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. NOTE 1 The conversion tables in Annexes B to G are based on empirical results which were evaluated by means of regression analysis. Such analysis was not possible in the case of the values given in Annex A because a sufficient number of results was not available. NOTE 2 Annex H gives information about the effects of changes of the test procedure in the standards specifying the hardness tests. 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. Sections of this International Standard are reprinted, with permission of ASTM International, from ASTM E140 Standard Hardness Conversion Tables for Metals Relationship among Brinell Hardness, Vickers Hardness, Rockwell Hardness, Superficial Harness, Knoop Hardness, and Scleroscope Hardness.