Corrosion Fundamentals & General Damage Mechanisms

Module 1 – Introduction to Corrosion in Oil & Gas

• What is corrosion?
• Why corrosion is critical in oil & gas facilities
• Difference between:
• Corrosion vs damage mechanism
• Degradation vs failure
• Role of API RP 571
• How corrosion knowledge supports:

• API 510 / 570 / 653 inspections
• RBI and FFS decisions

Module 2 – Corrosion Basics & Driving Factors

• Electrochemical basics (simple explanation)

• Key factors influencing corrosion:
  • Material
  • Temperature
  • Pressure
  • Fluid composition

• Role of:
• Water
• CO₂
• H₂S
• Oxygen
• Introduction to corrosion rate concept

• API 571 reference examples:
  • CO₂ corrosion (Sweet corrosion)
  • Oxygen-related corrosion

Module 3 – Uniform & Localized Corrosion

• Uniform corrosion
• Pitting corrosion
• Crevice corrosion
• Under-deposit corrosion.

API RP 571 examples:

• Under-deposit corrosion in carbon steel piping
• Pitting corrosion in stagnant water systems
• Crevice corrosion under gaskets and supports

Module 4 – Galvanic & Environment-Assisted Corrosion

• Galvanic corrosion:
  • Dissimilar metals
  • Area ratio effect
• Environment-assisted corrosion overview

API RP 571 examples:

• Galvanic corrosion between carbon steel and stainless steel
• Localized attack near welds and attachments

Process-Related & Metallurgical Damage Mechanisms

Module 1 – CO₂, H₂S & Wet Gas Corrosion

• CO₂ corrosion (Sweet corrosion)
• H₂S corrosion (Sour service)
• Role of water condensation
• Effect of flow regime

API RP 571 examples:

• CO₂ corrosion in gas pipelines
• H₂S corrosion in separators and piping
• Corrosion in low points of wet gas systems

Module 2 – High-Temperature Corrosion & Oxidation

• Oxidation
• Sulfidation
• High-temperature corrosion overview

API RP 571 examples:

• Sulfidation in carbon steel piping
• Oxidation of furnace tubes
• Metal loss at elevated temperatures

Module 3 – Hydrogen Damage Mechanisms

• Hydrogen blistering
• Hydrogen-induced cracking (HIC)
• Stress-oriented HIC (SOHIC)
• High-temperature hydrogen attack (HTHA – awareness level

API RP 571 examples:

• Blistering in pressure vessels
• HIC in sour service carbon steel
• HTHA risk zones in hydrogen service units

Module 4 – Cracking & Metallurgical Damage

• Stress corrosion cracking (SCC)
• Sulfide stress cracking (SSC)
• Thermal fatigue (intro)

API RP 571 examples:

• Chloride SCC in stainless steel
• SSC in high-strength carbon steel

Cracking near weld heat-affected zones

Corrosion Control, Monitoring & Practical Application

Module 1 – Corrosion Control & Prevention Strategies

• Material selection
• Corrosion allowance
• Coatings and linings
• Cathodic protection (overview)
• Chemical inhibition

API RP 571 linkage:

• Selecting controls based on damage mechanism

Module 2 – Inspection & Monitoring Techniques

• Visual inspection indicators
• Thickness measurement strategies
• Corrosion monitoring tools:
  • Coupons
  • Probes (overview)
• Identifying high-risk locations

API RP 571 examples:

• Monitoring UDC-prone systems
• TML selection based on damage mechanisms

Module 3 – Integrating Corrosion Knowledge with Inspection Codes

• Damage mechanisms vs equipment type:
  • Vessels
  • Piping
  • Tanks

• How corrosion affects:
  • Inspection intervals
  • RBI decisions
  • Repair planning

• Common mistakes when damage mechanisms are misunderstood

Module 4 – Case Studies & Practical Scenarios

• Case study 1:
  • Under-deposit corrosion in piping
• Case study 2:
  • CO₂ corrosion in gas pipeline
• Case study 3:
  • Chloride SCC in stainless steel
• Group discussion:
  • Identify mechanism
  • Likely causes
  • Suitable control measures