In order to analyse the microstructure and the layer structure of heat-treated components, a metallographic section is prepared. For this, the section of a component or test piece to be analysed is removed, embedded in epoxy resin and then sanded and polished. On such a section, the hardness-depth progressions of surface layer hardened components can then be determined by the Vickers process (CHD, NHD, SHD).

By etching the polished surface with special etching solutions, the microstructure of the material is made visible. In this way it is possible to assess the desired or undesired changes in the microstructure caused by heat treatment and also to identify and evaluate the layers created (for example the compound layer after nitriding) under the microscope.