Study on the Corrosion Behavior of New Type of Acid Resistant Steel in Sulfuric Acid Containing Environment

Abstract

In order to study the corrosion resistance and mechanism of a new type of acid resistant steel (LGNS-P) in sulfuric acid containing environments, Q345B carbon steel was used as a comparative material, and the corrosion behavior of two types of steels before and after the full immersion test was observed and tested through sulfuric acid accelerated corrosion test, corrosion weight loss analysis, SEM observation of corrosion morphology, and electrochemical potentiodynamic polarization tests. Results showed that the corrosion degree of LGNS-P was obviously less than Q345B, and the corrosion rate was gradually decreased during the test cycles. By contrast, the corrosion rate of Q345B increased first and then decreased, reaching its maximum after 240 h of testing. Compared to Q345B, the corrosion product layer of LGNS-P was more uniform and denser, which blocked the direct contact between corrosive ions and the substrate to some extent. In addition, there were some Fe oxides on the surface of both steels, but Sb oxides were also found on the surface of LGNS-P, which had certain acid resistance and could enhance the bonding ability of the corrosion product layer and the substrate. Overall, the above differences caused the significant improvement of acid corrosion resistance of LGNS-P

Keywords

• lgns-p acid resistant steel|sulphuric acid dew point corrosion|full immersion|corrosion products|acid corrosion resistance