Corrosion Behavior of 20 Steel in Multi-Factor Corrosion Environment of Water Gathering and Transportation

The corrosion behavior of 20 steel in multi-factor corrosion environment of water gathering and transportation was studied by means of response surface method (RSM). The quantitative relationship of corrosion current density (J_corr) with temperature, dissolved oxygen concentration, SRB concentration, H₂S concentration and their coupling effects was established through designed experiments. Meanwhile, the significance of the model and each factor was analyzed by means of analysis of variance. The results show that the temperature, dissolved oxygen concentration, SRB concentration, coupling of temperature and SRB concentration, coupling of SRB concentration and dissolved oxygen concentration had significant effects on the corrosion current density. However, the H₂S concentration and its coupling with other factors had no significant effects when the mass fraction of H₂S was in the range of 0-529 mg/kg. Pareto weight analysis displayed that the effects of single factors and coupling factors on the corrosion current density from large to small were: temperature (64.90%), dissolved oxygen concentration (15.27%), coupling of temperature and dissolved oxygen concentration (9.39%), coupling of temperature and SRB concentration (5.29%), SRB concentration (2.67%), coupling of SRB concentration and dissolved oxygen concentration (2.3%).