“…The measured maximum thicknesses of the decarburized layers after different annealing times are: Complete decarburization of 160 µm, including 80 µm of ferrite layer (t a = 1 2 h); complete decarburization is equal to the 3 µm thick ferrite layer (t a = 1 h); and complete decarburization of 280 µm, including the 70 µm of ferrite layer (t a = 2 h). The largest anomalies regarding the visible decarburization are found in this temperature range (the characteristic coarse-grained ferrite surface layer is the thickest after t a = 1 2 h, the decarburization is practically not visible after t a = 1 h, a large part of the surface is left non-decarburized even after t a = 2 h, and constant thicknesses of the partially decarburized layer are not observed; the results are therefore different to those in, e.g., [9]), but they can be explained by the kinetics of oxidation and decarburization and with different fitting of the oxide, which affects the kinetics of these processes. As mentioned before, in general, there is a tightly fitting oxide layer present on the surface of the samples after cooling, especially on the parts that were not decarburized, showing the effect of fitting of the oxide layer on the decarburization of the steel.…”