Developing prepitting procedure for near neutral pH stress corrosion crack initiation studies on X-52 pipeline steel

Abstract

In this paper, a procedure for prepitting of pipeline X-52 steel in the bicarbonate/carbonate solution was developed. Sodium chloride was added to the solution to induce pitting, and the optimum concentration of chloride ions, which produced a low density of pits, was found. The procedure briefly included prepassivation of the steel in the solution with optimum concentration of chloride ions and then increasing the potential above the pitting potential to generate pits. The potential was then stepped back well below the pitting potential to grow the pits to the desirable depth. This procedure can be used to generate pits on tensile specimens, which can be subsequently employed in near neutral pH stress corrosion crack initiation studies. This can result in shorter duration of crack initiation experiments under real loading condition.

Keywords:

• Prepitting
• Pitting potential
• Near neutral pH SCC
• Crack initiation