Influence of different placement of hardness penetrations on calibrating Rockwell-hardness tester by hardness reference blocks

The hardness reference slabs used for the calibration of Rockwell hardness testing devices will deform by buckling due to increasingly deep marks left on the slab surfaces during the hardness tests, the buckling becoming more significant with lower degrees of hardness and highly dense structure of testing patterns. The article presented here illustrates the results of a study using a modified, computer-automated hardness testing device with high-precision penetration depth measurement using a LASER interferometer, showing that the effect of buckling on the hardness data to be measured may not be neglected. (orig.)