Which NDT method is primarily used to assess weld geometry and surface finish?

• A. Ultrasonic Testing
• B. Magnetic Particle Testing
• C. Liquid Penetrant Testing
• D. Visual Inspection

Answer: (D)

Visual inspection directly observes the weld’s shape, size, and surface condition, making it the most effective way to judge geometry and finish. Inspectors assess features like weld width, leg length, throat thickness, root opening, and reinforcement, as well as surface quality, alignment, and any visible irregularities. This hands-on, surface-focused check is done with good lighting and simple tools such as weld gauges and profiles, which is exactly what geometry and finish evaluations require.

Other NDT methods shine at different tasks: ultrasonic testing looks for internal flaws and can measure thickness, not the weld’s visible shape; magnetic particle testing reveals surface or near-surface discontinuities in ferromagnetic materials but doesn’t reliably convey geometry or finish; liquid penetrant testing detects surface-breaking defects but doesn’t provide a full view of weld geometry or smoothness. Hence, for assessing weld geometry and surface finish, visual inspection is the best fit.