Category: Steels
4 thoughts on “Steels”
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How to Heat Treat ApexUltra Knife Steel
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What is ApexUltra?
Why Nitrogen Knife Steels are Soft
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I also have some Patreon-exclusive bonus content related to this article such as Nitrobe 77, Nitro-V, and 14C28N steel hardness data and experiments on the effects of the high temperature temper on nitrogen steel hardness.
Vancron and the Problem with Nitrogen Knife Steels
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H2 Steel – H1 the sequel
Background
A recent Spyderco Byte has announced a replacement for H1 steel – H2. H1 is known for being a very high corrosion resistance steel used primarily in Spyderco’s Salt line of knives. I have a previous article about the design of H1 and how it “works” which you can read here. I am somewhat tempted to re-write large chunks of that article here because H1 is one of the most misunderstood knife steels but I am going to try to hit a few of the highlights without much explanation and I hope you will read the earlier article to understand what I am referring to:
Wood Knife that is 3x Sharper than Steel? Spoiler: No
Several people have sent me links to a recent publication about a process that increased the hardness/strength of basswood. They then demonstrated the success of their processing by making a knife and a nail out of the wood. See here for an example of one of these articles: https://www.cnet.com/news/scientists-create-a-wooden-knife-thats-three-times-sharper-than-steel/
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.
LC200N/Cronidur 30 – History and Properties
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New T-Shirts!
After requests from any kind fans we now have t-shirts available, including an awesome one with the MagnaCut logo on front and knife grinding man on the back. Note it is available in a few different styles and colors. Click this link if you want one.
CPM-15V and the Lost CPM-20V – How Much Vanadium Can you Add?
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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
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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
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Thanks for what you are doing. There is so much misinformation, hyperbole, and exaggeration being presented as fact on the internet regarding knife blade steel. I felt like the skies cleared when I discovered your site. I really appreciate your science-based approach to demystify so many issues.
Thanks!
Can you tell me about AR-RPM9 please?
Thanks,
Mine S
I’ve only written about AR-RPM9 in an article exclusive to the Knife Steel Nerds Patreon.