6 Grades of Steel Used for Making Knives

Oct 25th 2018

Knives are one of the most versatile, long-lasting tools in your kit. The right one helps you prepare your food, clear your surroundings, or even save your life; and with proper maintenance, it will last for years to come.

You can't always tell by just looking at it, but there are several different kinds of steel used to create your knife's blade.

If you've ever wondered things like what makes M390 steel knives wear-resistant, or what to use for saltwater applications, here are some of the key reasons.

Composition of Steel

Although there are thousands of kinds of steel, they're all primarily composed of iron and carbon. Iron is the main ingredient, with carbon only taking up between 0.002% and 2.14% of the total weight.

Over time, blacksmiths and steel manufacturers have learned that adding other elements can change how the metal behaves. Additives such as chromium can make it harder, nickel helps the final product resist corrosion. Steel used in tools will often contain molybdenum, tungsten, and vanadium.

You don't have to know the name of each element or how it affects the steel. Just keep in mind that the composition of steel can be manipulated to alter the qualities of its final product.

Characteristics of Steel

The characteristics of your knife will determine how it should be used. For example, a very hard steel would be a good choice for blade retention, but it probably wouldn't resist rust too well; such a knife would be better suited for home use than for outdoor tactical purposes. When purchasing a knife, you should pay attention to:

  • Corrosion resistance is how well the material withstands natural deterioration such as rust.
  • Ductility describes how well the metal bends and flexes without fracturing.
  • Hardness is how well a blade resists being permanently deformed.
  • Wear resistance describes how well the blade stands up to abrasion.

Common Grades of Steel

Even though there are so many kinds of steel used to make knives, some are used more frequently than others. Below is a list of the most common ones and a short description of their composition and use.

  • 1095 is the most common high-carbon steel used for knife blades. It's composed of roughly .95% carbon and .4% manganese. It holds a good edge, is easy to sharpen but not very tough. It also rusts easily, though this can be combated with good maintenance.
  • 5160 steel is plain carbon steel mixed with a bit of chromium for added strength. It's comprised of .56-.64% carbon.
  • A2 steel is often used for custom combat knives. It has a high carbon content (0.95-1.05%) with low chromium (less than 5%). It's a tough steel that requires regular maintenance to resist rust. A2 steel is used for tools as well as knives.
  • D2 steel has a high chromium content making it highly rust resistant. It's also a very tough steel with 1.50-1.60% carbon. Knives of D2 steel keep an edge well but can be difficult to sharpen. They're also near impossible to polish to a mirror finish.
  • L6 is often used in cutlery and saw blades because it holds an edge and is very tough. It does, however, need significant maintenance to keep it from rusting.
  • M390 contains lots of chromium and vanadium.

The M390 steel knives for sale online and elsewhere are extremely wear-resistant, hold their edge well, and resist corrosion.