Hardness measurement is widely used in industrial applications for quality control and acceptance testing of products because it is fast, inexpensive and relatively non-destructive. Uncertainty evaluation is complicated because calibration procedures require the use of direct and indirect verification tests, but the effects on the measurand itself due to test parameters variations are difficult to predict, such as the force-time pattern, inelastic performances of Rockwell indenters and the numerical aperture for Brinell and Vickers indentations measurement. This paper starts by accepting as a matter of fact that standard specifications have demonstrated acceptable performance, indicating that their application is correct for most of the materials generally used. Accepting this premise, the next step was to try to translate the practice, confirmed by many years of experience, into the new language of uncertainty, strongly required by quality documents.

A conventional characteristic of hardness measurements is the strong dependency on the official definition of each scale. For this reason, and to assure a good connection between National Metrology Institutes (NMIs), scientific organizations (e.g., IMEKO1) and international organizations for standardization (e.g., ISO2 and OIML3), a new Working Group on Hardness (WGH) was created a few years ago under the Consultative Committee for Mass and Related Quantities (CCM) of the Comité International des Poids et Mesures (CIPM). One of the principal aims of the WGH is to analyze the level of accuracy corresponding to the state-of-the-art of national primary standards, ultimately leading to improvements in the hardness scale definitions and, at the same time, providing well-defined traceability, in terms of uncertainty, of industrial measurements. Recent efforts to improve hardness scale definitions and the consequential reduction of uncertainty are presented in this paper. Contributing to this effort are the NMIs that currently maintain hardness standards and those that have plans to realize them in the near future. By improving the definitions and the associated uncertainty, certain advantages will be obtained at all levels in the dissemination of hardness standards: from the calibration and testing laboratories to industrial measurement applications.

In this paper a methodology for calibration of force transducers used for hardness testers is described. The methodology associates to the standard procedure a method to evaluate and correct other effects such as promptness, creep and hysteresis. After a general description, a practical application is reported.

A numerical model of a general purpose commercial equipment for current versus voltage (I-V) and differential capacitance versus voltage (C-V) measurement of active devices is presented. The good agreement between the model results and experimental data show that the model takes into account the main error sources of the instrument and can be used as a base to perform error correction and to implement a calibration procedure.

The inrush currents generated during a energization of power transformer can reach very high values and may cause many problems in power system. In this paper method for controlled energization of power transformer based on measuring of remanent flux of magnetic core is presented. The remanent flux is measured and memorized at the last de-energization of transformer and then applied at next energization. Experimental results of inrush currents at controlled energization of transformer are presented.