This International Standard specifies the principles of the conversion of hardness values to equivalent values in other hardness scales and to estimates of tensile strength. It gives general information on the use of the conversion tables. The conversion tables in Annexes A to G apply to - unalloyed and low alloy steels and cast steel, - steels for quenching and tempering, - steels for cold working, - high speed steels, - tool steels, - hardmetals, and - non-ferrous metals and alloys. Converted values obtained using this International Standard are only directly applicable to the exact material tested. For all other materials, they provide an indicator only. In all cases, the converted values are not intended as replacements for values obtained by the correct standard method. In particular, tensile strength estimates are the least reliable converted values in this International Standard.