Localized Destruction Criterion before the Onset of High-Temperature Hydrogen Corrosion of a Hollow Steel Cylinder

The article describes the processes that have a decisive effect on the initiation of corrosion cracks: accumulation of methane concentration, evolution of porosity, and the thermal state of methane in micropores. An initial boundary value problem is formulated, where the methane concentration is considered in the diffusion equation instead of hydrogen concentration. An approximate solution to the diffusion equation is obtained. A plane deformation with cylindrical micropores around which local stresses arise is considered. It is suggested that the initiation of corrosion cracks occurs when the sum of the circumferential stress under the effect of hydrogen pressure inside the cylinder cavity and the circumferential local stress under the effect of methane pressure inside the micropore reaches the short-term strength limit.