The document outlines key considerations for phased array scan planning in weld inspections, emphasizing the importance of a documented inspection strategy to ensure consistency and repeatability. It discusses variables such as probe selection, focal law configuration, and scanning methodologies, detailing the essential steps for effective coverage of weld joints. Additionally, it examines the complexities and variability inherent in phased array inspections, encouraging meticulous planning to optimize detection of potential flaws.

1. Phased Array Scan Planning
Considerations for Weld Inspection
University of Ultrasonics
Olympus Scientific Solutions Americas Webinar
February 4th, 2014

2. • Scan Planning Introduction
• Basic Scan Plan Requirements
• Basic Methodology
• Hands-on Demonstration
Short Course Outline

3. Scan Plan History
• Scan planning is deeply rooted in day-to-day conventional
UT routines:
– Evaluating Transducer Characteristics
– Determining proper “pullback”/skip distance for Angle Beam
– Beam overlap for C-Scan coverage
– Focal Spot Size Calculations

4. Scan Plans???
• Before ANY Phased Array Inspection is
performed a SCAN PLAN should be in place.
– Scan Plans – A documented inspection strategy (plan
of attack) to provide repeatability for inspections.
These will aide in evaluating the material and provide
insight to individuals reviewing data.

5. Scan Plan Importance
• Variability of Phased Array inspections can create issues in
consistency, repeatability, and personnel training
• The above scan plan includes several scan plan variables, can you find
them???

6. Phased Array Variability
• Sectorial Scanning
• E-Scanning
• Encoded vs. Manual
• Aperture Determination
• Multi-Channel/Grouping
• Focusing effects
• Transducer Selection
– Frequency & Beam
Spread Considerations
• Angle Selection

7. Scan Planning
Code Perspective

8. Scan Plan Variables
• Phased Array Scan plans should
provide at minimum:
– Part Details (Weld Design,
Curvatures, Connections)
– Probe and Wedge to be Used
– Focal Law Configuration to be
Used (Including initial instrument
settings)
– Index Offset Info
– Number of Scans
– Direction of Scans

9. ASME Example Requirements
• Section V
Article 4
• Requirements
of Scan
Planning in
Appendix V

10. AWS Example Requirements
 D1.1
 Info Related to
Scan Planning
under Part G
 Testing
Procedure under
Annex S

11. API Example Requirements
 1104
 Info Related to
Scan Planning
 Procedure
specific
 Specialized
Calibration
Requirements

12. Phased Array
Scan Plan Equipment

13. • Forming a scan plan involves 3 essential variables:
– Part Configuration
– Probe & Wedge Selection
– Focal Law Selection
• Information may be hand-drawn or plotted via software
Scan Plan Essentials

14. • Pros:
– Accounts for errors in Equipment
– Plots actual beam index point
– Focal Law adjustments visualized
• Cons:
– Time Consuming
– Visual Measurements
– Requires Equipment
– Actual Inspection piece may vary
Hand-Drawn

15. • Pros:
– Fast and efficient
– Easier Part Drawing/Dimensioning
– Traceable & Transferable
– Flexibility on Custom Parts
• Cons:
– Equipment Variations
– Part Variations
– Estimation of Focal Laws
– Manual Prove up required
Software

16. • Choosing the proper equipment is as much scan
planning as choosing the proper angles or focal laws.
• Transducers should be proper for material properties
• Wedges should allow for good contact and transmission
• Instruments should be capable of handling both
Equipment Selection

17. • Differences in array patterns will provide unique beam
characteristics
• 4 Primary Variables:
– Element Qty. - A
– Element Size - E
– Pitch - P
– Elevation - H
Element Configuration
p g
e
H
A

18. • Focusing in Phased Array is
dependent upon the Aperture used
and Pitch of those elements
• Larger Pitch Transducers and Higher
Aperture sizes will provide better
focusing
• Sometime necessary when Height
Sizing is important
“VPA” Considerations - Focusing
16 element
aperture
32 element
aperture

19. • Steering in Phased Array is
dependent upon the amount of
beam spread from individual
elements
• Over steering a transducer can
lead to grating lobes, resolution
losses, and increased errors in
refracted angle
• Smaller Element Sizes and
Reduced Pitches aid in steering
“VPA” Considerations - Steering

20. • Caution should be taken in using Phased Array in Axial
or Long Seam weld inspections
• Smaller equipment is easier to use as the compensation
through focal laws may not be necessary
• Larger wedges create non-linear focal law calculations
that sometimes require the addition of special software
Curvature Considerations

21. Phased Array
Scan Plan Creation

22. • From the perspective of the technician, a scan plan
provides instruction for probe placement and focal law
creation
• With no direct code instruction and high variance on
Phased Array use, this leaves more room for
interpretation and how to provide these instructions
• 2 Extremes of Scan Plan Creation
– Minimalistic
– Flood Method
Scan Plan Thoughts

23. • From a Code standpoint, coverage is the only requirement and the
minimalist approach fulfills only that basic necessity
• Pros: High-Speed, minimal setup time, ease of analysis
• Cons: May require manual follow up, risk of undercalling, difficulties in flaw characterization
Minimalist Scan Plans

24. • From a Detection standpoint, flaw orientation is always
variable and is best detected by multiple beam positions
• Pros: High Resolution, Increased Probability of detection, Improved Sizing
• Cons: Slow Scan speeds, Longer Analysis/Setup times
Flood Scan Plans

25. • First need a plan of attack….
– How am I to approach the inspection? (Single side
access…duel side access..etc.)
– What types of flaw mechanisms are potentially present?
– What incident angles will best reveal the potential flaw
mechanisms?
– FLAWS ARE ANGULAR DEPENDANT
• Most codes simply state full volumetric coverage including the
Heat Affected Zone is required….. This is too vague.
• Breaking that required coverage into specific areas and
specific angles will provide consistency and reliability.
Scan Plan Focal Law Methodology

26. • More than just coverage!!!!
• Must interrogate specific parts of the joint with specific angles
which will provide optimum responses to suspected flaw
mechanisms.
• General coverage principles for Weld Inspection
– Root Coverage
– Fusion Zone Coverage
– Heat affected zone coverage
– Volumetric
• This does NOT indicate that 4 scans on each side must be
configured.…The number of scans is determined by your
proof of coverage.
Scan Plan Methodology Welds

27. • 1. Weld Root Interrogation – First objective is to index close
to the weld toe with the intent of weld root interrogation
– Primary Flaw Types: Lack of penetration, Root or ID Cracks,
Centerline Cracking in Double Vee Weld
– This is the most critical part of a weld joint and the first objective
to cover in scan planning.
– First have to consider the joint type and the potential flaws.
– This also assures maximum 1st leg inspection coverage.
Scan Plan Methodology continued

28. • 2. Fusion Zone Coverage – second objective is to ensure the
fusion zone is covered WITH SPECIFIC ANGLES.
• Primary Flaw Types: Lack of side wall fusion, Sidewall Cracking
• With conventional ultrasonics, the optimum bevel incident angle (BIA) is
considered between 5 and 7 degrees of normal incidence with some
dependency on the frequency of the sound wave.
• Studies have found that with Phased Array, the optimum BIA with
• Sectorial Scans = +/-10 degrees of normal incidence
• E-Scans = +/-5 degrees of normal incidence.
Scan Plan Methodology continued

29. • Example:
– With a 30 degree bevel – perfect bevel incidence would result
from a 60 degree refracted shear wave.
– Fusion Zone to be covered with refracted waves between 50
and 70 degrees (+/- 10 of 60 degrees.)
50
70
Scan Plan Methodology continued

30. • 3. Heat Affected Zone (HAZ) Coverage – The total code specified
area of interest must be covered. ASME specifies the weld zone
plus 1” or “t” whichever is less for materials less than 3” thick.
– Primary Flaw Types: CRACKING
– Studies have identified that optimum responses from a notch corner
result from shear waves between approximately 35 and 58 degrees.
– Plan for these angles to interrogate the HAZ zone.
– Occasionally, HAZ coverage may be specified as being achieved on the
probe side for a given index position.
Scan Plan Methodology continued

31. • 4. Volumetric Coverage – If the previous three steps
are complete, this will be sufficiently covered without
addition considerations.
– This is for slag and porosity detection which are typically omni-
directional type reflectors (similar to a Side-drilled hole, omni-
directional reflectors tend to reflect sound regardless of the angle
of attack).
Scan Plan Methodology continued

32. Thank You!
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