Austenitic Stainless, Corrosion Resistance, History - Articles - Books, Steel and Knife Properties

H1 Steel – How it Works

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Austenitic Stainless Steels

At its most basic, H1 is an austenitic stainless steel. Austenitic stainless steels are about as old as stainless steel itself, being developed by German metallurgists in the approximate time period of 1909-1912. They worked on 18% Cr, 8% Ni steels which are quite similar to common austenitic stainless steels like 301, 302, and 304. read more

Austenitizing, Edge Retention, History - Articles - Books, Steels, Tempering, Toughness

A2 Steel – History and Properties

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History

A2 steel is quite old, though determining the exact year it was released is a bit difficult. A2 steel was developed in the early 20th century during the explosion of tool steels that occurred after the discovery of high speed steel which was first presented in 1900. You can read about that history in this article: The History of the First Tool Steel. During the development of the first high speed steel included the switch from manganese to chromium as the primary hardenability element, and most high speed steels had about 4% Cr. That high chromium content was primarily for “hardenability” which is the degree of cooling required to achieve full hardness. A “water quenching” steel has low hardenability and must be quenched very rapidly from high temperature, and an “air hardening” steel can be left in air and it will fully harden. You can read more about hardenability in this article on quenching. The first high speed steel came to be known as T1, which had 4% Cr and 18% W (tungsten). The earliest record I have found of a precursor A2-type steel is in a summary of tool steels in 1925 [1], while summaries of tool steels from 1910 [2] and 1915 [3] do not have any similar steels. Therefore these types of steels probably arose sometime between 1915 and 1925. read more

History - Articles - Books, Steel and Knife Properties, Steels

All About AEB-L

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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. read more

Reviews

Book Review – Damascus Steel Swords: Solving the Mystery of How to Make Them

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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. read more

History - Articles - Books

Knife Steel Nerds 2018 in Review

Here at the beginning of 2019 I decided to write up a retrospective of Knife Steel Nerds so far. A lot of things happened in 2018. First of all, the Knife Steel Nerds website was started, with the first article being posted February 27, 2018. That first article was about a modified 3V steel developed and patented by Crucible but never sold as far as I know. Links to the website were not shared with anyone until March 8th, however. read more

History - Articles - Books, Powder Metallurgy, Steel and Knife Properties

All About D2 Steel – Development, Use in Knives, and Properties

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Update 10/22/2020: I now have an article with how to heat treat D2, PSF27, and CPM-D2 and it also includes toughness testing of each steel and edge retention testing of D2. https://knifesteelnerds.com/2020/08/31/how-to-heat-treat-d2-psf27-and-cpm-d2/ read more

History - Articles - Books

How I Became a Knife Steel Metallurgist

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When I was 16 I went with my father to the Las Vegas Custom Knife show. My interest in custom knives up to that point had been pretty limited. My father, Devin, has run a Damascus steel business for as far back as my memory goes. I remember looking at the A.G. Russell catalog and seeing some of the cool knives. I remember wanting a pocket knife, but I don’t remember being any more interested in knives than I was in, say, Vans shoes. At the knife show, however, my perspective changed. There was table after table of custom knives and custom knifemakers all with different styles and stories to sell their knives. Knifemakers come in all different types from the aw-shucks cowboy to the intense self-defense salesmen. I was most interested in the knifemakers that were making claims about the superior performance of their knives. From the lockup, to edge geometry, to steel, etc. there were barkers promoting it all. I spoke to a man who claimed that he had a proprietary steel for his fillet knives that was better than any other available. He flexed the knives 90° to demonstrate the superiority of the steel. Another knifemaker boasted about his extensive heat treatment protocol that would lead to the best performing hunting knives available. read more

Edge Retention, History - Articles - Books, Steel and Knife Properties, Steels, Super Steels, Toughness

Super Steels vs Regular Knife Steels

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Super Steel

I see frequent references to “super steel” online, and I was curious about how long that terminology has been around. I did searches on bladeforums as it is one of the oldest knife forums. The number of references to “super steel” has increased over time, but so have the number of posts on bladeforums. I saw how many references to “super steel” there were in each year, and then as a proxy to how many posts there were on bladeforums I did a search for “154” and saw how many references there were each year. Google tops out at 200 results but at that point the dataset was big enough to get an idea: read more