<![CDATA[The integrity of Dissimilar Metal Welded (DMW) joints in Corrosion Resistant Alloy (CRA) clad pipes is critical for offshore infrastructure. However, the highly anisotropic, coarse-grained dendritic structure of austenitic Inconel 625 overlays causes severe acoustic attenuation and scattering, rendering conventional shear wave testing ineffective. This study evaluates a Manual Ultrasonic Testing (MUT) methodology utilizing 4 MHz focused longitudinal waves and dual-element (TRL) probes to penetrate these metallurgical boundaries. A 28-inch API 5L X65/Inconel 625 clad pipe mockup (60.57 mm total thickness) featuring 9 fabricated discontinuities (EDM notches and volumetric targets) was inspected and cross-validated against Radiographic Testing (RT). MUT achieved a 100% detection rate, correctly sizing internal flaws such as Flaw 7 (cluster porosity: 2–7 mm depth, 21 mm length, 3 mm height), which RT (88.9% detection rate) failed to identify due to geometric thickness limitations and 2D projection constraints. The optimized MUT configuration consistently achieved a Signal-to-Noise Ratio (SNR) ≥ 3:1 (≥ 6 dB), with structural noise floor levels maintained between 13% and 30% of Full Screen Height (FSH). By providing precise 3D spatial localization and vertical height profiling capabilities absent in RT. This study validates that the proposed MUT methodology satisfies the strict compliance criteria of DNVGL-ST-F101 and ASME Section V.]]>
Copyrights © 2026
