Visual Testing (VT)

Visual Inspection involves the visual observation of the surface of a test object to evaluate the presence of surface discontinuities such as corrosion, misalignment of parts, physical damage and cracks. Visual testing can be done by looking at the test piece directly, or by using optical instruments such as magnifying glasses, mirrors, borescopes, and computer-assisted viewing systems. This is arguably the oldest and most widely used NDT method. VT can be applied to inspect castings, forgings, machined components, and welds. Industries utilizing this service include Fabrication, Construction, Automotive, Power Generation and Transportation. These inspections are performed to meet IS, BS, ASTM, AWS, ASME (American Society for Mechanical Engineers) and many other standards.

Advantages of VT

Limitations of VT

  • Low cost
  • Portable equipment (if any)
  • Immediate results
  • Minimum special skills required
  • Minimum part preparation
  • Only suitable for surfaces than can be viewed
  • Usually only larger defects can be detected
  • Scratches can be misinterpreted for cracks
  • Quality of inspection influenced by surface condition, physical conditions, environmental factors and physiological factors