Metrological Characterization of Hardness Indenter Calibration System

There are four main components constituting the conventional hardness scales, in all types of hardness measurements, from testing machines to standardizing ones: Force application, indentation size measurement, indenter and measurement cycle. To assure the quality, reliability and uniformity in hardness measurement in all over the world it is important to constitute traceability of each parameter to the base SI units and confirm the performance of the system as a whole. One of the most interesting subject to be discussed is the calibration of the geometrical properties of the diamond indenters used in Rockwell and Vickers scales, sphero-conical Rockwell and square-based pyramid Vickers diamond indenters. The indenters to be used in testing and calibration/standardizing machines are supposed to be in accordance with some international hardness standards, namely ISO 6507-2 [5] and ISO 6508-2 [2] for testing Vickers and Rockwell machines, respectively; ISO 6507-3 [6] and ISO 6508-3 [3] for Vickers and Rockwell calibration/standardizing machines, respectively, and relevant ASTM standards. This paper describes the metrological characterization of UME Hardness Diamond Indenters Calibration System and the traceability of each measured parameter subject to calibration.