© 2008 Karkia Industries All rights reserved
While the purpose of weld quality testing is to provide the information necessary to qualify a weld to a minimum standard, the goal must be to provide valuable timely information for the continuous improvement in welding performance, weld quality, and production rates; as well as minimize potential liabilities and risks associated with the construction process and post project operation.
Pipelines represent a tremendous investment by the owner companies an investment that includes considerable construction costs that today are proactively managed through the use of higher tensile materials, improved welding processes, and superior inspection technologies to extend asset life and reduce capital expenditures.
The increased application of fracture based weld acceptance standards enable making pipeline welds fit for purpose. This is a significant departure from earlier workmanship standards. Building to performance based standards requires a high degree of inspection expertise to apply in conjunction with a variety of worldwide standards.
This expertise, and track record for world-class service delivery resides within the Applus-RTD family of companies and its partner Karkia.
- Automated Ultrasonic Testing (AUT)
Qualifying welds by Automated Ultrasonic Testing (AUT) techniques represents a significant improvement in inspection efficiencies, critical anomaly detection, and flaw sizing performance from traditional inspection technologies.
Technology development as it applies to AUT was pioneered by RTD in the late 1960’s. The technology as we know today began in conjunction with the
PRCI and Nova Gas Transmission in the 1980’s. Since its inception RTD has been intimately involved in promoting and developing the technology and systems as they appear in today’s industry.
The RTD Rotoscan® AUT system is used
for weld inspection. It provides detailed
information on the position, size, and
orientation of defects.
Using either a conventional multiple
ultrasonic transducer, or phased array
set-up the system scans a weld in a
single pass. The operator is then able to
view the results in a graphical
TOFD is an advanced, full volume ultrasonic examination method that can
be used to inspect welds where a fully automated system may not be practical. The principal of TOFD is substantially different from conventional pulse echo techniques.
TOFD utilizes two angle compression
wave probes in a pitch-catch
arrangement. These are placed on each
side of the weld or inspection area. The
system measures the arrival times (time
of flight) of the various signals.
TOFD can determine the height,
location, and length of weld defects.
Inspection time is very quick; with
minimal setup time required and can be
manual, semi or fully automated
Exceptional inspection tool for unique
weld geometries such as flanges or
buckle arrestors. (more..)
The Phased Array concept concerns multi-element transducers. Each element of these transducers is connected to a different electronic channel, either directly or through multiplexers, according to electronic device performances.
Each element can be activated or not for each shot. The size and the location of the active aperture of a phased array transducer depends on the activated elements.
An electronic delay can be applied to each
electronic channel when emitting and receiving
the signal to/from the transducer elements.
The setup corresponding to all the delays of
a given shot is called Delay Law. Each delay
law defines a different acoustic beam with
particular direction, focusing distance and
lateral resolution. This technique requires
probes with very low acoustic and electric
cross coupling between the elements, so that
all the elements could be fired independently.
Phased Array techniques has a wide range of
application in maintenance and in service
Conventional versus Phased Array Rotoscan:
In conventional multi-probe Rotoscan® system:
- 16> transducers
- long calibration procedure
- calibration by hand
- bulky scanner frame
but in Phased Array Rotoscan® System:
- only two transducers
- short calibration process
- calibration with software
- compact scanner frame