2020 in Review: Knife Steel Edition

2020 had a lot going on, of course. But a lot of good came in the area of knife steel. Let’s go through some of the highlights.

New Steels

The big announcement in terms of new steels was the Spyderco-exclusive CPM SPY27. This steel was announced in January of this year, and I offered early analysis based on the released composition here: CPM SPY27 Analysis. That wasn’t the end of my SPY27 coverage, however, as I was able to get a bar from Spyderco and Niagara Specialty Metals and perform a range of experiments on it, including hardness, corrosion resistance, toughness, and microstructure evaluation. Read the results of my experiments here: SPY27 Testing.

New Experiments

One of the most exciting datasets this year was the big set of CATRA edge retention experiments that were completed along with knifemaker Shawn Houston. We were able to test over 50 knives with a large range of steels to compare the edge wear characteristics of all of them. This study was very fun and very popular, I’ve seen it shared across the internet. This study helped answer some questions about the response of different microstructures to edge wear and raised a couple other questions as well. Cryogenic processing and high temperature tempering were not found to improve edge retention which have been frequently claimed in the past. However, the strong effect of vanadium on edge retention was confirmed, as expected. This study (and others on this website) wouldn’t have been possible without my Patreon supporters, as it was by far the most expensive study I have completed.

I was finally able to do a full range of analysis on the relatively new Bohler M398 steel this year. The steel was confirmed to have excellent edge retention in combination with very good corrosion resistance and hardness. However, the microstructure is relatively coarse for a powder metallurgy steel and the toughness was quite low.

Another relatively new steel that I finally got around to testing was Uddeholm Vanadis 8. Despite my initial skepticism, Vanadis 8 showed a clear improvement in toughness over CPM-10V with only a relatively small decrease in edge retention. It has taken over CPM-10V as my favorite “high edge retention” non-stainless steel.

One question that always interested me was whether the “3rd Generation” powder metallurgy technology used by Bohler and Uddeholm led to differences in properties or whether this was just good marketing. I compared the microstructure, toughness, and impurity content of Crucible, Carpenter, Bohler, and Uddeholm steels to find the true differences between these different companies.

I also wrote new articles on specific steels with a writeup of the history of their development and many experiments such as the following: CPM-S35VN, CPM-10V, M390, CPM-S30V, CPM-S110V, CPM-S90V and CPM-S125V, CPM-S60V, and D2/PSF27/CPM-D2.

New Book

Another exciting new release this year was my book, Knife Engineering: Steel, Heat Treating, and Geometry. This was my attempt to offer an all-in-one book for learning about what makes steels different, how to heat treat, what happens during every step of heat treating, and the effects of edge geometry and design on knife performance. The response to the book was overwhelming; the book is way more successful than even my most optimistic dreams hoped for. The book now has many, many positive reviews on Amazon and social media and I continue to receive very complimentary messages from knifemakers and enthusiasts who are enjoying the book. Thanks everyone for making the book a success.

New, New Steels

2021 is going to be the year of knife steel development. A steel of my design was produced by Crucible this year and the first rolling stage was completed by Niagara Specialty Metals. I had an article this year on what my vision is for the future of knife steel, and we will see soon how successful we are in achieving it. I also have a couple other projects in the works that I hope to make announcements about soon.

Summary and 2021

As you can see this was a big year despite the many challenges that we experienced in 2020. SPY27, the big CATRA study, and my new book were the highlights for me. I’m very excited for the future with all of the new steel development going on next year. I also got a salt pot furnace recently and I would like to do some experiments with marquenching and austempering (bainite). More to come!

Miscellaneous

I want to briefly highlight a few of the odd topics I was able to cover this year. Some I have been waiting for some time to cover and was happy to finally get to them, including:

Friction Stir Processing of Steel (Friction Forged Diamondblade Knives) 

Friction stir processing has been an interesting niche topic to me so I did a review of literature on how the technology works and what the potential advantages are.

Ranking Toughness of Forging Knife Steels

“Forging” or low-alloy steels surprisingly have some of the most complex behavior when it comes to toughness. Some steels that I would think would have high toughness are much lower than expected do to factors that don’t usually come up with high alloy steels, like “plate martensite.” I summarized the experiments we have performed so far and gave a high level view of why the steels act the way they do.

How to Heat Treat CPM-154

I did a series of experiments on CPM-154 to find the optimal set of heat treatment parameters to maximize properties. I also tried to find an optimal high hardness heat treatment for those that are interested in a high strength stainless steel.

Toughness Improvement of 1.2562 Steel

This was an interesting study by Marco Guldimann that had some intriguing results on improving low-alloy, high carbon steel toughness. The reasons for the improvement are still not completely clear and I am hoping that I can do some experiments with “marquenching” to help narrow down the source of improvement.

What is the Best Budget Knife Steel?

I looked at a range of conventionally-produced steels (as opposed to powder metallurgy) to see which steels had the best combinations of properties. To me there was a clear winner, though it depends somewhat on what properties are most important to you.

Who is the Greatest Knife Steel Metallurgist of All Time?

I looked at the greatest contributions of different metallurgists to the steels we used for knives. And I stated who I think made the greatest contributions as well. There is a lot of interesting history to steel and this article is a good place to start when learning about it.

13 Myths about Heat Treating Knives

This was somewhat of an introduction to heat treating, starting with a list of misconceptions about it. Maybe a few are surprising even to experienced knifemakers. There are links within the article to more in-depth topics related to heat treating.

The Companies that Bring Us Knife Steel

I covered how the knife steel industry works when it comes to sales and distribution of steel, focusing on knife steel suppliers. This is an area that knife enthusiasts don’t get into much but is very important to knifemakers in terms of what steels are available to them.

Lost Knife Steels – Questek Ferrium M60S

M60S got some buzz when it was first announced, as a steel which was developed for knives using modeling software. It never went anywhere, so I explored the metallurgy behind the steel design and why it failed.

Steel Properties that Knifemakers Care about and Users Don’t

There are a lot of steel characteristics that knifemakers are looking for that the end users/buyers don’t pay attention to. For those that want a look into the knifemaking world you can find it in this article.