What is Visual Testing ?
PRINCIPLE
Visual testing is done at the beginning, during and at end of fabrication of the part. This can include welding, casting forging. In case of welding, visual testing is done from weld preparation, application of the welding procedure specification (WPS) to the final weld. Welding inspector must therefore have knowledge of the fabrication steps to the final product. Visual testing requires the inspector to have in depth knowledge of the manufacturing process and the flaws that can be expected with such processes. In case of welding that would mean all welding methods. Visual inspector must have a thorough knowledge of the applicable codes for acceptance/rejection of discontinuities.
There are many other areas where visual testing is performed. Visual testing for service induced damage can include corrosion, pumps, valves etc.
Visual testing is also done on consumer goods and automobiles. This is done by machine vision
EQUIPMENT
Magnifying glass, flash light, measurement gauges
APPLICATIONS
Visual testing has a range of applications that include inspection of welding, castings, forgings, composites, coatings etc. Welding inspection includes checking for bevel preparation, proper fit-up prior to welding, misalignment, final weld profile, weld discontinuities such as slag, porosity, undercut, cracks etc. Composite inspections looks for deformities, matrix cracking, impact damage, blistering.
INDUSTRY CODES
- AWS D1.1 for structural weld inspections. See Table 8.1
- ASME VIII, Div 1 for pressure vessels
- ASME codes various
TRAINING
- VT Level II
- Duration – 24 hours