Measurement methods of each hardness indexes are theoretically analyzed.
These analyzing makes equations to show relationships among hardness indexes.
However, some of them is too complex to obtain inverse functions.
Those complex equations are approximated by 4th degree functions, 6th degree functions and so on.
Approximated equations are used in this application.
Calculation results of this application are different from those of ASTM's Hardness conversion table on some part.
Following 14 indexes are able to be converted.
- Tensile strength
- Vickers hardness: HV
- Brinell hardness: HB
- Rockwell hardness: HRA，HRB，HRC，HRD
- Shore hardness: HS
- Superficial Rockwell hardness: HR15N，HR30N，HR45N，HR15T，HR30T，HR45T
When you would like to know the conversion result according to ASTM, it is easy to check the ASTM's hardness conversion table.
There are many tables on the internet.
However, the hardness conversion is not good by rights.
It is the best way to measure the hardness index with the hardness measurement instrument for the index.
Reference:
Sadao YAMASHIRO and Yukio UEMURA, On the Conversionbetween indentation Hardnesses, Transactions of the JSME，Vol.27，No.176（1961）pp.430-438(in Japanese).
Tadasu TSUKIZOE and Terumasa HISAKADO, On the Theroretical Analysis of Shore Hardness, Transactions of the JSME，Vol.30，No.212（1964）pp.531-538(in Japanese).