Determination of hardness and hardness penetration depth of metal components by Non Linear Harmonics Analysis
Dieter Stegemann, Wilfried Reimche, K. L. Feiste, Ch. Reichert, P. Marques-Fetter · AIP conference proceedings · 1999
For the characterization of steel quality, hardness is a very important parameter. The magneto-inductive Non Linear Harmonics Analysis (NLHA) has been developed and used as a non destructive technique for measuring core hardness, surface hardness and hardness penetration depth of steel components. A description of the working principle of NLHA is given together with the setup of a typical hardness measuring system. Examples are given for the determination of carbon content in steel foils, measurement of core hardness in gear bolts where the hardness was controlled by tempering. Further results demonstrate measurements of core hardness, surface hardness and hardness penetration depth of nitration hardened steel samples. The final example shows a hardness profile of a case hardened shaft.