Corrosion-Mechanical Properties of Materials for Reactor Vessels

We established that, in the course of electrolytic hydrogenation, an aqueous medium of boron regulation with pH 8 significantly accelerates the growth of fatigue cracks in 15Kh2MFA and 15Kh2NMFA hull steels, especially in the metal of welded joints, as a result of hydrogen embrittlement at the tip of a crack. An increase in the strength of steels by means of heat treatment, a decrease in the frequency of alternating loading, and an increase in the stress ratio significantly accelerate the growth of fatigue cracks. We discovered the strongest influence of hydrogenation in the near-threshold region for low values of the stress intensity factor. The tendency toward passivation and the anticorrosive properties of 15Kh2MFA steel (i _cor = 5 mA/m²) are higher than those of 15Kh2NMFA steel (i _cor = 20 mA/m²), which can be explained by the higher inhomogeneity of the structure of the latter. The metal of welded joints has the lowest cyclic corrosion crack resistance and the highest tendency toward hydrogen embrittlement under conditions of stable or transient modes.