Category: Heat Treating and Processing

3 thoughts on “Heat Treating and Processing”

  3. Ciao Larrin,trovo molto utile questo sito,
    Avrei una domanda riguardo all’acciaio A8mod:come é meglio temprarlo per raggiungere la massima durezza?

    Reply

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Carbides, Corrosion Resistance, Niobium-Alloyed, Nitrogen-alloyed, Powder Metallurgy, Steel and Knife Properties, Super Steels

What is the Future of Stainless Knife Steel Design?

Larrin

Thanks to Aram Compeau, Gordon Olafson, and John Walton for becoming Knife Steel Nerds Patreon supporters! I have an update on Patreon about the “rare earth” elements in AR-RPM9 steel.

I completed a minor revision to my new book Knife Engineering to correct a few typos. Some readers outside the USA also asked for more conversions from Fahrenheit than were present originally, so I incorporated both Celsius and Fahrenheit everywhere in the book in the text and tables, though some images and charts still have only one temperature scale or the other.  I wouldn’t say that the changes in the revision are big enough to buy a new one if you have it already, this is not a new edition, but if you haven’t purchased one yet this is as good a time as any. read more

Heat Treating and Processing, Steel and Knife Properties

13 Myths about Heat Treating Knives

Larrin

Thanks to Lee Rothleutner and J Hamm for becoming Knife Steel Nerds Patreon supporters!

General Heat Treating Myths

1. Heat Treating is the most important factor for high performance knives. This one started out along the lines of “even the best steel will perform poorly if given a bad heat treatment,” and that I can’t disagree with too much. However, it has become somewhat fashionable to talk about knife performance as entirely (or almost entirely) controlled by the knifemaker’s skill in heat treatment. This has some truth to it as knifemakers who use a subpar heat treatment will certainly have subpar performance. However, the heat treatment can only do so much. No heat treatment is capable of making high carbide CPM 15V into a high toughness steel. No heat treatment can turn 1095 carbon steel into a stainless. And I would argue that the single most important factor for knife performance is the edge geometry rather than the steel selection or heat treatment. The edge geometry greatly controls the cutting ability and edge retention of the knife and also resistance to chipping and rolling. The image below shows measured edge retention of 154CM knives with different edge angles so you can see the vast difference in measured performance (higher number means more cardstock cut). Of course, focusing on any one of these factors at the expense of the others: steel selection, heat treatment, and edge geometry, is a mistake and each should be optimized for the given knife. But if we were to pick one factor that is the “most important” I’m not sure that heat treatment would be the one. read more

Forging, Toughness

Toughness Improvement of High Carbon Tungsten Steel 1.2562

Larrin

Thanks to all the new Knife Steel Nerds Patreon supporters that have joined since our big article on CATRA testing. The response has been phenomenal. We only need 4 more supporters to reach 200! Brandon Percival, Jason Stone, Fixall, John Schmidt, Adam Ringgenberg, Adam Webb, Shah Paul, Andy, Chad Shoopman, Dylan Giagni, Adam Nolte, John Scarborough, Datafox, Ben Secrist, Noah, Josh – REK, Robert Towe, NJO, Dd, Andrew Bounds, Nathan Gee, and hsc3. read more

Forging, Toughness

Ranking Toughness of Forging Knife Steels

Larrin

Thanks to Dinkma, Gavel John, and Roger Rozenberg for becoming Knife Steel Nerds Patreon supporters!

Low-Alloy Steel Testing

Over the past two years or so we have tested the toughness of many knife steels using a simple charpy impact test. You can read about the specifications of the test on this page. With the samples tested in this article I got a lot of help from Warren Krywko and Devin Thomas as well as donated steel from Alpha Knife Supply, Barmond Special Steels, and Achim Wirtz. This article focuses on the toughness testing performed on “low alloy” and carbon steels that are often used by forging bladesmiths. It is possible to forge high alloy steels, of course, though it does not appear to be very common even today. read more

Heat Treating and Processing, Steel and Knife Properties, Super Steels

Friction Forged Knives – Diamondblade Friction Stir Processing

Larrin

Thanks to Keith Coleman, Paul Bruno, Lotiel Vardamir, and Lennart Palkovits for becoming Knife Steel Nerds Patreon supporters!

Friction Forged Knives

The company DiamondBlade Knives produces knives with friction stir processed (FSP) edges [1]. Diamondblade Knives is a sub-company of Knives of Alaska. They use conventional D2 tool steel and process the edge so that it has hardness of around 65-69 Rc and a spine at 38-42 Rc. The knives are advertised as having a finer grain structure than powder metallurgy stainless steel and superior edge retention, toughness, and sharpness than knives tested in 12 other blade steels including S90V. And that the friction forged edge is stainless unlike conventionally processed D2. So I am going to detail the process used to produce the knives and what the properties of the steel likely are. read more

Heat Treating and Processing, History - Articles - Books, Steel and Knife Properties

S35VN Steel – Properties and How to Heat Treat

Larrin

Thanks to Konstantinos Noulis, Neil MacEachern, and J Kane Searcy for becoming Knife Steel Nerds Patreon supporters!

S35VN Steel History

S35VN is a steel developed and produced by Crucible Industries, released in 2009. The steel was developed by Maria Sawford as a modification of S30V by reducing the vanadium content, adding 0.5% niobium, and removing the nitrogen addition (incidental nitrogen is still present). Powder metallurgy steels typically have at least 0.03% nitrogen [1][2]. These changes led to a steel with improved toughness and machinability relative to S30V at the cost of some edge retention. Heat treatment response and corrosion resistance remained approximately the same as S30V. More information on the history leading up to S35VN can be seen in this article on the newer S45VN. read more