Tribocorrosion Influenced Pitting of a Duplex Stainless Steel

Abstract

Due to its accelerated, uncontrollable, and unpredictable nature, pitting is one of the most common failure modes in pipelines used for oil and gas exploration. A comprehensive understanding of the mechanisms of pitting under conditions involving both abrasion and corrosion is currently lacking. This research investigated the effects of mechanical rubbing on the development of pitting of a widely used Type 2205 duplex stainless steel. Tribocorrosion experiments were conducted under mildly abrasive conditions where there is pitting but no significant material loss. Results showed that passivation was accelerated by rubbing, even though pitting was simultaneously formed. The length-to-width aspect ratio of the pits increased exponentially when the normal load during corrosive wear tests was increased. This phenomenon could lead to catastrophic failure in industrial applications such as underground and deep ocean pipes in the oil and gas industry.

Keywords

• abrasion
• corrosion-wear
• pitting
• duplex stainless steel
• mechano-electrochemistry