According to the new definition of Rockwell hardness given by the international working group on hardness, the Rockwell hardness primary standard machine has been upgraded. As the new loading system, loading monitor system, PLC control system and laser measuring system have been developed, the function of the new primary standard machine can now meet the requirements of the new definition and its measuring uncertainty can reach the expected values.

The effect of time-related parameters such as loading velocity, load application time, and gauge reading time on Rockwell hardness measurement was investigated for polymers such as polyethylene (PE), polypropylene (PP), polyvinylchloride (PVC) and acrylic plate. It was found that keeping the specific requirements of the test procedure, especially for the time parameter related one, is very important to obtain reliable and repeatable data in polymer hardness measurement. These characteristics of plastic hardness measurement are because of the good elastic properties of polymers and showed continuous deformation even at the time of data reading. The optimum condition for hardness measurement appeared to be 4 s for load application time, 15 s for test load application net time, and 15 s for gauge reading time after unloading. After this preliminary test for establishing protocol, a round robin test was carried out for six laboratories and it appeared that the testing machine should be one in which time-related variables are controllable. In other words, hardness tester with a function of plastic mode test showed much better repeatability in measurement data because of the automatic reading of data at a specific time. Verification of hardness tester using brass reference block was not enough to guarantee the reliability test results or reduced data scattering for polymer.

Evaluation of measurement uncertainty when correction value in ISO 6508 and ASTM E18 is applied is disputable. Using corrections, discrete and without uncertainty, is a difficulty to provide best measurement capability related to the application using the corrections. In order to study the possibility to complete the corrections to be in term of equations together with uncertainty of the equation, cylindrical shafts at nominal hardness 20 HRC, 40 HRC, and 60 HRC with diameter 6 mm to 38 mm were supplied in this experiment. In addition, this study includes the accuracy of the corrections by considering the effect of frame deformation of flat anvil and v anvil, effect of misalignment between indenter and cylindrical shaft, as well as effect from indenters. The corrections in form of equations for nominal hardness 20 HRC, 40, HRC, and 60 HRC along with uncertainty less than ±0.25 HRC are reported. This confirms the possibility to revise the corrections with uncertainty for convex cylindrical surfaces in ISO 6508 and ASTM E18.

The Vickers hardness test can cover an extensive range of test loads from several gram-force (gf) to 100 kilogram-force (kgf) with a single hardness scale. It is one of the most reliable strength tests because the simplicity of the testing theory and the indenter shape minimizes variances among hardness values obtained. The most vulnerable aspect of the Vickers method is an error when measuring the diagonal length of an indentation. In particular, an inexperienced operator tends to obtain smaller measurements than the actual length of the indentation. According to research by the authors, it is also revealed that the contrast of the microscopic image of an indentation varies with the angle of aperture of the objective lens. This report presents the results of an experiment on how measurer, measuring method, and aperture of objective lens (i.e., numerical aperture: N.A.) affect measurement of a Vickers indentation.

The effect of environmental vibration on Vickers hardness machine is reported in this paper. Test force 9.807 N (HV1) and 98.07 N (HV10), representing low-force hardness test and normal hardness test, were selected for this experiment. Two machines with different loading mechanism made indentation under influence of single sinusoidal vibration with frequency ranging from 10 Hz to 100 Hz and amplitude ranging from 0.002 m/s² to 0.04 m/s². Indentations were captured by CCD camera and diagonal lengths were measured automatically by software. Response to vibration for each loading mechanism, hardness level, and test force level is discussed in this paper. This experiment shows that the relative errors are higher than maximum permissible error in ISO 6507-2 when vibration amplitude higher than 0.005 m/s² or 0.0005 g_n. Result from this paper can be used as a guideline to revise maximum allowable vibration acceleration and test force scale to which the limit should be applied.