Corrosion Mechanism for Q235 Steel Tube Wall in Outer Tube Gallery of an Oil Company

Static coupon testing for different times was carried out for Q235 carbon steel in the atmospheric corrosion environment of outer tube gallery of an oil company. Q235 carbon steel tubes on site were sampled. The corrosion products on the surface of Q235 carbon steel were analyzed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The results show that the element Fe existed as γ-FeOOH and α-Fe₂O₃ in corrosion products after long-time corrosion, SO₂ in atmosphere worked as catalyst in corrosion process.