Hot Corrosion Behavior of 12Cr1MoV Steel in High Temperature Mixed Alkali Chloride Salt

Hot corrosion behavior of 12Cr1MoV low alloy steel in mixed salts of 70%NaCl-30%KCl, 50%NaCl-50%KCl, 30%NaCl-70%KCl (mass fraction) at 600 ℃ and 700 ℃ was studied by the corrosion kinetic method, respectively. The corrosion morphology at the surface and cross section was observed, the composition of the corrosion products was analyzed and the corrosion mechanism was investigated. The results show that the 12Cr1MoV steel was corroded seriously at the surface and in the substrate in the high temperature mixed salts. The produced Cl₂ inside the steel was the main reason for the initiation and propagation of defect structure such as cracks and pores. With the increase of KCl content in mixed salts and of the temperature, the corrosion rate of sample increased rapidly. The corrosion mode in the substrate changed from intergranular corrosion to integral corrosion due to the relatively high content of KCl.