Tatsuya Ishibashi

The influence of different mechanical properties of the spherical indenters on hardness.

Hardness is influenced by the different mechanical properties of the spherical indenter in the elastic-plastic transient indenting process. To clarify that point, we indented steel and tungsten-carbide spherical indenters in the several standard blocks for hardness. In order to establish the relations of the elastic-plastic transient indenting process experimentally we related the hardness Pm(mean contact pressure) with a true profile coefficient of the permanent indentation : (d/Dp), not with an apparent profile coefficient : (d/D) used traditionally, and formulated as follows ; Pm=Pup(d/Dp)xp. We can calculate the hardness affected by the different mechanical properties of the spherical indenter using this formula for arbitrary conditions. Further, we compared the Brinell hardness obtained by Yoshizawa with our calculated values, and we obtained a good coincidence between them.