Effect of corrosion and hydrogen embrittlement on microstructure and mechanical properties of mild steel

This paper investigates the effect of corrosion on degradation of mechanical properties of G250 mild steel. Corrosion tests are conducted by immersing steel into hydrochloride acid solutions, with acidity ranging from 0.00001 M to 3 M. Both macro analysis and micro analysis are undertaken to investigate the mechanism of corrosion induced degradation of mechanical properties. Intergranular corrosion is found for mild steel during corrosion. Results indicate that there is considerable reduction in mechanical properties due to corrosion, which is attributed to a combined effect of hydrogen embrittlement, changes in element composition, grain size and phase composition, and the residual stress concentration at corrosion pits.