Erosion-corrosion behavior of 2205 duplex stainless steel in wet gas environments

•Study the effect of pure relative humidity of gas environment.•Determination of synergistic effect of relative humidity and gas flushing on 2205 duplex stainless steels.•Determination of critical value of gas velocity for corrosion of 2205 duplex stainless steels.

An unsteady state thin electrolyte film in the acidic environment of a natural gas pipeline was simulated using a self-assembled impingement jet system to study the corrosion behavior of 2205 duplex stainless steel (DSS) in gaseous environments with different relative humidity values. The electrochemical properties and surface morphologies of 2205 DSS samples were analyzed. Corrosion did not occur on the surface of 2205 DSS under wet conditions without gas impingement, whereas it did occur under the same conditions in the presence of gas flushing. The effect of gas-flow velocity was investigated with the help of computational fluid dynamics simulation. The results showed that the corrosion rate increased with accelerating flushing velocity in an environment with 80% relative humidity, particularly when the flow velocity was higher than 14 m/s. In addition, the sizes and number of pits increased remarkably at flow velocities higher than 14 m/s.