THE I NFLUENCE OF THE TIME EXTENSION ON THE PRELIMINARY TEST FORCE IN ROCKWELL HARDNESS MEASUREMENTS

In the light of the ISO 6508 revision, under t he ISO TC 164 Technical Committee on Mechanical Testing of Metals, a study on the influence of the extended duration of the preliminary test force was taken, which in some cases a longer time could be required. Several HRC tests were performed with different conditions of time and materials by using the Hardness Standardisation Machine of INMETRO/Brazil.