A Technical Explanation of the Steel Ingredients of Chef Knives
Yeah, yeah you say “the knives are made out of steel…so why should I care?” Actually as long as it cuts through whatever you are trying to cut, then basically you shouldn’t care. Other than basic curiosity, and when that sucker fails to cut. Which in most cases is about 6 months after you bring it home from the store. You see the kind of steel that is used in the manufacture of a kitchen knife has a direct influence on how long the blade will hold its edge and on how easily you will be able to get it sharp again!
So yes, you probably want to know, especially if you are about to make an investment of a couple of hundred dollars or more. The simple addition of trace elements can make a tremendous difference in the strength and durability of a knife blade. Lets take a look at an historical story.
You have probably heard about Damascus Steel. It seems that during the first crusade the crusaders had battles with swords that literally broke in half as they fought their enemies. The European swords for that first crusade were so poorly made that they shattered against the superior steels of the moslems. When they returned you can bet the sword-smith’s went back to the drawing board to figure out what process was being used to make such excellent steels.
By the way they never did figure it out. It took until the middle of the 20th century to explain the ingredients of the steel. It turns out that the ores that were used by the Saracens naturally contained all the correct trace elements of chromium, vanadium and whatever else that made the steel incredibly hard. That coupled with process of heating and pounding, then folding the steel back upon itself and pounding again with proper tempering or quenching produced a far superior steel. Incidentally, when the Saracens exhausted that ore pit, they never made knives that strong again.
Fast forward to the 20th century with all the thousands of uses that steel currently has, from skyscrapers to automobiles and the bridges they travel over; modern steel has many different formulations. In fact the engineers have it to a point where they can do the calculations for the required durability and strength and specify the exact formula for the steel they need.
This means the knives of today are not the type that grandma had to live with 50 years ago. Today you can buy a chefs knife made with literally hundreds of different formulas. The formula itself does not matter, it is the results you are looking for. What is in the knife that is going to keep a strong edge? How often will you have to sharpen it, and if it looses that sharpness how hard is it to put the edge back?
Grandma’s knives tended to be harder steels. you don’t necessarily want something that is above 62 on the Rockwell scale. The harder the steel the more difficult it is to sharpen. However, a hard steel knife will hold an edge for a much longer period of usage. Straight carbon steel with few extra additives is the best knife steel due to the fineness of the grain. It may be formulated to be a little softer, but you can also easily restore the edge with a few strokes on a high grit sharpening stone.
Digital Tester From Wikipedia Creative Commons
Some manufacturers use pattern welding (Damascus Style) to place a softer, prettier looking layer over a core of harder carbon steel. These knives will be more expensive due to being hand forged and the complexity of the operation. Shun and Zwilling-Henckels are a few of the popular examples of this, but there are many many more available, mostly from Japan.
There are plenty of great knives on the market that are made from just one formula usually, some form of tool grade steel. These can be hand forged (individually formed and tempered) or stamped from a special sheet and processed by machine. Obviously, these will be less expensive but you can still find some very high quality in the German and French brands. Henckels, Forschener and Sabatier are a few examples. The list here is also quite long.
If you follow all the links on this page you are in for a huge education on knives. The bottom line is that you want a knife that you are comfortable using. You want to be able to put an edge on it by yourself rather than have to send it back or to a sharpener. Investing in a good sharpening stone and learning how to use it will save you lots of headache later on when the blade inevitably grows dull.
If you wish to find the ingredients of the exact steel in your knife, you can take the name of the formula and go to the Interactive Knife Steel Composition Chart here you will find the technical information of all uses that a particular steel is used for.
Michael Brown
Take it away boys……
Knife Steel – What Goes In Knife Steel?
Informative article about knife steel, the elements that are used in knife steel and what those elements do.
We use the term Knife Steel in this article. However, most of the information applies to steel in general. Steel is iron with no more than 2% carbon in it. The higher the carbon in knife steel the harder the blade can be made. The harder the steel the sharper the edge the knife can take. The quality of the heat treatment on knife steel has a big impact on blade strength. When lesser quality steel is properly heat treated the result can be a blade that is stronger than a blade made from higher quality knife steel that had been improperly heat treated. Most knife steel is tempered martensite which has a fine grained crystal structure with lattice irregularities that make it hard.
Several elements can be added to steel to produce different traits. What follows is a list of elements commonly added to knife steel and their purposes.
Carbon: This is the most important element to be added to steel for hardening the steel. Knife steel should have greater than % carbon, which would make it high carbon steel. Carbon steel usually means few or no alloy ingredients have been added. Knife steel with a high carbon content but low chromium content is prone to rusting and pitting if not kept dry and oiled.
Chromium: This is added for hardening, and to increase wear and corrosion resistance. Knife steel with at least 13% chromium is considered stainless steel.
Cobalt: Cobalt is added to knife steel to increase the strength and hardness. It permits quenching at higher temperatures and intensifies the individual effects of other elements in more complex steels.
Copper: Copper is added to increase the corrosion resistance. 
Manganese: Manganese is added to knife steel as it aids the grain structure and increases the ability to harden the steel. It also increases the strength and wear resistance. Manganese is present in most cutlery steel.
Molybdenum: This element helps prevent brittleness in knife steel and helps the steel maintain strength at high temperatures. It makes the grain size in the steel smaller which improves the hardness and toughness.
Nickel: Nickel is put into knife steel to increases the strength, corrosion resistance and toughness of the steel. The term corrosion resistance is used because all steel will eventually corrode if it is not cared for properly.
Nitrogen: Nitrogen can be used in place of carbon in knife steel. The Nitrogen atom works similar to carbon but offers the advantage of corrosion resistance.
Silicon: Contributes to the strength of knife steel.
Tungsten: Tungsten is added to knife steel to improve the strength, toughness and hardenability of the knife steel.
Vanadium: Increases the wear resistance and ability to harden knife steel. Like Molybdenum it makes the grain size in the steel smaller which improves the hardness and toughness of the steel.
There are several types of steels that are commonly used by the major manufacturers to make their knife blades. D-2, 420, 440, 425, AUS. These types of knife steel and others will be discussed in another article.
For additional information on this or related topics visit: www.NorthAmericanKnives.com or www.SwissArmyKnifeMall.com
| By Kirk McCormick Published: 1/16/2007 |
Update: For the most compprehensive tutorial on knife sharpening read this article by Chad Ward (long article)
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