Study on corrosion behavior of typical carbon steel and low alloy steel in deep sea of different sea areas

Abstract In order to meet the development needs of deep-sea oil and gas resources, deep-sea corrosion coupon tests were carried out in the South China Sea, the Western Pacific Ocean, and the Indian Ocean, which can provide a strong guarantee for the rationality of material selection of oil and gas pipelines, platforms and other facilities. In-depth studies were conducted on the environmental adaptability of typical carbon steel and low alloy steel materials after exposure for one year in the deep-sea environment of different sea areas. The main environmental factors affecting deep-sea corrosion behavior were also collected and analyzed. The results showed that the corrosion morphology of carbon steel and low alloy steel in deep sea environment was more uniform than that in the shallow seawater. With the increase of seawater depth, the evolution law of their corrosion rates in different sea areas was similar, with an obvious decline of corrosion rate in the beginning. The gray correlation results indicated that it was mainly controlled by temperature and dissolved oxygen. The high hydrostatic pressure had limited effect on accelerating the deep sea corrosion rate of carbon steel and low alloy steel, but it promoted the formation of more uniform corrosion morphology.