Galvanic Corrosion on Partial Surface of P110 Steel in H₂S/CO₂ Environment

Through the simulation of galvanic current tracking test,the laws of the galvanic current between the corrosion film of P110 steel surface and the metal with temperature,time area ratio and other factors were studied.The results showed that the P110 electrode covered by film suffered anodic dissolution,the bare electrode acted as a cathode at 40 ℃.In the initial coupling stage at 60 ℃,P110 electrode covered by film suffered anodic dissolution,but current reversing between coupling electrodes happened quickly,and bare electrode corroded as an anode.At 60 ℃,the potentials of different electrodes with various ratios of bare electrode area / film covering electrode areas showed small diffrences,and the potentials moved in the negative direction and the absolute value of the galvanic current density decreased with the increase of the ratio of anodearea/cathode area.Under the steady conditions,the current density between bare electrode and film covered electrode was close to zero.Under the dynamic changing conditions,it was likely to form the situation of small anode and big cathode,which led to be hard for polarization and to be easy for corrosion perforation.