ASME BPVC 2023 Section V

instrument, creating A-scan information in real time and
generating images that are essentially stacked A-scans,
as opposed to FMC/TFM, which is non-beam-forming.
F-451.1 Typical Workflow Process. Figures
F-451.1-1 through F-451.1-4 illustrate the typical workflow
processes mentioned in F-450 and illustrate that
for PAUT the following is true:
a The delay law calculation is determined by the type
of image reconstruction sector scan, linear scan, etc. and
other parameters such as travel time to the focus point.
b The data acquisition method can be determined by
the type of focusing [typically the case of dynamic depth
focusing DDF, zone focusing, linear scan, or sectorial
scan].
c The active focusing necessitates that the focal laws
be generated prior to acquisition.
F-451.2 Advantages of TFM Synthetic Focusing.
The following are some of the advantages of TFM:
a Only one FMC data acquisition is enough to generate
the various images, even when the equipment processed
a different mode during acquisition or the FMC
data was stored such that the TFM processing software
could reconstruct several modes. Instead of only for that
mode, it is possible to apply various TFM processes to
stored FMC as well.
b An accurate model of the component can be generated
with FMC data, which improves the resolution, and is
a function of the array and wedge definition and of the position
of the grid. In addition, the ability to resolve component
and weld geometry in the reconstructed image has
advantages e.g., verification of equipment setup and less
ambiguous interpretation.
c The settings e.g., focal law calculations can be
completely disassociated from the acquisition. In the case
of elementary FMC/TFM, the only relations are the array
pitch, velocities, and, when the TFM process is not adaptive,
the relative geometry of the search unit with the part.
d Complex or high-performance TFM methods offer
greater flexibility to correct for the lack of knowledge of
the inspected part and its characteristics, enhance the resolution,
improve profiling of the indication, reduce material
structural noise, etc.
TFM is the result of the computation from data that was
acquired independently. It brings possibilities such as
using different processing, with the same FMC data, at
the same time or in post processing, using different algorithm
s. This may be advantageous for a particular examination
scenario.
F-460 CALIBRATION
F-462 GENERAL CALIBRATION REQUIREMENTS