What is the hardness of wear plates?

The quantity of carbon content mixed in the steel determines the hardness of the wear plates. More carbon content present in the material means more hardness. When carbon is trapped in the iron crystal lattice, martensite steel is formed which is the hard and brittle phase of the steel. Carbon helps in improving the strength of iron by distorting its crystal lattice. The inclusion of carbon makes the material highly tensile and tough. However, due to high hardness, the materials become malleable. 

Wear plate manufacturers build steel wear plates through the quenching and tempering process of forged steel blocks. In the quenching process, steel is brought to a high temperature and then cooled rapidly which in turn forms grains within the steel, increasing hardness.  In the tempering process, the quenched steel is re-heated to a below-critical temperature and then allow it cool off at room temperature. This prolonged cooling process helps the crystal structure in reforming which as a result increases the hardness and toughness of the steel.

Brinell Hardness Number (BHN) is the measurement of the level of hardness of the material. The BHN of a material is directly proportional to its hardness level. 

AR300 steel grade has a hardness level of (270 – 390) BHN.

AR400 steel grade has a hardness level of (360 – 444) BHN

AR450 steel grade has a hardness level of (420 – 480) BHN

AR500 steel grade has a hardness level of (477 – 534) BHN