Study On Corrosion Behavior Of X52 Steel In Marine Environment

In recent years,the exploration and development of marine oil and gas resources has gradually increased.A large number of pipelines have been used in the marine environment and have been affected by seawater corrosion for a long time.Compared with the terrestrial environment,there are more corrosive media in the marine environment,and the pipeline is more vulnerable to corrosion,which will reduce the service life of the pipeline and improve the risk of pipeline leakage.X52 pipeline steel is a low alloy high strength steel,which is widely used in marine environment because of its good performance.X52 pipeline steel runs in the marine environment for a long time and is vulnerable to a variety of corrosion factors,mainly including p H value,hydrostatic pressure,dissolved oxygen content and so on.Under the influence of these factors,X52 pipeline steel is prone to corrosion and cause serious consequences.Therefore,it is necessary to study the corrosion behavior of X52 pipeline steel in marine environment.This paper mainly studies the effects of different dissolved oxygen concentration,p H value and hydrostatic pressure on the corrosion behavior of X52 pipeline steel in marine environment.The corrosion behavior of X52 steel in marine environment was studied by electrochemical experiment and metallographic microscope imaging technology.The experimental results show that when other experimental conditions remain unchanged,the p H value decreases from 8.2 to 6.4 and the corrosion current density increases from 6.02 increased to 23.9μA/cm~2,the corrosion rate increases from 0.072 to 0.285mm/a,and the corrosion rate is inversely proportional to p H value.When the p H value in the solution is 6.4,the resistance of polarization resistance is the smallest,the resistance of X52pipeline steel in the corrosion process is the smallest,the corrosion pits on the metal surface are the largest,the number is the largest,and the corrosion degree is the most serious.In the marine environment simulation solution,when the dissolved oxygen content of the solution decreases from 10 to 0.3mg/L,the corrosion current density increases from 15.4 reduced to 5.12μA/cm~2,the corrosion rate decreases from 0.184 to 0.061mm/a,and the corrosion rate is directly proportional to the dissolved oxygen content.When the content of dissolved oxygen in the solution is 10mg/L,the resistance of polarization resistance is the smallest,the resistance of X52 pipeline steel in the corrosion process is the smallest,the corrosion pits on the metal surface are the largest,the number is the largest,and the corrosion degree is the most serious.In the marine environment simulation solution,when the hydrostatic pressure increases from 0 to 3MPa,the corrosion current density increases from 4.17 to 21.9μA/cm~2,the corrosion rate increases from 0.049 to0.261mm/a,and the corrosion rate is directly proportional to the purified water pressure.When the hydrostatic pressure in the solution reaches 3MPa,the resistance value of polarization resistance is the smallest,the resistance of X52 pipeline steel in the corrosion process is the smallest,the number of corrosion pits on the metal surface is the largest,and the corrosion degree is the most serious.