Determination of hardness and hardness penetration depth of metal components by non linear harmonics analysis

摘要

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 o a typical hardness measuring system. Examples are given for he determination of carbon content in steel foils, measurement of core hardness in gear bots where the hardness was controlled by tempering. Futhrer 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 bardened shaft.