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.