The ASTM E140-2012B standard provides metal hardness conversion tables covering the conversion relationships between brinell hardness, Vickers hardness, rockwell hardness, surface hardness, Knoop hardness, rebound hardness, and Richter hardness. These conversion tables are suitable for non-austenitic steels (including carbon steel, alloy steel, and tool steel) in forged, annealed, normalized, and quenched and tempered states, as well as nickel and high-nickel alloys, cartridge case brass, and other materials. The conversion table is designed to help users accurately convert between different hardness testing standards to suit different industrial application needs.