Ultrasonic testing (UT) remains the most accurate non-destructive testing (NDT) method for measuring remaining wall thickness and quantifying corrosion depth. This data feeds directly into integrity management systems, allowing engineers to assess fitness-for-service and plan maintenance before problems and issues escalate.
Conventional UT, however, has real limitations. Spot readings at thickness measurement locations (TML) provide useful trend data, but they can’t guarantee full area coverage. Corrosion doesn’t follow patterns. It develops anywhere, in many morphologies, and industry experience consistently shows that point-by-point UT misses defects.
Phased Array Ultrasonic Testing (PAUT) changes that equation. With 100% area coverage, high-resolution data, and software tools that support automatic defect recognition, PAUT-based corrosion mapping gives engineers a complete picture of asset condition.
Eddyfi Technologies offers a scalable range of corrosion mapping solutions, from semi-automated to fully automated systems, designed to match inspection environment, asset type and geometry, and productivity requirements.
What is Phased Array Corrosion Mapping?
Phased array corrosion mapping (PACM) is an ultrasonic inspection method that uses a multi-element probe to electronically steer and focus sound beams across a surface. Unlike single-element UT, which records thickness at individual spot locations, phased array corrosion mapping collects data across the full area of a component in a single encoded scan.
The result is a high-resolution C-scan image (top view) showing wall thickness variation across the entire inspected surface, typically at 1x1mm resolution. This allows engineers to:
- Identify the location, extent, and depth of corrosion
- Calculate corrosion rates more accurately
- Prioritize remedial maintenance with confidence
- Demonstrate regulatory compliance with fully auditable data sets
PACM is applicable to pressure vessels, pipelines, storage tanks, ship hulls, and any asset where wall loss from corrosion or erosion is a concern.
Semi-Automated vs. Automated: Which to Choose?
The right approach depends on asset size, access conditions, and required coverage.
Semi-automated scanners are manually operated but fully encoded. They are portable, cost-effective, and ideal for targeted inspections on pipework, vessels, and areas with restricted access. One person can operate them. Data is fully recordable.
Automated crawlers are robotic systems with pre-set scanning sequences. They remove the manual requirement entirely and are the preferred choice for large assets, storage tanks, large pressure vessels, ship hulls, where coverage speed and consistency are critical.
Both approaches support PAUT and deliver auditable, high-resolution data sets.
PaintBrush™ 2: The Semi-Automated Benchmark
The PaintBrush™ 2 sets the market standard for semi-automated corrosion mapping. It’s a patent-protected, agile scanner that handles both flat and curved surfaces with 100% area coverage and no grid constraints.
Key characteristics:
- Operating temperature up to 150°C / 302°F
- Broad probe compatibility
- Intuitive one-person operation
- Freedom to scan without predefined grid patterns
Paired with the Cypher® instrument, it is the recommended solution for pipework, pressure vessels, dome ends, and confined-access areas.
NDT Sweeper: Compact Encoded Scanning
The NDT Sweeper is a handheld encoded scanner for operators who need maximum flexibility in tight or hard-to-reach areas.
Key characteristics:
- Covers 100mm (4 in) OD to flat plate
- Both axes encoded — no index line required
- Lightweight ergonomic design
- Suitable for carbon steel and composite components
The Sweeper is the right tool when a full automated deployment isn’t practical. It reduces setup time, eliminates manual marking, and still produces fully recordable encoded data.
Automated Corrosion Mapping
For large-scale assets, Eddyfi Technologies’ automated inspection scanners deliver the coverage and throughput that manual scanning cannot match.
Battery-operated and remotely controlled, available in magnetic (ferrous) and non-magnetic (non-ferrous) configurations:
- 1mm (0.04 in) resolution PAUT corrosion mapping
- High-speed scans: 1m x 0.6m area in 90 seconds
- Aqualock™ waterbox technology for consistent coupling
- Raster arms from 300mm to 1,160mm
- Compatible with PAUT, conventional UT, and TOFD probes
- Up to 9:1 cost savings versus traditional internal visual inspection
These systems are designed for Non-Intrusive Inspection (NII) campaigns where shutdown avoidance is required.
Panther™ 2: High-Throughput Automated Inspection
For production environments and integrators where throughput and technique flexibility are non-negotiable, Panther™ 2 is the instrument of choice.
- Fastest TFM data throughput commercially available
- 32 to 2,048 element configurations, scalable via daisy chain
- 320 MB/s data link (USB3 or RJ45)
- “Flash” mode: up to 10x faster than conventional PAUT instruments
- Open SDK for custom application development
- Compatible with Acquire, Capture, and CIVA software
Cypher®: The Instrument at the Core
Cypher® is Eddyfi Technologies’ most advanced portable PAUT instrument and the primary acquisition platform for semi-automated corrosion mapping solutions.
- 64:128 phased array configuration
- 4x faster TFM than competing portable instruments
- Guided setup with automated probe detection
- IP65 certified, MIL-STD-810G drop-tested
- 12.1-inch sunlight-readable touchscreen
Cypher® reduces setup time, minimizes operator error, and produces consistent data regardless of technician experience level,a significant advantage when inspection teams face skills shortages.
Authors: Stuart Kenny, Gareth Mugford