GB -T 24186 NM450 Wear resistant chrome steel chart. The AR400 plate Brinell Hardness Number is BHN Typically which signifies the fabrics degree of hardness. AR400 abrasion resistant steel plate is created from high-carbon alloy metal plate material. Abrex 400 materials is very harder due to the addition of carbon, and formable and weather Products Abrasion Resistant Steel Plate GB T 24186