An industrial pressure vessel is being fabricated, and a critical full penetration groove weld needs to be inspected. Due to the thickness of the material (25 mm steel) and the requirement to detect subsurface flaws like porosity, slag inclusions, and lack of penetration throughout the weld, which Non-Destructive Testing (NDT) method would be most appropriate and reliable for this application?

Question: An industrial pressure vessel is being fabricated, and a critical full penetration groove weld needs to be inspected. Due to the thickness of the material (25 mm steel) and the requirement to detect subsurface flaws like porosity, slag inclusions, and lack of penetration throughout the weld, which Non-Destructive Testing (NDT) method would be most appropriate and reliable for this application?

Answer options:

• Liquid Penetrant Testing (PT)
• Magnetic Particle Testing (MT) ✅ Radiographic Testing (RT)
• Visual Testing (VT)

Correct answer: Radiographic Testing (RT)

Explanation: Radiographic Testing (RT) uses X-rays or gamma rays to produce an image of the internal structure of a material, making it highly effective for detecting subsurface flaws such as porosity, slag inclusions, and incomplete penetration in thick materials. Liquid Penetrant Testing and Magnetic Particle Testing are primarily used for surface and near-surface defects, while Visual Testing only identifies surface imperfections.