ASME第8卷-1是这样描述的
UW-52 SPOT EXAMINATION OF WELDED JOINTS
NOTE: Spot radiographing of a welded joint is recognized as an effective
inspection tool. The spot radiography rules are also considered to
be an aid to quality control. Spot radiographs made directly after a
welder or an operator has completed a unit of weld proves that the
work is or is not being done in accordance with a satisfactory procedure.
If the work is unsatisfactory, corrective steps can then be taken
to improve the welding in the subsequent units, which unquestionably
will improve the weld quality.
Spot radiography in accordance with these rules will not ensure a
fabrication product of predetermined quality level throughout. It
must be realized that an accepted vessel under these spot radiography
rules may still contain defects which might be disclosed on
further examination. If all radiographically disclosed weld defects
must be eliminated from a vessel, then 100% radiography must be
employed.