All Steel is Not Created Equally

Steel Armor is typically hot rolled into sheets from a steel billet. The rolling allows for a homogenizing and aligning of the crystalline structure of the steel. The plates are heated and rapidly cooled by oil or water quenching. This process is called Austenitizing and results in a through hardened product. The armor is then tempered to decrease brittleness and increase the steel’s ability to be formed, or ductility.


Not all high hardness steel should be armor. You can often find high hardness steel at your local metal supply outlet, AR450 or AR500, but this is not the same as the armor steel that is used for our body armor. The AR stands for abrasion resistant, and the numerical portion of the name indicates how hard the steel is on the Brinell hardness scale. 500 Brinell equals 51-52 on the Rockwell C hardness scale. We use AR550 steel that is 10% harder and is produced at very tight tolerances. Our AR550 steel is used in several U.S. military projects and requires guaranteed physical properties.  While the steel sold at your local supplier may have some of the hardness of our steel armor, it will not have the same characteristics necessary to be good armor and hardness only paints part of the picture. The cheaper steel while being relatively hard does not have the same ability to be formed or the toughness required to consistently stop higher velocity threats. That steel is designed for service use on heavy equipment, such as loaders or mining equipment and is not manufactured with the tolerances and characteristics required to make high performance armor. 

The AR550 steel that we use for our body armor is the best steel that we can currently find. It forms well without cracking and retains required hardness without being brittle. We have tested samples of armor steel from all the major domestic and European manufacturers and have found that we are currently using the best steel available. Our AR550 steel at Oregon Ballistics, an independent NIJ certified lab, tested better than all other AR550 armor steel we tested and even outperformed an AR600 armor offered by another steel supplier. In fact, our AR550 had 5% better ballistic capability on hard to stop projectiles like the M193 than the supposedly better AR600.

There are many options for body armor out there, but you can rest assured that when you purchase steel armor from Caliber Armor you are receiving the best steel that we can possibly use. It may cost us more, but our customers lives are worth it.