Hardness Relationship

The conversion tables which are built in and supplied with every new Equotip instrument is not applicable for rolls at all. However, the two scales Ld (cemented carbide tip) and Le (diamond tip) are closely related and the conversion between the two varieties is fully reliable.

For the indentation methods the different measurements in HV, HRC and HB can be compared to eachother with confidence.

However, for the rebounding methods like Shore and Equotip the errors when making conversions are larger as the individual measurements are highly influenced by the material properties such as internal stresses. Forged rolls have higher internal superficial compression than cast rolls. This creates a higher rebound so the conversion cannot be done based on the same tables.

Today all roll makers and almost every customer roll shop is using the Equotip system for various hardness checking. Scleroscope Shore instruments do not exist anymore.

Please note;
The different hardness units are not linked to the normal metric system and are only related to its own instrument. As a result there is no direct mathematical conversion between different hardness units. This may create confusion.

Any use of a hardness relationship table will at best be a good approximation; only giving a comparative indication of relative hardness.