Non-destructive testing (NDT) is used to assess weld quality without damage. Which two methods are commonly used in welding inspection?

• A. Destructive testing and chemical analysis
• B. Radiographic testing and bending test
• C. Wet magnetic testing and scratch testing
• D. Visual testing (VT) and ultrasonic testing (UT)

Answer: (D)

NDT weld inspection relies on methods that reveal flaws without harming the part. Visual testing is the first line of inspection, which examines the weld bead for surface defects, misalignment, porosity visible on the surface, undercut, slag, and cleanliness. It’s quick, inexpensive, and required in most quality programs as the baseline check.

Ultrasonic testing then peers into the weld interior. By transmitting high-frequency sound waves and measuring their echoes, inspectors can detect internal discontinuities such as lack of fusion, porosity, cracks, and determine weld geometry and thickness. This technique provides information that surface inspection alone can’t, without damaging the weld.

Together, visual testing and ultrasonic testing cover both surface and internal quality checks in a practical, non-destructive way, which is why they’re commonly used in welding inspection.