Thanks to Lewis, David Abbot, and Nick Shabazz for becoming Knife Steel Nerds Patreon supporters!
5160
5160 is a low alloy steel known for its excellent toughness. It has been used by many forging bladesmiths due to its good properties and also wide availability, especially in the form of leaf springs. However, information on how to maximize the steel’s properties with heat treating is scant. So along with my father, Devin Thomas, we did a small study on the toughness of 5160.
Thanks to David Suitor, Drakopoulos Stelios, and Maxim Bellehumeur for becoming Knife Steel Nerds Patreon supporters!
Vanax
Vanax is an interesting steel because of its good combination of toughness, wear resistance, and corrosion resistance. I wrote about Vanax along with other nitrogen-alloyed steels in this article, to describe how the steel is designed. While the datasheet shows it being capable of 59-61 Rc, I was curious about how hard the steel can go. The steel may be good for kitchen knives, for example, where very thin edges and high hardness is common. And kitchen knife users may appreciate the excellent corrosion resistance of Vanax in the presence of water, salt, and acidic foods.
Thanks to Damion for becoming a Knife Steel Nerds Patreon supporter!
How a Magnet Helps in Heat Treating
It is somewhat common for knifemakers to heat treat low alloy steels in a forge or with a torch, two methods where tight temperature control is not possible, and the temperature is frequently not even known. A magnet is often used to check the temperature of the steel because the point at which the steel becomes nonmagnetic is near the temperature at which the steel should be quenched to achieve high hardness. How does steel magnetism work? How reliable is checking the steel with a magnet?
Thanks to Marco Guldimann, Darrin Thomas, Jason Tillostson, Dominic Paolantonio, Ken, Benedikt Peters, and Steve Greiner for becoming Knife Steel Nerds Patreon supporters!
Cold Forging
Cold forging is a lot like hot forging except it is at or near room temperature. The lower temperature means that the steel is much stronger and it is much more difficult to forge. That also means the steel is more brittle and therefore more likely to crack during forging or rolling. The shape of the grains in the steel are changed through forging. You can read about what grains are in this article. Steel is made up of planes of iron atoms, and if the steel was made up of only one grain these planes of atoms would all be parallel to each other:
Thanks to anteck7 and Aaron Lee for becoming Knife Steel Nerds Patreon supporters!
History of AEB-L and 13C26
Tracking down the history of AEB-L was surprisingly difficult. The Uddeholm website claims that AEB-L was patented in 1928 [1]; however, that is not entirely truthful. Uddeholm did patent a stainless steel in 1928 [2], which was named AEB, and later AEB-H to differentiate it from AEB-L. This was a very early stainless steel, so its development and patent needs to be viewed in that historical context. You can read about the development of stainless steels in this article. The AEB patent was for 0.7-1.1% carbon, 10-16% chromium, and 0.75-2.0% manganese. The original Brearley and Haynes stainless steel patents were still in effect; they got around them by using a higher carbon content than the Brearley patent (had a 0.7% max), and by claiming that high Mn led to improved corrosion resistance (it actually doesn’t). The nominal composition of AEB became 1% carbon and 13.5% chromium, which gave it a relatively large carbide structure compared to AEB-L, but it did see some use as a razor blade steel.
Thanks to Richard Patterson, Patrick Guignot, Aaron Lee, and David Richardson for becoming Knife Steel Nerds Patreon supporters!
Hardenability
How fast one must quench steel is controlled by its hardenability. Hardenability is not a measure of how hard a steel can get. Instead it is a measure of how fast you have to quench to achieve max hardness for a given composition. Therefore a steel with 0.2% carbon can have high hardenability without being able to reach a particularly high hardness; the steel can be allowed to cool in air and achieve more or less the same hardness as when it is quenched in water. On the other hand, a steel with very high carbon content that can reach very high hardness can have low hardenability, requiring a water quench to achieve its potential hardness.
Thanks to David Palacios for becoming a Knife Steel Nerds Patreon supporter!
Niobium-Alloyed Steels
Here is a partial list of some niobium-alloyed steels, and I will describe the reasons why the niobium addition was made:
Thanks to Fingal Ferguson for becoming a Knife Steel Nerds Patreon supporter!
CATRA Edge Retention Testing
I previously wrote articles about CATRA testing of edges. The CATRA test uses 5% silica-impregnated cardstock which it slices with a fixed stroke length and force. The first article primarily looked at the effect of edge angle on edge retention; specifically, that edge angle greatly controls edge retention:
Thanks to Jason Volkert for becoming a Knife Steel Nerds Patreon supporter!
Introduction
In July 2018 a new book was released on the research of wootz Damascus steel by Dr. John Verhoeven. Dr. Verhoeven is well known for his contributions to research on knife steels and damascus, along with frequent collaborator Al Pendray. Dr. Verhoeven has often been cited on this website, including his articles on CATRA testing of different knife steels [1], and also a series of experiments on sharpening of knives [2]. He also wrote a book on the metallurgy of knife steels, which is now published as Steel Metallurgy for the Non-Metallurgist; I reviewed it in this article on book recommendations. Dr. Verhoeven had a particularly strong impact on my interest in steel and metallurgy. I was introduced to him through his knife steel metallurgy book which I read several times in my teen years. And when I was looking for the best steel University to attend, he was the first person I emailed for advice. I asked him for an interview to be published on this website, and he asked if I would be willing to review his new book instead – Damascus Steel Swords: Solving the Mystery of How to Make Them.
Thanks to Phil Zhou for becoming a Knife Steel Nerds Patreon supporter! I’ve started posting early test results for things like heat treatment experiments, retained austenite measurements, etc. on Patreon. The data will eventually be posted to this website, but if you want to see it as it comes then get on Patreon.
