Effects of thermal spray aluminium coating on SSC and HIC resistance of high strength steel in a sour environment

Abstract

Flexible risers are critical equipment for the production of oil and gas in offshore fields around the world. The annulus region may condense acidic water containing H 2 S exposing the tensile armour steel wires to a sour environment, which may promote sulphide stress cracking (SSC) and/or hydrogen-induced cracking (HIC). This work aims to evaluate through electrochemical and constant displacement tests the effectiveness of thermal spray aluminium (TSA) coating to mitigate SSC and HIC in high strength steel used to manufacture the tensile armour of a flexible riser. Electrochemical tests confirmed the anodic behaviour of the coating against the steel and estimated a service life of 2.5 years. The constant displacement test indicated that the non-coated samples failed by SSC although some cracks were also found in the samples mid-section due to HIC. For Al-coated samples, no signs of SSC and HIC were observed. The TSA coating showed a dual barrier effect, hindering either corrosion of steel or hydrogen up-taking, and neither SSC nor HIC was observed. Samples with a coating defect were cathodically protected and no HIC was observed.

Carbon Dioxide Corrosion Mechanisms: Historical Development and Key Parameters of CO2-H2O Systems

“…The TSA coating protected the carbon steel surface, and no localized corrosion was observed at 40 °C and 4 bar of CO 2 . Similarly, a TSA coating was applied by Bertoncello et al [124] and proved to be effective for suppressing sulfide stress cracking (SSC) and hydrogen-induced cracking (HIC) of tensile armor steel wires in a sour environment…”

Addressing Hydrogen Sulfide Corrosion in Oil and Gas Industries: A Sustainable Perspective

“…This intricate process includes hydrogen diffusion into the steel, forming gas pockets, and subsequent pressure buildup, ultimately resulting in pipeline cracks and failure. Various factors significantly influence HIC, including the steel composition, pressure, temperature, and hydrogen concentration [51]. Therefore, implementing appropriate pipeline design, maintenance, and monitoring measures is crucial to mitigate the risk of hydrogen-induced cracking.…”

Characterization of Boride Coatings on AISI 8620 Steels without and with Hydrogen Permeation

“…One of the alternatives for preventing hydrogen embitterment is modifying the metal surface, producing a barrier for hydrogen difusion into a metal [10,11]. Tese barriers, such as carbides and nitrides, extend the service life of metallic materials [12].…”