Weld Integrity Mapping
Weld integrity mapping uses advanced ultrasonic techniques — phased array (PAUT) and time-of-flight diffraction (TOFD) — to build a positional picture of a weld rather than simply reporting whether an indication is present. Phased array steers the sound beam electronically through a range of angles, and TOFD measures the diffracted signals from the tips of a flaw, which allows a defect to be located and its through-wall height measured with good accuracy.
Why weld integrity mapping matters
Knowing that a weld contains a defect is less useful than knowing exactly where the defect is, how large it is, and whether it is growing. Accurate sizing lets an engineer apply fitness-for-service criteria — deciding whether a flaw is acceptable, monitorable, or must be repaired — instead of scrapping serviceable welds on a conservative call. Because the data is positional, a later inspection can be compared directly against the earlier one to establish whether a flaw has changed.
What it detects
Where it is applied
- ●Critical structural and pressure welds
- ●Fitness-for-service assessment
- ●Welds requiring accurate defect sizing rather than pass/fail
- ●Baseline surveys for later comparison
DELIVERED USING ULTRASONIC TESTING (UT)
Applicable Standards
SANS 3577-2, ISO 17640, ASME Section V
Professional Equipment
GE USM Go+ Flaw Detectors, Olympus EPOCH 650, Phased Array Systems
Common questions
How is this different from conventional ultrasonic testing?
Conventional UT uses a fixed beam angle and reports indications largely on amplitude. Phased array sweeps many angles electronically and produces an image of the weld cross-section, while TOFD measures flaw height directly. The result is accurate location and sizing rather than a pass or fail against a reference level.
Can it be used instead of radiography?
In many applications yes, and it has real advantages: no radiation, so no exclusion zone and no interruption to surrounding work, plus direct depth information radiography cannot give. Which method applies is governed by the client's specification and the code the weld is built to.
Does mapping let us track a defect over time?
Yes. Because results are recorded positionally rather than as a written note, a later inspection can be compared against the earlier record to determine whether an indication has changed, which is the basis for monitoring rather than immediately repairing.
Where we deliver it
MPIA Services is based in Durban (also known as eMkhomazi), KwaZulu-Natal, and carries out weld integrity mapping on site across all nine South African provinces. Mobile field units travel to the asset, so the work happens in place — on live rail corridors, in yards and depots, and at industrial sites — rather than requiring components to be sent away. See where we work.
Need weld integrity mapping?
Tell us the asset, the standard you need to satisfy and where the work is. We will come back with scope, timing and a quotation.
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