Cathodic Induction of Hydrogen Blistering on Carbon Steel in Alkaline Sour Environment

CORROSION / Volume 67 / Issue 8 / CORROSION SCIENCE (2011)

Cathodic Induction of Hydrogen Blistering on Carbon Steel in Alkaline Sour Environment

M. A. Domínguez-Aguilar¹, O. Olivares-Xometl², N. V. Likhanova¹, and M. López-Fuentes²

¹Programa de Investigación y Posgrado, Instituto Mexicano del Petróleo, Eje Central Norte Lázaro Cárdenas No. 152, Col. San Bartolo Atepehuacan, México 07730, D.F.
²Facultad de Ingeniería Química, Benemérita Universidad Autónoma de Puebla, Av. San Claudio y 18 Sur, Col. San Manuel, Ciudad Universitaria, Puebla, 72570 Puebla, México

Abstract

Hydrogen blistering was electrochemically induced on mild steel immersed in alkaline sour solution by cathodic reduction to study the onset of blistering. Test solution attempted to emulate that associated with water formed in catalytic cracking units of oil refinery plants with cyanide ions.

Chronoamperometry method allowed blister diameter and density be tuned by potential pulses and testing time. A theoretical formula was used to calculate critical radius before blistering onset, assuming a depth for hydrogen implantation. A reasonable correlation was found between these measurements and those experimentally determined. The critical radius for blistering initiation seems to be ascribed to a stress higher than the yield stress of material. Blistering rupture displayed material tearing so that a ductile fracture appears to be a consequence of the aerostatic pressure of molecular hydrogen

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