Influence of electrochemical hydrogen charging on loss of plasticity and development of volumetric microdamaging of 60S2A steel

Medium-carbon 60S2A steel is sensitive to electrochemical hydrogen charging in aqueous solutions at room temperature, which leads to a significant loss of the material plastic characteristics. According to the results of uniaxial tensile mechanical tests of cylindrical specimens, the relative elongation and relative area reduction decreased approximately three times when the concentration of hydrogen in steel changed in the range of 0.3–5.0 ppm. Under the impact load, the development of volumetric microdamage of 60S2A steel was observed only when hydrogen-charged in the solutions with pH = 1 and lower. The critical parameter of the material state is the energy E of the impact load under three-point bending of smooth beam specimens, the decrease of which indicates an increase in the intensity of the hydrogen-induced damage. The existence of correlation dependence between the parameter E and the value of the concentration of residual (trapped) hydrogen C_H in the metal is shown. The obtained results can be used to develop technological processes to increase the fragmentation of structural medium-carbon steels.