Boiler Tube Failure Analysis

Why boiler tubes fail

Boiler tubes are critical components in petrochemical facilities and power plants, and they operate under some of the harshest conditions in the plant. Identifying why a tube failed requires more than a fracture surface: it demands an understanding of water chemistry, operating history, and microstructure together. Our investigations bring all three to bear so the corrective action addresses the real cause rather than the symptom.

Common failure mechanisms

Corrosion-related failures

On the waterside (internal) we look for oxygen pitting, acid attack, caustic gouging, and hydrogen damage. On the fireside (external), the culprits are typically sulfidation, chloride-induced corrosion, and low-temperature dew-point corrosion.

Erosion and erosion-corrosion

• Fly ash erosion in coal-fired units
• Steam or water impingement in high-velocity regions
• Erosion-corrosion driven by turbulent flow

Stress corrosion cracking (SCC)

• Chloride SCC in austenitic stainless-steel tubes
• Caustic SCC in boiler water circuits

Overheating and creep damage

Prolonged or localized overheating produces microstructural degradation, creep voids, and grain-boundary damage, and can lead to tube swelling, bulging, or outright rupture at hot spots.

Fatigue and mechanical failures

• Thermal fatigue from startup and shutdown cycles
• Vibration-induced fatigue
• Dents, gouges, or improper installation damage

Operational and maintenance issues

Many failures trace back to poor water chemistry, scaling and deposits, improper startup/shutdown procedures, inadequate cleaning, or weld defects, issues that are correctable once identified.

How we investigate

Each failed section is examined with metallography, chemical and deposit analysis, and hardness testing, correlated against the unit's water chemistry and operating record. Documented case histories across multiple material types and mechanisms inform every diagnosis and the recommendations that follow.