In order to proactively plan for boiler tubing replacements and prevent failures, it is necessary to detect service-related damage at an early stage.
AMCO Integrity provides a comprehensive tube life management program that includes NDE, metallurgical testing, and analytical life studies. A key part is to determining the metallurgical condition of a damaged component can provide information on whether it needs repair or replacement, or if it is suitable for continued service in its current condition. In this program, AMCO is performing a metallurgical analysis on tube samples to determine their microstructural current condition.
A metallurgical assessment of components, combined with an understanding of the failure mechanisms of concern, can establish how much longer the component can provide reliable service. This information allows you to plan refurbishment or replacement prior to unexpected catastrophic failure or other damage.
Visual analysis of failed equipment or its component or samples to determine the physical characteristics of failure.
Dimensional measurements are generally taken on ring-sections removed from tubes in order to identify the extent and location of any wall loss or if swelling is present. Wall loss can occur on either the OD or ID, and can indicate corrosion, erosion, steam washing, etc.
The depth of pitting or other surface damage can also be measured. Swelling of the tube, when present, can be evaluated and correlated to creep damage in the tube material and remaining life.
Equipment operates best when all of the parts are made of the correct materials. Using an XRF gun, we quantitatively analyze alloying and trace elements in the component and compare the test results with the appropriate alloy specification. We then bring any discrepancies to your attention.
Metallurgical analysis reveals the condition and makeup of your materials with macro, micro and SEM examinations. This assessment performed on components that sustain in-service degradation mechanisms can provide a benchmark as to the current condition and allow a more educated prediction of remaining useful life.
Our metallurgical assessment services can help prevent the loss of critical components by directing maintenance efforts. We can also provide guidance to non-destructive inspection teams to direct them towards more damaged areas or pare down the work scope to avoid unnecessary inspections.
The microstructure of a tube will help us to understand the thermal history of the sample, including any degradation or transformation that may have taken place due to prolonged exposure to operating temperatures or short-term exposure to excessive temperatures. Samples are analyzed for metallurgical and manufacturing defects, heat treatment and internal and external surface discontinuities.
We evaluate the microstructure using optical microscopes and compare the results with the code and our internal technical literature as well as our internal e-Atlas of microstructures.
SEM is an extremely high magnification microscope which provides images and elemental analysis of materials or chemicals top down or in cross-section.
In-place metallography allows for a quick onsite component evaluation. It can reveal whether a component has suffered from overheating or other microstructural damage that nondestructive evaluation techniques cannot detect. We at AMCO has on-site Structure Analysis Software which can generate result on the site itself.
Hardness measurements are used to determine if any thermal softening has occurred in the tube due to long-term exposure at high temperatures. Hardness testing of failed component sample to assess the material hardness value from different areas.
Hardness can also provide insight to any microstructural transformation that may have taken place, which can lead to either higher or lower hardness values. Hardness values can be used to estimate tensile strength for most ferrous materials, and low values can be an indication of shorter remaining life intervals.
Internal and External Oxides/Deposits
Scaling and deposit buildup can reduce efficiency by acting as barriers to heat transfer, promote corrosion by acting as concentration sites for corrosive species, or can result from corrosive attack. Samples are collected during on-site inspections and taken back to our laboratory for analysis. We employ energy dispersive x-ray spectroscopy to identify constituents in a sample. Scale and deposit analysis can determine the nature, sources, and effects of deposits. We then suggest steps you can take to mitigate their formation.
Characterization of OD and ID oxides or deposits can also be performed using optical light microscopy as well as utilizing a scanning electron microscope (SEM).
The oxide thickness on the internal surface of steam-touched tubes can also be used to estimate tube metal temperature during operation, which is useful in remaining life evaluations.
Wall thickness measurement as part of non-destructive testing is one of the most common uses of ultrasonic technologies. In addition to the classic measurement of wall thickness as part of quality control, our precise wall thickness measurement devices can also be used to detect damage caused by erosion and corrosion on the tube.
Life Assessment Calculation
Life predictions based on mean and lower bound properties will be provided. An analysis of the sensitivity of the prediction to the assumptions made with regard to carburization will be included.