Category: Edge Retention
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Testing Chinese Knife Steel 8Cr13MoV/8Cr14MoV
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Thank you to my Patreon supporters who help make these studies happen. Patreon funds were used for purchasing two ultimately useless knives, and some steel. Patreon supporter Marcus Ho even sent me some steel all the way from China which also ended up not working out. And I used Patreon funds to pay Shawn Houston (also a Patreon supporter) to do microscopy and grind two CATRA knives for me. So when I say that Patreon makes the study happen I don’t mean in an abstract sense. If you want to help fund more knife steel research please come join us on Patreon where you can get articles and videos early. Or if you sign up for the highest tier you can even get a sweet Knife Steel Nerds mug.
Does Damascus Outperform Super Steels? Testing Different Combinations
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Vancron and the Problem with Nitrogen Knife Steels
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What is the Best Hardness for MagnaCut Knives?
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Knife Steels Rated by a Metallurgist – Toughness, Edge Retention, and Corrosion Resistance
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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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Vanadis 8 – Better than CPM-10V
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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.
CPM-S110V Steel – History and Properties
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How the hell does CT’s xhp hold an edge so long?
Way slow in the reply here, but it has a large carbide volume and can hold high hardness. So, it’s not going to end up that tough, but it will be strong.
I did a plane iron test (for woodworking) two years ago and found it to plane double the linear footage that O1 will at same hardness.
Then larrin posted his results confirming that was in line with catra testing (which was a relief – I got a lot of grief from the woodworking community). What I’ve found since then is that you have to have something relatively easy on the edge (so planing rough lumber will reduce its advantage over more plain steels).
But I’ve made a couple of mules out of XHP for the kitchen and it’s great for low toughness work (and where it won’t lay in salt and rust).
I’m just curious looking at the large steel comparisons, I don’t quite understand, I’ve been told that high carbon steel holds an edge very well but all the high carbon steels on your list seem to be very poor at edge retention. I am just a very uneducated person on this topic who just happened upon this looking for interesting comparisons between knife steels so if I’m missing something or glossing over something on accident I apologize I am just very confused honestly.
Low alloy and simple carbon steels have a small volume of low hardness carbide called cementite. That means the west resistance is much lower than high alloy steels that have more carbide and the carbide is higher in hardness. This is discussed in the CATRA articles and Knife Engineering.