Localized electrochemical behavior in welded API 5L X70 steel pipeline joints

By Ana Cristina Calil Ramos, Vanessa de Freitas Cunha Lins, Fernando Cotting & Idalina Vieira Aoki

1 min read

Presented at the 2023 Rio Pipelines Conference in Rio de Janeiro, Brazil.

The present work evaluates the API 5L X70 steel corrosion resistance of welded longitudinal joint samples taken from different pipeline pipe manufacturers. The samples are evaluated using potentiodynamic polarization techniques, electrochemical impedance spectroscopy (EIS), as well as through localized testing using a microcell and the vibrating electrode scanning technique (SVET). The electrolyte used is iron ore beneficiation plant process water used for pipeline flushing. Despite the similar alloy composition, the results show that the electrochemical behavior is different for each sample, revealing that one of the alloys is susceptible to localized attack.

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