The paper describes the metallographic analysis of a metal part from the cupola construction in the Main Railway Station in Pilsen. The station in the Art Nouveau style was completed in 1907. The part was screwed to a vertical column and used as a pulley, probably for the transport of other parts. The cross-section consisted of visible bands. The microstructure was heterogeneous, formed by connected individual bands, ferritic structure predominated, but in some bands it was ferritic - pearlitic. The structure contained both minor inclusions and complex elongated inclusions consisting of grains and binder - their composition was determined by ED microanalysis. The analysis showed that it is a wrought (puddled) iron with a considerable amount of slag, which was produced with technology used in the 19th century. However, at the beginning of the 20th century, modern steel production methods were used for profiles and thus it is unclear whether this screwed part for manipulation represents the whole construction.

As part of the project “Thermostat for universal use in (electro) mobility”, an analysis of three currently used thermostats failed during operation was performed. In all three cases, cracks occurred in the brass outer casings. The cracks were open and fractographical observation was performed. The microstructure of the material was evaluated using both the light and scanning electron microscopy. The local composition of the material was determined by EDS microanalysis. Furthermore, hardness profiles were measured. The cracks were predominantly intergranular with a smaller portion of transgranular cleavage. The microstructure was formed by a mixture of α- and β-phase grains and lead particles. In addition to the stress caused by the overpressure of the molten wax, a higher level of residual stresses caused by deformations can be expected. The failure was caused by the mechanism of stress-corrosion cracking. Metal induced embrittlement or/and corrosion fatigue could interact too.