Definition of Loading for Hardness Blocks

摘要

In a previous report, the authors investigated changes in hardness measurements when load rise time (LRT) was changed over a broad range in Vickers harness tests with loads of between 15 kgf and 150 kgf. As a result, we reported that hardness measurements varied according to the LRT value for every test load, while they remained almost constant between 15 kgf to 150 kgf if LRT was the same, although the indention velocity of the indenter differed by more than three times between the two loads. It is very interesting that the considerable difference in indentation velocity due to varied test loads was not reflected much in hardness measurements. We, therefore, verified the effects of loading speed on hardness measurements theoretically from the strain rates of indentation deformation under the indenter and obtained some findings as follows.