Corrosion Behavior of 316L, 317L and 904L Stainless Steels in Acetic Acid Solution Containing Bromide Ion

Aiming at the corrosion problem of oxidation unit equipment of purified terephthalic acid (PTA) production unit in a factory, an immersion corrosion test was carried out in a high temperature and high pressure reactor. The effect of temperature on corrosion resistance of 316L, 317L and 904L stainless steels in acetic acid solution containing Br^- under aerobic and anaerobic conditions was investigated. Electrochemical characteristics and surface corrosion morphology of three materials were analyzed by electrochemical test, stereo microscope and scanning electron microscope. The results showed that with the increase of temperature, the corrosion rates of the three materials increased gradually, and their corrosion rates under aerobic condition was higher than those under anaerobic condition. The corrosion resistance of the three materials was 904L stainless steel, 317L stainless steel and 316L stainless steel in order from high to low. When the temperature was 60℃, the corrosion degree of three materials was relatively light, and their surface maintained metallic luster without obvious corrosion marks. As the temperature continued to rise, the corrosion degree of the material surface was aggravated. When the temperature was lower than 60℃, pitting corrosion occurred in all three materials, and their pitting corrosion potentials was 316L stainless steel, 317L stainless steel and 904L stainless steel in order from low to higt.