| Zugriffsnummer | 16233 |
| Dokumenttyp | Konferenzartikel |
| Sprache | Englisch |
| Titel | Evolutions in hardness scales definition |
| Autor(in); Institution |
Barbato, Giulio; Politecnico di Torino, DSPEA, Torino, ITALY
Germak, Alessandro; Istituto di Metrologia Gustavo Colonnetti (IMGC), Torino, ITALY
Herrmann, Konrad; 5.102, Härtemessung, PTB-Braunschweig
Low, Samuel; National Institute of Standards and Technology (NIST), Gaithersburg, MD, USA
|
| Quelle/Jahr | Metrology in the 3rd millennium : XVII IMEKO world congress ; June 22 - 27, 2003, Dubrovnik, Croatia ; proceedings:(2003) |
| Availability | [CD-ROM] ; file name: TC5.pdf, S. 978-981 |
| Herausgeber(in) |
Ilic, Damir
|
| ISBN | 953-7124-00-2 |
| Verlag | Dubrovnik: HMD |
| Konferenzangaben | XVII IMEKO World Congress, Dubrovnik, 22-27, June, 2003, Croatia |
| Freie Schlagworte | Hardness scale definition ; national primary standards ; measurement uncertainty ; Working Group on Hardness of CCM |
| Zusammenfassung | 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. IMEKO) and international organizations for standardization (e. g. ISO and OIML), 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 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. It appears that the technical capabilities to reduce the uncertainty in the Rockwell C hardness scale, from about ±1 HRC to ±-0,2 HRC, is within the state of the art. Uncertainty evaluations taking into account the present state of the art of measurement capabilities show that, adopting improved metrological definitions of the HRC scale, the measurement uncertainty can significantly be reduced. Many of the effects, which influence Rockwell measurement results, also occur in Brinell and Vickers hardness tests being characteristics of the material; these effects must be combined with other peculiarities of the Brinell and Vickers hardness tests, such as the effect of the numerical aperture of the lens used for the optical measurement of the indentation. |
