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Deep cryogenic heat treatment is a finishing process applied to the vast variety of materials and more specifically on steels. In this investigation the effect of the deep cryogenic heat treatment on the microstructure, corrosion behaviour and corrosive- wear behaviour of the carburised 16MnCr5 steel was studied. Results show that the deep cryogenic heat treatment eliminates the retained austenite as well as increasing the carbide percentage. These phenomena increases the wear rate of the samples as well as declining the corrosion rate of the deep cryogenically treated samples (DCT) due to decreasing the dissolved chromium atoms in the structure. Moreover it was clarified that the effect of corrosive environment during the wear test is more significant on the DCT samples as compared with the conventionally treated ones (CHT). [ABSTRACT FROM AUTHOR]

Deep cryogenic heat treatment is a supplementary process performed on steels specifically tool steels before tempering to improve the wear resistance and hardness of these materials. The carbide distribution changes via the electric current flow or the application of a magnetic field during the deep cryogenic heat treatment. Hence, the electric current and the magnetic field were applied to the samples to investigate the corrosion behavior of the deep cryogenically treated samples by electrochemical impedance spectroscopy and potentiodynamic polarization measurements. The results showed that increasing the carbide percentage and achieving a more homogenous carbide distribution during the deep cryogenic heat treatment will remarkably decrease the corrosion resistance due to a decrease in the solutionized chromium atoms in the structure as well as the increase in the martensite-carbide grain boundaries (the galvanic cell areas). Moreover, it was clarified that the electric current flow and magnetic fields reduce the carbide percentage, which leads to an increase in the corrosion resistance of these samples in comparison with the deep cryogenically treated samples. [ABSTRACT FROM AUTHOR]