Steam Turbine NDE service / NDT
Steam turbine NDE service is becoming increasingly important for power plants and other industries using steam turbines in their operations. This service can help detect faults and damages to the turbine components before they result in expensive repairs or complete replacement.
Steam turbines are complex pieces of machinery, requiring regular maintenance and repair to keep them running smoothly. NDE services can provide a comprehensive assessment of the condition of turbine components, allowing any potential issues to be identified early on in order to avoid costly repairs or replacements down the line. The use of these services can also help reduce downtime due to component failure or unexpected breakdowns, thereby improving the efficiency and overall performance of steam turbines.
With a complete portfolio of steam turbine NDE service (Non-Destructive Examination) and steam turbine NDT service (Non-Destructive Testing) inspection services, Signature Blasting Services can help provide exceptional value through our value-based asset management approach and early flaw detection with a high POD (probability of detection) for your steam and gas turbine components.
Steam turbine NDE service plays a vital role in confirming asset integrity and is a major contributor to asset life cycle assessments and planning for asset life extensions. These technologies enable engineers to evaluate component life, and aging and failure mechanisms, which in turn empower plant operators to ensure equipment reliability and to predict when major component overhauls and refurbishment are required.
Steam turbine rotors are subject to service lifetime limitations due to creep, thermal fatigue, and stress corrosion cracking. For example, creep occurs naturally during steady state operation due to centrifugal stresses sustained at high operating temperatures, while thermal fatigue arises through start-up and shut-down cycles. Microscopic cracks may initiate and grow to a size resulting in abrupt fracture. Therefore, the detection, classification, and sizing of such flaws are critical to reliable operation.
No matter how difficult your asset integrity challenge is, we can help provide a solution with our unrivaled spectrum of NDT and NDE technologies. In many cases, we can provide inspection services online and can often complete inspections within aggressive timelines with quality. Selecting the correct NDT technique is fundamental to the safe and reliable life of an operating plant. Our expertise and investment in specialized tools and equipment enable us to carry out NDT and NDE using some of the following techniques to ensure value-optimized and accurate inspection results:
Signature Blasting Services’ is supported by a comprehensive suite of programs for safety, technical training, and quality systems that work to standardize the execution of the service with consistently repeatable results.
Phased Array Ultrasonic Testing
Ultrasound testing (UT) is useful for the detection and location of flaws such as discontinuities, cracks, and delamination as well as material composition analysis, and wall thickness and erosion/corrosion measurements and mapping. UT detects surface and subsurface defects, and has a very high level of accuracy and repeatability in estimating discontinuity size and shape.
The Signature Blasting Services team provides quick, accurate UT results that empower you to make data-informed decisions fast. It has a superior depth of penetration and does not require the same dual-end accessibility or safety protocols that are associated with radiography.
Additionally, Signature Blasting Services also offers Phased array ultrasonic testing (PAUT), which is an advanced type of UT technique that offers the enhanced functionality of performing inspections with the ultrasonic beams of various angles and focal lengths using a single array of transducers, enhancing beam coverage. In PAUT, a software controls the beam angles and focusing is achieved by the application of precisely controlled delays to both the emission pulse and received signal for each element in an array of transducers. PAUT beam sweeps like a searchlight through the object, resulting in a recordable image that helps visualize defects hidden inside a structure or weld; similar to an ultrasound or sonogram used in a hospital.
PAUT offers definitive advantages over conventional UT by providing imaging that can produce more accurate and repeatable results while minimizing human error. It also allows for enhanced coverage of a given from fixed and multiple positions including achieving beam coverage on complex angles and geometries with greater ease and less time. The ability to focus at multiple depths within the material body also improves the ability for assessing the size and scale of critical defects for volumetric inspections.
Some common applications include pressure boundary and non pressure boundary weld inspections, piping integrity checks, and flaw detection on flanges, graylocks, bolts, studs and major components of turbines and generators such as blades, rings, rotors, and stators
Radiography
Radiography is a form of NDT that involves the use of X-ray or Gamma (Iridium 192) radiation to examine parts for flaws or defects that could be detrimental to their intended operation. It is sensitive to changes in thickness and density, corrosion, cracks, and voids. Able to detect both surface and sub-surface defects and with minimum surface preparation required, radiography inspection enables our technicians to accurately locate, size, and identify defects.
At Signature Blasting Services, specialize in using the latest technologies and techniques for radiographic testing projects. Our team of highly experienced radiographers is extremely capable at employing specialty techniques involving geometrically-challenging parts and pieces.
Although it may require a safe work zone during the execution of the work in the field, some of its benefits are: provides a permanent record of inspection, the ability to inspect assembled components, requires minimal surface preparation, and both surface and subsurface crack detection capability.
In terms of the range of use cases, radiography can reveal changes in the thickness of corrosion, voids, and cracks, as well as the functionality of weld examination for quality control, profile imaging, and crack detection in gas and steam turbine components
Eddy Current Testing
Eddy current testing is a highly versatile and efficient branch of NDT that is capable of detecting the most minute surface and near surface defects in conductive materials. A standout advantage of eddy current is that it can detect defects through several layers, including non-conductive surface coatings like paint, and without interference from planar defects.
The eddy current inspection services offered at Signature Blasting Services is a cost-effective technique to inspect and detect metals for surface cracks, pitting, wall loss, and other discontinuities, with high sensitivity and Probability of Detection (PoD). Probes also do not need to directly contact the material, so eddy current inspection’s capabilities extend to conductive materials with physically complex shapes and sizes.
Turbine rotor blades, disks, and spacers experience high levels of mechanical stressors during their operational life, making them susceptible to multiple stress-induced failure modes. The continuous centrifugal loads and the thermal cyclic loads on the blade of a turbine make the attachment point at their root, such as the dovetail joints, particularly prone to fatigue cracking which can inherently decrease the service life of a turbine. Eddy current testing is widely used as part of turbine life cycle assessment and major inspection programs across industries. Additionally, during the maintenance outages, the turbine components are usually blast cleaned to obtain the desired surface finish. Prior to reassembly, eddy current testing is generally performed to check for integrity.
Additional advantages of eddy current inspection include its portable and lightweight kit, immediate availability of results, and minimum part preparation and pre-cleaning. Ultimately, these benefits can help minimize downtime and decrease overall inspection costs.
Magnetic Particle Inspection
Magnetic Particle Inspection (MPI) is an NDT technique used for the detection of surface and near-surface flaws and discontinuities in a wide variety of ferromagnetic materials and components including castings, forgings, and weldments.
A magnetic field is applied to the subject test material, either locally or overall, using a permanent magnet, electromagnet, or hand-held prods. If the material is sound, most of the magnetic flux is expected to be concentrated below the material’s surface. However, if a flaw is present, such that it interferes with the magnetic field, the flux is distorted locally and “leaks” from the surface of the specimen in the region of the flaw.
These flux leakages can be visually detected by applying fine magnetic particles, typically black iron particles or iron oxides, to the surface of the specimen. The particles can also be coated with a fluorescent material for easier and more accurate detection under an ultraviolet lamp in darkened environments.
MPI has use cases both in the lab as well as in the field and is widely used for final inspection following major overhaul, parts receiving inspections, and major asset maintenance inspections and life assessments. Similar to most other NDT/NDE techniques, MPI too can inspect large and irregular shapes, does not require significant surface preparation, provides visible indication, and can be deployed fairly quickly due to its simple setup.
Here at Signature Blasting Service, our portable equipment provides the foundation to provide you with fast, cost-effective, and reliable MPI with our specialty crew.
Liquid Penetrant Inspection
Liquid penetrant inspection technique is widely used across industries to detect surface discontinuities. Liquid penetrant testing solutions are capable of finding surface-breaking discontinuities on relatively smooth, nonporous surfaces.
This technique is based on the properties of liquid capillary action and surface wetting, which cause the liquid to rise when confined to a small opening. It is one of the more sensitive NDT testing methods for detecting surface flaws and is effective on unique shapes. Additionally, its relatively low resource requirement, and effectiveness on large inspection areas, and compatibility with a wide range of materials render it as a cost-effective option for a wide range of use cases.
A number of different liquid penetrant inspection systems are used in the industry today and offered by Signature Blasting Services. Fluorescent liquid penetrants are generally used when maximum flaw sensitivity is required. However, these penetrants must be observed under darkened conditions using an ultraviolet light source, which not always be practical in-situ. Some of the other more commonly used liquid penetrant techniques involve solvent removable or water washable red dye systems (visible contrast).
These techniques typically are comprised of three components – a cleaning fluid, the dye penetrant, and the developer. These systems, regardless of type, are often used to check weld integrity as part of quality control or to find defects in rolled, cast, or forged parts.