Welding Inspectors are employed to

Welding Inspectors are employed to assist with the quality control (QC)
activities that are necessary to ensure that welded items will meet specified
requirements and be fit for their application.
For employers to have confidence in their work, Welding Inspectors need to
have the ability to understand/interpret the various QC procedures and also
have sound knowledge of welding technology.
Visual inspection is one of the non–destructive examination (NDE)
disciplines and for some applications may be the only form.
For more demanding service conditions, visual inspection is usually followed
by one or more of the other non-destructive testing (NDT) techniques –
surface crack detection and volumetric inspection of butt welds.
Application Standards/Codes usually specify (or refer to other standards)
that give the acceptance criteria for weld inspection and may be very
specific about the particular techniques to be used for surface crack
detection and volumetric inspection, they do not usually give any guidance
about basic requirements for visual inspection.
Guidance and basic requirements for visual inspection are given by