Spelling suggestions: "subject:"phased array ultrasonic ingesting"" "subject:"phased array ultrasonic andtesting""
1 |
Inspection of Steel Bridge Welds Using Phased Array Ultrasonic TestingCurtis J. Schroeder (5930243) 03 January 2019 (has links)
<p>The objective of this research is to develop
recommendations on calibration standards, scanning procedures, and acceptance
criteria for phased array ultrasonic testing (PAUT) of complete joint
penetration butt welds within the AWS D1.5 Bridge Welding Code. These recommendations include the development
of a rational acceptance criteria which is based in engineering analysis and
fracture mechanics. It is expected that
the updated scanning procedures and acceptance criteria will result in improved
reliability for bridges and improved consistency in bridge fabrication quality.</p><p><br></p>
<p> </p>
<p>While PAUT was included in the 2015 edition of AWS
D1.5 in Annex K, the acceptance criteria for this procedure was developed as an
adaptation of an existing conventional ultrasonic testing (UT) acceptance
criteria in AWS D1.1. Therefore, the
acceptance criteria in AWS D1.5:2015 is a workmanship-based criteria and is not
based on engineering analysis of the criticality of weld flaws. The scanning procedures and application of
PAUT inspections of bridge welds according to this procedure differ greatly
from the scanning procedures outlined in AWS D1.5 for conventional UT
inspections. Previous research has shown
that differences in flaw rejection are possible for PAUT and conventional UT
ultrasonic methods under the AWS D1.5:2015 approach.</p><p><br></p>
<p> </p>
<p>In order to develop recommendations for improved
calibration standards, scanning procedures, and acceptance criteria for PAUT
within AWS D1.5, this research project utilized both analytical techniques and
experimental testing. This research
project included determination of target critical flaw sizes for routine detection
and rejection through fitness-for-service evaluations. This was followed by a round robin ultrasonic
testing program in order to collect data on the variability of inspection
results of eleven weld samples with nineteen weld flaws using different
ultrasonic inspection techniques. Next,
calibration requirements were developed to account for differences in
ultrasonic attenuation and shear wave velocity between calibration blocks and
test objects. Development of these
requirements included experimental testing of base metals and weld metals,
along with simulations of ultrasonic inspection using commercial software. Finally, minimum requirements for weld
scanning procedures, reference standard reflectors, and corresponding amplitude
limits for detection and rejection of target critical weld flaws were developed
using ultrasonic inspection simulations and verified through experimental
testing of weld samples with known weld flaws.</p>
|
2 |
Phased Array Ultrasonic Testing of Austenitic Stainless Steel Welds of the 11 T HL-LHC Dipole MagnetsLorentzon, Marcus January 2018 (has links)
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.
|
Page generated in 0.0917 seconds