A word of caution!
Hardness Conversion or Equivalents:
Hardness conversion between different methods and scales cannot be made
mathematically exact for a wide range of materials. Different loads,
different shape of indenters, homogeneity of specimen, cold working
properties and elastic properties all complicate the problem. All tables
and charts should be considered as giving approximate equivalents,
particularly when converting to a method or scale which is not
physically possible for the particular test material and thus cannot be
verified. |