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Evaluation
of Ultrasonic Technology for Volumetric Weld Inspection of
Pipeline Girth Welds
| Category: |
Materials
|
| Project Number: |
PR-220-9437 |
| Catalog Number: |
L51776 |
| eBook Version Available:
|
Yes, L51776e
|
| Publication Date: |
December 01, 1997 |
| Author(s): |
Dijkstra, F.H.; Blinde,
M.R. |
| Research Agency: |
RTD Quality Services (Rontgen
Technische Dienst bv) |
| Pages: |
226 |
| Binding Type: |
GBC |
| Software Included: |
No |
| System Requirements: |
N/A |
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here to view Table of Contents
Abstract:
Need:
A system for mechanized ultrasonic inspection of girth welds
during pipeline construction, the RTD Rotoscan, has already
been available for twenty years. Its development started back
in 1977. First commercial use started around 1981. Today,
RTD Rotoscans are being used all over the world whereby, for
a number of pipeline projects, it replaces radiography as
a sole girth weld inspection technique. Although the early
version of the Rotoscan system, as already stated, was already
commercially in use and improvements were considered, it was
thought that a thorough and structured evaluation of the potentials
of mechanized UT systems for pipeline girth welds was highly
desirable. A major obstacle in the introduction of this kind
of systems was found to be the fact that in industry only
a limited generic insight was present on the performance of
mechanized UT systems in terms of Probability Of Detection
(POD) and sizing capabilities on one hand, and the likelihood
of ?false calls?, causing unnecessary and costly repairs on
the other hand. It had been experienced that, rather than
generic acceptance, potential customers therefore wish to
evaluate the system for their own specific applications and
on their own representative test welds for the purpose of
system qualification.
Benefit:
The work performed in this project can be regarded as a
continuation of an earlier PRCI project: "Evaluation
of Ultrasonic Inspection Techniques for the Root Region
of Girth Welds" (project PR-220-9123), which was completed
by the end of 1995. In that project, the performance of
modern systems for mechanized ultrasonic inspection of girth
welds in pipelines was evaluated with the emphasis on the
weld root, which can be considered historically as the most
difficult part of the weld when it comes to conventional
ultrasonic inspection. In the current project, this was
extended to the entire weld. Already in report PR-220-9123,
it was stated that a structured evaluation would also help
to arrive at a generic approval of mechanized UT systems
for use in pipeline industry, to reduce or replace job-specific
qualification tests. This point is still valid. The results
of the first project, and hopefully also of this one, will
be an important basis for international efforts currently
being undertaken to develop such approvals, as well as to
arrive at adapted acceptance criteria for weld defects.
The current project was, similarly to the previous one,
built around a number and a variety of representative test
welds, using different welding techniques. These were inspected
with Rotoscan, also using improvements (such as simultaneous
TOFD), partly initiated on the basis of the work done in
the previous project, and with radiography. They were then
destructively tested for correlation with the NDE results.
Result:
The results of this project confirm that mechanized ultrasonic
inspection can be considered as a mature alternative for
radiography. In terms of inspection quality, mechanized
ultrasonic inspection can even be superior over radiography,
if applied with optimum inspection parameters. Moreover,
ultrasonic methods can, contrary to radiography, be applied
with Engineering Critical Assessment (ECA) acceptance criteria.
Price: $995.00
L51776
is included in the Ultrasonic
Pipeline Reports Compendium
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