Overview
ISO 19675:2017 specifies requirements for a steel calibration block used to set up and verify ultrasonic test equipment for phased array ultrasonic testing (PAUT). The standard defines the block’s material, heat treatment, dimensions, surface finish, reference marks, and required ultrasonic checks (including velocity and attenuation tests). Its purpose is to ensure consistent, traceable calibration for non-destructive testing (NDT) using phased array techniques.
Key technical topics and requirements
- Material: Steel grade S355J0 (or equivalent) in accordance with EN 10025-2.
- Manufacture & heat treatment:
- Raw block rough-machined to 320 × 120 × 30 mm.
- Heat treatment: austenitizing at 920 °C for 30 min, quench in water, temper at 650 °C for 3 h, then cool in still air.
- Pre-machined size recommendation: 305 × 101 × 26.5 mm.
- Surface finish:
- After pre-machining: roughness ≤ 1.6 μm Ra.
- Final machining: roughness ≤ 0.8 μm Ra.
- Ultrasonic checks:
- Block must be free from internal discontinuities (straight‑beam longitudinal probe ≥ 10 MHz, 10–15 mm transducer).
- Attenuation: qualitative check - typically at least four back‑wall echoes above 25% FSH with recommended probe.
- Velocity measurements for longitudinal and transverse waves per Annex A (V = 2d/t); measurements taken in three perpendicular directions and at specified positions (temperature 17–23 °C).
- Transverse-wave checks require polarization measurements (fast and slow shear velocities).
- Dimensions & tolerances: Detailed in the standard (reflector positions, hole tolerances, overall size ±0.1 mm).
- Reference marks & marking: Permanent engraving (etching or laser preferred); block marked with a reference to the ISO document, manufacturer serial number/trademark, and steel grade.
- Documentation: Manufacturer must issue a declaration of conformity including dimensional data, attenuation results, and velocity measurements.
- Modifications: Blocks thicker than 25 mm are permitted for larger probe apertures.
- Annexes: Annex A (normative) covers material anisotropy and velocity determination; Annex B (informative) describes possible uses.
Applications and users
ISO 19675:2017 is used by:
- NDT technicians and inspection engineers who perform PAUT setup and calibration.
- Manufacturers of PAUT calibration blocks and ultrasonic equipment.
- Quality managers and certification bodies requiring traceable calibration artefacts.
- Laboratories and service providers conducting weld inspection, flaw detection, and material characterization using phased array ultrasonic testing.
Benefits include improved calibration consistency, reliable signal interpretation, and better inter-laboratory comparability for PAUT inspections.
Related standards
- ISO 5577 - NDT ultrasonic testing vocabulary
- EN 16018 - Terminology for ultrasonic phased arrays
- EN 10025-2 - Hot rolled structural steels (S355J0)
Keywords: ISO 19675:2017, PAUT, phased array, calibration block, ultrasonic testing, NDT, S355J0, velocity measurements, attenuation, material anisotropy.
Open preview (PDF)Non-destructive testing — Ultrasonic testing — Specification for a calibration block for phased array testing (PAUT)
