Effects of Sulfur-Containing Crude Oil on Top-of-Line Corrosion Behavior of 16Mn Pipeline Steel

The corrosion environment at the top of oil pipeline was simulated by a sulfur-containing crude oil corrosion test chamber, and the top-of-line corrosion behavior of 16Mn pipeline steel was studied in the sulfur-containing crude oil under different conditions of temperature and time. Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) were used to observe the corrosion morphology of the 16Mn pipeline steel and to analyze the composition of the corrosion product film on the steel surface. The corrosion rate of the 16Mn pipeline steel sample was calculated by weight loss method. The results show that the corrosion rate of the 16Mn pipeline steel increased with the increase of temperature of sulfur-containing crude oil. When the temperature was over 60℃, the corrosion product film formed, which can block the contact between steel base and corrosive medium and then slow down the corrosion process, so the corrosion rate stopped rising with a tendency of slow decline. At the same corrosion temperature, the initial corrosion rate was fast. As the corrosion time prolonged, a dense corrosion product film gradually formed on the surface of 16Mn pipeline steel, which was beneficial to suppress the top-of-line corrosion process and gradually reduced the corrosion rate.