Three punch average --> hardness measurement

[Runus]

Hi

Can someone please describe what the meaning of three punch average is? This is in connection with Hardness measurements.
Thanks!

 

[redpicker]

Typically, particularly with API tubular specifications, a single Rockwell hardness value is defined as the average of three individual Rockwell readings taken in the same vacinity. That is, to obtian a Rockwell hardness value, you would take three "punches", or readings, in the same area and take the aritmatic average of those readings to obtain your hardness value.

rp