railway RRB JE (CBT I + CBT II) Mock Test 2024 Strength of Materials Simple Stress and Strain Mechanical Properties
For applied load P (Newton), diameter of ball D (mm) and diameter of indentation d (mm), the Brinell hardness number is given by
1
\({B{HN}} = \frac{2P}{{{\pi D}{}\left( {D - \sqrt {{D^2} - {d^2}} } \right)}}\)
2
\({B{HN}} = \frac{P}{{{\pi D }{}\left( {D - \sqrt {{D^2} - {d^2}} } \right)}}\)
3
\({B{HN}} = \frac{2Pg}{{{\pi D}{}\left( {D - \sqrt {{D^2} - {d^2}} } \right)}}\)
4
\({B{HN}} = \frac{2P}{{{\pi Dg }{}\left( {D - \sqrt {{D^2} - {d^2}} } \right)}}\)