Mechanical and Microstructural Evaluation of Corrosion and Hydrogen-Induced Degradation of Steel

Mild steel is one of the most commonly used materials in the construction industry throughout the world, but it is also very vulnerable to corrosion in aggressive environments. There is little research on how corrosion and the hydrogen released from the corrosion process affect the mechanical properties of the corroded steel. The intention of this paper is to present results produced from a comprehensive experimental program designed to investigate the effects of corrosion and corresponding hydrogen on the degradation of mechanical properties of mild steel in corrosive soil environments. Both microstructural analysis and mechanical tests on corroded steel are undertaken at different exposure times and conditions of corrosion. The effects of corrosion and the released hydrogen on steel are examined phenomenologically and analyzed quantitatively at the microstructural level in terms of constituent elements and phase changes, and at the macrostructural level in terms of mechanical properties of strength and ductility. From the analysis of test results, a relationship of cause and effect of corrosion, hydrogen release, and strength reduction is established. The results and their analysis presented in the paper can contribute to the body of knowledge related to the degradation of mild steel, which helps in determining its service life prediction under corrosive environments.