ABSTRACT
ABSTRACT In civil engineering projects, mild steel is commonly used in many infrastructure including buried pipes due to its unique mechanical behaviour. The life cycle of a steel structure can adversely be affected by corrosion attack and hydrogen-induced embrittlement when exposed to various environmental conditions. Hydrogen embrittlement (HE) is a form of deterioration which can be associated to corrosion and corrosion-control processes. Several researchers have reported the damaging effect of hydrogen on the ductility of steel structures. However, there is a difference of opinion among researchers about its effect on the yield and failure strength which are the key parameters for the life cycle design of any steel structure. The current research aims to quantify the degradation of mechanical properties of mild steel subjected to HE in various simulated environments using laboratory-controlled experiments. Mild steel specimens are immersed in various simulated corrosive environments of hydrochloric acid and soil solutions. For each corrosive environment, nine specimens for tensile strength and three specimens for hydrogen measurements are tested at three time periods (7, 14 and 28 days). From the experimental findings, loss of mechanical properties (yield and ultimate strength) and ductility are observed. Various characterization techniques such as SEM, and optical microscope are used to provide the solid reasoning of HE effect on the durability of mild steel. This paper presents qualitative and quantitative explanations of hydrogen-induced damage on structures and materials made up of mild steel. The results from the current study can be used to relate hydrogen concentration and time-dependent corrosion for accurate prediction of the safe life of various steel structures.
