Choosing an instrument means choosing a measuring method. This section explains how ultrasonic testing works, what sets one mode apart from another and which standards govern the subject.
- ✓ The measuring modes explained one by one, with their use
- ✓ Flaw detection: A-Scan, B-Scan, reference curves
- ✓ Transducers, coupling and difficult materials
- ✓ The reference standards for measurement, welds, plants and qualifications
Ultrasonic non-destructive testing is based on a simple principle: an acoustic pulse is sent into the material, meets an interface and comes back. By measuring the time taken, and knowing the speed of propagation in the material, a distance is obtained. Both thickness measurement and the search for internal flaws derive from this idea.
Around that principle, different measuring modes have been developed, each created to solve a specific problem: ignoring a coating, measuring through a corroded surface, reading very thin thicknesses, evaluating the amplitude of an echo at different depths. Knowing them helps you choose the right instrument and, before that, understand when a reading is reliable.
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The second half of this section is devoted to standards. An ultrasonic inspection does not just produce a number: it produces a document that must stand up to scrutiny by a client, an inspection body or a test engineer. Standards define the method, the requirements of the instrument and the qualification of the person carrying out the test.
The technologies
| Area | What you will find |
|---|---|
| Ultrasonic thickness measurement | Pulse-Echo, Echo-Echo, ThruPaint, PECT, PETP, Coating Thickness, calibration |
| Flaw detection | A-Scan, B-Scan, DAC and DGS curves, TCG, angle probes |
| Ultrasonic bolt tension | Elongation measurement, temperature compensation, comparison with torque |
| Transducers and couplant | Dual and single element, delay line, high temperature, couplants |
| Materials and difficult cases | Cast irons, composites, corroded surfaces, high-temperature measurements |
| Measurement data management | Data logger, mapping grids, data download, reporting |
The standards
The standards concerning ultrasonic testing are spread over four distinct levels: the thickness measuring method, weld inspection, the integrity of plants in service and the qualification of the person carrying out the test. To these are added the standards on the tightening of bolted joints.
The following pages describe the purpose and scope of each standard and indicate where Dakota NDT instruments stand in relation to it. The declarations of conformity of the individual models are given in the respective product pages.
| Area | Standards covered |
|---|---|
| Standards for thickness measurement | EN 14127, ASTM E797, EN 15317, ISO 16809 |
| Standards for weld inspection | AWS D1.1, EN ISO 17640, EN 12668-1, ASME Section V |
| Plant standards and asset integrity | API 570, API 653, API 510, PED Directive |
| Standards for bolted joint tightening | ASME PCC-1, EN 1090 |
| Qualification of personnel and equipment | EN ISO 9712, EN 4179 and NADCAP, NIST traceability, ISO 9001 |
Frequently asked questions
Thickness measurement looks for the back-wall echo to determine how much material there is between the probe and the opposite surface. Flaw detection instead looks for the echoes returning from internal discontinuities, and evaluates their amplitude and position.
Because each solves a specific problem: ignoring a coating, working on corroded surfaces, reading very thin thicknesses or measuring the metal and the protective layer separately. The choice depends on the part, not on the operator’s preferences.
On the page of each model, which lists the standards declared by the manufacturer, and in the technical documentation attached to that page.
For advice on choosing the method or instrument suited to your case, write to us from the Contact page.
Further information and contacts
Systems division and sensor integration partner : www.roder.it
More information about RODER SRL : about us
Contact for general information : info@roder.it
Contact for information about these products : info@roder.it
The information contained on this web page is provided for information purposes only. Although it has been compiled with the utmost care, it does not constitute a contractual offer or a binding commitment to supply. It may contain transcription, translation or typographical errors. For precise and up-to-date information, please contact our company directly.
Some images on this website have been intentionally generated using Artificial Intelligence (AI). This is because, for many applications and projects, it is not possible to disclose photographs of the installation or of the actual system due to confidentiality agreements, confidentiality clauses and non-disclosure agreements (NDAs).