Assets can be broadly divided into two different classes based on their asset integrity management philosophy or mentality. In one class, corrosion control relies primarily on traditional asset integrity management activities, whereas the other employs more modern asset integrity management. Assets in the latter category generally exhibit lower corrosion rates and fewer leaks, while corrosion remains a major integrity threat for the former.
This article investigates water chemistry-driven degradation mechanisms in cement-mortar-lined (CML) steel pipelines conveying desalinated water following the transition from multi-stage flash to seawater reverse osmosis (SWRO) desalination. Field case histories demonstrate that destabilized post-treatment chemistry—characterized by low alkalinity, insufficient calcium hardness, predominantly negative or near-zero Langelier Saturation Index, and elevated chloride concentrations—promotes calcium leaching, loss of cement alkalinity, and increased CML permeability. These processes compromise steel passivation and create aggressive crevice conditions at the CML/steel interface, resulting in localized corrosion, volumetric expansion of corrosion products, debonding, and lining delamination. The findings clearly indicate that controlled water stabilization is a critical prerequisite for the long-term integrity and reliability of CML-lined transmission pipelines conveying SWRO-produced water.1
In water applications, material selection is based on corrosion resistance, formability, and cost. While S30403A is a standard choice, where the fluid corrosiveness exceeds its tolerance, a superior alloy grade such as S31603A is required. To offer a more economical and environmental alternative, Aperam developed the new 316A grade. A comparative study—including localized, crevice, and uniform corrosion assessments using electrochemical methods and intergranular corrosion trials—confirms this grade achieves corrosion resistance similar to S31603 across different temperatures and media. Now registered in ASTM standards1 as S30416, 316A provides a cost-effective solution for demanding water environments without compromising performance.2
Seawater injection facilities are complex environments prone to biofouling and microbiologically influenced corrosion. This study details a comprehensive microbiological audit of a major seawater treatment facility to characterize the microbial population of the whole facility and evaluate efficacy of the incumbent biocide treatment program. By integrating adenosine triphosphate measurements, culture-based methods, quantitative polymerase chain reaction, and next-generation sequencing, the research identifies the specific microbial populations present and tracks their response to treatment. The results demonstrate how integrated data provide a superior assessment of biocide performance compared to traditional monitoring. This multi-faceted strategy enables operators to optimize chemical programs by accurately targeting the actual microbial community within the network.
Service life of unbonded flexible risers in offshore operations may be limited by designs based on conservative corrosion fatigue S-N curves. A new corrosion fatigue test methodology simulates the steady-state annulus environment of long-operated pipes with realistic carbon dioxide (CO2) and hydrogen sulfide (H2S) partial pressures, supersaturation of dissolved corrosion products, protective iron carbonate (FeCO3) film on carbon steel armor wire surfaces, and corrosion rates around 0.01 mm/y. This yields more accurate S-N curves (stress vs. number of cycles to failure) tailored to field conditions, enabling riser lifetime extensions. The service life of six risers was extended beyond original design life without compromising safety. This methodology improves fatigue life predictions and supports optimized riser management.
Understanding the effect of stress distribution during sulfide stress cracking testing is essential for obtaining reliable results. Therefore, the local stresses in four-point bend transverse-weld specimens were simulated using the finite element method. The analysis revealed localized plastic strain in the heat-affected zone of the longitudinal submerged arc weld. When specimens were loaded to 90% of actual yield strength, the resulting stresses exceeded those found in a pressurized pipe by up to 60%. The findings were validated through internal loading of full-ring test specimens in accordance with ISO 3845 at various stress levels. This article summarizes the study presented elsewhere.1
The revision of NSF/ANSI/CAN 611 resulted in the formal adoption of NSF/ANSI/CAN 600,2 Health Effects Evaluation and Criteria for Chemicals in Drinking Water, and the removal of Annexes A and D addressing extractable limits. Mandatory implementation of NSF 600 extractable criteria on January 1, 2023, significantly altered the regulatory framework governing coatings used in potable water systems throughout North America. By substantially reducing allowable extractable limits for common aromatic solvents, the standard required widespread reformulation and re-evaluation of traditional coating technologies. While industry discussion has largely centered on regulatory compliance, the broader implications for corrosion protection performance, asset management strategy, and life-cycle cost are equally significant. This article updates AMPP paper C2022-180263 and reviews the regulatory evolution from NSF 61 to NSF 600, examines technology adaptation within the coatings industry, and presents an asset-management-based framework for selecting potable water coating systems that balance health compliance, durability, risk mitigation, and long-term value.
Carbon fiber-reinforced polymer (CFRP) is a structural lining system for repair and renewal of large diameter (30 to 210 in [0.76 to 5.33 m]) pressure pipes in water and wastewater systems. Between 2009 and 2018, the American Water Works Association (AWWA) developed AWWA Standard C305, “CFRP Renewal and Strengthening of Prestressed Concrete Cylinder Pipe (PCCP).” CFRP’s success with PCCP has led to widespread application on other pipe materials, including steel, iron, and reinforced concrete pipe materials. This article summarizes 25 years of experience, practices, and factors influencing longterm performance. CFRP performance is compared with other structural rehabilitation methods.
Atmospheric corrosion, a prevalent and persistent challenge, continues to be a topic of significant interest in the field of materials science and engineering, including the automotive industry. Atmospheric corrosion becomes more complex in cold regions such as Alaska due to the extensive use of deicing salts. This study evaluates the combined effect of salt exposure and exposure angle on carbon steel, providing insights to inform protective strategies for automotive applications. These findings are not only essential for infrastructure longevity and public safety but also for economic prudence, avoiding wasteful use of resources expended on metal refinement.
Microbiologically influenced corrosion (MIC) is an electrochemical process driven by microorganisms in oil and gas pipelines. MIC begins with biofilm formation, where microbes generate corrosive metabolic byproducts. It includes aerobic and/or anaerobic mechanisms, with anaerobes thriving without oxygen. Key contributors include sulfate-reducing bacteria (SRB), sulfur-oxidizing bacteria (SOB), iron-reducing bacteria (IRB), iron-oxidizing bacteria, acid-producing bacteria, acid-reducing bacteria, and methanogens. Quantitative polymerase chain reaction (qPCR) analysis confirms microbial involvement in pipeline corrosion. This article presents case studies linking MIC—primarily from SRB, SOB, and IRB—to metallurgical failures in pipeline steels.
Analysis of five soil samples from a gas pipeline accident site revealed varying corrosivity toward steel pipe, with corrosion rates ranging from 0.028 to 0.111 mm/yA. The presence of water-soluble salts in moistened soil and the alternation of different soil types intensified aggressiveness. These conditions promoted the formation of macro-corrosion pairs at soil boundaries and facilitated electrochemical processes in thin electrolyte films beneath damaged coatings, accelerating steel degradation. Overall, the findings highlight significant corrosion-related risks contributing to pipeline failure and structural deterioration.
