Corrosion of X65 Pipeline Steel Under Deposit and Effect of Corrosion Inhibitor

• Main Authors: XU Yun-ze, HUANG Yi, YING Liang, WANG Xiao-na, YANG Fei
• Format: Article
• Language: zho
• Published: Journal of Materials Engineering 2016-10-01
• Series: Journal of Materials Engineering
• Subjects: X65 pipeline steel; under deposit corrosion; PBTCA; galvanic corrosion
• Online Access: http://jme.biam.ac.cn/CN/10.11868/j.issn.1001-4381.2016.10.015

Effect of the deposit on the electrochemical parameters of X65 pipeline steel in oxygen contained sodium chloride solution was studied by EIS and PDS methods. The galvanic corrosion behavior under deposit and effect of different concentration of corrosion inhibitor PBTCA were studied by electrical resistance (ER) method combined with ZRA. The results show that the corrosion potential of X65 steel shifts negatively as SiO₂ covering its surface and the corrosion rate becomes lower. When the galvanic couple specimen with deposit is electrically connected with the specimen without deposit, anodic polarization occurs on X65 steel under deposit and the galvanic current density decreases from 120<i>μ</i>A/cm² to 50<i>μ</i>A/cm²and keeps stable. As 5&#215;10^-5, 8&#215;10^-5 and 3&#215;10^-4 PBTCA were introduced into the solution, the galvanic current density reaches the highest 1300<i>μ</i>A/cm² and then decreases to 610<i>μ</i>A/cm² keeping stable around 610<i>μ</i>A/cm², corrosion rate of X65 steel under deposit reaches 6.11mm/a. PBTCA accelerates the corrosion of X65 steel under deposit in oxygen contained solution. Through the investigation on the surface of the specimens, serious local corrosion occurs on the X65 steel surface under deposit.