Analysis of premature corrosion failure in industrial assets

In industrial sectors such as oil and gas, petrochemicals, power generation, and mining, premature failures represent a critical challenge in asset management. These failures, occurring before the expected service life of equipment, disrupt production and expose structural weaknesses in facilities. They reveal low operational reliability and can result in costly unplanned shutdowns, environmental damage, or even accidents.

Among the most common causes of such events are corrosion, particularly stress corrosion cracking (SCC), and vibration-induced fatigue. These mechanisms often act imperceptibly until triggering the sudden collapse of a component. This article explores the failure analysis of corrosion in industrial assets, addressing its detection, mechanisms, prevention, and relationship with the control of operational variables.

What is a premature failure, and why must it be analyzed?

A premature failure is defined as the failure of a component or system that occurs before reaching its estimated useful life, even when operating under what are considered normal conditions. In metallic components, corrosion is one of the most decisive contributing factors. It can appear either locally (as pitting or cracking) or generally, gradually compromising the structural integrity of the material.

This chemical degradation is often aggravated by mechanical factors such as vibrations, which introduce alternating stresses on structures. When these stresses coexist with a corrosive environment, a synergistic damage mechanism known as corrosion-fatigue emerges, accelerating deterioration significantly.

In industrial environments, premature failures manifest as leaks, ruptures, deformations, cracking, or loss of structural integrity, leading to operational, financial, and safety-related consequences. Ultimately, they serve as a warning sign that something was inadequately addressed during the design, construction, operation, or maintenance stages.

Corrosion as a root cause of premature failures

Corrosion is a natural electrochemical reaction that deteriorates metallic materials when interacting with their environment. Although it is considered inevitable in most industrial processes, corrosion should occur in a progressive and controlled manner, within the design margins of the equipment. However, several factors can accelerate this phenomenon, resulting in early failures:

• Inappropriate material selection for the service environment.
• Exposure to aggressive atmospheres (marine, acidic, alkaline).
• Failures in cathodic protection systems and anti-corrosion coatings.
• Overstressing, pressure spikes, or unforeseen temperature conditions.
• Build-up of deposits that promote localized corrosion.
• Lack of online corrosion monitoring.

One of the highest risk mechanisms is stress corrosion cracking (SCC), where the interaction between a corrosive environment and a constant mechanical stress (residual or operational) generates microcracks that evolve into fractures without previous signs.

What is premature failure analysis?

Premature failure analysis is a structured technical process aimed at understanding why a component failed early, identifying the root cause of damage and the contributing conditions.

Its objectives include:

• Identifying the damage mechanism (corrosion, fatigue, erosion, etc.).
• Determining whether the component operated beyond its design specifications.
• Detecting design flaws, assembly errors, or adverse operational conditions.
• Optimizing maintenance and replacement strategies.
• Mitigating systemic risks through corrective and preventive actions.
• Evaluating the need for system design changes (e.g., metallurgy upgrades).

This type of analysis integrates visual, metallographic, chemical, structural, and operational evidence and is especially relevant in environments where industrial asset management depends on long-term reliability.

How to detect Stress Corrosion Cracking (SCC)?

SCC is difficult to detect because it initiates within the material and progresses sub-critically until causing a sudden failure. Its detection requires:

• Phased Array Ultrasonic Testing (PAUT): Detects internal cracks before they propagate.
• In-situ Metallographic Replication: Allows observation of superficial microcrack formation.
• Acoustic Emission Monitoring: Captures the characteristic sound of crack propagation during operation.
• Fractographic Analysis via Scanning Electron Microscopy (SEM): Reveals the typical SCC fracture pattern.

Materials most vulnerable to SCC include low-alloy carbon steels, austenitic stainless steels, and carbon steels exposed to acidic, chloride-rich, or poorly distributed internal stress environments.

Techniques for analyzing premature corrosion failures

A thorough failure analysis requires a combination of mechanical, metallurgical, chemical, and analytical techniques, including:

• Visual and Fractographic Inspection: First step to characterize the fracture.
• SEM (Scanning Electron Microscopy): Identifies failure modes and crack propagation patterns
• X-ray Diffraction or Residual Stress Measurement.
• Chemical and Spectrometric Analysis: Detects impurities or corrosive agents.
• Mechanical Testing: Hardness, tensile, and Charpy impact tests.
• Destructive Testing and Service Condition Simulation.
• Operational Review: Examines historical data, alarms, and operational patterns.
• Risk-Based Inspection (RBI): Establishes inspection priorities based on criticality.
• Traceability Review: Assesses historical operational and maintenance parameters (temperature, pressure, flow, vibration, etc.).

These tools are fundamental when developing strategies for how to prevent corrosion and extend the reliability of industrial components.

Preventing premature failure: A comprehensive approach

An effective prevention strategy must address the phenomenon from multiple angles, with a lifecycle perspective. The most important actions include:

• Proper material selection: Evaluate compatibility between materials and operating media, considering temperature, stress, pH, flow velocity, and fluid chemistry. Resistant alloys like duplex stainless steels, Inconel, or titanium may be necessary in extreme environments.
• Cathodic protection and anti-corrosion coatings: These are fundamental to reducing corrosion rates. Cathodic protection adjusts the electrochemical potential of metal surfaces to achieve protective polarization criteria, while coatings act as physical barriers. Both systems require maintenance and periodic validation.
• Online corrosion monitoring: Use corrosion sensors to detect wall thinning, chemical changes, and aggressive conditions in real time without disrupting operations.
• Operational variable control within design parameters: Most premature corrosion failures stem from operating outside design limits, triggering unforeseen corrosion processes. To avoid this:
  • Control pressure, temperature, fluid velocity, flow rate, and fluid composition.
  • Maintain pH balance and prevent contamination.
  • Avoid mechanical or thermal overloads.
  • Detect abnormal cycles or transient operating conditions.
  • Ensure traceability of operational and maintenance data to correlate anomalies with early deterioration signs and enable early corrective actions.
• Mechanical vibration control: Monitoring and analyzing vibrations is essential. Techniques such as spectral analysis, natural frequency detection, and dynamic balancing can help eliminate one of the most common causes of premature failures.
• Risk-Based Inspection (RBI): RBI allocates resources to the assets with the highest likelihood and consequences of failure, reducing risk without increasing costs. Inspections are designed to be focused and efficient based on risk assessments.
• Technical culture and integrated approach: Implement a comprehensive failure prevention framework that includes design, operation, maintenance, and analysis. This involves technical training, capacity building, and systematic vulnerability assessment.

Conclusions

Corrosion-related failure analysis transforms unplanned events into opportunities for technical learning. However, it must be understood that a premature failure is not an unavoidable consequence, it is a warning that something went wrong before its time.

Addressing this issue requires a multidisciplinary approach, including real-time monitoring, control of operational variables, use of cathodic protection and coatings, application of RBI, and data traceability to ensure timely detection. In-depth analysis, and effective corrective actions that preserve the operational integrity of assets.

References

1. https://inspenet.com/en/articulo/advanced-sensor-technologies/
2. https://en.wikipedia.org/wiki/Metallurgical_failure_analysis
3. https://inspenet.com/en/articulo/ampp-cathodic-protection-program/
4. https://inspenet.com/en/articulo/rbi-technologies-for-atmospheric-tanks/