Q: What are the differences between steel types in blades? If you have collected knives for a long time, or even if you are new to knives, chances are you have wondered what the differences are between all the types of steel in knife blades. There are lots of different types of steel, and no doubt you have wondered what the best steel is. This resource should help you understand what types of steel should be used for what purposes, and hopefully that can help you make a more educated decision on what steel to use.

All that is needed to make basic steel is a combination of iron and carbon. However, over time it was found that adding different elements to this basic steel substance can increase its toughness or hardness. These added elements account for what is the major difference of most types of steel in blades. It was quickly discovered that there are advantages and disadvantages to each added element. For example, a certain alloy might make a blade harder. The more hard the steel, the longer it will hold its edge (and that means less frequent sharpening), which is great! However, if you harden the blade, you also make the blade less tough, which means the blade is less resistant to shock and impact (not such a good thing). Unfortunately, a blade cannot be both harder, and tougher; as you add toughness, you make the blade less hard and vice versa. Since not all of us have the basic training of a materials scientist, here are a few key differences in steel types that will help you decide what type of blade is best for you.

Ingredients of Steel

First, I will introduce you to the basic ingredients of steel and their uses.

Carbon - This ingredient is essential to steel’s creation; all steel will have some amount of carbon. It is the most important hardening element, but as it is added it can reduce the toughness of the material. Carbon reduces the amount that the knife will wear over time. So, the amount of carbon in the blade tells you a lot about the quality of the steel. Low carbon means there is (.3% or less), medium has between (.4-.7%), and high is (.8% and above). Chromium - Combats corrosion. Stainless steel knives will have chromium as a major ingredient, typically at a minimum of 12%. Chromium will also increase the strength of a knife, but adding chromium in large amounts decreases toughness.

Cobalt - Strengthens the blade.

Copper - Combats corrosion.

Manganese - Hardens the blade. If added in high quantities it can increase brittleness.

Molybdenum - Maintains the steel's strength at high temperatures.

Nickel - Adds toughness.

Nitrogen - This element is sometimes used as a replacement for carbon in steel.

Phosphorus - Improves strength.

Silicon - Increases strength. Also, removes oxygen from the metal while it is being formed.

Sulfur - Increases machinability but decreases toughness.

Tungsten - Increases wear resistance.

Vanadium - Increases wear resistance and makes the blade harder.

Types of Steel

There are literally thousands of types of steel. Among them, the most common are carbon steels, alloy steels, tool steels, and stainless steels. Each of these types of steel has a designation system that gives them a specific number. I will give you one example: In the SAE (Society of Automotive Engineers) designation system, carbon steel and alloy steel are designated by a four digit number, where the first digit indicates the main element, the second digit indicates the secondary element, and the last two digits indicate the amount of carbon, in hundredths of a percent by weight. So, this means that 1095 steel would be .95% carbon. In addition, in the SAE system any steel starting with a letter is classified as tool steel.

Plain carbon steels are steels that contain iron, carbon, and a small amount of manganese. In contrast, alloy steels have a specified composition and contain certain percentages of vanadium or molybdenum, and they also typically have a larger amount of manganese. Tool steel contains tungsten, molybdenum, and other alloying elements.

I. Plain Carbon Steels

The 10XX (1045, 1095) Steels - 1095 is the most common 10XX steel (or "high carbon" steel) used for knife blades. Steel in the range 1045-1095 are used for knife blades, although 1050 is more commonly seen in swords. 1045 steel has less carbon (.45%), where 1095 has more (.95%), inversely 1095 has less manganese and 1045 has more. So in essence, 1095 steel would have more wear resistance, but would also be less tough. 1045 holds an okay edge, 1095 steel holds an edge great, and is easy to sharpen. The major drawback to this type of steel is that it rusts easily. Because of this issue, you will often see 1095 blades with some type of coating to combat rust. If you buy a knife with this type of blade, be sure to store it well and you should have no problem.