advances in phased array weld inspection scan plan designs
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Advances in Phased Array Weld Inspection Scan Plan Designs
Compound S-Scan for Improved Weld Flaw Detection and Sizing
Chris Magruder
October 26, 2016
2016 ASNT Annual Conference Long Beach, CA
Advances in Phased Array Scan Plan Designs — Presentation Overview • ASME phased array scan plan design definitions. • Compound S-scan setup and configuration. • Compound S-scan beam resolution. • ASME compliance and essential variables. • Compound S-scan calibration and configuration. • Compound S-scan vs S-scan coverage comparison. • Compound S-scan API 650 9%Ni cryogenic data example. • Compound S-scan ASME B31.3 carbon steel weld data example.
• E-scan: A single focal law multiplexed across a group of elements for a
constant angle beam stepped along the probe length. • S-scan: Set of focal laws that provides a fan-like series of beams through a
defined range of angles using the same elements. • Compound S-scan: Set of focal laws using a fan-like series of beam
movements through a defined range of angles and elements. The compound S-scan combines the E-scan and S-scan in a single acquisition group.
Advances in PA Scan Plan Designs — ASME V Art 1 121.2 UT Definitions
Compound S-scan Azimuthal S-scan Linear E-scan
• Select probe frequency and aperture. • The aperture is limited by the pulser configuration and element pitch. A simple
rule of thumb is to reproduce the size of the equivalent UT probe. • Position the probe as close to the weld as possible with respect to the first and
last A-scan position\angle that is needed for full volumetric coverage. • Near-side wall fusion is best detected as close to perpendicular as possible.
72 degrees
Advances in PA Scan Plan Designs — Compound S-Scan Setup
• The beam resolution will determine the number of A-scans in the compound
S-scan. • This parameter significantly affects flaw resolution, file size, and scanner speed.
72 degrees
Advances in PA Scan Plan Designs — Beam Resolution
• In the example below, all compound S-scans use the same beam aperture and
the same first and last A-scan angle and beam exit position in the wedge. • They only differ in beam resolution, which greatly affects acoustic results. • In addition to the S-scan beam resolution, results are also affected by the
proximity of the probe to the weld (beam spread) and probe frequency.
Advances in PA Scan Plan Designs — Beam Resolution cont.
• The beam resolution will determine the # of A-scans in the compound S-scan and
the beam-to-beam distance on the weld bevel that affects flaw height sizing. • Flaw resolution on the weld bevel is a function of many factors, including the
sound path distance from the probe to the weld, probe frequency, aperture, focus, and beam orientation.
Advances in PA Scan Plan Designs — Beam Resolution cont.
• The compound S-scan scan plan is defined for the PA calculator or work
procedure by populating the parameters of both the linear E-scan and S-scan in ASME V Art 4 Appendix V Table V-421.
72 degrees 40-72
.5 deg
32 (1-29)
1-29
55 shear
32mm
40mm half path
PWZ1 5L60
1mm \ .9mm \ 60 \ .1mm
40-72
1
Advances in PA Scan Plan Designs — ASME Compliance
60 \ 10 \ .1
• The compound S-scan is compatible with traditional phased array sensitivity and time-of-flight (TOF) calibrations.
• With regard to UT settings, gate position, C-scan configuration, and other functions, the compound S-scan does not require any special accommodation and is compatible with normal work procedure.
Advances in PA Scan Plan Designs — Calibration and Work Procedure
• Although a two group S-scan strategy from the front and back of the probe is possible with any 32 or 64 element probe, use of a single compound S-scan results in less setup and calibration time, more inspection coverage, and faster analysis.
2X 40–72 at 1 degree compound S-scan 4X 40–72 at 1 degree standard S-scan
Advances in PA Scan Plan Designs — Compound S-scan vs S-scan
• Below is a comparison of a standard and compound S-scan with the same aperture and focus inspecting a 12.7 mm V weld.
• Detection, sizing, and characterization are similar in this thickness, but the compound S-scan index position is 8 mm closer to the weld and more easily adapted to a range of bevel thicknesses using the same setup and calibration.
Advances in PA Scan Plan Designs — Compound S-Scan vs S-Scan
• The data sample below is two-sided coverage of a 12 mm V weld. • 5L32 0.6 mm pitch probe. • No significant loss in flaw characterization and sizing as is typical in a single
angle linear scan, also called an E-scan.
Advances in PA Scan Plan Designs — Data Example
• Ability to use one setup configuration for a range of bevel thicknesses. • Thin section data sample. • 4L32 1 mm pitch probe.
Advances in PA Scan Plan Designs — Data Sample 9% Ni LNG Shell
20 mm 15 mm 10 mm
• Ability to use one setup configuration for a range of thicknesses. • Thick section data sample.
Advances in PA Scan Plan Designs — Data Sample 9% Ni LNG Shell
25 mm 35 mm
• 25 mm double V weld bevel coverage comparison of compound and standard S-scans with a 1 mm pitch, 60 element probe.
Compound S-scan Standard S-scan 2X Standard S-scan
Advances in PA Scan Plan Designs — Data Sample ASME B31.3
• Flaw detection, sizing, and characterization meet and exceed the needs of ASME B31.3, I, V, VIII, and similar referencing codes.
31 mm V weld bevel coverage using a 32 mm aperture compound S-scan.
Advances in PA Scan Plan Designs — Data Sample ASME B31.3 cont.
• Full volumetric coverage, including the heat affected zone (HAZ), on a 1.219 in. bevel is achieved in a single group line scan with the probe adjacent to the weld toe.
31 mm V weld bevel coverage using a 32 mm aperture compound S-scan.
Advances in PA Scan Plan Designs — Data Sample ASME B31.3 cont.
• Fewer files, faster setup and calibration, fewer acquisitions, and less time analyzing is made possible through the use of a compound S-scan.
31 mm V weld bevel coverage using a 32 mm aperture compound S-scan.
Advances in PA Scan Plan Designs — Data Sample ASME B31.3 cont.
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