Effect of applied stress on corrosion and mechanical properties of mild steel

There is little knowledge on the effect of stress on corrosion rate of mild steel and as to how the combined effect 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 non-stressed, are immersed in hydrochloride acid with acidity ranging from 0.00001 Molar to 3 Molar. Cause and effect relations among stress, corrosion and mechanical properties of corroded steel are investigated and analysed quantitatively at both macrostructural and microstructural levels. It is found in the paper that the stress can accelerate the corrosion progress and contribute to the 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.