Advanced NDT

Advanced NDT solutions

MISTRAS utilises combinations of advanced technology to define solutions led approaches to solve our clients inspection challenges
MISTRAS offers a wide range of advanced NDT technologies from our UK operation. With in-house level 3 experts, dedicated PhD level research and applications engineers and time served technicians, we continue to develop technology led solutions based upon our clients needs. We are able to advise clients in technical outcomes such as probability of detection, accuracy, productivity as well as commercial factors to ensure best value result.
  • Automated Ultrasonic Inspection/Testing (B, C, D-scan, HIC/SWC inspection and corrosion mapping)
  • Phased Array Ultrasonic Testing
  • Shear Wave Ultrasonic Testing
  • Time of Flight Diffraction (TOFD)
  • AUBT and velocity ratio measurements (HTHA Inspection)
  • Pulsed Eddy Current Testing (PECT)
  • Computed and Digital Radiography
  • Long Range Ultrasonic Testing (GUL)
  • Guided Bulk Wave (GBW)
  • Eddy Current Array (ECA)
  • Acoustic Emission
  • Touch Point Corrosion (TPC)
  • EMAT
  • MFL Floor Scanning
  • Advanced Tube Inspection Technologies
  • Impact Echo (IE)

Please see our Advanced NDT services below

AUTOMATED ULTRASONIC TESTING SERVICES
Automated Ultrasonic inspection offers many benefits to our client base and is utilised on capital projects, maintenance inspection, turnaround scheduling/planning and shutdown/turnaround/ outage situations. From high speed erosion/corrosion scanning systems using computer controlled ultrasonic scanners and software designed by our in house software engineers, highly sensitive P-Scan systems for accurate identification, location and sizing of defects in weld material and “on-line” inspection of various assets for prioritisation in turnaround schedules, phased array ultrasonic inspection used for weld inspection in lieu of radiography and a variety of other applications, to high speed Time of flight Diffraction, MISTRAS Services provides the appropriate ultrasonic inspection solution to your site. Some of the factors that we consider when recommending the appropriate ultrasonic technology are: the anticipated damage mechanism, operating condition of the asset, ability to access the area in question and the proximity of trade involvement to the inspection area. Automated Ultrasonic Testing allows our clients to accurately monitor discontinuities over successive inspection intervals, calculate growth rates of discontinuities and plan repair or replacement activities. In addition, AUT supplies highly accurate data as an important tool for implementing Risk Based Inspection Programs, Fitness for Service Analysis and remaining useful life programs.

Benefits of AUT:

  • Optimises your inspection spend
  • Reliable, repeatable and accurate
  • Minimizes costly internal entry
  • Minimizes unnecessary repairs
  • Reduces or eliminates downtime
  • Reduces outage
  • Reduces turnaround schedules
  • “On-Line” inspection provides data for advanced planning
  • Accepted by regulatory and industry standards and specifications
  • Supports RBI, FFS and remaining life programs
ALTERNATING CURRENT FIELD MEASUREMENT (ACFM)

ACFM or Alternating Current Field Measurement is used in order to identify and size surface breaking cracks in metal components. This electromagnetic technique has several benefits. ACFM may be utilized on coated materials. The coatings must be strictly adhered to the surface in order to perform the test successfully.

Also, the test can be performed if the surface contains minor scaling and debris which eliminates the need for pre-cleaning prior to inspection. Test indications can be sized to show depth and length of indications. Lastly, the test can be performed at elevated temperatures as high as 900° degrees Fahrenheit.

ACFM has been used extensively in off shore platform applications on piping and structural members. Process piping in Oil and Gas facilities have successfully utilized ACFM also. Bridges and large Cargo cranes have also benefited from the ability to rapidly inspect and size defects in the field using ACFM.

ACOUSTIC EMISSION (AE)

AE Monitoring Systems on Bridge
Acoustic Emission (AE) testing is a powerful method for examining the behavior of materials deforming under stress. Acoustic Emission may be defined as a transient elastic wave generated by the rapid release of energy within a material. Materials “talk” when they are in trouble: with Acoustic Emission equipment you can “listen” to the sounds of cracks growing, fibers breaking and many other modes of active damage in the stressed material. Small-scale damage is detectable long before failure, so AE can be used as a non-destructive technique to find defects during structural proof tests and plant operation. AE also offers unique capabilities for materials research and development in the laboratory. Finally, AE equipment is adaptable to many forms of production QC testing, including weld monitoring and leak detection.

Behaviour of materials:

  • Crack propagation
  • Yielding
  • Fatigue
  • Corrosion, Stress corrosion
  • Creep
  • Fibre fracture, de-lamination
DIGITAL RADIOGRAPHY

Digital Radiography is one of the newest forms of radiographic imaging. Since no film is required, digital radiographic images are captured using either special phosphor screens or flat panels containing micro-electronic sensors. Captured images can be digitally enhanced for increased detail and are easily archived. There are a number of forms of digital radiographic imaging including:

  • Computed Radiography (CR): Digital imaging process that uses a special imaging plate which employs storage phosphors.
  • Real-Time Radiography (RTR): A form of radiography that allows electronic images to be captured and viewed in real time.
  • Direct Radiography (DR): A form of real-time radiography that uses a special flat panel detector.
  • Computed Tomography (CT): Uses a real-time inspection system employing a sample positioning system and special software.

MISTRAS Services employs a wide array of digital radiographic systems to solve specific industrial problems. Thickness profiles of piping systems, both insulated and uninsulated, are performed using computed radiography, while large production runs of smaller parts are inspected using direct radiography. Real time radiography is utilized for large “real time” inspections of insulated piping systems looking for areas of pipe degradation.

EDDY CURRENT TESTING | Tube Inspection
weld eddy current testing

Eddy Current testing uses the principals of electromagnetism as the basis for conducting inspections. When alternating current is applied to a conductor a magnetic field develops in and around the conductor. When a second conductor is introduced into the magnetic field an induced current flow is created. Eddy currents are a type of induced current. In the case of eddy current inspection, eddy currents are created using a probe. Inside the probe is a length of electrical conductor which is fectromagnetic induction occurs and eddy currents are induced. These eddy currents flowing in the material generate their own “secondary” magnetic field that opposes the coil’s primary magnetic field. The strength of the generated currents, known as the standard depth of penetration vary depending on probe frequency, material conductivity and permeability. One of the major advantages of traditional eddy current inspection is the variety of inspections that can be performed. Some of these inspection types are:

Crack detection A primary use of eddy current inspection as cracks cause a disruption in the circular flow patterns of the eddy currents and weaken their strength.

Conductivity measurements Because of the sensitivity to changes in a material’s conductive properties and magnetic permeability, Eddy Current is an excellent tool for material Identification and Material Sorting.

Multi-frequency eddy current systems refer to equipment that can drive inspection coils at more than two frequencies. This type of instrumentation is used extensively for tubing inspection in Power Generation and the Oil and Gas industries. Major advantages of this inspection are the ability to increase inspection information collected from one probe pull, comparison of same discontinuity signal at different frequencies, mixing of frequencies that helps to reduce or eliminate sources of noise and improves detection, interpretation and sizing capabilities.

A critical component of any eddy current examination is the ability to calibrate the unit based on reference standards manufactured from the same or very similar material as the test specimen. In the case of tubing inspection an ASME tubing pit standard is required. The advantages of Eddy Current inspection are: Sensitive to small cracks and defects, detects surface and near surface defects, immediate results are available, equipment is portable, minimum part preparation is required, probes do not need to contact the part and the ability to inspection complex shapes and sizes of conductive materials.

The limitations of Eddy Current include: Only conductive materials can be inspected, skill and training required is more extensive than other techniques, surface finish and roughness may affect the test.


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