USE OF SEVERAL IMPACT PARAMETERS AT TESTING OF COMPLIANT AND ROUGH METALLIC ARTICLES BY THE DYNAMIC INDENTATION METHOD
Dynamic hardness meters are widely used in different branches of industry at present time. Dynamic devices are portable, easy to operate, accurate, allow to test large articles. A principle of operation of dynamic hardness meters is based on applying impact of small energy with indenter against the...
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Veröffentlicht in: | E-journal of Nondestructive Testing 2008-02, Vol.13 (2) |
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Hauptverfasser: | , , , , |
Format: | Artikel |
Sprache: | eng |
Online-Zugang: | Volltext |
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Zusammenfassung: | Dynamic hardness meters are widely used in different branches of industry at present time. Dynamic devices are portable, easy to operate, accurate, allow to test large articles. A principle of operation of dynamic hardness meters is based on applying impact of small energy with indenter against the material under test. The indenter has high value of hardness and during the process of its intrusion into article causes elasto-plastic deformation of metal. At the active stage of impact indenter moves with reducing of its speed into metal of a part under test. After a stop indenter begins moving outside under the action of indentation elasticity forces (passive stage of impact). A difference between indenter kinetic energies before and after the impact corresponds with the plastic deformation energy losses. Purchasable dynamic testers register impact and rebound velocity or only rebound velocity. A velocity restitution coefficient, which is calculated as a ratio of rebound to impact velocities, is a measure of article hardness (Shore hardness). A presence of stable relationship between static hardness of metals (Brinell, Rockwell) and velocity restitution coefficient allows to calibrate dynamic hardness meters directly in static hardness units. |
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ISSN: | 1435-4934 1435-4934 |