Modification of Corrosion Resistance of the Plain Carbon Steels by Pulsed Electric Current

Abstract

The fracture of pipelines caused by corrosion cracks and the resulting oil and gas leakage can lead to great environmental pollution and economic losses. These negative effects are due to serious corrosion of the plain carbon steels used for armor of flexible pipe in oil and gas transmission medium. However, corrosion resistance of carbon steel armors has yet to be improved. In this study, the relationship between corrosion resistance and pearlite fraction in the plain carbon steels has been investigated through the application of pulsed electric current. Based on immersion test and electrochemical measurement, pulsed electric current increases the corrosion resistance of the plain carbon steels by reducing the fraction of pearlite phase. Pitting corrosion, which tends to initiate by galvanic corrosion of ferrite and cementite, is therefore inhibited due to the decrease in pearlite fraction (mixture of ferrite and cementite) under electropulsing.

Synergistic Balance of Strength and Corrosion Resistance in Al–Mg–Er Alloys

“…7a. This demonstrates that Er addition leads to an evident increase in corrosion potential (E corr ) [25]. The polarization curves of samples treated at different temperatures exhibit certain differences.…”

Improvement of Corrosion Resistance of Simulated Weld Heat Affected Zone in High Strength Pipeline Steel Using Electropulsing

“…According to the dynamic potential polarization curves, the corrosion potential, corrosion current density and corrosion rate of each sample could be obtained according to the Tafel straight line extrapolation method 29) and Eq. (6), 18) as shown in Table 1.…”

“…4,12,17) As a convenient, energy-saving and efficient instantaneous high-energy input method, electric pulse can modify the microstructure of metallic materials in a very short time. 18) With the development of electroplastic theory and electromigration theory, electric pulse processing technology has been paid attention again, and has been more and more widely used in improving the performance of metallic materials. 19,20) Electric pulse treatment has an important influence on microstructures evolution and corrosion resistance of metallic materials.…”

“…It was found that electric pulse treatment could induce grain refinement of low carbon steel, and smash the carburized strips in strain pearlite steel to pieces, so as to improve its corrosion resistance. 18,21,22) In addition, electric pulse treatment can significantly accelerate the dislocation migration rate of metallic materials, promote dislocation annihilation, and reduce residual stress. [23][24][25] However, the effect of electric pulse treatment on corrosion resistance of HAZ in welded joint has been rarely reported.…”

Residual Stress Removal Under Pulsed Electric Current

“…The irreversible strains corresponded to plastic deformation of the material [11]. Tang et al [14][15][16][17][18][19][20] and other investigators [21][22][23][24][25][26][27] recently conducted a series of extensive studies on engineering applications of the electroplastic effect.…”