Welding Inspection, Welding Inspectors are an essential part of the welding industry.
Non Destructive Welding Evaluation and Testing (X-ray, Ultrasound, Eddy Current, Visual, Dye Penetrant) are part of Welding Inspection.
There are numerous suppliers who provide this service.
CWI or Certified Welding Inspectors are trained in Codes, NDE, NDT methods. Useful Links:

AWS, Base Line Data , Tulsa Welding School , TWI Welding Institute, CSWIP , Weld Test , XRay Welding,
Vidisco Shipyard X Ray , Welding Inspectors, Material Inspection , Hobart Institute , Milwaukee Technical College,
WTTI , Lincoln Tech , Singapore Welding Society , UT Scan Ultrasonic , GE, Baker Testing , Trikon, ESAB