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Metallurgical Laboratory
Boiler tube failures continue to be the leading cause of costly down time. Diagnosis of the root cause is critical to determining appropriate corrective action. Our metallurgical laboratory is dedicated to providing you with a comprehensive inspection and metallurgical assessment, from initial diagnosis in the field to a metallurgical analysis in our own laboratory facilities.
To complement the assessment, we issue a thorough report on the inspection findings, including color photographs and all metallurgical and testing results. Full-time metallurgical personnel staff our laboratory, with expertise in essentially all ASTM designation tubing and pipe products used in most boilers. This includes not only carbon and low alloy steels, but also more exotic stainless steels and other metal alloys. We provide services for all OEM steam generating, fuel burning and other ancillary equipment, including environmental systems and equipment.
- Metallurgical Analysis
- Failure Analysis
- Replication Analysis
- Remaining Creep life
Conducting assessments of boiler tube microstructure can reveal deterioration resulting from corrosion, cracking, thermal aging, or mechanical deformation. Accurate tubing assessment provides important data for determining your boiler’s overall condition as part of remaining life assessment. Tube samples are also analyzed for metallurgical and manufacturing defects and internal and external surface discontinuities. Using optical and electron microscopes, we evaluate tube sections and hardness and dimensional measurements are also made to further assess the tube’s condition. A complete metallurgical assessment of a component includes: visual inspection, dimensional measurements, micro structural assessment, hardness measurements, and chemical analysis of internal and/or external depositions, remaining creep life (as appropriate) and deposit weight density calculations (as appropriate).
A failure analysis includes a full metallurgical analysis, as well as a description of the failure mode, and recommendations inspection of similar components, replacement/repair, and changes to operating conditions.
Some of the more common failure mechanisms in boiler components include:
• Fatigue
• Corrosion Fatigue
• Creep
• Corrosion
o Fireside corrosion
o Hydrogen damage
o Acid phosphate corrosion
o Caustic gouging
o Acid dew point corrosion
o Liquid ash corrosion
o Stress corrosion cracking
• Over temperature conditions (including spheroidization and graphitization)
• Material defects
• Weld defects
• Stress overload
• Operational Issues
Replication provides the same level of micro structural detail as a sample sent to the Laboratory.
Replication is commonly performed at the heat-affected-zone (HAZ) of welds, an area particularly susceptible to creep damage.
The metal temperature can be estimated from the thickness of the internal oxide/scale of a tube. Estimate of the stress is based on the tube dimensions and the operating pressure of the unit.
Remaining creep life calculations are performed on all superheater and Reheater tube samples received in the Metallurgical Laboratory; readings can also be taken in the field with Ultrasonics. In this way, hundreds of the tubes can be analyzed for RCL, creating a map of a component or unit. Based on the results of the RCL calculations, recommendations can be made about the components, including changes in the operating conditions, tube replacement, or material upgrades.