Effect of penetration of corrosion on the load- bearing capacity of mild steel

Abstract

The field of Metallurgical Engineering associated with the service life of corroded metallic structures has been studied in extensive detail, the world over. Most of the theses in this area have focused only on the general attack (uniform corrosion) on steel structures in a range of atmospheres. This study sought to examine whether the penetration of corrosion beyond the general attack into the bulk material, has a significant effect on the load-bearing capacity of mild steel structures. Mild steel samples were corroded in an aggressive atmosphere over a 5-month period, subjected to periodic tensile testing and corrosion mass-loss analyses, and examined under optical and electron microscopy. Through the identification and measurement of the penetration of corrosion using scanning electron microscopy, this research managed to correlate corrosion mass-loss and tensile load-loss data with said microscopic measurements. The results showed that the actual breaking loads deviated negatively from the expected loadbearing capacity, which was determined through conventional methods. This deviation showed a close correlation to the increase of penetration of corrosion with time.