Category: Super Steels
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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.
What is Next After MagnaCut? Q&A Video
New YouTube video is a Q&A from Knife Steel Nerds Patreon supporters. The following topics were covered:
Nitro-V vs 14C28N
Carbide pullout during sharpening
What is difficult about high hardness heat treating of MagnaCut
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.
What is M390MK Knife Steel?
Thanks to the new Knife Steel Nerds Patreon supporters! Clive Russ, Anthony Rhodes, Travis, Coulter Moulton, Chas Newport, Kevin Fonseca, Tyson Wright, Ryan Davis, Richard Patterson, Joseph Baier, Adam Smith, Wade Chappell, Brian, Julian Hamilton, Mikhail Popov, and Clarence Hanselman.
How to Heat Treat ApexUltra Knife Steel
Thanks to Windscion, Kalib Maxwell, Jan Ysselstein, Klaas Alberts, Zoltan Gero, Mark Nielsen, Christian Lishen, and Richard Smallwood for becoming Knife Steel Nerds Patreon supporters!
What is ApexUltra?
Laboratory Development of ApexUltra Forging Knife Steel
Note: I have a new article on ApexUltra that shows properties of the final product (as opposed to these experiments with “lab scale” production). And also heat treatment recommendations on the final steel. Click here to read the newer article.
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):
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.
CPM MagnaCut – The Next Breakthrough in Knife Steel
Thanks to Saptak Dutta, Bill Clancy, Cap Hayes, Electro_Static, Coll Gomila, Kody Ekstrom, Nico, Tom Ewing, Ken Johnson, Brent Stark, Jesse Warren, Malachi Chou-Green, Luke Haag, Bill Harrison, John Geelhoed, and Julian Hamilton for becoming Knife Steel Nerds Patreon supporters!
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.
Hello i kinda stumbled across your site looking for. Spyderco zdp189 metal information as I’m looking to swap to a custom set of replacement blades for my titanium scaled Byrd 8cr. 3pcs set.
A simple blade swap would be nice but, they don’t have any replacement options so started to look at making a set my self from Vg10 or S35v but have no idea if need pre heat treated steels or to cut grind the blades first then heat treat…? I’m a small hobbies guy and have had to get creative with this project, because I’m stubborn, there isn’t getting parts like most spyderco knives which annoyed me greatly so i now made it harder by trying to make custom blades and parts to retrofit.
I’m completely new to this and was just trying to make a small upgraded twist but i got dragged down a rabbit hole trying to get help. And i spoke to spyderco an they dont have plans to update the steels in the byrd line.
When you buy steel it is annealed soft for working. You have to cut and drill the blade before heat treating, though some people partially grind the bevels before heat treatment as well.
I’ve looked through your website and to say the least I’ve learned a lot about steel that I didn’t know and otherwise likely wouldn’t!
Out of curiosity what steel would you recommend that has high wear resistance and good if not really good tuffness?
Depends on how much wear resistance you need. In my recent article on Vanadis 8 I was impressed by how much of a toughness improvement it had over CPM-10V.
hi
im curious about relation between hrc and rex-121
if hrc of rex-121is below 70 edge retension will be significantly lower than over 70 hrc?
Hi I’ve been doing a lot of browsing around popular sites that sell custom knives, and comparing them to my own knives that I’ve made with a variety of high grade high carbon stainless steels, and high speed steels. Many companies claim to use the most high quality high carbon steels rather than stainless steels, and according to your knife steel ratings, there are numerous stainless steels that have a higher balance of hardness and toughness as well as corrosion resistance. If these knives they sell are home forged, I have a feeling they would be made with a carbon steel that is more forgiving when it comes to heat treatment which don’t compare to most super steels.
I read your article on vg10 and super gold steel which are very common in Japanese knives; but looking at some other high alloy stainless steels such as s35vn and s45vn, they are said to be even better. However I don’t find many people that make knives with s35vn other than fold knives. Do very many people understand the difference in quality when it comes to metallurgy?
There are a lot of factors that go into steel choice including availability. It is relatively difficult to obtain VG10 and Super Gold in the USA but easy in Japan. I’ve never tried to buy CPM steels in Japan but I imagine buying the domestic steels is easier and potentially cheaper.