Uncertainty Evaluation for Martens Hardness. Analysis of the Velocity Effect

The effect of indentation velocity is well known as one of the most significant parameters in hardness measurement. Tests accurately done using a primary hardness machine have shown effects larger than expected, however compatible with the differences evidenced with international comparisons, therefore acceptable in principle. This paper presents the measurement procedure adopted and the results obtained, with the invitation to other researchers to test velocity effect with different apparatus, to evidence, with independent measurement, the confirmation or rejection of obtained results and to help in finding an explication for this strong effect