W muzeach przyrodniczych możemy zobaczyć repliki wymarłych przed wiekami zwierząt. Na czym polega sztuka ich „ożywiania”? Jak się je rekonstruowało kiedyś i jak to się robi dzisiaj?

Visitors to natural history museums can admire replicas of animals that died out ages ago. What tricks can be used to “bring them to life”? How have such animals been reconstructed in the past, and how is it done today?

Deep cryogenic treatment (DCT) is gaining popularity as a treatment used to modify structures obtained during heat or thermo-chemical treatment. The article presents the influence of DCT, carried out during heat treatment before and after gas nitriding processes, on the formation of gas nitrided layers on X153CrMoV12 steel. It was found that the use of DCT between quenching and tempering performed prior to gas nitriding processes, increases the hardness, thickness and wear resistance of the nitrided layers. At the same time, if we apply cryogenic treatment during post-heat treatment of nitrided layers, we also get very high wear resistance and increased thickness of nitrided layers, in comparison with conventional gas nitriding of X153CrMoV12 steel. In this case, DCT significantly increases also the hardness of the core by the transformation of retained austenite and the precipitation of fine carbides of alloying elements.