A Comparative Study of the Corrosion Behavior of 30CrMnSiNi2A in Artificial Seawater and Salt Spray Environments

Abstract

In this work, the corrosion behavior of 30CrMnSiNi2A in a simulated marine environment was studied. The electrochemical behavior was studied by changing the temperature and pH of the solution environment. Detailed information about the rust layer was obtained by scanning electron microscopy, energy-dispersive spectroscopy, and X-ray diffraction. The stress corrosion cracking (SCC) behavior of the steel in artificial seawater was studied through a slow strain rate tensile test (SSRT). The experimental results showed that the corrosion products were mainly composed of α-FeOOH, γ-FeOOH, and Fe3O4, while the content of Fe3O4 in the rust layer formed in the salt spray environment was much higher. The steel in the salt spray test showed a much higher corrosion rate than that observed when it underwent a full-immersion test. The decrease in the pH value mainly accelerated the cathodic reaction, and the temperature simultaneously promoted anodic dissolution and cathodic reductions. The decrease in the elongation during SCC test was minimal, while the index for the reduction-in-area showed a slight SCC susceptibility in the seawater environment, suggesting that anodic dissolution is the dominant mechanism of SCC degradation.