Hydrostatic pressure effects on corrosion behaviour of X80 steel in artificial sea water
Chengcheng Xu, Yuxiang Zhu, Wanlei Liu, Feihu Bao, Erju Liu, Feifei Huang, Lei Wen, Ying Jin, Dongbai Sun
Abstract
The effect of hydrostatic pressure (HP) on the corrosion behaviour of X80 steel is investigated to assist the development of deep-sea oil and gas resources. The results show that the corrosion current increases as HP increases whereas the charge transfer resistance follows the opposite trend. The corrosion products are composed of γ-FeOOH, α-Fe2O3 and α-FeOOH at atmospheric pressure, while Fe3O4 is only formed at a high HP. Additionally, the inner layer of the corrosion products contains more Fe3O4 compared with the surface corrosion layer. HP accelerates the corrosion rate of X80 steel due to its effect on the chemical and physical properties of the corrosion products, including the promoted reduction of γ-FeOOH and the formation of wider and deeper cracks on the corrosion product layer.