A Consideration on the measurement of Hardness
Rinpei Kikuti · Journal of the Japan Institute of Metals and Materials · 1943
Hardness is, in the industrial world, used merly to show quantitatively the solidity of an object and therefore no absoluteness lies in it. Consequently, it is the numerical value which, is shown only when all the conditions are satisfactorily completed. It changes most especially by the load, decreasing gradually as the load becomes smaller, but-(1) By seeking the relation between the load and hardness, the singularity of hardening can be explained from the difference in “Hardness curves”, though it has hitherto shown the same value in the measurement of hardness under the fixed load. (2) By measuring hardness tinder the small load, very small changes, that have never been found out before, can be recognized in the structure after tempering. By this phenomenon that could be recognized for the first time under the small load, we learn that by hardness also the study of structure which has not been obtained hitherto can be deepened. This is the reason why the writer adovocates the use of the words “Hardness analysis”.