Category: Steels

4 thoughts on “Steels”

  1. 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.

    Reply

Leave a Reply

Your email address will not be published. Required fields are marked *

Corrosion Resistance, History - Articles - Books, Steels

Steel History – The First Stainless Steel was for Knives

Larrin

Update 7/23/2018: I added a small piece of new information on the development of 440C steel to the article. 

Thanks to Greg Hanson for becoming a Knife Steel Nerds Patreon supporter!

The writing of this article was made much easier due to the existence of The History of Stainless Steel by Harold Cobb [1]. If you want more information on the history of stainless and the people who developed it, check out the book. read more

Corrosion Resistance, Metallurgy Principles, Steels

How Much More Chromium Does D2 Need to be Stainless?

Larrin

Thanks to Devon Craun for becoming a Knife Steel Nerds Patreon supporter! Your support is funding knife steel research. 

Some materials like aluminum form a passive oxide layer that prevents further corrosion. Steel is not one of those materials. Instead, steel forms iron oxide, or rust, that doesn’t protect the underlying iron and flakes off leading to further corrosion. However, when sufficient chromium is added then a chromium oxide passive layer forms which protects the steel from corrosion in a similar way to a metal like aluminum with its own aluminum oxide layer. A simple schematic diagram shows the passive film vs rust [1]: read more

Heat Treating and Processing, Steels, Tempering, Toughness

Toughness testing – Cru-Wear, Z-Wear, Upper vs Lower temper, Cryo vs No Cryo

Larrin

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.  read more

History - Articles - Books, Steels

154CM – Development, Properties, Use in Knives, and Legacy

Larrin

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! read more

Steels

Reader Question – O1 vs 80CrV2

Larrin

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. read more

History - Articles - Books, Steels

The Development of High Vanadium Steels, M4, and the First Tool Steels Book

Larrin

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: read more

Steels

Is Blue Super Steel Actually Super? The Facts about Tungsten-alloyed Steels

Larrin

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. read more

Annealing, Austenitizing, Forging, Heat Treating and Processing, Steel and Knife Properties, Steels, Tempering, Toughness

Cru Forge V – Toughness testing, Processing, and Background

Larrin

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]: read more