D-Scan
A D-scan is an end-view ultrasonic display showing depth versus probe index axis (the secondary scan direction), used in encoded raster scanning to visualize defect distribution across the weld width.
Definition
The D-scan is the depth-versus-index view in a raster ultrasonic scan, complementary to the B-scan (depth versus scan axis) and C-scan (plan view). Together, B/C/D scans give the operator three orthogonal projections of the data volume.
What it represents
An ultrasonic presentation showing a top-view slice at a selected depth — with B- and C-scans it completes the set of orthogonal views reconstructable from encoded scanning data.
How it is derived
In phased array and TOFD work the D-scan (end view along the weld axis in most software conventions — vendors disagree on naming) lets an analyst walk through a weld volume slice by slice, separating a continuous planar flaw from a chain of discrete ones — a distinction that changes the acceptance verdict.
Where it is defined
Encoded-data presentations underpin ASME Section V Article 4 mandatory appendices for PAUT recording.
How it is misread
Vendor naming: one platform's D-scan is another's side or end view. State the viewing plane in the report rather than trusting the label — analysts reviewing on different software have mis-read geometry from exactly this.
Where D-Scan fits in an inspection programme
A term is only useful when it connects to a decision. D-Scan appears in written procedures, in technique sheets, and in the records an owner or accreditation body reviews afterwards — which means the way it is defined in your documentation has to match the way it is applied on site. Where the two drift apart, audits find it. Atlantis writes and reviews procedures against the governing codes, trains inspection personnel to apply them, and builds the record-keeping that makes the evidence retrievable years later. Procedure development and code consulting · NDT training and certification · Ask us about your programme.
Related terms
- B-Scan — A B-scan is a cross-sectional ultrasonic display showing depth (vertical) versus probe position along the scan axis (horizontal), with signal amplitude encoded as brightness or color, used for thickness profiling and corrosion mapping.
- C-Scan — A C-scan is a plan-view ultrasonic display showing peak signal amplitude (color-coded) at every (X, Y) probe position across the inspected surface, producing a top-down map of internal flaws or wall loss.
- Ultrasonic Testing (UT) — Ultrasonic Testing (UT) is an NDT method that uses high-frequency sound waves (typically 0.5–25 MHz) to detect internal flaws and measure thickness in metals, plastics, and composites by analyzing reflected echoes from a transducer.
More data terms
A-Scan · S-Scan · L-Scan · Distance-Amplitude Correction · Distance-Gain-Size · Time-Corrected Gain · Gating · Decibel · Indication · False Indication
Where this comes up in practice
Terms like this one appear in three places that matter commercially: the written practice that governs how your personnel are qualified, the procedures and technique sheets that define how an examination is actually performed, and the evidence an auditor or client asks for when they want to know why an inspection was accepted. Getting the terminology right is the easy part; being able to produce the qualification record, the calibration traceability and the procedure revision that applied on the day of the inspection is the part that decides audits.
Atlantis NDT provides NDT training and certification against ASNT SNT-TC-1A and ISO 9712, ASNT Level III consulting for written practices and procedure approval, inspection management software that holds qualification, calibration and procedure-revision evidence in recoverable form, and an asset integrity platform that binds inspection results to the asset they describe. Browse the full NDT glossary or ask a Level III directly.