Dependence of the abnormal protective property on the corrosion product film formed on H2S-adjacent API-X52 pipeline steel

The dependence of the protective property on the corrosion product film formed on API-X52 pipeline steel was investigated using the electro-chemical hydrogen permeation method in acidic solution under various H2S partial pressures. The hydrogen permeation current is dependent on the H2S concentration and the corrosion product film. The hydrogen permeation current increases with the H2S partial pressure, and decreases with thickening the corrosion product film. The dense corrosion product films formed in 1.0 MPa H2S shows the obvious protective property against hydrogen permeation, while the delamination of the corrosion product film formed in 0.1 MPa H2S weakens the protective property. The hydrogen permeation current in 1.0 MPa H2S is lower than that in 0.1 MPa H2S after 200 h immersion in acidic solution and this is of great significance to the service life prediction and the prevention of hydrogen embrittlement in H2S-adjacent pipelines.