Effect of surface conditions on electrochemical and mechanical properties of pipeline steels in near-neutral pH environment

This research focused on the effect of surface conditions on electrochemical and mechanical properties of pipeline steels in near-neutral pH soil environment. These conditions included surface roughness, surface scratch orientation, and surface deposits arisen from the reaction between cathodic current and soil electrolytes. The electrochemical response of steels in various surface conditions was investigated by using the traditional electrochemical technologies. Davanathan electrochemical hydrogen charging system was used to study the hydrogen permeation behaviors of pipeline steel under the influence of surface variables. LECO Hydrogen Determinator was used to measure the total hydrogen content in the samples exposed to various chemical and electrochemical conditions. The standard slow strain rate tensile testing was conducted to understand the combined effect of corrosion and hydrogen on the mechanical properties of the pipeline steel. The mechanisms governing the synergistic interactions among near-neutral pH environment, dynamic loading and material variables at the surface were also discussed.