Austenitic, Nickel, and Other Coarse Grain Alloy
Overview
Austenitic, Nickel, and Other Coarse-Grained Alloys
Corrosion Resistant and Cladded Materials
Austenitic and nickel-based alloy weld metals and other coarse-grained anisotropic materials affect ultrasound propagation causing beam distortion, beam scatter, mode conversions, and significantly increased attenuation resulting in a poor signal-to-noise ratio (SNR) as compared to shear wave inspections in low-alloy carbon steels. Inspection of these materials requires the use of dual phased array probes with RL (refracted longitudinal) wedge designs that acoustically insulate the transmitter and receiver beams for improved defect SNR and elimination of wedge echoes. Our Dual Linear Array™ (DLA) and Dual Matrix Array™ (DMA) probes are used with removeable wedges to combine different inspection techniques, such as direct L-wave, creeping wave, RTT (round trip tandem), and other multi-mode techniques, into a single phased array S-scan image for full volumetric weld inspection. |  |
Dual Array Probes (DMA/DLA)
Dual array probes consist of two phased array probes wired to the same connector. They can be either matrix or linear arrays. One probe performs a sectorial scan and the echoes coming back from the defect are captured using the second probe.
A25 |
A27 |
A26 |
A36 | |
| Frequency | 5 MHz | 4 MHz | 2.25 and 4 MHz | 2.25 and 4 MHz |
|---|---|---|---|---|
| Configuration | Dual 16 (Linear) | Dual 32 (16 × 2 Matrix) | Dual 32 (Linear) | Dual 64 (Linear) |
| Aperture | 12 mm × 5 mm | 16 mm × 6 mm | 32 mm × 12 mm | 64 mm × 12 mm |
| Recommended Wedge Series | SA25-DN70L-IH | SA27-DN55L-FD15-IHC | SA26-DN55L-FD40-IHC | SA36-DN55L-FD200-IHC |
| Characteristics | Compatible with the COBRA™ scanner for the inspection of small-diameter pipes (<10 mm thick) | General purpose with excellent overall performance and near-surface resolution (10 mm–40 mm thick) | Optimized for very thick materials (40 mm–80 mm) | Optimized for extra thick materials (>80 mm) |
| Minimum Instrumentation Requirement |
16:64PR (one probe)
32:128PR (two probes) | 32:128PR (two probes) | 32:128PR (two probes) | 64:128PR (one probe) |
Dual UT (TRL) A27 ProbesDual conventional UT probes can be used for surface wave inspection or, in conjunction with DMA probes, for full weld coverage. The detachable wedges enable more versatility for different pipe diameters and stability. |
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Onboard DMA and DLA Creation and Beam Setup
The OmniScan™ X3 enables you to create custom Dual Linear Array (DLA) or Dual Matrix Array (DMA) probes and wedges. In addition to creating phased array (PA) focal laws, you can also use the scan plan to set up total focusing method (TFM) and phase coherence imaging (PCI) groups. The scan plan accommodates a wide range of geometries, including COD configurations. |
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General Techniques
Ultrasonic Weld Inspection Solutions
The OmniScan flaw detector has an established track record for reliable and cost-effective phased array (PA) weld inspections as an alternative to radiography. Olympus ultrasonic weld inspection solutions provide an affordable means to inspect welds in compliance with major code and manufacturing requirements. An ideal combination of acquisition unit, scanner, encoder, and software, these solutions can be put to work virtually anywhere. Continuously improved and supported software makes the inspection of welds even easier, allowing you to complete your entire workflow more efficiently.
The Olympus weld inspection solutions applies to welds made of carbon steel or corrosion resistant alloy such as austenitic.
General Benefits:
- Fast weld inspection of different diameters, thickness, and materials
- 100% volumetric weld coverage
- Adaptable to butt welds, circumferential welds, long seams, one-sided access configuration, and most common weld profiles
- Portable for in-house and field inspections
Combining Different Techniques for Full Weld Coverage and Improved Efficiency
Phased Array Pulse-Echo Technique Phased array technique is based on the capacity to electronically modify ultrasonic beams generated by probes that contain multiple small elements. When these elements are excited using different time delays (focal laws), the beams are steered at different angles and focused at specific depths. |  |
Conventional UT Pulse-Echo Technique This technique uses a single element transducer to generate an acoustic beam at a fixed angle. The echo coming back to the transducer is interpreted by the instrument to provide information on size and position. |  |
| Time-of-Flight Diffraction (TOFD) Technique Time-of-flight diffraction (TOFD) is an ultrasonic technique that relies on the property of defects such as cracks to diffract energy from their tips to the receiver probe when impinged by ultrasonic beams generated by the transmitter probe. TOFD technique uses a wide beam that provides good coverage and is independent of defect orientation. |  |
Transmit-Receive Longitudinal Wave (TRL) This technique uses separate transmit and receive probes to generate refracted longitudinal wave. The use of separate probes minimizes vulnerability to noisy material, which is especially beneficial for inspection of coarse grain alloy, such as austenitic and nickel. |  |
Surface Wave Technique The surface wave (creeping) technique is an ultrasonic test in which discontinuities are detected by the return of a creeping wave that tracks the surface of the component being tested. |  |
Ultrasonic Testing (AUT) in Lieu of Radiography Testing (RT)
Ultrasonic testing in lieu of radiography has proven very effective for pressure vessels, tanks, piping, and other weld configurations. Olympus ultrasonic weld inspection solutions features comply with ASME, API and other radiography replacement code requirements such as full raw data collection and the use of an encoder. Compared to conventional radiography, Olympus ultrasonic weld inspection solutions offer multiple benefits such as:
- No radiation safety hazards
- Eliminates work area disruption
- Real time digital archiving of inspection data
- Elimination of film archiving
- Improved productivity
- Improved probability of detection (POD)
Comparing the Indications
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Measurement Capabilities
| ID | Type of Defect | Ultrasound (AUT) | Radiography (RT) |
| 1 | Toe crack |
• Position X, Y, and Z
• Length sizing • Height sizing |
• Position X and Y
• Length sizing |
| 2 | Centerline crack |
• Position X, Y, and Z
• Length sizing • Height sizing | • No detection |
| 3 | Porosity |
• Position X, Y, and Z
• Length sizing |
• Position X and Y
• Length sizing |
| 4 | Incomplete root penetration |
• Position X, Y, and Z
• Length sizing • Height sizing |
• Position X and Y
• Length sizing |
Benefits of the Olympus Ultrasonic Weld Inspection Solutions
| Olympus Ultrasonic Solutions | Radiography (RT) | |
| Absence of Radiation hazard | Yes | No |
| Absence of restricted area | Yes | No |
| Ease of deployment on site | Yes | No |
|
Probability of detection (POD)
(Planar defects such as crack and lack of fusion) | Very good | Poor |
| Inspection throughput | Very good | Good |
| Depth sizing capability | High accuracy | Poor |
| Length sizing capability | High accuracy |
Good accuracy
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