Glossary of Blade Steels

The steel used to make knife blades is alloyed with other materials to enhance the steel's performance and longevity. Basic steel is known as plain carbon steel and contains mostly iron and carbon. Plain carbon steels provide excellent hardness and edge retention, but lack corrosion resistance and are prone to rust.

The addition of chromium to steel alloys makes them "stainless," i.e. more corrosion-resistant. However, blade steels lose performance as the ratio of chromium to carbon goes up, performance meaning edge retention and sharpening ability.

The highest quality blade steels are able to combine outstanding performance and longevity. All blade steel alloys adhere to material specifications and are designated with a corresponding number. These are some of the best and basic blade steel alloys:

420HC: a high carbon (HC) variation of a standard 420 steel, 420HC steels offer the excellent wear resistance of high carbon added to the superior corrosion resistance of stainless chromium steels. It can be hardened to a Rockwell hardness of Rc 58. 420HC knives are tough, sharpen well, and will hold an edge. Blades made from 420HC steel are good all-around outdoor knives.

420J2: this steel has a low carbon content, but its hardness is a little better than basic 420 steel, reaching a max of about Rc 56 to 58. Knives with 420J2 steel will display great corrosion resistance and moderate edge retention. This would be a low maintenance knife ideal for basic outdoor use.

440A, 440B, 440C, 440V: these are the best of the 400 series blade steels. 440A and 440B steels are better than lower 400 series steels, but not as good as 440C or 440V. 440C steels attain a Rockwell rating from Rc 56 to Rc 59, and are very strong and stainless. Compared to 440C, 440V steels fall slightly short in hardness, but are superior in edge retention.

ATS-34 and 154CM: ats-34 is a trade name for a steel owned by Japan's Hitachi Steels company. It's a step up from 440C, trading off slightly less corrosion resistance for even better edge retention, with an ideal hardness between Rc 59 and Rc 61. ATS-34 blade steel is used in the best commercial knives as well as by custom knife makers. An American steel equivalent to ATS-34 is 154CM.

AUS-8: aus-8 steel blades are in a comparable class to ATS-34, but offer superb corrosion resistance. The carbon to chromium ratio of AUS-8 steel is low, and its stainlessness is increased by the use of nickel, which is not used in many premium alloys. The tradeoff is less edge retention, but for the average consumer, this is a great steel. Its hardness varies from Rc 56 to 58.

Damascus: is valued primarily for its aesthetic and historical interest. The forging methods and varieties of steel used to create it result in visible surface patterns that are accentuated by acid etching. The strength and endurance of swords made from Damascus steel were legendary.

D2: a high carbon, low chromium steel that provides outstanding edge retention, hardness, and wear resistance. However, D2 does not qualify as a stainless steel because it has a chromium level of 12%, just short of the 13% needed for stainless status.

S30V: developed in the U.S. by Crucible, this is a superb all around steel for hardness, edge retention, and stainlessness. S30V steel blades are easy to sharpen and have a Rockwell hardness of Rc 59 to 61. S30V is superior to 440C, ATS-34, and D2 steels.

Titanium: titanium blades are practically maintenance free. Unlike steel, titanium blades do not contain carbon, meaning they are basically rustproof. Titanium's edge retention is outstanding, and its hardness exceeds that of steel.