Hardness change part detection device, hardness change part detection method and program

摘要

PROBLEM TO BE SOLVED: To provide a hardness change portion detecting device, a hardness change portion detecting method and a program capable of detecting a change in hardness of a surface layer of a steel material with higher accuracy. A hardness change unit detecting device (1) includes a measuring unit (10) for measuring parameters that change depending on the properties of the surface layer of at least two types of steel materials at a plurality of measurement positions with respect to the surface layer of the steel material (101) to be measured. A determination unit 20 for comparing the measurement result of the measurement unit 10 with the reference value and the determination table to determine whether or not the portion is a hardness change portion is provided, and the reference value is for a steel material having the same hardness as the hardness change portion. It is a measured parameter, and the judgment table shows that with respect to the change in stress, both tend to have the same tendency that matches either the increasing tendency or the decreasing tendency, and one of the opposite tendencies that are different from each other in the increasing tendency and the decreasing tendency. , It is a table showing the increase / decrease in hardness created based on two types of parameters that have either a reverse tendency different from a change in stress or a tendency having the same tendency with respect to a change in hardness. [Selection diagram] Fig. 1