Nickel Alloy clad tubulars are increasingly used for riser applications where concerns about
carbon steel integrity and life expectancy exist. Here galvanic corrosion is one of possible
problems.
The objective of this paper is to investigate the performance of corrosion inhibitor on the
galvanic corrosion of Nickel Alloy and Carbon steel X65. Multiphase flow loop tests were
conducted to evaluate the effect of incline angles, flowing conditions, and inhibitor performance
on possible detrimental influence of galvanic coupling between carbon steel and Nickel Alloy.
To determine the galvanic coupling effect, a series of pipe spool pieces made of Nickel Alloy
and carbon steel X65 were used into the multiphase flow loop. The sections were made such
that the interior exposed surface ratio was 10:1 (Nickel Alloy to X65 carbon steel). A
commercial corrosion inhibitor was evaluated.
Results showed that severe galvanic corrosion was observed on carbon steel pipe sections
coupled with Nickel Alloy in the absence of inhibitors. The galvanic corrosion attack was
significantly decreased on the carbon steel pipe sections with the presence of corrosion
inhibitor.
Key words: galvanic corrosion, multiphase flow loop, corrosion inhibitors