Corrosion Behavior of Super High Strength Steel FG20 in High-Sulfur Oilfield Water with Different pH Values

Electrochemical corrosion and indoor coupon corrosion experiments were used to study the corrosion behavior of super high strength steel FG20 for sucker rods in high-sulfur oilfield water with different pH values. The results show that with the increase of pH value of the oilfield water, the free corrosion potential, free corrosion current density and corrosion rate of the FG20 steel decreased. With the increase of pH value of the oilfield water, the corrosion products on the surface of the FG20 steel changed from loose and cracked FeS layers to the dense FeCO₃ and Fe₂O₃ layers, enhancing the corrosion resistance of the FG20 steel surface.