Category: Hardenability
Which Quenching Oil is Best for Knives?
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YouTube
The following information is also available as a YouTube video for those that prefer watching to reading. The video might be more fun though there are more details and more discussion in the article.
O1 Steel – History, Properties, and How to Heat Treat
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O1 Steel History
O1 steel was developed in 1905 by Halcomb steel which was acquired by Crucible Steel a few years later [1][2]. However, the history is a bit more interesting than that. In 1876 a large Sheffield steel company, Sanderson Brothers, purchased Sweet’s Manufacturing Company’s Geddes Steel Works in Syracuse New York. American tariffs had led to a large reduction in exported steel from Sheffield, and steel output from the USA had also greatly increased to match. So several English steel companies setup production facilities in the US, including Sanderson Brothers. Sanderson Brothers was a very old Sheffield steel company, founded in 1776. Tool Steel development began to explode starting in about 1900 due to the recent discovery of “high speed steel” which you can read about here: The History of the First Tool Steel. The year 1900 was doubly significant because in that year there was a major consolidation of 13 of the major steel plants which used “crucible” steel production methods, accounting for 95% of the crucible steel production in the United States.
How Fast Do You Have to Quench? Hardenability of Steel
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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.