ASNT NDT III ET case studies
ASNT NDT III ET · Put your knowledge to work in context.
The ASNT NDT Level III certification in Electromagnetic Testing (ET) is an advanced, method-specific credential offered through ASNT's NDT certification program, which ASNT describes as comprehensive, two-part certifications recognized internationally as validation of competence. Candidates sit an NDT General computer-based exam plus specific computer-based exams for one or more methods; the ET exam is the method-specific portion for electromagnetic testing. The ASNT NDT III ET case studies are 5 cases and about 2,594 words.
1Eddy Current Inspection of Heat Exchanger Tubes After a Re-Tube
You are the Level III for a refinery that just re-tubed the shell side of a fixed-tube-sheet carbon steel heat exchanger with 19.05 mm OD, 1.65 mm wall, seamless 90/10 Cu-Ni tubes (conductivity ~6.5 %IACS, relative permeability 1.0). The bundle has 412 tubes, and the client wants a baseline eddy current inspection before hydrotest.
654 words, about 3 min2Phase Analysis Discrepancy on a Stainless Steel Tubing String
A power plant condenser has 304 stainless steel tubes (19.05 mm OD, 1.24 mm wall, conductivity ~1.4 %IACS, relative permeability 1.0). Your Level II technician ran a 300 kHz absolute bobbin coil and flagged 14 tubes with indications in the support-plate regions, calling them 'OD pitting at 30-40 % wall loss.' The client is preparing to plug those tubes.
572 words, about 3 min3Magnetic Flux Leakage vs. Eddy Current for a Ferromagnetic Storage Tank Floor
A terminal operator asks you to select a method for inspecting the floor of an above-ground storage tank. The floor plates are 6 mm carbon steel (relative permeability ~200-500, conductivity ~7 %IACS).
593 words, about 3 min4Probe Selection and Lift-Off Compensation on a Welded Aluminum Structure
You are asked to inspect a 2024-T3 aluminum aircraft skin (conductivity ~30 %IACS, relative permeability 1.0, 2.0 mm thick) for fatigue cracks emanating from fastener holes. The skin is coated with a 50 µm primer, and the fasteners are installed.
376 words, about 2 min5Frequency Choice and Phase Reference for a Thin-Wall Titanium Tube
A chemical plant has titanium Grade 2 tubes (12.7 mm OD, 0.9 mm wall, conductivity ~2.4 %IACS, relative permeability 1.0). The client wants detection of 10 % wall loss on both ID and OD surfaces.
399 words, about 2 min