Capitol Ultrasonics is capable of employing different
techniques for complete automated ultrasonic inspections. The different technologies include Corrosion
Mapping (CM), Hydrogen Induced Cracking (HIC), Phased Array (PAUT),
Time-of-Flight-Diffraction (TOFD) and Electric Magnetic Acoustic Transducer
The benefits of AUT
- Ultrasonic data recorded for permanent records
- Accurate results and repeatable inspections
- Reduces cost by minimizing vessel entries and
- Large areas scanned in quick time
- Inspection performed while equipment is in
serviceInformation used for remaining life programs
Capitol Ultrasonics has the option of three different types
of automated systems to use to provide complete automated inspection
capabilities. We have a scanner with a
C-Scan arm that can crawl up tanks and cross welds which would save cost on
having scaffolds built. We have two
channel systems to use for pipeline and quick inspection jobs, we also have
eight channel systems for jobs consisting of multiple transducers (combining
wave modes) or for jobs consisting of acquiring data for very large inspection
Corrosion Mapping is used for detection of corrosion/erosion on piping
systems, vessels, tanks and drums, etc.
Corrosion Mapping (CM) utilizes a color code system (C-Scan) for the
thickness range for detection of thin areas on base materials. CM is collected in C-Scan, B-Scan and A-Scan
displays with an AUT system with consist of computer, UT boards, motor control
and automated scanner to map out and record the size and shape of corrosion and
Hydrogen Induced Cracking (HIC)
Ultrasonics AUT HIC System uses a longitudinal wave for detection of the
component’s thickness and potential hydrogen induced blistering or laminar type
indications. Two transverse waves are
used for detection of ID connected cracks of cracks that may propagate from
blisters. Both wave modes are in a
single case transducer. With the
computer software a volumetric projection can be made to merge the longitudinal
and the transverse wave data simultaneously, which would allow on a B-Scan the
longitudinal reflectors from the blisters and the indirect and direct
transverse reflectors from cracking to be color coded.
Induced Cracking Examination (HIC), hydrogen damage takes place at two
temperature regions, at high temperatures, the elevated solubility of hydrogen
allows hydrogen to diffuse into the metal and temperatures at ambient and
slightly above hydrogen can diffuse assisted by a concentration gradient. High concentration of hydrogen can cause
blisters, once the ductility of the metal has reduces to a significant amount,
the metal will actually crack, cracks can occur from the blisters to the inside
diameter, or from blister to blister.
Phased Array Ultrasonic Testing (PAUT)
Capitol Ultrasonics uses a Olympus Mx2 unit with (4)
different types of scanners to encode Phased Array Data, the pipe ranges start
at 2 inch, large scans can be done on tanks also. Phased Array encoded scans are often used as
an alternative to Radiography, phased array produces reliable images with
multiple presentations simultaneously, which increases inspection speed. Phased Array can be used for corrosion
mapping, flaw detection and with multiple angles from a single probe greatly
increases the probability of detection of anomalies.
Array uses beam steering, commonly referred to sectorial scan, can be used for
mapping components at appropriate angles, electronic focus permits optimizing
the beam shape and size at the expected defect location which improves
detection ability. All encoded data is on a storage card which can be down
loaded on a thumb drive for our clients when requested.
Capitol Ultrasonics LLC can use TOFD along with Phased Array
with an Olympus MX2 Unit for automated inspection of welds for flaw
characterization and accurate height sizing.
TOFD offers great accuracy for measuring critical through-wall size of
crack flaws. TOFD uses a pitch and catch
mode to receive two wave modes, one travel along the surface (Lateral Wave) and
the other that reflects off the far wall (back wall reflection). The TOFD data is displayed in a grayscale
TOFD the accuracy of better than ± .039” can be obtained in a wide range of
material thickness for monitoring and sizing wall height in service
discontinuities. When a crack and/or
discontinuity is present, there is a diffraction of ultrasonic sound wave from
the top and bottom tips of the crack.
Using the measured time of flight of the pulse, the depth of the crack
tips can be calculated.
Electro Magnetic Acoustic Transducer (EMAT)
Ultrasonics uses EMATs for straight beam inspection, surface wave, and
medium-range UT. EMAT can be used on
ferromagnetic and non-ferromagnetic materials.
EMAT does not use complaint so it permits inspection of very cold and
High temperature EMAT thickness reading are
very fast, efficient and accurate at temperature ranges up to 1200°F. EMAT surface wave (Rayleigh waves) are useful
because they very sensitive to surface defects and they follow the surface
around curves. Surface waves can be used
to inspect areas that other waves might have difficulty reaching.
Medium-Range UT is designed for inspection of
pipe, using a circumferential scan to provide a full volumetric inspection of
the pipe (example: under supports).
Axial scan permits inspection of supports and soil interfaces. Medium –Range UT uses lamb waves which travel
throughout the material with both vertical and forward motion in an elliptical