Test: Corrosion resistance of 2205 duplex pipe under dynamic seawater friction

The seawater scouring friction and wear tester and electrochemical workstation were used to test the changes in the corrosion resistance of the duplex stainless steel pipe during seawater sliding wear.

Before the experimental test, the sample was immersed in artificial seawater for 10 minutes. After the static open circuit potential of the sample was stabilized, the seawater scouring friction and wear tester was turned on. The sliding time was 60 minutes. The friction and wear tester was stopped and the surface of the surface after sliding wear was tested Potential.

The open circuit potential of the wear surface of 2205 stainless steel tube in static and sliding wear changes: The open circuit potential under seawater static conditions is about -0.2V, and with increasing immersion time, the open circuit potential is more stable and has a slight increase trend, indicating that the With the increase of soaking time, the passivation film formed on the surface of 2205 stainless steel pipe is more stable and denser, thereby improving the corrosion resistance of duplex steel;

When sliding wear starts, the open-circuit potential decreases sharply to about -0.75, and as the applied load increases, the open-circuit potential decreases more. With sliding wear, the open-circuit potential becomes more stable and less than -0.8V, so 2205 The cathodic protection potential of the stainless steel tube was set to -0.8V. The results of the open circuit potential change showed that sliding wear damaged the passivation film on the surface of the 2205 stainless steel tube, which caused the open circuit potential to decrease sharply. And repair to a certain dynamic equilibrium, so that the open circuit potential maintains a stable value during the sliding process;

When the sliding wear stops, the open-circuit potential increases rapidly, and with the increase of the static soaking time, the open-circuit potential recovers to be stable, about -0.55 or less than -0.2 before sliding wear.

The above shows that the sliding wear of the 2205 duplex pipe changes the microstructure of the surface and reduces the open circuit potential of the wear surface.