Blade Steel

I get asked by customers and other makers, "What is the best blade steel?" Answer, "it depends." The issue with steel is that it only needs .6% carbon to get hard enough to make a blade that holds an edge. The American Iron and Steel Institute (AISI) Society of Automotive Engineers (SAE) had for a time standardized categories of how steel is labeled, though that standardization is not followed very much today, it still gives a starting point for understanding steel. The labeling is done in four numbers, the first two listing the category that the steel falls into (example: 10XX is simple alloyed steel, 50XX is chromium alloy steel), the second two numbers give the percentage of carbon in that alloy. 52100 is a steel that is used in bearings, this by its designation "5" is a chromium steel, the "100" means that it has 1% carbon in the alloy. 1075 is a simple carbon steel used in farm applications, the "10" designates it as a simple alloy, and the "75" means that it has .75% carbon in the steel. Nowadays steel manufacturers have stepped away from the AISI ratings and have created many of their own depending on the manufacturer, though many follow a general format. Tool steels are designated with an alpha numeric system (W2, O1, D2 ....ect) with each letter designating what the steel category is, stainless steel is all over the place, it's best to just look up the heat treat sheet or melt sheet on it and look at the carbon content. That was a lot of words to say just this, steel needs .6% carbon to hold an edge, the rest of the alloying metals are added to introduce other characteristics into the steel. The aforementioned 52100 bearing steel has specified amounts of alloying elements to give it wear resistant properties, allowing it to rub against itself in your car and not wear down quickly, and causing you to have an accident. Because of its carbon content it can also be made into an instrument that will hold an edge. The key to this for makers is to experiment with whatever steel you chose and figure out how to get the best out of your steel by using the tools in your shop. What works in my shop will not necessarily work in your shop. For those buying knives, look up the melt sheet on the steel and see what is in it, chances are that it will have enough carbon in it. However, it may have such elements in it that makes it difficult to sharpen in the field, or not be oxidation resistant in salt water environments, because the steel wasn't designed for blades but for another purpose all together. I am not the first to write about this and will not be the last, the information is at your fingertips, take some time and do some research prior to making an investment in a custom knife or a specified steel for your shop.