Study on Similarity Low of Hardness Using Small Ball Rebound Test, eNM

Takashi Yamamoto, Masayuki Yamamoto, Mizuki Watanabe, Kensuke Miyahara
Abstract:
We investigated the law of similarity for hardness with respect to a newly-developed small ball rebound hardness test method. In the case of a spherical indenter hardness test such as that used for Brinell hardness, only if d/D were a constant, where D is the diameter of the indentation and is the diameter of the spherical indenter, would the indentations and the deformation regions caused by spherical indenters of different sizes have similar shapes, and therefore allow the same hardness values to be obtained. Using hardness blocks of 200 to 900 HV made of eutectoid carbon steel as specimens, as the measure of hardness we investigated the coefficients of restitution for 5, 3, and 2 mm alumina ceramic ball indenters with an impact velocity of 10 m/s. The test results were that the coefficients of restitution agreed well with the values of d/D for spherical indenters of different sizes, so we believe that this test method is a rebound hardness test method that satisfies the law of similarity for hardness, as is true for Vickers hardness.
Keywords:
law of similarity for hardness, rebound hardness, hardness reference block, coefficient of restitution
Download:
IMEKO-TC5-2017-007.pdf
DOI:
-
Event details
IMEKO TC:
TC5
Event name:
TC5 Conference 2017 - Measurement facing new challenges!
Title:

13th Conference on the Measurement of Hardness (together with 23rd TC3 Conference on the Measurement of Force, Mass and Torque and 4th TC22 Conference on Vibration Measurement)

Place:
Helsinki, FINLAND
Time:
30 May 2017 - 01 June 2017