Comparative Analysis on Results from Corrosion Tests of Dual Phase Steel and Nickel-base Alloy

Addressing the hi-temperature and high-pressure corrosive service conditions involving the coexistence of H₂S,CO₂ and Cl^-,comparative tests are conducted to the 22Cr and 25Cr dual phase stainless steels,and the 028 ferronickel-base alloy and G-3 nickel-base alloy.The elements like Cl-concentration,temperature and liquid mobility etc.which influence the velocity of general or spot corrosion of different anti-corrosion alloy tubular products are analyzed.The test results demonstrate that when Cl-mass concentration is less than 120 g/L,the dual phase steel possesses rather fine corrosion resistance,and can be widely used as the material to produce the tubing or the oil string casing,and when Cl-mass concentration is higher than 120 g/L,the ferronickel-base alloy or the nickel-base alloy possesses satisfactory corrosion resistance,whereas the dual phase steel can be only used to produce tubings with a limited service span as designed.