Insight to atmosphere corrosion behavior of Q345NH steel in Wenchang tropical marine environment

Abstract

The atmospheric corrosion behavior of Q345NH steel exposed to various coastal distances was investigated in Wenchang, China. The results revealed that with the shortening of the distance from the coast, the amount of chloride ion precipitation increased and the corrosion rate accelerated. After exposure at different locations, the surface conditions and microstructure are widely divergent owing to their unique composition and phase distribution of the rust layer. The high Cl− concentration along the coast promoted the synthesis of β-FeOOH, which favored the synthesis of Fe3O4 in humid environments. Due to the disparity in molar volumes of these phases, the transformation process led to the crack and deterioration of the rust layer.

Keywords

• Atmospheric corrosion
• Q345NH steel
• Distance from the coast
• Phase distribution
• Cl− concentration