Author(s)

José Luis Mora-Mendoza¹, Mónica Jazmín Hernández-Gayosso², Daniel Antonio Morales-Serrat¹, Octaviano Roque-Oms¹, Digna Alejandra Del Angel¹, Gerardo Zavala-Olivares²

¹Petróleos Mexicanos, Marina Nacional 329, Col. Petróleos Mexicanos, CDMX, Ciudad de México, México.
²Instituto Mexicano del Petróleo, Eje Central Lázaro Cárdenas Norte 152, Col. San Bartolo Atepehuacan, CDMX, Ciudad de México, México.

The high number of leak events that took place in recent years at a 25.4 cm (10”)Ø pipeline transporting anhydrous liquid ammonia, located in the Southeast of Mexico, was the main reason to carry out a number of field studies and laboratory tests that helped establish not only the failure causes but also mitigation and control solutions. The performed activities included direct evaluation at failure sites, total repair programs, metallographic studies and pipeline flexibility analyses. The obtained results were useful to conclude that the failures obeyed a cracking mechanism by Stress Corrosion Cracking (SCC) which was caused by the combined effect of different factors: high stress resistance, high hardness of the base metal with a microstructure prone to brittleness and residual strains originated during the pipeline construction. From the operative, logistic and financial standpoints, it is not feasible to release the stress of approximately 22 km of pipeline. Therefore, the only viable solution is to install a new pipeline with suitable fabrication, construction and installation specifications aimed at preventing the SCC phenomenon.

Stress Corrosion Cracking, Residual Stress, Ammonia Transporting Pipeline

Mora-Mendoza, J. , Hernández-Gayosso, M. , Morales-Serrat, D. , Roque-Oms, O. , Angel, D. and Zavala-Olivares, G. (2016) Evaluation of Stress Corrosion Cracking Damage to an API 5L X52 Pipeline Transporting Ammonia: A Case Study. Materials Sciences and Applications, 7, 610-622. doi: 10.4236/msa.2016.710050.