Effect of Applied Stress on Corrosion and Mechanical Properties of Mild Steel

There is little knowledge on the effect of stress on corrosion of mild steel and how the combination of stress and corrosion affects the mechanical properties of mild steel. This paper presents a comprehensive experiment to provide evidence of the effect of stress on corrosion progress and mechanical properties of corroded steel. Test specimens, both stressed and nonstressed, were immersed in hydrochloride solutions with various acidities. Cause and effect relations among stress, corrosion, and mechanical properties of corroded steel are investigated and analyzed quantitatively at both macrostructural and microstructural levels. It is found that stress can accelerate the corrosion process and contribute to intergranular corrosion and intergranular stress corrosion cracking of steel. Consequently, stress can expedite the reduction of mechanical properties of corroded steel, especially the ultimate strength and failure strain. The significance of this paper is that it not only proves the effect of stress on corrosion and mechanical properties of corroded steel but also provides a more accurate understanding of cause-effect relationships among stress, corrosion, and mechanical properties of corroded steel.