Phased Array Ultrasonic Testing of Austenitic Stainless Steel Welds of the 11 T HL-LHC Dipole

108 Pages·2017·11.94 MB·English

Linköping University | Department of Physics, Chemistry and Biology
Master’s thesis, 30 hp | Educational Program: Physics, Chemistry and Biology
Spring term 2018 | LITH-IFM-A-EX—18/3565—SE

Phased Array Ultrasonic Testing of
Austenitic Stainless Steel Welds of
the 11 T HL-LHC Dipole Magnets

Marcus Lorentzon

Examiner, Ferenc Tasnadi
Supervisor, Ching-Lien Hsiao and Christian Scheuerlein

Master’s Thesis
LiTH-IFM-A-EX-18/3565-SE
Phased Array Ultrasonic Testing of Austenitic Stainless
Steel Welds of the 11 T HL-LHC Dipole Magnets
Marcus Lorentzon
June 2018
Supervisor: Christian Scheuerlein
CERN, TE-MSC
European Organization for Nuclear Research (CERN)
TE Department - Magnets, Superconductors and Cryostats (MSC)
CH-1211 Geneva 23, Switzerland
Supervisor: Ching-Lien Hsiao
Linko¨ping University, IFM
Examiner: Ferenc Tasnadi
Linko¨ping University, IFM
Department of Physics, Chemistry and Biology
Link¨opings universitet, SE-581 83 Link¨oping, Sweden

Datum
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2018-06-11
Department of Physics, Chemistry and Biology

Linköping University

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Svenska/Swedish Licentiatavhandling ISRN: LITH-IFM-A-EX--18/3565--SE
Engelska/English Examensarbete
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Titel
Title

Phased Array Ultrasonic Testing of Austenitic Stainless Steel Welds of the 11 T HL-LHC Dipole Magnets

Författare
Author

Marcus Lorentzon

Sammanfattning
Abstract
A routine non-destructive test method based on Phased Array Ultrasonic Testing (PAUT) has been developed and
applied for the inspection of the first 11 T dipole prototype magnet half shell welds, and the test results are compared
with the radiography and visual inspection results of the same welds.
A manual scanner and alignment system have been developed and built to facilitate the inspection of the 5.5 m long
welds, and to assure reproducibility of the PAUT results.
Through the comparison of distance readings and signal amplitude for different focus lengths, a focal law with focus at
25 mm sound path has been selected for the routine inspection of the 15 mm thick austenitic stainless steel 11 T dipole
welds. The defocusing properties (beam spread) due to the cylindrical geometry of the half shells and the sound path
distance to the area of interest were taken into account.
Dedicated sensitivity calibration weld samples with artificial defects (side-drilled-holes) have been designed and
produced from 11 T dipole prototype austenitic stainless steel half shell welds. These provide representative
calibration for the strongly attenuating and scattering austenitic stainless steel weld material.
One scan with two phased array probes aligned parallel to the weld in 2 mm distance from the weld cap edge, and one
scan with the probes aligned parallel to the weld in 12 mm distance from the weld cap edge are sufficient to show if
the inspected welds fulfil the requirements of weld quality level B according to ISO 5817.
The standard test duration for the two scans of the two 5.5 m long horizontal welds of the 11 T dipole magnets is about
one day, provided that no defects are found that need to be characterized in more detail.

Nyckelord
Keyword

Phased Array Ultrasonic Testing (PAUT), non-destructive testing, austenitic stainless steel welds, CERN, HL-LHC,
11 T Dipole

ABSTRACT
Aroutinenon-destructivetestmethodbasedonPhasedArrayUltrasonicTesting(PAUT)hasbeen
developed and applied for the inspection of the first 11 T dipole prototype magnet half shell welds,
and the test results are compared with the radiography and visual inspection results of the same
welds.
A manual scanner and alignment system have been developed and built to facilitate the inspec-
tion of the 5.5 m long welds, and to assure reproducibility of the PAUT results.
Through the comparison of distance readings and signal amplitude for different focus lengths,
a focal law with focus at 25 mm sound path has been selected for the routine inspection of the 15
mm thick austenitic stainless steel 11 T dipole welds. The defocusing properties (beam spread) due
to the cylindrical geometry of the half shells and the sound path distance to the area of interest
were taken into account.
Dedicated sensitivity calibration weld samples with artificial defects (side-drilled-holes) have
been designed and produced from 11 T dipole prototype austenitic stainless steel half shell welds.
Theseproviderepresentativecalibrationforthestronglyattenuatingandscatteringausteniticstain-
less steel weld material.
One scan with two phased array probes aligned parallel to the weld in 2 mm distance from the
weld cap edge, and one scan with the probes aligned parallel to the weld in 12 mm distance from
theweldcapedgearesufficienttoshowiftheinspectedweldsfulfiltherequirementsofweldquality
level B according to ISO 5817.
The standard test duration for the two scans of the two 5.5 m long horizontal welds of the 11 T
dipole magnets is about one day, provided that no defects are found that need to be characterized
in more detail.
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ACKNOWLEDGEMENTS
I would like to express my deepest gratitude to all my colleagues at the European Organization for
Nuclear Research (CERN), who supported and encouraged me throughout this project and made
my stay in Switzerland a true pleasure. A special thanks to my supervisor Christian Scheuerlein
for giving me this very interesting thesis project and providing invaluable advice and support in a
wide range of problems. A big thanks to Gonzalo Arnau Izquierdo for sharing his deep knowledge
in ultrasonic testing.
I want to thank my examiner Ferenc Tasnadi and my supervisor Ching-Lien Hsiao at Link¨oping
University (LIU) for their help and their will to be part of this thesis.
Finally I want to thank my family and friends for always believing in me.
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