Hydrogen induced internal cracking in metals caused by transient thermal processes

A quantitative model describing the behavior of cracks in metals filled with hydrogen gas is presented. Surplus filling of crack with hydrogen is caused by its diffusion flux due to transient thermal processes combined with internal heterogeneities in metals. The analysis of kinetics of hydrogen diffusion, precipitation into crack and its propagation is performed. The model may be employed to assessment of structural integrity under conditions of hydrogen destruction. An example of analysis of hydrogen induced delamination in weld-overlayed hydrotreating reactor pressure vessel is given.