Advanced UT Inspections


Phased Array

Uses Of Phased Array
  • Multi-Angled Weld Inspections
  • UT Inspection of Odd Geometries
  • HIC/SOHIC Verification
  • Conventional UT Methods
  • Unique UT Techniques
  • Flaw Sizing
  • Flange Face Corrosion Analysis

Introduction

Phased Array technology is one of the latest advances in ultrasonics. It provides many useful tools for refining and chemical industry inspection purposes. A row of elements are excited in precise timing patterns to produce certain desired effects, such as ultrasonic beam steering or focusing the beam. This allows the user the ability to inspect certain portions or volumes of the weld using many different beam angles and focal laws. The result may be viewed as A-scan, B-scan, C-scan, or as a S-Scan (Sector scan) image. This technique is also used in a single axis scan motion, which makes it faster than conventional manual scanning.

 

Phased Arrays

  • Phased Arrays use multiple elements in a single housing, excited at specific intervals to generate uniform wave fronts at specified angles.
  • Any UT technique for flaw detection and sizing can be applied using phased array probes.
  • Allows for high speed electronic scanning without moving parts.
  • Inspections at multiple angles using a single, electronically controlled probe.

Advantages

Phased Arrays are extremely useful when examining difficult geometries. The ability to focus the beam at different points allows for accurate detection and maximum resolution of defects. One transducer has the ability to perform several inspections at once. Phased Array inspections also include pipe and pressure vessel weld examinations, turbine disk blade root inspections, Raised face and Ring-Joint Flange inspections, as well as supplemental prove up techniques for HIC/SOHIC inspections.

  • Tandem scanning in one array for the inspection of vertical fusion faces in narrow gap welds.
  • Beam steering enables greater control and flexibility to inspect complex geometries such as shafts, threaded pins, railroad axle set, or complex geometry welds such as those found in multi-layered vessels.
  • Focusing the beam intensely is important when looking at highly stressed points of a component, e.g. turbine disks, weld root areas.
  • Multiple focus, varied angle, complex scans: automated pipeline inspections and aerospace components.

 

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Time Of Flight Diffraction

 

Uses of ToFD:
  • New and Existing Weld Examinations
  • Detection and Sizing of Weld Defects
  • Fast Inspection Times
  • Multiple Techniques for Different Thicknesses
  • Examination of Material 0.25" thru 6" thick.

Introduction

Time of Flight Diffraction (TOFD) was developed in the 1970’s as a more accurate way to size planar flaws (cracks) for the nuclear industry. Advances in technology have made TOFD an extremely accurate and reliable defect detection tool, which can be used to gain data quickly with a positive result.

 

 

Technology

Time of Flight Diffraction uses two ultrasonic transducers in a pitch-catch method to introduce ultrasonic waves into the test piece for inspection. The transducers produce three distinct waves with different characteristics, paths and velocities.

Both longitudinal (compression) waves and shear waves are produced, which spread and give full volumetric coverage of the test piece. There are two different longitudinal waves that are introduced into the material, each with a different sound path. The first L-wave travels between the transducers just under the surface of the material and is called the "Lateral wave". The second is angled at the back wall and skips to the receiving transducer in a full-V path. Depending on the thickness of the material, different angles can be used to achieve full volumetric coverage. From these L-waves, shear waves are formed and propagate through the volume of the material. When defects are present, diffracted energy from the edges or tips are reflected and picked up by the receiving transducer.

 

Applications

TOFD can be used on piping and vessel welds. It is a useful tool in finding defects during initial equipment production, as well as service induced defects that occur over time. Weld washout due to process, cracking in coke drum welds; general existing or new weld production defects as well as surface corrosion can be detected and measured using the TOFD technique. There is no need to raster the transducers, TOFD is preformed in a single parallel line scan which makes data collection fast. With good access without limitations, up to 300 linear feet of weld can be inspected a day using this technique and equipment.

 

 

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Automated Corrosion Mapping

Uses of AUT Inspection:

  • Piping System Integrity
  • Pressure Vessel Integrity
  • Erosion/Corrosion Examination
  • Clad dis-bond Inspection
  • Lamination Inspection
  • Hydrogen Damage - Blistering/StepWise Cracking Evaluation
  • Automated Weld Examination
  • Phased Array and Time of Flight Diffraction Techniques

Introduction

The AIS automated inspection system uses different components from several manufacturers to provide complete automated inspection capabilities. It applies the TOFD, Pulse Echo, Corrosion mapping, and Phased Array technology to non-destructively screen piping and vessels, such as those found in the refining and petrochemical industries. The user is provided with a true representation of the test material, which speeds the process of defect interpretation and reporting. All data is recorded in digital format and scans are exactly repeatable for long-term monitoring purposes.

 

 

Technology

Automated Ultrasonic inspection uses conventional and specialized transducers to introduce sound in the test materials. These transducers are mounted to automated robotic crawlers, which articulate to cover large areas of the vessel or piping surface. The data collected is then displayed in color in multiple A-Scan, B-Scan, C-Scan, and D-Scan images A-scan representation is the view in which the signal amplitude is shown as a vertical excursion from the horizontal sweep time trace. The B-scan and D-scan presentations are two-dimensional views of cross-sectional planes through the test object on different axis. This imaging is helpful in distinguishing mid-wall inclusions such as laminations and blistering, from back-wall discontinuities like erosion and corrosion. The C-scan image is a two-dimensional plan view of the object. Indication of depth is color coded to provide the image with qualities, which resemble a topographical map viewed from the inspecting surface.

 

 

Corrosion Mapping

Corrosion Mapping: Corrosion mapping is one of the more common inspections performed today. It provides reliable information about the remaining wall and ID geometries of equipment and piping to engineers and inspectors, who use the information to establish corrosion rates, equipment longevity, and maintenance and repair cycles. It also provides information on the material integrity, such as laminar defects and blistering, which may occur due to the migration of hydrogen through the material due to process. It is possible to scan up to 400 square feet of surface area per day with the automated system. All vessels and piping systems in the refining and petrochemical industry are subject to material degradation and automated corrosion scanning can help detect where problem areas exist or where they may possibly exist in the future. AUT scanning provides digital images, which can be regenerated or archived for future examination. AUT corrosion scans can be remapped to establish flaw extension over time, allowing Fitness for Service assessments.

 

 

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Pipeline Inspection

 

The TD Pipe-Runner is an Automated Ultrasonic Phased Array Pipeline Girth Weld Inspection System with both Phased Array and conventional multichannel capability. Developed in cooperation with major, well established NDE inspection companies around the world and in response to a more cost-effective instrument.

 

Click here to view our Pipeline Inspection brochure.

 

 

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