Category: Steels
4 thoughts on “Steels”
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Toughness testing – Cru-Wear, Z-Wear, Upper vs Lower temper, Cryo vs No Cryo
Thanks to Paul Hart and James Covington for becoming Knife Steel Nerds Patreon supporters!
I recently completed some toughness tests on samples that were heat treated by knifemaker Warren Krywko. The steel was donated by Chuck Bybee of Alpha Knife Supply. The samples are subsize unnotched charpy specimens with dimensions as specified on the bottom of this page: http://knifesteelnerds.com/how-you-can-help/ If we can get more people to make toughness specimens we can have more comparisons between steels, hardness points, heat treatment parameters, etc. Patreon dollars are for the purpose of paying for machining, shipping, testing, etc. for tests like toughness and CATRA edge retention, so if you are able to contribute that way please visit the Knife Steel Nerds Patreon page.
154CM – Development, Properties, Use in Knives, and Legacy
Update 6/19/18: I have added new toughness numbers from a 1962 publication comparing 440C and 154CM. Go to the bottom of the article to see them. Thanks to Russ Andrews for sending me the article.
Thanks to Sal Glesser, Brian Huegel, Mark Bellou, Timothy A. Johnson, Daemon Lindenmayer, and David Olkovetsky for becoming Knife Steel Nerds Patreon supporters! We reached our goal of funding an edge retention study!
Why There is Cobalt in VG-10
Thanks to Phil Wilson for become a Knife Steel Nerds Patreon supporter. We have now reached our second goal of funding a toughness study! I will start putting together the plan and discussing it with the patrons. Next goal: funding an edge retention study.
Is Spider Silk Stronger than Steel?
This article was discussed on the very popular Skeptic’ s Guide to the Universe podcast: https://www.theskepticsguide.org/podcast/sgu/670
Nearly a year later they briefly discussed the article as being very impactful in correcting some common knowledge they had always believed: https://www.theskepticsguide.org/podcast/sgu/714
Reader Question – O1 vs 80CrV2
Larrin,
Someone said austempered o1 would be as tough or tougher then martempered 80crv2. Could you help me wrap my head around that?
I have an affinity for fine grained simple steels, and o1 being precision ground and available in all different sizes is great, but if 80crv2 has a finer grains structure and is tougher I’d be sold. It’s for a run of belt hawks that will be used primarily for woods and hunting duties not destruction tools. But I’d also like to focus on one steel for a while and curious if for small to medium belt knives which you’d recommend? I’ve played with most of the high wear and too steels, but haven’t messed with too many of the high carbon steels as I hated 1095.
The Development of High Vanadium Steels, M4, and the First Tool Steels Book
Thanks to Gary Cornell and Devin Thomas for becoming Knife Steel Nerds supporters on Patreon.
Last Time, in Steel History….
When we last left steel history, the first high speed steels had been developed which had led to an explosion in steel development. I covered all of this in The History of the First Tool Steel. A few highlights of that article:
Is Blue Super Steel Actually Super? The Facts about Tungsten-alloyed Steels
High carbon, tungsten-alloyed forging steels see consistent use in Japanese knives with steels like the Hitachi Blue series and Takefu V-Toku steels. These steels differentiate themselves from many other knife steels due to their use of tungsten alloying, but not for providing hot hardness like in high speed steels, but for wear resistance. Tungsten-alloyed steels are as old as tool steels themselves, as I covered in an earlier post: The First Tool Steel. However, simple tungsten-alloyed steels have been on their way out in the USA since at least the early 60’s [1]. The tungsten added to the steels leads to the formation of very hard tungsten carbides for steels that can be as wear resistant as air hardening steels like D2 or M2 but with the ability to normalize and anneal the steels without precise temperature control.
Cru Forge V – Toughness testing, Processing, and Background
Cru Forge V was developed by Crucible for those who forge their steel for knives [1]. It was developed shortly before Crucible’s bankruptcy and is reported to have been tested with the help of knifemakers Howard Clark and Dan Farr and that the code name prior to its official name was 1086V [2]. The steel is not listed anywhere on Crucible’s website and does not appear to be in production any longer, but as of March 2018 is still available from some third party steel sellers [3][4][5]. The steel has the following composition [1]:
Micrographs of Niolox, CPM-154, and AEB-L
Update: 1/6/2020: I have taken micrographs of many more steels which you can see here.
Recently I had samples of Niolox, CPM-154, and AEB-L analyzed with SEM. Vilella’s reagant was used which is common for tool steels and martensitic stainless steels because it etches the martensite matrix so it is dark and leaves the carbides bright. The compositions for the three steels:
3v Modified – The Lost Crucible Steel
I enjoy reading patents from steel companies, it reveals information about new products and research often not available otherwise. One thing I’m surprised there isn’t more talk about is a steel Crucible patented but never sold – an improved 3V: https://www.google.com/patents/US7615123
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.