Phased Array Ultrasonic Testing Services
Phased Array Ultrasonic Testing, commonly known as PAUT, is an advanced nondestructive testing method used to examine welds, pipes, pressure vessels and other industrial components without damaging them.
Unlike conventional ultrasonic testing, which normally uses a single ultrasonic element, a phased array probe contains multiple independently controlled elements. By adjusting the timing of the pulses sent to these elements, the ultrasonic beam can be electronically steered, focused and swept through a selected range of angles.
This allows inspectors to examine a larger volume of material from a single probe position and produce detailed cross-sectional images of the inspected component.
How Does PAUT Work?
A PAUT system controls multiple probe elements using precisely timed electrical pulses. These elements generate ultrasonic waves that enter the component through a suitable wedge or coupling arrangement.
The system can create:
➤ Sectorial scans covering several refracted angles
➤ Linear scans covering a defined inspection area
➤ Focused beams at selected depths
➤ Encoded scans linked to the probe position
➤ A-scan, S-scan, B-scan and C-scan presentations
The resulting data helps qualified personnel detect, locate, characterize and size discontinuities within the weld or parent material.
Beam steering and electronic focusing are the main advantages of phased array technology over conventional single-element ultrasonic testing. Evident Scientific’s PAUT overview provides further technical background.
Defects Detectable Using PAUT
Subject to the component, material, inspection surface and approved procedure, PAUT can detect discontinuities such as:
➤ Lack of fusion
➤ Lack of penetration
➤ Cracks
➤ Slag inclusions
➤ Porosity
➤ Incomplete root penetration
➤ Undercut and root profile indications
➤ Lamination
➤ Corrosion and wall-thickness loss
➤ Hydrogen-related or service-induced cracking
➤ Manufacturing defects in forgings and components
PAUT is particularly effective for detecting planar discontinuities when the inspection technique directs the ultrasonic beam appropriately toward the expected defect orientation.
Major Applications
PAUT can be used for manufacturing, pre-service and in-service inspection of:
➤ Process piping
➤ Pipeline girth welds
➤ Pressure vessels
➤ Storage tanks
➤ Boilers and heat exchangers
➤ Structural welds
➤ Nozzle and branch connections
➤ Flanges and complex weld geometries
➤ Offshore and marine structures
➤ Castings and forgings
➤ Corrosion mapping areas
➤ Power-generation components
Advantages of PAUT Inspection
Improved Inspection Coverage
Multiple angles can be generated from a single probe position. This helps cover the weld volume and heat-affected zone efficiently.
Accurate Defect Location
PAUT data can indicate the position of a discontinuity relative to the weld centreline, inspection surface and component thickness.
Enhanced Imaging
Sectorial and encoded scan views make the inspection data easier to interpret and review compared with a conventional single A-scan presentation.
Permanent Data Recording
Encoded PAUT inspections create digital records that can be stored, reviewed and audited after completing the examination.
Faster Inspection
Electronic beam steering can reduce probe movement and improve inspection productivity, particularly when appropriate scanners and encoded systems are used.
No Ionising Radiation
PAUT does not use ionising radiation. Therefore, it avoids many of the safety restrictions and operational interruptions associated with radiographic testing.
Defect Sizing Capability
When supported by a properly qualified procedure and suitable sizing technique, PAUT can assist in evaluating discontinuity length and through-wall height.
PAUT Inspection Procedure
A typical PAUT weld inspection involves:
1. Reviewing the applicable drawing, weld geometry, material and acceptance criteria.
2. Selecting the probe, wedge, frequency and focal-law configuration.
3. Preparing a scan plan to demonstrate coverage of the weld and heat-affected zone.
4. Calibrating the equipment using a suitable reference or calibration block.
5. Confirming surface condition and scanning access.
6. Performing manual or encoded data acquisition.
7. Analysing and evaluating recorded indications.
8. Preparing a detailed inspection report with scan images and results.
Inspection parameters must be selected according to the component geometry and applicable code. A standard setup should not automatically be applied to every weld configuration.
PAUT Standards and Codes
Depending on the project and client requirements, PAUT inspection may be performed with reference to applicable standards and construction codes such as:
➤ ASME Boiler and Pressure Vessel Code, Section V
➤ ISO 13588 for phased array testing of welded joints
➤ ISO 20601 for automated phased array testing of thin-walled steel components
➤ ISO 4761 for PAUT acceptance levels
➤ ISO 22825 for ultrasonic testing of austenitic and nickel-alloy welds
➤ ISO 23864 for automated total focusing and related ultrasonic technologies
➤ API 1104, where contractually applicable to pipeline weld inspection
➤ Project-specific specifications and approved written procedures
ISO identifies ISO 13588:2019 as covering semi- or fully automated PAUT of fusion-welded joints, including relevant capabilities and limitations. ISO 13588 information
The applicable edition, acceptance criteria and qualification requirements must always be confirmed from the client’s construction code and project specification.
Limitations of PAUT
PAUT is an advanced method, but its effectiveness depends on proper planning and execution. Potential limitations include:
➤ Restricted scanning access
➤ Rough or irregular inspection surfaces
➤ Coarse-grained or highly attenuative materials
➤ Complex weld geometries
➤ Unfavourable defect orientation
➤ Inaccurate component dimensions
➤ Unsuitable probe or wedge selection
➤ Inadequate calibration blocks
➤ Poor coupling conditions
➤ Insufficient operator experience
A scan plan, representative calibration block and procedure demonstration may be required before accepting a technique for critical or complex components.
PAUT Inspection Deliverables
Depending on the agreed scope, the final documentation may include:
➤ Approved PAUT procedure
➤ Inspection and test plan
➤ Technique sheet
➤ Weld-specific scan plan
➤ Equipment and calibration details
➤ Calibration-block details
➤ Inspection coverage information
➤ Encoded PAUT data
➤ Indication evaluation table
➤ Scan images
➤ Weld-wise inspection report
➤ Final inspection summary
Our PAUT Inspection Capabilities
Integrity & Advanced Inspection Solutions India Private Limited provides PAUT inspection support for pipelines, piping welds, pressure vessels, structural components, power plants, petrochemical facilities, refineries, marine installations and shutdown projects.
Our services can be arranged with:
➤ Qualified PAUT personnel
➤ Advanced PAUT equipment
➤ Suitable probes, wedges and scanners
➤ Customized calibration blocks
➤ Manual and encoded inspection configurations
➤ PAUT and TOFD combined inspection
➤ On-site analysis and reporting
➤ Project-specific procedure preparation
➤ Domestic and international project mobilization
Request a PAUT Inspection Proposal
Please share the following information for technical and commercial evaluation:
➤ Component or weld type
➤ Material specification
➤ Outside diameter and thickness
➤ Weld joint configuration
➤ Total number or length of welds
➤ Applicable code and acceptance criteria
➤ Site location
➤ Expected inspection schedule
➤ Drawings or weld details
➤ Required reporting format
Call to Action:
Contact our technical team for PAUT feasibility assessment, inspection planning and a techno-commercial proposal.