List four NDE methods commonly referenced in welding standards and typical purpose.

• A. Visual inspection (VT) for surface defects, Radiography (RT) for internal flaws, Magnetic Particle (MT) for surface and near-surface defects, Liquid Penetrant (PT) for surface-breaking defects.
• B. Ultrasonic testing only.
• C. Magnetic resonance imaging for all welds.
• D. Dye marking for aesthetics only.

Answer: (A)

The main concept here is knowing the Non-Destructive Examination methods commonly called out in welding standards and what each method detects. Visual inspection checks the weld’s surface appearance and geometry, spotting surface defects and issues like cracks, undercut, misalignment, or porosity visible on the surface. Radiography uses penetrating radiation to look inside the weld and surrounding metal, revealing internal flaws such as porosity, slag inclusions, lack of fusion, or subsurface cracks that aren’t visible from the outside. Magnetic Particle testing magnetizes the metal and applies magnetic particles to reveal discontinuities at or near the surface in ferromagnetic materials, making surface-breaking or near-surface cracks and flaws easier to locate. Liquid Penetrant testing relies on a penetrant liquid seeping into any surface-breaking defect; after applying a developer, the defect becomes visible, highlighting cracks and other flaws open to the surface. Together, these four cover surface conditions, near-surface issues, and internal defects that welding standards aim to detect.

Other options don’t fit because ultrasonic testing, while used in many contexts, is not listed here as one of the four most commonly referenced methods in this context; magnetic resonance imaging isn’t a welding NDE technique; and dye marking is not a defect-detection method but a cosmetic or marking process, not an NDE assessment.