The conversion table In this Standard applies
– to hardness values determined according to the following standards:
~DIN 50 103 Part 1 and Part 2 (Rockwell)
~DIN 50 133 Part 1 (Vickers) and
~DIN 50 351 (Brinell)
– to tensile strength values determined according t.o
~DIN 50145 and
– to values of HRD hardness not standardized in German standards.

Subject to the restrictions mentioned later, this conversion table applies to unalloyed and low alloy steels and cast steel in the hot formed or heat-treated condition. In the case of high alloy and/or work-hardened steels, substantial deviations are likely in the conversion.

Conversion between hardness values or from hardness values to tensile strength values essentially involves inaccuracies which have to be taken Into account. Extensive studies have shown that It Is impossible to convert from one to another hardness values determined by different methods even when they have been determined with extreme care, on the basis of a relationship that is valid for all metallic materials or even merely for all grades of steel. This stems from the fact that the indentation behaviour of a material is determined by Its stress-deformation behaviour in a very complex manner. A given conversion relationship will therefore provide better agreement, the closer is the stress-deformation behaviour of the material under test to that of the materials used for deriving the conversion relationship.