Hardness testers measure at a millionth-of-an-inch resolution with large forces-picture an exceptionally accurate micrometer being closed with 330 pounds of force. The smallest "give" in the unit's frame, the sample, or contamination on the sample or anvil can give bad results. With a closed-loop system, the operator is not aware of deflection any more than he is using an old knife-edge unit. Fortunately, there is an answer for this problem too, through deflection compensation. This eliminates the effects of deflection resulting from contaminating materials on the sample and anvil, or from the sample itself deforming or compressing under load-as in a cylinder. This feature makes hardness testing more repeatable in actual operating conditions, not just during calibration routines.
Brinell testing has seen tremendous improvements automating each aspect of test method ASTM E-10. The Brinell method traditionally has suffered from several problems: a lengthy two-or-three step process-indentation then measurement-often preceded by grinding. There has been a gross lack of accuracy and repeatability-mostly due to operator influence in the test measurement.