UT Ultrasonic

Ultrasonic testing evaluates the reflection of a high-frequency sound wave sent into the material from discontinuities and from the back wall. It is a volumetric method: it detects flaws beneath the surface and measures their depth.

The aim is to find and locate volumetric flaws such as internal cracks, lack of penetration, slag and lamination. It is also the most common method for measuring wall thickness thinned by corrosion.

• Weld seams (butt and fillet welds)
• Wall-thickness measurement of pressure vessels and pipes
• Lamination in forged and rolled products
• Internal discontinuities in cast parts
• Storage tank shell plates

NDT has no interval of its own; how often it is applied follows the inspection programme it serves. In manufacturing the governing factor is the coverage required by the product standard and the specification (e.g. a given percentage of welds); in operation it is the asset integrity or risk-based inspection programme.

• Internal cracks and fatigue cracks
• Lack of penetration and lack of fusion
• Slag inclusion and porosity
• Lamination and layering
• Wall thickness and thinning caused by corrosion
• Depth, location and size of the discontinuity

• ISO/IEC 17020
• EN ISO 17640
• ISO 16810
• ISO 16811
• EN ISO 11666
• ISO 16809
• ISO 9712

• Ultrasonic flaw detector (A-scan)
• Normal-beam and angle-beam probes
• Reference calibration blocks (V1, V2, etc.)
• Couplant (contact medium)
• Thickness-gauge probe and instrument
• Surface preparation equipment

1. 1Selection of Method and TechniqueThe type and location of the discontinuity sought and the material properties are assessed to select a suitable method and technique; a written procedure is prepared.
2. 2Verification of Personnel and EquipmentThe level and industrial-sector qualification of the operator under EN ISO 9712 and the calibration records of the equipment are checked.
3. 3Surface PreparationThe inspection surface is prepared as the method requires; coating, rust and contamination directly affect the sensitivity of the method.
4. 4Calibration and Sensitivity VerificationA reference block or control specimen is used to demonstrate that the system can detect the discontinuity sought.
5. 5Performing the InspectionScanning is carried out according to the procedure; indications are recorded and located.
6. 6AssessmentIndications are evaluated against the applicable acceptance standard to determine whether they are defects; they are sized.
7. 7ReportingMethod, technique, equipment, calibration, findings and acceptance criteria are reported together.

Indications are assessed by echo height and length relative to a reference reflector; the acceptance criterion is determined according to a standard such as EN ISO 11666 and the applied quality level. In thickness measurement, the result is compared with the design minimum thickness.

• The inspection body and the personnel's EN ISO 9712 level and sector
• Method and technique applied and the written procedure number
• Part and weld examined, with a location sketch
• Equipment, consumables and calibration records
• Surface condition and inspection conditions
• Indications recorded, with their location and size
• Acceptance standard applied and the result of the evaluation
• Accept / reject decision

Non-destructive testing is carried out as an accredited inspection activity under ISO/IEC 17020. The second decisive factor in NDT is personnel qualification: the operator must be certified under EN ISO 9712 for the method, level and industrial sector concerned. An examination performed with a method outside the scope of that certificate is not valid. EUROLAB holds internationally recognised accreditation under ISO/IEC 17020, granted by accreditation bodies that are signatories to the ILAC mutual recognition arrangement.

• VT Visual
• PT Penetrant
• MT Magnetic Particle
• RT Radiographic
• ET Eddy Current
• PAUT
• TOFD
• Leak Testing