Corrosion behavior of carbon steels Q235 and Q450 in dry hot atmosphere at turpan district for four years

Atmospheric exposure of carbon steels Q235 and Q450 were conducted for 4 a in dry hot atmospheric environment at Turpan district of Xinjiang Uygur Autonomous Region. The results showed that the surface of the two steels presented obvious corrosion products scale. The average corrosion rate of Q450 and Q235 was 12 and 14 g·m^-2·a^-1 respectively. Thus, Q450 steel exhibits corrosion rate lower than Q235 steel, and while the corresponding corrosion pits were relatively shallow. The corrosion products of the two steels composed mainly of α-FeOOH, γ-FeOOH and Fe₂O₃·H₂O, while the proportion of α-FeOOH for Q450 was higher than that for Q235. The corrosion products on Q450 were relatively dense. Thereby, it hindered the absorption of water and sediment, leading to the decrease of corrosion rate. The result of EIS demonstrated that the resistance of corrosion products and surface charge transfer of Q450 was greater than that of Q235, i.e. the corrosion products of Q450 had better protectiveness.