Corrosion Resistance, Nitrogen-alloyed, Steels

Nitrogen-Alloyed Knife Steels

Larrin

Thanks to Matthew Hoffman, Tryggvi, and Ron Dillon for becoming Knife Steel Nerds Patreon supporters!

In previous posts I have written about the process by which steel is hardened. The steel is heated to a high temperature phase called austenite, where carbides are dissolved and carbon goes into solution in the austenite. During rapid quenching the carbon is trapped between the iron atoms and a phase called martensite is formed. Martensite gains its high hardness from the distortions to the atomic structure that come from carbon in between the atoms.  read more

Steel and Knife Properties, Steels

Ranking the Steel Ranking Articles

Larrin

Note: I now have a steel ratings article of my own, read it here: Knife Steels Rated by a Metallurgist

Intro

Thanks to Stacy Apelt for becoming a Knife Steel Nerds Patreon supporter! Based on a poll of Knife Steel Nerds Patreon voting members, we have decided to purchase a small impact tester for knife edges. This will allow us to study the effects of steel, heat treatment, edge geometry, sharpness, etc. on chipping and rolling of edges. read more

Edge Stability

What is Edge Stability?

Larrin

Thanks to Keith Nix and Benaiah Brabant for becoming Knife Steel Nerds Patreon Supporters! The vote is still open on Patreon for what equipment will be purchased for future research. 

Edge Stability

I got help directly from Roman Landes in writing this article (Thanks Roman!). The content below is based on Roman’s book, Messerklingen und Stahl: Technologische Betrachtung von Messerschneiden (Knives and Steel: Technological Examination of Knife Edges), as well as discussions with Roman. However, since the writing is mine the ideas are naturally filtered through me. Any mistakes are my own.  read more

Sharpness

Sharpness vs Cutting Ability

Larrin

Thanks to Matthew Berry for becoming a Knife Steel Nerds Patreon supporter!

CATRA, Sharpness, and Cutting Ability

I got several good comments on the article about CATRA edge retention testing regarding sharpness and cutting ability. The edges tested with more acute angles (20° edge is more acute than 50°) started out cutting better and remained that way through the standard 60 cuts. However, the measured width of the edge with the worn 20° edges was larger than with the 50°. So this leads to a question: which was sharper? And if the 50° was indeed sharper due to its narrower edge then why was it not cutting as well? read more

Damascus, History - Articles - Books, Steels

Five Myths About Damascus Steel

Larrin

Knife Steel Nerds coffee mugs have been shipped to all current “Ultimate Steel Nerd” Patreon supporters. 

What is Damascus Steel?

There are two major steel types that are called Damascus:

1. Crucible, or Wootz, steel was first produced in India and Central Asia and produced into swords anciently from at least the 3rd century AD [1]. It is made by producing small ingots of high carbon steel that are then forged and thermal cycled in a specific manner to lead to carbide bands that produce the final pattern when the steel is etched [2][3]: read more

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