Effect of the Flow Velocity on the Corrosion Behavior of UNS S41426 Stainless Steel in the Extremely Aggressive Oilfield Environment for the Tarim Area

Effect of flow velocity on the passive film and pitting corrosion behavior of UNS S41426 stainless steel (SS) under the extreme oilfield environment was investigated using different techniques such as microscopy, nanoindentation, and electrochemical techniques. The experimental results show that the corrosion rate of UNS S41426 SS increased with velocity. The increase in flow velocity decreased the thickness and content of amorphous Cr(OH)₃ (s) in the film. This in turn increased the density of phase boundary, resulting in a higher defect density. Thus, the UNS S41426 SS film became susceptible to breaking. Furthermore, the pitting had a higher susceptibility to grow to a larger size both in the vertical and horizontal directions with the increase in flow velocity.