: I neglected to mention in the original writeup of this article that the Z-Max was retested along with the new Maxamet and Rex 121 tests. The total cardstock cut was updated from 909 in the original testing to 948 mm. read more

Edge Retention, History - Articles - Books, Super Steels, Toughness

Vanadis 8 – Better than CPM-10V

Thanks to Will and Justin Mann for becoming Knife Steel Nerds Patreon supporters!

My book Knife Engineering is available for Christmas and Hanukkah presents.

History of Vanadis 8

The history of Vanadis 8 goes back a lot further than just the steel itself, really we have to know the history of 10V to know all of the background that is relevant. You can read about CPM-10V in this article. CPM-10V is important because Vanadis 8 is intended as a replacement for CPM-10V, or at least for similar applications. CPM-10V was developed by Crucible in the late 70s, as the first powder metallurgy steel to utilize a microstructure made up of only vanadium carbide, as opposed to chromium and molybdenum/tungsten carbides. This gave 10V a combination of good toughness along with very high wear resistance from the ~10% vanadium and therefore ~17% vanadium carbide. read more