1 Where UT is specified, the following requirements shall be met:
• The area adjacent to the weld (equivalent to the full skip distance of the maximum probe angle used) shall be scanned by a compression wave probe to check for lamellar flaws prior to scanning the weld itself
• For butt welds, examination of the weld for axial flaws shall be performed utilizing at least two different angle beam, shear wave probes. The weld shall be scanned from both sides and on the inside and outside surfaces, where access permits, to ensure complete coverage of the weld volume
• For butt welds, examination of the weld for transverse flaws shall be performed utilizing at least two different angle beam, shear wave probes. The probe angles shall be chosen to cover the full weld throat thickness. The weld shall be scanned from both sides, essentially parallel to the weld axis. For weld throat thicknesses greater than 2.0 in (50mm), the weld cap shall be dressed flat and flush with the parent material and the scan performed along the weld axis
• For set-on or set-in branch welds, examination of the weld shall be performed utilizing a combination of at least two different angle beam, shear wave probes and a compression wave probe. The weld shall be scanned from the inside and outside surface of the shell and from the outside surface and internal bore of the nozzle
• Calibration block shall be of sufficient length to permit a minimum of four signal responses from the artificial reflectors to be used to construct the DAC curve for all probe angles
• The use of tandem probes, enhanced UT techniques, such as Timeof-Flight-Diffraction (TOFD) or mechanized pulse echo equipment